For our final design, we decided on a mechanism that uses a system of connecting links to mechanically couple the vertical motion of the four-bar rocker to the clamping motion of the claw. As the rocker moves through its range of motion, a secondary linkage transmits this motion to a sliding T-bar within the claw assembly. This converts the rotational motion of the rocker into linear motion of the slider, which in turn actuates the opening and closing of the claw jaws.
Connecting Rods to Combine Motions
Solidworks Assembly
Assembly
Final Design
Our final product consisted of the 4-bar crank system, the claw mechanism, the base, and the integrated circuits that powered the motor to actuate our robot arm.
In terms of circuits, we used an Arduino, a breadboard, a 9V battery, and a 13-kg servo motor.
Arduino Code
The code we used reads the joystick’s input and checks how it’s being moved. When the joystick is adjusted, the servo motor responds by changing its position, which controls our arm to open and close. This allows the 4-bar crank mechanism to pick up and release objects smoothly.
Updated BOM:
Part | Purpose | Quantity | Price | Source |
|---|---|---|---|---|
2 ft x 2 ft Acrylic Sheet 6mm | Used for double rocker links and claw arms | 1 | $32.00 | TIW |
Rotary Bearings | Reduce friction at joints | 10 | Excluded from BOM | TIW |
6mm x 200 mm Bearing Shafts | Connect links | 5 | $3.20 | https://www.amazon.com/dp/B0D5D5L5CQ?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 |
Servo Motor | Actuate double rocker | 1 | Excluded from BOM | TIW |
Shaft Collars | Secure shafts | 14 | Excluded from BOM | TIW |