Computer-Controlled Electronic Brake Release System for Drag
Transcription
Computer-Controlled Electronic Brake Release System for Drag
Computer-Controlled Electronic Brake Release System for Drag Racing Vehicles May 8, 2006 Team #3 Manuel Trejo Jr. Robert Payne Art Trevino Craig Davis An electronically controlled brake release system activated by a green light optical sensor. Overview Problem Statement Design Phase Approach Literature and Patent Research Market Analysis Design Constraints and User Requirements Engineering Codes and Standards Design Concepts Product Specifications High Level Block Diagram Major Components Detailed Design Implementation and Integration Major Problems Comments and Conclusion Problem Statement Start time delay and early start are two critical concerns that can be overcome by implementing an automatic brake release system which is activated upon receiving the green light “go” signal. Design Phase Approach Phase 0: Planning and research Patent research Standards and regulations research Requirements and constraints development Market analysis Phase I: Detailed design Optical sensor development Develop algorithm Complete circuit schematic using PSpice Build prototype Test for functionality and modify design if necessary Layout using OrCAD Develop PCB Populate PCB Test for functionality and modify if necessary IR sensor/ RPM counter development Same process as optical sensor Design Phase Approach Continued Develop micro-controller operation Develop algorithms and source code to: Count RPM Calculate speed Calculate distance traveled Calculate distance remaining Communicate with brake system Communicate with engine cutoff trigger Display data on LCD’s Phase II: Prototype development Install components and connect to micro-controller Test for functionality Debug code Perform final system modifications Final test Assemble documentation package Total project time: 179 days Literature and Patent Research No Computer-Controlled Electronic Brake Release System Exists Similar Concepts Have Been Developed Transmission brake release apparatus Market Analysis $1.7 billion annually* Patent protection and competition Market domination *Performance Racing Industry Magazine, 2001 Market Demographics Global Design Constraints Engineering Standards ANSI, IEEE, ASME Environment Future PCB (printed circuit board) will meet ROHS compliance Sustainability Long-term sales: product reliability will reduce the number of units needed Plan to offset the reduction from new GUI product version upgrade Ethical National Hot Rod Association (NHRA) rules, no ethical issues exist currently Safety and Health Standards OSHA: no health or safety issues Society No effect on society: used by race car drivers only Political No political issues from the product Liability Manual disabling could cause malfunctions with minimal liability No infringements on similar ideas or patents Local Design Constraints Cost Definite constraint until sales start offset cost Scheduling Efficiency through good management of supplies, transportation and weather Manufacturability Local constraint due to anticipated volume Engineering Codes and Standards Complied with local government regulations Ethical No ethical issues on local front Legal No infringement on similar ideas or patents, covered previously by other members during a patent research User Requirements System shall not alter vehicle performance Optical sensor shall be able to receive a green light signal from 10-20 feet away System shall be compact an unobtrusive System shall be weather proof System shall be shock proof System shall have an override feature System shall operate from 12VDC source System shall be easy to operate Engineering Codes and Standards IEC Std 61131-2 IEC Programmable ControllersEquipment Requirements and Tests IEEE Std C82.38-1994 IEEE Guide on Electrostatic Discharge IEEE Std 1100-1999 IEEE Recommended Practice for Powering and Grounding Electronic Equipment IEEE Std 518-1982 Guide for Minimizing External Electrical Noise Inputs to Controllers OSHA Std 1910 OSHA Standard for Electrical Equipment Design Concepts Concept #1: Gas powered go-cart Concept #2: Electric motor with wheel and axle Concept #3: Ford Mustang Design Concept #1 This design concept required the product to be implemented on a go-cart. A 24V electromagnetic brake would serve as the primary braking mechanism. The vehicle would require rear-axle modifications to fit the electromagnetic brake assembly as well as the RPM encoder. Design Concept #2 This design concept is the simplest of the three. It requires an electric motor with a small wheel axle to simulate the braking mechanism. The electronic circuit will drive the electric motor when the green light is activated. The only specific requirement or modification is for the microcontroller to deliver enough power to drive the motor. Design Concept #3 This final design concept best incorporates the final product as it would be used in competition. The system will be implemented on a Ford Mustang with an automatic transmission brake system. Pugh Matrix Product Specifications 12V DC Battery Operated Maximum 15’ range for optical sensor Directional up to 15 degrees of field of view 5V Digital Logic I/O Signals User friendly hardware interface System Arm/Reset capability Manual override Multiple microcontroller I/O ports RS232 connectivity BASIC programming language Quick-disconnect electrical connections Temperature resistant High Level Block Diagram Flow Chart Major Components Control Panel Easy-to-use user interface Features ON/OFF, ARM/RESET, override switches, status indicator LEDs, LCD, and speed control Electric Motor & Encoder Power antenna motor used to simulate transmission brake release interface Crank shaft angle sensor used for I/R encoder assembly Microcontroller Manage all incoming and outgoing signals Receives green light signal, outputs 5V signal to relay OOPIC-R microcontroller used due to availability, cost, popularity and interfacing Initially the MSP-430 was eliminated because of high cost and complexity Detailed Design (Hardware) Amplifier/Comparator Circuit Cont. Voltage Output for Sunny Conditions Voltage Output For Overcast Conditions 800 700 y = 1.2137x + 118 700 716 720 685 690 y = 1.19231x + 300 600 568 600 595 564 560 606 580 598 575 592 606 582 546 528 Ouput Voltage (mV) Voltage Output (mV) y = 1.1593x + 115 500 400 370 350 340 380 355 370 352 333 300 243 235 241 231 200 118 496 468 449 458 435 424 400 393 373 300 333 313 319 298 300 284 536 549 610 600 590 580 570 560 519 504 465 y = 1.13846x + 284 398 358 338 200 Green Light Vout (mV) Yellow Light Vout (mV) Green Light Vout (mV) 115 100 500 512 491 581 100 Yellow Light Vout (mV) 0 100 195 195 295 298 300 400 482 484 490 495 500 590 0 596 250 264 276 296 320 357 385 Base Voltage (mV) 396 412 426 438 453 468 471 480 500 Base Voltage (mV) Voltage Output (mV) for Indoor Lighting Conditions Output Voltages Under Low Light Conditions 700 y = 1.20455x + 496 700 y = 1.16783x + 476 510 476 431 400 524 451 528 453 526 456 545 569 569 579 579 582 588 487 497 496 508 512 486 544 516 465 600 458 466 514 605 528 610 530 631 545 628 545 639 643 562 567 406 300 Green Light Vout Yellow Light Vout 612 496 447 508 519 456 565 526 490 466 552 501 510 537 523 546 50 0 49 0 47 2 46 4 45 0 43 9 42 7 41 1 40 6 39 9 572 581 595 y = 1.12121x + 447 400 300 200 Green Light Vout Yellow Light Vout Linear (Yellow Light Vout) Linear (Green Light Vout) 100 Base Voltage (mV) 560 655 623 475 100 0 618 582 546 500 y = 1.12587x + 406 200 600 Voltage Output (mV) 500 35 7 Output Voltage (mV) 600 642 600 0 393 404 411 425 433 440 451 461 473 Baseline Volatge (mV) 480 492 500 512 525 510 Detailed Design (Software) OOPic R uses object oriented programming Develop basic programs BASIC chosen for simplicity of use Virtual circuit created for solenoid output Subroutines for time delay, timer and LCD readout Integration and Implementation Hardware Hardware Input Output Δt Delay observed at local IHRA event Tested system delay Successful results Tested with 1Hz/5V input square wave signal 4.8 ms delay measured from input to output Major Problems Software Running nested loops resulted in longer running time of code execution Displaying multiple sets of information on the display Delaying the brake for 10 seconds without delaying the code Using the real time clock string data as integers Parsing the data from the code Truncation of numbers Hardware LDR’s susceptibility to heat damage IC adaptor mounts installed in reverse Design flaw in placement of power switch Insufficient current to activate the relay Comments and Conclusion Improve optical sensor with more complex optical lens array Increase field of view Increase sensitivity Automatic ambient light detection Use digital image processing for optical sensors Use multiple microprocessors to handle various tasks simultaneously Re-design for efficiency and performance Design for hands-free user interfacing (i.e., voice commands) Summary Problem Statement Design Phase Approach Literature and Patent Research Market Analysis Design Constraints and User Requirements Engineering Codes and Standards Design Concepts Product Specifications High Level Block Diagram Major Components Detailed Design Implementation and Integration Major Problems Comments and Conclusion Visit our website! https://lonestar.utsa.edu/manuelt/index.htm