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Robotic Arm!

TehMaxwell

Tales of a Rookie
#1
Hey all,

I haven't been on the forums for a very long time, life has been kind of busy due to exams and other things getting in the way of RC. But now it's time to pick up the transmitter again.

I say that, but I must apologize, as this post is not strictly RC related (although it could be in the future). But in my opinion it's just a tad to cool not to share, so I thought Id put it in the scratch builders section, as it isn't store bought. Introducing, my Robotic Arm, which doesn't really have a proper name yet!

The arm is my school project for this year. It has six points of rotation (Base, Shoulder, Elbow, Wrist, Wrist Rotate, Claw), all of these can be controlled by one micro controller board. It's a built up construction of Laser Cut Ply Parts that are held together with a combination of screws and wood glue, the separate sections are rotated by seven different servo's (the shoulder has two combined for added torque) which provide around 2.5kg per cm of torque (I think Im saying that right) at 5v and around 3kg at 6v. During testing the arm nearly threw itself off of the table, it can definitely handle it's own weight and needs added weight in the base. I am using brass tubing for the pivot points so that the separate sections can rotate smoothly around each other. Here is a picture:

Robotic Arm.jpg

When this arm goes off for marking it will be controlled by a PICAXE Microcontroller. I have only really recently got into programming properly, my only past experience being a graphical interface called Logicator which is used to program the PICAXE Chips. I have been trying to learn Python by making different little programs, such as a number sorting program and a riddles game. I have also bought an Arduino Starter Kit as I enjoy controlling things in the real world, and until I bought the kit I had no electronics at home. Not even a bread board. This will allow me to tinker to my hearts content!

So my question is, has anyone in this community got any experience with Arduino Control and if so what sort of set-up would you recommend for controlling the arm. I was thinking a series of potentionmeters, two touch pads or a Joystick. Something cool and intuitive to make it easier to control.

Thanks all,

TehMaxwell
 
#3
Using an arduino and a bunch of pots, you can probably write all your code in less than 20 lines. So, yes, that is by far the easiest way to go. If you have any Java experience, making a GUI in processing and connecting that via Serial to the arm will be a piece of cake, and probably much more user friendly. Then you can simply use keyboard input and on-screen buttons/sliders to control the arm.

IMO, the ultimate controller would be a smaller version of the arm with pots at the joints, where the larger version mimics the smaller version. So the user simply manipulates the mini arm, and the big one copies their motion.
 
#4
Raptortech makes some good valid comments and I like the idea of a smaller version with pots on the joints.

But the real use of robot arms in industry is for repetitive tasks like assembly, welding or painting.

I would concentrate on the programming side and make it do something like pick up a pen and draw a shape. Or put a lid on a jar - something that would need some sensors to locate the parts and put them together.
 

DamoRC

Well-known member
Mentor
#5
You could use your RC transmitter! Feed the signals from a receiver to the UNO, process them, and resend to the servos for the arm motions. 4 independent axis controls at your fingertips and the arduino could be programmed to interpret certain stick combinations and switch positions for additional movements or set pieces.

DamoRC
 

TehMaxwell

Tales of a Rookie
#6
All interesting ideas! I have seen the idea of making a mini version and mapping its movements online before, it looks great and may be future project that I can do. I may start by getting the arm to do things automatically using sensors as Kevin said, then use my RC transmitter to control it from range and then use a smaller version of the arm to control it.

Watch the articles space as when the build is fully complete I am going to post an article on the build as well as a timelase that shows the whole build process!

Thanks for all the input, and if you have an questions about how it was built then don't hesitate to ask, anyone who is into servo control would love building one of these.