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Capstone Design Project: MOUNTAIN BIKE ANTI-LOCK BRAKE SYSTEM

College of Engineering and Applied Science. Capstone Design Project: MOUNTAIN BIKE ANTI-LOCK BRAKE SYSTEM. Electrical Engineering 595 Spring Semester 2004 Design Group #3. Design Group #3 Team Members. Mark Adamak BSEE and BSME Presentation Mgr Ph: (262) 548-0331 madamak@uwm.edu.

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Capstone Design Project: MOUNTAIN BIKE ANTI-LOCK BRAKE SYSTEM

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  1. College of Engineering and Applied Science Capstone Design Project: MOUNTAIN BIKE ANTI-LOCK BRAKE SYSTEM Electrical Engineering 595 Spring Semester 2004 Design Group #3

  2. Design Group #3 Team Members Mark Adamak BSEE and BSME Presentation Mgr Ph: (262) 548-0331 madamak@uwm.edu Nick Bertrand BSEE Project Archiver Ph: (414) 727-4912 bertran2@uwm.edu Eric Graves BSEE and CS minor Fearless Leader Ph: (414)232-0792; ejgraves@uwm.edu

  3. Design Group #3 Team Members (Cont.) David Mapes BSEE General Work/Researcher Ph: (414) 324-5816 dmapes@uwm.edu Richard Roh BSEE and BioChem Report Manager Ph: (262) 853-1475; rcroh@wi.rr.com

  4. Anti-Lock Brake System • A skidding wheel has less traction than a non-skidding wheel. • An anti-lock breaking system (ABS) is a means to prevent a vehicle from locking up its wheels and skidding out of control. • By keeping the wheels from skidding while you slow down, anti-lock brakes benefit you in two ways: You'll stop faster, and you'll be able to steer while you stop. • ABS works by sensing if the wheel has stopped rotating while the brakes are applied. If this happens the controller takes over the application of brake pressure in a rapid pulsating fashion.

  5. The Mountain Bike ABS Control System Description • Antilock brake system for a dual rotor, hydraulic disc brake assembly • The ABS system will take actions to avoid the locking of brakes during rapid deceleration and low friction conditions • Enables steering control in an aggressive braking situation • Rider will have the ability to manually over-ride the ABS action • Small display will inform the rider of the status of the system

  6. Product Level Standard Requirements Market • Estimated Annual Volume: 5000 units • Estimated Market Size: 100 % • Minimum List Price: $250.00 • Maximum Product Cost: $150.00 • Maximum Prototype Cost: $500.00 • Market Demography: 18-32 male and female • Market Competitors: Avid, Shamano • Market Industry: Competition/Recreational sports equipment

  7. Product Level Standard Requirements Power • 12V DC sealed cell lead acid battery • Output Voltage Range: 10-14 VDC • Instantaneous Maximum Available Power: 50 Watts • Charge Capacity: 4.0 A-hr • 12V battery charger • Input Voltage Range: 115-125 VAC • Output Voltage To Battery: 14 VDC • Output Current To Battery: 0.5 A • Output Power: 15 Watts

  8. Product Level Standard Requirements Mechanical • Maximum Product Volume: 0.1 cubic meters • Maximum Product Mass: 5.0 kg • Number of Printed Circuit Boards: 4 • Total Printed Circuit Board Area: 400 square centimeters • Impact Shock Force: 4 G’s • Moisture Resistance: Weather Resistant • Maximum Total Part Count: 250 • Unique Parts: 200

  9. Product Level Standard Requirements Environmental • Operating Temperature Range: 12 – 49 C • Operating Humidity Range: 0 – 100% • Storage Temperature Range: 0 – 50 C • Storage Humidity Range: 0 – 80% • Storage Duration: 2 years • Charging Battery Temperature Range: 0 – 60 C

  10. Product Level Standard Requirements Life Cycle • Estimated Product Lifetime: 5 years • Service Strategy: Factory Repair • Product Life MTBF: 2 years • Full Warranty Period: 90 days • Product Disposal: Recycle

  11. Product Level Performance Requirements Product Goal • Improved Braking Ability • Increase stopping performance by decreasing the straight line stopping distance of an average sized rider (140-200 lbs) by 10% or more • Internal Design Tolerances • Max braking fluid pressure of 800 psi • Nominal braking fluid pressure of 500 psi

  12. Product Level Performance Requirements User Control • Power switch • User turns power onto the unit when use is desired • ABS Override • User has control over ABS action on both front and rear wheels, user can disable ABS action if it is desired that either wheels lock • Display informs rider of • Applied Power • Battery Charge • ABS Activity

  13. Product Level Performance Requirements System Monitoring • Wheel Rotation • System monitors wheel rotation to determine whether they are locked • Brake Activity • System monitors whether the brakes are being applied or not

  14. Block Ownership Key Power Supply Eric Graves Richard Roh Block Connection Key David Mapes 120 VAC Nick Bertrand +12 VDC Mark Adamak +5 VDC System Sensors/ LCD Microcontroller Note: Colored outline represents person who will assist primary owner of block Data ABS Actuator User Control And Feed Back

  15. Block Ownership Key Power Supply Eric Graves Richard Roh Block Connection Key David Mapes 120 VAC Nick Bertrand +12 VDC Mark Adamak +5 VDC System Sensors/ LCD Microcontroller Note: Colored outline represents person who will assist primary owner of block Data ABS Actuator User Control And Feed Back

  16. Power Allocation Table Total current demand for all blocks is 3.5 A.

  17. Block Level Standard Requirements • Power • Battery Charger Circuit • Operating Voltage Range 102 - 132 VAC, rms • Output Voltage Range 13 - 14 VDC • Max Power Consumption 40 W • Max power dissipation 5 W • Voltage Regulation Circuit • Input Voltage Range 7 - 40 VDC • Output Voltage Range 4.8 – 5.2 VDC

  18. Block Level Standard Requirements • Mechanical • Battery Charger Circuit • Max product volume 12.5 x 17.5 x 7.5 cm • Max shipping container volume 13.5 x 18.5 x 8.5 cm • Max product mass 3 kg • Max number of PC boards 1 • Connection to AC Nema Plug UL listed AC line cord • Max shock force 5 G’s • Max shock repetitions 500 • Package moisture resistance Sealed, cellophane wrapping

  19. Block Level Standard Requirements • Mechanical • Battery Pack • Max product volume 9 x 7 x 10 cm • Max height over terminals 11.0 cm • Max product mass 2.00 kg • Quick connects for battery terminals • Environmental • Charging Circuit • Operating Ambient Temperature Range -5 to 40 C • Operating Relative Humidity Range 0 - 100 % • Operating Altitude Range all earthly elevations

  20. Block Level Standard Requirements • Environmental • Charging Circuit • Storage Temperature Range -20 to 40 C • Storage Relative Humidity Range 0 - 100 % • Storage Altitude Range all earthly elevations • Storage Duration Maximum 15 years

  21. Block Level Standard Requirements • Environmental • Battery Supply • Operating Ambient Temperature Range - 20 to 50 C • Maximum Storage Duration 3 years • Operating Altitude range all earthly elevations • Operating Humidity range 0 - 100 % • Storage/ Shipping Altitude Range all earthly elevations

  22. Block Level Standard Requirements Safety and EMC • Charging Circuit • UL listed insulated AC power cord, water resistant rated @ 300 V • Grounding to metal frame of transformer • Transformer UL listed #E50394, CSA certified #LR3902 • Electrical isolation of charging unit achieved by AC transformer • Standards: EN 60335 –1 (household electrical), EN60335-2-29 (battery chargers) • EMC: IEC 61000-4-3(E-field immunity) , IEC 61000-4-6(conducted RF immunity) • Battery Supply • UL 94HB – compliant resin at the material for battery case, optional flame retardant resin complying with UL94V-0

  23. Block Level Standard Requirements Manufacturing • Charging Circuit • Max total parts count 14 • Max unique parts 14 • Max parts and materials cost $100 • Max Assembly/Test Cost $20 • Battery Supply • Maximum materials cost $25

  24. Block Level Standard Requirements Life Cycle • Charging Circuit • Estimated Max Production Lifetime 10 years • Service Strategy Factory replacement • Product life, Reliability in MTBF 15 years • Full warranty period 90 days • Product Disposal Landfill • Battery Pack • Estimated Max Production Lifetime 10 years • Service Strategy Factory replacement • Product life, Reliability in MTBF 3 years • Full Warranty Period 90 days • Product Disposal Recycle

  25. Block Level Performance Requirements User Indicators and Display • Charging Circuit: • Charging LED Indicator, Max Viewing Angle 45 degrees • LED typical intensity 30 mcd Electrical Interfaces • Voltage Regulator • Interfaces battery to 5 VDC bus • Output voltage range @ 25 C Tj 4.8 - 5.2 VDC • Input Voltage Range 7.0 – 40.0 VDC • Max Line Regulation 50 mV • Max Load Regulation 50 mV • Peak Current 2.5 A

  26. Block Level Performance Requirements Mechanical Interfaces • Insulated , UL listed AC cord, rated - 40 C to 90 C, water resistant, 300 VAC • UL listed AC Nema plug rate @ 15 A, 125 VAC • Male/Female Molex connector rated max 250 VDC, 8 amps; charger to battery, battery to 5VDC bus. • Mounting of battery pack nylon grid between bicycle frame • Impact resistant plastic enclosure of charging unit

  27. Block Level Performance Requirements • Charging Circuit: • AC Transformer Primary Range 102 – 132, VAC rms • AC Transformer Secondary Voltage & Current 13.0 V, 3A, rms • Secondary AC Voltage With 10 % Regulation 22.0 VAC, rms • Charging Volt Range 13.6 - 13.8 VDC • Max Charging Current 1.5 A • Charging Temperature Range -5 to 40 C • Charge Method Constant Voltage • Charging Time for Full Capacity 5 hours

  28. Block Level Performance Requirements • Battery Supply: • Nominal Voltage , 6 cells in series 12VDC • Nominal Voltage per cell 1.75 VDC • Nominal Capacity 5 Ah • Internal Resistance < 30 milli • Energy Density range 30 – 40 Wh/kg

  29. Detailed Block Diagram for Power Supply Recharger Transformer 115VAC-12.6VAC 3A NEMA Plug 115VAC 15A Seal Lead Acid Battery Nominal Voltage 12V Nominal Capacity 5Ah UL AC Cord, rated @ 300 V Water resistant Full Bridge Rectifier, 50 VDC 4A Molex quick connects PB 137 Voltage Regulator Zener Diode LED Charging Indicator

  30. Detailed Block Diagram for Power Supply Bus Voltage Regulation Seal Lead Acid Battery Nominal Voltage 12V Nominal Capacity 5Ah 12 VDC Bus Molex quick connects LM7805 5VDC Bus

  31. Battery Charger Circuit

  32. Battery Charger Circuit • Transformer: rated @ 12.6 V rms secondary, 3A rms , circuit operates below rated current, transformer will not overheat. Volt Ampere rating is 18.9 . At 10 % regulation, Vm secondary RMS voltage = 20.79 V • % Regulation = • Full bridge rectifier is rated at 50 VAC and 4A. VDC output of rectifier is given by: • VDC output from bridge is Vo = 13.24 V , Vrms = 14.70 V • Zener diode (12V) senses this voltage. Conducts to illuminate indicator LED

  33. Battery Charger Circuit • AC Nema Plug rated @ 115 VAC, 15A • Insulated AC line cord rated @ 300 V , - 40 to 90 C, water resistant • Smoothing capacitor placed after rectifier, needed to eliminate AC ripple, selected for largest possible capacitor value according to, 120 Hz from rectifier • 10 uF capacitor used to filter used to eliminate high frequency pulses

  34. Battery Charger Circuit • Component Selection • Specifically for charging SLA batteries, output current 1.5 A, constant charging voltage @ 13.7 V • features reverse leakage current less than 10 uA, internal current limiting, virtually indestructible.

  35. Battery Charger Circuit • Using the constant voltage charge method , internal current limit • Employed in float or standby operations. 12 V battery , terminal voltage held between 13.5 and 13.8 V. Charger will adjust current to maintain battery in a fully charged status. Current up to 1.5 A with discharged battery • As battery is charged, reaches max value of 13.7 V, charging current will decrease until full charge status. • Approximate charge time formula : • Charge time is approximately, 4 hours, assuming constant charging current of 1.5 A

  36. Battery Charger Circuit Validation of voltage output : close to ideal, 13.7 VDC

  37. Battery Implementation • Choice between NiMh or Seal Lead Acid, NiMh slightly better energy density • SLA was slightly bigger but much less in cost, offered high capacity rating • SLA designed for use in motive power in cars, trucks, scooters. Performs well in temperature extremes, mistreatment, high drain applications. Ideal for trickle/standby use • Werker WKA12 –5F, manufactured to ISO 9001 standard, main features include 5 Ah rating, 9.6 to 12.6 VDC operating range, 1000 recharging cycles

  38. Battery Implementation Battery Discharge Characteristics @ 25 C

  39. Battery Implementation • Major environmental issue with proper disposal of lead acid battery • Improper disposal, landfill or illegal dumping, cause contamination of soil and water with lead Pb and sulfuric acid H2SO4, contaminate ground water affecting drinking water supply. If batteries are disposed of near rivers, streams, risk for aquatic life. • Customers must contact third party vendor , Ascent Inc., 888-9-ASCENT for proper recycling instructions for Werker SLA battery. • Ascent Inc., will recycle by separating lead plates, polypropylene case, which are reclaimed, used in new batteries. Sulfuric acid chemically neutralized.

  40. 5V Voltage Regulation Circuit • 100 uF cap for stabilizing input voltage , noise reduction; 0.1 uF cap for reducing high frequency noise.

  41. 5V Voltage Regulation Circuit Voltage Regulator Selection • Commonly employed in microprocessor applications to provide precise 5 VDC, used with heat sink • Input voltage range 7.3 to 35 VDC, able to handle operating voltage range from battery • Maxmimum load and line regulation 50 mV, met performance requirement • Output voltage within specified range , 4.8 to 5.2 VDC, verified by Spice simulation using +80%, -20% tolerance capacitors, cap values range from 1.8 of nominal ; min value 0.8 of nominal

  42. 5V Voltage Regulation Circuit Worst Case Analysis

  43. 5V Voltage Regulation Circuit Worst Case Analysis Validation of LM7805 Output Voltage Ripple

  44. Reliability Analysis 14.3 years Greatest fits risk is SLA battery which is cannot be eliminated from design

  45. Obsolescence Data No items are obsolete, except for the LM7805 which is in the phase-out period Improvement could be made by choosing a different package, variable voltage

  46. Production Bill of Materials Final production cost is below to original estimate of $120

  47. Battery Charger Internal View

  48. Battery Charger External View

  49. Block Ownership Key Power Supply Eric Graves Richard Roh Block Connection Key David Mapes 120 VAC Nick Bertrand +12 VDC Mark Adamak +5 VDC System Sensors/ LCD Microcontroller Note: Colored outline represents person who will assist primary owner of block Data ABS Actuator User Control And Feed Back

  50. Microcontroller Block Overview • This block provides the means for which the ABS system is controlled. • The sensor, user interface and ABS actuator blocks were built around this central control block. • All of the communication signals for the project were dictated by communication requirements of the microcontroller.

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