Can we fix 6th axis?

Yu I

Hello,

Can we fix 1 axis? I want to fix 6th axis during simulation.

 

BR

Yu 

Henrik Berlin

Hi,

If you fix one axis you will loose one degree-of-freedom (DOF) for a floor-mounted, standard IRB. An object in cartesian space has six degrees of freedom (translation x, y, z, rotation Rx, Ry, Rz). Note that the rotation is parametrized by quaternions in the controller which is mathematically advantageous (q1, q2, q3, q4, and of unit length, i.e. normalized). Since a standard ABB industrial robot also has six DOF (the joints), it means that it has the potential to reach a general position (translation and rotation) in 3D space. The inverse kinematics problem (the calculation of the robot joint values to reach a given position in 3D-space) is well-posed since the number of unknowns (i.e. the joints) equal the number of known parameters (translation and rotation of given point). If you lock one axis of the robot, it will not be able to reach all positions.

 

My suggestion if you want to lock one axis is to use joint targets, where you can specify explicitly the value of each joint.