Controller for non-linear position servo

In a servo system for controlling a prime mover to position a load to a commanded position having a position sensor for providing a load position signal representative of a position of the load and a controller for producing a control signal controlling activation of the prime mover to cause the load to be positioned at the commanded position as a function of a proportional amplification of a difference between a position command specifying the commanded position and the load position signal, the improvement comprising:

• an integrator integrating the difference between the position command specifying the commanded position and the load position signal and an adder adding the integrated difference to the proportional amplification of the difference;
• and wherein
• the controller includes a summer, coupled to an output of the adder and to the load position sensor, for producing the control signal as a function of a difference between the load position signal and the sum of the proportional amplification and the integration produced by the integrator.

A method of controlling a prime mover to position a load to a commanded position comprising:

• producing a load position signal representative of a position of the load;
• and
• producing a control signal controlling activation of the prime mover to cause the load to be positioned at the commanded position by producing a difference signal equal to a difference between a position command specifying the commanded position and the load position signal, amplifying the difference signal, integrating the difference signal, summing the amplified and integrated difference signal and subtracting the load position signal from a sum of the amplified and integrated difference signal to produce the control signal.