Feedback controller design for servo systems with dominant mechanical resonances

An estimator-based linear discrete-time controller for a high-performance two-axis miniature wheelchair drive is presented. This drive has a dominant resonance at approximately half the Nyquist frequency of the controller. The controller actively damps this resonance while simultaneously achieving a higher closed-loop bandwidth than in conventional designs. The controller design methodology is based on linear-quadratic-Gaussian (LQG) optimal control. Transformations are presented that simplify the implementation of the resulting fourth-order state estimator and linear control law. The drive is implemented with incremental-position encoders, a microprocessor, switching converters and a pair of motors.<
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