Bandwidth parameterized disturbance observer composite sliding mode coordination control for closed chain mechanisms

To solve the control problem of joint coordination for closed chain mechanisms, the bandwidth-parameterized disturbance observer composite sliding mode control on constant rate reaching law is proposed in the coupling space. The disturbance observer (DOB) retains the computational structure of the extended state observer (ESO) and estimates the disturbance with the combinations of proportional, integral and differential of the observation error of ESO. The combinations with the proposed DOB and sliding mode control (SMC) not only relax the boundary condition of the SMC's switching gain, but also eliminate the chattering of SMC. The switching gain of SMC can be calculated according to the saturation limitation of the actuator, and the other control parameters can be tuned with bandwidth parameterization method. The simulations and experiments illustrate that the composite control scheme can effectively solve the problem of coordinated control to closed chain mechanism within the system limitation by clear parameter physical meanings and easy adjustments. © 2020, Editorial Department of Control Theory & Applications South China University of Technology. All right reserved.