Measurement system positioning servo controller - eliminates quantisation errors using control path model and output comparison with position

摘要

The servo controller is for a measurement device and positions a measurement element in one degree of freedom. It uses a computer which produces program dependent demand value signals for a controller whose output signal drives a position motor. The motor positions a measurement element and an actual value transducer. The arrangement prevents quantization errors of the components from affecting positioning errors. The computer contains a model of the control path whose output is compared with that of the actual value transducer. The output of the comparison circuit is in the form of a difference signal which is used to correct the controller demand signal after being passed through an evaluation circuit. The correction system ensures zero error in the static condition.