The welding robot mainly includes two parts: robot and welding Equipment. The robot consists of a robot body and a control cabinet (hardware and software). Welding equipment, arc welding and spot welding as an example, by the welding power supply, (including its control system), wire feeder (ARC welding), welding Torch (pliers) and other Components. There should be a sensor system for intelligent robot, such as laser or camera sensor and its control device.

Figure 1a, B represents the basic composition of arc welding robot and spot welding Robot. Welding robots produced in countries around the world are mostly articulated robots, most of which have 6 axes. Among them, the 1, 2, 3 axes can send the end tool to different spatial positions, while the 4, 5, 6 axes resolve the different requirements of the tool Posture. The mechanical structure of the welding robot body has two main forms: a parallelogram structure and a side-mounted (tilting) structure, as shown in Figure 2a and B. The main advantage of the side-mounted (tilting) structure is that the upper and lower arms have a large range of activities, so that the robot can reach almost one sphere in its working space. As a result, the robot can work upside down on the rack to save floor space and facilitate the flow of objects on the Ground. But this side-mounted robot, the 2-and 3-axis cantilever structure, reduces the stiffness of the robot, generally suitable for small-load robots for Arc welding, cutting or Spraying. The parallelogram Robot's upper arm is driven by a lever. The lever and the lower arm form a parallelogram of two sides. Hence the Name. The early development of the parallelogram robot working space is relatively small (confined to the front of the robot), difficult to hang upside down Work. however, the new type of parallelogram robot (parallel Robot) developed since the late 80 has been able to extend the working space to the top, back and bottom of the robot, without the stiffness problem of the robot, thus getting a general Attention. This structure is not only suitable for lightweight but also for heavy machine people.

In recent years, the robot for spot welding (load 100~150kg) mostly chooses the parallelogram structure form Robot. The two kinds of robot axes are used for rotary motion, so the servo motor is driven by cycloid (RV) reducer (axis) and harmonic reducer (1~6 axis). Before the middle of the 80, for Electric-driven robots are DC servo motor, and since the late 80, countries have switched to AC servo MOTOR. Since the AC motor does not have a carbon brush, the dynamic characteristics are good, so that the new robot not only the accident rate is low, and maintenance-free time greatly increased, plus (minus) speed is also Fast. Some of the new light-duty robots under 16kg have the highest movement speed of the tool center point (TCP) up to 3m/s, accurate positioning and small vibration.

At the same time, the control cabinet of the robot is switched to 32-bit microcomputer and new algorithm, which has the function of optimizing the path, and the running trajectory is closer to the teaching trajectory.