Foot trajectory following control of hexapod robot based on Udwadia–Kalaba theory

Abstract

This paper provides an adaptive robust control strategy for foot trajectory following control of hexapod robot on basis of the Udwadia–Kalaba theory. In this paper, the foot trajectory following control problem of the hexapod robot is transformed into the problem of solving the system control constraint force on basis of the Udwadia–Kalaba theory. Compared with the traditional control strategy, linearization or approximations are not required by using the Udwadia–Kalaba theory for nonlinear system such as the hexapod robot. Due to modeling error, measurement error and the change of working state, the system may have non-ideal initial conditions, vibration interference and other uncertain factors during operation, which affect the control accuracy. An adaptive robust controller is designed for solving uncertainties. Meanwhile, the stability is analyzed by using the second method of Lyapunov function. Finally, the accuracy and stability of the control method proposed are verified by establishing the leg model of the hexapod robot and conducting simulation analysis. The simulation results show that the provided adaptive control process has faster error convergence speed and response speed compared with the sliding mode control method.