Aspects of hexapod

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pjburton
Posts: 5
Joined: 14 Mar 2020, 01:25

Aspects of hexapod

Post by pjburton » 25 Mar 2020, 04:12

I am trying to build a model similar to the hexapod tutorial. I would like to know how to set up the inverse kinematics so that the feet remain fixed and the body moves with the legs adapting. I would also like to know how the hexa_legBase dummy is connected to the hexabody object, as this does not seem clear from the scene hierarchy.

pjburton
Posts: 5
Joined: 14 Mar 2020, 01:25

Re: Aspects of hexapod

Post by pjburton » 25 Mar 2020, 21:36

When I try to replicate the hexapod, what happens is the feet move and the base remains stationary. I would like the base to move and the feet to remain stationary.

fferri
Posts: 556
Joined: 09 Sep 2013, 19:28

Re: Aspects of hexapod

Post by fferri » 25 Mar 2020, 21:56

Is the base static?

coppelia
Site Admin
Posts: 7706
Joined: 14 Dec 2012, 00:25

Re: Aspects of hexapod

Post by coppelia » 26 Mar 2020, 10:32

Hello,

when building such a model, make sure you start first with a static robot, and have the IK worked out first.
There are probably several ways to do this, but I'd model the hexapod in following way:

Code: Select all

body --> baseDummy --> foot1TargetDummy
                   --> foot2TargetDummy
                   --> foot3TargetDummy
                   --> foot4TargetDummy
                   --> foot5TargetDummy
                   --> foot6TargetDummy
     --> leg1Joint1 --> leg1Link1 --> ... --> leg1Link3 --> foot1TipDummy
     --> leg2Joint1 --> leg2Link1 --> ... --> leg2Link3 --> foot2TipDummy
     --> leg3Joint1 --> leg3Link1 --> ... --> leg3Link3 --> foot3TipDummy
     --> leg4Joint1 --> leg4Link1 --> ... --> leg4Link3 --> foot4TipDummy
     --> leg5Joint1 --> leg5Link1 --> ... --> leg5Link3 --> foot5TipDummy
     --> leg6Joint1 --> leg6Link1 --> ... --> leg6Link3 --> foot6TipDummy
You have 6 legs. Each will result in an IK group for IK. If you want to move a single leg (e.g. up), then shift one of the footTargetDummies. If you want to move the body while keeping all feet in the same position relative to each others, then shift/rotate baseDummy.

Cheers

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