Jack’s Status Report 11/9 – Team B1: Third Hand

Progress This Week:
- Designed wrist coupler to connect wrist motor to gripper
  - currently 3D printing
- Assembled exisiting parts. Ran into some issues so I spent significant effort on iterating the hardware.
  - The new linear slides I ordered arrived!
  - Assembled XY mechanism. However, some parts did not fit properly. Nonetheless, we were able to confirm that the gantry was smooth and had no perceptible sag or slack.
  - I used some hacks such as using fewer bolts than the designed number to make everything fit. However, I decided to redesign them so that they work properly.
    - Redesigned hardware are printing overnight.
  - The gantry+gripper hardware should be ready by Monday.
- Force control on gripper
  - For the MVP, we decided to not incoporate it because binary open/close modes should suffice for rigid objects. However, we still want to pursue force control for the final product.
  - Researched using Dynamixel smart servos to achieve torque control for the gripper. Sifted through documentation on all the models and reallized the cheapest model that offered torque control was $300.
  - Pivot towards homebrew mechanisms
    - Idea 1: same as originally proposed. Use torsion springs to act as a compliant mechanism
    - Idea 2: modify gripper mechanism to incoportate springs into the gripper.
    - Idea 3: use FOC (Field Oriented Control), an algorithm that achieves torque control in steppers by modeling the electromechanical fields inside the motor and energizing the windings to control the torque output.
- Goal next week:
  - complete software integration for the gantry/gripper. Currently, I have software that can control the gantry. However, I expect to put a significant amount into integration. Now that Leland is able to get XY coordinates from the CV stack, and Zhenghao has solved the FSR reading problem, all indiviudal software subsystems are in place.
  - Design and build new handheld controller housing.
    - We decided to pivot away from the PVC pipe chassis, as the electronics are occupying more room than we originally expected.
    - This is not crucial to the MVP, but we would like the MVP to look as mature as possible.
- Gantry assembly so far (x-axis belt not added due because I had to reprint a part in the x-axis mechanism)

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