Robotic Gripper
For this project, I worked with a team of two other engineers over Zoom. We were tasked with designing, creating, and presenting a device to assist a differently abled person in their everyday life. After discussing and brainstorming my team decided that our goal was to create some sort of robotic device which helped a person pick up objects. After prototyping, we settled on the design seen above with the bulk of the electronics attached to the users arm, a two prong gripper style end effector, and all controlled by a joystick mounted near the thumb.
During this project, my team and I learned the challenges of remotely collaborating on an engineering project. We managed to convey to each other our ideas by sharing drawings and demonstrations with our own prototypes over video call, as well as sharing and testing each others code snippets. This project also exposed me to the challenge of learning on the go, as I had no prior knowledge of Arduino code nor how to integrate the numerous other modules we used in conjunction with the Arduino. When we introduced the stepper motor when working on the final design, I found that my stepper motor would not respond properly to the basic stepper motor library default to Arduino. So instead of having to learn the commands of the basic library, I had to learn the much more advanced AccelStepper library which complicated the code immensely, and was much less documented. With the support of my team, I learned and grew as we progressed through the project, and by the end felt very confident in my abilities.
Prototype 1
This is the first prototype I made for this project, made out of cardboard, tape, a ruler, hot glue, rubber bands, toothpicks, and string as a proof of concept of our design. The mechanism to operate the gripper can be seen on the underside (right picture), where a finger would pull the point where the string is connected together by take to actuate the gripper.
Prototype 2
This is the second prototype, a modified version of the first where I added the electronic components of an Arduino Uno, a servo motor, and two 5V batteries, all controlled by the button on the breadboard next to my thumb.
Final Design
After noticing that the servo motor couldn't deliver enough power to lift up heavy objects, we upgraded to a stronger stepper motor, as well as giving the user more fine control with a joystick module rather than a simple button. All of this was added to the final frame made from 1/16 in laser-cut plywood to keep everything sturdy.
Demonstration
This video shows a demonstration of the final product, capable of smooth grip and release of objects much heavier than the initial prototypes.
What could be improved?
While the stepper motor has much more power than the servo motor, it opens and closes the grippers much slower than the servo motor did in the earlier prototypes. Also, the stepper motor is unable to be programed to open and close to specific positions like a servo motor can. So, I believe a future version of this project should use a more powerful servo motor as it would enable the gripper to open snappier and stronger, while still giving the user fine joystick control, as well as enabling an open and close toggle button. It could also be beneficial to swap from a two prong gripper to a three prong gripper, as it would enable a wider range of objects to be picked up.