DRCVehicle steering linkage model

osrf / drcsim

Repository for the DRC project.

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DRCVehicle steering linkage model #63

Open osrf-migration opened 11 years ago

osrf-migration commented 11 years ago

Original report (archived issue) by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

Currently the DRC Vehicle plugin controls the steering of the front wheels based on the measured hand-wheel angle. This does not allow force feedback from the wheels to be felt at the steering wheel.

If proper steering feel is necessary for the VRC, the model should be enhanced. Specifically, the model should have:

Rack and pinion steering linkage
Reasonable steering kinematics (kingpin and caster angles)
Reasonable tire friction model

osrf-migration commented 11 years ago

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

An alternative would be a feedback torque on the steering hand wheel, based on the steering error at the front wheels.

osrf-migration commented 11 years ago

Original comment by Alberto Romay (Bitbucket: romayiii).

In the current DRC Vehicle Plugin there is a PID controller in the hand-wheel. This works OK for the tele-operate tutorial of the DRC Vehicle, but it makes it really hard to use the robot's hands to turn the hand-wheel:

Hand-Wheel with PID

Changing the Force, Position and Velocity PID from the steering-joint on the simulator does not seem to help. Removing the PID controller of the hand-wheel from the DRCVehiclePlugin.cc makes it easy to turn the hand-wheel:

Hand-wheel without PID

However, this is a manual change in the source code and it would be helpful to be able to edit/remove this controller in the simulator.

The alternative of the "Steering-feel feedback torque" (i.e. while moving forward and try to turn) based on the error at the front wheels makes better sense than the PID that works even when the vehicle is not moving.

osrf-migration commented 11 years ago

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

The PID controller is used to tele-operate the steering wheel based on the ROS topic /drc_vehicle/hand_wheel/cmd, but I suppose we could turn it off for development. To be realistic, there should be some resistance, though; I'll work on figuring out some realistic levels of steering torque resistance.

We also may need to tune the contact parameters for the hands and steering wheel. @hsu

osrf-migration commented 11 years ago

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

changed version from "None" to "2.1.0"

osrf-migration commented 11 years ago

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

changed priority from "major" to "minor"
changed version from "2.1.0" to "None"

osrf-migration commented 11 years ago

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

changed state from "new" to "on hold"

osrf-migration commented 11 years ago

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

changed state from "on hold" to "open"