Inverse Kinematics and hybrid operation mode

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BiancaSan93
Posts: 27
Joined: 25 Apr 2017, 17:26

Inverse Kinematics and hybrid operation mode

Post by BiancaSan93 »

Good evening,

I'm relatively new to V-REP and I'm trying to get a hold of the environment.
I need to experiment with inverse kinematics but I don't quite get the results I'm expecting.
I'm using the UR10 manipulator: I followed the tutorial about IK and created the IK group with IK elements and everything worked smoothly. The joints are all in Inverse Kinematics mode. However, when I start the simulation, the robot literally collapses on itself and falls to pieces.
The issue seems to be resolved when I check in the hybrid operation mode next to the Inverse kinematics mode in the joint dialogue box, alongside with position control (PID). I've read, however, that the hybrid operation shouldn't be active.
What am I missing/getting wrong? I believe it might be because the robot is dynamically enabled, but I'm not sure how to deal with that.
I'm sorry if the question is very naive, but I'd really appreciate if somebody could clue me in.
Thank you!

coppelia
Site Admin
Posts: 10339
Joined: 14 Dec 2012, 00:25

Re: Inverse Kinematics and hybrid operation mode

Post by coppelia »

Hello,

it really depends what you want to do exactly. If you do not need dynamics, then you should set all joints into IK mode (non-hybrid), and turn all shapes into static and non-respondable shapes. This way you will have a purely kinematics model of your robot.

Related the dynamics/physics simulation, make sure you have read this page.

Cheers

BiancaSan93
Posts: 27
Joined: 25 Apr 2017, 17:26

Re: Inverse Kinematics and hybrid operation mode

Post by BiancaSan93 »

Thank you for your kind reply.
I need to reproduce a scenario that is as similar as possible to a real life situation. In this case, should I operate in hybrid mode?

coppelia
Site Admin
Posts: 10339
Joined: 14 Dec 2012, 00:25

Re: Inverse Kinematics and hybrid operation mode

Post by coppelia »

When doing simulation, you will always abstract out one or another aspect, and work with approximations. So it is entirely up to you what aspect you need to be more realistic. But basically if in hybrid mode, the robot motors will simply use a PID position controller to try to keep the joint angles computed by the IK.

Cheers

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