As a core component in modern industrial automation systems, the performance of a servo drive directly affects the equipment's operational accuracy and stability. This article systematically explains the debugging process, key technical points, and common problem-solving methods for servo drives to help engineers quickly master debugging techniques.
1. Hardware Inspection
Confirm that the motor model matches the drive (e.g., rated power, voltage, encoder type).
Ensure the power cables (U/V/W) and encoder cables are securely connected to avoid phase sequence errors.
Grounding resistance should be less than 4Ω. Keep high-power and low-power wiring separate.
2. Parameter Pre-Setting
Input basic parameters according to the motor nameplate: rated current, speed, encoder resolution.
Select the control mode (position/speed/torque). Speed mode is typically chosen for initial debugging.
Set the electronic gear ratio (Reference formula: Electronic Gear Ratio = Encoder Resolution × Mechanical Reduction Ratio / Pulses Per Revolution).
1. Inertia Identification
Perform auto-tuning under no-load conditions. The drive will automatically calculate the motor rotor inertia.
For high-precision applications, perform a secondary identification with the load attached (ensure mechanical limits are removed).
Typical adjustment parameters: Speed loop gain (Kv), integral time (Ti), filter cutoff frequency.
2. PID Parameter Tuning
Proportional Gain (P): Gradually increase from a low value until slight system oscillation occurs, then reduce by 20%.
Integral Time (I): Eliminates steady-state error. Too long a time leads to sluggish response.
Derivative Time (D): Improves dynamic response. Excessive values introduce noise.
Recommended Tool: Use the step response curve to observe overshoot (recommended to control within 5%).
3. Rigidity Adjustment
Adjust the mechanical rigidity coefficient (0-100%) to balance response speed and vibration.
Typical Cases:
• Machine tool feed system: Set rigidity to 70-85%.
• Robot joint: Set rigidity to 40-60%.
After enabling vibration suppression function, re-optimize notch filter parameters.
1. Full Closed-Loop Control Implementation
When using an external linear scale, set the position feedback division ratio.
Pay attention to master/slave encoder sampling synchronization in dual-loop systems.
Typical application: Semiconductor equipment positioning accuracy can reach ±1μm.
2. Safety Function Testing
Verify STO (Safe Torque Off) functionality.
Test dynamic braking resistor operating current.
Set overload protection threshold (recommended at 150% of rated current).
|
Fault Phenomenon |
Possible Causes |
Solution |
|
Motor Jitter |
Overly aggressive PID parameters / Mechanical resonance |
Reduce rigidity / Enable vibration suppression function |
|
Positioning Error |
Incorrect electronic gear ratio / Backlash |
Recalculate transmission ratio / Compensate for mechanical clearance |
|
Overload Alarm |
Sudden load change / Poor heat dissipation |
Check for mechanical binding / Clean cooling air ducts |
|
Encoder Anomaly |
Cable interference / Unstable power supply |
Use twisted-pair shielded cables / Install ferrite cores |
1. Oscilloscope Function Usage
When capturing speed/current waveforms, a sampling rate ≥ 10kHz is recommended.
Analyze positioning error by synchronously displaying the command position and actual position curves.
2. Parameter Batch Management
Use the drive manufacturer's software to export parameter templates (e.g., .bin or .csv format).
For debugging multiple devices, use the parameter cloning function to save time.
3. Cloud Monitoring Implementation
Connect to Industrial IoT platforms via Modbus TCP protocol.
Monitor key parameters in real-time: winding temperature, peak current, cumulative operating time.
1. CNC Machine Tools
Focus on optimizing feedforward control parameters (acceleration feedforward, speed feedforward).
For C-axis indexing positioning, adjust the origin search speed (recommended ≤ 30 rpm).
2. Packaging Machinery
When using electronic cam function, precisely set the phase relationship between the master and slave axes.
For color mark synchronization compensation, using a high-speed DI capture function is recommended.
3. Robot Joints
Compensate for gravity torque parameters (pay special attention to axes 4-6 in a 6-axis robot).
Friction compensation coefficients are recommended to be set in segments (low-speed zone / high-speed zone).
(1) Regularly check the condition of electrolytic capacitors (recommend replacement after 5 years of use).
(2) Clean heat sink dust quarterly (be alert if temperature rise exceeds 10°C).
(3) Record the firmware version number when backing up parameters (to avoid compatibility issues after upgrades).
A systematic debugging process enables the servo system to achieve optimal operating. In practical applications, adjustments should be made flexibly based on specific mechanical characteristics. It is recommended to save parameter sets for different operating conditions to enable quick switching. For complex systems, self-tuning algorithms (such as fuzzy PID, adaptive control) can be adopted to further enhance dynamic performance.
