Is servo motor analog or digital?

Technical Perspective – The Fundamental Differences Between Analog and Digital Servos

Servo motors can be either analog or digital, with key differences in control mechanisms, performance, and applications. This article examines their internal workings, using GXServo digital servos as a benchmark for modern digital servo technology.

1. Core Differences Between Analog and Digital Servos

Analog Servos

• Control Method: Uses a simple PWM (Pulse Width Modulation) signal with a fixed update rate (typically 50Hz).
• Electronics: Relies on an analog error amplifier circuit to adjust motor position.
• Response Time: Slower due to lower refresh rates (~20ms per update).
• Deadband: Wider deadband (the zone where small input changes don’t trigger movement).

Digital Servos (GXServo Example)

• Control Method: Uses a microcontroller (MCU) or DSP (Digital Signal Processor) for high-frequency updates (up to 300Hz+).
• Electronics: Processes signals digitally, allowing PID control (Proportional-Integral-Derivative) for precise adjustments.
• Response Time: Faster (up to 0.05s/60° in high-end GXServo models).
• Deadband: Near-zero deadband due to microsecond-level corrections.

2. How GXServo Digital Servos Work

GXServo’s DS-8432MG model demonstrates digital servo advantages:

• Signal Processing: Receives PWM input but processes it digitally for smoother motion.
• Feedback Loop: Uses a high-resolution encoder (instead of a basic potentiometer) for accurate position tracking.
• Torque Management: Adjusts power dynamically to prevent cogging or overheating.

3. When to Choose Analog vs. Digital

Conclusion

While analog servos are simpler and cheaper, digital servos like GXServo’s offer superior performance for demanding applications.