Digital control of an experimental hydraulic manipulator

This paper considers the implementation of a complex nonlinear control law on DSP-based multiprocessor hardware, to control a three-axis hydraulic manipulator. To obtain high performance position control, a two-step approach is taken: first cancel the nonlinearities by a feedback linearisation law, then control the resulting system by a robust linear control law, using the H_∞/μ controller design method. The resulting implementation consists of one master DSP handling all I/O, and one DSP for each control law, resulting in a three processor system. It is shown that communication overhead can be kept to a minimum, allowing an efficient multiprocessor implementation.