Custom v-rep robot

Hello everybody,

I’m starting to work with python and a Pypot in the VREP,I want to build a customize machine that made by myself not PoppyTorso or PoppyHumanoid because it’s so hard to learn.
I want to build a Four-bar linkage can simulation in Vrep and real .

How shoud I work with this or have any example to learn?

Here an example of a simple creature :

Ok, you want to build a robot real and simulated with pypot for controling Dynamixel motors and you also want to have the simulated robot.

Is it for personal use or have you an other purpose ? I can guide you through all the process but you have to be aware that it is quite a big work !

First, do you want to focus on the real or the simulated robot ?

Do you have your machine in a 3D Cad, like Solidworks or onshape ?

Thank you to reply my answer. But I didn’t design all the machine a way.

I’m design a 3d printer like the delta machine (The file )

and the controller is arduino with ramps1.4.

By the way. Can pypot control the stepper motor or Mg995 servo with Arduino in real time ?

Or can control with the Vrep ?

Do you want to simulate you 3D printer with vrep and pypot ?

Pypot can control all the motors, but actually only the IO for dynamixel are fully functional. If you want to control other motors you need to write you own controller. See the dynamixel folder of pypot to understand how it works.

In vrep, no problem to control joint for every models. What you need is just to write a configuration file to describe your robot. Follow the ergo model ergo.json and write your own robot.json
Replace the ergo model with your .json and your .ttt and it should work in vrep. You need to have the same name for motors in vrep and in json.

Hm’m I try to control four bar like with dummy like this

But can’t control the bar with dummy.

I delete the dummy that I can control the link but can’t do the correct motion in the vrep.

Does the pypot only can control the open loop or just I didn;t do correct setting ?

Your problem seems to be a pure Vrep problem. Before doing anything with pypot, your vrep model have to move correctly when you change the angles of joints in the join property dialog box.
I don’t understand what is dummy() ? Why did you delete a joint (revolute_joint2) in your second vrep model ?
Can you give your vrep model so I can have a look on it ?

Explanation of dummy link here :

Your dummy link should not be in your json configuration file because if I understand correctly these are a sort of passive joint just following the bar’s position.
And when I’m thinking of this… maybe it will raise issues with this kind of joint. Post your vrep scene somewhere so I will be able to make some tests.

OK I’have upload the ttt in here

Thank you to help with me. I’m trying the close system can be control with pypot ?

Or just my json config didn’t setting correct (file)?

Here have a question about pypot thread.

The from_vrep API and API

I wnat to use the from_vrep function to start vrep simuration and get the motor force and position. but that have an error like below . what shoud i need to get.

should i give up the from_vrep and use vrep_io to start the smuration ?

Could not connect to V-REP server on This could also means that you still have a previously opened connection running! (try pypot.vrep.close_all_connections())

First, your vrep model is not good. You should have master and passive joint to control a close loop like you have in your contruction. I think here is the explanation on how to do this :

You have to make the diffence between the joints you want to set the position and the joints you want to adapt their position function of the others (using dummy or dependant mode should work but I never tried)

You can also ask your question on the vrep forum, normally you will have an answer quickly :

Second, to control a vrep model you need the timer() script, the one you can find in every model working with pypot (roboticia or poppy).

Second question, use vrep io like this : Add new sensor in VREP scene and working with Pypot library