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Repository for the DRC project.
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Atlas model: Issue with the torque limits #361

Open osrf-migration opened 11 years ago

osrf-migration commented 11 years ago

Original report (archived issue) by Sylvain Bertrand (Bitbucket: SylvainBertrand).

I think there are some errors concerning the torque limits for the Atlas model. For example, the knee max torque is 220Nm while the ankle pitch max torque is 700Nm, which sounds lowly probable. Also the arm joint max torques are higher than the ones published by Boston Dynamics. For example, the shoulder pitch max torque is 212Nm in the simulation model, while BDI gives a min torque of -75Nm and a max torque of 93Nm.

It'd be awesome if you could check the different joint maximum torques.

Regards, Sylvain

osrf-migration commented 10 years ago

Original comment by Brian Gerkey (Bitbucket: Brian Gerkey, GitHub: gerkey).

The limits included in the simulation model are taken directly from the data provided to us by BDI. For example, the maximum knee pitch torque is given as 220Nm and the maximum ankle pitch torque is given as 700Nm.

I agree that those values seem improbable, but we don't have any newer or more accurate information about the torque limits. We'd happily accept patches to improve the model.

osrf-migration commented 10 years ago

Original comment by Steven Gray (Bitbucket: stgray).

The torque limits change depending on the current joint angle. Is there a way to handle this in gazebo?

osrf-migration commented 10 years ago

Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

@stgray We could add these types of limits into AtlasPlugin when the efforts are clamped if we had an appropriate model. We're open to suggestions / pull requests.

osrf-migration commented 10 years ago

Original comment by Brian Gerkey (Bitbucket: Brian Gerkey, GitHub: gerkey).

Awaiting updated torque limit data, from BDI or elsewhere.

osrf-migration commented 10 years ago

Original comment by Steven Gray (Bitbucket: stgray).

The torque limits are on the Box accounts provided to the teams with Atlases. Do you have access to that info?

osrf-migration commented 10 years ago

Original comment by John Hsu (Bitbucket: hsu, GitHub: hsu).

I believe the robot data provided by BDI do contain transmission and hydraulic data. Has anyone backed out the torque limits from there?

osrf-migration commented 10 years ago

Original comment by Brian Gerkey (Bitbucket: Brian Gerkey, GitHub: gerkey).

I does look like those docs contain torque limits for about half the actuators (in the ActuatorData.xls sheet, cells G18:H29); for the remainder it appears that the torque limits are configuration-dependent.

For the actuators that have fixed torque limits, we could use those values to replace the existing limits in the models. For the others, we would need to know how to compute the limits given the configuration.

But those docs are marked Boston Dynamics Proprietary Information, so we'd need BDI's permission before releasing any of the numbers.