Dakarai (Project Manager)

Jeffrey (Electrical)

Fabio (Mechanical)

Hien (Software and Systems)

Project Objective

NASA's Planetary Science division has decided to send another exploration robot to Mars. After the Curiosity rover’s final mission, NASA seeks to explore the terrain of Mars from the perspective of our pioneering astronauts. To test the density and irregularity of the planet’s surface, the robot to be sent is a bipedal robot. This robot will be capable of covering traverse terrain that the previous rovers were unable to acclimate to. Additionally while simulating the actions of an astronaut, this new robot will be testing the bounds of mobility and different modes of locomotion whilst completing its mission of finding geographical locations on Mars.

This new robot will be named MicroFOBO.

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Mission Profile

To demonstrate the effectiveness of this prototype’s maneuverability, MicroFOBO will need to complete 3 trials. In our first trial, the robot will demonstrate the ability to walk and turn autonomously. This is a test of hardware functions and the robot’s systems. The second demonstration will simulate a live test from the ground. MicroFOBO will be tested to on its reaction to delay. During this time, the robot will be prompted to walk forward, turn right and turn left and will be assessed on its subsequent responses. The final trial will consist of testing its ability to walk on it's own. The robot will locate and approach plaques which represent the geographical locations on the surface of Mars.

Functional Requirements

L1.1 MicroFOBO will look cool

L1.2 MicroFOBO will respond to the direction prompt on the Arxterra App by initiating a turn sequence or walk sequence

L1.3 MicroFOBO will stop and stand when the forward button is not being pressed

L1.2 MicroFOBO shall be able to transition from walking to turning to standing without falling.

L1.5 Plaques will be placed within 4 ft to 6 ft from MicroFOBO's initial position.

L1.6 MicroFOBO shall use a platform which can complete a perigonal scan.

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L1.7 MicroFOBO shall be able to map surroundings by detecting from 4 to 6 plaques.

L1.8 MicroFOBO shall walk forward 1 m when there are no obstacles in front of it.

L1.9 MicroFOBO shall stop and stand when it has reached within 25 cm of a plaque.

L1.10 MicroFOBO shall complete a predefined turning sequence once it has encountered a plaque.

L1.11 MicroFOBO should display TBD locomotion techniques (e.g. walk backwalk, moon walk, shuffling, and striding).

Performance Requirements

L2.3.1 MicroFOBO shall use a custom 3 DoT shield designed for 8 servos, 1 Lidar and 1 stepper motor.

L2..1 MicroFOBO will use the ArxRobot application's joystick function to control forward and turning movements.

L2.7.1 MicroFOBO shall utilize a Lidar sensor to map the surrounding plaques.

L2.7.2 MicroFOBO shall use a stepper motor to map it's surroundings.

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Constraints and Engineering Standards

L1.1 This project will/shall be constrained to a cost of $450.

L1.2 This project shall be completed by May 8th, 2020.

L1.3 Firmware programs will be written using Arduino De Facto Standard.

L1.4 – MicroFOBO shall incorporate the 3DoT v9.05 or v9.1

L1.5 – MicroFOBO shall contain one custom-designed 3DoT shields.

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L1.6 MicroFOBO shall be in compliance with the 3DoT Command Telemetry Packet specification.

L1.7 MicroFOBO shall be controlled via Bluetooth 4.0 in compliance with the Bluetooth Special Interest Group (SIG) Standard.

L1.8 MicroFOBO will be constrained to a cost not to exceed $500.

System Block Diagram

• Arxterra Phone App
• Bluetooth Module is attached to the 3DoT Board which is controlled by the Arxterra App.
• The custom shield contains a CD4017, Lidar, External Power Supply, and connectors to provide the Stepper with power.

Project/Recovery Planning

How do we continue?

V2

• Individual research, assembly and testing
• Online troubleshooting
• Online demonstration

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V3

• Supplemental research
• Individual contribution to blogspot
• 2 units for demonstration

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Updated Conceptual Operations

Work Breakdown Structure

Product Breakdown Structure

Subsystem Design

Software Design

-Application Customization: ArxRobot

-Firmware Customization

Firmware used:

• “Servo_centering” to manually calibrate fobo.
• “Remote_control” and “FOBOPoser” program to calibrate and creating action files. These action files can be exported into arduino codes.

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V1 firmware:

• Implementation of ultra sonic sensor
• Detects and avoid obstacles

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V2 firmware:

• Uses 3dot and Arxrobot App
• Key functions and variables:
• Loop function
• moveHandler
• currentAction
• UpdateAction

V3 firmware:

• Work in progress
• Lidar module that scans surrounding environment
• Actively looks for objects

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Electrical Design

• Lidar is connected to the SDA/SCL pins on the Uno.
• Stepper is connected through four digital pins of the Uno.
• A CD4017 IC chip controls to the 8 servos.
• An external power source(battery) powers the servos to prevent stuttering.

EagleCad

• This is the schematic for the PCB of the ServoShield that will be fabricated and attached to the 3DoT Board.
• The difference between this generation and the previous generation of MicroFobo is the lidar, stepper motor, and the connections for the external battery.

Custom Shield Design Early Versions

Power Planes

Red - Positive Voltage External Battery

Blue - Ground

First Version

No DRC verification

No Power Planes

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Custom Shield Design Final Version

Power Planes

Red - Positive Voltage External Battery

Blue - Ground

Final Product

Verified under SparkFun Design Rules

Mechanical Design

Upper Half

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• Optimized head size
• Neck with stepper notch
• Lid with opening for stepper
• Housing for 3Dot, Stepper

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Mechanical Design

Continued

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• Hip Joint Secure both halves
• Servos bands and wraps
• Leg bracket to secure together
• Extension of Fobo foot

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Fully Assembled Fobo

Allocated Mass/Power Reports

Trade Off Studies

• Voltage within the range of external power
• Size is relatively small compared to the other motor
• Degree angle allows for accurate data acquisition
• Price is reasonable for the degree of rotation

Trade Off Studies Continued

• Lidar is lightweight
• The max range of a lidar is great
• At closer distances lidar data is not as accurate
• Lidar acquires data faster than an UltraSonic

Cost

Thank you!