Home Angular position control system of pneumatic artificial muscles
Article Open Access

Angular position control system of pneumatic artificial muscles

  • Jakub Takosoglu EMAIL logo
Published/Copyright: July 11, 2020
Become an author with De Gruyter Brill

Abstract

This article presents a test stand used to determine the angle control of a pair of pneumatic artificial muscles PAM, which work antagonistically like natural muscles, e.g. in the human arm. The muscles were designed and produced at the Kielce University of Technology. The technical and functional parameters of the muscles were determined on the basis of experimental research. The Ziegler-Nichols method of tuning a PID controller on the basis of the step response measurement of the open system is also presented for the analysed problem. Experimental research was performed on angle control of a pair of pneumatic muscles with a PID controller.

1 Introduction

Pneumatic artificial muscles can be used as driving elements of mobile, anthropomorphic, bionic and humanoid robots; rehabilitation and physiotherapeutic manipulators as well as devices for the automation of manufacturing processes [1, 2]. Research on the technical parameters of pneumatic artificial muscles is very important to determine their application possibilities. The previous works concerned with static and dynamic characteristics of the pneumatic artificial muscles [3] and the control system applied in the Delta electro-pneumatic manipulator [4]. The subject of this work were simulation and experimental research of two types of pneumatic artificial muscles produced by two companies: Festo (Fluidic Muscle MAS and DMSP) and Shadow Robot Company (Shadow Air Muscle SAM). Due to the design and the simple structure, the pneumatic artificial muscles can be easily made independently. Many works have been created on pneumatic artificial muscles at academic and scientific centres world-wide [5, 6, 7, 8, 9, 10, 11]. Figure 1 shows a general view of various pneumatic artificial muscles, while Figure 2 presents pneumatic artificial muscles produced at the Kielce University of Technology.

Figure 1 Pneumatic artificial muscles: a) Festo Fluidic Muscle MAS b) DMSP, c) Shadow Air Muscle SAM, d) Pleated Pneumatic Artificial Muscles PPAM.
Figure 1

Pneumatic artificial muscles: a) Festo Fluidic Muscle MAS b) DMSP, c) Shadow Air Muscle SAM, d) Pleated Pneumatic Artificial Muscles PPAM.

Figure 2 Pneumatic artificial muscles made at the Kielce University of Technology: a) general view, b) connections – clamping method.
Figure 2

Pneumatic artificial muscles made at the Kielce University of Technology: a) general view, b) connections – clamping method.

The designed and produced muscle is a rubber bladder surrounded by a plastic braided mesh sleeve. The muscle connections are sealed threaded joints with bladder clamped at the ends. Before the clamping, the bladder was pre-extended to increase the relative muscle contraction and to minimize the hysteresis effect.

2 Test stand

The test stand was made on the basis of patent No. PL 223042 B1 registered at the Patent Office of the Republic of Poland [12]. The stand was made of stainless steel. The T-shaped stand consists of a base, a main column and a pivot arm, centrally attached to the column. The base has two handles to which pneumatic artificial muscles are attached. The other end of the muscles are attached to the pivot arm. The muscles act in an antagonistic manner modelled on human muscles, e.g. triceps and biceps in human arm. The contraction of one muscle under compressed air pressure extends the other muscle and rotates the arm. Muscles contract and extend alternately causing the arm to rotate. Figure 3 shows a diagram of the complete test stand and its general view.

Figure 3 Test stand: a) diagram, b) general view.
Figure 3

Test stand: a) diagram, b) general view.

Other elements of the stand include: MAB36A angle sensor attached to the pivot of the arm, MPYE-5-1 / 8-HF-010-B proportional flow control valve, air handling unit, PE5 pressure sensors, Matlab xPC Target real time system, PC and DA/AD card PCI-DAS1602/16.

The computer system uses the Rapid Control Prototyping (RPC). The system is based on Matlab xPC Target software, PCs and a card with DA/AD converters [13]. The pressure sensors and the angle sensor generate analogue voltage and are connected to the AD inputs on the card. The angle sensor measures angle of the arm rotation due to the contraction and extension of the pneumatic artificial muscles. Muscles are powered by compressed air and controlled by pressure changes inside the muscle. As the air pressure increases, the circumference simultaneously increases, and the muscle length shortens which leads to an increased muscle contraction and an axial tractive force corresponding to the stresses in the elastic mesh. The initial stage of the muscle contraction generates the greatest force, which decreases to zero with the maximum contraction, but only at constant pressure. By controlling the pressure, the transmitted force and degree of the pneumatic artificial muscle contraction can be controlled.

Despite the fact that the muscles are controlled by pressure changes, the proportional flow control valve was proposed to control the pair of pneumatic muscles. This option was chosen due to the way the valve works (Figure 4) as well as easy and optimal control of a pair of muscles.

Figure 4 Flow characteristics of MPYE valve.
Figure 4

Flow characteristics of MPYE valve.

MPYE is a 5/3-way function valve (5 - way, 3 - position). The MPYE valve is controlled by an analogue voltage. The mid position corresponding to 5V voltage closes all valve ways. The control voltage change from 5V to 0V opens the way 2 and closes the way 4 with simultaneous venting by the way 5. The control voltage change from 5V to 10V opens the way 4 and closes the way 2 with simultaneous venting by the way 3. Because pneumatic artificial muscles are connected to the ways 2 and 4, this causes alternating muscle contractions and extensions, and thus rotation of the arm. To control the pair of muscles, a part of the pressure characteristics of the valve, shown in Figure 5, was used. Accurate author’s research presented in the works [14, 15] showed asymmetry in the valve operation, leakage and non-linearity.

Figure 5 Pressure characteristics of MPYE valve.
Figure 5

Pressure characteristics of MPYE valve.

3 Experimental research

The pneumatic artificial muscles, made by a team of scientists from the Kielce University of Technology, were functionally marked as PAM-20-330. The two PAM-20-330 antagonistic muscles were used in the experimental research. All parameters of the muscles are not known yet because muscle tests are still being performed. Table 1 shows selected parameters of the PAM-20-330 muscle.

Table 1

Parameters of pneumatic artificial muscle PAM-20-330.

ParameterValue
SymbolPAM-20-330
Mode of operationSingle-acting, pulling
Internal diameter Dn20 mm
Nominal length Ln330 mm
Length of the muscle when fully contracted, Lmin290 mm
Length of the muscle when fully extended, Lmax410 mm
Max. operating pressure p0.5 MPa
Max. permissible pre-tensioning εmin24.2 % of Ln
Max. permissible contraction εmax29.3 % of Lmax
Lifting force at max. permissible operating pressure Fmax775 N

3.1 PID controller

Based on experimental observations of the PID controller tuning strategies in industrial processes, Ziegler and Nichols proposed two tuning methods. One of the methods requires measurement of the system response and is commonly used for static systems, most commonly found in control systems. The tuning method developed by Ziegler and Nichols is applicable in such systems in which the step response of an open system is without overshoots as shown in Figure 6.

Figure 6 The method for determining the parameters k, T, T0 on the basis of the step response of a system for a multi-inertial static object a), square decay rate b).
Figure 6

The method for determining the parameters k, T, T0 on the basis of the step response of a system for a multi-inertial static object a), square decay rate b).

Identification of properties of controlled objects is a basic condition for designing proper and well-functioning control systems. The analysed pneumatic muscle belongs to a group of static objects with transport delay. In order to conduct the object identification process, a step input signal was set to the proportional flow control valve. Input signal directly results from the pressure characteristics of the valve (Figure 5). The actual response obtained (black colour diagram in Figure 7) is characteristic for inertial objects and can be approximated by the characteristics of the first-order inertial element with transport delay. Transfer function of the object takes the form:

Figure 7 Step response of the open system.
Figure 7

Step response of the open system.

(1)Gs=kTs+1eT0s

where:

k – gain coefficient,

T – alignment time,

T0 – delay time.

The parameters k, T and T0 of the equation (1) was calculated based on the method proposed by Ziegler-Nichols as shown in Figure 6a. The tangent is drawn at the inflection point of the response curve. The slope of the tangent line is given by the formula R=k/T. Parameter a (Table 2) is given by: a= T0R= T0k/T. The controller tuning is based on a decay coefficient of approximately 0.25. This means that the dominant transient component decays to one fourth of its maximum value after one oscillation period (Figure 6b). The Ziegler-Nichols method based on the step response gives good results when the following condition is met:

Table 2

The controller tuning parameters according to the Ziegler-Nichols method.

ControllerOptimal parameters
kpTiTd
P1/a--
PI0.9/a3T0-
PID1.2/a2T00.5T0
(2)0.15<T0T<0.6

In the analysed case T0/T=0.17 thus this controller tuning method can be applied. The calculated parameters have the following values: k=0.021; T=0.64; T0=0.11. As you can see, the correlation between real and simulation characteristics is adequate, and the correlation coefficient is: Pearson – 0.9991, Spearman – 0.9822, Kendall – 0.9213.

The PID controller was tuned on the basis of Table 2:

Experimental research on angle control of a pair of pneumatic muscles were performed for ramp-type input signal. Figure 8a shows the characteristics of the angle change, while Figure 8b error.

Figure 8 Experimental results: a) angle, b) error.
Figure 8

Experimental results: a) angle, b) error.

On the basis of experimental research, performance of the PID controller was assessed. Basic and integral performance indices [16], which were collected in Table 3, were used for the assessment.

Table 3

Performance indices.

IndexFormulaDescription
settling timetRWith the assumed over-adjustment, it is demanded that the adjustment time was as short as possible.
steady-state errorest=limte(t)Adjustment error est appears in the system either after the change of the set value or after the change of one of the disruptions, which can potentially affect the system, or simultaneously due to the two above mentioned reasons.
IAE (Integral of Absolute Error)IAE=0e(t)dtThe modified Sartorius’ criterion indicates all errors in the adjustment system resulting from over-adjustment and under-adjustment.
ISE (Integral of Squared Error)ISE=0e2(t)dtThe criterion in which the significance of small errors is decreased, and the significance of large errors is emphasized, because of that the ISE criterion gives a more objective image of reality. The control system optimized with the use of ISE may indicate a small, slowly disappearing error of adjustment.
ITSE (Integral of the Time-weighted Squared Error)ITSE=0te2(t)dtOptimization with the use of that criterion is used to achieve a control system in which the disappearance of the error is faster.
ISC (Integral of Control)ISC=0u2(t)dtCriterion indicating the costs of control.

Table 4 presents the obtained values of indices.

Table 4

Values of the performance indices.

IndexValue
tr8.5
est5.129
IAE0.1927
ISE0.0055
ITSE−0.0716
ISC1.181

4 Conclusion

The use of a proportional directional control valve is very convenient when it is necessary to control two antagonistic pneumatic artificial muscles, as explained in Chapter 2. This type of system enables gentle and smooth inflating of the muscles with compressed air. It is possible to control the strength and the degree of muscle contraction. Due to the high dynamics of the valve, a dynamic control of the muscles, as with the use of standard divide valves, is also possible However, the use of this type of valve does not give very good results in the analysed case of angle control. It results directly from the high sensitivity of the valve with a very small range of control voltage variations 4.8-5.2V, as seen in the pressure characteristics of the valve (Figure 4). This type of system can be applied in less demanding industrial processes, where high positioning accuracy is not required. The manual [17] presents 99 examples of industrial processes in which this type of system can be successfully implemented. In order to improve the adjustment quality, two proportional pressure valves should be used, and implementation of another type of controller can be analysed, e.g. fractional controller or fuzzy logic controller [18].

References

[1] D. S. Pietrala, “Parallel manipulator with pneumatic muscle drive,” in Proceedings of 22th International Conference on Engineering Mechanics 2016 2016, pp. 458–461.Search in Google Scholar

[2] P. A. Laski, J. E. Takosoglu, and S. Blasiak, “Design of a 3-DOF tripod electro-pneumatic parallel manipulator,” Rob. Auton. Syst. vol. 72, pp. 59–70, 2015.10.1016/j.robot.2015.04.009Search in Google Scholar

[3] J. E. Takosoglu, P. A. Laski, S. Blasiak, G. Bracha, and D. Pietrala, “Determining the Static Characteristics of Pneumatic Muscles,” Meas. Control vol. 49, no. 2, pp. 62–71, Mar. 2016.10.1177/0020294016629176Search in Google Scholar

[4] J. E. Takosoglu, “Control System of Delta Manipulator With Pneumatic Artificial Muscles,” in Proceedings of 22th International Conference on Engineering Mechanics 2016 2016, pp. 546–549.Search in Google Scholar

[5] F. Daerden, D. Lefeber, B. Verrelst, and R. Van Ham, “Pleated pneumatic artificial muscles: actuators for automation and robotics,” in 2001 IEEE/ASME International Conference on Advanced Intelligent Mechatronics. Proceedings (Cat. No.01TH8556) 2001, vol. 2, pp. 738–743 vol.2.10.1109/AIM.2001.936758Search in Google Scholar

[6] F. Daerden and D. Lefeber, “Pneumatic artificial muscles: actuators for robotics and automation,” Eur. J. Mech. Environ. Eng. vol. 47, pp. 10–21, 2000.10.1109/AIM.2001.936758Search in Google Scholar

[7] I. Gaiser, “Compliant Robotics and Automation with Flexible Fluidic Actuators and Inflatable Structures,” R. Wiegand, Ed. Rijeka: IntechOpen, 2012, p. Ch. 22.10.5772/51866Search in Google Scholar

[8] G. K. Klute, J. M. Czerniecki, and B. Hannaford, “Artificial Muscles: Actuators for Biorobotic Systems,” Int. J. Rob. Res. vol. 21, no. 4, pp. 295–309, Apr. 2002.10.1177/027836402320556331Search in Google Scholar

[9] B. Verrelst, R. Van Ham, B. Vanderborght, D. Lefeber, F. Daerden, and M. Van Damme, “Second generation pleated pneumatic artificial muscle and its robotic applications,” Adv. Robot. vol. 20, no. 7, pp. 783–805, Jan. 2006.10.1163/156855306777681357Search in Google Scholar

[10] N. Yee and G. Coghill, “Modelling of a rotary pneumatic muscle,” in Proceedings of the 2002 Australasian conference on robotics and automation 2002, pp. 186–190.Search in Google Scholar

[11] Z. Zhang and M. Philen, “Pressurized artificial muscles,” J. Intell. Mater. Syst. Struct. vol. 23, no. 3, pp. 255–268, Sep. 2011.10.1177/1045389X11420592Search in Google Scholar

[12] P. A. Laski, J. E. Takosoglu, and S. Blasiak, “Urządzenie do badań, zwłaszcza dynamicznych, pneumatycznych napędów mięśniowych,” 2016.Search in Google Scholar

[13] J. E. Takosoglu, R. F. Dindorf, and P. A. Laski, “Rapid prototyping of fuzzy controller pneumatic servo-system,” Int. J. Adv. Manuf. Technol. vol. 40, no. 3–4, pp. 349–361, 2009.10.1007/s00170-007-1349-5Search in Google Scholar

[14] J. E. Takosoglu, “Experimental research of flow servo-valve,” in Proceedings of the International Conference Experimental Fluid Mechanics 2016 2016, pp. 819–823.10.1051/epjconf/201714302127Search in Google Scholar

[15] S. Blasiak, J. E. Takosoglu, and P. A. Laski, “Optimizing The Flow Rate In A Pneumatic Directional Control Valve,” in Proceedings of 20th International Conference on Engineering Mechanics 2014 2014, pp. 96–99.Search in Google Scholar

[16] I. Krzysztofik, J. Takosoglu, and Z. Koruba, “Selected methods of control of the scanning and tracking gyroscope system mounted on a combat vehicle,” Annu. Rev. Control vol. 44, pp. 173–182, 2017.10.1016/j.arcontrol.2016.10.003Search in Google Scholar

[17] S. Hesse, 99 examples of pneumatic applications Esslingen: Festo AG & Co., 2001.Search in Google Scholar

[18] J. E. Takosoglu, P. A. Laski, and S. Blasiak, “A fuzzy logic controller for the positioning control of an electro-pneumatic servo-drive,” Proc. Inst. Mech. Eng. Part I J. Syst. Control Eng. vol. 226, no. 10, pp. 1335–1343, 2012.10.1177/0959651812456498Search in Google Scholar

Received: 2019-12-02
Accepted: 2020-04-29
Published Online: 2020-07-11

© 2020 J. Takosoglu, published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Articles in the same Issue

  1. Regular Articles
  2. Fabrication of aluminium covetic casts under different voltages and amperages of direct current
  3. Inhibition effect of the synergistic properties of 4-methyl-norvalin and 2-methoxy-4-formylphenol on the electrochemical deterioration of P4 low carbon mold steel
  4. Logistic regression in modeling and assessment of transport services
  5. Design and development of ultra-light front and rear axle of experimental vehicle
  6. Enhancement of cured cement using environmental waste: particleboards incorporating nano slag
  7. Evaluating ERP System Merging Success In Chemical Companies: System Quality, Information Quality, And Service Quality
  8. Accuracy of boundary layer treatments at different Reynolds scales
  9. Evaluation of stabiliser material using a waste additive mixture
  10. Optimisation of stress distribution in a highly loaded radial-axial gas microturbine using FEM
  11. Analysis of modern approaches for the prediction of electric energy consumption
  12. Surface Hardening of Aluminium Alloy with Addition of Zinc Particles by Friction Stir Processing
  13. Development and refinement of the Variational Method based on Polynomial Solutions of Schrödinger Equation
  14. Comparison of two methods for determining Q95 reference flow in the mouth of the surface catchment basin of the Meia Ponte river, state of Goiás, Brazil
  15. Applying Intelligent Portfolio Management to the Evaluation of Stalled Construction Projects
  16. Disjoint Sum of Products by Orthogonalizing Difference-Building ⴱ
  17. The Development of Information System with Strategic Planning for Integrated System in the Indonesian Pharmaceutical Company
  18. Simulation for Design and Material Selection of a Deep Placement Fertilizer Applicator for Soybean Cultivation
  19. Modeling transportation routes of the pick-up system using location problem: a case study
  20. Pinless friction stir spot welding of aluminium alloy with copper interlayer
  21. Roof Geometry in Building Design
  22. Review Articles
  23. Silicon-Germanium Dioxide and Aluminum Indium Gallium Arsenide-Based Acoustic Optic Modulators
  24. RZ Line Coding Scheme With Direct Laser Modulation for Upgrading Optical Transmission Systems
  25. LOGI Conference 2019
  26. Autonomous vans - the planning process of transport tasks
  27. Drivers ’reaction time research in the conditions in the real traffic
  28. Design and evaluation of a new intersection model to minimize congestions using VISSIM software
  29. Mathematical approaches for improving the efficiency of railway transport
  30. An experimental analysis of the driver’s attention during train driving
  31. Risks associated with Logistics 4.0 and their minimization using Blockchain
  32. Service quality of the urban public transport companies and sustainable city logistics
  33. Charging electric cars as a way to increase the use of energy produced from RES
  34. The impact of the truck loads on the braking efficiency assessment
  35. Application of virtual and augmented reality in automotive
  36. Dispatching policy evaluation for transport of ready mixed concrete
  37. Use of mathematical models and computer software for analysis of traffic noise
  38. New developments on EDR (Event Data Recorder) for automated vehicles
  39. General Application of Multiple Criteria Decision Making Methods for Finding the Optimal Solution in City Logistics
  40. The influence of the cargo weight and its position on the braking characteristics of light commercial vehicles
  41. Modeling the Delivery Routes Carried out by Automated Guided Vehicles when Using the Specific Mathematical Optimization Method
  42. Modelling of the system “driver - automation - autonomous vehicle - road”
  43. Limitations of the effectiveness of Weigh in Motion systems
  44. Long-term urban traffic monitoring based on wireless multi-sensor network
  45. The issue of addressing the lack of parking spaces for road freight transport in cities - a case study
  46. Simulation of the Use of the Material Handling Equipment in the Operation Process
  47. The use of simulation modelling for determining the capacity of railway lines in the Czech conditions
  48. Proposals for Using the NFC Technology in Regional Passenger Transport in the Slovak Republic
  49. Optimisation of Transport Capacity of a Railway Siding Through Construction-Reconstruction Measures
  50. Proposal of Methodology to Calculate Necessary Number of Autonomous Trucks for Trolleys and Efficiency Evaluation
  51. Special Issue: Automation in Finland
  52. 5G Based Machine Remote Operation Development Utilizing Digital Twin
  53. On-line moisture content estimation of saw dust via machine vision
  54. Data analysis of a paste thickener
  55. Programming and control for skill-based robots
  56. Using Digital Twin Technology in Engineering Education – Course Concept to Explore Benefits and Barriers
  57. Intelligent methods for root cause analysis behind the center line deviation of the steel strip
  58. Engaging Building Automation Data Visualisation Using Building Information Modelling and Progressive Web Application
  59. Real-time measurement system for determining metal concentrations in water-intensive processes
  60. A tool for finding inclusion clusters in steel SEM specimens
  61. An overview of current safety requirements for autonomous machines – review of standards
  62. Expertise and Uncertainty Processing with Nonlinear Scaling and Fuzzy Systems for Automation
  63. Towards online adaptation of digital twins
  64. Special Issue: ICE-SEAM 2019
  65. Fatigue Strength Analysis of S34MnV Steel by Accelerated Staircase Test
  66. The Effect of Discharge Current and Pulse-On Time on Biocompatible Zr-based BMG Sinking-EDM
  67. Dynamic characteristic of partially debonded sandwich of ferry ro-ro’s car deck: a numerical modeling
  68. Vibration-based damage identification for ship sandwich plate using finite element method
  69. Investigation of post-weld heat treatment (T6) and welding orientation on the strength of TIG-welded AL6061
  70. The effect of nozzle hole diameter of 3D printing on porosity and tensile strength parts using polylactic acid material
  71. Investigation of Meshing Strategy on Mechanical Behaviour of Hip Stem Implant Design Using FEA
  72. The effect of multi-stage modification on the performance of Savonius water turbines under the horizontal axis condition
  73. Special Issue: Recent Advances in Civil Engineering
  74. The effects of various parameters on the strengths of adhesives layer in a lightweight floor system
  75. Analysis of reliability of compressed masonry structures
  76. Estimation of Sport Facilities by Means of Technical-Economic Indicator
  77. Integral bridge and culvert design, Designer’s experience
  78. A FEM analysis of the settlement of a tall building situated on loess subsoil
  79. Behaviour of steel sheeting connections with self-drilling screws under variable loading
  80. Resistance of plug & play N type RHS truss connections
  81. Comparison of strength and stiffness parameters of purlins with different cross-sections of profiles
  82. Bearing capacity of floating geosynthetic encased columns (GEC) determined on the basis of CPTU penetration tests
  83. The effect of the stress distribution of anchorage and stress in the textured layer on the durability of new anchorages
  84. Analysis of tender procedure phases parameters for railroad construction works
  85. Special Issue: Terotechnology 2019
  86. The Use of Statistical Functions for the Selection of Laser Texturing Parameters
  87. Properties of Laser Additive Deposited Metallic Powder of Inconel 625
  88. Numerical Simulation of Laser Welding Dissimilar Low Carbon and Austenitic Steel Joint
  89. Assessment of Mechanical and Tribological Properties of Diamond-Like Carbon Coatings on the Ti13Nb13Zr Alloy
  90. Characteristics of selected measures of stress triaxiality near the crack tip for 145Cr6 steel - 3D issues for stationary cracks
  91. Assessment of technical risk in maintenance and improvement of a manufacturing process
  92. Experimental studies on the possibility of using a pulsed laser for spot welding of thin metallic foils
  93. Angular position control system of pneumatic artificial muscles
  94. The properties of lubricated friction pairs with diamond-like carbon coatings
  95. Effect of laser beam trajectory on pocket geometry in laser micromachining
  96. Special Issue: Annual Engineering and Vocational Education Conference
  97. The Employability Skills Needed To Face the Demands of Work in the Future: Systematic Literature Reviews
  98. Enhancing Higher-Order Thinking Skills in Vocational Education through Scaffolding-Problem Based Learning
  99. Technology-Integrated Project-Based Learning for Pre-Service Teacher Education: A Systematic Literature Review
  100. A Study on Water Absorption and Mechanical Properties in Epoxy-Bamboo Laminate Composite with Varying Immersion Temperatures
  101. Enhancing Students’ Ability in Learning Process of Programming Language using Adaptive Learning Systems: A Literature Review
  102. Topical Issue on Mathematical Modelling in Applied Sciences, III
  103. An innovative learning approach for solar power forecasting using genetic algorithm and artificial neural network
  104. Hands-on Learning In STEM: Revisiting Educational Robotics as a Learning Style Precursor
Downloaded on 21.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/eng-2020-0077/html
Scroll to top button