Damping control of variable damping compliant actuators

The development of variable impedance actuators (VIAs) has highlighted the need for proper control of passive impedance to attain suitable interaction performance. Until recently the regulation of the intrinsic impedance in VIAs is achieved in an open-loop model-based manner, mainly due to the lack of physical sensors capable of measuring impedance components such as stiffness and damping. Hence, the estimation of variable stiffness and damping has been explored, with the target to provide monitoring and feedback for potential closed loop control schemes. However, the use of the output of these estimators in the feedback control of variable impedance actuators has never been implemented/demonstrated in practice. This work contributes to the field with the development and experimental evaluation of a novel damping feedback control for a class of variable impedance compliant actuators able to realize a variable physical damping principle. The scheme is based on non-model-based damping estimation feedback to compensate model uncertainties in the action of an inner controller that uses a model-based friction estimator. Experimental results demonstrate the ability of the proposed scheme to replicate with good fidelity constant and time-varying damping levels.

[1]  Ming-Jyi Jang,et al.  Modeling and high-precision control of a ball-screw-driven stage , 2004 .

[2]  Giorgio Grioli,et al.  A real-time parametric stiffness observer for VSA devices , 2011, 2011 IEEE International Conference on Robotics and Automation.

[3]  Nikolaos G. Tsagarakis,et al.  Enhanced physical interaction performance for compliant joint manipulators using proxy-based Sliding Mode Control , 2014, 2014 11th International Conference on Informatics in Control, Automation and Robotics (ICINCO).

[4]  Claudio Melchiorri,et al.  Environment Estimation in Teleoperation Systems , 2007, Advances in Telerobotics.

[5]  S. Vijayakumar,et al.  Exploiting variable physical damping in rapid movement tasks , 2012, 2012 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM).

[6]  Koeng-Mo Sung,et al.  Variable forgetting factor linear least squares algorithm for frequency selective fading channel estimation , 2002, IEEE Trans. Veh. Technol..

[7]  Sungchul Kang,et al.  Safe arm with MR-based passive compliant joints and visco-elastic covering for service robot applications , 2003, Proceedings 2003 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2003) (Cat. No.03CH37453).

[8]  Michael Goldfarb,et al.  Modeling Piezoelectric Stack Actuators for Control of Mlcromanlpulatlon , 2022 .

[9]  S. Bittanti,et al.  Recursive least-squares identification algorithms with incomplete excitation: convergence analysis and application to adaptive control , 1990 .

[10]  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..

[11]  Nikolaos G. Tsagarakis,et al.  A compact soft actuator unit for small scale human friendly robots , 2009, 2009 IEEE International Conference on Robotics and Automation.

[12]  Ging Long Lin,et al.  A General Method for Semi-Active Feedback Control of Variable Friction Dampers , 2004 .

[13]  Young Kong Ahn,et al.  Adaptive Vibration Control by a Variable-Damping Dynamic Absorber Using ER Fluid , 1999 .

[14]  Yoshihiko Nakamura,et al.  Skill of compliance with controlled charging/discharging of kinetic energy , 2002, Proceedings 2002 IEEE International Conference on Robotics and Automation (Cat. No.02CH37292).

[15]  Nikolaos G. Tsagarakis,et al.  Real-time damping estimation for variable impedance actuators , 2014, 2014 IEEE International Conference on Robotics and Automation (ICRA).

[16]  Alessandro De Luca,et al.  A pure signal-based stiffness estimation for VSA devices , 2014, 2014 IEEE International Conference on Robotics and Automation (ICRA).

[17]  Lennart Ljung,et al.  Adaptation and tracking in system identification - A survey , 1990, Autom..

[18]  Lennart Ljung,et al.  System Identification: Theory for the User , 1987 .

[19]  Nikolaos G. Tsagarakis,et al.  Physical interaction detection and control of compliant manipulators equipped with friction clutches , 2014, 2014 IEEE International Conference on Robotics and Automation (ICRA).

[20]  Xiaoning Zhang,et al.  An electrorheological fluid damper for robots , 1995, Proceedings of 1995 IEEE International Conference on Robotics and Automation.

[21]  Inna Sharf,et al.  Contact Stiffness and Damping Estimation for Robotic Systems , 2003, Int. J. Robotics Res..

[22]  T. Nakamura,et al.  Viscous control of homogeneous ER fluid using a variable structure control , 2005, IEEE/ASME Transactions on Mechatronics.

[23]  Nikolaos G. Tsagarakis,et al.  A Variable Damping module for Variable Impedance Actuation , 2012, 2012 IEEE International Conference on Robotics and Automation.

[24]  Alin Albu-Schäffer,et al.  Nonlinear Oscillations for Cyclic Movements in Human and Robotic Arms , 2014, IEEE Transactions on Robotics.

[25]  Chih-Jer Lin,et al.  Precise positioning of piezo-actuated stages using hysteresis-observer based control , 2006 .

[26]  Chee-Meng Chew,et al.  Series damper actuator system based on MR fluid damper , 2006, Robotica.

[27]  Giorgio Grioli,et al.  A real time robust observer for an Agonist-Antagonist Variable Stiffness Actuator , 2013, 2013 IEEE International Conference on Robotics and Automation.

[28]  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.

[29]  Nikolaos G. Tsagarakis,et al.  VSA-CubeBot: A modular variable stiffness platform for multiple degrees of freedom robots , 2011, 2011 IEEE International Conference on Robotics and Automation.

[30]  Nikolaos G. Tsagarakis,et al.  On-line estimation of variable stiffness in flexible robot joints , 2012, Int. J. Robotics Res..

[31]  Paolo Bolzern,et al.  Exponential convergence of a modified directional forgetting identification algorithm , 1990 .

[32]  Manuel G. Catalano,et al.  Variable impedance actuators: A review , 2013, Robotics Auton. Syst..

[33]  Stefano Stramigioli,et al.  Contact impedance estimation for robotic systems , 2004, IEEE Transactions on Robotics.

[34]  Nikolaos G. Tsagarakis,et al.  Model-free force tracking control of piezoelectric actuators: Application to variable damping actuator , 2014, 2014 IEEE International Conference on Robotics and Automation (ICRA).