Rover Not Staying at Constant Speed in Guided Mode


My team is using a Nvidia Jetson TX1 and a Pixhawk with Arudrover. We are attempting to navigate a rover in a Guided mode using the Intel Real Sense Stereo Camera. We are having some trouble sending commands to our Rover in Guided mode.

Here is the command we are sending:

rostopic pub -r 10 /mavros/setpoint_velocity/cmd_vel_unstamped geometry_msgs/Twist ‘{linear: {x: 0.1, y: 0.0, z: 0.0}, angular: {x: 0.0,y: 0.0,z: 0.0}}’

The rover starts out going a normal speed and then slows down to zero. It does the same thing the next loop but increases its speed each iteration until it goes uncontrollably fast. We tried tunning the PID by increasing P at first and increasing I but there is little change.

The video link here demonstrates the issue we are running into:

The two issues we are facing:

  1. Why does the rover stop each loop? Why is it not moving forward at a constant speed as it should be?
  2. Why is the speed not staying constant and blowing up exponentially each loop?

Any help would be much appreciated. We have a demo for our project on Tuesday.