AT-ST Mass Report

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By: Joseph Cho (Mission, Systems, and Testing)

Verified By: Intiser Kabir (Project Manager)

Approved By: Miguel Garcia (Quality Assurance)

Table of Contents

Introduction

This blog post will show the mass of the AT-ST and include the ways that the masses have been initially estimated. All of the parts have been measured for the final mass report.

Mass resource report

Figure 1: Mass Report

Description:

Mass of the AT-ST has been estimated by the given masses on the retailers. The 3D printed parts were estimated by rough calculation shown below. PCB mass was estimated by comparing the size to the 3DoT board size.

All of the parts have been measured on the AT-ST. The total mass came out to be 256.80 grams. There are some parts that have been listed as 0 grams because they have been put together in the body weight.

Measuring the Mass

Figure 2: Scale used to measure the mass

Description:

Ozeri pronto digital scale was used to measure the mass of our components. The scale had to be placed on a leveled surface and calibrated by pressing “TARE” button. The weight of the parts was rounded to the nearest gram. I would recommend a scale that has more accuracy for lower masses.

Theo Jansen Leg Dimensions

Figure 3: Theo Jansen leg concept

Description

With the Theo Jansen leg dimensions, we are going to estimate the volume of each legs to find the mass of the legs. The Theo Jansen legs will have a width of 3.96875 mm and thickness of 3.825mm.

Theo Jansen Leg 3D mechanical drawings (from mechanical drawing blog post)

Figure 4: Theo Jansen Leg 3D mechanical drawing

Body (housing for 3DoT and PCB)

Figure 5: Estimated Body Volume

Calculations

Figure 7: Mass Calculations for supports and Joints

Figure 8: Total Mass for one Leg and Joints

Figure 9: Total Mass Calculation for body (box)

Description:

The legs and body calculations were done by estimating the volume of the 3D printed parts and multiplying their density to them. Since 3D prints do not fill the parts completely with the material, the estimate of the mass will be higher than the actual weight. The mass of the AT-ST 3D printed parts will be around 253 grams for the box and 120 grams for the legs.

Resources

  1. http://www.strandbeest.com/beests_leg.php
  2. http://www.psyclops.com/tools/technotes/materials/density.html
  3. https://docs.google.com/spreadsheets/d/1l4bPs0FaRDSLj46PryDBNb4UZcGDcVGFgoV37JaNrXk/edit?usp=sharing

Goliath Spring 2018 – Mechanical Drawings

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By: Daniel Guerrero (M&D Engineer)

Verified By: Ernie Trujillo (Project Manager)

Approved By: Miguel Garcia (Quality Assurance)

Figure 1 – Preliminary sketches for the Goliath Tank.

The reason behind this design was to follow the concept of the spring 2016’s design, to create a box shell of the tank as a preliminary design and attempt to fit all of the equipment inside. I tried to steer away from just a simple box for this design and tried to follow the general shape of the German 302 goliath tank. As for the placement of all the gaps in this design, I was aiming to have it accessible enough to configure all of our equipment into the design. For this first edition, I kept the size to five inches in length by four inches in width and about three inches in height.

 

Goliath Spring 2018 – Interface Matrix

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By: Ryan Nguyen (MST Engineer)

Verified By: Ernie Trujillo (Project Manager)

Approved By: Miguel Garcia (Quality Assurance)

The interface matrix shows how each subsystem of Goliath connects to the ATmega32U4 microcontroller. The top header consists of the sub-systems, the left column has the name and pin number of the ATmega32U4. The matrix maps out how each pin is connected.

 

From the ATmega32U4, the version 6x 3 dot board specifies 16 pins that students can use for their robots. The first matrix shows the two PCBS of Goliath that will be connected to the three dot board, the top header shield, and the front sensor shield.

Figure 1 – Interface matrix of ATmega32U4

The second matrix shows how the components of the sensor shield will be connected; Goliath uses two UV sensors, as well as a range finder to navigate the maze.

Figure 2 – Interface matrix of front sensor shield

Lastly, Goliath uses a gyrometer, connected to the top PCB, to determine turning in the maze.

Figure 3 – Interface matrix of top header shield

Goliath Spring 2018 – Fritzing Diagram

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Written by Milton Ramirez (E&C Engineer)

Verified by Ernie Trujillo (Project Manager)

Approved by Miguel Garcia (Quality Assurance)

Figure 1 – Fritzing Diagram for the Goliath Tank.

Parts

  • Pro Micro
  • Motor driver
  • Gyro
  • Range-finder  
  • Multiplexer
  • Bluetooth
  • Color sensor
  • Battery

 

Description

This a prototype of how we will connect the parts we are going to use, but some of these parts might not make the final design. In this prototype, our processor will be the pro-micro instead of the 3Dot board, since Professor Hill is still working on the 3dot board. Also, for that same reason, we will have to use a Bluetooth circuit for our prototype since the 3dot has Bluetooth implemented in it. We will probably have to use this configuration for most of our testing since we won’t get the 3dot until later in the semester. Also, we have a motor driver to control our motors. We are also using a multiplexer for our sensor, which is a Gyro sensor and a color sensor. Then we also have a range-finder, which this and the color sensor are floating outside on purpose, because the color sensor goes in the bottom of the Goliath. The range-finder will be somewhere in the front. Also, the specific part number is not included since that will also change for the last design.

References

  1. http://fritzing.org/home/
  2. https://www.sparkfun.com/products/12587

 

 

Goliath Spring 2018 – Planning and Scheduling

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By: Ernie Trujillo (Project Manager)

Approved By: Miguel Garcia (Quality Assurance)

Table of Contents

Introduction

To achieve mission success for the Goliath Tank, a Gantt Chart was created by the Project Manager; the chart depicts all the pertinent tasks that need to be completed before attempting the mission through the maze. With the Gantt Chart, the Project Manager was able to take the tasks from the Task Matrix and display it in a visual chart that depicts the amount of time that is allotted per task and during what time of the semester this task will be worked on.

Figure 1 – Gantt Chart (1/3), these tasks mainly focus on being prepared for the Preliminary Design Review

 

Figure 2 – Gantt Chart (2/3), tasks that are pertinent to implementing the hardware to the Goliath.

 

Figure 3 – Gantt Chart (3/3), tasks that focus on software implementation and final verification of the Goliath.

Broad Layout of Project Schedule

Phase 1 (Research), Weeks 1-5:

  • Look through blog posts from prior semesters on Arxterra website for useful information that the current team can implement.
  • Begin developing level 1 & 2 requirements to meet mission objectives and customer expectations.
  • Begin layout for all tasks required to reach mission success at the end of the 16th

Phase 2 (Preliminary Design Review), Weeks 6 – 8:

  • Achieve a thorough schedule to lay out all tasks required to be complete by the team to bring the project to fruition.
  • Accomplish preliminary tasks: preliminary 3D model, system block diagram, Fritzing diagram, mechanical drawings, resource reports, work and product breakdown structure.

Phase 3 (Rapid Prototyping), Weeks 9 – 12:

  • Design multiple iterations of Goliath Tank to make the final product more efficient.
  • Create a program that will integrate all systems that are in the system block diagram. Also, ensure that the program will have the robot operate in a manner that meets mission objectives.
  • Have E & C Engineer work on creating and finalizing custom PCB.
  • Have MST Engineer work on Arxterra custom command and telemetry (Application side)

Phase 4 (Final Product & Mission Success), Weeks 13 – 16:

  • Finalize Goliath Tank 3D model and ensure that all systems are working properly.
  • Complete Project Video that shows the progression of project and implementation of the Engineering Method.
  • Complete Final Blog Post which displays a comprehensive overview of the Goliath project from start to finish.
  • On the day of the Final, demonstrate that the Goliath can navigate through the maze and meet all the L1 & 2 requirements.

References

  1. https://www.projectlibre.com/
  2. Task Matrix

Goliath Spring 2018 – System Block Diagram

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By: Ryan Nguyen (MST Engineer)

Verified By: Ernie Trujillo (Project Manager)

Approved By: Miguel Garcia (Quality Assurance)

System Block Diagram

Figure 1 – System Block Diagram for the Goliath Tank.

The system block diagram illustrates how components of the Goliath communicate and connect with each other; from the control panel that uses Wi-Fi to talk with the mobile app to the wheels and treads. More detailed specific components such as the HM11 Bluetooth model is added, and various parts on the PCB parts are laid out; more items are expected when the E&C engineer completes trade-off studies. The 3DoT board houses a rechargeable battery that powers the motor driver and the Atmega32U4, which in turn powers the PCB. The number of pins is listed to demonstrate a rough idea of how many pins are required and create a rough layout for the interface matrix.

Goliath Spring 2018 – Preliminary Budget

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By: Ernie Trujillo (Project Manager)

Approved By: Miguel Garcia (Quality Assurance)

Introduction

The customer allotted $200 towards the Goliath Tank project. At this moment, the total expenditure of the project cannot be confirmed as the cost for the PCB and the 3D prints designs are unknown. Also, since the definitions of the maze are not complete at this moment, there is a chance that some sensors will be added to the list while others are removed. About 60% of the budget has been established while the remaining funds will be used for the last few parts that will be needed to complete the Goliath Tank.

Figure 1 – Excel spreadsheet for the components needed for the project.

The spreadsheet provides most of the parts that will be required for mission success. (Will be updated to include all the parts) Included is useful information to the team such as the quantity, cost, and link to the part.

Figure 2 – Totals and general overview of the project budget.

Sources:

  1. https://docs.google.com/spreadsheets/d/1X2e8fMk9zH4d6ugtWx0KzsvcbpDvAjY_uL_h4tcDotE/edit?usp=sharing

 

 

AT-ST Verification Test Plan

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By: Joseph Cho (Mission, Systems, and Testing)

Verified By: Intiser Kabir (Project Manager)

Approved By: Miguel Garcia (Quality Assurance)

Table of Contents

Introduction

Verification test plan is used to verify our L1 and L2 requirements through analysis, inspection, demonstration, and/or testing. The L1 and L2 requirements are listed in the spreadsheet below. The test plans will be generated from the spreadsheet. Few of L1 and L2 requirements have been reworded by MST.

Please be noted:

GL1 is General Level 1 requirement;

SL1 is Specific Level 1 requirement;

SL2 is Specific Level 2 requirement.

Verification Matrix

Figure 2: Verification Matrix continued.

Figure 3: Verification Matrix continued.Description:

This matrix contains all of the verification needed for the AT-ST. Each test cases are differently colored. Test Case 1 is green, Test Case 2 is blue, Test Case 3 is yellow, and Test Case 4 is red.

 

Test Cases

TC-01: General Inspection

Description: Verify all of AT-ST inspections..

Test Environment: Indoors on a level surface. Preferred to be inside ECS 316.

Figure 4: Test Case 1 (included in the Verification matrix)

Figure 5: Test Case 1 Continued

Figure 6: Test Case 1 Continued

Figure 7: Test Case 1 Procedure Step

TC-02: Maze Demonstration

Description: Verify all requirements for the hedge maze.

Test Environment: Indoors on a level surface. Preferred to be inside ECS 316.

 

Figure 8: Test Case 2

Figure 9: Test Case 2 Continued

Figure 10: Test Case 2 Procedure Step

TC-03: ArxTerra App. Demonstration

Description: Verify all requirements for ArxTerra App. Demonstration

Test Environment: Indoors on a level surface. Preferred to be inside ECS 316.

Figure 11: Test Case 3

Figure 12: Test Case 3 Procedure Step

TC-04: Mechanical Testing

Description: Test all mechanical requirements of AT-ST

Test Environment: Indoors on a level surface. Preferred to be inside ECS 316.

Figure 13: Test Case 4

Figure 14: Test Case 4 Procedure Step

Description

The test cases above is a list of test cases that will be done in order to test the level one and level two requirements of AT-ST. All these tests will be done as the project progresses and additional test cases may be added in the near future.

References

Goliath Fall 2017 Verification and validation test plans:

https://docs.google.com/document/d/1AxqEOK9IbOjYYHCB_hjBvkPCMkmBkUHTAropGCucphM/edit?usp=sharing

Goliath Verification and validation matrix:

https://docs.google.com/spreadsheets/d/1nidxLcOYEpPlr_o6vkksaHdT84JXj-LlkuektFs7Hwg/edit?usp=sharing

AT-ST Verification and validation matrix:

https://docs.google.com/spreadsheets/d/1HHaQliwvLYbqErqJi2AVOlqGEzNX7grKOYJ2CBUFQ7M/edit?usp=sharing

AT-ST L1 and L2 requirements:

www.arxterra.com/spring-2018-at-st-project-specific-requirements-and-objective-l1l2/

 

Spring 2018: BiPed Work Breakdown Structure

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By: Miguel Gonzalez (Project Manager & Manufacturing)

Approved by: Miguel Garcia (Quality Assurance)

Table of Contents

Work Breakdown Structure

For project BiPed, the group consisted of three members fulfilling the roles of Project Manager, E&C, MST, and Manufacturing Engineer. Since the group consisted of fewer members than the positions to fill the manufacturing role of the team was given to the Project Manager.

The diagram below shows the workload of the project and how it is distributed among the team. It is based on the job descriptions and shows major tasks that each person is responsible for. We will be taking a look at each team members role more closely to better understand the structure of the team and its workload.

Fig.1 BiPed Work Breakdown Structure

Miguel Gonzalez (Project Manager)

Fig.2 PM and Manufacturing Engineer Tasks (Blue)

At the top of the WBS in blue, we have the project manager section. Note that in our case the project manager is also the manufacturing engineer and thus the tasks for both roles are given to the same person. The second blue icon shows the tasks specific to the project manager which has the project manager responsible for the following tasks:

  • Creating and managing schedule
  • Creating a budget list
  • Creating the preliminary report
  • Creating the final blog post
  • Creating project video
  • Define Work Breakdown Schedule

The manufacturing tasks given to the project manager are listed to the right side of the WBS also in blue. These tasks are broken down into three sections Mechanical Design, 3D Modeling, and Assembly. These sections were created based on which tasks are needed to be done before moving on to the next section. For example, Mechanical Design is a prerequisite for 3D Modeling and Assemble thus it is located on top of the other tasks.

Jeffery De La Cruz (MST)

Fig.3 MST Tasks (Red)

Moving on to the left side of the WBS (in red), we have all the tasks assigned to the MST engineer. Once again, these tasks are divided up into three sections System Designs, Software, and System Tests. The system designs include tasks that have a focus on research and trade studies that will end up helping with the software development and system test. Once those tasks are done the MST engineer can proceed with implementing the software with the Arxterra control panel and onto an android application. The final tasks for the MST engineer focus on verifying and testing all sections of the robot to see if they are operational.

Jorge Hernandez (E&C)

Fig.4 E&C Tasks (Green)

The final branch in the WBS applies to the E&C engineer and his tasks needed for a successful project. The E&C has the greatest responsibility for the success of the robot becoming operational. His roles are divided into 4 categories Electronics Design, Experiments, Microcontroller, and Control. These categories cover a wide range of taks that need to be realized to proceed with the overall goal of the Biped project which is stated in our preliminary design blog post and here.

Spring 2018: Biped Fabrication Methods (Trade-off Study)

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By: Miguel Gonzalez (Project Manager & Manufacturing)

Approved by: Miguel Garcia (Quality Assurance)

Table of Contents

Related Requirements

L1-3: Micro FOBO will have 2 legs.

L1-4: Micro FOBO will be a toy robot based on the design of the FOBO by Jonathan Dowdall.

L1-18: Micro FOBO shall be able to traverse cloth, paper, and linoleum materials.

Introduction

When thinking about manufacturing our robot we looked at the many fabrication methods available that we could use to create the BiPed. Of course, the list of ways we can manufacture our robot can be endless, but we made sure to focus our research to limit this list. Our goal for this study is to list the most feasible methods of fabricating our robot and compare the pros and cons of each method. The top three most feasible fabrication methods we could implement on our robot was sheet metal folding, laser cutting, and 3D printing. This blog study will look at each method mentioned to see the benefits and disadvantages of incorporating them into our design. Below you can find our study and the results we arrived when conducting a few tests.

Sheet Metal Folding Method

Fig.1 Sheet metal folding example

The first fabrication method we looked at was sheet metal folding which is a process of getting thin metal sheets and cutting them into specific shapes that would be folded to produce a three-dimensional shape. This shape can be a servo mount, 3DoT casing, robot feet, and so much more. Sheet metal folding is cheap and is a good way to produce sturdy parts rapidly without much effort. One of the drawbacks of this method is that complicated designs are almost impossible to produce. Accurately measured pieces are hard to produce and making exact copies of parts that share the exact dimensions are nearly impossible to make using this method. These drawbacks are too big to ignore especially when we plan on creating a robot that requires precision measurements and complicated design.

Laser Cutting Wood

Fig.2 Laser cutting example

The next fabrication method we consider was laser cutting. Laser cutting is a very niche fabrication method for hobbyists but has been gaining traction in the recent years. With the laser cutting method, you can use various materials for your builds such as sheet metal, plastics, and even wood. This method of fabrication utilizes the precision of a powerful laser to cut material into a predefined shape. This means that you can achieve very accurate and precise cuts. Laser cutting, in general, is very versatile but our team realized that we lacked knowledge on how to use a laser cutter. It was also clear that laser cutting would only be used for a section of our robot design and can’t make complicated three-dimensional shapes that extend well above the laser’s cutting threshold. This takes us to the third fabrication method mentioned below.

3D Printing

Fig.3 3D Printing Diagram

Out of all the fabrication methods described in this blog post, 3D Printing was the only method of creating stuff that has been used by a team member. 3D Printing is a fabrication process of creating a three-dimensional object by adding small amounts of material upon itself until the desired shape/object is obtained. There are multiple ways a 3D printer can produce a design, but we focused on an additive manufacturing process called Fused Filament Fabrication (FFF). This is the most common consumer grade process that is readily available.

With 3D printing, we can model our robot’s chassis designs and print them out at the same dimensions specified in the CAD model. This would allow us to expedite the design and manufacturing process in our project. 3D printing also allows us to create precise measurements and make exact copies of parts while maintaining constant measurement accuracy at each copy. With FFF 3D printing we are limited to using only plastic materials but fortunately, we can choose from various plastics that have different properties. In a later blog post, we will be looking at the different materials available for FFF 3D printing and looking at their properties.

Conclusion

After considering all three methods of fabrication we decided that we should use 3D printing to create all the designs in our robot. 3D printing’s only drawback was that it can only produce stuff in plastics, but our team has concluded that plastic has enough robustness to make our robot function and complete the maze. Lastly, our class has been informed that multiple 3D printers are available in house to produce our robot parts and thus this method of fabrication is also the most available for us.

Sources

  1. https://www.tractorsupply.com/know-how_hardware-tools_metalworking_working-with-sheet-metal-safety-tools-and-sheetmetal-projects
  2. https://www.wikihow.com/Use-a-Laser-Cutter
  3. https://library.ucalgary.ca/makerspace_equipment/3D_printing
  4. https://www.3diy.org/