Electric cart control system for adjustable pedal load using dynamic-parallel-distributed-compensation method

A previously developed new-concept electric cart was improved by installing a knob that allows the driver to continuously vary the pedal load between the strenuous and assisted modes. This paper explains how the pedal load is determined and a design method for the cart control system. First, the largest pedal load is determined from the standpoint of ergonomics, based on the rating of perceived exertion and the Karvonen formula. Then, a gain-scheduling cart control system is designed that guarantees the stability of the cart system for any pedal load in the allowed range, and a stability condition is derived using dynamic parallel distributed compensation. Experimental results demonstrate the validity of the cart control system.