Control apparatus and control method for variable mechanism

A control apparatus for a variable mechanism that includes a movable member including an engagement portion that reciprocates between two restriction members, and an actuator that drives the movable member, wherein in the variable mechanism, the actuator drives the movable member to change a predetermined mechanical characteristic of an object to be controlled, the control apparatus comprising:

• a displacement amount calculation portion that calculates an amount of displacement of the movable member from a reference position;
• an absolute position calculation portion that calculates an absolute position of the movable member based on the reference position and the amount of displacement of the movable member from the reference position;
• a movement control portion that controls movement of the movable member using the actuator based on the absolute position;
• a learning portion that, when a predetermined condition is fulfilled, drives the movable member until the engagement portion contacts one of the two restriction members, and learns the absolute position of the movable member at a time at which it is determined that displacement of the movable member is stopped, as the reference position corresponding to the one of the two restriction members, wherein when supply of electric power to the control apparatus is stopped, the learning portion learns the absolute position of the movable member at a time at which an operation of the actuator is stopped, as an initial reference position;
• a one-side displacement amount calculation portion that, when electric power is supplied to the control apparatus, drives the movable member from the initial reference position learned when the supply of electric power was stopped most recently before electric power is supplied to the control apparatus, until the engagement portion contacts the one of the two restriction members, wherein the one-side displacement amount calculation portion calculates a one-side displacement amount that is the amount of displacement of the movable member from the initial reference position until it is determined that the displacement of the movable member is stopped;
• a one-side distance calculation portion that calculates a one-side distance that is a distance from the initial reference position to the reference position learned due to fulfillment of the predetermined condition before the initial reference position was learned;
• a determination portion that determines that a foreign substance is caught in an area on a side of a site corresponding to the one of the two restriction members in a movable range of the movable member, which is restricted by the two restriction members, if the one-side displacement amount is smaller than the one-side distance;
• and
• a total displacement amount calculation portion that drives the movable member until the engagement portion contacts one of the two restriction members, and calculates the absolute position of the movable member at a time at which it is determined that the displacement of the movable member is stopped, and that drives the movable member until the engagement portion contacts the other of the two restriction members, calculates the absolute position of the movable member at a time at which it is determined that the displacement of the movable member is stopped, and calculates a total displacement amount that is an amount of displacement of the movable member between the two absolute positions, wherein if the total displacement amount is smaller than a predetermined determination value, the determination portion performs a determination regarding catching of the foreign substance, based on comparison between the one-side displacement amount and the one-side distance.

A control method for a variable mechanism that includes a movable member including an engagement portion that reciprocates between two restriction members, and an actuator that drives the movable member, wherein in the variable mechanism, the actuator drives the movable member to change a predetermined mechanical characteristic of an object to be controlled, and the control method is performed by a control apparatus, the control method comprising:

• calculating an amount of displacement of the movable member from a reference position;
• calculating an absolute position of the movable member based on the reference position and the amount of displacement of the movable member from the reference position;
• controlling movement of the movable member using the actuator based on the absolute position;
• when a predetermined condition is fulfilled, driving the movable member until the engagement portion contacts one of the two restriction members, and learning the absolute position of the movable member at a time at which it is determined that displacement of the movable member is stopped, as the reference position corresponding to the one of the two restriction members;
• when supply of electric power to the control apparatus is stopped, learning the absolute position of the movable member at a time at which an operation of the actuator is stopped, as an initial reference position;
• when electric power is supplied to the control apparatus, driving the movable member from the initial reference position learned when the supply of electric power was stopped most recently before electric power is supplied to the control apparatus, until the engagement portion contacts the one of the two restriction members, and calculating a one-side displacement amount that is the amount of displacement of the movable member from the initial reference position until it is determined that the displacement of the movable member is stopped;
• calculating a one-side distance that is a distance from the initial reference position to the reference position learned due to fulfillment of the predetermined condition before the initial reference position was learned;
• determining that a foreign substance is caught in an area on a side of a site corresponding to the one of the two restriction members in a movable range of the movable member, which is restricted by the two restriction members, if the one-side displacement amount is smaller than the one-side distance;
• and
• driving the movable member until the engagement portion contacts one of the two restriction members, calculating the absolute position of the movable member at a time at which it is determined that the displacement of the movable member is stopped, driving the movable member until the engagement portion contacts the other of the two restriction members, calculating the absolute position of the movable member at a time at which it is determined that the displacement of the movable member is stopped, and calculating a total displacement amount that is an amount of displacement of the movable member between the two absolute positions;
• and
• if the total displacement amount is smaller than a predetermined determination value, performing a determination regarding catching of the foreign substance based on comparison between the one-side displacement amount and the one-side distance.