Spring 2017 BiPed Preliminary Project Plan

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Alexander Clavel – Project Manager

Jacob Cheney – Missions, Systems, and Tests

Abraham Falcon – Electronics and Control

Mikaela Hess – Manufacturing and Design

Phong Nguyen – Manufacturing and Design

Table of Contents

Work Breakdown Structure (WBS):

By Alexander Clavel (Project Manager)

Figure 1: WBS

The Work Breakdown Structure shows the responsibilities and tasks of each member of the team. It breaks down the individual tasks and specifies exactly which division and or person it falls under. Figure 1 shows the breakdown for the BiPed Project. The structure was derived from working with the level 1 requirements previously established, the product breakdown structure, as well as the different design innovation methods we used. To set specific tasks, we had to look at what had to be done on the product as well as what we could do. These can all be referenced to the Spring 2017 Preliminary Design Document that was completed previously.

Project Schedule:

Top Level & System/Subsystem Schedule:

Figure 2

Figure 3

The project schedule gives a timeline overview of the work that needs to be done and it what time frame it needs to be completed in. Figure 2 depicts the top level schedule and the entire timeline of the BiPed project. The schedule is broken down into 4 phases which include planning, design, assembly, and project launch. The planning phase mainly consists of research required for the project as well as coming to a clear definition of the mission objectives. After the planning phase comes the designing of the BiPed. Considering that a BiPed has yet to be built using DC motors, this is proving to be a difficult part of our engineering process. Assembly comes next with project completion and project launch in conclusion.

In Figure 3 the schedule is broken down even further to specify tasks for each individual. These tasks can be traced back to the Work Breakdown Structure and include purchasing components to modeling and prototyping. Some of these jobs are ongoing throughout the project while some have specific deadlines that need to be met.

Burndown and Project Percent Completion:

Figure 4

Figure 4 is a representation of our progress by percent. The vertical axis is a measurement of the percentage of tasks that need to be completed while the horizontal axis is the number of weeks. The blue line is the ideal percentage of work that should be done while the orange line is the percentage of work that we have actually done so far. We fell behind in the beginning in terms of tasks that need to be done but we were able to make up about 30% of the work. Most of that work is still currently in progress and not yet complete.

System Resource Reports:

By Jacob Cheney (Missions, Systems, and Test)

The Mass Report shows the weight of each individual component of the system and the total of all of them combined. For some of our parts, we looked at previous semesters to get a better approximation of how much some of these components weigh. Others were found elsewhere on the web or measured by the manufacturing engineer. For the entire system, our initial calculations of the Total Expected weight came out to 392.95 grams. This lead to a Total margin of 145 grams and a Contingency of 152.05 grams.

The power resource report shows the division of current throughout the Biped system. Current estimates for each component are based on their respective datasheets. Our calculations for the total expected current came out to be 1150 mA. This left us with a total margin of 610 mA and a contingency of 660 mA.

Project Cost Estimate:

The Cost Report lists all of the parts and materials needed along with the purchase price for each. The Total Expected Cost for everything came out to $180.50 with a Total Margin of $54 and a contingency of $73.50.

Spring 2017 BiPed Preliminary Design Document

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Table of Contents

The BiPed Team:

Alexander Clavel – Project Manager

Jacob Cheney – Missions, Systems, and Test

Abraham Falcon – Electronics and Control

Mikaela Hess – Manufacturing and Design

Phong Nguyen – Manufacturing and Design

Program Objectives/Mission Profile:

By Alexander Clavel (Project Manager)

The customer has asked for a 7th generation robot that will be able to walk with the use of DC motors in replacement of servos. Based on the request of the customer, the bipedal robot will participate in the “end of semester” game. During the game, the robot will do battle with the velociraptor while using video support that is provided by the spider bot and pathfinder rover. With live video feed, the biped will be controlled with the Arxterra phone application to complete its mission.

Spring 2017 Requirements:

Project: Level 1 Requirements

By Alexander Clavel (Project Manager)

  1. The biped shall be able to achieve a static walk using dc motors.
  2. The Biped should be able to turn.
  3. The biped shall be able to participate in the “end of game” semester.

As stated by the customer

    4. The biped shall be controlled with the use of the Arxterra phone application.

As dictated by rules of the game

    5. The biped shall utilize a 3Dot board with custom SMD I2C shield.

As dictated by rules of the game

     6. The biped should be able to operate for an hour.

     7. The biped should be able to achieve dynamic walking.

     8. The biped shall fit within the classroom cabinets (size to be determined)

As instructed by the customer

     9. The biped shall be completed by the last day of class on Monday, May 15th, 2017.

As listed in the school schedule

MST: Level 2 System/Subsystem Requirements:

By Jacob Cheney (Mission, Systems, and Test)

  1. The BiPed shall have a Bluetooth v 4 .0 BLE Transceiver integrated circuit that will be able to communicate with an Android or iPhone.
  2. To maintain balance while static walking, the Biped shall use two servos as ankles to shift the center of gravity.
  3. The 3Dot Board shall receive commands from the Arxterra app via Bluetooth Transceiver. It will then decode and transmit data to the DC motors and servos.

E&C: Level 2 System/Subsystem Requirements:

By Abraham Falcon (Electronics and Control)

Abraham Falcon (Electronics and Control)

  1. The Biped will use two DC Motors for each hip for the walking movement.
  2. The Biped will use two Servo Motors for each ankle for a legs side movement.
  3. The Biped will use two Servo Motors for a turning movement.
  4. The Battery’s duration will last up to an hour.
  5. DC motor shall operate at 5 Volts for a static walk.
  6. Servo Motor shall operate at 5 Volts for a static walk.

Source Material:

https://www.arxterra.com/3dot/

M&D: Level 2 System/Subsystem Requirements:

By Mikaela Hess (Manufacturing and Design)

  1. The Biped will have a height restriction in order for it to fit in the closet with dimensions to be determined.
  2. The Biped will have legs designed to hold up the weight of a 3 dot board, Arduino, servos and the DC Motors.
  3. The Biped shall have an implemented design that makes the legs close together for better control of the center of gravity in order to achieve static walking.
  4. The Biped shall optimize the constant speed of the Biped for an hour by designing a leg that optimizes each length of each step in order to play the end of the semester game.
  5. The Biped should add an additional feature to the static design in order to achieve dynamic walking

Design Innovation:

Alexander Clavel ( Project Manager )

Through research of previous semesters requirements and final results, we developed our own areas of focus to create solutions for. Until now, most BiPed projects utilized servos to achieve walking, but ours will require the use of DC motors. As of yet, walking with DC motors has not been achieved so that has become our main area of focus. The Theo-Jansen approach gives us an initial approach to accomplish walking. Taking the “end of semester” game into consideration, the robot will also need to be balanced and be able to turn. Some ideas that were elicited from our creative exercises were to bring the legs closer in to allow for an easier shift in the center of gravity. Using the creative method, we devised different possible solutions for these problems.

Creativity Solution Slides

Systems/Subsystem Design:

By Jacob Cheney (Mission, Systems, and Test)

Product Breakdown Structure:

The product Breakdown Structure (PBS) is used to plan and display the outcomes of our project. The goal is to break down the product as much as possible to ensure nothing is overlooked. The hierarchical structure begins with the final product at the top followed by subcategorized elements below.

 

http://web.csulb.edu/~hill/ee400d/Lectures/Week%2004%20Modeling/e_Product%20Breakdown%20Structure.pdf

Good PBS Example (Velociraptor)

Electronic System Design:

System Block Diagram

The System Block Diagram shows the outputs for the ports of the DC motors, Servo motors, and the input for external power. The LDO 5V Regulator is used to increase the 3Dot board output voltage to the operating voltage for the Servo Motors. An Android or iPhone device with an Arxterra App will be used to control the Biped.

Source Material:

Fall 2016 Biped – Updated System/Software Block Diagrams  

 

Interface Definitions

 

Mechanical Design

By Mikaela Hess (Manufacturing and Design)

Pictured above is the initial idea that the Manufacturing engineers have designed. As can be seen above, we have the DC motors moving in the center of the body of the biped in order to have better control of the center of gravity. To make this happen, we must create a distance between the two DC motors large enough so that the two servos sized feet can be picked up and land onto the ground without disturbances. To go without the disturbances, we must create a distance of one servo between the DC motors, and an additional ⅕ of an inch of room to adjust for human error. Next, we placed the body on top of the DC motors, facing the other way in order to counteract the weight of the DC motors on either side, for better stability. This idea of having a long body was actually created from the Creative Project, where we forced a truck onto our biped design. The overall size of this Biped is to be under 10 inches. The body of the Biped is expected to be no more than 3 inches and the servo on the feet are expected to be no higher than 1 inch. With those calculations and the 1-inch radius in which the leg is designed to move around, the actual leg is to be designed in a total of 4-5 inches.

The actual walking of the biped is broken down into 5 steps here. In order to follow this design, the pictures are color coded according to the design’s components. In blue we have the representation of the circular path created by the DC motor and the pink segment. The pink segment is a sturdy piece of material that is directly linked to the DC motor and has a loose joint connection to the leg of the Biped, or the yellow piece in the picture above. Both legs start off in position one where the legs are bent and at rest at x and y equal zero on a radian circular graph. One leg then shifts its weight over by moving the leg over at an angle theta from resting position to the side by a servo. Once that is done, the DC motor then turns on and moves the pink segment to the negative pi over two positions on the same radial circular graph. This makes the body shift upward and lifts the other leg along with the body. After the segment goes to negative pi over two, it will move to pi on the radian graph, the ankle with resume its original position, causing the biped to take a step and then the legs will be programmed to reach equilibrium and resume its original position. Once that happens, the other leg repeats the same process and vice versa. Overall, the Biped should walk.

Once this design was created, I sent more photos and information to a Michael Oran Tobin, a Control Systems Engineer for California with PE Certification #CS7494. Once I had explained the servo use and parameters of the total design, it was made clear that my design would fail. What I failed to notice was the joint at the knee and the segment (yellow and pink where they connect), was that because there was no control onto that joint that the body could give out. As well, my design required precision that only DC motors with rotary encoding. A recommendation was made to use either a memory wire that straightens when current is given and loosens when there is none, or to use a servo at the knee for better control. The servo at the knee was decided to be a better option due to the memory wire being in early production and may not be able to handle the weight of the servo and leg. After going over the entire design, Michael Tobin strongly recommended doing more research on how humans walk and to consider how humans move their feet towards the center of gravity line to walk and then moves outward for better balance. As well, he suggested using a second wheel for better control of the joints. These pictures and ideas are pictured below and were made by Michael Tobin.

Overall, the design needs to reconfigured. More servos and research need to be done in order to create a working and walking Biped. The difficulty in this task is that most designs for biped are made using solely servos or stepper motors, which means this Biped leg design has to be made from scratch, but with help from other engineers and more research, it should be made possible. Also, a discussion with the project team and customer should be set up in the near future to discuss the use of more servos or motors.

Mechanical Design (Continued)

By Phong Nguyen (Manufacturing and Design)

This picture shows us a biped design based on human structure (hip, knees, and feet). As shown above, we decided to design the Biped with two DC motors for each hip, two servo motors for each ankle, and two Servo Motors for a turning movement. The DC motors are responsible for lifting up the whole leg while the servo motors will be used to shift the center of gravity. If we want to turn left or turn right, the servo motor at ankle will be able to accomplish that like last semesters biped. Under the foot, we will use high friction material such as sandpaper, rubber, or plastic. 

http://robogames.net/symposium/2007/07-108-Vaidyanathan-AnnaUniv-AnalysisofBipedalWalkingRobot.pdf

http://embeddedprogrammer.blogspot.com/2012/08/simulation-of-humanoid-robot.html

Design and Unique Task Descriptions:

Electronics and Control

By Abraham Falcon (Electronics and Control)

Biped Electronics and Control Design Process/Analysis

According to 3Dot Board specifications, it only supports 5V Turbo Boost for driving DC motors and for the Servo Motors to be operated at 5V. Using a rated 12V DC Motor to be power at 5V to measure the current draw at no load conditions and stall current to know the maximum current the motor will use to determine the Biped Battery total current it can supply. Also, for a Servo Motor to be power at 5V to measure no load current and stall current to determine the maximum current it will draw to know what battery is needed.

 

Biped Electronics and Control Tasks

  • Choose DC Motors to be compatible with the 3Dot Board’s TB6612FNG Dual Motor Driver.
  • Choose Servo Motors to be compatible with the 3Dot Board’s Two 3.7v Micro and Ultra-Micro Servo ports using a Voltage Regulator.
  • Perform Trade-Off Study on DC Motors to select for Biped for the 3Dot Board.
  • Perform Trade-Off Study on Servo Motors to select for Biped for the 3Dot Board.
  • Do Servo Motor Analysis to know what are the specs on a load condition on the Servo Motor and know how much mass it can handle at its maximum current.
  • DC Motor Analysis to determine the maximum current under a load condition and know what is the maximum mass it can handle.
  • Measure all currents of the motors to know the total current for the Biped Battery’s Specifications.
  • Select a Power supply that will handle all the current that the motors are consuming.
  • Create a Fritzing Diagram and test it on a breadboard to assure its properly working.
  • Use Eagle CAD to create an electrical schematic (PCB).
  • Using Arduino IDE to program the DC Motors and Servo Motors to work properly and to be successful.

Source Material:

Fall 2016 Biped – Updated Schematics  

http://arxterra.com/goliath-fall-2016-preliminary-design-documentation/

Manufacturing and Design

By Mikaela Hess (Manufacturing and Design)

Manufacturing Tasks

  • Measure the cabinet’s height and reduce it by one inch and make that the height requirement (so there is room for error).
  • Perform Trade-Off studies to see what implemented structures are used to make a robot walk using DC motors.
  • Weigh out the servos and DC motors, 3 Dot Board, and Arduino to know the total weight capacity.
  • Design a foot that has better grip and curvature for a smoother transition in steps.
  • Perform a Trade-Off study to see what materials are the lightest and sturdiest material to handle the weight.

 

Biped 2016 Fall – Final Documentation

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Introduction Project Overview

Project Objective

Team Biped will produce a two legged 6th generation toy biped robot that will replace the traditionally used servos with a dc motor and achieve static walking. By utilizing the 3Dot Board, the robot will participate in the end of semester, December 14th, 2016, game called: Save the Human.

Mission Profile

Biped shall compete, alongside other toys such as Goliath and Velociraptors, in an end of semester approximately hour long game: Save The Human. Biped should successfully walk, using Goliath’s live video feed as the field of view, from the opposite end of the room to the finish area without coming into contact with a Velociraptor. The Biped will  maneuver through multiple obstacles by turning through walls, sensing color pads, and stepping through uneven terrain placed on top of Linoleum floors.

build4

Project Features

A key component of our design is replacing the ankles with servos. The ankle servo eliminates having to use two dc motors to accomplish a pivot turn. The placement of the servos provides a strategic way to balance on on foot and then turn the entire body to face the desired direction.

 

turning

Requirements

Fall Biped 2016- Quantitative Values for our Requirements

System Block Diagram

Fall 2016 Biped – Updated System/Software Block Diagrams

Interface Definition

Interface Matrix and Cable Tree

Fall Biped 2016- Interface Definition and Cable Tree

 

Mission Command and Control

Software Design

Fall 2016 Biped – Updated System/Software Block Diagrams

Arxterra App Communication

Fall 2016 Biped – Arexterra Control Panel

Custom Commands

custom-comands

Electronics Design

Component Selection and Trade Off Studies

Fall Biped 2016- Motor and Battery

Electronic Experiments

Fall 2016 Biped Experiment- Ankle Servo

Fall 2016 Biped – Color Sensor Experiment

Fall Biped 2016- Updated Stall Current Motor Experiment

 

Firmware

Fall Biped 2016- Software Structure

Fall 2016 Biped – Code/Software Update

PCB Schematics

Fall 2016 Biped – Updated Schematics

Fall Biped 2016- Color Sensor Design

Fall Biped 2016- Hardware Alternative Updates

PCB Layout

Fall 2016 Biped – PCB layout

lay1

lay

Hardware Design

Fall Biped 2016- Design Document

Fall Biped 2016- Foot Design

Fall Biped 2016- Shifting Center of Mass to Achieve Walking

Hardware Experiment

Fall Biped 2016- Ankle Stress Test

Hardware Selection – Trade Off Studies

Fall 2016 Biped Material Trade-Off Study

Fall 2016 Biped Trade Off Study- Ankle Servos

 

Verification and Validation Test

Fall Biped 2016- Verification Matrix and Validation

Project Status

Updated Mass and Power

Fall 2016 Biped – Updated Mass and Power Allocation

Cost Report

 

Vendor Item Unit Price Quantity EE Dept. /Total EE Dept. Extended Cost
1 LOWE’S Miscellaneous Hardware 54.31 54.31
2 Mouser Electronics 27.82 27.82
3 Pololu Hardware (Motor/Gearbox/ Wires) 9.55 9.55
4 Hobby People Electronics (Battery/ Connectors) 16.33 16.33
5 Oshpark Color Pad PCB 0.60 0.60
6 Oshpark Shield PCB 20.45 20.45
Total: 129.05
Allocated Budget 125.00

Schedule and Burndown

Fall Biped 2016- Schedule and Burndown

Resources

[1] Project video

[2] PDR

[3] CDR

[4] Eagle Design

[5] Biped Code

[6] Solidworks 

[7] Animation/ Simulation

[8] PCB layout

Fall Biped 2016- Hardware Alternative Updates

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By: Alan Valles (Electronics and Control)
Approved by: Ijya Karki (Project Manager)

Table of Contents

Introduction

The purpose of this document is to provide suggestions for the next iteration of the design of the PCB shield for the Biped. These improvements are based on feedback and experience in the manufacturing, design and build of the PCB.

Analysis

The engineering method is an iterative process. There are several suggestions and improvements that can be made to Biped schematics in [2]  to improve performance of the system.

The Schematics since CDR were not revised much. However, after the realized PCB system was put together and tested, there are several updates that I would make for the next revision of the shield. I would add pin headers for the I2C bus. This would allow for flexibility in future iterations for the Biped Project. In the future, I also would have changed the design to incorporate locking headers like the Ph-series of battery and motor connectors for the rest of the external peripherals. These will allow for more secure connections. The combination of jumper wires and pin headers was not a fixed connection and caused major amounts of headache due to contacts not connecting. It lead to perplexing troubleshooting in order to see if bugs were software related or hardware related.

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Figure 1. Circuit System.

Next, I would add a protection circuit to prevent reverse current in the event of reverse polarity. The chosen lm1084 does not have this built into it. However, the battery was hooked up with reverse polarity the first time. The LM1084 was a robust chip because after reversing polarity of input the LDO still held up fine and output 5V to the rest of the systems. TI offers some quick suggestions to mitigate this issue, by using a protection diode or FET as shown.

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Figure 2. NMOS FET in the Ground Return Path.

Next, The Ext- connection was not solidly grounded on the PCB, rather it created a GND connection on the 3Dot board itself. To correct this issue, traces and or vias to GND plane can be created near the connector of the Battery for stronger connection to GND. Finally, another issue was that 3.3V and Ext+ were being paralleled on the PCB that was ordered. After discussion and analysis, the president and I were able to fix this by isolating the connecting point by cutting a copper trace. The GND connection on the shield was never connected to EXT- connection on the 3dot. A small wire was post manufacturing. But the future shield should tie these point together at some point.  Also the SDA and SCL lines were crossed for A2D converter so that would obviously be fixed in next iterations.

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Figure 3. After PCB in Production.

These are some of the changes that were recognized after our PCB was in production that should be fixed for the next iteration.

Conclusion

In conclusion, the pin headers for encoder connector, and other external peripherals would be changed to a locking style, a reverse current protection circuit would be added and various clean up work would be done such as tying GND to Ext-.

Reference

[1] http://www.ti.com/lit/an/slva139/slva139.pdf

[2] http://arxterra.com/fall-2016-biped-updated-schematics/

 

Fall Biped 2016- Color Sensor Design

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By: Alan Valles (Electronics and Control) Approved by: Ijya Karki (Project Manager) Table of Contents Introduction  The purpose of this blog post is to explain the function and design of the custom PCB color sensor that was made. Analysis This color sensor was made to meet our requirements and detect color pads below. Two version […]

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Fall Biped 2016- Verification Matrix and Validation

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

Req. No. “The Biped Shall” Statement Success Criteria Method Results Pass / Fail

Introduction

This report covers the Test Plans for Verifying and Validating our Requirements.

Matrix

L1-1 Shall be ready to participate in the game “Save The Human” on December 14th, 2016. The project must be fully functional and presentable by December 14th, 2016. Demo FAIL
L1-2 Shall not exceed a cost of $125.00 to construct. The project must not exceed a budget of $125.00. Inspect PASS
L1-3 Will use a 3Dot board, have a custom PCB, and utilize the I2C interface. The project must contain a 3Dot board as the main control unit for the system, have a custom-built PCB, and utilize the I2C interface on the 3Dot board. Inspect PASS
L1-4 Shall be able to walk a minimum speed of 0.32mm/sec. The Biped shall have to walk a straight path at a speed of 0.32mm per second. Test FAIL
L1-5 Shall be able to turn up to 180 degrees on each of its sides. When the Biped is initiating a turn, the angle that it turns its body shall be any angle ranging from 0-180 degrees. Test PASS
L1-6 Shall be controlled telepathically up to 20ft away through the Arxterra App. When controlling the Biped via Arxterra Control Panel on a mobile device, the Biped shall be able to be controlled up to 20ft away from the user. Test PASS
L1-7 Will have a mass less than or equal to 750 grams. The total Biped’s mass shall not exceed 750 grams. Test PASS
L1-8 Shall be able to operate for a minimum duration of 1.00 hour. The Biped system shall have to operate for a minimum duration of 1.00 hour Test PASS
L1-9 Should be able to walk on angled surfaces with max slope of (+/-) 6.5 degrees. The Biped should be able to walk on inclines of 6.5-degree slope and declines of -6.5-degree slope. Test FAIL
L1-10 Should be able to walk on uneven surface heights of 0.5 cm or less. The Biped shall remain stable when walking over obstacles spread over the ground which shall have heights ranging from 0 mm to 5 mm. Test FAIL
L2-1 Will have a DC motor that can operate effectively at 5V and produce torque of 9.75e-3 ft*lbs. The DC Motor shall have an operating voltage of 5V or greater and shall have to produce a minimum torque of 9.75×10^-3 ft*lbs. Test PASS
L2-2 Will have servos that can operate effectively at 5V and horizontally move a mass of 68g. The servos being used to control the Bipeds arms shall have an operating voltage of 5V or greater and shall be able to turn horizontally the Biped’s arm’s mass of 80g. Test PASS
L2-3 Will have a rotary encoder to read the shaft’s position at a rate of 40 times the Motor RPM. The shaft encoder shall give a reading of the shafts position at a minimum rate of 40x[Motor RPM] to ensure the MPU has a resolution Test PASS
L2-4 Shall use an RGB LED to display the color of the color pad for a minute duration. When the Biped steps on top of the color pads, the color of the pads shall be displayed on the RGB LED for a minute duration. Test PASS
L2-5 Should have an IMU to detect inclines and decline angle deviations up to (+/-)6.5 degrees. The IMU should provide readings of the angle deviation when the Biped is walking on angled surfaces for all angles between -6.5 and 6.5 degrees. Test FAIL
L2-6 Will use a battery with a capacity rated at 560mAh or greater. The battery for the system must be rated at a capacity of 560mAh or greater. Inspect PASS

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

Tools:

  1. Biped (final product)
  2. Calendar
  3. Clock

Procedure:

  1. If the Biped is complete, look at the calendar and record the current date.
  2. Look at the clock, and record the current time.
  3. Verify that the current time and date is before 9:30AM December 14th, 2016

RESULTS: By the time of final demonstration, the Biped was not able to walk. Our DC Motor Gearbox had gears that would constantly slip against each other causing our walk movement to stall at most times. In result, we did not meet the schedule requirement.

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Level 1 Requirement 2:
Shall not exceed a cost of $125.00 to construct.

Tools:

  1. Biped Expense Report

Procedure:

  1. Look at the expense report and record the total Biped expenditure.
  2. Verify that total expenditure does not exceed $125.00.

RESULTS:

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We have totaled $129.05 of expenses so we are $4.05 over budget. Regardless that we are over budget, we have still been within the customer’s contingency which is a reasonable 3.2% over budget.

13

Level 1 Requirement 3:
Will use a 3Dot board, have a custom PCB, and utilize the I2C interface.

Tools:

  1. Biped (final product)

Procedure:

  1. Inspect the Biped to verify a 3Dot board is being used when operated.
  2. Inspect the Biped to verify a custom-built PCB is being used when operated.
  3. Inspect the Biped to verify the I2C peripheral interface is being used when operated.

RESULTS: In the 3 pictures, below, we show 3 different perspectives of the of the 3DOT board and PCB encasement in our Biped.

The 3Dot’s board 12C peripheral interface pins are mapped to the custom built PCB for I/O access. Since we have a 3Dot board, a custom-built PCB, and are utilizing the I2C interface, this requirement has been met.

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In the 3 pictures, below, we show 3 different perspectives of the of the 3DOT board and PCB encasement in our Biped. The 3Dot’s board 12C peripheral interface pins are mapped to the custom built PCB for I/O access. Since we have a 3Dot board, a custom-built PCB, and are utilizing the I2C interface, this requirement has been met.

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Level 1 Requirement 4:
Shall be able to walk a speed of 0.32mm /sec.

Tools:

  1. Stop watch
  2. Measuring tape
  3. Biped with Arxterra Control
  4. Poster paper 3’x3’
  5. Marker
  6. String

Procedure:

  1. Mark the center point on the poster with the marker.
  2. Draw a circle of radius of 1ft around the center point using the string.
  3. Draw a radius on the circle.
  4. Place the Biped on the center mark made in step 1 facing the direction of the radius.
  5. Start a timer on the stopwatch and have the Biped operate its walking motion until it walks outside the circle and then stop the timer.
  6. Record the time it took for the Biped to reach outside the circle.
  7. Use V=D/T to determine the speed.
  8. Measure the angle at which the Biped walked with respect to the expected path to determine how straight the Biped walked.

RESULTS: Unfortunately, our Biped was unable to walk without falling over. To point out the obvious issues, too much mass had been concentrated in the front of the Biped which caused it to fall frontward. For improvement up our design, we should extend the feet out by about 1cm.

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Level 1 Requirement 5:
Shall be able to turn 180 degrees on each of its sides.

Tools:

  1. Protractor
  2. 8”x11” white paper
  3. Marker
  4. Biped with Arxterra Control

Procedure:

  1. Place the Biped on top of the center of the White 8”x11” sheet of paper.
  2. Use the marker to draw a line directly out from where the Biped is facing on the white sheet of paper.
  3. Initiate the Biped to turn at angles ranging from 30 to 180 degrees in increments of 30 degrees. With each new turn, the Biped should be replaced facing its original direction.
  4. With each turn implemented, draw lines out from where the Biped is facing on the paper when it is in its new facing position.
  5. Determine how accurately the Biped performed the turns by measuring the angles of each of the lines with respect to the original position.

RESULTS:

We began this test by initiating a turn on the Biped when it was standing on one leg.

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The Biped was able to take a turn here of 44 degrees when standing on one leg. The turning requirement was set to be accomplished when walking, however we were able to independently turn without ever be in the walking motion, therefore this requirement has been met to some degree of turning, literally.

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Level 1 Requirement 6:
Shall be controlled in RC mode in the Arxterra App up to 20ft away.

Tools:

  1. Measuring Tape
  2. Biped with Arxterra Control Panel on Mobile Device

Procedure

  1. Start the experiment by initiating a custom command to the Biped at 2ft away.
  2. Make sure no obstacles are in the way when sending commands and repeat the process by moving 2ft further each time until the Biped does not respond to the commands being sent.
  3. Record the distance at which the Biped did not respond to the commands from the mobile device.
  4. Verify that the distance recorded is greater or equal to 20ft.

RESULTS:

We began this test by setting up the Biped 20ft away from the user who was sending commands via Arxterra control.

17

Due to limited time, we had only tested directly above 20ft away. In the picture you can see the view of a tape measure being extended out to confirm we were at least 20 ft away from the Biped to meet the RC Mode requirement. We could confirm that our biped was still able to receive commands at 20ft away, therefore we met this requirement.

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Level 1 Requirement 7:
Will have a mass less than or equal to 750 grams.

Tools:

  1. Scale with accuracy of (+/-) 0.5g
  2. Biped

Procedure:

  1. Turn on the scale and set the reading value to grams (g).
  2. Place the Biped on the scale and read the value of the mass.
  3. Verify the mass does not exceed 750g.

RESULTS:

We begin by setting our Biped on the scale to determine its final mass.

18

The mass of the Biped is measured to be 466 grams. The mass requirement for our Biped is to be less than or equal to 750 grams, therefore this requirement has been met.

13

Level 1 Requirement 8:
Shall be able to operate for a minimum duration of 1 hour.

Tools:

  1. Biped
  2. Multimeter with current reading

Procedure:

  1. Measure the current drawn from the battery when the Biped is walking for the course of a minute.
  2. Determine the average current drawn from the battery over the minute duration.
  3. Verify that this value does not exceed the mAh rating on the system’s battery.

RESULTS: We begin the test by measuring the current drawn from the battery when the Biped is running the motor to produce its walking motion. We use an ammeter in series with the battery terminal and the DC motor pin. We recorded a video for a minute duration and then extracted the values from the ammeter throughout the video and provided them below.

We begin the test by measuring the current drawn from the battery when the Biped is running the motor to produce its walking motion. We use an ammeter in series with the battery terminal and the DC motor pin. We recorded a video for a minute duration and then extracted the values from the ammeter throughout the video and provided them below.

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Data Collected from Ammeter: [0.68 0.14 0.12 0.14 0.10 0.19 0.09 0.37 0.33 0.93 0.47 0.48 0.38 0.35 0.44 0.41 0.45 0.40 0.47 0.33 0.42 0.61 0.57 0.42 0.37 0.88 0.39 0.53 0.64 0.87 1.14 0.98 0.64 0.82 0.46 0.48 0.29 0.33 0.58 0.41 0.55 0.39 0.50 0.56 0.72 0.90 0.40 0.60 0.49 0.71 0.40 0.66 1.21 0.75 0.34 0.39 0.52 0.35 0.36 0.98 0.42 0.54 0.54 0.51 0.71 0.72 0.76 0.96 0.78 0.51 0.59 0.34 0.31 0.26 0.62 0.33 0.20 0.28 0.25 0.20 0.42 0.51 0.62 0.61 0.43 0.57 0.66 0.45 0.36 0.52 0.42 0.38 0.45 0.32 0.18 0.22 0.28 0.32 0.20 0.41 0.37 0.48 0.52 0.58 0.27 0.29 0.35 0.27 0.14 0.22 0.19 0.16 0.13 0.20 0.21 0.29 0.40 0.55 0.46 0.55 0.48 0.46 0.40 0.34 0.23 0.25 0.35 0.37 0.25 0.30 0.24 0.35 0.31 0.29 0.49 0.54 0.48 0.56 0.62 0.38 0.24 0.19 0.15 0.25 0.28]

I then proceeded to calculate the average in MATLAB.

20

Since our walking motion is our most energy expensive operation, we can assume that we walk the entire duration of the game to get the maximum energy expense throughout the entire game duration.

If we assume the Biped will be walking the entire game, (which in reality, it won’t) it would consume 440mA x 1hr = 440 mAh of energy from the battery. Since our battery can provide 800 mAh of energy theoretically, then our battery should have sufficient energy for providing power to the Biped for the entire game duration of an hour.

13

Level 1 Requirement 9:
Should be able to walk on angled surfaces with max slope of (+/-) 6.5 degrees.

Tools:

  1. Biped with Arxterra Control (final product)
  2. Ramp of 6.5 degrees

Procedure:

  1. Operate the Biped and have it walk up against the incline and verify it doesn’t fall over.
  2. Operate the Biped and have it walk down the incline (decline) and verify it doesn’t fall over.

RESULTS: Unfortunately, our testing and design had been narrowed and focused towards the walking portion of the design, so we disregarded testing on inclines. 

11

Level 1 Requirement 10:
Should be able to walk on uneven surface heights of 0.5 cm or less.

Tools:

  1. Biped with Arxterra Control (final product)
  2. Cardboard cutout 6”x6” of 0.5 cm thickness

Procedure:

  1. Place the Biped on the floor.
  2. Place the carboard cutout a couple of inches away from the Biped.
  3. Operate the Biped and have it walk towards the cutout.
  4. Verify that the Biped can walk over the cardboard cutout without falling over.

RESULTS: Unfortunately, our testing and design had been narrowed and focused towards the walking portion of the design, so we disregarded testing walking on uneven surfaces.

11

Level 2 Requirement 1:
Will have a DC motor that can operate effectively at 5V and produce torque of 9.75e-3 ft*lbs.

Tools:

  1. DC Motor
  2. String
  3. Water bottle
  4. Scale
  5. Ruler

Procedure:

  1. Measure the shaft Radius for the DC Motor being used on the Biped.
  2. Divide the torque required [9.75×10^-3 ft*lbs] by the obtained shaft radius to get the weight.
  3. Fill the water bottle with water till it weighs as much as the value obtained in step 2.
  4. Tie the string several times around the motor shaft until it does not slip off.
  5. Tie the other end of the string the water bottle.
  6. Power the DC motor against the edge of a table with the water bottle hanging from the shaft.
  7. Verify that the motor can lift the water bottle.

RESULTS: We have set our DC motor torque requirement in the units of ft*lbs for making our calculation easier. We proceed to measure the diameter of our motor shaft to determine its radius.

We used calipers to measure the DC Motor shaft diameter.

21

T = F*L

T = 9.75×10^-3 ft*lbs

L = 2.6mm/2 = 1.3mm

1.3mm = 0.0043 in

F = (9.75×10^-3 ft*lbs)/(4.3×10^-3 ft) = 2.26 lbs = 36.28 oz

Since our DC Motor is already rated at 5V, no test must be done for the first part of the requirement. As far as the torque requirement, the DC Motor was successfully able to lift the gallon of water up, therefore this requirement has been met.

22

13

Level 2 Requirement 2:
Will have servo that can operate effectively at 5V and horizontally move a mass of 68g.

Tools:

  1. Servos being used to control the Biped’s arms
  2. Servo shaft connector piece
  3. Small tray 3” diameter
  4. Water Bottle

Procedure:

  1. Place the servo with the shaft axis facing upright.
  2. Attach the servo shaft connector and place the tray on top of the connector.
  3. Make sure the tray is secure on top of the servo’s connector.
  4. Fill the water bottle until it weighs 68g.
  5. Place the water bottle on top of the tray.
  6. Operate the servo and verify that it can turn over its full range while having the mass over it.

RESULTS:

Since our servo is rated at 5V already, no test is necessary for the first part of the requirement. To check if our servo can horizontally move a mass of 68g, we set the servo upright and attach a platform to carry the several different masses.

 

23

It was found through this experiment that the servo could horizontally move the masses on top of the platform up to 400g. We concluded that we that servo could meet the requirement so we suspended further testing of heavier masses.

24

13

Level 2 Requirement 3:
Will have a rotary encoder to read the shaft’s position at a rate of 40 times the Motor RPM.

Tools:

  1. 3Dot Board
  2. Rotary Encoder interfaced onto the 3Dot board
  3. Rotary Encoder test code

Procedure:

  1. Run the test code for the rotary encoder.
  2. Be sure to have a serial communication from the 3Dot board to your computer to see the sensor values.
  3. Turn the potentiometer of the rotary encoder and verify that the sensor can read values at various positions.

RESULTS:

We began this test by timing how long it too our motor to turn its shaft a full 360 degrees under the load of the legs it must move.

25

Time per motor revolution: 11.71sec

26

MOTOR RPM = (60secs per min)/(11.71sec) = 5.12

Therefore, our rotary encoder must read values at a rate of 40×5.12 = 204.8 times/minute to get a sufficient resolution of the shaft position.

We then began to try and measure how fast our rotary encoder could take values so wrote an Arduino code to write a timestamp after every rotary encoder reading.

Our values being outputted at the computer for time are in units of milliseconds. If you look at the picture at the left, you can see that each of the time readings are spaced by 4 milliseconds.

Therefore the sample rate for our rotary encoders ADC is 60/(4×10^-3 Hz) = 15,000 times per minute.

This sample rate is clearly sufficient for our system, therefore this requirement is met.

Level 2 Requirement 4:
Shall use an RGB LED to display the color of the color pad for a minute duration.

Tools:

  1. 3Dot Board
  2. Color Senor interfaced with 3Dot board
  3. Color sensor test code
  4. RGB LED
  5. Red, blue, and green construction paper

Procedure:

  1. Interface the Color Sensor and the RGB LED with 3Dot board.
  2. Run the test code for the color sensor and have the sensor readings output to the RGB LED.
  3. Place the red construction paper near the color sensor and verify the LED lights up red.
  4. Place the blue construction paper near the color sensor and verify the LED lights up blue.
  5. Place the green construction paper near the color sensor and verify the LED lights up green.

RESULTS:

We began testing the color sensor by seeing if our sensor was reading values. We placed the Biped above 3 different colored construction papers of color red, blue, and green.

27

The above pictures show our Biped testing the color sensor on the foot. To determine if our color sensor was reading the values, we send the sensor values via seirial communciation to be displayed on our computer.

28

We were able to successfully distinguish the color of the construction with the data we were receiving on our monitor. Our color sesnor was sucessful, however we were not able to display the value on the RGB LED since our GPIO expander on our custom PCB was having issues.

Level 2 Requirement 5:
Should have an IMU to detect inclines and decline angle deviations up to (+/-)6.5 degrees.

Tools:

  1. 3Dot Board
  2. IMU
  3. IMU Test Code

Procedure:

  1. Interface the IMU with the 3Dot through the I2C peripheral interface.
  2. Run Test code for the IMU on the 3Dot.
  3. Be sure to have a serial communication from the 3Dot board to your computer to see the sensor values.
  4. Once code is running, tilt the sensor at various angles.
  5. Verify that the sensor responds well to all angles being tilted at.

RESULTS: Due to limited time, we decided to not include an IMU in our final design since it would require more testing and its effectives would only benefit us if our system had already passed walking.

11

Level 2 Requirement 6:
Will use a battery with a capacity rated at 560mAh or greater.

Tools:

  1. Battery being used for Biped

Procedure:

  1. Identify the Capacity in mAh for the battery being used on the Biped
  2. Verify that the batteries capacity exceeds 560 mAh.

RESULTS:

29

Our battery is rated at 800 mAh, therefore this requirement has been met.

13

 

Fall Biped 2016- Interface Definition and Cable Tree

/in , /by

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

Table of Contents

Introduction

This report will cover the interface definition and cable tree.

Table Information

1

Figure 1. 3DOT Interface Matrix.

On the top, here, we have our interface definition presented at CDR that has been updated to match our final Biped design. On the left, you can see the interface definition of the 3Dot board while on the right, you can see the interface definition for the 16-port GPIO expander that was included onto out custom-built PCB.

One of the changes that we made to the 3Dot interface was removing the second DC motor from the design. We worked with one DC motor to make design work. We attached both legs 180 degrees out of phase to the shaft output of our DC Motor gearbox.

On the GPIO expander, we removed the “body servo” which was supposed to helped shift the center-of-mass either in front of the Biped or behind the Biped when it would walk on inclines or declined, respectively. We omitted that servo because it was causing our Biped to weight up to 1kg with all the mass attached the servo.

 

Cable Information

2

Figure 2. Biped Cable.

Here on this image, we see the Cable tree which corresponds to the final design we have for the Biped. Since the “body servo” was removed, we have removed on set of cabling leading to one of the servos in the center of the figure right below the head. Our wire lengths and type for the servos correspond to the wires that our already on the servos. The cables for the servos are routed out of the head encasement and directly to the servos through a path between the legs. The wires for the color sensor that leads to the foot was the only set that was hand soldered and routed.

Conclusion

The interface definition and cable criteria are described above according to the design for the final Biped.

Fall Biped 2016- Motor and Battery

/in , /by

By: Alan Valles (Electronics and Control)
Approved by: Ijya Karki (Project Manager)

Introduction

The purpose of this document is to show all the updated schematic and hardware changes since CDR.

Hardware Design

The Final Hardware design of our robot was slightly different than what we had spec’d for CDR. The Motor stayed the same, it was a pololu 1117 size 130 motor. However, the gearbox that it went into was different. The final motor selected was the Tamiya 907710.[1] This motor was selected based on its gear ratio which was able to provide the Biped with even more torque than the previous model. Our Motor had an output RPM of m 11500 RPM at its shaft. We needed more torque due to the fact that our latest linkage design was larger/ longer than the previous design.  The Tamiya 70110 4-speed Crank Axle Gearbox Kit had 4 ratio option, 5402:1, 126:1,441:1 and 1543:1.

8

Figure 1. Speed Crank Axle.

These ratios dropped the output RPM to 2.2, 7.45, 27, and 16RPM respectively.

The only observed issue with this gearbox was that the gears internally seemed to be rubbing together when under large amounts of mechanical load. I noticed that there was an unsettling amount of play in the gears when it was put together.

10

Figure 2. Gearbox.

I suspect that once the load past a certain limit, the gears shifted to the left touched the high RPM green gear. This caused a clicking sound during random intervals of the walking motion.

Battery

9

Figure 3. Battery.

The battery was changed to a hobby people 7.4v 800mA Battery.[2] This battery was chosen over our previous battery because, we did not have to wait for shipping. Lithium batteries have a risk of catching fire which means that they are not shipped by air, only on trucks. Thus, it was much easier to go to the physical location of hobby people and purchase the needed battery and connector right on the spot. The form factor of the battery was absolutely perfect for our design as well. It had the dimensions of 12x35x68 mmm and weighted around 50g. Thus it was the perfect size for a RC Biped. Also, the pololu 117 motor had around 550mA operational current when attached to the 70110 gearbox. This was done by measuring it with a Digital Multimeter. Therefore, a rough calculation of power would be 650mA*5V = 3.25 W and the battery has a capacity of 7.4* 800mAH = 5.92 Wh. Thus, the battery still appears to meet our requirements that state we should play the game for an hour.

Conclusion

In Conclusion, The Battery and motor were changed to the hobby people 2S Lip and the Tamiya 70110 gearbox, respectively. This was done to increase the realized torque demand of the linkage assembly which was updated in order to meet customer request.

References

[1] https://www.pololu.com/product/68

[2] http://www.hobbypeople.net/index.php/hobby-people-7-4v-800mah-2s-30c-lipo-battery-bec-plug.html

[3] http://arxterra.com/fall-2016-biped-updated-motor-study/

Fall Biped 2016- Software Structure

/in , /by

By: Alan Valles (Electronics and Control)
Approved By: Ijya Karki (Project Manager)

Table of Contents

Introduction

The purpose of this document is to demonstrate software logic behind the Biped.

Analysis

The Fall 2016 Biped had a requirement which stated that the Biped had to be controlled using RC mode in the Arxterra App. The main feature of the app is a directional pad which is controlled by the Move Command. There is also a capability of adding Custom Commands. Electronics and System Engineers had several ideas and thought about the best way to utilize these. However, the backbone of our software and electronics subsystem design is a rotary position sensor. The selected rotary position sensor is the Bourns 3382. The rotary position sensor is a potentiometer that can spin forward up to 100000 cycles.[1]This means the inner rotor can be spinning freely.[1] All of the logic to be implemented is dependent on the readings of this value. As shown in the diagram below. The unsigned integer values between 0 and 1642. This value can be changed by setting the gain of the ADS1015 A2D converter in the set up loop. Therefore, logic can be implemented to control the robot in 330/360 of its walking motion.

3

Figure 1. Encoder Value

Thus, as the encoder value increases or decreases we continue to check to position and move the arms to the side of the foot that is planted. Ain0 shown in the picture above correlate to the variable adc0.

Poll a2d converter after every loop.

4

Based on position of walking motion i.e. shaft position, adjust arms accordingly.

5

Essentially when the user presses forward on rc mode in the move command, the robot will move and if the robot is on its left foot, the arms will move to left side and if on right foot, the arms will move to right side.

Also, the servohandler custom command was overridden to read color sensor and display LED using sx1509 gpio library. The final design was meant to use millis function inside loop as shown in reference [2]. It was commented out in the code that is uploaded to the zip file.

6

Conclusion

In conclusion, these are some of the code snippets for the Biped Group Design. Please see the Zip file for more information or our previous software blog post for library information.[3]

 

Reference

[1] http://www.bourns.com/pdfs/3382.pdf

[2] https://www.arduino.cc/en/Tutorial/BlinkWithoutDelay

[3] https://www.arxterra.com/fall-2016-biped-codesoftware-update/

Resources

[1] Biped Code

Fall Biped 2016- Quantitative Values for our Requirements

/in , /by

By: Brandon Perez
Approved by: Ijya Karki (Project Manager)

Table of Contents

Introduction

A final update of the requirements with completed values is provided below. The reason for preparing quantitative requirements is to ensure that during the validation and verification tests, we have more testable criteria.

Level 1 Requirements

The Biped shall statement…

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

-Date has been determined for the semester duration and scheduling for class finals.

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

-Budget has been determined by the customer.

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

-These requirements have been set by the customer.

  1. Shall be able to walk a minimum speed of 0.32 mm/sec.

-Based on the expected arena size, we have estimated an expected worst case scenario   path of 45ft during the entire game duration. The red path on the picture below indicates an expected path for our Biped to travel which totals up to 23ft. We decided to double up the expected distance traveled due to a 100% uncertainty. With a 45ft distance to travel as a worst case scenario in a duration of an hour, we have set our minimum speed requirement to be 0.32 mm/sec because 45ft*(25.4mm/inch)*(12inches/ft)/(3600secs) = 0.32 mm/sec.

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  1. Shall be able to turn up to 180 degrees on each of its sides.

-The servos that have been provided to us have a 180-degree range of motion. We can restrict this range of motion even less, but we have decided to work with this full range because we will be able to turn 180 degrees from any side, which means our robot has the capability of turning directly around no matter what foot is placed on the ground.

  1. Shall be controlled in RC mode with custom commands on the Arxterra App up to 20ft away.

We are to control the Biped in RC mode during the game as it is a requirement by the customer. Since the longest dimension of the arena is 12ft, we would operate the Biped at 12ft away in the case we were right at the edge of the arena with the mobile device on the floor.

  1. Will have a mass less than or equal to 750 grams.

We were provided the servos to our group by the customer at no cost, therefore we conducted an experiment to see how much weight the servo could handle on top of its shaft’s axis while still being able to operate properly. The reason behind this type of load test instead of the traditional motor torque test was because these servos are being placed underneath the legs of the Biped to act as ankles to help turn the Biped. It was found the servos would still be able to turn loads up to approximately 750 grams which had defined our mass limit for our Biped.

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

One of the requirements for the Biped to participate in the end-of-semester game, “Save the Human” is that the Biped must be able to detect “power-up” zones upon which the Biped can have vulnerability against the opponents. The power-up zones will be indicated by red, blue, and green color pads.

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

The Game Committee, which is the organization of Project managers for the groups participating in “Save the Human”, have decided that the game duration will possibly take up to an hour.

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

The angle climb requirement along with the maximum angle deviations have been set by the Game Committee. This requirement has been dropped from a “shall” statement to a “should” due to lack of progress with achieving walking.

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

The height climb requirement has been a traditional requirement following from previous generations of Bipeds for capability of climbing over small heights. The max height deviation of 0.5cm has been set by the game committee.

Level 2 Requirements

The Biped shall statement…

  1. Will have a DC motor that can operate effectively at 5V and produce a torque of 9.75×10^-3 ft*lbs to effectively move the Biped’s legs.

The DC Motor we are to use must be rated at 5V to operate effectively with the 5V supply from the 3Dot’s DC Motor driver. A torque of 9.75×10^-3 ft*lbs has been determined because the Biped’s legs weigh 70 grams = 0.15 lbs each, and are cranked at 1 cm = 0.0325 ft from the DC motors axis. We used the formula T=F*d to obtain the minimum torque required of our motors.

  1. Will have a servo that can operate effectively at 5V and capable of horizontally moving a mass of 68g to effectively move the Biped’s arms.

The servos that will be used to control the Biped’s arms must be able to move the combined mass of the 3D printed arms over to both the left and right side of the Biped. They must have an operating voltage of 5V or greater because they are being powered through the external power source which will be supplying 5V with the use of an LDO regulator. The servos must be capable.

  1. Will use a rotary encoder to provide data regarding the shaft position at a rate of 40xMotor Speed to help effectively keep the leg-movement system in synchronous with the arm-raising system.

The rate of the rotary encoder has been chosen to be a ratio of 40:1 with respect to the motor speed to ensure an optimum resolution of the motor shaft position during operation that way the Biped can maintain stability when walking.

  1. Shall use an RGB LED to display the color of the color pads for a minute duration when walking over the “Power-Up” zones.

An RGB LED has been chosen to be an indicator for the user to know that the color sensor has detected the color of the color pads. When the Biped picks up the color of the power-up zone color pads using the color sensor, the resulting color shall be displayed on the RGB LED for a minute duration.

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

An IMU has been chosen as our sensor or chose for detecting when the Biped is walking on inclines or declines of max angle deviations of (+/-)6.5 degrees which is the value that has been set by The Game Committee.

  1. Will use a battery capable of providing 560 mAh.

It was found that the amount of current drawn during our most energy expensive operation, walking, was 560mA. We decided to use this basis as our average current drawn from the battery. If our system must operate for a whole hour, then our battery must provide at least 560mAh because 560mA drawn for the course of an hour will have resulted in 560mAh of total energy consumed.

Conclusion

This is the final update to the requirements that will be used to come up with the verification and validation matrix. Once the matrix is completed, Biped can begin conducting tests as proof of our accomplishments.