Fall 2016 Biped – Updated Requirements #5

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Draft 5

By: Brandon Perez (Missions, Systems, and Test Engineer)
Approved by: Ijya Karki (Project Manager)

Table of Contents

Introduction

Included is the post CDR updated requirements with an explanation of the quantitative values used.

Level 1 Requirements

  1. Shall be ready to participate in the game “Save the Human” on December 14th, 2016.

Comment : The date is determined based off the class schedule and semester duration.

  1. Shall not exceed a cost of $125 to construct.

Comment : The budget has been determined by the customer.

  1. Will use a 3Dot board, have a custom-built PCB, and utilize the I2C interface.

Comment : These required items in our system have been set by the customer.

  1. Shall be able to walk a minimum speed of 5mm/sec to effectively maneuver the arena.

Comment : The speed has been determined based off the game arena dimensions, game duration, and the length of the typical expected path.

  1. Shall be able to turn within 30 – 90 degrees to the left side and right side.

Comment : The turn angle interval has been set for the Biped to have effective turning capability when navigating the maze. The servos provided to us have mobility from 0 degrees to 180 degrees. If a turn command sets the Biped to turn at 180 degrees, then it will turn 180 degrees from where it is facing. This feature will help the Biped turn directly to the opposite direction to improve it’s agility in the game.

  1. Shall be controlled telepathically up to 20ft (TBR) away through the Arxterra App. on a mobile device.

Comment : The distance has been determined since we expect to be sitting about 20ft away when operating the Biped during the game, “Save the Human”. The distance is yet to be determined by the game committee.

  1. Shall have a mass less than or equal to 450 grams.

Comment : The mass has been determined by our Servo Axial Load experiment conducted by our Electronics and Controls engineer.

  1. Shall be able to detect color pads in the arena of red, blue, and green color.

Comment : Colors have been selected because they are easily distinguishable from each other by the Human Vision System (HVS) when displayed on an RGB LED.

  1. Shall be able to operate for a minimum duration of an hour.

Comment : The minimum operating duration has been set by the customer.

  1. Should be able to walk on inclines and decline having max angle deviations of (+/-)6.5 degrees.

Comment : The minimum incline and decline deviation level has been set by the customer.

  1. Should be able to walk on uneven surface heights of 0.5 cm.

Comment : The uneven surface height level has been set by The Game Committee.

 

Level 2 Requirements

 

  1. Shall have a DC motor that can operate effectively at 5V and produce a torque of [TBR] to effectively move the Biped’s legs.

Comment : This voltage rating for our DC Motor has been set because the 3Dot motor driver provides 5V. The torque rating has been set buy the minimum amount of torque required to move the legs.

  1. Shall have a servo that can operate effectively at 5V and produce a torque of [TBR] to effectively lift the Biped’s arms.

Comment : The voltage rating for our servo has been because our External Power Supply with provide 5V. The torque requirement for the servo has been set by the minimum amount of torque required to shift the center-of-mass from foot to foot.

  1. Shall use a rotary encoder to provide data regarding the shaft position and help effectively keep the leg-movement system in synchronous with the arm-raising system.

Comment : This requirement has been set so the MCU knows when our Bipeds legs have finished taking a step (half a revolution or 180 degrees) so it can stop the DC motor and shift the center-of-mass before taking the next step.

  1. Shall have a servo at each ankle capable of turning the Biped’s mass of [TBR] between 30-90 degrees while the Biped is standing on one foot.

Comment : The servos being used at the feet of the Biped have been provided to us at no cost by the customer.

  1. Shall be able detect color pads with a color sensor and display the output onto an RGB LED.

Comment : We have chosen a I2C compatible color sensor to be able to detect the color of the floor pads when walking over them.

  1. Shall use an IMU to detect incline levels and correct its center-of-mass when walking on inclines and declines of (+/-) 6.5 degrees.

Comment : We have chosen to use an IMU to sensor inclines an declines since it was provided to us at no cost by the customer.