Analysis of the cause of inaccurate positioning during the adjustment of the stepper motor - News - Global IC Trade Starts Here Free

During the tuning process, it was observed that the stepping motor positioning error is typically caused by several factors:

1. Pulse loss occurs when changing direction. The motor operates accurately in one direction but accumulates deviation when the direction changes, with the error increasing as the number of direction changes increases.

2. If the initial speed is too high or the acceleration is too abrupt, it can lead to missed steps, especially under heavy load conditions.

3. When using a timing belt, excessive or insufficient software compensation may cause misalignment during direction changes due to the elasticity of the belt.

4. Insufficient motor power can result in inaccurate positioning, especially under dynamic loads.

5. System-level interference can cause the controller or driver to malfunction, leading to erratic behavior.

6. Electrical noise from the driver can also contribute to positioning errors.

7. Software bugs or design flaws might introduce unexpected issues during operation.

Here’s an analysis of each issue and possible solutions:

1) Stepper drivers usually require precise timing between the direction signal and pulse input. If the direction signal arrives too late or too early relative to the pulse edge, the motor may rotate in the wrong direction, causing cumulative error. This is more noticeable at higher subdivisions. A common fix is to adjust the pulse logic or add a small delay in the software.

2) Stepping motors have limited acceleration capabilities. Starting at too high a speed, especially with large inertia, can cause missed steps. It's recommended to start at a low speed (under 1r/s) and allow for a short pause between forward and reverse movements to prevent overshoot and improve accuracy.

3) Adjusting the compensation parameters based on actual performance can help. For example, when using a flexible timing belt, directional changes may require additional compensation to account for the belt's elasticity.

4) Increasing the motor current or the driver voltage (if supported) can improve torque and reduce positioning errors. Consider using a motor with higher torque if necessary.

5) To address interference issues, identify and isolate the source of noise. Common methods include shielding cables, separating signal wires from high-current lines, and using filters. Improving the system’s immunity to interference is crucial for stable operation.

1) Replace standard wiring with double-shielded cables to minimize electromagnetic interference. Keep signal wires away from high-power lines where possible.

2) Use power line filters to remove noise from the power supply. Adding filters at the input of large equipment can reduce cross-interference between components.

3) Opt for optical isolation for signal transmission between devices. Differential signaling combined with photoelectric isolation is ideal for pulse and direction signals. For inductive loads like relays or solenoids, use RC snubbers or fast bleeders to suppress voltage spikes, especially when operating above 20kHz.

6) Implement fault-tolerant features in the software to handle minor interferences and ensure smooth operation.