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solution.
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Joint space
In joint space, the robotic arm has 5 degrees of freedom to control
and can switch to joint commands when different orientations are
required at the end. Then use the joint command again to return
the flange and the base to a horizontal attitude, and you can switch
back to Cartesian control. A quick way to set a cartesian
controllable attitude is: Just set the angle of J4 equal to-(J2 angle +
J3 angle).
2.4. Singularity
1.Concept
Singularities occur when the axes of any two joints of a robotic arm
are on the same straight line. At the singularity point, the robot's
degrees of freedom will be degraded, which will cause the angular
velocity of some joints to be too fast, leading to loss of control. A
common situation is that when the wrist joint (the penultimate one)
is at or near the axis of the first joint, singularity point will also
appear (see Figure 2.1), so the robotic arm should try to avoid
passing directly the central area near the base, which is likely to
