(Currently up to date for Preliminary Competition)

Table of Contents

• Project Description
• Hardware
• Electrical Systems
• Getting Started

 

Project Description

Competition Environment

 

Task Description:

Build a mobile robot to collect and store as many ball bearings of a known diameter and appearance as possible. Target bearings will be spread across an arena, with distractor bearings intermixed.

 

Components Used:

• 1 x Dual motor Tamiya gearbox and 2 DC motor with encoders
• 1 x Castor wheel
• 1 x Jetson Nano (4GB)
• 1 x Arduino Nano
• 1 x Motor Controller (TB6612FN)
• 4 x Ultrasonic (HCSR04)
• 1 x Power Bank (ROMOSS 10000mAh 18W)
• 1 x 9V Battery pack

 

Hardware

The hardware side involves the design, manufacturing and testing of a main chassis which will incorporate all the components, a target storage system, internal distractor filtering ramp, and a target collector mechanism.

 

Main Chassis

Chassis Rev_1 (Stage 4)

 

*CAD files for main chassis to be added for Prelim

 

Collector Mechanism

CAD of the target collector & filtering mechanism

 

This system consists of a plow, ramp and paddle spindle. The plow (similar to a snow plow) is slightly higher than the diameter of the target balls (¾”) and as such, limits balls larger than this from entering the collector. The wedge design ensures these balls are pushed to the side as the robot moves forward, such that more balls can enter the front of the collector.

The paddle spindle consists of 3 paddles on a central axis. This shaft rotates such that the paddles scoop up balls as the robot drives forward and lifts them up the collector ramp, into the main body of the robot to be sorted.

Sorting of target and non-target balls will be performed through the use of two rails, with separation slightly less than the target ball diameter. These rails will be sufficiently far apart, to allow balls smaller than the target to fall between the rails and hence be expelled from the robot. Larger balls will be unable to enter the ramp as the collection system plow forbids it. At the end of the rails will be a collection bucket, into which the target balls will fall.

 

Electrical Systems

Electrical connections

 

The electrical systems is powered by a portable powerbank (5V/2A) for the Jetson and six AA battery pack (9V/~A). This is expected to power the robot continuously for 30 ~ 60 minutes for a continuous load.

 

 

Electrical Loom for Preliminary Competition

 

Getting Started

Installation

Setup Jetson to run ROS and Arduino IDE

• Tested with ROS Melodic with Jetpack 4.5

TODO:

  - install.sh
  - requirements.py
  - setting up GPIO pins 
  - test scripts

How to run

(For Preliminary Competition)

  $ roslaunch comms comms.launch

• wait until encoder nodes are running

  $ rosrun comms republisher

  $ roslaunch diff_drive demo.launch

Publish position coordinates to

"/diff_drive_to_goal/goal"

• Input position must be based on the robotics coordinate system

Features

• Move to desired position in a 2D space
• Dynamic obstacle avoidance and replanning (tailored for the preliminary competition setup)

 

Authors:

• Kevin Lee
• Kurtis Brandt
• Jin Siang Ong
• Surya Kannan