Robot return different joints position

[haenry11]

I create a scene with a pick and place robot arm. I use SimIK for Inverse Kinematic.
My robot plan is: From home position -> Move to grasp -> Then move back to the home position.
However, when the robot returns to home position after makes a grasp action, the position [deg] of joints are changed and the pose of robot is bad (even thought the tip position is same as the beginning).

How can I make the robot to move back exactly as its beginning pose (with the same joints position value)?

[fferri]

What is the size of the task and how many degrees of freedom has the robot?

If the robot is redundant for the task, there are infinite robot configurations satisfying the task, and you'll never get the exact same configuration for a given task.

[coppelia]

...unless of course you use FK instead of IK to drive the robot via its shortest path (in configuration space) to its initial configuration. You'd use for example sim.moveToConfig.

Cheers