Stabilization of a Class of Robot Systems in Fractional-Order Hold Case via Sampling Zero Dynamic Stable Approach

Robots play a significant-and growing-role in many practical fields, for example, the corresponding application in industrial and medicine field. More importantly, for the control of a robot system, a good control performance is natural and necessary requirements. And since the control of system is usually realized by a digital computer, sampling is an inevitable process in actual engineering. However, it is a well known truth that unstable zero dynamics can greatly limit the control performance of the system. This paper investigates the stabilization of a class of robot system based on the corresponding sampled-data model, which generated from the discretization with fractional-order hold (FROH). Further, the sampled-data model of the two degree of freedom (DOF) robot system is obtained and the expression and stable conditions of sampling zero dynamics are also obtained. What is more, the control strategy of the corresponding robot system is acquired using the sampling zero dynamic stable approach. Finally, numerical example is provide to illustrate the effectiveness of the proposed approach in this paper.