Watch outer case polishing apparatus and general purpose polishing apparatus

A polishing apparatus comprising:

• a polishing member for polishing a workpiece, the polishing member and the workpiece defining therebetween a contact surface having a contact surface coordinate system relative to an initial coordinate system defined when the polishing member and the workpiece initially contact one another at the contact surface but before a force is exerted on the contact surface to polish the workpiece;
• a manipulator having at least one moving element having driving portions for manipulating the workpiece to polish the workpiece, the manipulator having a base disposed at a coordinate origin of a base coordinate system;
• first control means for successively updating a position and attitude of the contact surface coordinate system with respect to the initial coordinate system on the basis of a deviation between preselected values of force and moment acting on the workpiece and detected values of force and moment acting at the contact surface between the polishing member and the workpiece when a force is exerted on the contact surface to polish the workpiece;
• second control means for successively updating a position and attitude of the contact surface coordinate system with respect to a coordinate system corresponding to the workpiece by changing a position and attitude of the workpiece;
• calculating means for calculating a position and attitude of the manipulator on the basis of the updated results of the first and second control means and a position and attitude of the initial coordinate system with respect to the base coordinate system;
• and
• driving means for driving the driving portions of the moving element of the manipulator to manipulate the workpiece on the basis of the calculation results of the calculating means.

A method of polishing a workpiece, comprising the steps of:

• providing a polishing member for polishing a workpiece, the polishing member and the workpiece defining therebetween a contact surface having a contact surface coordinate system relative to an initial coordinate system defined when the polishing member and the workpiece initially contact one another at the contact surface but before a force is exerted on the contact surface to polish the workpiece;
• providing a manipulator having driving portions for manipulating the polishing member or the workpiece, the manipulator having a base disposed at a coordinate origin of a base coordinate system;
• driving the driving portions of the manipulator to polish the workpiece;
• successively updating a position and attitude of the contact surface coordinate system with respect to the initial coordinate system on the basis of a deviation between preselected values of force and moment acting on the polishing member or the workpiece and detected values of force and moment acting at the contact surface between the polishing member and the workpiece when a force is exerted on the contact surface during polishing of the workpiece;
• successively updating a position and attitude of the contact surface coordinate system with respect to a coordinate system corresponding to the polishing member or the workpiece by changing a position and attitude of the polishing member or the workpiece, respectively;
• calculating a position and attitude of the manipulator on the basis of the updated results of the first and second control means and a position and attitude of the initial coordinate system with respect to the base coordinate system;
• and
• driving the driving portions of the manipulator to manipulate the polishing element or the workpiece to polish the workpiece on the basis of the calculation results of the calculating means.