This paper addresses the modeling of a planar parallel robot including electric motors. The dynamic model of the system is derived by applying the substructure method and Lagrangian equations with multipliers in the form of redundant generalized coordinates. These equations are then transformed to the form of minimal coordinates of operational variables. Based on this form, a sliding mode controller (SMC) is designed for trajectory tracking in a task space. | Journal of Computer Science and Cybernetics, , (2017), 325–337 DOI SLIDING MODE CONTROL FOR A PLANAR PARALLEL ROBOT DRIVEN BY ELECTRIC MOTORS IN A TASK SPACE NGUYEN QUANG HOANG1 , VU DUC VUONG1,2 1 School of Mechanical Engineering, Hanoi University of Science and Technology of Electronics Engineering, Thai Nguyen University of Technology 1 2 Faculty Abstract. This paper addresses the modeling of a planar parallel robot including electric motors. The dynamic model of the system is derived by applying the substructure method and Lagrangian equations with multipliers in the form of redundant generalized coordinates. These equations are then transformed to the form of minimal coordinates of operational variables. Based on this form, a sliding mode controller (SMC) is designed for trajectory tracking in a task space. Numerical simulations in MATLAB are carried out based on the 3RRR parallel robot in order to show the effectiveness of the proposal approach. The obtained results show a good behavior of the proposed task space tracking controller. Keywords. parallel robot, electromechanical system, dynamic modeling, sliding mode control. 1. INTRODUCTION Nowadays, parallel robotic manipulators are used widely in industrial applications due to their advantages such as high stiffness, accuracy, and light links. This kind of robots has attracted numerous researchers. Many of them deal with the modeling of parallel manipulators [4, 8]. In many work such as [1, 2] the parallel manipulators are modeled by a closed loop rigid multibody system driven directly by torques/forces. To establish the dynamic equations of a parallel robot, there are some approaches proposed in literature including Lagrangian formulation with multipliers, Newton-Euler equations, the principle of virtual work, the Jourdain principle, and Kane equation such as in [2, 3, 6-8, 13, 14]. In general, manipulators are driven by electric
