DE102019206234A1 - Motion sensors for a vehicle based on an electroactive composite material - Google Patents

Abstract

Method for monitoring the condition of a component (20) of a vehicle and / or an industrial plant, comprising providing a sensor device (10) which is based on an electroactive composite material; Attaching the sensor device (10) to a vehicle and / or industrial plant component (20); Operating the sensor device (10) to generate a sensor signal which is induced by a movement characteristic of the component (20); and evaluating the sensor signal in order to determine and output a state of the component (20) and / or of an object / person in contact with the component (20).

Description

TECHNICAL AREA

The present invention relates to the field of vehicle technology. In particular, the invention relates to a motion sensor system for a vehicle which is based on an electroactive composite material (EAC).

TECHNICAL BACKGROUND

Complex systems such as transmissions are manufactured in modern vehicle technology. Such systems are sometimes exposed to extreme kinematic conditions in their applications in which the vehicle moves at high speeds, is controlled with large steering angles or comes to a standstill with high braking forces. In order to ensure the safety of the vehicle occupants or the goods located in the vehicle, it is desirable to check or continuously monitor the status of such systems.

Various approaches to a solution are known from the prior art which serve to carry out the status check or monitoring in a reliable manner. US 2018 169702 A1 discloses, for example, a vibration sensor using a linear resonant actuator (LRA).

However, the vibration sensor known from the prior art is disadvantageous in many respects. For example, the sensor has to be re-attached to the vehicle or to the vehicle component to be examined for each new measurement. This slows down the examination process and reduces the reproducibility of the measurements. In particular, this makes continuous measurement difficult while the vehicle is moving on roadways. For example, the sensor body must be attached and aligned on the vehicle component to be examined before each new measurement.

In addition, for cost reasons it is not possible, or only possible to a limited extent, using the known sensor technology to continuously examine vehicle components for movement properties during their development and production processes. However, this is desirable in order to permanently ensure the quality of the vehicle components with regard to safety.

The invention is therefore based on the object of carrying out status examinations of a complex system for a vehicle, for example a transmission, in a less complex and at the same time more precise manner.

The object is achieved by a device, a method, a computer program product, a computer-readable storage medium and a data carrier signal according to the independent claims.

The electroactive composite material includes, for example, a ferroelectric material, such as a ferroelectric ceramic. Alternatively or additionally, the electroactive composite material can comprise a polymer material. It is preferably a combined material of a ferroelectric ceramic and a polymer. The composite material thus combines the dielectric and piezoelectric properties of the ferroelectric ceramic on the one hand and the mechanical flexibility and pliability of the polymer on the other.

The electroactive composite material can be fabricated into a sheet shape to form the sensor device. This increases the mechanical flexibility and adaptability of the sensor device. The layered sensor device can be attached or applied / glued onto a surface, for example a gear housing, a gear wheel, a steering wheel, etc., in a simple manner.

After the attachment or application to a vehicle or industrial system component to be examined, the sensor device is operated. A sensor signal, for example a piezoelectric voltage or a piezoelectric current, is induced in the electroactive composite material of the sensor device by a movement characteristic of the vehicle component. The voltage or current strength scales with the strength of the movement characteristics of the vehicle component. The movement characteristics of the vehicle component cause deformation, vibration or acoustic excitation in the electroactive composite material of the sensor device.

The sensor signal is received and evaluated by the monitoring device according to the invention in order to determine a state of the vehicle component or objects / people connected to the vehicle component.

The monitoring device according to the invention can be arranged on the vehicle component to be examined, on the vehicle in general, or alternatively outside the vehicle (for example as part of a central vehicle (component) monitoring device in a parking garage or a production workshop).

In this way, the effort for condition monitoring can be reduced. In particular, the on electroactive composite materials based sensor device for the entire duration of the investigation, preferably during the development and manufacturing phase through the test phase to the deployment phase, can be arranged on the vehicle component. This enables permanent and continuous monitoring of the vehicle (component) condition. The quality of the vehicle components in terms of safety can thus be permanently ensured.

Advantageous refinements and developments are specified in the subclaims.

According to one embodiment, the vehicle component comprises a steering wheel, the movement characteristic including a steering wheel movement.

The pressure forces exerted by the driver's hand on the steering wheel lead to vibration or mechanical stress. These can be measured by means of the sensor device attached to the steering wheel. On the basis of the vibration frequency and / or amplitudes or the strength of the mechanical stresses that can be extracted from the sensor data, a movement pattern of the steering wheel can preferably be inferred by means of the evaluation method according to the invention. More preferably, the state of the driver can be determined with regard to his concentration level and / or physical suitability for driving a car.

According to a further embodiment, the vehicle component comprises a vehicle interior component, for example a seat or a seat belt, the movement characteristic comprising a force level exerted on the vehicle interior component and / or a mechanical tension prevailing in the vehicle interior component.

If a vehicle occupant is in a critical state of health, this can be expressed in certain ways. For example, the vehicle occupant with asthma may cough. Here, the seat belt resting on the body of the vehicle occupant is moved, in particular tightened or pressed, due to the changing posture of the vehicle occupant when coughing. Alternatively, the seat on which the vehicle occupant is sitting can be moved, in particular pressed, on a seat surface or backrest due to the changing posture of the vehicle occupant when coughing. This movement of the vehicle interior components such as the seat belt or seat leads to vibration or mechanical stresses, which can be measured by the sensor device attached to the seat belt. The movement of the seat belt is subject to a certain vibration pattern in the event of a cough or another body situation of the vehicle occupant that is critical to health, which can be used as a basis for evaluating the sensor data. From this, the health-critical body situation of the vehicle occupant can be determined, for example.

According to a further embodiment, the vehicle component comprises a lightweight component, preferably a vehicle axle or a vehicle suspension, the movement characteristic comprising a vibration and / or relating to a material property of the lightweight component or a road surface.

The lightweight components such as the vehicle axle or vehicle suspension can deform to a greater or lesser extent under certain circumstances, for example at high vehicle speed or strong steering angles when turning or strong braking forces. This deformation can trigger a sensor signal, for example a piezoelectric signal, in the electroactive composite material of the sensor device. The sensor signal has a specific signal pattern depending on the strength of the deformation. This signal pattern can be used as a basis for evaluating the sensor data. In this way, a level of deformation can be deduced from the sensor data. Alternatively or additionally, because the deformation is dependent on material properties of the lightweight component such as flexibility or extensibility or natural oscillation frequency, a material property of the lightweight component can be inferred based on the sensor data.

According to a further embodiment, the vehicle component comprises a transmission, the movement characteristic comprising a rotational speed and / or a displacement of a drive element contained in the transmission.

The sensor device can be attached to the drive element or another component of the transmission. The component can, for example, be an actuator, for example a linear actuator for moving a movable element in the transmission, or the movable element itself. The movement, in particular rotational movement or displacement of the vehicle component, is accompanied by a centrifugal force or a longitudinal acceleration, which leads to a deformation of the vehicle component. Due to the surface adhesion between the vehicle component and the sensor device attached to it, a sensor signal, for example a piezoelectric signal, is triggered in the electroactive composite material due to the deformation. This signal can be evaluated in order to infer the movement of the vehicle component, as described above.

According to a further embodiment, the vehicle component comprises a parking lock system, the movement characteristic comprising a displacement of a drive element contained in the parking lock system.

The sensor device can be attached to the drive element or to another component of the parking lock system. The component can, for example, be an actuator, for example a linear actuator for moving the drive element. The movement, in particular rotational movement or displacement of the vehicle component, is accompanied by a centrifugal force or a longitudinal acceleration, which leads to a deformation of the vehicle component. Due to the surface adhesion between the vehicle component and the sensor device attached to it, a sensor signal, for example a piezoelectric signal, is triggered in the electroactive composite material due to the deformation. This signal can be evaluated in order to infer the movement of the vehicle component as described above.

According to a further embodiment, the vehicle component comprises a clutch, in particular a dog clutch, preferably an electrical dog clutch, the movement characteristic relating to a connection state and / or including a drive-side or output-side rotational speed.

The connection state relates to a connection between a first coupling element and a second coupling element of the coupling. The connection state can be open, with the first and second coupling elements being separated from one another. The connection state can be closed, the first and second coupling elements being connected to one another. If the sensor device is arranged at an interface between the first and the second coupling element, both connection states (open and closed) can be determined on the basis of the compressive force acting on the electroactive composite material of the sensor device. In the closed connection state, the compressive force assumes a certain value that is greater than zero. In the open connection state, the compressive force takes on the value zero.

According to a further embodiment, the vehicle component comprises a polymer-based transmission gear, the movement characteristic relating to crack formation, a rotational speed and / or a position of the transmission gear.

The polymer-based transmission gear wheel can have a movement characteristic that deviates from the crack-free state due to the formation of cracks. For example, the cracking can result in eccentric rotational movement of the transmission gear. The cracking may be due to a certain manufacturing defect. If the correlation between the manufacturing error and the deviating movement characteristic is known in advance, this correlation can be used as a basis for evaluating the sensor data. In this way, conclusions can be drawn from the sensor data about the specific manufacturing defect.

In all of the embodiments described above, the evaluation unit can be designed to compare the tension strengths or compressive forces extracted from the sensor data, which prevail on the electroactive composite material in the respective movement characteristics of the vehicle component, with a predefined threshold value. If the threshold value is exceeded, a warning signal is triggered. The warning signal can cause a countermeasure that can be implemented by the vehicle (such as braking, accelerating, stopping, increasing or decreasing the temperature in the vehicle interior and / or the volume of the loudspeaker system in the vehicle ... etc.). As an alternative or in addition, the warning signal can be output to an external entity, such as a monitoring center that monitors the vehicle.

The computer program product according to the invention is designed to be loaded into a memory of a computer and comprises software code sections with which the method steps of the method according to the invention are carried out when the computer program product is running on the computer.

A program belongs to the software of a data processing system, for example an evaluation device or a computer. Software is a collective term for programs and associated data. The complement to software is hardware. Hardware describes the mechanical and electronic alignment of a data processing system. A computer is an evaluation device.

Computer program products generally comprise a sequence of instructions which, when the program is loaded, cause the hardware to carry out a specific method that leads to a specific result. When the program in question is used on a computer, the computer program product produces the inventive technical effect described above.

The computer program product according to the invention is platform independent. That means it can run on any computing platform. The computer program product is preferred executed on an evaluation device according to the invention for detecting the surroundings of the vehicle.

The software code sections are written in any programming language, for example in C, C ++, Python, Java, Matlab or LabView.

The computer-readable storage medium is, for example, an electronic, magnetic, optical or magneto-optical storage medium.

The data carrier signal is a signal which the computer program product from a storage medium on which the computer program product is stored to another entity, for example another storage medium, a server, a cloud system or a data processing facility , transmits.

• 1 eine schematische Darstellung einer Vorrichtung zur Überwachung eines Zustands einer Fahrzeugkomponente gemäß einem Ausführungsbeispiel;
• 2 eine schematische Darstellung einer an einem Zahnradelement angebrachten Sensoreinrichtung zur Anwendung mit der Überwachungsvorrichtung aus 1;
• 3 eine schematische Darstellung einer an einem Getriebesystem angebrachten Sensoreinrichtung zur Anwendung mit der Überwachungsvorrichtung aus 1;
• 4 eine schematische Darstellung einer an einer Klauenkupplung angebrachten Sensoreinrichtung zur Anwendung mit der Überwachungsvorrichtung aus 1; und
• 5 schematische Darstellungen dreier Verbindungszustände der Klauenkupplung aus 4.

Embodiments will now be described by way of example and with reference to the accompanying drawings. Show it:

• 1 a schematic representation of a device for monitoring a state of a vehicle component according to an embodiment;
• 2 a schematic representation of a sensor device attached to a gearwheel element for use with the monitoring device 1 ;
• 3 a schematic representation of a sensor device attached to a transmission system for use with the monitoring device 1 ;
• 4th a schematic representation of a sensor device attached to a claw coupling for use with the monitoring device 1 ; and
• 5 schematic representations of three connection states of the dog clutch 4th .

In the figures, the same reference symbols relate to the same or functionally similar reference parts. The relevant reference parts are identified in the individual figures.

1 shows a schematic representation of a device 10 for monitoring a condition of a vehicle component 20th according to an embodiment. The device 10 includes an input interface 12th for obtaining sensor data which a sensor device 11 when measuring a vehicle component 20th generated. The device 10 includes an evaluation unit 14th to evaluate the received sensor data. The evaluation unit 14th is designed to determine a state of the vehicle component from the sensor data 20th or to determine an object or a person in contact with it. The device also includes 10 an output interface 16 for outputting the determined status to an external entity, such as the vehicle or a database, a server system, a cloud system and / or a blockchain system.

The sensor device 10 is formed from an electroactive composite material and attached to the vehicle component 20th attached or attached. The sensor device 10 can be formed in layers.

2 shows a schematic representation of a gear arrangement 24 attached sensor device 11 for use with the monitoring device 10 out 1 . The sensor device 11 can on a housing of the gear assembly 28 attached. The gear arrangement 24 can when moving the vehicle in which the gear arrangement 24 is installed, a deformation or mechanical tension in the electroactive material of the sensor device 11 cause which an EAC sensor signal, such as a piezoelectric signal, triggers. The sensor signal (sensor data) is from the monitoring device 10 received and evaluated in order to determine the movement pattern of the gear arrangement 24 or close the vehicle.

3A shows a schematic representation of an on a transmission system 22nd attached sensor device 11 for use with the monitoring device 10 out 1 . The sensor device 11 is arranged on a gear housing so that deformations of the surfaces of the gear housing cause deformation of the electroactive composite material. This triggers a sensor signal, for example a piezoelectric signal (sensor data), which is transmitted by the monitoring device 10 is received and evaluated. A specific movement pattern of the transmission system can be derived from this 22nd determine. For example, correlations between the movement patterns and the piezoelectric current / voltage strengths can be used as a basis for the evaluation method.

3B shows a method for attaching the sensor device 10 on a component 28 . The component 28 is on one top (the one in 3B is directed upwards) with an adhesive. The sensor device 11 is attached to a screw 31 attached by the sensor device 11 from below onto one face of the screw 31 is brought into contact. Then the combination of the screw 31 and the sensor device 11 connected with the glue. Alternatively, the Sensor device 11 on the top of the component 28 glued on before the screw 31 with the sensor device 11 is connected at the top. 3C shows the screw 31 and the sensor device 11 in an enlarged view. The screw 31 has a circular recess at the front 312 to accommodate the sensor device 11 on.

4th shows a schematic representation of one on a dog clutch 26th attached sensor device 11 for use with the monitoring device 10 out 1 . The claw coupling 24 is preferably an electrical claw coupling and has a first coupling element 262 and a second coupling element 264 on. The first and second coupling elements 262 , 264 each have several teeth 266 , 268 that are extensively distributed.

Depending on the relative rotational position between the first and the second coupling element 262 , 264 can the claw coupling 26th have a certain connection state. 5 shows schematically three different connection states (I), (II), (III) between the first and second coupling element 262 , 264 the claw coupling 24 out 4th . The two coupling elements are in the first connection state (I) 262 , 264 spaced from each other. This is an open connection state. The two coupling elements are in the second connection state (II) 262 , 264 in contact with each other, with the teeth 266 of the first coupling element 262 and teeth 268 of the second coupling element 264 press each other laterally. It is a medium connection state. The two coupling elements are in the third connection state (III) 262 , 264 interlocked so that the teeth 266 of the first coupling element 262 in gaps between teeth 268 of the second coupling element 264 intervene and vice versa. It is a closed connection state.

The sensor device 11 is like in 4th shown by way of example on a side surface 270 of a tooth 268 of the second coupling element 264 appropriate. Depending on whether the connection state (I), (II) or (III) in the dog clutch 26th prevails, the sensor device 11 either exposed, partially from a side surface 280 of a tooth 268 of the opposite first coupling element 262 acted upon or entirely by an annular surface 290 of the first coupling element 262 applied. The connection states (I), (II), (III) can each be initiated by an operating state of the vehicle (or a component using the dog clutch such as parking lock, brake or clutch). It is therefore possible to infer an operating state of the vehicle / component from the connection states. For this purpose, the compressive force that is characteristic of the respective connection state and that acts on the sensor device 11 acts, can be set in correlation with the respective operating state, wherein this correlation can be used as the basis for the evaluation method of the sensor data.

List of reference symbols

10

Monitoring device

11

Sensor device

12

Input interface

14th

Evaluation unit

16

Output interface

20th

Vehicle component

22nd

transmission

24

Gear arrangement

26th

Claw coupling

262

first coupling element

264

second coupling element

266, 268

teeth

270, 280

Side face

290

Ring surface

28

Component

31

screw

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 2018169702 A1 [0003]

Claims (13)

Method for condition monitoring of a component (20) of a vehicle and / or an industrial plant, comprising: - providing a sensor device (10) which is based on an electroactive composite material; - Attaching the sensor device (10) to a component (20) of a vehicle and / or an industrial plant; - Operating the sensor device (10) to generate a sensor signal which is induced by a movement characteristic of the component (20); and - Evaluation of the sensor signal in order to determine and output a state of the component (20) and / or of an object / person in contact with the component (20). Procedure according to Claim 1 wherein the vehicle component (20) comprises a steering wheel, wherein the movement characteristic comprises steering wheel movement. Procedure according to Claim 1 or 2 wherein the vehicle component (20) comprises a vehicle interior component, for example a seat or a seat belt, wherein the movement characteristic comprises a force level exerted on the vehicle interior component and / or a mechanical tension prevailing in the vehicle interior component. Method according to one of the preceding claims, wherein the vehicle component (20) comprises a lightweight component, preferably a vehicle axle or a vehicle suspension, wherein the movement characteristic comprises a vibration and / or relates to a material property of the lightweight component or a road surface. Method according to one of the preceding claims, wherein the vehicle component (20) comprises a transmission (22), the movement characteristic comprising a rotational speed and / or a displacement of a drive element contained in the transmission (22). Method according to one of the preceding claims, wherein the vehicle component (20) comprises a parking lock system, wherein the movement characteristic comprises a displacement of a drive element contained in the parking lock system. Method according to one of the preceding claims, wherein the vehicle component (20) comprises a clutch, in particular a dog clutch (24), preferably an electric dog clutch, wherein the movement characteristic relates to a connection state of the clutch and / or includes a drive-side or output-side rotation speed of the clutch. The method according to any one of the preceding claims, wherein the vehicle component (20) comprises a polymer-based transmission gear, wherein the movement characteristic comprises cracking, a rotational speed and / or a position of the transmission gear. Method according to one of the preceding claims, wherein the vehicle component (20) comprises a brake. Device (10) for monitoring the condition of a component (20) of a vehicle and / or an industrial plant, comprising: - an input interface (12) for receiving a sensor signal which is induced by a movement characteristic of the component (20), the sensor device (11) being attached to the component (20), - An evaluation unit (14) for evaluating the sensor signal in order to determine a state of the component (20); and - An output interface (16) for outputting the ascertained state of the component (20) and / or of an object / person in contact with the component (20). Computer program product, comprising instructions which, when the program is executed by a computer, cause the computer to perform the method according to Claim 1 execute. Computer-readable storage medium on which the computer program product is based Claim 11 is stored. Data carrier signal that the computer program product according to Claim 11 transmits.

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