Warman 2015University of Technology Sydney

A. Gillmore B. Potts T. Dalyell S. Abid D. Brown

Brief outline of activities and decisions

• Brainstorming- Device collecting 6 balls with path straight down the track- Suction cups

• Concept- Keeping the design simple - Collect and store 3 balls before continuing to the next three- Aiming for biggest storage pit due to minimal point difference

• Design - Dagu Rover 5 tracked chasis- 2 DC motors with 4 encoders- 2 Servos operating collection arm

• Production- Laser cut sheet acrylic (3/4.5mm)- Different sized spacers to control ball arm height

• Testing- Ahead of fabrication schedule allowed us maximum track testing time- Laser cut starting jig with adjustable spacers

• Execution- Followed from testing

Project and device requirements

• Collect 1-6 balls put in 1 of 3 storage pits; • Off the shelf kits not allowed; • Start button can not impart motion; • 120 second set up time, 120 second run time; • No contact with robot after start; • Wireless communication prohibited; • 6kg, 400mm cube restriction; • Robot must stop moving after completing the course.

Detailed explanation of the device

• Prototype 1 - Tolerance issues- Group discussion following testing we decided to continue brainstorming another idea as we had plenty of time remaining

Concept Design

Detailed explanation of the selected device

• Final Prototype - Dagu Rover 5 Tracked Chassis

Concept Design

Detailed explanation of the selected device

• Final Prototype - Mechanical linkages to operate the gates - Arm is connected through cantilever under the Dagu

Concept Design

Detailed explanation of the selected device

• Design Mechanics - Two Servo motors;1 for Ball gates and a second to keep the collector arm within the 400mm requirement

• Meeting the design requirements - Start button correctly installed - Dagu max speed was 25cm/s allowing plenty of leeway to fit within time limit- Total system weighed under 3kg - Total system was within 400mm Cube due to folding arm design

Two key issues overcome by the team

• Driving Straight

• Encoder resolution

• Physical design of Robot

• PID controller code modification

• Starting position

• 1 degree of inaccuracy at start resulted in 35mm East west variation at 2m

• Laser cut starting jig with adjustable spacers

Videos

5 Balls collected and stored in the large pit

Event day

Final Device Analysis• Rules/requirements met

• No combustion/Aerial systems

• 1 button push start

• Met all size and weight (final weight -> 2.8kg) restrictions

• Device Weaknesses

• Tracked chassis, encoder resolution, starting position could be refined

• Improvements

• IR sensors to detect edge and drive robot straight

• Replace tracked chasis with rear wheels and front castor

• Positives

• Build quality

• Collection mechanism if positioned properly never failed

• Speed

• Team time management (8am lab sessions, early prototyping)