Assembly robots are the core equipment of flexible automation assembly systems, consisting of robot arms, controllers, end-effectors, and sensor systems. The robot arms come in various structural types, such as horizontal joint, right-angle coordinate, multi-joint, and cylindrical coordinate types. Controllers typically use multi-CPU or multi-level computer systems to achieve motion control and programming. End-effectors are designed into various grippers and wrists to accommodate different assembly objects. The sensor system collects information on the interaction between the assembly robot, the environment, and the assembly objects. Common assembly robots include the Programmable Universal Manipulator for Assembly (PUMA) robots (introduced in 1978, the ancestor of industrial robots) and the Selective Compliance Assembly Robot Arm (SCARA) robots. Compared to general industrial robots, assembly robots feature high precision, good compliance, a smaller working range, and the ability to be integrated with other systems, making them primarily used in the manufacturing of various electrical appliances.