Apparatus and method for optimizing swap time

A method of transporting workpieces with a robotic apparatus, comprising:

• providing a robotic apparatus having:
• an arm member configured to pivot about a first axis;
• a first end effector pivotably connected to the arm member about a second axis, the first end effector having a first surface upon which a first workpiece can be received;
• a second end effector pivotably connected to the arm member about the second axis, the second end effector having a second surface upon which a second workpiece can be received;
• at least one drive unit configured to drive the arm member to pivot about the first axis, the at least one drive unit being configured to drive the first end effector to pivot about the second axis, the at least one drive unit being configured to drive the second end effector to pivot about the second axis;
• and
• a control unit configured to control the at least one drive unit to move the arm member, the first end effector and the second end effector;
• and
• controlling the at least one drive unit to move the arm member, the first end effector and the second end effector to perform a swapping operation that includes the first end effector and the second end effector swapping arc positions disposed at opposite ends of an arc having a constant radius of curvature,
• wherein the at least one drive unit is controlled to move the arm member, the first end effector and the second end effector such that the first workpiece received on the first end effector and the second workpiece received on the second end effector each travel at equal and constant velocities along the arc.