Method and apparatus for pulse-modulated feedback control

摘要

A control system and method for controlling a plant based on feedback is described. In some embodiments, the control system uses pulse-modulated (PM) control to overcome friction stickiness.

主权项

1. A method of controlling movement or position of an object coupled to one of a motor, an engine, a pump, and a control valve associated with a system, the method comprising a repetitive sequence of the following:
(a) obtaining actual values corresponding to a position of the object, wherein obtaining the actual values comprises sampling values representing the object's actual position, wherein the object position is controllable by delivering control signals to the system; (b) receiving a sequence of command position values; (c) generating a sequence of impulse signals based upon comparing ones of the actual values to ones of the command position values, wherein comparing an actual value to a command position value includes:
if the difference between the command position value and the actual value is greater than an upper bound of error, generating an impulse signal having a first magnitude value;if the difference between the command position value and the actual value is less than a lower bound of error, generating an impulse signal having a second magnitude value; andif the difference between the command position value and the actual value is neither greater than the upper bound of error nor less than the lower bound of error, generating an impulse signal having a third magnitude value; (d) applying the sequence of impulse values signals to the system to accurately control the position of the object while overcoming nonlinear static friction, Wherein the first, second, and third magnitude values are different from one another and do not change during successive iterations of the repetitive sequence, wherein the first magnitude value is large enough to overcome non-linear forces opposing object movement in the first direction and the second magnitude value is large enough to overcome nonlinear forces opposing object movement in the second direction, wherein the third magnitude value is smaller than a value which would invoke a nonlinearity in the system.