Patent Document ID: 4227319
Application ID: 06016963
Patent Flag: 1

Claim One:
1. An electro-hydraulic control simulator for generating a reaction force for a control which is displaced by an operator, which comprises: a double-action, hydraulic actuator including a piston which moves an amount X which is proportional to the displacement of said control by said operator; a displacement sensor associated with said piston for producing an output signal which is proportional to the piston displacement X; and an hydraulic actuator servocontrol loop for producing a servo signal of amplitude F, F=f(X), which represents part of the reaction force opposing the control force generated by the operator and which is also a function of the displacement X, the function F=f(X) being represented by a curve having a central linear region corresponding to a threshold zone about X=Xo, said servo-control loop including: (a) means, connected to said displacement sensor, for generating an output signal of value X-Xo; (b) means, connected to said displacement sensor, for generating an output signal of value F/X-Xo, the amplitude of said signal being constant over the central region of said curve and being staircased over the outer regions of said curve; and (c) an analog multiplication circuit connected to the outputs of said X-Xo and F/X-Xo signal generating means for performing an analog multiplication thereof.