Discrete-time control framework for robots over unreliable packet-switching communication network

This paper presents a control framework for networked robotic systems with the consideration of discrete nature of communication network and controller. In order to enhance regulation performance, a local controller is developed to transform the dynamics of robotic systems so that the output signal includes both position and velocity information. For the input/output signals of the robot, a discretization block is exploited to convert continuous-time signals to discrete-time signals, and vice versa. The issue of communication delay is coped with by utilizing wave-variable transformation, while the adverse effects of packet losses are ameliorated by a novel packet modulation. Based on the proposed control framework, the passivity of the interconnected control system and steadystate position regulation are studied. The performance of the proposed networked control system is evaluated by numerical simulations.