Abstract: An electrohydraulic control system for an arm assembly of the type described in U.S. Pat. No. 4,364,540 utilizes an electric computer (microprocessor) which receives a nonlinear or harmonic signal from the rotary hydraulic motor of the arm of this assembly and converts the harmonic signal into a linear signal which is applied to a comparator as the value signal for comparison with a command signal from the computer. Similar comparators are provided for each of the hydraulic operators and the sensors thereof can provide direct actual value inputs to these comparators.