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I believe Autoware used to provide a branch for PACMod to control vehicle without node SSC. But as it seems the branch is deleted now. Does anyone have access to the previous branch of the autoware?

asked 2020-07-15 15:26:27 -0600

sudip gravatar image

I believe Autoware used to provide a branch for PACMod to control vehicle without node SSC. But as it seems the branch is deleted now. Does anyone have access to the previous branch of the autoware?

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answered 2020-07-18 18:42:07 -0600

Josh Whitley gravatar image

As far as I know, this has not been the case, as long as I have worked in the project (since version 1.9.0). PACMod vehicles have always required SSC or other custom interface software because Autoware.AI produces high-level commands (like desired speed and heading angle) and PACMod accepts low-level commands (like pedal and steering wheel control). However, you should be able to implement a simplified version of SSC on your own pretty easily with some basic PID control.

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Hi Josh, I am trying to implement a simplified version of SSC on my own. I am a newbie in this field. I am confused about where do I start. Your suggestion are highly appreciate.

sudip gravatar image sudip  ( 2020-07-20 18:19:30 -0600 )edit
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I would start with a simple PID controller to convert the desired speed to pedal controls. I believe the output for lateral control is in the form of a geometry_msgs/TwistStamped which is in an autoware_msgs/VehicleCmd. The Twist will contain a quaternion which you can convert to roll/pitch/yaw, of which the yaw is the desired vehicle angle. You will then need to convert this into a tire angle using a vehicle model of some sort (a simple Ackermann-style steering model should be fine) and then use the wheel-angle-to-steering-wheel-angle ratio to get a desired steering wheel angle. You can get this value from the vehicle manufacturer or from AutonomouStuff. That value can be used to command steering. I hope this helps.

Josh Whitley gravatar image Josh Whitley  ( 2020-07-20 18:31:46 -0600 )edit

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Asked: 2020-07-15 15:26:27 -0600

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Last updated: Jul 18 '20