Device for position control

A control device comprising:

• a first generator delivering a first and second identical signals, dephased with respect to each other by 90.degree.;
• an angular position pickup of the resolver type, having a rotor coupled to a component part whose angular position is to be controlled, said positioning pickup having two inputs connected to said first generator for receiving said first and second signals, respectively, and an output for delivering a measurement signal whose phase is representative of the actual angular position of said component;
• a second generator for receiving a digital instruction message in the form of a binary word and for delivering an instruction signal of the same frequency as the first and second signals and having a phase representative of the desired angular position of said component;
• a deviation signal generator connected to the output of said angular position pickup and to said second generator for delivering a deviation signal representative of the dephasing between the measurement signal and the instruction signal, said deviation signal generator comprises a synchronous demodulator for receiving a control signal of frequency equal to that of said instruction signal and in phase with the latter, and made up of rectangular pulses of duration equal to one-half of their cycle, so that, in the course of successive half-cycles of the control signal, the gain between an input of the demodulator receiving the measurement signal and an output of the demodulator linked to the output of the deviation signal generator will pass from a positive value to the opposite negative value;
• and
• a control device for controlling the angular position of said component as a function of the deviation signal, characterized by the fact that;
• each one of said first and second signals generated by said first generator is a digital approximation of a sinusoidal signal consisting of alternating cycles, each alternating cycle comprising several stages for producing a reduced rate of harmonics,
• said deviation signal generator compares directly the phase of the unfiltered output signal from said pickup with the phase of said instruction signal.