Panther - Reinstall system

Hello,

I am writing this email to request a technical support.

We have bought two Panthers produced by your company. We notice that the Panther are equipped with Raspberry Pi 4B as internal computer. As a research project, we would like to do some modifications on the motor controller (such as PI or MPC controller). However, we do not know how to get access to the source code in the RPI. There are some instructions about system reinstallation in the manual. But we can not find the way to get access to the SD card. Therefore, it would be great to have some help from your side.

I am looking forward to your reply as soon as possible. Thank you.

P.S. The serial number of the Panther(version 1.2) is 22c6.

Hi xuhu7477,

We don’t share the source code for building the RPi operating system image. You can check the source code of every ROS pkg created for Panther and included in this image on our GitHub. Panther was developed with an intention of not making any significant changes on internal computing unit by the user. That’s why we are offering additional user computers dedicated for software development.

Could you share why do you want to change something in the RPi?

Best regards,
Hubert

We notice that panther accepts /cmd_vel as control signals to RPi. But the source code from Github indicates that the speed control for the wheels are open loop (maybe i am wrong at this point :sweat_smile:). If we want to implement some feedback controller, a direct access to control the BLDC motors would be necessary for us.

Hi xuhu7477,

Yes, Panther accepts /cmd_vel as a control signal, but it uses closed-loop speed motor control. PID controller is implemented on motor controller firmware layer. You don’t have to implement any feedback because you already have access to encoder tics and joint state on ROS layer in proper topics.

I hope this clarification will help to go on with your development :slight_smile:

Best regards,
Hubert

Hi Hubert,

This clarifies my confusions. But in case we want to restore the factory settings in RPi, as written in the Panther manual, how to extract the SD card from RPi and reinstall the system?

Regards
Xujiang

Hi xuhu7477,

You have to get access to the service space of the Panther. To access the components in service space, pivot the top rails by removing 2x shoulder screw and 2x nyloc nut. Then unscrew Deck (17x DIN912 M5x12). You can check it here.

Best regards,
Hubert