Hexapod help

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AsadAli
Posts: 36
Joined: 24 Dec 2014, 09:25

Hexapod help

Post by AsadAli » 28 Dec 2014, 18:43

Hey everyone ,
-I have just started working on hexapod in vrep . It consist of a Lua script. I am not able to understand its mathematics how its calculating step size , making robot to walk . Is there any kind o tutorial or help that can help me understand this .
Thanks

coppelia
Site Admin
Posts: 7267
Joined: 14 Dec 2012, 00:25

Re: Hexapod help

Post by coppelia » 28 Dec 2014, 19:14

Hello,

the hexapod2 example might be quite complicated, since the purpose was to demonstrate distributed control. So there is a child script for each leg, in charge of applying a foot movement computed in the child script attached to the model base. Each of the leg child script applies the foot movement in a delayed fashion (as far as I remember: leg1, leg4, leg2, leg6, leg3, leg5, in that order).

The hexapod1 example is a little bit more simple: the threaded child script attached to the model base is in charge of defining what type of movement is wanted. Then, the non-threaded child script attached to object hexa-body is in charge of handling the inverse kinematics for each of the 6 legs, depending on the movement mode set by the other child script.

Cheers

AsadAli
Posts: 36
Joined: 24 Dec 2014, 09:25

Re: Hexapod help

Post by AsadAli » 28 Dec 2014, 19:50

Hey thanks for quick response , hey i was able to understand the base what these files are doing but i am not able to understand how doing how these scripts are using maths calculation like calculation of dx , dt and etc so is there any help for understanding this , any written , video tutorial . Any help will be really appriciated.

coppelia
Site Admin
Posts: 7267
Joined: 14 Dec 2012, 00:25

Re: Hexapod help

Post by coppelia » 29 Dec 2014, 00:00

There is unfortunately no tutorial for the hexapod robot that explains the algorithm. However there is this tutorial.

Cheers

AsadAli
Posts: 36
Joined: 24 Dec 2014, 09:25

Re: Hexapod help

Post by AsadAli » 29 Dec 2014, 07:59

Then this means that we cant use this build in walk beacuse if we cant uderstand the alogrithm then how can i be able to reuse that . Thats not fair atleast there must be somekind of help regarding algorithm as well.

Eric
Posts: 186
Joined: 11 Feb 2013, 16:39

Re: Hexapod help

Post by Eric » 29 Dec 2014, 14:49

The aim of the sample scenes is do show what V-REP can do and provide some help on how to implement stuff... It does not aim at providing the basic robotic knowledge. To get the knowledge on robotics ( and algorithm) there are plenty of online classes, including some using V-REP as a tool to implement algorithms (as for example this very good one.

Please also bare in mind that V-REP is a free tool for students or hobbyists like you, and that the forum comes as a free way to help people with the use of V-REP, not as a hand in hand guide way to go through robotics and algo implementations (unless you are a paying customer with a paying support I believe).

My suggestion is that you remove the content of each script inside the hexapod model and code your own walking motion controller, in an other way than the one you can not understand, using for example the content of the 1st chapter of the MOOC linked above. You can use the already functional hexapod model as an empty shell for your controller. The tutorial provided give you the basic knowledge on how to sense and actuate.

Along the way if you find some implementation issues related to the use of the API for example, then you can ask specific questions in this forum and get the appropriate help.

Also coppelia robotics offers paying services to develop specific model, scenes and plugins as well as some formation for the use of V-REP. (contact)

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