Distinct interactions between electric drive and non-uniformly geared transmission
The four-unit crank gear is a basic kinematic structure that forms the basis of the kinematic structure of numerous mechanisms. Crank gears are used, for example, as a guide gear to guide a tool on a certain path or as a transmission gear to create a fixed connection between the drive position and the output position.
At IGMR, a test bench was developed for the investigation of a four-unit crank gear unit. The crank gear is driven by a synchronous servo motor. If the controller parameters of the servo amplifier are set in accordance with the manufacturer's instructions, there will be significant fluctuations in the course of the drive speed, which are due to the uneven load on the drive.
For the overall system of the test bench, a model was created in order to investigate the dynamic behaviour of this system in a purely virtual environment. In this step, it has already been determined which physical effects are to be taken into account and which properties can be described with the model. It should be noted that the model parameters introduced for the model description can be determined on the real system with sufficient accuracy, for example by calculation, measurement or tests.
Model-based analysis of the dynamic system
Ultimately, the task of modelling is to design the model as simple as possible and only as complex and extensive as necessary. Often, multi-body models can be simplified and abstracted even further by using equivalent replacement models for parts of the multi-body model reduced to rack axles. These strongly abstracted models are called vibration models.
Due to their high degree of abstraction, vibration models are particularly well suited for mathematical description and analysis by equations in symbolic form. The use of symbolic equations offers, for example, the possibility of analytically determining the relevance of individual parameters for the motion or stability behavior.