Comparison of PI and PDF controls of a manipulator arm

At Lancaster University a real-time flexible, transputer based robot control system has been developed. This paper describes how this founding has been used to compare the effectiveness of two control algorithms: 1) the multivariable version of the most frequently used proportional-integral (PI) control, and 2) the multivariable version of the newer pseudo-derivative-feedback (PDF) control. Both controllers were analysed and their gain values were tuned using an approximate block diagonalisation technique. The paper develops, analyses and compares these two robot control methods for the selected Dainichikiko PT600 robot arm. The step responses of both controllers were simulated by parallel control software running on two T9000 transputers. The results obtained show that the PDF controller is faster, less sensitive to plant parameter variations and its disturbance rejection characteristics are much better, than that of the PI controller.