Home Recent advances in magnetorheological materials and applications in robots and medical devices
Article Publicly Available

Recent advances in magnetorheological materials and applications in robots and medical devices

  • Lifeng Wang EMAIL logo , Xinhua Liu , Haihua Xu EMAIL logo , Qian Huang , Yuxin Jian , He Lu , Xiaojiang Zou and Tao Shen
Published/Copyright: September 8, 2025
Download Article (PDF)
Become an author with De Gruyter Brill
Submit Manuscript Author Information
Journal of Polymer Engineering
From the journal Journal of Polymer Engineering Volume 45 Issue 9

Abstract

Magnetorheological (MR) materials are smart materials whose rheological properties change significantly under the influence of magnetic fields. These materials mainly include fluids, elastomers, and greases. The components of MR materials consist of magnetic particles, a non-magnetic carrier liquid or matrix, and additives. The unique MR effect of these materials makes them widely used in robotics and medical devices. Improving the properties of MR materials and utilizing their characteristics are of great significance for the design and application of modern electromechanical devices. Therefore, this paper presents the composition, characteristics, and working principles of MR materials, as well as the latest progress in their applications in robotics and medical devices. Firstly, the composition and fabrication process of MR materials are introduced. Then, devices based on MR materials, including actuators, clutches, dampers, pumps, grippers for robots and medical devices, and MR robots, are extensively reviewed. Finally, a discussion of future research directions and technological challenges is provided as the conclusion of this review. The aim is to provide useful information to facilitate the design of robots and medical devices.

Graphical Abstract

Among the advancements of soft-bodied robots or micro-robots, MR materials exhibit the ability to deform under external magnetic fields, making them highly suitable for fabricating robots. 29 , 66 , 67 Hua et al. 68 designed an MRF-filled soft crawling robot with magnetic actuation. The robot achieves anisotropic magnetic torque-driven crawling, avoiding magnetic interference when the field is off. It demonstrates potential for applications in confined spaces, offering a novel approach to soft robotics with improved control and fabrication efficiency. McDonald et al. 69 developed an MRF-based soft robot with integrated flow control components, where motion is regulated by magnetic field-induced changes in fluid viscosity and pressure drop. This design enables multi-degree-of-freedom actuation through a single inlet and outlet, reducing the complexity of fluidic connections. The robot achieves complex behaviors such as bending, gripping, and independent control of multiple actuators, improving both autonomy and scalability while preserving compliance and adaptability. Chen et al. 70 designed a solid-liquid state transformable MRF-Robot made from an MRF. The MRF-Robot can perform diverse tasks such as large deformation, splitting, merging, object manipulation, and gradient pulling, making it suitable for biomedical applications like drug delivery and thrombus clearance. Li et al. 71 developed an untethered MRF robot encapsulated within an elastic membrane. The robot can wrap and transport delicate objects like tomatoes without causing damage, and it can also navigate through complex mazes shaped like letters. These capabilities highlight its potential for handling soft objects and operating in confined spaces. Min et al. 72 reported a stiffness-tunable, soft adhesive robot inspired by the velvet worm, utilizing an MRE that rapidly changes stiffness under an external magnetic field. This robot achieves precise adhesion control with low preload, enabling delicate grasping of soft and wrinkled surfaces without damage. The robot can unscrew nuts, and assist in mouse tumor removal surgery, showing potential in biomedical engineering (Figure 2e

Figure 1: Proportional classification of MR materials applications in robots and medical devices based on Refs. [28], [29], [30], [31], [32], [33], [34], [35 Copyright (2022), Institute of Electrical and Electronics Engineers. 28 Copyright (2023), American Chemical Society. 29 Copyright (2024), Institute of Electrical and Electronics Engineers. 30 Copyright (2020), Institute of Electrical and Electronics Engineers. 31 , 34 Copyright (2022), reprinted with permission from Tan et al. 32 Copyright (2023), Institute of Electrical and Electronics Engineers. 33 Copyright (2021), Institute of Electrical and Electronics Engineers. 35 Figure(s) reproduced with permissions from the institutions/holders mentioned.
Figure 1:

Proportional classification of MR materials applications in robots and medical devices based on Refs. [28], [29], [30], [31], [32], [33], [34], [35 Copyright (2022), Institute of Electrical and Electronics Engineers. 28 Copyright (2023), American Chemical Society. 29 Copyright (2024), Institute of Electrical and Electronics Engineers. 30 Copyright (2020), Institute of Electrical and Electronics Engineers. 31 , 34 Copyright (2022), reprinted with permission from Tan et al. 32 Copyright (2023), Institute of Electrical and Electronics Engineers. 33 Copyright (2021), Institute of Electrical and Electronics Engineers. 35 Figure(s) reproduced with permissions from the institutions/holders mentioned.

).

Keywords: magnetorheological materials; magnetorheological effect; medical devices; rehabilitation devices; magnetorheological robots

1 Introduction

Magnetorheological (MR) materials are a class of composite intelligent materials characterized by their field-responsive properties. 1 , 2 These materials are typically composed of magnetizable media uniformly dispersed within a non-magnetic matrix. 3 , 4 MR materials have low apparent viscosity and good fluidity under a zero magnetic field. However, when a magnetic field is applied to MR materials, the magnetizable medium is arranged in an orderly manner within milliseconds and behaves like a solid. 5 , 6 , 7 Under the influence of an external magnetic field, MR materials exhibit rapid and reversible changes in their rheological properties, a phenomenon known as the MR effect. 8 , 9 , 10 By adjusting the magnetic field intensity, the properties of MR materials can be controlled flexibly. 11 , 12

The MR effect is influenced by factors such as magnetic field strength, material composition, 13 , 14 , 15 temperature, 16 and particle sedimentation, 17 , 18 leading to complex behavioral characteristics in practical applications. Temperature variations, for instance, can significantly affect the rheological properties and stability of MR materials. 19 , 20 To enhance performance, extensive research has been conducted on material preparation and optimization, expanding their application potential across various engineering fields. Based on their physical state and substrate properties, MR materials are typically classified into magnetorheological fluids (MRF), 21 , 22 , 23 magnetorheological elastomers (MRE), 24 , 25 and magnetorheological greases (MRG). 26 , 27 These materials have shown great promise in robotics and medical devices. As illustrated in Figure 1, they are widely used in robotic systems for developing high-performance actuators, dampers, and clutches that enable precise motion control and effective energy dissipation. 28 , 29 , 30 , 31 , 32 , 33 In the medical field, MR materials have been increasingly applied in prosthetics, rehabilitation systems, and minimally invasive surgical tools, demonstrating significant advancements. 34 , 35 , 36

Figure 2: Application examples of MR materials in MR robots (a) the MRF-filled soft crawling robot achieves anisotropic magnetic torque-driven crawling, avoiding magnetic interference when the field is off. 68 Copyright (2020), Institute of Electrical and Electronics Engineers. (b) The MRF-based soft robot is capable of independently performing complex movements and behaviors, such as bending and selectively driving multiple actuators. 69 Copyright (2020), reprinted with permission from McDonald. (c) The solid–liquid state transformable MRF-Robot reaches out to grab and drag the plastic block. 70 Copyright (2022), American Chemical Society. (d) The untethered MRF robot can wrap and transport tomatoes without causing damage, and it can also navigate through complex mazes shaped like letters. 71 Copyright (2024), Institute of Electrical and Electronics Engineers. (e) The soft adhesive robot can assist in tumor removal surgery in mice, with potential for biomedical engineering. 72 Copyright (2024), reprinted with permission from Min. Figure(s) reproduced with permissions from the institutions/holders mentioned.
Figure 2:

Application examples of MR materials in MR robots (a) the MRF-filled soft crawling robot achieves anisotropic magnetic torque-driven crawling, avoiding magnetic interference when the field is off. 68 Copyright (2020), Institute of Electrical and Electronics Engineers. (b) The MRF-based soft robot is capable of independently performing complex movements and behaviors, such as bending and selectively driving multiple actuators. 69 Copyright (2020), reprinted with permission from McDonald. (c) The solid–liquid state transformable MRF-Robot reaches out to grab and drag the plastic block. 70 Copyright (2022), American Chemical Society. (d) The untethered MRF robot can wrap and transport tomatoes without causing damage, and it can also navigate through complex mazes shaped like letters. 71 Copyright (2024), Institute of Electrical and Electronics Engineers. (e) The soft adhesive robot can assist in tumor removal surgery in mice, with potential for biomedical engineering. 72 Copyright (2024), reprinted with permission from Min. Figure(s) reproduced with permissions from the institutions/holders mentioned.

Previous reviews have mainly focused on individual types of MR materials or their applications across various fields. However, there has been no comprehensive review that integrates the three main types of MR materials and their applications in robotics and medical devices. This gap underscores the need for a systematic review linking MR materials with device design in these fields. This article reviews recent advancements in MR materials and their applications in robotics and medical devices. The article begins by introducing the composition and fabrication methods of MR materials, followed by a discussion of recent progress in MR material-based devices such as actuators, dampers, clutches, prosthetics, and surgical tools. Finally, future research directions and technological challenges are discussed. By systematically summarizing relevant research achievements, this review aims to provide insights that will promote the broader adoption of MR materials in robotic and medical systems.

2 Materials

2.1 Constituents of MR materials

2.1.1 MRF

The performance of MRF is highly dependent on the properties of the magnetic particles, such as their shape, size, and concentration. 37 Carbonyl iron particles (CIPs) are the most common magnetic filler due to their high permeability and saturation magnetization. 38 , 39 Non-spherical particles can enhance yield stress and viscosity, but these benefits diminish at higher particle concentrations or field strengths. Increasing the magnetizable particle fraction improves stiffness and mechanical performance. Xie, L. et al. demonstrated that HVLP-based MRF exhibit superior stability and rheological properties. 23 Additionally, while non-spherical particles boost initial properties, their advantage decreases with higher CIPs content. 40

2.1.2 MRE

MRE is smart composites consisting of ferromagnetic particles embedded in an elastomeric matrix, first developed by Shiga et al. using silicone resin gels. 41 Unlike MRF and MRG, MRE exhibits field-dependent modulus and damping tunability before yield, making them ideal for vibration suppression and isolation with superior stability. 42 , 43 Recent advances include enhancing the MR effect through particle modification. 44 Zhang et al. 45 demonstrated that partial substitution of CIPs with G-Fe improves MR performance, thermal aging resistance, and reduces the Payne effect, enabling applications in tank shock absorbers. Jamari et al. 46 developed polystyrene-coated CIP-based MRE with enhanced damping and lower magnetic saturation, suitable for high-storage-modulus dampers under strong magnetic fields.

2.1.3 MRG

MRG consists of magnetic particles, base oil, thickeners, and functional additives suspended in a grease matrix. 27 The thickener’s three-dimensional network structure significantly improves sedimentation stability while maintaining strong MR effects. 47 This unique composition makes MRG particularly suitable for vibration control applications including dampers and grippers. 48 , 49

MRG formulations employ CIPs as the magnetic component dispersed in various carrier media including silicone oil and mineral oil. 50 , 51 The material performance is critically dependent on additives: lithium-based grease and graphite powder enhance overall properties, while specialized additives like nano-silica and graphene improve tribological characteristics and interfacial bonding. 25 , 52

2.2 Fabrication process of MR materials

2.2.1 Fabrication of MRF

The fabrication of MRF primarily involves mechanical mixing, ultrasonic dispersion, surface modification, and in-situ synthesis. Among these, mechanical mixing is the most widely used method due to its simplicity and effectiveness. 53 The fabrication process involves the following steps: First, dispersant, thixotropic agent, and antiwear agent are mixed in a specific ratio and dispersed into a beaker containing a carrier liquid. The mixture is mechanically stirred in a 50 °C water bath for 1 h to obtain a compound liquid. Next, CIPs are slowly added to the compound liquid under high-speed stirring, and the semi-finished liquid is obtained after 3 h. Finally, the semi-finished liquid is ball-milled at 300 rpm for 10 h with a ball-to-material ratio of 2:1 to produce the final MRF product.

2.2.2 Fabrication of MRE

The fabrication of MRE involves blending silicone rubber, CIPs, and silicone oil. 54 The silicone rubber is mixed with CIPs at a 20 % volume fraction. The mixture is then molded and cured, with anisotropic MRE requiring the application of a 270 mT magnetic field during curing to align the CIPs. For hybrid MRE, MRF is encapsulated within the MRE and sealed with steel plates. The entire process ensures uniform dispersion of CIPs in isotropic samples and aligned chains in anisotropic samples, enhancing the material’s mechanical and MR properties.

2.2.3 Fabrication of MRG

The fabrication of MRG involves a sequential saponification and mechanical mixing process. 48 , 50 The procedure initiates with dissolving 12-hydroxystearic and sebacic acids in dimethyl silicone oil (80–90 °C), followed by dropwise addition of lithium hydroxide solution for 2-h saponification. Subsequent steps include: (1) antioxidant incorporation and dehydration at 130–140 °C, (2) addition of benzoic acid and aluminum isopropyl alcohol at 85–95 °C, and (3) controlled water addition for secondary saponification. The mixture undergoes thermal thickening (150–200 °C) with CIPs dispersion, finalized by graphite/clay mineral incorporation and cooling. This optimized protocol ensures proper rheological and magnetic property development.

3 Applications of MR materials in robots and medical devices

3.1 Applications of MR materials in robots

Owing to their controllable deformation under external magnetic fields, MR materials are widely used in soft robotics and the design of key robotic components such as grippers, actuators, and dampers. 28 , 30 , 32 Some applications of MR materials in robots from 2020 to 2024 are summarized in Table 1.

Table 1:

Applications of MR materials in robots from 2020 to 2024.

Application area Type Function Improved method References
Robots Amoeboid soft robot Mimics moeba-like locomotion. Utilizes multi-material composite 3D printing and magnetic field control for enhanced flexibility Deng et al. 55
Variable stiffness snake robot Moves in complex environments. Uses innovative stiffness adjustment for improved terrain traversal and real-time control Zhang et al. 56
MRG variable stiffness soft robot Grips objects with variable stiffness. Integrates MRG layer and Halbach array for flexible magnetic field control in soft robots Huang et al. 57
MRF robot Precisely moves in narrow space. Uses IGWO algorithm to optimize PID controller for precise motion Hua et al. 58
SMA artificial muscles with MRF exoskeleton Actuates robotic grippers with variable stiffness control. Combines SMA for actuation and MRF for adjustable damping, enhancing precision and adaptability Yang et al. 59
Actuators Magnetic actuator with H-MREs Achieves bidirectional deformation control. Features programmable force distribution and self-sensing for enhanced adaptability and precision Gao et al. 60
Modular MR actuator Drives collaborative robots. Uses dual MR power chains for high torque and safety Véronneau et al. 61
MR actuator with MR bearings Enables high-speed, precise robotic motion. Integrates MR bearings for fast response, low energy consumption, and high switching frequency Zheng et al. 62
Dampers Cantilever beam with MRF for flexibility Controls force and trajectory in flexible manipulators. Utilizes MR fluid for enhanced damping and precise control of modal characteristics. Mulla et al. 63
MRE absorber Reduces vibration in suspension systems. Uses Bouc-Wen model and inverse model for current prediction Truong et al. 43
Rotary MR damper Provides high torque density with rotational damping. Integrates MR bearings for compact design and high torque-volume ratio Zhu et al. 64
Symmetric MRE absorber Suppress robotic milling chatter. Utilizes MRE for adaptive damping, enhancing stability and surface finish during milling Zhao et al. 65

3.1.1 MR robots

Among the advancements of soft-bodied robots or micro-robots, MR materials exhibit the ability to deform under external magnetic fields, making them highly suitable for fabricating robots. 29 , 66 , 67 Hua et al. 68 designed a MRF-filled soft crawling robot with magnetic actuation. The robot achieves anisotropic magnetic torque-driven crawling, avoiding magnetic interference when the field is off. It demonstrates potential for applications in confined spaces, offering a novel approach to soft robotics with improved control and fabrication efficiency. McDonald et al. 69 developed an MRF-based soft robot with integrated flow control components, where motion is regulated by magnetic field-induced changes in fluid viscosity and pressure drop. This design enables multi-degree-of-freedom actuation through a single inlet and outlet, reducing the complexity of fluidic connections. The robot achieves complex behaviors such as bending, gripping, and independent control of multiple actuators, improving both autonomy and scalability while preserving compliance and adaptability. Chen et al. 70 designed a solid-liquid state transformable MRF-Robot made from a MRF. The MRF-Robot can perform diverse tasks such as large deformation, splitting, merging, object manipulation, and gradient pulling, making it suitable for biomedical applications like drug delivery and thrombus clearance. Li et al. 71 developed an untethered MRF robot encapsulated within an elastic membrane. The robot can wrap and transport delicate objects like tomatoes without causing damage, and it can also navigate through complex mazes shaped like letters. These capabilities highlight its potential for handling soft objects and operating in confined spaces. Min et al. 72 reported a stiffness-tunable, soft adhesive robot inspired by the velvet worm, utilizing a MRE that rapidly changes stiffness under an external magnetic field. This robot achieves precise adhesion control with low preload, enabling delicate grasping of soft and wrinkled surfaces without damage. The robot can unscrew nuts, and assist in mouse tumor removal surgery, showing potential in biomedical engineering (Figure 2e).

3.1.2 MR grippers

Compared to other types of robotic grippers, MR grippers offer enhanced safety, precise control, responsiveness, and cost-effectiveness. As a result, researchers have been actively focusing on the exploration and advancement of MR grippers. Guan et al. 73 designed a soft robotic gripper based on hybrid MR materials fabricated via DIW 3D printing. This gripper integrates a fixed outer shell of MRE and an inner core of MRF. The gripper can precisely control its opening and closing through magnetic fields, achieving rapid and reversible actuation for grasping and releasing objects (Figure 3a). Choi et al. 31 developed a flexible robotic gripper using MRG to grasp objects of varying shapes without causing damage (Figure 3b). The gripper features high adaptability, adjustable gripping force, and rapid response, making it suitable for handling delicate or irregularly shaped objects. Hong et al. 74 designed a magnetic foot for a quadrupedal climbing robot, integrating electropermanent magnets and MRE. The foot provides high adhesion and traction forces, enabling the robot to climb vertically and traverse ceilings at speeds up to 0.7 m/s and 0.5 m/s, respectively (Figure 3c). Xia et al. 75 proposed a bio-inspired flexible gripper using MRF for vacuum non-cooperative target capture. The new method is inspired by the dermo-muscular sac of flatworms, adjusting stiffness through magnetic fields. The gripper can adapt to various object shapes and is suitable for capturing non-cooperative targets in space (Figure 3d).

Figure 3: Application examples of MR materials in MR grippers (a) the soft robotic gripper can precisely control its opening and closing through magnetic fields, enabling a fast and reversible drive to grab and release objects. 73 Copyright (2022), Elsevier. (b) The MRG flexible manipulator gripper grabs egg, apple, medicine bottle and sachima. 31 Copyright (2020), Institute of Electrical and Electronics Engineers. (c) The magnetic foot enables the robot to climb vertically. 74 Copyright (2022), American Association for the advancement of Science. (d) The bionic flexible gripper based on MRF grabs a cylindrical object with a diameter of 50 mm, a length of 70 mm and a weight of 47.8 g, and a space truss with a side length of 40 mm and a weight of 3.5 g. 75 Copyright (2024), IOP Publishing. Figure(s) reproduced with permissions from the institutions/holders mentioned.
Figure 3:

Application examples of MR materials in MR grippers (a) the soft robotic gripper can precisely control its opening and closing through magnetic fields, enabling a fast and reversible drive to grab and release objects. 73 Copyright (2022), Elsevier. (b) The MRG flexible manipulator gripper grabs egg, apple, medicine bottle and sachima. 31 Copyright (2020), Institute of Electrical and Electronics Engineers. (c) The magnetic foot enables the robot to climb vertically. 74 Copyright (2022), American Association for the advancement of Science. (d) The bionic flexible gripper based on MRF grabs a cylindrical object with a diameter of 50 mm, a length of 70 mm and a weight of 47.8 g, and a space truss with a side length of 40 mm and a weight of 3.5 g. 75 Copyright (2024), IOP Publishing. Figure(s) reproduced with permissions from the institutions/holders mentioned.

3.1.3 MR actuators and dampers

MR materials are well-suited for applications requiring high responsiveness and dynamic control, such as robotic milling with chatter suppression. 76 MR actuators also offer advantages including low friction, high back-drivability, and tunable stiffness, enhancing both performance and safety in robotics. Their inherent force/torque limitation further ensures safe human-robot interaction. 77 , 78 Kermani et al. 79 developed an antagonistic MR actuator combining an electric motor with a pair of MR clutches (Figure 4), utilizing the inherent output boundedness to eliminate additional sensors and complex control systems. This design achieves low inertia, wide bandwidth, and precise torque control, making it suitable for safe and high-performance human–robot interaction. Xu et al. 80 integrated an MR damper into a robotic polishing end-effector, using MRF’s variable damping properties to suppress vibrations during polishing. The design incorporates a magnetic spring mechanism and field-dependent damping force, reducing vibration amplitude by 45 % and improving surface roughness by 57.9 %, thereby significantly enhancing polishing stability and surface quality.

Figure 4: Application examples of MR materials in MR actuators and dampers: Experimental set up consisting of a KUKA LWR 4 + robot coupled to the second link of the MR actuated 5-DOF robot. 79 Copyright (2023), reprinted with permission from Kermani. Figure(s) reproduced with permissions from the institutions/holders mentioned.
Figure 4:

Application examples of MR materials in MR actuators and dampers: Experimental set up consisting of a KUKA LWR 4 + robot coupled to the second link of the MR actuated 5-DOF robot. 79 Copyright (2023), reprinted with permission from Kermani. Figure(s) reproduced with permissions from the institutions/holders mentioned.

3.2 Applications of MR materials in medical devices

MR materials have demonstrated significant potential in medical applications, particularly in the development of haptic interfaces and rehabilitation devices. 81 , 82 According to recent statistics, MR materials have been applied in medical devices with a proportion of 42.6 % (Figure 1). Some applications of MR materials in medical devices from 2020 to 2024 are summarized in Table 2.

Table 2:

Applications of MR materials in medical devices from 2020 to 2024.

Application area Type Improved method References
Haptic devices Dual-drive MRF clutch for haptic actuator Utilizes multi-layered MR fluid clutches for enhanced precision and stability in haptic devices Kikuchi et al. 83
Robot-assisted catheter/guidewire surgery system Utilizes MR fluid for haptic cues and motor current loss-speed-resistance model for force measurement Zhang et al. 84
MRE-based torque feedback system Uses MREs and permanent magnets to regulate torque for feedback Hooshiar et al. 81
Thumb tactile interface using MRF Utilizes MR fluid to extend Z-width and improve haptic sensitivity Yin et al. 85
MRF-based tactile transfer cell for surgery Utilizes MR fluid for real-time force sensing and enhanced control in robotic-assisted procedures Park et al. 86
Rehabilitation devices MR actuators in sitting/lying lower limb rehabilitation robot Utilizes MR fluids for controllable, reversible torque output; enhances safety and adaptability Cheng et al. 87
MR damper in finger rehabilitation robot Utilizes MR fluid for precise, real-time damping adjustment; enhances rehabilitation effectiveness Wang et al. 88
MR actuators in rehabilitation robot Uses MR fluid to adjust torque via current control, enabling real-time, adaptive rehabilitation assistance Xu et al. 89
MRLink in MRLift Utilizes MR fluid for real-time adjustment; enhances adaptability and comfort in lower back support Kennard et al. 90
MR damper for the knee joint of lower limb exoskeleton Uses MR fluid and permanent magnets; enhances adaptability and safety in rehabilitation exoskeleton Song et al. 91

3.2.1 MR haptic devices

MR materials have been extensively utilized in the development of haptic devices, which offer tactile feedback in medical simulations, minimally invasive surgical tools, and robot-assisted surgical systems. 92 For example, Jin et al. 35 developed an MRF-based tactile sensing robot-assisted system that provides adjustable haptic force feedback, enhancing surgical safety and precision by enabling real-time control of guidewires and catheters (Figure 5). Yin et al. 85 designed a thumb haptic interface using MRF combined with a spring element, achieving improved Z-width expansion and variable stiffness perception, which enhances telemanipulation performance in surgical robotics through realistic feedback. Liu et al. 93 developed an MRF-based force feedback master robot with optimized damper design and magnetic field modeling, improving force and torque regeneration during teleoperation. This compact and fast-response device enhances surgical accuracy and reduces radiation exposure for surgeons.

Figure 5: A robot-assisted catheter/guidewire surgery system using MRF. 35 Copyright (2021), Institute of Electrical and Electronics engineers. Figure(s) reproduced with permissions from the institutions/holders mentioned.
Figure 5:

A robot-assisted catheter/guidewire surgery system using MRF. 35 Copyright (2021), Institute of Electrical and Electronics engineers. Figure(s) reproduced with permissions from the institutions/holders mentioned.

3.2.2 MR rehabilitation devices

Rehabilitation devices aim to assist patients in recovering their physical functions through controlled and adaptive exercises. 94 MR materials have also found significant applications in rehabilitation devices. 95 , 96 Wang et al. 88 developed a finger rehabilitation robot using an MR damper that provides tunable damping force for muscle strength recovery, supporting both active and passive training modes to enhance stroke rehabilitation (Figure 6a). Song et al. 91 introduced an MR damper with a variable-displacement permanent magnet for lower limb exoskeletons. This device eliminates thermal degradation and achieves long-term stability and a high torque density (8.83 Nmm/g), while reducing ground reaction forces by up to 24.14 % (Figure 6b). Shi et al. 97 proposed an MR clutch-based drive system for cable-driven exoskeletons, featuring low inertia and high torque output, which improves dynamic performance and human–robot interaction during rehabilitation. Li et al. 98 designed a ramp-assist robotic walker with hybrid MR actuators that provide real-time damping adjustment, enhancing mobility, safety, and comfort for individuals with lower limb impairments during both rehabilitation and daily activities.

Figure 6: Application examples of MR materials in rehabilitation devices (a) a finger rehabilitation robot utilizing based on MR damper for active and passive rehabilitatio. 88 Copyright (2020), Elsevier. (b) A variable displacement permanent MR damper for lower limb exoskeletons. 91 Copyright (2023), reprinted with permission from Song. Figure(s) reproduced with permissions from the institutions/holders mentioned.
Figure 6:

Application examples of MR materials in rehabilitation devices (a) a finger rehabilitation robot utilizing based on MR damper for active and passive rehabilitatio. 88 Copyright (2020), Elsevier. (b) A variable displacement permanent MR damper for lower limb exoskeletons. 91 Copyright (2023), reprinted with permission from Song. Figure(s) reproduced with permissions from the institutions/holders mentioned.

4 Challenges and outlook

This review presents recent advances in the application of MR materials in robotics and medical devices. Due to their unique field-responsive properties, MR materials are widely used in actuators, clutches, dampers, grippers, haptic interfaces, rehabilitation devices, and MR robots. However, numerous material and technological limitations still exist in practical applications. Magnetic particle sedimentation, particularly in MRF, continues to affect long-term performance, despite strategies such as additive incorporation and surface modification. While MRE and MRG show improved sedimentation resistance, they still suffer from temperature sensitivity and long-term instability. Integrating MR materials into complex electromechanical systems also requires a better understanding of their coupled mechanical, thermal, and magnetic behaviors. Practical limitations include constraints on magnetic field strength, which can lead to higher energy consumption and heat generation. Furthermore, scalable and cost-effective fabrication methods are still lacking, posing a barrier to commercialization.

To address these challenges, future research should focus on developing novel MR materials with enhanced sedimentation resistance, thermal stability, and improved magnetic response. The use of advanced additives, surface treatments, and hybrid material systems can significantly improve performance and durability. Exploring new fabrication methods, such as 3D printing and in-situ polymerization, may enable the creation of MR materials with application-specific properties. In robotics, MR-based soft actuators and grippers hold strong potential for applications in minimally invasive surgery, rehabilitation, and automation. Enhancing their controllability and responsiveness will further improve robotic capabilities. In medical devices, MR materials support haptic feedback systems and surgical tools, with future work aiming to optimize biocompatibility, safety, and overall efficacy.

Overall, the continued advancement of MR materials and their applications in robotics and medical devices requires interdisciplinary collaboration between materials scientists, engineers, and medical professionals. With continuous innovation and research, MR materials are expected to play an even more significant role in revolutionizing robotics and medical device technologies.

Corresponding authors: Lifeng Wang and Haihua Xu, School of Mechanical Engineering, Chongqing Three Gorges University, Chongqing, China; and The Research Institute of Intelligent Manufacturing Industry Technology of SiChuan Arts and Science University, Deyang, Sichuan, China, E-mail: (L. Wang), (H. Xu)

Funding source: Natural Science Foundation of Chongqing

Award Identifier / Grant number: 2025NSCQ-LZX0010

Funding source: Science and Technology Research Project of Chongqing Education Commission

Award Identifier / Grant number: KJQN202401202,KJQN202401203

Funding source: Open Foundation of Key Laboratories of Sensing and the Research Institute ofIntelligent Manufacturing Industry Technology of Si Chuan Arts and Science university

Award Identifier / Grant number: ZNZZ2402

Funding source: Wanzhou Science and Technology Fund

Award Identifier / Grant number: wzstc-20230108

Funding source: CollegeStudents’ Innovation and Entrepreneurship Training Plan Program

Award Identifier / Grant number: 202410643002

Acknowledgments

We are thankful to the reviewers for meticulously going through the manuscript and for their great suggestions.

  1. Research ethics: Not applicable.

  2. Informed consent: Not applicable.

  3. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  4. Use of Large Language Models, AI and Machine Learning Tools: Language tools were employed for language improvement.

  5. Conflict of interest: The authors state no conflict of interest.

  6. Research funding: This work was supported by the Natural Science Foundation of Chongqing (2025NSCQ-LZX0010); Science and Technology Research Project of Chongqing Education Commission (KJQN202401202, KJQN202401203); Open Foundation of Key Laboratories of Sensing and the Research Institute of Intelligent Manufacturing Industry Technology of Si Chuan Arts and Science university (ZNZZ2402); Wanzhou Science and Technology Fund (wzstc-20230108); and College Students’ Innovation and Entrepreneurship Training Plan Program (202410643002).

  7. Data availability: Data will be available from the corresponding authors on request.

References

1. Jackson, J. A.; Messner, M. C.; Dudukovic, N. A.; Smith, W. L.; Bekker, L.; Moran, B.; Golobic, A. M.; Pascall, A. J.; Duoss, E. B.; Loh, K. J.; Spadaccini, C. M. Field Responsive Mechanical Metamaterials. Sci. Adv. 2018, 4 (12), eaau6419. https://doi.org/10.1126/sciadv.aau6419.Search in Google Scholar PubMed PubMed Central

2. Yang, Y.; Xu, Z. D.; Xu, Y. W.; Guo, Y. Q. Analysis on Influence of the Magnetorheological Fluid Microstructure on the Mechanical Properties of Magnetorheological Dampers. Smart Mater. Struct. 2020, 29 (11), 115025. https://doi.org/10.1088/1361-665X/abadd2.Search in Google Scholar

3. Bertoldi, K.; Vitelli, V.; Christensen, J.; Van Hecke, M. Flexible Mechanical Metamaterials. Nat. Rev. Mater. 2017, 2 (11), 1–11. https://doi.org/10.1038/natrevmats.2017.66.Search in Google Scholar

4. Shixu, L.; Jing, Z.; Jun, L.; Jie, F.; Miao, Y.; Song, Q. Enhancing Effect of Fe3O4/Nanolignocelluloses in Magnetorheological Fluid. Langmuir 2021, 37 (23), 7176–7184. https://doi.org/10.1021/acs.langmuir.1c00740.Search in Google Scholar PubMed

5. Liu, Y.; Lee, J.; Choi, S.; Choi, H. Silica-Coated Carbonyl Iron Microsphere Based Magnetorheological Fluid and its Damping Force Characteristics. Smart Mater. Struct. 2013, 22 (6), 065022. https://doi.org/10.1088/0964-1726/22/6/065022.Search in Google Scholar

6. Choi, J.; Han, S.; Nam, K. T.; Seo, Y. Hierarchically Structured Fe3O4 Nanoparticles for High-Performance Magnetorheological Fluids with Long-Term Stability. ACS Appl. Nano Mater. 2020, 3 (11), 10931–10940. https://doi.org/10.1021/acsanm.0c02187.Search in Google Scholar

7. Bica, I. Magnetorheological Suspension Based on Mineral Oil, Iron and Graphite Micro-Particles. J. Magn. Magn. Mater. 2004, 283 (2–3), 335–343. https://doi.org/10.1016/j.jmmm.2004.05.036.Search in Google Scholar

8. Rabinow, J. The Magnetic Fluid Clutch. Electr. Eng. 1948, 67 (12), 1167. https://doi.org/10.1109/EE.1948.6444497.Search in Google Scholar

9. Brenner, H. Rheology of a Dilute Suspension of Dipolar Spherical Particles in an External Field. J. Colloid Interface Sci. 1970, 32 (1), 141–158. https://doi.org/10.1016/0021-9797(70)90110-4.Search in Google Scholar

10. Rankin, P. J.; Horvath, A. T.; Klingenberg, D. J. Magnetorheology in Viscoplastic Media. Rheol. Acta 1999, 38 (5), 471–477. https://doi.org/10.1007/s003970050198.Search in Google Scholar

11. Liu, X.; Wang, L.; Lu, H.; Wang, D.; Chen, Q.; Wang, Z. Effect of Silicone Oil Viscosity on the Properties of Magnetorheological Fluids. Optoelectron. Adv. Mater. Rapid Commun. 2015, 9 (1-2), 226–230.Search in Google Scholar

12. Zhang, Q.; Liu, X.; Ren, Y.; Wang, L.; Hu, Y. Effect of Particle Size on the Wear Property of Magnetorheological Fluid. Adv. Mater. Sci. Eng. 2016, 2016 (1), 4740986. https://doi.org/10.1155/2016/4740986.Search in Google Scholar

13. Wang, L. Li, C. Liu, X. Lu, H. Zhang, Y. Yang, M. Influence of Novel Additives and Antiwear Agents on the Properties of PAO-Based Magnetorheological Fluids. Smart Mater. Struct. 2023, 32 (10), 105035. https://doi.org/10.1088/1361-665x/acf82f.Search in Google Scholar

14. Abdul Hadi, N. H. N.; Ismail, H.; Abdullah, M. K.; Shuib, R. K. Influence of Matrix Viscosity on the Dynamic Mechanical Performance of Magnetorheological Elastomers. J. Appl. Polym. Sci. 2020, 137 (13), 48492. https://doi.org/10.1002/app.48492.Search in Google Scholar

15. Zhao, P.; Du, T.; Ma, N.; Dong, X.; Qi, M. Effect of Interfacial Shear Strength Between Magnetic Particles and Carrier Liquid on Rheological Properties of Magnetorheological Fluids. J. Mol. Liq. 2023, 369, 120929. https://doi.org/10.1016/j.molliq.2022.120929.Search in Google Scholar

16. Kariganaur, A. K.; Kumar, H.; Arun, M. Effect of Temperature on Sedimentation Stability and Flow Characteristics of Magnetorheological Fluids with Damper as the Performance Analyser. J. Magn. Magn. Mater. 2022, 555, 169342. https://doi.org/10.1016/j.jmmm.2022.169342.Search in Google Scholar

17. Liu, X.; Wang, L.; Lu, H.; Wang, D.; Chen, Q.; Wang, Z. A Study of the Effect of Nanometer Fe3O4 Addition on the Properties of Silicone Oil-Based Magnetorheological Fluids. Mater. Manuf. Process. 2015, 30 (2), 204–209. https://doi.org/10.1080/10426914.2014.941875.Search in Google Scholar

18. Hemmatian, M.; Sedaghati, R.; Rakheja, S. Characterization and Modeling of Temperature Effect on the Shear Mode Properties of Magnetorheological Elastomers. Smart Mater. Struct. 2020, 29 (11), 115001. https://doi.org/10.1088/1361-665x/abb359.Search in Google Scholar

19. Kariganaur, A. K.; Kumar, H.; Mahalingam, A. Experimental Investigation on Thermal Stability of Dual Particle Magnetorheological Fluid and Performance. Heat Transf. Eng. 2024, 45 (17–18), 1606–1618. https://doi.org/10.1080/01457632.2023.2268871.Search in Google Scholar

20. Singh, R. K.; Sarkar, C. Characterization of Magnetorheological Brake in Shear Mode Using High-Strength MWCNTs and Fumed Silica-Based Magnetorheological Fluids at Low Magnetic Fields. J. Tribol. 2023, 145 (3), 031702. https://doi.org/10.1115/1.4056042.Search in Google Scholar

21. Ginder, J. M. Behavior of Magnetorheological Fluids. MRS Bull. 1998, 23 (8), 26–29. https://doi.org/10.1557/S0883769400030785.Search in Google Scholar

22. De Gans, B.; Duin, N.; Van Den Ende, D.; Mellema, J. The Influence of Particle Size on the Magnetorheological Properties of an Inverse Ferrofluid. J. Chem. Phys. 2000, 113 (5), 2032–2042. https://doi.org/10.1063/1.482011.Search in Google Scholar

23. Xie, L.; Choi, Y. T.; Liao, C. R.; Zeng, Z.; Wereley, N. M. Synthesis and Rheological Characteristics of High Viscosity Linear Polysiloxane Carrier Fluid-Based Magnetorheological Fluids. Smart Mater. Struct. 2021, 31 (1), 015041; https://doi.org/10.1088/1361-665x/ac3da1.Search in Google Scholar

24. Carlson, J. D.; Jolly, M. R. MR Fluid, Foam and Elastomer Devices. Mechatron. 2000, 10 (4–5), 555–569. https://doi.org/10.1016/S0957-4158(99)00064-1.Search in Google Scholar

25. Zhao, D.; Cui, J.; Dai, X.; Liu, S.; Dong, L. Magneto-Piezoresistive Characteristics of Graphene/Room Temperature Vulcanized Silicon Rubber-Silicon Rubber Magnetorheological Elastomer. J. Appl. Polym. Sci. 2021, 138 (12), 50051. https://doi.org/10.1002/app.50051.Search in Google Scholar

26. Song, L.; He, G. T.; Zeng, Z.; Ma, Y.; Li, M.; Zhang, D. S.; Wang, S.; Ran, Y. C. The Model and Simulation of Magnetorheological Grease Characteristics. Appl. Mech. Mater. 2013, 246-247, 1214–1219. https://doi.org/10.4028/www.scientific.net/AMM.246-247.1214.Search in Google Scholar

27. Dong, J. Q.; Ye, X. D.; Mao, R. S.; Wang, H. X.; Wang, J. Effects of Graphite Additive Ratio and Temperature on Rheological Properties of Magnetorheological Grease. JOM 2024, 76 (2), 911–918. https://doi.org/10.1007/s11837-023-06322-3.Search in Google Scholar

28. Yin, X.; Yan, J.; Wen, S.; Zhang, J. Magnetorheological Fluid-Filled Origami Joints with Variable Stiffness Characteristics. IEEE ASME Trans. Mechatron. 2022, 28 (3), 1546–1557. https://doi.org/10.1109/TMECH.2022.3222440.Search in Google Scholar

29. Zhao, P.; Yan, L.; Gao, X. Millirobot Based on a Phase-Transformable Magnetorheological Liquid Metal. ACS Appl. Mater. Interfaces 2023, 15 (31), 37658–37667. https://doi.org/10.1021/acsami.3c06648.Search in Google Scholar PubMed

30. Pagoli, A.; Alkhatib, M.; Mezouar, Y. A. Soft Variable Stiffness Gripper with Magnetorheological Fluids for Robust and Reliable Grasping. IEEE Robot. Autom. Lett. 2024, 9 (5), 4519–4526. https://doi.org/10.1109/LRA.2024.3382424.Search in Google Scholar

31. Choi, D. S.; Kim, T. H.; Lee, S. H.; Pang, C.; Bae, J. W.; Kim, S. Y. Beyond Human Hand: Shape-Adaptive and Reversible Magnetorheological Elastomer-Based Robot Gripper Skin. ACS Appl. Mater. Interfaces 2020, 12 (39), 44147–44155. https://doi.org/10.1021/acsami.0c11783.Search in Google Scholar PubMed

32. Tan, A. S.; Rabel, F.; Sattel, T.; Sill, Y. L.; Goldasz, J. Design and Performance Investigation of a Novel 3DOF Compact MR Damper. Smart Mater. Struct. 2022, 31 (12), 125020. https://doi.org/10.1088/1361-665x/aca12f.Search in Google Scholar

33. St-Jean, A.; Dorval, F.; Plante, J. S.; Lussier-Desbiens, A. Magnetorheological-Actuators: An Enabling Technology for Fast, Safe, and Practical Collaborative Robots. IEEE Trans. Robot. 2023, 40, 1261–1272. https://doi.org/10.1109/tro.2023.3341573.Search in Google Scholar

34. Véronneau, C.; Denis, J.; Lebel, L. P.; Denninger, M.; Blanchard, V.; Girard, A.; Plante, J. S. Multifunctional Remotely Actuated 3-DOF Supernumerary Robotic Arm Based on Magnetorheological Clutches and Hydrostatic Transmission Lines. IEEE Robot. Autom. Lett. 2020, 5 (2), 2546–2553. https://doi.org/10.1109/LRA.2020.2967327.Search in Google Scholar

35. Jin, X.; Guo, S.; Guo, J.; Shi, P.; Tamiya, T.; Hirata, H. Development of a Tactile Sensing Robot-Assisted System for Vascular Interventional Surgery. IEEE Sens. J. 2021, 21 (10), 12284–12294. https://doi.org/10.1109/JSEN.2021.3066424.Search in Google Scholar

36. Fu, Z.; Gan, X.; Liu, X.; Jian, Z.; Hu, H. Effect of Temperature on the Mechanics of Magnetorheological Fluid Damper. J. Chin. Inst. Eng. 2022, 45 (2), 97–108. https://doi.org/10.1080/02533839.2021.2012524.Search in Google Scholar

37. Roupec, J.; Michal, L.; Strecker, Z.; Kubík, M.; Macháček, O.; Choi, H. Influence of Clay-Based Additive on Sedimentation Stability of Magnetorheological Fluid. Smart Mater. Struct. 2021, 30 (2), 027001. https://doi.org/10.1088/1361-665x/abd345.Search in Google Scholar

38. Kim, H. J.; Seo, Y. Renovating Stability and Performance in Magnetorheological Fluids Through Particle Size and Shape Anisotropy. Small 2025, 21 (4), 2410011. https://doi.org/10.1002/smll.202410011.Search in Google Scholar PubMed

39. Ji, J.; Wu, X.; Tian, Z.; Xie, F.; Chen, F.; Li, H. A Novel Magnetorheological Fluid with High-Temperature Resistance. Mater. 2023, 16 (12), 4207. https://doi.org/10.3390/ma16124207.Search in Google Scholar PubMed PubMed Central

40. Sun, W.; Yu, J.; Cai, Y. Influence of Magnetic Field, Magnetic Particle Percentages, and Particle Diameters on the Stiffness of Magnetorheological Fluids. J. Intell. Mater. Syst. Struct. 2020, 31 (20), 2312–2325. https://doi.org/10.1177/1045389X20943956.Search in Google Scholar

41. Shiga, T.; Okada, A.; Kurauchi, T. Magnetroviscoelastic Behavior of Composite Gels. J. Appl. Polym. Sci. 1995, 58 (4), 787–792. https://doi.org/10.1002/app.1995.070580411.Search in Google Scholar

42. Zhao, W.; Tian, W.; Liu, P.; Li, B. Experimental Study on Vibration Suppression for Robotic Milling Using an MRE Absorber. Smart Mater. Struct. 2023, 32 (10), 105009. https://doi.org/10.1088/1361-665X/acf104.Search in Google Scholar

43. Truong, H. T.; Nguyen, X. B.; Bui, C. M. Singularity-Free Adaptive Controller for Uncertain Hysteresis Suspension Using Magnetorheological Elastomer-Based Absorber. Shock Vib. 2022, 2022 (1), 2007022. https://doi.org/10.1155/2022/2007022.Search in Google Scholar

44. Yusoff, M. S.; Yunus, N. A.; Zaki, N. M.; Mazlan, S. A.; Aziz, S. A. A.; Ismail, N. I. N.; Nik Ismail, N. I. Comprehensive Study on Physicochemical Characteristics of Magnetorheological Elastomer Featuring Epoxidized Natural Rubber. Smart Mater. Struct. 2022, 31 (5), 055017. https://doi.org/10.1088/1361-665X/ac6347.Search in Google Scholar

45. Zhang, B.; Li, Q.; Cao, Y.; Qie, J.; Zou, J.; You, J.; Lu, H.; Wang, W.; Wang, G. The Effect of Graphene-Coating Material (G-Fe) on the Dynamic Mechanical Characteristics of Magnetorheological Elastomer (MRE). Appl. Phys. A 2022, 128 (8), 657. https://doi.org/10.1007/s00339-022-05818-0.Search in Google Scholar

46. Jamari, S. K. M.; Nordin, N. A.; Ubaidillah, U.; Aziz, S. A. A.; Mazlan, S. A.; Nazmi, N. Enhancement of the Rheological Properties of Magnetorheological Elastomer via Polystyrene-Grafted Carbonyl Iron Particles. J. Appl. Polym. Sci. 2021, 138 (34), 50860. https://doi.org/10.1002/app.50860.Search in Google Scholar

47. Xu, M.; Liu, Y.; Li, J.; Xu, F.; Huang, X.; Yue, X. Review of Flexible Robotic Grippers, with a Focus on Grippers Based on Magnetorheological Materials. Mater. 2024, 17 (19), 4858. https://doi.org/10.3390/ma17194858.Search in Google Scholar PubMed PubMed Central

48. Ye, X.; Dong, J.; Wu, B.; Qing, O.; Wang, J.; Zhang, G. Design and Modeling of a Double Rod Magnetorheological Grease Damper. J. Mech. Sci. Technol. 2024, 38 (8), 4065–4075. https://doi.org/10.1007/s12206-024-0705-9.Search in Google Scholar

49. Ye, X.; Dong, J.; Wang, W.; Lu, J.; Wang, J. Design and Performance Analysis of Magnetorheological Grease Flexible Manipulator Gripper. J. Mech. Sci. Technol. 2023, 37 (3), 1243–1254. https://doi.org/10.1007/s12206-023-0212-4.Search in Google Scholar

50. Qian, K.; Wang, H.; Ye, X.; Du, M.; Wang, J. Rheological Properties of Lithium-Aluminum mixed-soap-based Magnetorheological Greases with Clay Minerals. Colloids Surf. A Physicochem. Eng. Asp. 2023, 676, 132134. https://doi.org/10.1016/j.colsurfa.2023.132134.Search in Google Scholar

51. Pan, J.; Li, R.; Wang, A. Study of Magnetorheological Grease’s Thermomagnetic Coupling Rheology. Appl. Sci. 2023, 13 (15), 8922. https://doi.org/10.3390/app13158922.Search in Google Scholar

52. Yan, H.; Li, P.; Duan, C.; Dong, X. Studies with Rheological Behavior of Composite Lithium-Based Magnetorheological Grease. Metals 2021, 11 (11), 1826. https://doi.org/10.3390/met11111826.Search in Google Scholar

53. Wang, L.; Li, C.; Liu, X.; Lu, H.; Zhang, Y.; Yang, M. Influence of Novel Additives and Antiwear Agents on the Properties of PAO-based Magnetorheological Fluids. Smart Mater. Struct. 2023, 32 (10), 105035. https://doi.org/10.1088/1361-665x/acf82f.Search in Google Scholar

54. Ananzeh, H. M.; Ramli, R.; Julai, S.; Muthalif, A. G. Mechanical Properties Comparison of Isotropic vs. Anisotropic Hybrid Magnetorheological Elastomer-Fluid. Polym. 2024, 16 (9), 1215. https://doi.org/10.3390/polym16091215.Search in Google Scholar PubMed PubMed Central

55. Deng, C.; Dong, J.; Guo, Y.; Sun, X.; Song, Z.; Li, Z. Amoeboid Soft Robot Based on Multi-Material Composite 3D Printing Technology. J. Magn. Magn. Mater. 2023, 588, 171390. https://doi.org/10.1016/j.jmmm.2023.171390.Search in Google Scholar

56. Zhang, D.; Yuan, H.; Cao, Z. Environmental Adaptive Control of a Snake-Like Robot with Variable Stiffness Actuators. IEEE/CAA J. Automatica Sin. 2020, 7 (3), 745–751. https://doi.org/10.1109/jas.2020.1003144.Search in Google Scholar

57. Huang, L.; Hu, H.; Ouyang, Q. Design and Feasibility Study of MRG-Based Variable Stiffness Soft Robot. Micromachines 2022, 13 (11), 2036. https://doi.org/10.3390/mi13112036.Search in Google Scholar PubMed PubMed Central

58. Hua, D.; Liu, X.; Sun, S.; Li, Z.; Li, Z.; Li, W. Precise Locomotion Controller Design for a Novel Magnetorheological Fluid Robot Based on Improved Gray Wolf Optimization Algorithm. Smart Mater. Struct. 2021, 30 (2), 025038. https://doi.org/10.1088/1361-665X/abd895.Search in Google Scholar

59. Yang, J.; Sun, S.; Yang, X.; Ma, Y.; Yun, G.; Chang, R.; Tang, S. Y.; Nakano, M.; Li, Z.; Du, H.; Zhang, S.; Li, W. Equipping New SMA Artificial Muscles with Controllable MRF Exoskeletons for Robotic Manipulators and Grippers. IEEE ASME Trans. Mechatron. 2022, 27 (6), 4585–4596. https://doi.org/10.1109/TMECH.2022.3157329.Search in Google Scholar

60. Gao, Y.; Deng, H.; Zhang, J.; Shu, Q.; Xu, Z.; Cao, X.; Wang, B.; Gong, X. Magnetic Actuator with Programmable Force Distribution and Self-Sensing for Bidirectional Deformation Control. Adv. Mater. Technol. 2022, 7 (10), 2200047. https://doi.org/10.1002/admt.202200047.Search in Google Scholar

61. Véronneau, C.; Denis, J.; Lhommeau, P.; St-Jean, A.; Girard, A.; Plante, J. S.; Bigué, J. P. L. Modular Magnetorheological Actuator with High Torque Density and Transparency for the Collaborative Robot Industry. IEEE Robot. Autom. Lett. 2022, 8 (2), 896–903. https://doi.org/10.1109/LRA.2022.3231524.Search in Google Scholar

62. Zheng, L.; Zhu, S.; Yang, J.; Gong, L.; Li, W.; Zhang, S.; Du, H.; Sun, S. Investigation of a Dexterous Actuator Integrated with Magnetorheological Bearings Towards High Switching Frequency and Fast Response. Smart Mater. Struct. 2024, 33 (6), 065026. https://doi.org/10.1088/1361-665X/ad469e.Search in Google Scholar

63. Mulla, T.; Kim, J. H.; Choi, S. B. Modal Characteristics of a Cantilever Beam with the Free-End Immersed in a Magnetorheological Fluid. Smart Mater. Struct. 2020, 29 (8), 084001. https://doi.org/10.1088/1361-665x/ab99d9.Search in Google Scholar

64. Zhu, S.; Gong, N.; Yang, J.; Zhang, S.; Gong, X.; Li, W.; Sun, S. Development of a Rotary Damper Integrated with Magnetorheological Bearings Toward Extremely High Torque-Volume Ratio. Mach. 2023, 11 (3), 368. https://doi.org/10.3390/machines11030368.Search in Google Scholar

65. Zhao, W.; Li, B.; Tian, W.; Liu, P.; Liao, W. Magnetorheological Elastomer Absorber-Based Chatter Suppression in Robotic Milling. Rob. Comput. Integr. Manuf. 2024, 88, 102740. https://doi.org/10.1016/j.rcim.2024.102740.Search in Google Scholar

66. Chubb, K.; Berry, D.; Burke, T. Towards an Ontology for Soft Robots: What is Soft? Bioinspir. Biomim. 2019, 14 (6), 063001. https://doi.org/10.1088/1748-3190/ab483f.Search in Google Scholar PubMed

67. Wang, L.; Yang, Y.; Chen, Y.; Majidi, C.; Iida, F.; Askounis, E.; Pei, Q. Controllable and Reversible Tuning of Material Rigidity for Robot Applications. Mater. Today 2018, 21 (5), 563–576. https://doi.org/10.1016/j.mattod.2017.10.010.Search in Google Scholar

68. Hua, D.; Liu, X.; Sun, S.; Sotelo, M. A.; Li, Z.; Li, W. A Magnetorheological Fluid-Filled Soft Crawling Robot with Magnetic Actuation. IEEE ASME Trans. Mechatron. 2020, 25 (6), 2700–2710. https://doi.org/10.1109/TMECH.2020.2988049.Search in Google Scholar

69. Mcdonald, K.; Rendos, A.; Woodman, S.; Brown, K. A.; Ranzani, T. Magnetorheological Fluid-Based Flow Control for Soft Robots. Adv. Intell. Syst. 2020, 2 (11), 2000139. https://doi.org/10.1002/aisy.202000139.Search in Google Scholar

70. Chen, Z.; Lu, W.; Li, Y.; Liu, P.; Yang, Y.; Jiang, L. Solid-Liquid State Transformable Magnetorheological Millirobot. ACS Appl. Mater. Interfaces 2022, 14 (26), 30007–30020. https://doi.org/10.1021/acsami.2c05251.Search in Google Scholar PubMed

71. Li, L.; Sun, Y.; Gong, Y.; Tong, Q.; Qi, L. Magnetorheological Fluid for Adaptive Soft Robotics. IEEE Robot. Autom. Lett. 2024, 10 (1), 620–627. https://doi.org/10.1109/LRA.2024.3511382.Search in Google Scholar

72. Min, H.; Bae, D.; Jang, S.; Lee, S.; Park, M.; Dayan, C. B.; Choi, J.; Bak, K.; Yang, Y.; Chun, S.; Sitti, M. Stiffness-Tunable Velvet Worm-Inspired Soft Adhesive Robot. Sci. Adv. 2024, 10 (47), eadp8260. https://doi.org/10.1126/sciadv.adp8260.Search in Google Scholar PubMed PubMed Central

73. Guan, R.; Zheng, H.; Liu, Q.; Ou, K.; Li, D. S.; Fan, J.; Fu, Q.; Sun, Y. DIW 3D Printing of Hybrid Magnetorheological Materials for Application in Soft Robotic Grippers. Compos. Sci. Technol. 2022, 223, 109409. https://doi.org/10.1016/j.compscitech.2022.109409.Search in Google Scholar

74. Hong, S.; Um, Y.; Park, J.; Park, H. W. Agile and Versatile Climbing on Ferromagnetic Surfaces with a Quadrupedal Robot. Sci. Rob. 2022, 7 (73), eadd1017. https://doi.org/10.1126/scirobotics.add1017.Search in Google Scholar PubMed

75. Xia, C.; Sai, H.; Xu, Z.; Zhao, C. Bioinspired Flexible Gripper for Vacuum Non-Cooperative Target Capture. Smart Mater. Struct. 2024, 33 (6), 065036. https://doi.org/10.1088/1361-665x/ad4d34.Search in Google Scholar

76. Bo, L.; Chenxin, S.; Wei, Z.; Shengli, S.; Wei, T.; Wenhe, L. A Novel Method of Suppressing Machining Vibration in Robotic Milling Using Magneto-Rheological Foam Damper. Chin. J. Aeronaut. 2024, 37 (12), 522–543. https://doi.org/10.1016/j.cja.2024.04.012.Search in Google Scholar

77. Ikeda, A.; Takano, T.; Abe, I.; Kikuchi, T.; Mimata, H.; Inomata, M. Kinematic Analysis and Evaluation of Delta-Type Haptic Device Using Twin-Driven Magnetorheological Fluid Actuator. In 2023 IEEE/SICE International Symposium on System Integration (SII); Institute of Electrical and Electronics Engineers (IEEE): Atlanta, GA, USA, 2023; pp 1–6.10.1109/SII55687.2023.10039227Search in Google Scholar

78. Zhang, P.; Kamezaki, M.; Otsuki, K.; He, S.; He, Z.; Dominguez, G. A.; Sugano, S. Development and Evaluation of a Backdrivable Vane-Type Rotary Actuator Using Magnetorheological Fluids. IEEE ASME Trans. Mechatron. 2022, 27 (6), 4863–4873. https://doi.org/10.1109/TMECH.2022.3167014.Search in Google Scholar

79. Kermani, M. R.; Pisetskiy, S.; Polushin, I.; Yang, Z. Q. Antagonistic Magneto-Rheological Actuators with Inherent Output Boundedness: An Ideal Solution for High-Performance and Human-Safe Actuation. Actuators 2023, 12 (9), 351. https://doi.org/10.3390/act12090351.Search in Google Scholar

80. Xu, D.; Hu, T. Modelling and Vibration Control of Magnetorheological-Based Polishing Tool for Robotic Polishing Process. Mech. Syst. Sig. Process. 2023, 195, 110290. https://doi.org/10.1016/j.ymssp.2023.110290.Search in Google Scholar

81. Hooshiar, A.; Payami, A.; Dargahi, J.; Najarian, S. Magnetostriction-Based Force Feedback for Robot-Assisted Cardiovascular Surgery Using Smart Magnetorheological Elastomers. Mech. Syst. Sig. Process. 2021, 161, 107918. https://doi.org/10.1016/j.ymssp.2021.107918.Search in Google Scholar

82. Zhu, J.; Hu, H.; Zhao, W.; Yang, J.; Ouyang, Q. Design and Control of Upper Limb Rehabilitation Training Robot Based on a Magnetorheological Joint Damper. Micromachines 2024, 15 (3), 301. https://doi.org/10.3390/mi15030301.Search in Google Scholar PubMed PubMed Central

83. Kikuchi, T.; Abe, I.; Nagata, T.; Yamaguchi, A.; Takano, T. Twin-Driven Actuator with Multi-Layered Disc Magnetorheological Fluid Clutches for Haptics. J. Intell. Mater. Syst. Struct. 2021, 32 (12), 1326–1335. https://doi.org/10.1177/1045389x20943958.Search in Google Scholar

84. Zhang, L.; Gu, S.; Guo, S.; Tamiya, T. A Magnetorheological Fluids-Based Robot-Assisted Catheter/Guidewire Surgery System for Endovascular Catheterization. Micromachines 2021, 12 (6), 640. https://doi.org/10.3390/mi12060640.Search in Google Scholar PubMed PubMed Central

85. Yin, X.; Wu, C.; Wen, S.; Zhang, J. Smart Design of Z-Width Expanded Thumb Haptic Interface Using Magnetorheological Fluids. IEEE Trans. Instrum. Meas. 2021, 70, 1–11. https://doi.org/10.1109/TIM.2021.3112231.Search in Google Scholar

86. Park, Y. J.; Choi, S. B. A New Tactile Transfer Cell Using Magnetorheological Materials for Robot-Assisted Minimally Invasive Surgery. Sensors 2021, 21 (9), 3034. https://doi.org/10.3390/s21093034.Search in Google Scholar PubMed PubMed Central

87. Cheng, G.; Xu, L.; Xu, J.; Liu, J.; Shi, J.; Chen, S.; Liu, L.; Liang, X.; Liu, Y. Robotic Mirror Therapy System for Lower Limb Rehabilitation. Ind. Robot 2021, 48 (2), 221–232. https://doi.org/10.1108/ir-06-2020-0112.Search in Google Scholar

88. Wang, D.; Wang, Y.; Zi, B.; Cao, Z.; Ding, H. Development of an Active and Passive Finger Rehabilitation Robot Using Pneumatic Muscle and Magnetorheological Damper. Mech. Mach. Theory 2020, 147, 103762. https://doi.org/10.1016/j.mechmachtheory.2019.103762.Search in Google Scholar

89. Xu, J.; Xu, L.; Li, Y.; Cheng, G.; Shi, J.; Liu, J.; Chen, S. A Multi-Channel Reinforcement Learning Framework for Robotic Mirror Therapy. IEEE Robot. Autom. Lett. 2020, 5 (4), 5385–5392. https://doi.org/10.1109/LRA.2020.3007408.Search in Google Scholar

90. Kennard, M.; Yagi, K.; Hassan, M.; Kadone, H.; Mochiyama, H.; Suzuki, K. Variable-Damper Control Using MR Fluid for Lower Back Support Exoskeleton. IEEE ASME Trans. Mechatron. 2022, 28 (1), 579–587. https://doi.org/10.1109/TMECH.2022.3196098.Search in Google Scholar

91. Song, J.; Zhu, A.; Tu, Y.; Zheng, C.; Cao, G. Magnetorheological Damper with Variable Displacement Permanent Magnet for Assisting the Transfer of Load in Lower Limb Exoskeleton. IEEE Trans. Neural. Syst. Rehabil. Eng. 2023, 32, 43–52. https://doi.org/10.1109/TNSRE.2023.3338969.Search in Google Scholar PubMed

92. Park, Y. J.; Lee, E. S.; Choi, S. B. A Cylindrical Grip Type of Tactile Device Using Magneto-Responsive Materials Integrated with Surgical Robot Console: Design and Analysis. Sensors 2022, 22 (3), 1085. https://doi.org/10.3390/s22031085.Search in Google Scholar PubMed PubMed Central

93. Liu, Z.; Wang, S.; Feng, F.; Xie, L. A Magnetorheological Fluid Based Force Feedback Master Robot for Vascular Interventional Surgery. J. Intell. Robot. Syst. 2022, 106 (1), 20. https://doi.org/10.1007/s10846-022-01716-y.Search in Google Scholar

94. Christie, M.; Sun, S.; Deng, L.; Du, H.; Zhang, S.; Li, W. Real-Time Adaptive Leg-Stiffness for Roll Compensation via Magnetorheological Control in a Legged Robot. Smart Mater. Struct. 2022, 31 (4), 045003. https://doi.org/10.1088/1361-665x/ac5317.Search in Google Scholar

95. Khazoom, C.; Caillouette, P.; Girard, A.; Plante, J. S. A Supernumerary Robotic Leg Powered by Magnetorheological Actuators to Assist Human Locomotion. IEEE Robot. Autom. Lett. 2020, 5 (4), 5143–5150. https://doi.org/10.1109/LRA.2020.3005629.Search in Google Scholar

96. Wang, W.; Liang, X.; Li, L.; Gong, L.; Deng, L.; Hu, X.; Zhang, S.; Sun, S. Wearable Chairless Exoskeleton Capable of Flexible Support to Relieve Muscle Fatigue for Industrial Workers. Smart Mater. Struct. 2024, 33 (12), 125041. https://doi.org/10.1088/1361-665x/ad94bb.Search in Google Scholar

97. Shi, K.; Song, A.; Li, H. Optimized Design for Cable-Driven Shoulder-Elbow Exoskeleton Robot. IEEE Access 2021, 9, 68197–68207. https://doi.org/10.1109/ACCESS.2021.3077365.Search in Google Scholar

98. Li, J.; Zhao, L.; Li, T. Robotic Walker for Slope Mobility Assistance with Active-Passive Hybrid Actuator. Chin. J. Mech. Eng. 2021, 34 (1), 100. https://doi.org/10.1186/s10033-021-00618-8.Search in Google Scholar
Received: 2025-05-26
Accepted: 2025-06-20
Published Online: 2025-09-08
Published in Print: 2025-10-27

© 2025 Walter de Gruyter GmbH, Berlin/Boston

Articles in the same Issue

  1. Frontmatter
  2. Material Properties
  3. Recent advances in magnetorheological materials and applications in robots and medical devices
  4. High performance poly ceramic hybrid composite featured with carbon fiber
  5. Laser transmission welding of ABS polymers: a systematic study of parameter-quality correlations and interfacial morphology
  6. Preparation and Assembly
  7. Highly efficient adsorption of Cu2+ and Cr6+ by polyethyleneimine-modified nanocellulose from sunflower stem pith
  8. Integrating low dielectric constant and high thermal conductivity into composite films for 5G circuit package substrate
  9. Engineering and Processing
  10. Injection molding of complex hollow products using an eco-friendly salt core technique
  11. Utilization of agro-waste-derived cellulose for eco-friendly hydrogel production in irrigation management
https://doi.org/10.1515/polyeng-2025-0091
Keywords for this article
magnetorheological materials; magnetorheological effect; medical devices; rehabilitation devices; magnetorheological robots

Articles in the same Issue

  1. Frontmatter
  2. Material Properties
  3. Recent advances in magnetorheological materials and applications in robots and medical devices
  4. High performance poly ceramic hybrid composite featured with carbon fiber
  5. Laser transmission welding of ABS polymers: a systematic study of parameter-quality correlations and interfacial morphology
  6. Preparation and Assembly
  7. Highly efficient adsorption of Cu2+ and Cr6+ by polyethyleneimine-modified nanocellulose from sunflower stem pith
  8. Integrating low dielectric constant and high thermal conductivity into composite films for 5G circuit package substrate
  9. Engineering and Processing
  10. Injection molding of complex hollow products using an eco-friendly salt core technique
  11. Utilization of agro-waste-derived cellulose for eco-friendly hydrogel production in irrigation management
Sign up now to receive a 20% welcome discount
Institutional Access
How does access work?
Have an idea on how to improve our website?
Please write us.
© 2025 De Gruyter Brill
Downloaded on 14.11.2025 from https://www.degruyterbrill.com/document/doi/10.1515/polyeng-2025-0091/html
Scroll to top button