Speed control strategy for power line inspection robot servo system considering time-varying parameters

Most servo systems in power line inspection robots consist of a motor, an independent joint, and a load. In the process of crossing obstacles, the parameters in the servo systems have conspicuous time-varying properties due to the posture changes. The time-varying properties of dynamic parameters and the flexibility of the load would cause the rotation speed of the inspection robot to fluctuate, thereby affecting the motion accuracy. In this paper, the pole placement strategy was proposed to optimize the parameters in the proportional integral (PI) controller. The optimal controller parameters were selected in different postures to ensure steady speed output in the inspection robot servo system. First, the dynamic equations of the inspection robot servo system were established. Both joint flexibility and load flexibility were considered in the modeling process. Then, the Arnoldi algorithm was used to reduce the order of the servo system, and the transfer function from the speed to the drive torque was obtained. Next, the controller parameters were optimized using the pole placement method. By reasonably selecting the pole damping coefficient, the inspection robot could obtain a stable speed output. Finally, the numerical analysis and speed control of the inspection robot in different postures were analyzed. The results showed that the control strategy of pole placement could achieve a stable rotation speed for the inspection robot.