Analysis of the controller with disturbance observer on two direct drive motor system

The twin direct drive motor system connected by wire rope has many advantages such as lightweight and high stiffness, widely used in light weight actuation applications. However, it is difficult to be used in the applications which need precise position control, because of the elasticity and nonlinearity characteristic. In the study, a novel controller is proposed in order to improve the position accuracy of the twin direct drive motor system. The PID controller is used in one motor in order to realize the torque control. The 2 DOF controller with the disturbance observer (DOB) is applied in another motor in order to improve the tracking performance and reduce the external disturbance in the twin direct drive motor system. The 2 DOF controller consists of PID controller of outer loop and the controller with DOB of inner loop. Besides the controller of the whole system, we also analyzed the topological structure and dynamic equations of the twin direct drive motor system. According to the comparison simulation of the 2 DOF controller with DOB with simulation of the 2 DOF controller without DOB, we can know that the 2 DOF controller with DOB make the system achieve better performance.