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, Cartesian coordinate, multi-axis, and cylindrical coordinate types. Controllers typically use multi-CPU or multi-level computer systems for motion control and programming. End-effectors are designed into various grippers and wrists to accommodate different assembly objects. The sensor system is responsible for gathering 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, which emerged in 1978 as the ancestors of industrial robots, and the Selective Compliance Assembly Robot Arm (SCARA) robots. Compared to general industrial robots, assembly robots offer high precision, good compliance, a smaller working range, and compatibility with other systems, making them primarily used in the manufacturing of various electrical appliances.