Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
  • G01P21/00—Testing or calibrating of apparatus or devices covered by the preceding groups
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
  • B60W40/02—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to ambient conditions
  • B60W40/06—Road conditions
  • B60W40/076—Slope angle of the road
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
  • G01C9/00—Measuring inclination, e.g. by clinometers, by levels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2520/00—Input parameters relating to overall vehicle dynamics
  • B60W2520/10—Longitudinal speed
  • B60W2520/105—Longitudinal acceleration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2530/00—Input parameters relating to vehicle conditions or values, not covered by groups B60W2510/00 or B60W2520/00
  • B60W2530/10—Weight

Definitions

• the present invention relates to a method for validating a measurement of the acceleration ⁇ mes provided by an accelerometer in a motor vehicle. It also relates to an application of said method to the estimation of the slope p of a road on which said motor vehicle moves.
• the invention finds a particularly advantageous application in the field of control of the powertrain (GMP) of motor vehicles.
• the control of the powertrain of a motor vehicle must take into consideration a number of parameters that contribute to the resistive force applied to the vehicle and therefore tend to oppose its movement.
• aerodynamic disturbances such as air penetration and turbulence, friction between the vehicle wheels and the road, as well as those resulting in a loss of efficiency of the power train, and aerodynamic disturbances can be distinguished.
• slope effects such as the slope of the road.
• An object of the invention is to provide an estimator of the slope of the road by measuring the absolute acceleration of the vehicle in the Galilean coordinate system.
• a technical problem to be solved by the object of the present invention is to propose a method for validating a measurement of the acceleration ⁇ mes provided by an accelerometer in a motor vehicle, which would make it possible to obtain a diagnosis of coherence. on the value ⁇ mes measured by said accelerometer and in particular to detect that the acceleration thus measured, and therefore the estimated value of the slope, is erroneous beyond a tolerable limit.
• the solution to the technical problem posed consists, according to the present invention, in that said method comprises the steps of: measuring, in a freewheel phase, an acceleration ⁇ o mes by means of said accelerometer,
• the method according to the invention is based on the verification of the coherence between the value ⁇ o mes of acceleration measured by the accelerometer in freewheeling phase and the value ⁇ o m of redundancy resulting from the model of the freewheeling vehicle. . If this consistency is verified, at the residue threshold, the absence of fault of the accelerometer is then diagnosed and, therefore, the acceleration values it provides can be validated.
• the present invention relates to an application of said method to the estimation of the slope p of a road on which said motor vehicle moves.
• the average value of estimated values of the slope p is validated if the standard deviation on said estimated values is lower than a given threshold, for this the average value of the slope p is compared with a given threshold.
• FIG. 1 is a block diagram of the method according to the invention.
• FIG. 2 is a diagram of a device for implementing the method of FIG. 1.
• FIG. 1 is a diagrammatic representation of a method for validating a measurement of the acceleration ⁇ m ⁇ S provided by an accelerometer in a motor vehicle.
• said method consists, during freewheeling phases of the vehicle, to compare the acceleration ⁇ o m ⁇ S measured by the accelerometer with a value ⁇ o m of the acceleration calculated by means of a model freewheel and vehicle parameters. If the difference between these two accelerations is less than a given residue r, the accelerometer is considered as having no defect, and the acceleration ⁇ mes measured are validated and used in particular to calculate the slope p of the road on which moves the vehicle.
• the accelerometer can be modeled by the following relation:
• Yacc represents the absolute acceleration applied to the accelerometer in the vehicle and ⁇ mes the acceleration effectively measured by the accelerometer.
• the parameters o aC c and ⁇ a are representative of the defects of the accelerometer: o aC c corresponds to the offset of the accelerometer and ⁇ a is the gain on the measurement of the acceleration.
• V eh CGMP - Cokn - RMgp - sign (v ve h) .C e ⁇ t
• J and M represent the total inertia and the mass of the vehicle and R the radius of the wheels.
• Y veh and v veh are respectively the longitudinal acceleration and speed of the vehicle relative to the road.
• CGMP, Cf rem and C ex t are respectively the GMP torque at the wheel, the brake torque and the torque related to the friction,
• p is the slope of the road and is worth sin ⁇ if ⁇ is the angle of the road relative to the horizontal, g is the acceleration of gravity .
• Yacc is C ⁇ / (MR).
• ⁇ m a value of this acceleration, which will be noted ⁇ m , from an estimate C ⁇ mes of the couple engine supplied by the engine and the nominal values M m and R m of mass and wheel:
• r be the residue defined as the difference between the value ⁇ mes of the absolute acceleration provided by the accelerometer and the value ⁇ m calculated according to the model of the vehicle:
• the defects that can be detected are of two kinds: - the Oa offset of the sensor, - an assembly comprising, on the one hand, the gain of the accelerometer and, on the other hand, the errors on the mass, the wheel radius, the GMP torque and the braking torque.
• the detection of a defect equivalent to an offset can be done when the actual absolute acceleration ⁇ acc of the vehicle is zero, that is to say when the torque CT is zero. This situation occurs when the engine torque and the braking torque are equivalent or simultaneously zero. However, according to a usual driving of a motor vehicle, it is unlikely to see a situation in which the engine torque is equivalent to the braking torque, so that the detection of the offset defect is obtained when C G MP and C fre i n are simultaneously zero, therefore when the vehicle is coasting.
• the value of the slope p thus obtained is itself subjected to validation operations.
• an average of the estimated slope values is calculated over a given period of time, then this average value is validated if the standard deviation on said estimated values is less than a given threshold. Similarly, the average value is compared to a given threshold.
• a device for implementing the acceleration measurement and slope estimation validation method is shown in FIG. 2.
• an accelerometer 100 for measuring the absolute acceleration ⁇ mes of the vehicle, as well as a freewheel phase detection block 200 which is intended to ensure that the conditions for calculating the acceleration ⁇ o m according to the freewheeling model are well satisfied.
• the block 200 receives information concerning the absence of a propulsion torque and, more precisely, on the state of the clutch, via means 210 capable of detecting either that the clutch is in position. open for a controlled gearbox, that the clutch pedal is in the depressed position for a mechanical gearbox.
• the block 200 also receives information from an absence of braking detection means 220 comprising means for detecting the brake pedal in the released position, or a means for comparing the pressure of the braking circuit with a threshold given.
• a means 230 for measuring the speed of the vehicle transmits its information to the block 200 in order to compare it to a given threshold (1 km / h for example) and to make sure that the vehicle is in motion.
• Block 300 relates to stopping calculations when they are not checked. This is mainly lateral acceleration information that must remain below a given threshold. This information is provided by a means 310 which can be either another accelerometer or a means of calculation from the vehicle speed and the steering wheel angle.
• a means 320 for detecting the direction of travel informs the block 300 of a possible change in the direction of travel.
• the data from the accelerometer 100 and blocks 200, 300 are then sent to a computer 400 which performs the validity and estimation control operations to output an average value of the absolute acceleration ⁇ m ⁇ S itself validated if the standard deviation is low.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Automation & Control Theory (AREA)
• Mathematical Physics (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Electric Propulsion And Braking For Vehicles (AREA)
• Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)

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Family Cites Families (5)

• 2005
  • 2005-10-21 FR FR0553198A patent/FR2892520B1/fr not_active Expired - Fee Related
• 2006
  • 2006-10-11 WO PCT/FR2006/051018 patent/WO2007045787A1/fr active Application Filing
  • 2006-10-11 EP EP06820280A patent/EP1938111A1/de not_active Withdrawn

Non-Patent Citations (1)

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