Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
  • G01L5/20—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring wheel side-thrust
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D3/00—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups
  • G01D3/02—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups with provision for altering or correcting the law of variation
  • G01D3/021—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups with provision for altering or correcting the law of variation using purely analogue techniques
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T2240/00—Monitoring, detecting wheel/tyre behaviour; counteracting thereof
  • B60T2240/03—Tyre sensors

Definitions

• the invention relates to a method and a control circuit for detecting and evaluating driving-dynamic states of a motor vehicle by means of wheel force sensors, preferably with tire sensors, which, as a measure of the transverse forces acting on the wheel or the tire, determine the preset air gap between at least one rotating encoder and at least one measurement sensor use.
• a tire sensor (SWT sensor) is understood here to mean the encoder mounted in or on the tire and at least one at least one measuring value sensor assigned to the encoder and arranged stationary on the chassis. While in EP 04 441 09 B1 the deformation of the tire tread area of the tire - the tire flap - is monitored, in WO 96/10505 the deformation of the sidewall - the torsional deformations - of a tire is measured over a period of time between passing at least two on a different radius Marks of rotation of marks arranged on the rotating wheel are detected.
• WO 97/44673 describes a tire sensor which detects a change in the phase position and / or the amplitude between output signals emitted by measurement sensors when the tire is deformed as a result of the forces acting on the tire.
• the size of the air gap between the encoder or the magnetic areas embedded in the tire sidewall and the, for example, active, magnetoresistive transducers form the signals that are used to assign the ones acting on the tire Lateral or transverse forces can be used.
• the changes in the signals determined by the transducer consequently represent the deformations or changes in the tire sidewall which arise due to the transverse forces acting on the wheels, while the change in the phase position between the two is arranged on an outer and an inner radius to the axis of rotation of the wheel Define a sensor for the calculation of the longitudinal forces.
• measuring rims are used, as described by way of example in EP 0 352 788 A2. It is necessary to arrange the transducers on the chassis or the wheel suspension in order to make the signals dependent on the air gap reproducible. Tolerances and / or different rim systems resulting from the arrangement or production of the transducers, e.g. with different press-in depths lead to deviations in the determination of the forces acting on the wheels or tires.
• the invention is based on the object of enabling an error-reduced evaluation of wheel forces, in particular of deformations of the rim and / or the tire detected by means of tire sensors. According to the invention, this object is achieved by the features of the independent claims. Dependent claims are directed to preferred embodiments.
• the preset air gap between at least one rotating encoder and at least one transducer can be used to measure and evaluate the driving dynamics of a motor vehicle by means of wheel force sensors, preferably with tire sensors, as a measure of the lateral forces acting on the wheel or tire.
• wheel force sensors preferably with tire sensors
• the operating point of the output signal of the sensor or a e.g. the signal processing device downstream of the transducer is set regardless of its default setting, the output signal can be processed with reduced errors without loss of signal quality, since it is determined independently of this preset distance between the transducer and encoder. Rims with different press-in depths but with the same rigidity can be used.
• the distance between the transducer can be varied as desired over the resolution range without the need to adapt the functional mapping between the amplitude and the lateral force.
• a generic control circuit is designed in such a way that for the detection and evaluation of driving dynamic conditions of a motor vehicle by means of wheel force sensors, preferably with tire sensors, which, as a measure of the transverse forces acting on the wheel or the tire, the preset air gap between at least one rotating encoder and at least one Use transducers, they contain a determination unit that determines the operating point of the output signal of the Sensor or a signal conditioning device sets regardless of its default.
• the invention provides for the method and the control circuit to be designed in such a way that the output signal is adapted to the vehicle-specific distances between the sensor and the encoder.
• An expedient method and a control circuit are characterized in that the output signal is standardized to at least one nominal value in the case of stationary, longitudinal or lateral force-free driving behavior.
• the stationary, longitudinal or lateral force-free driving behavior is determined with the aid of input variables which are provided by conventional sensors and which comprise at least the lateral acceleration, the longitudinal acceleration and the steering wheel speed. At this point in time, little or almost no longitudinal or transverse forces suitably act on the wheel or the tire.
• the following conditions can be used individually or in any combination for a stationary, longitudinal and lateral force-free driving behavior:
• the output signal provided by the transducer or a signal processor is a sinusoidal AC voltage or current signal, the nominal value of which is determined with every peak value of the half-wave (amplitude) or with every change of the poles or brands of the encoder, if the conditions of the stationary driving behavior are fulfilled.
• the nominal value is assigned a value which represents the zero point (offset) of the lateral force acting on the wheel and / or the tire.
• the lateral forces are then determined during dynamic states of the vehicle as a function of the amplitude changes according to the relationship
• the control circuit 10 which is connected to a magnetic field-sensitive transducers 13, 14 arranged at a radial distance of two m from the axis of rotation 11 of the wheel 12 on the chassis of a motor vehicle.
• the control circuit can be part of the transducers or a separate unit or part of ABS (anti-lock control system), ASR (traction control system), ESP (electronic driving stability control system), EHB (electro-hydraulic brake control system), a chassis control system and / or an EMB (electro-mechanical brake system). ) Control system.
• the vehicle tire 15 has an encoder 17 with permanent magnetic areas with changing polarity N, S.
• the permanent magnetic areas N, S are embedded in the tire wall 18 of the wheel 12.
• a distance is preset between the encoder 17 and the transducers 13, 14 (air gap 20).
• the measurement signal is amplified by a sensor-integrated electronic circuit and converted into an output signal.
• the operating point of the output signal of the measurement sensor 13, which is dependent on the air gap 20, is set in a determination unit 21 independently of the presetting.
• the output signal is normalized to a nominal value when the vehicle is stationary, and the nominal value is correlated with the lateral force zero point via means 21. Then there is a reproducible relationship between the change in the amplitude signal and the change in the lateral force.
• the sinusoidal output signal which is created by the action of the encoder 17 on the magnetic field-sensitive transducer 13 and whose peak value varies with the air gap 20, can be an AC voltage signal or an AC signal.
• the alternating current signal can be transformed into an alternating voltage signal in a signal processing device assigned to the transducer 13.
• Figures 3 and 4 show the relationship between the air gap 20 and the amplitude signal of the transducer 13, in a non-linear, almost exponential form.
• the voltage of the output signal (sensor voltage) is plotted over the air gap 20
• FIG. 3 the output signal, DC voltage and sign corrected, is plotted over the air gap.
• the method according to the invention works as follows:
• the driving behavior is monitored with signals from conventional sensors, such as and longitudinal acceleration sensors, yaw rate sensors, steering angle sensors and the like, determined, since the adaptation of the amplitude signal to the air gap 20 should only take place under steady-state conditions.
• conventional sensors such as and longitudinal acceleration sensors, yaw rate sensors, steering angle sensors and the like.
• the driving behavior is stationary, without longitudinal or lateral force.
• the amplitude signal is then normalized to a nominal value with each peak value of the half-wave or with each change of the magnetic areas N, S or poles or marks of the encoder 17.
• This nominal value is correlated with a transverse force zero point or force offset, which was determined almost simultaneously with a force measuring element, preferably a measuring rim, under the influence of the forces occurring on the wheel 12.
• the lateral force value is ideally 0 N for stationary driving behavior.
• the transverse forces in dynamic states of the vehicle become dependent on the amplitude changes Amp Nulzw ⁇ rl according to the relationship
• Amp output signal (amplitude)
• Amp Nen nw ert standardized output signal (nominal value)
• Amp Nutzwer t ratio of the amplitude and the standardized nominal amplitude.
• the amplitude changes can be based on distance changes according to the relationship
• the transverse forces can then essentially be determined as a function of the changes in distance.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Technology Law (AREA)
• Force Measurement Appropriate To Specific Purposes (AREA)

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• 2000
  • 2000-09-14 WO PCT/EP2000/008989 patent/WO2001019654A1/de not_active Ceased
  • 2000-09-14 EP EP00964171A patent/EP1216175B1/de not_active Expired - Lifetime
  • 2000-09-14 JP JP2001523256A patent/JP2003509665A/ja active Pending
  • 2000-09-14 US US10/088,193 patent/US6988395B1/en not_active Expired - Fee Related

Patent Citations (3)

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