BB8 won't move sideways 5.4 services quiz

Course Support ROS Basics In 5 Days (Python)
1

When I ask for a twist with linear component in the x direction BB8 moves.
However, when I change the direction of motion to be in the y direction BB8 does not move.

image

Am I correct to believe that BB8 should be capable of omnidirectional movement? If I recall correctly, the BB8 keyboard teleop demo in the introduction to Linux course allowed BB8 to move sideways.

For now, I can change BB8’s heading to complete the quiz but, I’d like to know if I’m missing something.

2

Hi Steve,

You need to set angular.z rather than linear.y to turn the robot. And try values lower than 1 (0.1 - 0.5) for all directions first so the BB8 doesn’t turn or move too fast.

3

Thanks. Because the lower half of BB8 is sphere, I thought it would be possible for the real life robot to move in all directions. After doing some research, I found a picture of the internals of the BB8 robot and now see why I have to steer it like a differential drive robot.

https://www.researchgate.net/figure/The-Sphero-BB-8-robot-a-The-robot-in-motion-showing-the-spherical-shell-1-and-the_fig1_329730240