Robust approximate constraint-following control design based on Udwadia–Kalaba approach and experimental validation for the joint module of cooperative robot

The joint module is an essential energy source for cooperative robots. Its dynamic performance has a direct influence on the total control effect. In order to reduce the impact of uncertain factors on the dynamic performance of cooperative robots, a robust approximate constraint-following control (RACFC) algorithm based on the Udwadia–Kalaba (U–K) approach is developed in this paper to achieve the trajectory tracking of joint modules, which is a vital part of cooperative robot action. Considering the external interference and uncertainty of system parameters, we design the controller with three parts: the nominal part inhibits any trend to deviate from the constraints; the second part solves the incompatibility problem of initial conditions; and the robust part compensates for the effects of possible uncertainty. Finally, by connecting the joint module of the cooperative robot with the rapid controller prototype CSPACE, simulation and experimental validation with two different friction models are carried out, demonstrating that the designed control can remarkably enhance the system performance of joint modules.