Control mechanism with actuator employing shape memory alloy and method for adjusting servo control of the control mechanism

A control mechanism comprising:

• a shape memory alloy which memorizes a predetermined dimension thereof;
• a biasing device for exerting a biasing force on the shape memory alloy and for changing dimension of the shape memory alloy, wherein the shape memory alloy and the biasing device constitute an actuator for moving a driven member which is driven by the actuator, and wherein the driven member is controlled to move in a first direction in which the shape memory alloy returns to the predetermined dimension and in a second direction in which the biasing means changes the dimension of the shape memory alloy, so as to control a position of the driven member, by the actuator;
• an operation means for performing an operation repeatedly on a basis of information upon a target position and an actual position of the driven member, and for calculating a voltage to be supplied to the shape memory alloy;
• and
• a voltage supplier having a limiting circuit for limiting a supply of the voltage, calculated by the operation means, to the shape memory alloy, when the driven member is moved in the second direction, on a basis of a result of the operation performed by the operation means.

A control mechanism for controlling a position of a driven member in a first direction and in a second direction by an actuator, the control mechanism comprising:

• a target position determination means for determining a target position to which the driven member is to be moved;
• an actual position detection means for detecting an actual position of the driven member;
• and
• a control output operation means for calculating a difference between the target position and the actual position and performing differential calculus two times on said difference to produce a control output.

A control mechanism for controlling a position of a driven member in a first direction and in a second direction by an actuator, the control mechanism comprising:

• a target value determination means for determining a target value with which the driven member is to be moved;
• an actual value detection means for detecting an actual value of the driven member;
• and
• a control output operation means for calculating a difference between the target value and the actual value and performing a phase compensation calculation a plurality of times on said difference.

A control mechanism comprising:

• a shape memory alloy which memorizes a predetermined dimension thereof;
• a biasing device for exerting a biasing force on the shape memory alloy and for changing dimension of the a shape memory alloy, wherein the shape memory alloy and the biasing device constitute an actuator for moving a driven member which is driven by the actuator, and wherein the driven member is controlled to move in a first direction in which the shape memory alloy returns to the predetermined dimension and in a second direction in which the biasing means changes the dimension of the shape memory alloy, so as to control a position of the driven member, by the actuator;
• a target position determination means for determining a target position to which the driven member is to be moved;
• an actual position detection means for detecting an actual position of the driven member;
• a control output operation means for calculating a control output by executing an operation relative to a difference between the target position and the actual position;
• and
• a compensation means for restraining heating of the shape memory alloy with respect to a result of the operation executed by the control output operation means in order to stabilize a drive control of the actuator.

A control mechanism comprising:

• a shape memory alloy which memorizes a predetermined dimension thereof;
• a biasing device for exerting a biasing force on the shape memory alloy and for changing dimension of the shape memory alloy, wherein the shape memory alloy and the biasing device constitute an actuator for moving a driven member which is driven by the actuator, and wherein the driven member is controlled to move in a first direction in which the shape memory alloy returns to the predetermined dimension and in a second direction in which the biasing means changes the dimension of the shape memory alloy, so as to control a position of the driven member, by the actuator;
• a target position determination means for determining a target position to which the driven member is to be moved;
• an actual position detection means for detecting an actual position of the driven member;
• a control output operation means for calculating a control output by executing an operation relative to a difference between the target position and the actual position;
• and
• a compensation means for correcting a voltage which is supplied to the shape memory alloy with respect to a result of the operation executed by the control output operation means, in which the correction of the voltage is made by adding an offset voltage.

A method for adjusting servo control of a control mechanism, in which the control mechanism comprises:

• a shape memory alloy which memorizes a predetermined dimension thereof;
• a biasing device for exerting a biasing force on the shape memory alloy and for changing dimension of the shape memory alloy, wherein the shape memory alloy and the biasing device constitute an actuator for moving a driven member which is driven by the actuator, and wherein the driven member is controlled to move in a first direction in which the shape memory alloy returns to the predetermined dimension and in a second direction in which the biasing means changes the dimension of the shape memory alloy, so as to control a position of the driven member, by the actuator;
• a target position determination means for determining a target position to which the driven member is to be moved;
• an actual position detection means for detecting an actual position of the driven member;
• and
• a servo control circuit which executes a servo control on the basis of information upon the target position and the actual position,
• the method comprising the steps of:
• optimizing a gain setting of the servo control circuit within a predetermined permissible range;
• detecting the actual position to which the driven member is actually driven to move, after the optimization, by the actual position detection means, and actually measuring a difference between the actual position and the target position;
• and
• making the control mechanism itself memorize the difference thus measured actually.