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The solution of displacement phenomenon produced by stepping

时间:2010-03-10 08:31

  Stepper motor is a kind of induction motor, its working principle is the use of electronic circuit, the DC power supply variable components, multi-phase timing control current this current stepper motor power supply, stepper motor can work normally, power supply for the stepper motor driver is divided into the multi-phase sequence controller.

  An open-loop control element of stepping motor that transforms an electric impulse signal into angular displacement or linear displacement. In the case of non-overloaded, the motor speed and stop position depends only on the pulse frequency and pulse number, regardless of load changes, when the stepper driver receives a pulse signal, it drives stepper motor to set the direction of rotation of a fixed angle, called "step", it is the rotation of the fixed point of the operation step by step. Number of pulses can be controlled by controlling the angular displacement, so as to achieve the purpose of accurate positioning; at the same time by controlling the pulse frequency to control the motor rotation speed and acceleration, so as to achieve the purpose of speed.

一、When changing the direction, the pulse is lost, which is shown to be correct in any direction, but when one changes direction, the cumulative deviation is increased;

二、The initial speed is too high, acceleration is too large, causing sometimes lost step;

三、In the case of synchronous belt, software compensation too much or too little;

四、Motor power is not enough;

五、The controller is disturbed, causing misoperation;

六、Drive caused by interference;

七、Software defects;

There are several ways to solve the problem:    

1)General stepper motor driver has certain requirements, such as: the direction and direction of the signal pulse signal in the first pulse rising edge or falling edge (different drive requirements are not the same) before the arrival of microseconds is determined, otherwise there will be a pulse steering angle of the running contrary to the actual needs of the performance. Finally, the fault phenomenon as the farther side, the smaller the more obvious segmentation, the solution changes the pulse logic or delay mainly by software.

2)Because the stepper motor characteristics determine the initial velocity is not too high, especially with the initial velocity of load under 1r/s suggested that under the condition of large inertia, so the impact is small, the same acceleration also too big impact on the system, easy to overshoot, resulting in inaccurate positioning between the motor forward and reverse, there should be a certain time if there will be suspended because of too large overshoot caused by negative acceleration.

3)Adjust the value of the compensated parameter according to the actual situation (because the elastic deformation of the synchronous belt is larger, so it needs a certain compensation when changing the direction).

4)Increase the motor current properly, increase the drive voltage (pay attention to matching motor drives), select motors with greater torque.

5)System interference caused by misoperation or drive controller, we can only think of a way to find out the source of interference, reduce the disturbance (such as shielding, increase distance etc.), cut off the route of transmission, improve the ability of anti-jamming, common measures:

①Double line shielded wire is used instead of ordinary wire, and the line of the system is separated from the big current or big voltage change wire to reduce the electromagnetic interference.

②Filter the interference wave from the power grid with the power filter, and add the power filter to the input terminals of each large power equipment under the condition permit, so as to reduce the interference between the equipment in the system.

③The photoelectric isolation device is best used for signal transmission between the equipment. Under the conditions permit, the pulse and directional signal should be transmitted by photoelectric isolation in differential mode. In the inductive load (such as electromagnetic relay, electromagnetic valve) at both ends of the resistance to capacitive absorption or rapid discharge circuit, inductive load at the beginning of the instant can produce 10~100 times the peak voltage, if the work frequency is above 20KHZ.

6)Software does some fault tolerant processing, which interferes with the elimination of interference.