AC permanent magnet synchronous servo motors are the most common drive motor for robot joint control. Stepper motors and brushless DC motors are also widely used. Direct drive torque motors are mainly used in high-precision special applications.
1. AC permanent magnet synchronous servo motor
This is the standard choice for industrial robot joints. It has high torque density and fast dynamic response. Positioning accuracy can reach within ±0.01°. It runs smoothly at low speed without vibration. With a joint reducer, it supports heavy-load, high-precision continuous work. Most 6-axis industrial arms use this type of motor at every joint.
2. Stepper motor
Stepper motors fall into open-loop and closed-loop types. Open-loop steppers cost less but can lose steps. Closed-loop steppers use encoder feedback to solve this. They offer good value for light-load, low-speed small robots, such as educational programming robots and low-load joints on desktop collaborative robots.
3. Brushless DC motor
Brushless DC motors need no carbon brush maintenance. They have stable torque characteristics and low noise. Some lightweight collaborative robots and mobile manipulators use them in joints. With a harmonic reducer, they can meet medium-precision work requirements.
4. Direct drive torque motor (DD motor)
A DD motor drives the joint directly without an extra reducer. It offers very high positioning accuracy. It is mainly used in special applications with extreme precision requirements, such as precision assembly and medical surgical robot joints. Cost is higher, so it is less common.
For robot joint manufacturers, Hansheng Automation machines motor housings, rotor parts, harmonic reducer components, and other precision joint parts from customer drawings. Single-piece and small-batch orders are supported.
