Application of servo in industrial robot technology

Chi Yonglin, operations manager of ABB Precision Assembly Center, said: "In all application fields, the penetration rate of industrial robots is less than 12%, and the market demand potential is huge, especially in the Chinese market. As manufacturing costs increase and the demographic dividend begins to fade, the demand for robots to replace labor will increase, which will drive the upgrading of the entire manufacturing equipment and technology."

The growth of the robot industry is in full swing, and a large number of machine tool manufacturers, servo manufacturers and other qualified enterprises have turned to the robot market. Why are machine tool manufacturers and servo manufacturers so actively transforming and developing robots? Industrial robots have four major components, namely the body, servo, reducer and controller. Among them, servo and controller are what machine tool manufacturers are good at, so a large number of machine tool manufacturers choose robots as the direction of product transformation and upgrading. The control system and automation products of industrial robots mainly involve servo motors, reducers, controllers and sensors. The servo motor can be divided into two major parts, one is the motor body and the other is the motion control system.

Motor

The motor is used to drive the joints of the robot, and the requirements are to have a maximum power-to-mass ratio and torque-to-inertia ratio, high starting torque, low inertia and a wide and smooth speed regulation range. In particular, the end effector (gripper) of the robot should use a motor with the smallest possible volume and mass. Especially when fast response is required, the servo motor must have high reliability and large short-term overload capacity.

At present, AC and DC servo motors with high starting torque, large torque and low inertia are widely used in industrial robots.

Servo control system

is an automatic control system that uses mechanical position or angle as the control object, such as CNC machine tools, robots, etc. The drive motor used in the servo system is required to have fast response speed, accurate positioning, and large moment of inertia (the moment of inertia of the servo motor used in the electromechanical system). In order to be directly connected to mechanical parts such as the lead screw, the servo motor has a special small inertia motor in order to obtain extremely high response speed. However, this type of motor has low overload capacity, and when used in a feed servo system, a deceleration device must be added. The

general structure of the electric servo system of an industrial robot is three closed-loop controls, namely the current loop, the speed loop and the position loop. In general, for an AC servo drive, multiple functions such as position control, speed control, and torque control can be achieved by manually setting its internal function parameters.