Motion control strategy of industrial direct drive robot for vibration suppression

Although it has many advantages such as high mechanical rigidity, fast dynamic response and high efficiency and precision, a direct drive robot is easy to vibrate because of sensibility to non-linearity, variety of parameter and external disturbance. This paper presents a model correction control strategy, which corrects the unmodeled dynamics of control system and suppresses disturbances by a unique control structure with a state observer and a digital low-pass filter, Theoretical and experimental results indicate that this strategy can effectively eliminate high order dynamic, nonlinearity, measurement noise and variation of load torque in the control system, and improves a direct drive robot motion control system's stability, robustness and resistance to disturbances, effectively suppresses the vibration.