Background: The conventional method using one-degree-of-freedom (1DOF) controller
for Permanent Magnet Synchronous Motor (PMSM) servo system has the trade-off problem between
the dynamic performance and the robustness.
Methods: In this paper, by using !∞ control theory, a novel robust two-degree-of-freedom (2DOF)
controller has been proposed to improve the position control performance of PMSM servo system.
Using robust control theory and 2DOF control theory, a !∞ robust position controller has been designed
and discussed in detail.
Results: The trade-off problem between the dynamic performance and robustness which exists in
one-degree-of-freedom (1DOF) control can be dealt with by the application of 2DOF control theory.
Then, through !∞ control theory, the design of robust position controller can be translated
to !∞ robust standard design problem. Moreover, the control system with robust controller has
been proved to be stable.
Conclusion: Further simulation results demonstrate that compared with the conventional PID control,
the designed control system has better robustness and attenuation to the disturbance of load