Robot motor drives are the power mechanisms that enable robots to perform movements. These drives can convert electrical energy, hydraulic energy, and pneumatic energy into the power required by robots. They include DC servo motors, stepper motors, and AC servo motors. The commonly used robot motor drives are as follows:

1. DC Servo Motor Drives:

DC drives mostly use PWM (Pulse Width Modulation) servo drives. By changing the pulse width, the average voltage applied to the motor armature terminals is altered, thereby changing the motor speed. PWM servo drives have characteristics such as a wide speed range, good low-speed performance, fast response, and strong overload capacity. They are commonly used as DC servo motor drives in industrial robots.

2. Synchronous AC Servo Motor Drives:

Compared with DC servo motor drives, synchronous AC servo motor drives have advantages such as a high torque-to-inertia ratio, no brushes or commutation sparks, and are widely used in industrial robots. Synchronous AC servo motor drives typically use a current-type PWM inverter and a multi-loop control system with a current loop as the inner loop and a speed loop as the outer loop to enhance the current control of three-phase permanent magnet synchronous servo motors. Depending on their working principles, drive current waveforms, and control methods, they can be divided into two types of servo systems:

a. Permanent magnet AC servo systems driven by rectangular wave current.
b. Permanent magnet AC servo systems driven by sinusoidal wave current.

Permanent magnet AC servo motors driven by rectangular wave current are called brushless DC servo motors, while those driven by sinusoidal wave current are called brushless AC servo motors.

3. Stepper Motor Drives:

Stepper motors are components that convert electrical pulse signals into corresponding angular or linear displacements. Their angular and linear displacements are proportional to the number of pulses. The speed or linear velocity is proportional to the pulse frequency. Within the load capacity range, these relationships do not change due to fluctuations in supply voltage, load size, or environmental conditions. Errors do not accumulate over time. Stepper motor drive systems can adjust speed over a wide range by changing the pulse frequency, enhancing rapid start-up and reversible braking.