METHODS FOR DETERMINING LOSING STEPS OF A STEPPER MOTOR

Ulyashev Artyom E., Startsev Andrey E.

When using stepper motors, the problem of skipping steps can occur. The essence of this problem is that when the control system sets the number of steps, for some reason the motor takes fewer steps. There are several reasons for this problem: driver failure in the motor control system, incorrectly set current in the motor phases, insufficient voltage in the motor windings, excessive load on the stepper motor shaft, high acceleration of the shaft, as well as the problem in the mechanical part - failure of gear or belt transmission. To solve this problem, angle sensors are used, which can detect a skipped step. The use of sensors with their control system increases the cost of the drive, as well as require additional space for their location. The task of the presented research is to determine the ways of skipping steps based on electric sensors, which are available to directly measure the coordinates of the stepper motor, through the use of its mathematical model. To solve the problem we used methods of mathematical modeling and experimental research. With the help of the mathematical model the equations were obtained, from which it is possible to judge the dynamics of the mechanical coordinates of the motor. As investigated parameters were considered the current in stator windings and the counter EMF generated during rotation of the rotor, which acts as a permanent magnet. The result of the study is the determination of parameters, which allow to register with a high degree of probability the skipping of steps by the motor.

Keywords:stepper motor, mathematical model, step loss