Patent ID: 7886535

Claim:
A position control method for a shape memory alloy actuator that controls the length of a shape memory alloy to a predetermined length based on the value of resistance of the shape memory alloy with expansion/contraction thereof resulting from phase transformation caused by heating by power supply to thereby control the position of a moving body provided on the shape memory alloy, comprising: a commanded resistance value setting step of setting a commanded resistance value that corresponds to the predetermined length; a resistance value measurement step of measuring the value of resistance with expansion/contraction of the shape memory alloy; a resistance value comparison step of comparing the commanded resistance value set in the commanded resistance value setting step and the resistance value measured in the resistance value measurement step; a first control step of controlling the length of the shape memory alloy using a first gain based on the result of comparison obtained in the resistance value comparison step until the commanded resistance value is reached; a termination determination step of making a determination as to a condition for terminating the first control step in the first control step; and a second control step of keeping the moving body stationary, upon determination of termination in the termination determination step, by retaining the length of the shape memory alloy using a second gain smaller than the first gain based on the result of the comparison, wherein the second control step is continued until a commanded resistance value is set again, thereby performing position control of the moving body.