A robot system according to one or more embodiments may include a robot, and a control part. The robot may include one or more joints driven by an electric motor, and can hold a wafer by a holding part. The control part gives commands to the robot for control. When the robot holds and transports the wafer with the holding part, the control part performs, based on information about the electric motor, at least one of the following: determining whether slippage has occurred between the holding part and the wafer; and estimating an amount of slippage of the wafer relative to the holding part.

A robot system according to one or more embodiments may include a robot, and a control part. The robot may include one or more joints driven by an electric motor, and can hold a wafer by a holding part. The control part gives commands to the robot for control. When the robot holds and transports the wafer with the holding part, the control part performs, based on information about the electric motor, at least one of the following: determining whether slippage has occurred between the holding part and the wafer; and estimating an amount of slippage of the wafer relative to the holding part.

An electrical drive system includes a motor, a load device and a coupling unit, wherein a slip is calculated by comparing signals between a motor sensor and a load sensor, and a motor sensor-based position of the load device is cyclically updated, provided that a slip remains below a slip threshold value.

An electrical drive system includes a motor, a load device and a coupling unit, wherein a slip is calculated by comparing signals between a motor sensor and a load sensor, and a motor sensor-based position of the load device is cyclically updated, provided that a slip remains below a slip threshold value.