DE4215744A1 - Limiting or controlling of parts moved by external force, esp. for collision protection of window winder, sliding roof, door or tailboard of vehicle - sensing surface acoustic surface waves produced by piezoceramic actuator transmitted over vehicle body part. - Google Patents

Abstract

The arrangement contains at least one electrical-mechanical piezoceramic convertor as an actuator, at least one mechanical-electrical piezoceramic convertor as a sensor (5) and an electronic controller which controls the actuator, evaluates the sensor signals and operates a drive unit accordingly. The actuator and sensor are arranged on a continuous transfer path (3) forming part of a surface region of the actuated part (1) and/or a fixed part with which it interacts so that part of the energy developed by the actuator is converted into acoustic surface waves. The waves propagate on the transfer path and are received by the sensor. USE/ADVANTAGE - E.g. for preventing powered vehicle window and sliding roof collisions. Triggering force is reduced and only reacts in immediate danger area. Is insensitive to fouling, water, wear and ageing of its parts.

Description

The invention relates to a device for limiting or controlling or Regulation of the movement of power-operated parts of a vehicle body according to the preamble of the first claim. Particularly advantageous is their use as collision protection for window regulators, sunroofs, Doors or flaps.

Devices for controlling and in particular for monitoring the closing process motor-operated parts such as doors, flaps or window panes of motor vehicles, are known and use a wide variety of them technical principles. A distinction is made between those that address one direct physical contact, and non-contact working Systems.

In DE-OS 22 46 337 is a safety device for motor-lockable Reveals openings that are a determinant of a acoustic source, e.g. B. the sound intensity, the acoustic  Receiver over a transmission line that conducts airborne sound with the acoustic source is connected. The transmission path can be elastic hose arranged in the area of a closing edge. With his Deformation caused by an obstacle reduces the receiver reaching sound intensity. An evaluation device reacts to this a command to the motor.

The disadvantage of this safety device is the risk of damage or destruction of the transmission link when used as Pinch protection for window regulators of a motor vehicle. In addition, the Fastening the hose on the circumferential edge of the disc to fastening problems, in the area of right-angled pane edges to transmission problems. Within the management framework there is also the Risk of unintentional triggering of the safety device.

DE-AS 24 32 063 describes a device for monitoring the door closing process in mass transit vehicles using the principle of one Photoelectric barrier. Radiation source and sensor are essentially in one Level arranged in the area of the closing edge. The transmission path within the relatively large-volume elastic cover element is provided by a reflector completed at the opposite end of the closing edge. At Deformation of the cover element dampens the light transmission, which leads to the intended reaction of the device via the sensor.

The disadvantage is that the device described is not or only after more complex Internal mirroring for monitoring curved closing edges can be used, but for the window pane of a motor vehicle would be necessary.

DE-PS 27 19 955 is a non-contact field sensor for detection known to people or objects in front of straight edges, whose antenna capacitors are asymmetrical due to approaching objects Experienced change in capacity and via an evaluation device Control commands.  

Unfortunately, field sensors often do not have a sufficiently limited (narrow) Effective range, so that reactions of objects are also triggered can, which are not directly in the direction of movement of the closing edge. For example could use this safety system as a pinch protection for electric windows in motor vehicles, the approximation of Head or shoulder of a passenger on the disk for a reversing movement the same.

DE-PS 30 34 118 and DE-PS 31 36 746 describe a method for electronic monitoring of the opening and closing process of electrical operated aggregates, taking from the temporal changes of the characteristic Characteristics of the unit and their evaluation in a microcomputer an electrical actuator can be influenced. In one of the Multiple sections of subdivided closing areas is used during the closing process the speed or speed of the unit is continuously determined and compared to a limit. If the limit is exceeded, it is done a short-term reversal of movement and then the shutdown.

This method detects pinching very reliably, however as a result of the partially acting during the movement or braking of the adjustment objects considerable inertia, the system reacts relatively sluggishly. On the jammed objects can therefore exert quite large forces.

The invention has for its object to develop a device

• - Which are also suitable for use as a separate or additional Collision protection is suitable, whereby the triggering force is clear should be reduced and a response of the collision protection only should take place in the immediate danger zone and
• - their functional reliability from external influences such as dirt, water, Ice, wear and aging of the parts, not affected becomes,  
• - That without the use of separate, locally from the power-operated part separately arranged switch
• - Which increases the ease of use, in particular by linking ergonomic and logical operating procedures.

According to the invention, the object is achieved by a device with at least an electrical-mechanical converter as an actuator and at least one mechanical-electrical converter as sensor and an electronic evaluation and control device solved, wherein the actuator and the sensor a common, d. H. coherent acoustic transmission path are arranged, which are part of a powered Partially, e.g. B. a window or a tailgate of a motor vehicle, is and for humans, their hands or lifeless objects is particularly easily accessible or can be brought into contact with them. The actuator generates surface acoustic waves in the transmission path (Rayleigh waves), of which the sensor is at least one characteristic Parameter, e.g. B. the amplitude or frequency is recorded and sent to the evaluation and forwarding control device.

By changing the properties of the transmission link, a Make adaptation of the device according to the invention necessary. The changed ones external conditions may vary depending on the wheel guide and disc position to dampen the signal as a result of damage, Contamination or icing also lead to reflections of the signal. According to the invention, the adjustment is carried out by enlarging and reducing the output power and / or the frequency of the actuator. To minimize the technical effort actuator and sensor are advantageously in a functional unit executed in one piece, with their functions successively in time be carried out. Piezo crystals are suitable for this.

But the use of several actuators and sensors can also make sense be. It enables the aging of the transmission link to be diagnosed or the parts connected to it (e.g.  the guiding or sealing areas of a window pane or a flap a motor vehicle) or a short-term changed state, e.g. B. through ice. The sensitivity of the system can easily increase the new external conditions are adapted. Happily happens this automatically via an electronic unit.

On the transmission path free of undesirable discontinuities can attach one (or possibly several) more defined Discontinuities to increase system sensitivity are an advantage be. The discontinuity changes the spreading characteristics of the Surface waves in a predetermined amount and thus serves as a reference point on the transmission line.

Different types of discontinuities can be used. As abrupt widening or narrowing of the transmission path orthogonal they suddenly change the direction of propagation of the surface wave Degree of absorption or the reflection behavior. Other variants are or kinks, waves or edges in the transmission path. The radius of the Discontinuities are on the order of the wavelength of the first harmonic surface wave and is usually much smaller than this self.

If the transmission path is formed by a glass surface, e.g. B. the circumferential Face of a window pane are suitable for influencing the surface waves notches particularly well. Your shape is to the desired Effects very adaptable. So by their shape and depth the ratio of the reflection component to the absorption component is influenced will. Also creating a diode effect where the surface wave pass the notch in one direction with little damping can, as a result of the surface wave in the other direction a (quasi) total reflection is prevented from reproducing beyond the notch.

For behavior that is indifferent to the direction, symmetrical notch geometries are used, which is roughly the shape of an isosceles triangle  have. Asymmetrical notch geometries, on the other hand, lead to a direction-dependent one inverse ratio of reflection to absorption. Running one Surface wave, for example, on a low (in the flat tip Angle to the plane of the transmission path) in any case a further transmission of the surface wave in original direction. Their amplitude is of course corresponding to that Damping and reflection behavior of the edge reduced.

However, the surface wave hits a wedge surface that is steep and an angle of approximately 90 ° or more with the direction of transmission includes, it comes with sufficient notch depth at the same time Total reflection. In contrast, a surface wave can have the other direction of propagation pass the notch (diode effect).

The use of such notches increases the sensitivity of the Measuring system if part of the transmission path does not reach the monitoring area heard, however, external conditions its transmission properties can noticeably influence. An example of this is the vertical one Sealing or guide area of a motor vehicle window pane called whose absorption properties depending on the position of the Disc, the disc bracing and many environmental influences strong can vary. The possibility of hiding or separate evaluation This area is for safe monitoring of the freely accessible Top edge of the pane is often critical. By Difference formation of the signals of different areas delimited by notches a significant increase in sensitivity is achieved. To their further increase and adjustment of the measuring and evaluation system can between the upper and lower stop positions using a tutorial a calibration run may be provided.

An evaluation of the sealing and guide areas can also be used for control purposes the drive power can be used to keep the kinematics constant to guarantee. The use of two transmitter / receiver units, which are preferably each formed as a one-piece piezoceramic oscillator leads to a redundant device. By comparison the measurement results evaluated independently of one another increase  the reliability of the information. Especially with a symmetrical structure The two measuring systems can also be used in cold operating redundancy work.

An advantageous application of the device according to the invention consists in their use as collision protection for electrically operated window regulators, Sunroofs, doors or flaps. By contact of a colliding Objects with the transmission path change the transmission properties. The sensor and the control device registers and initiates this corresponding control commands. It can be a complete or partial reversal the adjustment movement (for window regulators), but also the persistence in the position reached.

Other applications can be in the control of end and intermediate positions of an adjustment part. It is so z. B. possible the upper and lower Approach end position "soft" or short stroke lowering of the side window controls that make it easier to close doors. In addition, that can Functional principle of the invention eliminates the use of switches because the mere touch of one or more designated areas in the transmission path triggers the desired switching effects.

When using the device according to the invention, the transmission path is suitable for collision protection, such surfaces that can be influenced from the outside, which essentially represent the closing surfaces. Your level runs mostly at an angle to the direction of movement of the power-operated component. Is this component, for example, a window pane of a motor vehicle, so one becomes the circumferential face, which is the outer and inner plane of the disc connects, use as a transfer surface. Can be advantageous Actuator and the sensor or a corresponding functional unit on one the window movement sequence is not directly visible, not directly accessible non-interfering component of the transmission path can be arranged. The lower edge of the pane is ideal for this. Should, however Actuator and / or sensor on the transmission path in the area of the closing surfaces (e.g. upper edge of the pane) are used, so the Energy and signal lines on the edge of the pane in the form of printed Conductor tracks provided.  

The energy is coupled in and out either via conductor tracks or cable or wireless (e.g. inductive) if the required energy density and reliability of the components allow this.

One or more of the following are used for signal evaluation Principles for application: transit time measurement, amplitude modulation, phase and frequency modulation. The needs of the Security (including redundancy) and sensitivity.

The invention is described below using an exemplary embodiment and Figures explained in more detail. It shows

FIG. 1a schematic representation of the apparatus of the invention for a closable opening with a transmitter and a receiver at the ends of the transmission path (in open position),

FIG. 1b as shown in FIG. 1A (in closed position),

Fig. 2 shows a schematic representation of the device according to the invention for a closable opening with a movable part arranged in the transmission path,

Fig. 3a schematic representation of the apparatus of the invention for a closable opening with exclusively at one end of the transmission path arranged sensor and receiver (in open position),

FIG. 3b schematic representation of the apparatus of the invention for a closable opening with a clamped object (in the almost closed position),

FIG. 4a schematic representation of a window pane of a motor vehicle with discs arranged on the lower edge of separate transmitter and receiver and a force acting on the top of the subject,

4b qualitative representation. The course of the amplitude over the path (transmission path) (FIG. 4a)

4c qualitative representation. The course of the amplitude over time (FIG. 4a)

FIG. 5a schematic representation of a window pane of a motor vehicle with slices lower edge of the arranged transmitter / receiver units, each generating surface waves with opposite propagation direction, wherein the upper edge of is contacted by an obstacle,

Fig. 5b qualitative representation of the amplitude of a reflected wave and a leaky surface according to Fig. 5a,

Figure 5c are schematic division of the transmission path according to Fig. 5a. Starting from the first transmitter / receiver unit,

Fig. 5d are schematic division of the transmission path according to FIG. 5a, starting from the second transmitter / receiver unit,

Fig. 6 is a schematic representation of a window pane of a motor vehicle with a arranged at the edge of the pane edge transmitter / receiver unit and two differently shaped notch geometries in the transmission path of the surface wave,

Fig. 7 schematic representation of a window in a guide frame with tools for end position detection by coupling into the transmission path of the surface wave.

The invention takes advantage of the ability of a solid body to induce mechanical Waves along its surface as so-called surface waves a design-related or specially created propagation path forward and under the influence of external influences with damping and / or React reflection of surface waves. Sensors guide them  Measuring pulses to an evaluation unit, where, using an algorithm, the System status is assessed, which in turn is the basis for reactions, Control commands or the like is.

Although the exemplary embodiments largely relate to the use of the Device according to the invention as a pinch protection for an electrical Related to window regulators of a motor vehicle, their subject matter extends also on other controllable or regulable systems for which in an analogous manner Surface waves are used and evaluated and the corresponding suitable transmission paths in the area of closing edges or closing surfaces of moving objects.

Fig. 1 illustrates, in a simplified manner schematically the device of the invention for a closable opening is wearing a transmitter 4 and a receiver 5 at the ends of a fixed transmission path. 3 A movable part 1 is shown at a distance from it. The device is in the open position. An electrical-mechanical converter couples energy to one end of the transmission path 3 , some of which is converted into surface waves and transported to the other end of the transmission path 3 , where the receiver 5 receives the signals. Depending on the material and geometry of the transmission path 3 , a certain signal attenuation occurs. In the closed state (see FIG. 1b), that is when the end position of the movable part 1 is reached , the closing surfaces touch each other over a large area and couple a large part of the vibrational energy. The signal attenuation, which is thereby considerably increased, is registered by the receiver 5 and leads to the detection of the end position in the evaluation unit.

A device of very similar construction is shown in FIG. 2, but with the difference that the transmission path 3 is arranged in the lower region of the movable part 1 . The sensor 4 and the actuator 5 are located at its ends. Although the movable part has not yet reached its end position, the sensor 4 registers a strongly damped signal due to the energy being decoupled by a hand 8 which engages in the transmission path 3 .

Referring to FIGS. 3a and 3b are the transmitter and receiver in the form of a function unit 6 arranged the same end of the transmission path 3 and. The functional unit is made in one piece, in which case it alternately functions as an actuator and a sensor. Piezoceramic components can be used successfully for this. The end of the transmission path 3 is designed such that as much of the energy as possible is absorbed and the sensor can therefore no longer receive any signals. When an object 9 is coupled into the transmission path 3 , for example by being pinched, the wave propagation changes due to reflection at the pinching point. The reflected signal reaches the receiver and is the basis for the detection of the pinched condition.

An application of the invention for an electric window lift of a motor vehicle is shown in the schematic illustration in FIG. 4a. A transmitter 4 and a receiver 5 are arranged separately on the lateral edges of the lower pane edge of the window pane 2 . They are coupled into the transmission path of the window pane provided for the transmission of the surface waves, which is formed by the peripheral pane edge 21 , via a wedge 7 . A preferred direction of wave propagation or wave reception is thereby achieved. The entire width of the transmission path is preferably covered by the transmitter 4 or the receiver 5 . The arrows 22 lying in the vicinity of the disk edge 21 indicate the direction of propagation of the surface waves. In the area of the upper edge of the pane, an object 10 or a body part is symbolically identified in the form of a triangle which is in contact with it and is acoustically coupled to it. The vibration energy decoupled by this object means additional damping and reduces the amplitude of the surface wave and the intensity of the signal 50 received at the receiver 5 . FIG. 4b qualitatively represents the course of the amplitude over the transmission path (disk edge 21 ). The analogous qualitative representation of the course of the amplitude over time is shown in FIG. 4c. Thereafter, when a foreign object is coupled into the transmission path at the receiver 5, a signal 51 with an amplitude that is noticeably reduced compared to the signal 52 is to be expected.

The schematic representation of a window pane 2 of a motor vehicle according to FIG. 5a shows the following differences compared to the variant shown in FIG. 4a: The mechanical-electrical transducers 6 coupled to the edges of the lower pane edge each act as transmitters and receivers. In addition, the acoustic transmission path formed by the peripheral disk edge 21 carries two symmetrical and identical notches 11 , the radii of which are smaller than the wavelength of the first harmonic surface wave, in order to be able to influence the wave propagation. The arrangement of the notches 11 in the transmission path was chosen so that they exactly enclose the freely accessible upper edge of the pane, in the area of which a pinching can take place, and separate it from the parallel guide areas 23, 24 adjoining on both sides. The selected notch geometry causes both reflection and damping effects. With their help, the guide areas 23, 24 of the window pane 2 can not only be hidden, but also their damping properties can be evaluated separately. These, in turn, can be used to control the transmit power of the SAW transmitters in order to have a constant SIN ratio.

The following FIGS. 5b, 5c and 5d represent the amplitude of a surface wave over the path or over time in a simplified manner, but without taking reflection effects on the notches 11 into account. In the foreground are the effects caused by an object due to the pinching between the upper edge of the pane and the door frame.

Said object 10 will in any case cause a damping of the amplitude of the signal 53 ( FIG. 5b) emitted by the first transmitter / receiver unit 61 , which is registered by the second transmitter / receiver unit 62 . This will be the case in particular if e.g. B. the hand of a person is pinched, who due to their relative softness and thus good acoustic coupling can hardly cause a significant proportion of reflection of the surface wave. However, in the event that a relatively hard foreign body is coupled into the transmission path 21 of the freely accessible upper edge of the window pane 2 , an additional reflection signal 54 can be registered by the first transmitter / receiver unit 61 and thus improve the informative value of the device through redundancy .

FIGS. 5c and 5d divide the transmission path to schematically, it being understood for one of the first transmitter / receiver unit 61 and on the other by the second transmitter / receiver unit 62. While a fading out of the guide area 23, 24 first passed through the surface wave is possible solely on the basis of the transit time measurement, the next passing guide area 23 or 24 of this surface wave can only be faded out if the signal reflected at the second notch 11 is evaluated. The same applies to the signals transmitted by the other transmitter / receiver unit. Although the notches 11 lead to a considerable attenuation of the signals, their use can be very advantageous. Finally, the masking out of the guide areas 23, 24 on the right and left of the window pane 2 allows a targeted and largely interference-free amplification of the signals of the control area K, which contributes to a significant improvement in the reliability of the information.

Mean in Figures 5c and 5d.:
S₁-S₂ / E₂-E₁ transit time of the signal from the first transmitter / receiver unit 61 to the second transmitter / receiver unit 62 and back.
S₂-E₁ as above, only in the opposite direction.
S₁-B-E₁ runtime of the signal from the first transmitter / receiver unit to notch 11 at location B and back.
S₂-A-E₂ runtime of the signal from the second transmitter / receiver unit to notch 11 at location A and back.
S₁-∇-E₁ transit time of the signal from the first transmitter / receiver unit to the object 10 , which is coupled into the transmission link 21 , and back.
S₂-∇-E₂ runtime of the signal from the second transmitter / receiver unit to the object 10 and back.
S₂-A-E₁ runtime of the signal from the first transmitter / receiver unit to the notch at location A and back. (This management area is excluded from the assessment of a pinched or collision condition.)
S₂-B-E₂ runtime of the signal from the second transmitter / receiver unit to the notch at location B and back. (This management area is also excluded when evaluating a collision condition.)

The control area K is enclosed by the guide areas 23, 24. It represents the part of the transmission link 21 which is freely accessible. To detect a collision state, it is therefore only necessary to evaluate those signal changes which have their cause within the runtime of the control area K.

6 schematically shows a variant of the invention . A transmitter / receiver unit 6 is only arranged at one of the edges of the lower edge of the pane and is coupled into the transmission path 21 of the surface waves via a wedge-shaped element 7 .

Here, too, two notches 12, 13 enclose the transmission path 21 in the upper region of the edge of the pane. However, their geometries differ and are the reason for a different reflection and attenuation behavior. While the notch 12 closest to the transmitter / receiver unit 6 is constructed symmetrically and, apart from an attenuation and a reflection component, the main transmission component has an effect on the surface wave, the second asymmetrically designed notch 13 causes total reflection of the surface wave. For this purpose, this notch 13 has a steeply standing notch flank, which forms an angle α of preferably 90 ° with the upper pane edge and faces the direction of propagation of the surface wave. For the assessment of the system status, only signals are evaluated which lie in the time interval between the first notch 12 and the second notch 13 , which therefore represent the area of the freely accessible transmission path of the upper edge of the pane. The evaluation unit will return a suddenly changed damping behavior to a pinched state and pass on suitable control commands to the servomotor, which preferably leads to the window pane 2 being reversed. General conclusions on the properties within the guide frame 14, 15 can be achieved by evaluating the area between the transmitter / receiver unit 6 and the first notch 12 . A calibration run between the stop positions enables conclusions to be drawn about the general condition in the sealing area and an optimal adjustment of the sensitivity of the monitoring system. Such an adaptation allows, in particular, the switching off of changed external conditions in the transmission path, which can be caused, for example, by aging of the sealing material due to contamination or icing of the guide areas of the disk or also by material fatigue.

Fig. 7 shows the schematic representation of a window plate 2 in a guide frame 14, 15 with tools 17, 18 to the end position. These aids 17, 18 are mechanically coupled into the transmission path of the surface waves as a function of the disk position and using spring-elastic elements and lead to measurable changes in the signals arriving at the receiver 6 . The coupling of the aids 17, 18 for the detection of the lower stop or the upper stop take place at different locations and are therefore very easy to differentiate in terms of measurement technology. The advantage of the end position detection is, on the one hand, that the lower stop can be approached "softly", which enables a lighter, less robust construction. On the other hand, the uppermost adjustment or closure area (sealing area 16 ) is selected from the rest of the adjustment area, in which it is no longer possible to pinch it, and it is necessary to maintain the adjustment force in order to completely close the window opening.

List of the reference numerals used

1 moving part
2 window panes
3 transmission path
4 transmitters
5 recipients
6 transmitter / receiver unit
61 Transmitter / receiver unit
62 Transmitter / receiver unit
7 wedge
8 hand
9 subject
10 item (animate or inanimate)
11 notch (symmetrical)
12 notch (symmetrical)
13 notch (asymmetrical)
14 lead frame
15 lead frames
16 sealing area
17 tools
18 tools
21 disk edge or transmission path
22 Direction of propagation of surface waves
23 Leadership area
24 leadership area
50 signal
51 signal
52 signal
53 signal
54 reflection signal
A ↑ amplitude
α angle
K control area
A place of a notch
B location of a notch

Claims (13)

1. Device for limiting or controlling or regulating the movement of power-operated parts, in particular parts of a vehicle body, such as a window or a tailgate of a motor vehicle, using at least one electrical-mechanical converter as an actuator and at least one mechanical-electrical converter as a sensor, as well as an electronic device for controlling or regulating the actuator, for evaluating the sensor signals and based thereon for controlling the drive unit, characterized in that the actuator and the sensor on a coherent, uninterrupted transmission path which form part of the closing surface area of the externally operated Part and / or the stationary part cooperating with it is arranged such that part of the energy given off by the actuator is converted into surface acoustic waves (Rayleigh waves) which sic h spread on the transmission path and can be received by the sensor. 2. Device according to claim 1, characterized in that for Adaptation to given or changed external conditions in the transmission link, causes z. B. due to aging, pollution, disc guidance or another, an actuator controlled in terms of amplitude is used becomes. 3. Device according to claim 1, characterized in that the Actuator and sensor are made in one piece in the functional unit, wherein the functional unit, which is preferably designed as a piezo crystal, alternately acts as an actuator and acts as a sensor. 4. The device according to claim 1, characterized in that on several actuators and / or sensors are arranged on the transmission path are.   5. The device according to claim 1 and / or 3, characterized in that the transmission path for the surface waves has at least one point of discontinuity contains the propagation characteristics of the surface waves abruptly changes. 6. Apparatus according to claim 1 and 5, characterized in that the discontinuity as a sudden widening or narrowing orthogonal to the direction of propagation, or as a buckling or buckling, or as a groove, notch, edge or the like in the direction of propagation in Transmission path is formed. 7. The device according to claim 1, 5 and 6, characterized in that that the radius of those in the transmission path of the surface waves Discontinuity much smaller than the wavelength of the first harmonic Surface wave is. 8. The device according to claim 1, characterized by its Use for a limit switch, e.g. B. for the upper and / or lower stop of a window regulator or to control z. B. Short stroke reductions. 9. The device according to claim 1, characterized by its Use as collision protection for windows, sunroofs, doors or Valves. 10. The device according to claim 1 and 9, characterized in that the actuator and the sensor on the not directly visible and accessible Transfer surface of the window pane arranged and part a pinch protection for electric windows. 11. The device according to claim 1 and 10, characterized in that the actuator and the sensor are arranged on the closing surface of the window pane and that their supply is printed on the window pane Conductor tracks are made.   12. Method for operating a device for limitation or Controlling the movement of power-operated parts of a vehicle body, characterized in that the information acquisition using the principles of time-of-flight measurement, amplitude modulation, the Phase modulation and / or frequency modulation takes place. 13. The method according to claim 12, characterized in that the Evaluation of reflection and transmission of surface waves in parallel he follows.