Tracking control for industrial robot using notch filtering system with little phase error

This paper proposes a new method for generation of a position reference that has both vibration suppression performance and fast tracking performance for industrial robots. It is important for industrial robots to drive at high speed and with high accuracy. In such cases, vibration is generated. Conventionally, the notch filter is used in order to reduce vibration. It is able to eliminate the natural frequency component, but a reference phase error is generated. The reference phase error causes locus error in the robot. Therefore, the accuracy of the robot is degraded by using a notch filter. The proposed method overcomes this problem by using the compensation gain. The proposed compensation gain is used in order to calculate the reference phase error. Compensation of the reference phase error is attained by feedforward input. Numerical and the experimental results confirm that the proposed method is valid for reducing vibration phenomena and that it decreases the phase error.