Lunabotics Positioning System Proposal UAH Lunabotics Team January 11, 2013 Mark Becnel Ethan Hopping

What is Lunabotics? Competition Goal: Create a remotely operated excavator capable of mining and depositing a minimum of 10kg of lunar simulant in 10 minutes Excavator must navigate from a starting position across an obstacle region to a mining region Excavator must extract regolith, return across obstacle area, and deposit regolith in a bin Points are awarded or deducted for a variety of factors including mass of regolith collected Links to full rules can be found at: http://space.uah.edu/lunabotics Introduce purpose of Lunabotics. Discuss basic rules

The Competition Arena Graphic aid for explaining competition goal

Feasibility Assessment Where Are We? Conceptualization Research Completed Numerous navigation and harvesting systems were researched and considered Other team’s solutions were researched Ideas were discussed and debated in a team environment Feasibility Assessment Analysis Completed Based on research, the team decided to proceed with a wheeled chassis using an excavation system based on the mechanical design of a snow blower. Preliminary Design Ongoing Certain systems, such as the excavation system, have been designed Electrical and software systems still in development Positioning system still in development Fabrication & Testing A “test platform” has been developed for testing of software and mechanical systems. This platform is close to completion. Final Lunabot fabrication is to be completed Bring audience up to speed on what has been done and what is yet to be done…Lead into the need for a positioning system.

Importance of the Positioning System Bonus points are given to teams with excavators capable of operating autonomously. 500 bonus points awarded to teams with excavators that complete the competition with no human interaction other than starting and stopping the excavator. The size of this bonus is substantial enough to be a deciding factor for winning the competition. To operate autonomously, the excavator must have a method of determining position within the competition arena. Position acquisition must occur quickly 1Hz or faster Must be able to determine position within region approximately the size of a tennis court, accurate to 10cm or less. Excavation process must not interfere with position acquisition

Proposed Positioning System Determine excavator position using triangulation with two rotating Doppler radios. Two Doppler radios are attached to the Lunabin Radios transmit directional/reflector angle Receiver on excavator records reflector angle and signal strength Signal strength “peaks” when reflector is pointed directly at excavator By determining when signal strength rises above a threshold, excavator can determine angle to each radio Triangulation can be used to determine position within arena To the best of our knowledge, no other team has used radio positioning—this is a unique and original concept for the Lunabotics competition

50 degrees 75 degrees 100 degrees 125 degrees 50 degrees 75 degrees 100 degrees 125 degrees Lunabin Transmitter Transmitter Robot

Receiver Example If threshold is signal strength of 6 Angle Signal Strength @1 Signal Strength @2 50 4 2 51 5 52 6 53 7 3 54 8 55 56 57 58 59 60 61 62 63 If threshold is signal strength of 6 Transmitters 2 meters apart Angle to #1 is (52+56)/2 = 54 Angle to #2 is (56 + 60)/2 = 58

Proposed Hardware Receiver (on excavator) Doppler Radio Atmel RZ600 Use spinning directional antenna Hardware to be determined

Software & Positioning System Integration Radios Positioning System PC Use MATLAB to determine excavator position and direction within arena Send position and angle to MCU via serial Remote Operator Sends stop and start commands Monitors system health Control excavator (if necessary) MCU Interpret position data from PC Use data to control mechanical systems Monitor basic system status (power usage, battery life, etc.) Report system status to operator Mechanical Systems (drivetrain, excavator, hopper, etc.)