Sliding mode control method with a feedforward compensation function

Claim 1

A sliding mode control method with a feedforward compensation function for controlling a controlled object, comprising the steps of: (a) obtaining position deviation and speed deviation values of an operation parameter representative of an operating state of the controlled object and gravitational and inertial values, corresponding thereto, of a nonlinear system parameter, which vary in dependence on the operating state of the controlled object, said obtaining including the steps of: (a1) periodically detecting a command position in a command from a host processor and an actual position in feedback from a position detector; (a2) receiving inertia data and gravity load data as the inertial and gravitational values of nonlinear system parameters; and (a3) periodically calculating the position deviation and the speed deviation values in dependence upon the command and actual positions; (b) calculating a value for a manipulated variable to converge a characteristic of a control system on a switching plane in accordance with the position and speed deviation values of the operation parameter and the gravitational and inertial values of the nonlinear system parameter, said calculating including the steps of: (b1) periodically calculating a predicted maximum inertia, a predicted minimum inertia, a predicted maximum gravity load, and a predicted minimum gravity load, in dependence upon the command position, the actual position, the inertia data, and the gravity load data detected in step (a); and (b2) periodically calculating the manipulated variable in dependence upon the position deviation, the speed deviation, the predicted maximum inertia, the predicted minimum inertia, the predicted maximum gravity load, and the predicted minimum gravity load calculated in step (b1); and (c) controlling operation of the controlled object in dependence upon the manipulated variable.