P16221 – FSAE Shock Dynamometer Preliminary Detailed Design Review November 13, 2015

Aung Toe – EE Jim Holmes – EE – Project Manager Sal Fava – ME – Chief Engineer Chris Batorski – ME – Facilitator Andrew Dodd – ISE P16221 – MSD Team

Address concerns from System Level DR System Level Design Flowchart Updates Engineering Spec Updates Current Bill of Materials Safety Considerations User Interface (software) Model Overview Mechanical Systems Analysis Electrical Schematics Risk Management Project Plan Team Efficiency Agenda

Concerned about quantity of data transferred – Put two micros in: one for sensor read and one for dyno control – Sample only important sections of track data Add internal frames to the energy chart that shows the internal resistances to energy transfers Verify that the load cell will not measure its own internal deflection, just the force applied to it – Verified by spec sheet Track the severity chart sum over time to show progress – Chart created and updated weekly (owned by Jim) Resolved Issues From Previous Review

Keep verification testing in mind during the design process to make testing easier at the end – Developing test plans now Customer movement metric needs to be better defined – Complete. See engineering specs Due to the dynamic nature of the dyno, a timing diagram should be created – Timing Diagram Timing Diagram Need a reasonable life expectancy of the dyno and write a spec on it – See engineering specs for life cycle and maintenance interval Resolved Issues From Previous Review (Cont.)

What will keep the dyno from “walking across the floor” while it is running? – Open issue. Will need to perform isolation analysis from dyno to floor Develop an Engineering Analysis vs. Risk vs. Verification Test metric to make sure everything is covered. – Still in progress Any function in the system functional block diagram with only one child should be combined into one block – Low priority, still in progress Open Issues From Last Review

Engineering Requirements

BOM

Predicted Costs

System Level Design Flowchart

Goals of sub-system: – Protect user from serious damper failure – Not impede user activities within working zone – Low cost Important features – Enclosure – Emergency Stop Switch – Safety Door Lock – Safety Circuit Subsystem Design Safety

Major Components Aluminum Extrusion Frame – Minitec 45x45 F Plastic Shielding – Polycarbonate sheeting Door Safety Latch Safety Circuit Interfaces Test stand base – Bolted to base Work Area – Surrounds the masts and test area Emergency Stop Switch – Will be mounted to the frame Safety Sub-System Overview

Goals of Subsystem – Provide user with a way to control and program the test stand – Post processes the raw data and saves it in.csv format Important Features – Car Parameter Inputs – Track Data/Profile Selection – Post Processing – Graph Display Subsystem Design Software Interface

Software Interface Proposed Input Display

EquationsVariables K w = Wheel Rate K s = Spring Rate MR = Motion Ratio ω s/us = Natural Frequency (sprung/unsprung mass) m s/us = Mass (sprung/unsprung) c crs/us = Critical Damping (sprung/unsprung mass) Software Interface Calculations

Software Interface Results (Characterization)

Software Interface Results (Track Data)

Large components placed in the model Safety enclosure not shown Model Overview

Overview of some simple design practices Mechanical Design

Forced on arm at Given locations Determine if there are any points of concern Motion Ratio Arm

Determine the min diameter shoulder bolts that can be used in each location Shoulder Bolt Sizing

Buckling Calculation Hand Calculations Mast Sizing

Crossbar Clamping Calculation

Electrical System Schematic

Proof of Concept: Controller

Safety Circuit Loop Force sensor/ Potentiometer resolution test IR sensor safety circuit test UART and PC interface test Proof of Concept: Testing to be done

IR sensor test Proof of Concept: Testing so far

Serial Speed Analysis – Inputs Memory Requirements (64 bits of data in 0.002s) – Output 32,000 bits/s – Conclusion- feasible baud rates: 38,400 56, Theoretical Models: Serial Interface (UART)

Theoretical Models: Data Flow

Risk Assessment

Updated Project Plan

Atmel Temperature Sensor Test: Initially took 3 days; could repeat in an hour. Efficiency (3%) 3-D Model: Initially took 2 team members about 6 hours a piece; probably could repeat in about half of the time. Efficiency (50%) – Note: Still in progress Source Ball screw that will meet our needs: Initially took a few weeks; could repeat in an hour. Efficiency (1%) Team Efficiency

Questions?