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 typically arises from several key factors:

1. Pulse loss occurs when changing direction. The motor operates accurately in one direction, but as soon as the direction is reversed, a cumulative deviation appears, 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 cause step loss, leading to inaccurate positioning.

3. When using a timing belt, overcompensation or under-compensation in the software can lead to positioning errors, especially due to the elastic deformation of the belt.

4. Insufficient motor power may result in inadequate torque, causing the motor to fail to reach the desired position.

5. System-level interference can disrupt the controller or driver, leading to malfunctions.

6. Electrical noise or interference in the driver circuit can also affect the performance of the motor.

7. Software bugs or flaws in the control logic might contribute to inconsistent behavior and positioning issues.

Here’s an analysis of these problems:

1) Stepper drivers usually require precise timing between the direction signal and the pulse signal. If the direction signal arrives too late or too early relative to the pulse edge, the motor may move in the opposite direction, leading to accumulated errors. This issue becomes more pronounced at lower subdivisions. To resolve this, adjusting the pulse logic or adding a small delay can help improve accuracy.

2) Due to the nature of stepper motors, starting at too high a speed or accelerating too quickly can cause the motor to lose steps, especially when there's significant load inertia. It's recommended to start at a speed below 1 revolution per second to minimize impact. Also, ensuring a short pause between forward and reverse movements helps prevent overshoot caused by rapid acceleration.

3) Adjusting the compensation parameters based on real-world conditions is essential, particularly when using flexible components like timing belts. Proper compensation ensures smoother directional transitions and reduces positional errors.

4) Increasing the motor current or raising the driver voltage (as supported by the driver) can improve torque and reduce the likelihood of missed steps. Choosing a motor with higher torque can also be beneficial in demanding applications.

5) Electromagnetic interference (EMI) can cause the controller or driver to malfunction. To mitigate this, identify and eliminate the source of interference, such as by shielding cables, increasing separation distances, or improving grounding. Common solutions include:

1) Replacing standard wires with double-shielded cables and separating signal lines from high-current or high-voltage lines to reduce EMI.

2) Using power filters to clean up the power supply, especially for large equipment. Adding filters at the input of each major device can reduce internal system interference.

3) Implementing optical isolation for signal transmission between devices. For better reliability, use differential signaling combined with photoelectric isolation. For inductive loads like relays or solenoids, adding RC snubbers or fast bleeders can suppress voltage spikes, especially when operating above 20kHz.

6) Implementing fault-tolerant mechanisms in the software can help detect and correct for interference, ensuring more stable and accurate motor operation.