Regarding scaling behavior and possible simulation parameters
Posted: 24 Jan 2022, 11:54
Good day,
I have a question regarding some scaling behavior in Coppelia that I do not seem to properly understand. Before I can explain the issue, let me summarize my simulation setup:
I feed the system a randomized step pattern of forces as inputs, upon which the dynamic cube connected to the joint moves to certain positions as outputs. I measure these input/output pairs and estimate a transfer function based on the data.
Now, I expect my Coppelia setup to behave as a mass-damper system, i.e. mx’’ = F – cx’, where mass = 1, and c = 10, discretized with the same sampling rate as Coppelia. However, when applying the same force-inputs to this theoretical transfer function, the outputs have a similar shape but different size to the estimated system output (as can be seen in the figure below).
This leads me to believe the CoppeliaSim is performing some scaling that I am not aware about. This assumption is also strengthened by the fact that when I increase the linear damping factor c of my theoretical transfer function, I can indeed get a response similar to the simulation setup (as can be seen in the figure below).
Main question:
Am I missing something from the CoppeliaSim setup? Are some values scaled that I do not know about? I really could use some help with this part, as it is difficult for me to retrieve this information from the documentation.
Kind regards,
Daniel
I have a question regarding some scaling behavior in Coppelia that I do not seem to properly understand. Before I can explain the issue, let me summarize my simulation setup:
- Large static surface with c = 10 linear damping factor
- Two cubes resting on top of it, connected with a prismatic joint
- Of those two cubes, one static cube serves as the base, the other dynamic cube (c = 10 linear damping factor, mass = 1kg) moves across the joint with respect to the base
I feed the system a randomized step pattern of forces as inputs, upon which the dynamic cube connected to the joint moves to certain positions as outputs. I measure these input/output pairs and estimate a transfer function based on the data.
Now, I expect my Coppelia setup to behave as a mass-damper system, i.e. mx’’ = F – cx’, where mass = 1, and c = 10, discretized with the same sampling rate as Coppelia. However, when applying the same force-inputs to this theoretical transfer function, the outputs have a similar shape but different size to the estimated system output (as can be seen in the figure below).
This leads me to believe the CoppeliaSim is performing some scaling that I am not aware about. This assumption is also strengthened by the fact that when I increase the linear damping factor c of my theoretical transfer function, I can indeed get a response similar to the simulation setup (as can be seen in the figure below).
Main question:
Am I missing something from the CoppeliaSim setup? Are some values scaled that I do not know about? I really could use some help with this part, as it is difficult for me to retrieve this information from the documentation.
Kind regards,
Daniel