Position control system

A position control system comprising:

• a first moveable member;
• a first driving means communicating with the first movable member and for moving the first moveable member;
• a second moveable member, the first movable member being slidably attached to the second moveable member;
• second and third driving means communicating with the second movable member and for moving the second movable member;
• the first moveable member being moveable on the second moveable member by the first driving means along a horizontal axis, the second moveable member having two ends engaged to two vertical members and vertically moveable by the second and third driving means along the vertical members;
• and
• a position control apparatus for controlling a position of the first moveable member in vertical and horizontal directions comprising:
• a first servo controlling means for controlling the position of the first moveable member on the second moveable member in response to a first position control command, the first position control command for moving the first moveable member along the horizontal axis;
• a common position instructing means for outputting a second position control command;
• second and third servo controlling means for respectively controlling vertical positions of the two ends of the second moveable member along the two vertical members;
• a first vertical position correction means for calculating a first vertical position correction signal in response to the position of the first moveable member, the first vertical position correction signal and the second position control command being cooperatively applied to the second servo controlling means for moving one of the two second movable member ends along a corresponding one of the two vertical members;
• and
• a second vertical position correction means for calculating a second vertical position correction signal in response to the position of the first moveable member, the second vertical position correction signal and the second position control command being cooperatively applied to the third servo controlling means for moving the other second movable member end along the other vertical member.

A position control apparatus for controlling a position of a first moveable member in vertical and horizontal directions, the first moveable member being moveable on a second moveable member by a first driving means along a horizontal axis, the second moveable member having two ends engaged to two vertical members and vertically moveable by second and third driving means along the vertical members, the two ends of the second moveable member being supported by liquid pressure supporting means for cancelling weight associated with the first and second moveable members, the position control apparatus comprising:

• a first servo controlling means for controlling the position of the first moveable member on the second moveable member in response to a fist position control command, the first position control command for moving the first moveable member along the horizontal axis;
• a common position instructing means for outputting a second position control command;
• second and third servo controlling means for respectively controlling vertical positions of the two ends of the second moveable member along the two vertical members;
• a first vertical position correction means for calculating a first vertical position correction signal in response to the position of the first moveable member, the first vertical position correction signal and the second position control command being cooperatively applied to the second servo controlling means for moving one of the two second movable member ends along a corresponding one of the two vertical member;
• and
• a second vertical position correction means for calculating a second vertical position correction signal in response to the position of the first moveable member, the second vertical position correction signal and the second position control command being cooperatively applied to the third servo controlling means for moving the other second movable member end along the other vertical axis.

A position control system comprising:

• a first moveable member;
• a first driving means communicating with the first movable member and for moving the first movable member;
• a second moveable member, the first moveable member being slidably attached to the second movable member, the second moveable member having two ends;
• second and third driving means communicating with the second movable member and for moving the second movable member;
• the two ends of the second moveable member being supported by liquid pressure supporting means for cancelling weight associated with the first and second moveable members;
• the first moveable member being moveable on the second moveable member by the first driving means along a horizontal axis, the two ends of the second moveable member engaged to two vertical members and vertically moveable by the second and third driving means along the vertical members;
• and
• a position control apparatus for controlling a position of the first moveable member in vertical and horizontal directions, comprising:
• a first servo controlling means for controlling the position of the first moveable member on the second moveable member in response to a first position control command, the first position control command for moving the first moveable member along the horizontal axis;
• a common position instructing means for outputting a second position control command;
• second and third servo controlling means for respectively controlling vertical positions of the two ends of the second moveable member along the two vertical members;
• a first vertical position correction means for calculating a first vertical position correction signal in response to the position of the first moveable member, the first vertical position correction signal and the second position control command being cooperatively applied to the second servo controlling means for moving one of the two second movable member ends along a corresponding one of the two vertical members;
• and
• a second vertical position correction means for calculating a second vertical position correction signal in response to the position of the first moveable member, the second vertical position correction signal and the second position control command being cooperatively applied to the third servo controlling means for moving the other second movable member end along the other vertical member.

A method for controlling a position of a first moveable member in vertical and horizontal directions, the first moveable member being moveable on a second moveable member by a first driving means along a horizontal axis, the second moveable member having two ends engaged to two vertical members and vertically moveable by second and third driving means along the vertical members, the method comprising:

• generating a first position control command and controlling the position of the first moveable member on the second moveable member in response to the first position control command;
• generating a second position control command;
• calculating a first vertical position correction signal in response the position of the first moveable member;
• moving one of the two second moveable member ends along a corresponding one of the two vertical members in response to the first vertical position correction signal and the second position control command;
• calculating a second vertical position correction signal in response to the position of the first moveable member;
• and
• moving the other second movable member end along the other vertical members in response to the second vertical position correction signal and the second position control command.