JP2003525814A - System and device for detecting yawing motion with redundant measurement channels - Google Patents

Abstract

(57) Abstract: Inspection of at least two independent measurement channels (11, 12) having independent sensors (TR1, YR2, AX, AY) and malfunction or failure of the measurement channels (5, 8). And a means for detecting safety-critical measurands, in particular yaw rate and / or acceleration data of the vehicle, so that the sensors are operated in parallel without restriction. By using sensors that are not identical, the first measurement channel (11) and one or more other measurement channels (12) are operated with high-temperature redundancy. The device comprises a sealed casing (2) with a plug (9), wherein the sealed system surrounds the aforementioned system.

Description

Detailed Description of the Invention

The present invention relates to a system and a device for enhancing the characteristics of a device for detecting yaw movement in a motor vehicle system with a controlled brake. This is, for example, an automatic driving stability control system (ESP) associated with an anti-lock brake control system (ABS), a traction slip control system (TCS) and a steering correction system, but an automatic cruise control system (AICC) or It may be a collision avoidance system.

Driving stability control systems (ESP) for controlling and limiting undesired yawing movements about a vertical axis are known. In this case, an important variable that can be deliberately changed by the driver is measured by the sensor and the target yaw rate is calculated based on it. The variables are steering angle, accelerator pedal position,
Braking pressure, lateral acceleration and individual wheel rotation. At the same time, the actual value of the yaw rate that occurs in response to the driving maneuver is measured by the yaw rate sensor. If the actual value of the yawing movement differs from the calculated target value such that it exceeds a predetermined degree that jeopardizes driving stability, then appropriate braking and engine interventions will limit the yawing movement to an acceptable value.

High functional reliability is required by the sensor. Because the malfunction of the sensor
This is because in some circumstances braking / de-braking can occur at the wrong time, which can lead to dangerous situations. This is especially true for yaw rate sensors. In the case of this yaw rate sensor, an undesired control action can occur if the permissible drift error in terms of accuracy and precision is significantly exceeded. Despite the effects of this control process can be governed by the use of other auxiliary variables, causality or adequacy criteria, today's automotive industry increases the intrinsic safety of yaw rate sensor devices and Prioritized attempts have been made to ensure that undesired control processes caused by a faulty yaw rate sensor are closed, without the use of auxiliary variables, causal relationships or adequacy criteria. Automotive yaw rate sensors according to the current state of the art already have a high degree of intrinsic safety and are designed in most cases to manifest themselves as a given total failure. However, there remains a small chance that a slow-moving defect will not be recognized. Such defects are eg defective capacitors, high resistance open semiconductor inputs, intermittent contacts, etc. The possibility of sensor failure is
The isolated sensor can be shown on the manufacturer's side. However, this so-called intrinsic safety of the sensor does not meet the requirements of the automobile industry.

The demand can be estimated according to the following calculations. Assuming that 10 million cars are manufactured and supplied to the market per year and the average driving time of the car value is estimated to be 4500 hours, the probability of failure of the yaw rate sensor is about 10 ^-7 .

Conventional vehicle yaw rate sensors do not currently meet the demand for such a small failure probability. Therefore, there is a need to provide a unit for a yaw rate sensor system with high intrinsic safety.

[0006] It is an object of the present invention to provide a system or device that meets the aforementioned high demands.

[0007]   This problem is solved by the system according to claim 1.

The system according to the invention for detecting safety-critical measurement quantities, in particular motor vehicle yaw rate and / or acceleration data, has at least two independent measurement channels with sensors that are independent of one another and a malfunction of the measurement channels. Or it includes means for checking for faults.

In the system according to the invention, the first measurement channel and one or more other measurement channels are operated with a high degree of redundancy. This uses, in the present invention, similar, but not identical, sensors, as will be described below, so that the sensors can be operated in parallel without limitation (which is understood, for example, as an unlimited measuring range). Means that.

Similar sensors are, in the present invention, sensors that operate on the same physical principle. This is, for example, a vibration sensor or a laser sensor in which the resonant frequencies of the vibrating elements differ, or sensors of all physical types belonging to the same accuracy class.

According to the invention, the sensors used are not exactly the same. As will be explained below, the sensors are distinct from each other, at least in their fundamental vibration mode, so that inductive interference from one sensor to the other is blocked and that mechanical or electromagnetic disturbances do not act on the sensor in the same way. ing.

The term “accuracy class” in the sense of the invention means that the deviation of the measured values of the sensor is within the accuracy interval (percentage deviation with respect to the final value indicated within the measuring range) set in a certain accuracy class. Is understood to be.

The various redundancies used in the present invention are Gellert,
Lexikon's dictionary of mathematics by Kaestner and Neuber
der Mathematik), II Theory of Reliability (Zuverkaessigkeitstheorie), p. 470, published by the VEB Biblographisches Institut, Leipzig, 1985, and automation by Helm, Dr. Prangt. Technical guide (Lehrbuch der Automatisierungstechnik), pages 88-90, reliability characteristic / redundancy (Zuverlaessigkeitskenngroessen / Redundanz), VEB technology (V
Published by EB Technik), Berlin, 1965.

The term redundancy is used in connection with the incorporation of additional elements (eg measurement channels) to increase the reliability of technical systems. "Cold redundancy" is used when the spare element (eg, spare channel or spare sensor) is not exposed to stress under normal operating conditions. In contrast, "hot redundancy" is used when the spare element is under normal operating conditions and under the same stress as the working element. Low temperature and high temperature redundancy are the limiting cases of "warm redundancy" where the spare element is less stressed than the working element.

In the case of the sensors usable in the present invention, the system, which is preferably the first yaw rate sensor, comprises at least one other yaw rate sensor and optionally other sensors such as an acceleration sensor. .

The application of redundancy considerations in the field of vehicle sensor systems is known per se for increasing the reliability of technical systems. German Patent Application Publication No. 1952521
No. 7 proposes a method and a device in which the yaw rate as an input quantity of a vehicle control system is obtained by means of two independent measuring channels. The one measuring channel detects the entire measuring range and the other measuring channel is adjusted to the partial measuring range. In order to recognize the fault, the output value of the measurement channel is checked whether it matches the measurement value detected by the measurement channel and / or the validity of the measurement result. In this case, the subrange changes dynamically depending on the yawing process or is used as a "loupe". Unlike the present invention (application of "hot redundancy"), the method described in DE-A-195 25217 uses principles consistent with the application of "warm redundancy". In DE-A-195 25 217, part of the use of "high temperature redundancy" is limited to the partial measuring range. In this case, the partial measurement channel has a high degree of accuracy and is therefore of greater measurement technical importance in use than the second measurement channel. There is "cold redundancy" outside the partial measurement range. This is because the partial measurement channel usually remains unused. However, this partial measurement channel can potentially be served dynamically. Therefore, the method proposed according to the invention differs from the method described in DE-A-19525217.

Unpublished German patent application No. 19921692.4 proposes a system for protection against disturbances by electronic functional units and / or functional groups. In this case, the structure groups have different sensitivities to disturbance, and different shields against disturbance are assigned to the structure groups. In this case, two or more shields are added to shield with high efficiency.

[0018]   In the system according to the invention, a yaw rate sensor of any physical working principle, e.g.
For example, a sensor based on the use of laser light can be used. But used yaw
The rate sensor is preferably under yawing motion to estimate yaw rate.
It is a type of sensor that utilizes the Coriolis force of the vibrating element generated in
Vibrating element). Many types of such yaw rate sensors are known. vibration
Elements include cylinders made of silicon or quartz, rings, disks, prisms,
Tuning forks, micro-engineered structures are used. The working principle of this sensor is
, The vibrating element is excited in one direction of the element with constant drive amplitude and frequency,
Under the influence of Rio, mechanical vibrations occur in the other direction of the simultaneous elements,
The amplitude is proportional to the yaw rate. Vibration element is piezoelectric or magnetic conversion method
Is driven (driven) by the method, and the Coriolis reaction is similar piezoelectric or magnetic
Detected by the conversion method (pickup). The drive frequency of the vibration drive device is f _o , The pickup vibration of mechanical vibration in the three-dimensional direction of the Coriolis reaction is shown.
Wave number f_c, The vibration element always has a resonance frequency interval Δf = f between both frequencies. _o -F_cAre mechanically formed so that

The yaw rate sensor with a mechanical vibrating element is in particular a resonant vibration of the vibrating element so that the vibrations do not influence each other and the externally applied vibrations excite or only slightly excite both yaw rate sensors. The difference is that the numbers are separated from each other.

The individual frequencies f _o , f _c of all the redundant yaw rate sensors, if they are mechanically arranged together in a casing or on a common support, the individual sensors of the oscillator or the pick-up signal. Mechanical vibration coupling, which is no longer possible by the active vibration elements and / or the electrical interconnections (eg by frequency attraction or mechanical solid-borne sound coupling).

As mentioned above, the use of “hot redundancy” (unlike other redundancy types) reduces the overall failure rate (unreliability) to the product of the individual failure rates. Similarly, according to the invention, the failure rate of an individual vehicle yaw rate sensor is formed by 70 FIT (which is synonymous with 70 × 10 ⁻⁹ failures per operating time and is in fact a meaningful value). With two different yaw rate sensors, the required characteristics with about 10 ^-7 failure probability are achieved in "high temperature redundancy", under the condition of 10 million vehicles each having a lifespan of 4500 hours. It

In the system, preferably a sensor electronics is connected to the sensor, the output signal of the sensor electronics is evaluated by an electronic processing unit and a connection is provided to the communication interface terminal, the communication interface terminal being at least It can be connected to one central control unit.

In the electronic processing unit, the means for checking the malfunction reports the test result by transmitting an appropriate signal to the communication interface terminal. Thereby, the central control unit (ESP / ECU), which is connected via the communication interface, responds in the event of a sensor failure so that the system can continue to operate, in some cases until first the vehicle is in a safe condition. You can And for the first time, the system can be stopped in whole or in part (ballback concept).

The fault recognition is preferably carried out by continuously comparing the output values of the individual yaw rate sensors and the changing states of these output values with one another in a comparison unit. If the output value and / or its changing state are different from each other and / or different from the acceptance criterion set above the temporarily applicable limit value, the start of the control based on the yaw rate sensor is not allowed. When a system with n high temperature redundancy channels is controlled and a total failure occurs on nm channels during control, the remaining m
Control by this channel is terminated.

It is particularly advantageous if the frequency spacing Δf of the individual sensors is chosen as follows. If two yaw rate sensors with similar accuracy to the measuring range are used, the first sensor is the frequencies f _o1 , f _c1 with the frequency interval Δf ₁ and the second sensor is the frequency with the frequency interval Δf _2. It is particularly advantageous if it is chosen to be f _o2 , f _c2 . In this case, therefore, the frequency intervals are chosen such that no mechanical or electrical common-mode disturbances, which can affect both yaw rate sensors simultaneously in time, occur.

When the frequency spacing is selected as described above, surprisingly, external vibration effects acting on the common sensor casing or the common support by the chassis of the moving vehicle are caused by the yaw rate sensor system according to the invention. Does not cause a breakdown.

The yaw rate sensor can be arranged in a so-called “high temperature redundancy” as a functional block (module) with a common envelope casing.

The invention therefore also relates to a device comprising a sealed casing with a plug, by means of which this casing is enclosed.

The sensor is preferably arranged in a shielding inner casing or box arranged in the casing.

It is expedient if the inner casing or box is not electrically connected to the sealed casing.

The yaw rate sensor is preferably arranged on the first circuit board and at least part of the electronic processing unit is arranged on another circuit board.

Suitably, the first circuit board is arranged in an inner casing or box which is shielded and the other circuit board is arranged outside the inner casing or box which is shielded.

The shielding means used to protect the radiated electrical high frequency against energy is such that both yaw rate sensors or a plurality of yaw rate sensors operating in “high temperature redundancy” simultaneously at this high frequency energy. Avoid being disturbed. Similar shielding means are described in German Patent Application No. 19921692.4. In the known device, disturbances such as electromagnetic radiation, capacitive coupling, etc. act on the yaw rate sensor in different ways, since the individual yaw rate sensors are surrounded by a shielding box or a shielding casing which oscillates different actions.

In a preferred embodiment of the invention, the yaw rate sensor is housed in an inner casing or an inner box arranged in the outer casing, so that the outer casing and the inner casing are shielded.

The device according to the invention has the advantage of providing a combination of a lateral acceleration sensor and a longitudinal acceleration sensor as a compact device with a CAN bus interface.

Additional embodiments and advantageous implementations of the invention will become apparent from the following description of embodiments with reference to the accompanying drawings.

FIG. 1 shows schematically the technical interaction of the components of a system of the kind according to the invention. The system forms a device 1 for simultaneously detecting yaw rate, longitudinal acceleration and lateral acceleration for use in ESP. The device comprises a casing 2, in which the interior chamber contains all components. Between the device and the electronic controller of the ESP device 3 is a CAN bus connection 4
Is provided. The CAN bus controller 5 is a component of the device. The system is structurally provided with two independent measuring channels 11, 12. This measurement channel is a sensor branch that is almost the same. First measurement channel 1
1 includes a yaw rate sensor YR1 having an associated signal processing circuit SC1 and a longitudinal acceleration sensor AX having an associated signal processing circuit SCX. The signals of these sensors are signal-technically preprocessed in the first microcontroller MC1.
To that end, resident software PPSW 7a is provided to allow additional information to be received from the ECU via the CAN bus and connection 6a. Second measurement channel 1
2 is a yaw rate sensor YR2 having a signal processing circuit SC2, and a signal processing circuit SC
A vertical acceleration sensor AY having Y is provided. The signals from these sensors are second
Is pre-processed in signal technology by the microcontroller MC2 of. To that end, resident software PPSW 7b is provided to allow additional information to be received from the ECU via the CAN bus and connection 6b. The preprocessed signals are combined in functional step 8. Here, the redundancy check described above is performed and a corresponding status signal is generated. This status signal informs the ECU if the initiation of control is temporarily allowed or if one of the controlling channels has failed. Since the preprocessed signals YR1, YR2, AX, AY and the status signal of the redundancy check are periodically transmitted to the ECU via the CAN bus, the second redundancy check independent of the ECU can be performed.

FIG. 2A schematically shows the structural design of the device 1. The torsion-resistant casing 2 is made of aluminum. This casing has two tongue pieces 2a and 2b for fixing to the chassis and a CAN bus plug 9. Two printed circuit boards PCB1 and PCB2 are provided inside. YR1 for PCB1
, SC1 and YR2, SC1 are provided. PCB1 is a metal shield box (
It is surrounded by a Faraday box 10. This shield box prevents the intrusion of high-intensity high-frequency radiation (for example in mobile phones) into sensitive yaw rate sensor devices. The PCB 2 contains all the remaining components described in connection with FIG.

The technique of the yaw rate sensor that is advantageously used is based on a micro-engineered structure made of silicon, which takes advantage of the micro-engineered tuning fork of quartz or the Coriolis effect that occurs during rotation. In the present invention, the signal conditioning stages of both acceleration sensors together form a composite unit according to MEMS (Micro Electro Mechanical System). Similarly, in the present invention, the special signal conditioning stages of the yaw rate sensor and the acceleration sensor, one by one, form a composite unit according to the MEMS.

For application in ESP systems, for example, preferably ± 75 to ± 100 ° / s
A yaw rate sensor having a measuring range of is used.

The failure rate of the yaw rate sensor used is preferably up to about 70 FIT.

If two similar yaw rate sensors are used according to the invention (which is advantageous), the mechanical natural frequency of the vibrating element can be selected, for example:

Sensor 1: f _o1 = 12.0 KHz, f _c1 = 12.2 KHz, Δf ₁ = 200 Hz Sensor 2: f _o2 = 12.5 KHz, f _c2 = 12.6 KHz, Δf ₂ = 100 Hz As an acceleration sensor, preferably about ± Elements having a measuring range of 1.5 to about ± 2.0 g are used. In this case, g is the gravitational acceleration.

The acceleration and yaw rate sensors used preferably have a minimum signal quantization of about 10 bits, in terms of signal resolution and noise conditions, in connection with a bandwidth of 50 Hz.

[Brief description of drawings]

[Figure 1]   1 is a schematic view of a device according to the present invention.

[Fig. 2]   FIG. 2a is a diagram schematically showing the structural design of an actual embodiment.   FIG. 2b shows the actual embodiment of FIGS. 1 and 2A in full scale.   FIG. 2c is a diagram in which the coordinates of the embodiment of FIGS. 2A and 2B are adjusted to the vehicle.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), JP, U S (72) Inventor Zidek Michael             Germany, Frankfurt, Two             A Frankenfurt, 53 F term (reference) 3D046 BB01 BB28 BB29 HH21 HH25                       HH26 MM06 MM15

Claims (12)

[Claims] 1. At least two independent measurement channels (11, 12) with independent sensors (TR1, YR2, AX, AY) and for checking malfunction or failure of the measurement channels (5, 8). In a system for detecting safety-critical measured quantities, in particular motor vehicle yaw rate and / or acceleration data, which are equipped with A system characterized in that the first measurement channel (11) and one or more other measurement channels (12) are operated with high temperature redundancy by using sensors which are not identical. 2. The sensor comprises at least one first yaw rate sensor (YR1).
Other yaw rate sensors (YR2) and, in some cases, acceleration sensors (AX,
The system of claim 1 including other sensors such as AY). 3. A sensor electronic device (SC1, SCX, SCY, SC2)
) Is connected and the output signal of this sensor electronics is an electronic processing unit (MC1
, MC2, COMPARE), and the communication interface terminal (C
A system according to claim 1 or 2, characterized in that a connection for an AN CONTROL) is provided, the communication interface terminal being connectable to at least one central control unit (ESP / ECU). 4. The electronic processing unit comprises a comparison unit (COMPARE), which compares the sensor signals of the plurality of yaw rate sensors and the time variation of the signals with one another. The system according to at least one of. 5. The yaw rate sensor includes a mechanical vibration element, and the yaw rate sensor has the following points, that is, the vibrations do not affect each other, and both yaw rate sensors do not vibrate or only slightly vibrate due to externally applied vibrations. 5. The system according to claims 2 to 4, characterized in that the resonant frequencies of the vibrating elements are different in that they are separated from each other. 6. A device comprising a sealed casing (2) with a plug (9), the sealed casing enclosing the system according to at least one of claims 1-5. 7. Device according to claim 6, characterized in that the sensor is arranged in a shielding inner casing or box (10) arranged in the casing (2). 8. The apparatus of claim 7, wherein the inner casing or box is not electrically connected to the sealed casing. 9. The yaw rate sensor is arranged on the first circuit board, and at least a part of the electronic processing units (MC1, MC2, COMPARE) is arranged on another circuit board. 8. The device according to at least one of 8. 10. The circuit according to claim 9, wherein the first circuit board is arranged inside the shielding inner casing or box, and the other circuit board is arranged outside the shielding inner casing or box. apparatus. 11. Device according to at least one of claims 6 to 10, characterized in that the bayonet pin provided in the plug (9) is wirelessly connected to the circuit board. 12. Device according to at least one of claims 6 to 11, characterized in that the sealed casing is provided with a holding element (2a) for mounting in a motor vehicle, in particular for different mounting positions. .