Compliance device and working robot including the same

A working robot comprising:

• a robot arm;
• a compliance device mounted to an end of the robot arm;
• and
• a work tool connected to the compliance device and configured to hold a workpiece,
• wherein the compliance device comprises:
• a fixed platform in which a fixed origin of a fixed coordinate system having 3 axes of X-Y-Z is defined;
• a moving platform which is configured to move relative to the fixed platform and in which a moving origin of a moving coordinate system having 3 axes of x-y-z is defined;
• a compliance mechanism comprising a plurality of unit compliance mechanisms configured to elastically support the moving platform against the fixed platform, each of the plurality of unit compliance mechanisms comprising a cantilever structure, which comprises a first end fixed to the fixed platform and a second end opposite to the first end, and a link, which is coupled to the second end of the cantilever structure via a first ball joint and coupled to the moving platform via a second ball joint;
• a linear actuator mounted on the moving platform and configured to move the work tool in a Z-axis direction;
• a moving plate connected to the linear actuator and configured to be moved in the Z-axis direction by the linear actuator;
• and
• a rotary actuator mounted on the moving plate and configured to rotate the work tool about an axis parallel to the Z-axis direction.

A compliance device comprising:

• a fixed platform in which a fixed origin of a fixed coordinate system having 3 axes of X-Y-Z is defined;
• a moving platform which is configured to move relative to the fixed platform and in which a moving origin of a moving coordinate system having 3 axes of x-y-z is defined;
• a compliance mechanism comprising a plurality of unit compliance mechanisms configured to elastically support the moving platform against the fixed platform, each of the plurality of unit compliance mechanisms comprising a cantilever structure, which comprises a first end fixed to the fixed platform and a second end on the opposite side from the first end, and a link, which is coupled to the second end of the cantilever structure via a first ball joint and coupled to the moving platform via a second ball joint;
• a linear actuator mounted on the moving platform and configured to move a work tool in a Z-axis direction;
• a moving plate connected to the linear actuator and configured to be moved in the Z-axis direction by the linear actuator;
• a rotary actuator mounted on the moving plate and configured to rotate the work tool about a Z-axis;
• a force/moment sensor which comprises unit sensors configured to sense amounts of elastic deformation of the plurality of unit compliance mechanisms, and is configured to detect a force in an X-axis direction, a force in a Y-axis direction, a moment about an X-axis as a rotation central axis, and a moment about a Y-axis as a rotation central axis which act on the moving origin of the moving platform;
• a double universal joint which is located between the fixed platform and the moving platform and configured to limit rotation of the moving platform about the Z-axis;
• and
• a gravity compensation mechanism that comprises a first spring support coupled to the moving platform, a second spring support coupled to the fixed platform, and a tension spring connected to the first spring support and the second spring support,
• wherein each of the plurality of unit compliance mechanisms is configured such that a straight-line distance between the first ball joint and the second ball joint is variable.