Robot system, controller and control method

A controller comprising:

• vibration detection circuitry configured to detect vibration of a workpiece in a vibration direction;
• estimation circuitry configured to estimate an arrival timing at which the workpiece arrives at a return position in the vibration direction based on the vibration detected by the vibration detection circuitry, the arrival timing being estimated at a moment when the vibration of the workpiece in the vibration direction has a displacement speed of zero;
• and
• control circuitry configured to control an arm of a robot based on the arrival timing such that a tool connected to the arm performs work on a target portion of the workpiece.

A control method comprising:

• detecting vibration of a workpiece in a vibration direction;
• estimating an arrival timing at which the workpiece arrives at a return position in the vibration direction based on the detected vibration, the arrival timing being estimated at a moment when the vibration of the workpiece in the vibration direction has a displacement speed of zero;
• and
• controlling an arm of a robot based on the arrival timing such that a tool connected to the arm performs work on a target portion of the workpiece.