I found out about Circuit Specialists (CS) when I do some research for my Rover Repair Robot. The company offers the best servo motor for the price, and, I did an instucables on how to modify these servo motors. You can click here to find more information about the modification and about the company.
After speaking to the product manager and sharing my instructable's page I got a call from the company couple days later. Very please with the projects page, they offered me a temporary partnership to run a workshop at Arizona State University. The company had scheduled a robotic workshop at ASU on April 6, and they would love to have their version of 3D printed robotic arm using the company servo motors however the workshop is about a month away. I made a list of things need to be done, design the arm and the control unit, coding the arm and facilitate the workshop.
The workshop with IEEE ASU Chapter was a great success, to some team members that was their first time hand on a robotic arm. I was very excited to explain to the students about my project and the history of the industrial robotic arm. Some of the students came up to me later to have some very interesting questions about robotic arm and system control theory.
The company and I decide this project would be open sources. Which mean we will upload all STL files and the code for this 3D printed robotic arm. That is a reason why I write this instruction to be a basic guild for assembly and coding. Now lets start making, Makers!!! :P
Step 1: Plan of Attack!!!
The workshop's time was one of the greatest challenge for me, since I only have 1 hour and 30 minutes for a presentation, electronic assembly, upload the code, hardware assembly, testing the control unit. I also had to make sure my presentation not too long because I want each team has most of their time to be "hand on project".
The picture at the introduction speaks for the size of the audience that day, it was 5 CSRA kits with servo installed ready for the workshop. I design each of the parts so that they could hardware assembly before the workshop, save us some time. My main goal for the workshop was showing the students the important of following the instruction, upload the home position for the CSRA to the final step of the assembly, connect all components together.
I acknowledge this is one of the most common problems in the robotic field. Any type of robot you can name it, quadruped, humanoid, etc. only can work efficiently if they were homing the their home position properly, and robot arm is no different. Failing to "homing" your robotic project properly could cause a ripple effect to later performing of the project and could cause the significant decrease in the life span of the robot.
To any makers that want to 3D printing these parts and build one for your own work table, I will post step by step how to assembly all these components. Most of these parts are friction fitted, however, I still have indicate hold for you to screw in 2 of the servo screws.
Step 2: Base Assembly.
Most of the picture speak for themselves, however if you have any question just leave them in the comment area, I promise that I will answer them as soon as possible. : D
My first advice, you should already have the CSRA code ready and also check out the PowerPoint that I put together for the workshop. It will explain the electronic components in this project better.
My second advice, you should pre-connect all the servo to the microcontroller. Open the CSRA source code in the Arduino Enviroment, in the void loop, you could uncomment this line of the code to "home" all your servos.
//Arm_IK (15 ,5 ,1) ;
By "homing" your servos now, the job would be much easier later when get to the final assembly step.
Step 3: Main Arms Assembly.
Step 4: Gripper Assembly.
Step 5: Final Assembly. "Homing"
If you did take my advice and " home" your servo at the beginning now would be your pain. We need to connect all servo to the microcontroller, upload the CSA code with the homePos() uncomment.
The first thing you may notice id the rotation base was not centered, which mean you have to undo the base and redo the first assembly test with the servo plug into the microcontroller. This way your robot arm will face the right direction.
After upload the homePos code to the Arduino and have all the servos plug in, connecting all the part orientate the same way like the picture and screw in the servo's screw to secure everything in place.
Congratulation, you are done with the basic assembly and coding. There will be part 2 where I explain more about the control unit, battery source, and Inverse Kinematic. However, the source code I have provide you have the Inverse Kinematic Algorithm and PotControl Algorithm, please feel free to play around with it.
If you have any question, please leave on the comment box below and I will answer as soon as I can. Thank you.
Step 6: Circuits Specialists Robotic Arm Competion .
The students joined the workshop had a blast at the CSRA competition at the end. Some of the team did not follow the instruction causing the robot arm to be malfunctioning. Some of the team take too long to assembly the robot causing them time to practice with their robot. And that is all part of the game, if you follow the instruction, " homing" properly, practice with your robot, you will win.
There are lots of improvement on the CSRA design and the workshop structures that I could do for the future workshop. For now it was a great opportunity and experience, and it is only possible because of Circuits Specialists and IEEE ASU Chapter and of course you, Makers. I am greatly appreciated.
Any questions please leave it in the comment box below, and I will answer you as soon as I see it. :D
Circuits Specialists website : https://www.circuitspecialists.com/