I started this project with AR2 in mind but I tried first with a mini version to avoid the size of a bigger one, but now I'm planning to build an AR4 with all the experience I earned with this project.

Here it is the final result of the project, Its "semi" closed loop 6 axis with a servo gripper. All the motors are Nema 17 with S42C Bigthreetech close loop drivers attached to an arduino Mega Ramps 1.6. I like to start my experience with this robot talking a little about myself. Im a university student in Ecuador so my original idea was build a open loop robot with steppers so my first option was the AR2 but it was so expensive to my initial idea, so I found this version based on AR2 and I 3D printed all the pieces modifying the original one, to attach nema 17 motors. The AR2 use arduino MEga but I think I would use a 3d printer shield so I buy de RAMPS 1.6 and modify the Arduino Source Code to work with the AR2 software and Matlab to, so here it is the final result.

First the electronics:

I use and old Fiery box with a 37pin cable for all the cables:

Enclosure:

A 12V power supply for all the electronics, and for the software I modify the arduino source code and I can control 6 axis + travel track and 4 servo motors on servo pins in the RAMPS shield to simply the wiring, I use only 1 servo motor for servo gripper based on AR4 gripper but I modify the CAD archives to use a micro Servo SG90 for the weight of the gripper

MCG are my name initials like AR :D, for the DH parameters I do a lot of work but I finally works with this parameters, thanks to @Chris Annin the DH parameters of the kinematics are in one excel sheet so I figured it out so my parameters are:

So I can finally work with all the stuff of the AR2 software:

For the size of the blog I cant upload a Matlab video but I let you here some screenshots but I explained here how it works, its a Inverse process control with the cinematic model of the robot so I use matlab for this and communicated with the robot using the same pins in arduino so here it is the results of using a HMI in matlab, so you Introduce a point in a XYZ plane and the end effector goes to that point without using the joint movements like this screens:

As we see in this picture the robot takes the XYZ space position, so if we gave another point, we make a final interpolation, like this

For more information of this Matlab control here it is a Youtube video

Thanks for @Chris Annin for this project all my results are for this project and youtube videos. If someone needs the Archives of all, please contact me commenting this post.

Now I planning to build an AR4 robot to control with vision.