Trajectory tracking with terminal sliding mode control of cucumber picking robot manipulator based on cycloidal motion

Cucumber picking robot is the concrete application of robot technology in agriculture. Trajectory planning which enables cucumber picking robot to reach the picking target fast and stably is one of the most important research contents of cucumber picking robot. The cycloidal motion, which has the properties of continuity and zero velocity and acceleration at the ports of the bounded interval, was proposed as a feasible approach to plan trajectory in joint space of robot manipulator. Moreover, in order to achieve precise tracking of the desired trajectory, a fast and non-singular terminal sliding mode controller with the approaching law combining exponent with power function was constructed. Compared with linear sliding mode surface, it exhibits some superior properties such as fast and finite time convergence by adopting non-linear sliding mode surface. In addition, it also possesses the advantages of non-singularity and chattering-free as compared with conventional terminal sliding mode. The robustness of the controller is verified with Lyapunov stability theory. Theoretical analysis and simulation experiments show that faster and higher precision tracking performance was obtained by using the presented algorithm.