Command Filtered Adaptive Control for Flexible-Joint Robots With Full-State Quantization

This article further investigates the tracking control problem of flexible-joint robot systems. Compared with existing results, all states are assumed to be quantized by a uniform quantizer, which results in discontinuous quantized signals. To address this issue, a new adaptive controller is proposed by introducing a command filter, in which the quantized virtual controller is used as input to obtain continuous signals. Thus, the discontinuity problem is avoided and the quantization influence is further compensated. It can be proven that all signals in the closed-loop system are bounded and tracking errors can converge to an arbitrarily small neighborhood of the origin. Finally, a simulation result is given to verify the practicability of the proposed method.