RedundantRob moving slightly on simulation start

[SmolElephant]

Why does the redundantRob 7 DoF manipulator model move on simulation start?
It looks like each of the joints vibrate, and the tip moves by (0.006, 0, 0.008)
Is it possible for the robot to be completely still on simulation start?
I am concerned about how accurate inverse kinematics can be.

Cheers

[coppelia]

You are talking about a simulation where you have IK being computed, and applied as target joint angles for the dynamically enabled joints. The joints are controlled via a PID controller in order to reach the target angle at each time. That's where your slight movement comes from. You have several possibilities to reduce/avoid this:

• use a better physics engine. e.g. Vortex
• Adjust the force/torque of the motors
• adjust the masses/inertias of the links
• adjust the PID controllers
• write your own joint controller

Cheers