Mechanical

Overall Design

The robot is designed to have two layers. The bottom layer houses the drivetrain, the opto-reflective sensors to detect the acorn, and the popular opto-reflective sensors for tape following. In between the two layers is the shooting mechanism made of 3D-printed gears. The top layer consists of the servo for the shooting mechanism as well as the mount for the yard detection servo and the IR servo. The top layer is also used to mount the PICs, Power distribution board and the H bridges.

Assembly Notes & Material Selection

The robot is made out of laser-cut Duron panels. It was designed to be easy to assemble. 3D-printed PLA was used to make the motor mounts for the drive train and the pillow blocks. Fasteners were used to mount the PCBS to the laser-cut Duron. Materials were primarily chosen to create a cost-effective and easy-to-assemble and disassemble bot. Duron sheet and PLA offer cheap and rapid prototyping capabilities.

Drivetrain

The drivetrain system is an important part of the robot. it consists of pillow blocks with ball bearings and shaft couplers for added supports. Some of the key components of the SQRL are:

Differential drive system
DC motor with drive break mode used

Magnetic Encoders for a Control Law Implementation

Shooting Mechanism

The team iterated over two designs for the shooting mechanism. The shoot mechanics implemented first was the spring-loaded one which worked fine with the beachtop supply but when integrated with the Power distribution board caused a lot of issues. Using a servo to the PDB seemed to cause fewer issues in general hence the team pivoted to a new shooting mechanism. The shooting mechanism with the gears and servo was easy to test with and easy to integrate with the overall design.

Shooting Mechanism 1

This shooting mechanism utilizes gear ratio to speed up the servo

Two pairs of gears in total: 5:2 and 5:3, resulting in a gear ratio of 1:6
The servo has a around 55RPM under 5V and a stall torque of 10kg*cm
Sweeping arm is 16 cm with ~15g weight attached, giving it enough momentum to knock back the Acorn

Assembly Drawing

IMG_6092.MOV

Shooting Mechanism 2

This shooting mechanism utilizes spring cam system

The cam rotated by a DC motor to compress the spring
The cam has one side of gradual curve path for compression and one side with steep curve for releasing
This design is unused due to the unknown circuit issue with integrating one more DC motor into our PDB

Assembly Drawing

Page updated

Report abuse