Abstract
An electronic speed controller is used for speed control of a gasoline engine for a forklift truck. This system needs a function of making engine speed follow-up to the reference speed set with open rate of the accelerator pedal. It also needs function of constant engine speed against torque disturbance, that is the load of a hydraulic pump during loading operation. In this study, we have applied H-infinity control theory to this system, and have confirmed that H-infinity Control is superior to Proportional Integrative Derivative (PID) control in robust stability and control performances from engine bench tests.