Nonlinear disturbance observer based torque control for series elastic actuator

This paper presents a practical control approach for series elastic actuators(SEAs) to generate the desired torque. Specifically, the controller is applicable to both linear and nonlinear SEAs and it works well even in the presence of unknown payload parameters and external disturbances. Via the analysis and transformation of the SEA dynamics, a lumped disturbance signal is constructed and a form convenient for controller design is developed. Then, a nonlinear disturbance observer(NDOB) and a sliding-mode control scheme are introduced to synthesize the control law. The performance of the proposed controller is theoretically ensured by Lyapunov analysis. Taking a nonlinear SEA for instance, a series of simulations and hardware experiments are carried out. The results suggest the effectiveness and superior performance of the proposed method for SEA torque control by comparing it with the cascade-PID controller.

[1]  Gong Chen,et al.  Human–Robot Interaction Control of Rehabilitation Robots With Series Elastic Actuators , 2015, IEEE Transactions on Robotics.

[2]  Chi Zhu,et al.  Power analysis of a series elastic actuator for ankle joint gait rehabilitation , 2015, 2015 IEEE International Conference on Robotics and Automation (ICRA).

[3]  Nevio Luigi Tagliamonte,et al.  Rendering viscoelasticity with Series Elastic Actuators using cascade control , 2014, 2014 IEEE International Conference on Robotics and Automation (ICRA).

[4]  Nevio Luigi Tagliamonte,et al.  Passivity constraints for the impedance control of series elastic actuators , 2014, J. Syst. Control. Eng..

[5]  Nikolaos G. Tsagarakis,et al.  Development and control of a series elastic actuator equipped with a semi active friction damper for human friendly robots , 2014, Robotics Auton. Syst..

[6]  Paolo Fiorini,et al.  Human-adaptive control of series elastic actuators , 2014, Robotica.

[7]  Nikolaos G. Tsagarakis,et al.  Terminal sliding-mode based force tracking control of piezoelectric actuators for variable physical damping system , 2014, 2014 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[8]  Jian Chu,et al.  VELOCITY CONTROL OF SERIAL ELASTIC ACTUATOR BASED ON EKF ESTIMATOR AND NEURAL NETWORK , 2013 .

[9]  Gianluca Palli,et al.  On the control of redundant robots with variable stiffness actuation , 2012, 2012 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[10]  Gordon Wyeth,et al.  Demonstrating the safety and performance of a velocity sourced series elastic actuator , 2008, 2008 IEEE International Conference on Robotics and Automation.

[11]  Weiping Li,et al.  Applied Nonlinear Control , 1991 .

[12]  Jim Euchner.  Design , 2014, Catalysis from A to Z.

[13]  Wilian M. dos Santos,et al.  Impedance Control of a Rotary Series Elastic Actuator for Knee Rehabilitation , 2014 .

[14]  J. Koenderink.  Q… , 2014, Les noms officiels des communes de Wallonie, de Bruxelles-Capitale et de la communaute germanophone.

[15]  G.A. Pratt,et al.  Late motor processing in low-impedance robots: impedance control of series-elastic actuators , 2004, Proceedings of the 2004 American Control Conference.

[16]  Paolo Fiorini,et al.  Robust Force Control of Series Elastic Actuators , 2014 .

[17]  D. G. Caldwell,et al.  Design, modeling and control of a series elastic actuator for an assistive knee exoskeleton , 2012, 2012 4th IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob).

[18]  Bram Vanderborght,et al.  Torsion MACCEPA: A novel compact compliant actuator designed around the drive axis , 2015, 2015 IEEE International Conference on Robotics and Automation (ICRA).

[19]  M. Tomizuka,et al.  A Compact Rotary Series Elastic Actuator for Human Assistive Systems , 2012, IEEE/ASME Transactions on Mechatronics.

[20]  Hartmut Geyer,et al.  Control and evaluation of series elastic actuators with nonlinear rubber springs , 2015, 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS).

[21]  Jun Yang,et al.  Disturbance Observer-Based Control: Methods and Applications , 2014 .

[22]  G. Hirzinger,et al.  A new variable stiffness design: Matching requirements of the next robot generation , 2008, 2008 IEEE International Conference on Robotics and Automation.

[23]  Matthew M. Williamson,et al.  Series elastic actuators , 1995, Proceedings 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Human Robot Interaction and Cooperative Robots.

[24]  Berno J. E. Misgeld,et al.  Robust control of compliant actuators using positive real ℋ2-controller synthesis , 2014, 2014 American Control Conference.

[25]  Meng Wang,et al.  A novel sliding mode control for series elastic actuator torque tracking with an extended disturbance observer , 2015, 2015 IEEE International Conference on Robotics and Biomimetics (ROBIO).

[26]  Luis Sentis,et al.  A new prismatic series elastic actuator with compact size and high performance , 2012, 2012 IEEE International Conference on Robotics and Biomimetics (ROBIO).

[27]  M. Tomizuka,et al.  Control of Rotary Series Elastic Actuator for Ideal Force-Mode Actuation in Human–Robot Interaction Applications , 2009, IEEE/ASME Transactions on Mechatronics.

[28]  Masayoshi Tomizuka,et al.  Gait phase-based smoothed sliding mode control for a rotary series elastic actuator installed on the knee joint , 2010, Proceedings of the 2010 American Control Conference.