An Overview of Vehicle Control Systems


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An Overview of Vehicle Control Systems

  1. 1. Vehicle Control SystemsVehicle Control Systems An Overview of Behzad Samadi Department of Electrical Engineering Amirkabir University of Technology
  2. 2. Vehicle Control Systems 2 Vehicle Control SystemsVehicle Control Systems  ABS  TCS  ESP  4WS  EPS  Active Suspension  AWD  Drive by Wire  ANC  AEM  ACC  S&G  ACA  OW  LW  A/F Ratio Control  Knock Control  Idle Speed Control  Variable Compression Engine  VVT  ATC  CVT
  3. 3. Vehicle Control Systems 3 Antilock Braking System (ABS)Antilock Braking System (ABS) 1. Reduce stopping distance. 2. Maintain steerability. 3. Maintain lateral stability.
  4. 4. Vehicle Control Systems 4 The Operation of ABSThe Operation of ABS  Minimize stopping distance.  Maximize tire-road adhesion with wheel slip control.
  5. 5. Vehicle Control Systems 5 The Operation of ABSThe Operation of ABS
  6. 6. Vehicle Control Systems 6 ABS ComponentsABS Components  Wheel speed sensors.  Electronic control unit.  Hydraulic modulator.
  7. 7. Vehicle Control Systems 7 Wheel Speed SensorWheel Speed Sensor Construction  Magnetic core with surrounding coil. Operation  Magnetic field changes as toothed gear wheel rotates.  AC signal frequency depends on wheel speed.  ECU senses signal and converts it to a square wave.
  8. 8. Vehicle Control Systems 8 ABS in Action!ABS in Action!
  9. 9. Vehicle Control Systems 9 Traction Control System (TCS)Traction Control System (TCS)  Traction control prevents a vehicle's wheels from spinning excessively while on slippery surfaces.  Traction control is intended as a driver aid which allows a vehicle to make better use of available traction on slippery surfaces.  It shares many of the mechanical and electronic elements of the ABS.
  10. 10. Vehicle Control Systems 10 How TCS Works?How TCS Works? Depending on the type of traction control system fitted to the vehicle, wheel spin is controlled by one or a combination of the following:  Brake application at one or more wheels.  Closing the throttle.  Retarding the spark.  Fuel cutout.  Leaner air/fuel ratio.
  11. 11. Vehicle Control Systems 11 TCS in Action!TCS in Action!
  12. 12. Vehicle Control Systems 12 Electronic Stability ProgramElectronic Stability Program  The electronic stability program helps improve cornering and control. By monitoring the slip at the wheels as well as the driver's steering and braking inputs, ESP can sense differences between the driver's intentions and the vehicle's direction in turns.
  13. 13. Vehicle Control Systems 13 ESP PerformanceESP Performance
  14. 14. Vehicle Control Systems 14 ESP OperationESP Operation
  15. 15. Vehicle Control Systems 15 ESP OperationESP Operation
  16. 16. Vehicle Control Systems 16 ESP ComponentsESP Components A) active wheel speed sensors B) steering angle sensor C) combined yaw rate sensor/lateral accelerometer D) attached electronic control unit (ECU) E) motor F) pressure sensor G) hydraulic unit
  17. 17. Vehicle Control Systems 17 ESP ComponentsESP Components
  18. 18. Vehicle Control Systems 18 Automakers & Stability ControlAutomakers & Stability Control  Audi: electronic stability program (ESP).  BMW: dynamic stability control (DSC).  DaimlerChrysler: electronic stability program (ESP).  Ford motor company: advance Trac.  General motors: active handling system (corvette), precision control system (Oldsmobile), Stabilitrak (Pontiac, Buick, Cadillac).  Jaguar: dynamic stability control (DSC).  Lexus: vehicle skid control (VSC)  Porsche: Porsche stability management (PSM).  Volkswagen: electronic stability program (ESP).  Volvo: dynamic stability traction control (DSTC).
  19. 19. Vehicle Control Systems 19 ESP in Action!ESP in Action!
  20. 20. Vehicle Control Systems 20 Four Wheel SteerFour Wheel Steer  Improve low-speed maneuverability.  Smallest possible turn radius.  Improved handling at high-speed.  Increased vehicle stability.
  21. 21. Vehicle Control Systems 21 Electric Power SteeringElectric Power Steering  Reduced engine drain.  Improved fuel economy and acceleration.  Instant-on power steering.  Added dependability and assist even with engine off.
  22. 22. Vehicle Control Systems 22 Active SuspensionActive Suspension  Active suspension systems move each wheel up and down to control body motion in response to road abnormalities.  With an active suspension, a vehicle can simultaneously provide the smooth ride of a soft suspension along with superior handling associated with a firm suspension.
  23. 23. Vehicle Control Systems 23 Active Body ControlActive Body Control
  24. 24. Vehicle Control Systems 24 Dynamic Body ControlDynamic Body Control
  25. 25. Vehicle Control Systems 25 Active Body ControlActive Body Control
  26. 26. Vehicle Control Systems 26 Suspension Control in Action!Suspension Control in Action!
  27. 27. Vehicle Control Systems 27 Suspension Control in Action!Suspension Control in Action!
  28. 28. Vehicle Control Systems 28 All Wheel DriveAll Wheel Drive  When accelerating, weight shifts to the rear, reducing traction in front and AWD direct power to the rear wheels.  When braking, weight shifts forward, reducing traction in back. With AWD, power is instantly directed to the front wheels for better steering control and braking performance.
  29. 29. Vehicle Control Systems 29 All Wheel DriveAll Wheel Drive  Whether icy, oily, wet, or rough, if front wheels start to slip, AWD system instantly directs power the rear wheels; If rear wheels start to slip, power is directed to the front wheels.  The power is automatically transferred to the wheels with the best traction. Unwanted understeer and oversteer is virtually eliminated.
  30. 30. Vehicle Control Systems 30 Drive by WireDrive by Wire  Replacement of traditional mechanical systems for steering, braking, throttle and suspension functions, with electronic controller, actuators and sensors.
  31. 31. Vehicle Control Systems 31 Brake by WireBrake by Wire  The braking process is triggered in the conventional manner by the brake pedal; In the process, the pedal pressure and pedal travel are measured by sensors and converted into electronic signals for the electronic control unit (ECU). The unit that is activated in this way controls the four actuators at the wheel brakes. The brake pads are therefore forced together and opened electromechanically and no longer hydraulically.
  32. 32. Vehicle Control Systems 32 Sensotronic Brake ControlSensotronic Brake Control  Mechanical components are replaced by electronics.  Sensors pass the master cylinder pressure and the speed with which the brake pedal is operated, to the SBC computer.  To provide the driver with the familiar brake feel, a special simulator is linked to the tandem master cylinder.  Only in the event of a major fault or power failure does SBC instantly establishes a direct hydraulic link between the brake pedal and the front wheel brakes.
  33. 33. Vehicle Control Systems 33 Sensotronic Brake ControlSensotronic Brake Control
  34. 34. Vehicle Control Systems 34 Sensotronic Brake ControlSensotronic Brake Control
  35. 35. Vehicle Control Systems 35 Steer by WireSteer by Wire  Steer-by-wire system eliminates the mechanical connection between the driver and the vehicle’s front tires. The traditional steering elements are replaced by two actuators positioned in the vehicle’s front corners. These actuators receive input from the control module and turn the front wheels accordingly. The system also uses an electric motor to provide road feedback to the driver’s hand wheel.
  36. 36. Vehicle Control Systems 36 Electronic Throttle ControlElectronic Throttle Control  Electronic throttle control (ETC) replaces the throttle cables that run from the accelerator pedal to the engine.
  37. 37. Vehicle Control Systems 37 Active Noise ControlActive Noise Control  Traditionally noise is controlled by passive methods: enclosures, barriers and silencers.  Active control is used when passive noise control methods don’t work.  Secondary sources are used to cancel noise from primary source(s) by introducing “antinoise”.
  38. 38. Vehicle Control Systems 38 Active Vibration ControlActive Vibration Control  The primary way to cut off paths of noise and vibration from engine is to use soft mounts. However, engine mounts must also constrain or control engine excursions caused by rough roads, firing in cylinders, wheel torque reactions, etc. To limit engine motions, the engine mounts should be stiff and heavily damped. These conflicting requests on engine mounts have prompted automotive industries to search for a new engine mounting method.
  39. 39. Vehicle Control Systems 39 Cruise ControlCruise Control  The cruise control system controls the speed of your car the same way you do by adjusting the throttle position.
  40. 40. Vehicle Control Systems 40 Adaptive Cruise ControlAdaptive Cruise Control  Adaptive cruise control (ACC) improves on traditional cruise control by allowing a vehicle to automatically adapt to the speed of highway traffic.
  41. 41. Vehicle Control Systems 41 Stop and GoStop and Go  The Stop & Go function maintains longitudinal car control at low speeds, e.g. when queuing on a motorway or waiting at a traffic light.
  42. 42. Vehicle Control Systems 42 Anti Collision AssistAnti Collision Assist  This system helps prevent collisions by sending the driver an acoustic or visual signal to warn of the presence of standing or slow-moving obstacles in the car's path. The system also acts on the car's brakes when necessary.
  43. 43. Vehicle Control Systems 43 Overtaking WarningOvertaking Warning  The blind spot coverage sensor warns of the presence of vehicles about to enter the side area not covered by the door mirrors. The sensor turns on a warning light, which can be used in conjunction with the door mirror. The warning signal becomes acoustic when the turn signal is activated.
  44. 44. Vehicle Control Systems 44 Lane WarningLane Warning  This additional driving support function automatically detects car position in relation to lane boundaries. The system issues an advance warning if the car inadvertently crosses the lane boundaries. The road in front of the car is filmed by a micro TV camera and the driver may select between tactile or acoustic indicators.
  45. 45. Vehicle Control Systems 45 Engine Control SystemsEngine Control Systems
  46. 46. Vehicle Control Systems 46 Engine Control SystemsEngine Control Systems
  47. 47. Vehicle Control Systems 47 Air/fuel Ratio ControlAir/fuel Ratio Control  A fuel injector is an electronically controlled valve. It is supplied with pressurized fuel by the fuel- pump in your car.  Two different injection systems: • Manifold injection. • In-cylinder injection.  Lambda: 14.7:1
  48. 48. Vehicle Control Systems 48 Effects of Air/fuel RatioEffects of Air/fuel Ratio
  49. 49. Vehicle Control Systems 49 Effects of Air/fuel RatioEffects of Air/fuel Ratio
  50. 50. Vehicle Control Systems 50 Knock ControlKnock Control  Self inflammation of the air fuel mixture. • Increased ambient temperature. • Increased load pressure. • Bad fuel quality.  Usual actuation is a retardation of the ignition angle.  An alternative input: reduce boost pressure of turbo charger.
  51. 51. Vehicle Control Systems 51 Idle Speed ControlIdle Speed Control  If the idle speed is unstable, unpleasant vibrations or engine breakdown when started may occur, or fuel economy may drop.  As a rule of thumb, fuel consumption increases proportional to engine speed at idling.  The actuation variable at SI engines is the mass air flow into the engine, at diesel engines the injected fuel amount.
  52. 52. Vehicle Control Systems 52 Saab’s Variable CompressionSaab’s Variable Compression EngineEngine  Improves fuel efficiency by up to 30 percent, reduces tailpipe emissions, and doesn't negatively impact overall performance.  The SVC engine's cylinders are located in the upper section.  By adjusting the "slope" of the upper part of the engine in relation to the lower part by the use of hydraulic actuators, the Saab engine can vary the volume of the combustion chambers. This, in turn, changes the compression ratio.
  53. 53. Vehicle Control Systems 53 Variable Valve TimingVariable Valve Timing  Valve timing changes with operating conditions such as engine speed and throttle position.  The engine can rev higher, thus raises peak power. For example, Nissan's 2- liter neo VVL engine output 25% more peak power than its non-VVT version.  Low-speed torque increases, thus improves drivability. For example, fiat Barchetta's 1.8 VVT engine provides 90% peak torque between 2,000 and 6,000 rpm.
  54. 54. Vehicle Control Systems 54 Variable Valve TimingVariable Valve Timing
  55. 55. Vehicle Control Systems 55 Adaptive Transmission ControlAdaptive Transmission Control  ATC adapts transmission shift parameters according to individual styles of driving (e.g. aggressive vs. relaxed)  Improves shift consistency and transmission durability and allows for shifting that is better suited to specific driver styles or operating conditions
  56. 56. Vehicle Control Systems 56 Continuous Variable TransmissionContinuous Variable Transmission  An infinite number of gear ratios to optimize performance and fuel efficiency.  There are no more gear shifts as such, which makes the CVT a highly sophisticated gearbox for high levels of driving comfort.  The metal-link push belt permits high torques of up to 400 nm to be transferred.  The CVT's high gear ratio spread permits the engine to be operated in the low- consumption speed range.
  57. 57. Vehicle Control Systems 57 ...‫دفتر‬ ‫اين‬ ‫آمد‬ ‫پايان‬ ‫به‬...‫دفتر‬ ‫اين‬ ‫آمد‬ ‫پايان‬ ‫به‬