Abstract
For robots with flexible joints, the joint torque dynamics makes it difficult to control. An effective solution is to carry out a joint torque controller with fast enough dynamic response. This article is dedicated to design such a torque controller based on sliding mode technique. Three joint torque control approaches are proposed: (1) The proportional-derivative (PD)-type controller has some degree of robustness by properly selecting the control gains. (2) The direct sliding mode control approach which fully utilizes the physical properties of electric motors. (3) The sliding mode estimator approach was proposed to compensate the parameter uncertainties and the external disturbances of the joint torque system. These three joint torque controllers are tested and verified by the simulation studies with different reference torque trajectories and under different joint stiffness.
Highlights
A robot manipulator with flexible joints[1,2,3] is normally not intended by the robot designer
(2) The direct sliding mode control approach which fully utilizes the physical properties of electric motors
We propose a direct joint torque control schema without using the conventional pulse width modulation (PWM), which is dedicated to overcome these disadvantages
Summary
A robot manipulator with flexible joints[1,2,3] is normally not intended by the robot designer. For the direct sliding mode control design, we need the relation between the final discontinuous voltages applied to the motor windings and the time derivative of both switching functions. This relation can be found by using the definition given in s_d s_t f f d t. Ð41Þ where 1 and 2 are the time constant of the both low-pass filters for both robot joints Both the direct sliding mode control approach and the SME approach possess the torque tracking control property. The direct sliding mode control approach has the best control performance as expected
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
