In this thesis we analyzed stepper motors with emphasys on hybrid stepper motors. First we examined basic structure and basic properties of stepper motors. Then we analyzed basic dynamic properties of stepper motor and built a mathematical model of hybrid stepper motor. Before using the model to simulate our stepper motor, we had to experimentally determine some of its parameters, i.e. the viscous damping coefficient and the torque constant of our stepper motor.
Using our model, we conducted different experiments and then compared the results of our experiments with the results of measurements. Especially we were interested in Pull–out torque characteristic, because it tells us how big of a load the stepper motor can drive at certain speed.
Results of our simulation have shown, that our model works and reacts as a stepper motor should. With simulation we also acquired torque – speed characteristic. The shape of simulated characteristics is in accordance with theory, at low speed we have two ressonance frequencies, the torque then rises with motor speed and at some point starts to fall again. We compare our simulated characteristics with measured characteristics of a real stepper motor, but unfortunately simulated characteristics doesnt match measured characteristics. In the end we are very pleased with our stepper motor model and we will certainly use it for a simulation of a bigger more complex system that uses stepper motor for porpultion.
|
