Force control of a jumping musculoskeletal robot with pneumatic artificial muscles

This paper introduces a method of force control for a jumping biped robot to correctly control the ground reaction force during continuous jumping. Assuming dynamic motion, such as jumping and running, the attitude of the robot depends on the dynamics in response to the ground reaction force. Therefore, controlling the ground reaction force is necessary for stabilizing the robot's motion. However, control of the ground reaction force involves a fundamental problem: feedback control does not work properly against the impact force owing to limitations in the control bandwidth. This study introduces a method for stiffness ellipse control that utilizes three antagonist pairs of six pneumatic artificial muscles. When the tip of the robot makes contact with the ground, an external force is induced in the direction of lower stiffness. By utilizing this property of the stiffness ellipse, it is possible to control the ground reaction force by feedforward control, which is not dependent on the control bandwidth. Based on this idea, impact force control at landing and jumping force control at takeoff were proposed to correctly control the ground reaction force during the continuous jumping of the robot. The results of several experiments conducted convince us that the relationship between the ground reaction force and the stiffness ellipse is almost linear, and that the ground reaction force can be controlled with high reproducibility by adjusting the stiffness ellipse.

[1]  Neville Hogan,et al.  Impedance Control: An Approach to Manipulation: Part II—Implementation , 1985 .

[2]  Takashi Matsumoto,et al.  Real time motion generation and control for biped robot -2nd report: Running gait pattern generation- , 2009, 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[3]  T. Tsuji,et al.  Controller Design for Robot with Pneumatic Artificial Muscles , 2006, 2006 SICE-ICASE International Joint Conference.

[4]  Yasuo Kuniyoshi,et al.  Design principle based on maximum output force profile for a musculoskeletal robot , 2010, Ind. Robot.

[5]  Roland Siegwart,et al.  ScarlETH: Design and control of a planar running robot , 2011, 2011 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[6]  H. Benjamin Brown,et al.  c ○ 2001 Kluwer Academic Publishers. Manufactured in The Netherlands. RHex: A Biologically Inspired Hexapod Runner ∗ , 2022 .

[7]  Yutaka Nakamura,et al.  Hopping of a monopedal robot with a biarticular muscle driven by electromagnetic linear actuators , 2012, 2012 IEEE International Conference on Robotics and Automation.

[8]  Ryosuke Tajima,et al.  Motion having a Flight Phase: Experiments Involving a One-legged Robot , 2006, 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[9]  Kiyoshi Toriumi,et al.  Effects of the Lower Leg Bi-Articular Muscle in Jumping , 2004, J. Robotics Mechatronics.

[10]  T. Oshima,et al.  Control properties induced by the existence of antagonistic pairs of bi-articular muscles-Mechanical engineering model analyses , 1994 .

[11]  Toshiaki Tsuji,et al.  Impact force control based on stiffness ellipse method using biped robot equipped with biarticular muscles , 2015, 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS).

[12]  Yasuo Kuniyoshi,et al.  Athlete Robot with applied human muscle activation patterns for bipedal running , 2010, 2010 10th IEEE-RAS International Conference on Humanoid Robots.

[13]  Koh Hosoda,et al.  Pneumatic-driven jumping robot with anthropomorphic muscular skeleton structure , 2010, Auton. Robots.

[14]  Yuri Hasegawa,et al.  Development of Rehabilitation Support Robot with Guidance Control Based on Biarticular Muscle Mechanism , 2014 .

[15]  Marc H. Raibert,et al.  Hopping in legged systems — Modeling and simulation for the two-dimensional one-legged case , 1984, IEEE Transactions on Systems, Man, and Cybernetics.