Design Document

Video Lecture

Video, Slides

Description

The design document communicates the complete and detailed design of your project. It is substantially more detailed than the proposal and prepares you for the assembly phase of the semester. A quality design document is the key to a successful project. Use the following format.

  1. Introduction

    • Problem and Solution Overview:

      One to two paragraphs explaining the context of the problem to be solved by your project, including any relevant references to justify the existence and/or importance of the problem (i.e., the need or want for a solution). Justify the novelty of your solution or explain the expected improvements of your solution over previous results.

    • Visual Aid

      A pictorial representation of your project that puts your solution in context. Not necessarily restricted to your design. Include other external systems relevant to your project (e.g. if your solution connects to a phone via Bluetooth, draw a dotted line between your device and the phone). Note that this is not a block diagram and should explain how the solution is used, not a breakdown of inner components.

    • High-level requirements list:

      A list of three to four objective characteristics that this project must exhibit in order to solve the problem. These should be selected such that if any of these requirements were not met, the project would fail to solve the problem. Avoid vague requirements that can be interpreted a number of ways (e.g. "The radio subsystem should work reliably."). Each high-level requirement must be stated in complete sentences and displayed as a bulleted list.

  2. Design

    • Block Diagram:

      A general block diagram of the design of your solution. Each block should be as modular as possible and represent a subsystem of your design. In other words, they can be implemented independently and re-assembled later. The block diagram should be accompanied by a brief (1 paragraph) description of the high level design justifying that the design will satisfy the high-level requirements.

    • Physical Design (if applicable):

      A physical diagram of the project indicating things such as mechanical dimensions or placement of sensors and actuators. The physical diagram should also be accompanied by a brief one paragraph description.

    • [SUBSYSTEM NAME]

      For each subsystem in your block diagram, you should include a highly detailed and quantitative block description. Each description must include a statement indicating how the block contributes to the overall design dictated by the high-level requirements. Any and all design decisions must be clearly justified. Any interfaces with other blocks must be defined clearly and quantitatively.

      Include any relevant supporting figures and data in order to clearly illustrate and justify the design. Typically a well justified block design will include some or all of the following items: Circuit schematics, simulations, calculations, measurements, flow charts, mechanical diagrams (e.g. CAD drawings, only necessary for mechanical components).

      You must include a Requirements and Verifications table. Please see the R&V page for guidance on writing requirements and verification procedures.

    • Tolerance Analysis: Through discussions with your TA, identify the block or interface critical to the success of your project that poses the most challenging requirement. Analyze it mathematically and show that it can be feasibly implemented and meet its requirements. See the Tolerance Analysis guide for further guidance.
  3. Cost and Schedule

    1. Cost Analysis: Include a cost analysis of the project by following the outline below. Include a list of any non-standard parts, lab equipment, shop services, etc., which will be needed with an estimated cost for each.
      • Labor: (For each partner in the project)
        Assume a reasonable salary 
        ($/hour) x 2.5 x hours to complete = TOTAL
        Then total labor for all partners. It's a good idea to do some research into what a graduate from ECE at Illinois might typically make.
      • Parts: Include a table listing all parts (description, manufacturer, part #, quantity and cost) and quoted machine shop labor hours that will be needed to complete the project.
      • Sum of costs into a grand total
    2. Schedule:

      Include a time-table showing when each step in the expected sequence of design and construction work will be completed (general, by week), and how the tasks will be shared between the team members. (i.e. Select architecture, Design this, Design that, Buy parts, Assemble this, Assemble that, Prepare mock-up, Integrate prototype, Refine prototype, Test integrated system).

  4. Discussion of Ethics and Safety:

    1. Expand upon the ethical and safety issues raised in your proposal to ensure they are comprehensive. Add any ethical and safety concerns that arose since your proposal.
    2. Document procedures to mitigate the safety concerns of your project. For example, include a lab safety document for batteries, human/animal interfaces, aerial devices, high-power, chemicals, etc. Justify that your design decisions sufficiently protect both users and developers from unsafe conditions caused by your project.
      Projects dealing with flying vehicles, high voltage, or other high risk factors, will be required to produce a Safety Manual and demonstrate compliance with the safety manual at the time of demo.
  5. Citations:

    Any material obtained from websites, books, journal articles, or other sources not originally generated by the project team for this project must be appropriately attributed with properly cited sources. This means that even work the project team has done previously, as long as it was not done for this project, must be cited. Use IEEE format citations.

Grading

An example is available available to illustrate the expectations for a high quality Design Document: Sample DD.

Submission and Deadlines

Your design review document should be uploaded to PACE in PDF format by the deadline shown on the course calendar. If you have uploaded a DDC document to PACE, please make sure that it has been removed before uploading your Design Document.

A Micro-Tribotester to Characterize the Wear Phenomenon

Shuren Li, Boyang Shen, Sirui Wang, Ze Wang

A Micro-Tribotester to Characterize the Wear Phenomenon

Featured Project

**Problem**

Many research efforts have been made to understand the complex wear mechanisms used to reduce wear in sliding systems and thus reduce industrial losses. To characterize the wear process, coefficient of friction needs to be measured “not only after completion of the wear test but also during the wear test to understand the transitional wear behavior that led to the final state”.(Penkov) In order to improve the effectiveness and efficiency of these research methods, it is necessary to improve the instrument used to characterize the wear phenomenon to better measure the friction coefficient of the material. Although the instrument can be applied on all solid samples, we will use silicon wafer coated with SiO2 as our specimen targeted object.

**Solution Overview**

The objective of the experiment is to evaluate the wear phenomenon of the sample during the sliding test so as to obtain the wear information of the material. We will design planar positioning and force sensing system to get the move and force information of our objects. To collect the data of vertical load and horizontal friction, 2 force sensors are mounted on linear rails to minimize the radial force and ensure that only the axial forces are collected. Then, the coefficient of friction can be calculated by equation:

![](https://courses.grainger.illinois.edu/ece445zjui/pace/getfile/18615)

And to determine the relationship between the coefficient of friction and the state of wear, we use a microscope to monitor the state of wear at a given location in the wear track and evaluate the wear process during each sliding cycle. In this way, we can investigate the wear transition processes with respect to the sliding distance then transport our data to a computer. Finally, we will design our data processing method in the computer to successfully obtain an acceptable result in the margin error.

**Solution Components**

1. Motion Platform: This subsystem includes a linear actuator that moves the sample in reciprocating motion along X-axis, a stationary counter surface that applies constant vertical load onto the sample, and another actuator that compresses the spring and provides a vertical load to the counter sample.

2. Specimen and Counter surface: We will test the wear and friction between the specimen and the counter surface during the sliding test. A 10 × 10 mm^2 silicon (Si) wafer coated with 50 nm thick SiO2 will be used as the specimen and a stainless-steel ball with a diameter of 1 mm was used as the counter surface.

3. Sensors: This subsystem includes two force sensors that measure the vertical load and horizontal friction. The Load Sensor should assemble along with the Z-axis actuator. To measure the friction without the effect of load, we assemble the Load Sensor and Friction Sensor sensor on the Linear Rails, as the photo attached shows. Since the sensors are strain gauges and only outputs, small changes in resistance, amplifiers, and ADC are needed to collect the signal and send converted data to the computer.

4. Data Processing: This subsystem includes acquiring raw data of load and friction on the computer, applying necessary filters to reduce noise and improve accuracy, and plotting the result that reflects the relationship between the sliding cycles and coefficient of friction for our sample.

![](https://courses.grainger.illinois.edu/ece445zjui/pace/getfile/18611)

**Criterion for Success**

1. Motion platform can perform precise reciprocation. The control system can effectively control the number and speed of reciprocating motion.

2. The acquisition unit can collect data effectively and can transfer the data that can be processed to the computer.

3. On a computer, the raw data can be processed into a readable graph based on algorithms set up. By analyzing the graph, the relationship between the data and the expected results can be correctly obtained.

**References**

Penkov OV, Khadem M, Nieto A, Kim T-H, Kim D-E. Design and Construction of a Micro-Tribotester for Precise In-Situ Wear Measurements. Micromachines. 2017; 8(4):103. https://doi.org/10.3390/mi8040103