Why the robot performs the same when I adjust the Roll and Yaw?

It normally happens when the Pitch=±90°, it's the gimbal lock, there are 2 typical features of the gimbal lock on the robotic arm.

1. When the robot is at a pos of Pitch=±90°, adjusting the Roll of the robot will get the same result with adjusting the Yaw. You can bypass this issue by switching to the "Tool Coordinate" on UFACTORY xArm Studio or use the "set_tool_position" of the UFACTORY xArm Python or C++ SDK.

2. When the robot at a pos of Pitch=±90°, the robot will report a different Roll and Yaw with the pos you sent to the robot, but (Roll_send-Roll_report)+(Yaw_send-Yaw_report)=0 or ± 360°

Here is an example to show the feature (1).

Here is a video to show the result

Here is an example to show the feature 2

Note: If you are using xArm5, no worry about this problem.

If you'd like to know more about gimbal lock, see the page of WIKIPEDIA