Examination of the resonance properties of a servosystem, attenuation of resonancy frequency with usage of biquad filter.

OData support
Janka Sándor
Department of Electric Power Engineering

Nowadays controlling a motion control system gets easier as the technology of digital drives advance. The drive used to be a simple analog circuit compared to the complex system it is now. It tends to take over more and more of the functions that used to be the sole domain of the controller. Because of this, functioning a motion control system doesn't even necessarily need a skilled engineer. In the meantime they want the system to operate at it's most optimal way. This sometimes gets restricted by the problems of a compliantly coupled load, which causes mechanical resonance. This is a real problem which was either simply neglected and the control loops were made weaker in order to avoid stability problems caused by the resonance, or they had to use different mechanical elements in the motion control system, eg. a stronger motor or more rigid coupling. However with the modern digital drive there is an electronic cure for resonance. With the help of a filter you could get rid of the resonance problem, for this you only need to know the frequencies and the magnitudes of resonance.

In my thesis I was working with an AMC digital drive to documentate and solve the problem. I created an environment for a compliantly coupled motion control system, where I could measure the response of the system with the help of a built in oscillator. With the use of Matlab I could determine the parameters of a built in digital biquadratic filter in order to oppress the mechanical resonance. The filter was then placed in the correct position of the control loop. The result was success, with the mechanical resonance almost gone and the performance of the servo increased.


Please sign in to download the files of this thesis.