DE2215576A1 - PROCEDURES AND EQUIPMENT FOR MEASURING, REGULATING AND / OR DISPLAYING THE MOVEMENT OF LAND VEHICLES - Google Patents

Description

Methods and devices for measuring, regulating and / or displaying the movement of land vehicles The invention relates to methods and devices for measuring, regulating and / or displaying the movement of land vehicles opposite preferably unmarked environment.

Such methods and devices are already known per se. Included a distinction must be made between procedures that relate to anti-lock protection, those that are undesirable due to an intervention in the control system compensate, as well as those that provide information about the behavior of other road users and in dangerous situations automatically in the control, braking or drive system intervention.

This is the maximum available frictional force when braking a vehicle is exceeded between the running link (e.g. wheel or chain) and the road, so lose this their adhesion to the road surface. The static friction goes into the smaller one Sliding friction over, the running elements come to a standstill in the worst case, so that the vehicle slides over the road surface. This not only makes the achievable Brake deceleration reduced, but also the available cornering force, like that that the vehicle is practically no longer steerable and skids. the The risk of blocking the running links is particularly great when the coefficient of friction between the running links and the road surface is small, such as greasy Road or black ice.

If a vehicle is braked, it is due to the deformation the Running links always have a certain amount of slippage, i.e.

the peripheral speed of the running links is always when braking less than the vehicle speed. The greatest liability on the road will be as is well known, depending on the nature of the running link and the road in the case of slip values between 10% and 30% achieved. In the case of complete blocking, however, is the slip 100%. The cornering force increases steadily with increasing slip Zero, is still sufficient with the mentioned slip values between 10% and 30% high. This results in the task of an anti-lock device, independent of the pedal force exerted by the driver increases the braking forces in the vehicle regulate that the optimum slip is always set. Achieved the best results one when all running elements are regulated independently of each other.

According to the state of the art, the actual driving speed is and thus the slip directly only with great effort, i.e. with the help of an unbraked to measure the revolving fifth wheel or a gyro platform. That's why you pull as a criterion for the beginning of the blocking, the strong one that occurs in this case Angular deceleration of the wheel.

This delay is due to the transition to blocking the braking force is no longer applied to the large mass of the vehicle, but only to the much smaller mass of the wheel acts. Conversely, the wheel is very subject to one strong angular acceleration when suddenly releasing the brake again in such a known anti-lock device an inductive pickup is provided as a speed sensor on each wheel.

The disadvantage of this method is that the information about the Vehicle movement can only be obtained indirectly via acceleration measurements. the Deriving the vehicle speed is inevitably imprecise, because disruptive parameters such as tire pressure, tire profile, vehicle load and the like. are included as errors in the measurement. One therefore only achieves an oscillation the braking force around the optimal slip that is desired per se.

On the other hand, it is a very important measure to increase road safety the measurement of the distance to the vehicle in front and generation of warning and Control signals when the speed of your own vehicle is undershot related safety distance. Known systems that are mounted on the street without Aids get by have fundamental disadvantages: Because of the straight-line spread of the beams (IR, radar, laser) in question for distance measurement is one Distance measurement on curves and crests cannot be carried out. There is also the risk of that oncoming traffic, trees, roadsides, bridges and the like. Falsify the measurement. As a remedy is only known road and foreign vehicles with special elaborate Auxiliary devices to be provided object of the present invention is therefore to Specify procedures and facilities of the type mentioned above, which are carried out by direct Contactless speed and / or distance measurement compared to unmarked Environment avoid the detrimental uncertainties of known procedures and which can be implemented in a particularly simple and economical manner.

According to the invention, this object is achieved in that the movement at least one image structure of the environment relative to the vehicle by means of a grid structure an optical correlator system and a downstream photoelectric Receiver in motion converted to proportional electrical push-pull signals will that then these signals in a manner known per se from theirs Common mode components or

Interfering signals are freed and that the signals are then optionally together with signals obtained from other measured quantities - one the movement of the Vehicle influencing servo and / or display system supplied as input signals will.

It is characteristic of further embodiments of the method that the optical correlator system for detecting the slippage of the running elements of a vehicle converts the movement over the ground into speed-proportional signals that this Signalc with the movement of the running members driving and / or braking the vehicle proportional signals are compared and that input signals from this comparison for a servo system, which drives or brakes for the purpose of Reaching a certain target value of the slip between the running link and the ground influenced.

For recording the undefined side output with the correct sign the optical correlator system sets the movement across the ground across the desired Direction of travel into electrical signals proportional to the lateral movement, whereby these Signals either when tracking the measuring direction of the correlator system transversely to Obtaining the setpoint of the direction of travel directly or by deriving it from the difference in direction between the measuring direction and the target direction can be determined arithmetically.

These signals become a servo system that influences the direction of travel fed.

For adapting the brakes and drive to changing driving conditions when cornering, the lateral downforce is achieved by means of the optical correlator system in correct sign proportional to the movement across the ground transversely to the desired direction of travel Signals are converted and these signals are converted into Combination with signals, the preferably the vehicle speed, the slip in the direction of travel and are proportional to the steering lock angle, a drive or braking system and / or the steering-influencing servo system. Furthermore, these Signals for the ongoing display of the difference between the maximum possible and actual Cornering speed used for the purpose of measuring the distance between the vehicle and an obstacle in the direction of travel is provided with at least one optical Correlator system detects an image structure of the obstacle and signals are transmitted Distance, via the relative speed in the direction of travel and via the relative speed Across the direction of travel between the vehicle and the obstacle obtained after the comparison the speed of your own vehicle over the ground of the own vehicle influencing servo system and X or a display and / or warning device are supplied.

To record the approach speed of following vehicles, is by means of a rearward-facing optical correlator system at least a structure of the following vehicle is evaluated, and it is its approach speed and distance generates proportional electrical signals after a comparison with the speed of the own vehicle of a display and / or warning device are fed.

Embodiments of devices for the implementation of the above The methods described are shown schematically in the drawings and below described. 1 shows a device for measuring and evaluating the slip in the direction of travel, FIG. 2 is a functional diagram of the device according to FIG. Fig. 3 shows an example of an arrangement of the optical correlator system, FIG. 4 shows a control device for eliminating undesired changes in the direction of travel, FIG. 5 shows a device to adapt the effects of brakes and drive to changing driving conditions when cornering, Fig. 6 sketches to explain an anti-collision device, 7 shows the functional diagram of a device with optical correlator systems for Avoidance of collisions with obstacles in the direction of travel.

In Figure 1 is a downward optical velocity correlator system 1 shows the driving speed regardless of its distance from the ground Measures contactlessly in the forward direction over the ground. On the four wheels of the depicted Each vehicle is fitted with a speed sensor 2, 3, 4, 5, their output signals together with the output signals of the correlator system 1 the inputs of a comparison stage 6 are fed. This in turn controls one located in the same housing Servo system 6a, which is installed on four brake control valves assigned to the four braked wheels 7, 8, 9, 10 works. These valves are in a known manner in the with the master cylinder 11 connected line 12 of the brake hydraulics. The servo system 6a also works on the differential gear 13 of the drive wheels.

The device described so far has the following function: Exceeds the braking pressure upon actuation of the brake 14 varies a predetermined threshold value the brake servo system via the brake control valves 7, 8, 9, 10 the brake pressure each Wheel until the comparison level 6 is in each case as difference the output signals of the wheel sensors 2, 3, 4, 5 and the correlator system 1 preferably one adjustable setpoint of the slip between wheel and road registered.

The servo system contributes independently of this braking force control Exceeding a predetermined speed difference between the two drive wheels via the Differential gear 13 the driving force on the slower drive wheel O What has been described so far is shown in Fig. 2 as a functional diagram.

3 shows a special embodiment of the speed correlator system 1. At the upper end of a tubular housing 16 are side by side an optical Correlator 17 and a lighting device 18 are arranged. Both are against that longer lower end of the housing tube 16 completed by optics 15 and 19. Above a supply line 20, the tube 16 is fed with optionally heated compressed air, so that the attached below, under the action of a counterweight 21 is Protective flap 22 is opened by the air flow and releases the measuring beam path. The airflow or air from the motor fan, etc. can be used as compressed air.

A speed correlator system 1 shown in Fig. 4 is in contrast to the above-mentioned correlator system 1 so arranged and designed, that it has the correct sign on a driving speed component directed transversely to the direction of travel appeals to. The output signals of the correlator system 1 are together with the signals an angle sensor 24 operated by the steering wheel 23 is fed to a comparison stage 6t. This comparison level registers a lateral speed component, which does not correspond to the steering wheel lock assigned to the desired direction of travel, a downstream power steering system 6a (automatically so fed that it brings the vehicle in the desired direction of travel.

The correlator system 12 is mounted in such a way that it is controlled by the steering wheel 23 is always tracked to the desired direction of travel, the angle encoder 24 can be saved.

Fig.5 shows a simultaneous two coordinates in the direction of travel and speed correlator system 1 "measuring transversely thereto, its output signals together with the signals from wheel speed sensors 2 ″, 5n and the angle sensor 24 are fed to an arithmetic unit 25. This arithmetic unit 25 is calculated taking into account of the steering angle of the running members of the vehicle derived from the steering servo member 26 the amount resulting from the straight-ahead slip and the lateral downforce. Exceeds this amount is a predetermined limit value, so the computer 25 sends to a servo system 27 corresponding output signals. This servo system controls the shown Fall the motor, the brakes of the running members and the steering servo member 26 so long, until the specified limit value is fallen below again. Even before the servo system comes into operation, a warning device 28 is set in motion. A dated Computer-fed display device can be provided for continuous monitoring.

With the aid of FIGS. 6a-6d, basic aspects are now to be considered the distance measurement can be explained. By means of distance measuring assemblies alone the problems of distance measurement of vehicles cannot be solved, because here the distances to obstacles that are not on a collision course would also be measured (e.g. oncoming vehicles, roadside in curves, etc.). To have to As a result, additional information is derived, both about the approach speed as well as the lateral movement of the obstacle: in the figures 6a and 6c an obstacle is shown that is on a collision course. This is expressed in the image impression that the contours and structures of the The obstacle "grows" symmetrically to the line of sight indicated by the "crosshair".

In Figures 6b and 6d, however, the "guard" is a side Image shift superimposed, the obstacle is E.g.

a vehicle that is currently being overtaken and is therefore no longer on a collision course lies.

The growth of the image structures together with the distance gives the Approach speed, the lateral displacement of the image along with the Distance is the side speed of the obstacle. The relationship between the two Ge speed to each other decides next to the size and distance of the obstacle on the question of whether there is a risk of collision or not.

When cornering, for example, although a certain distance is in view (and thus the direction of travel) the opposite side of the road is an obstacle, but that moves out of sight at a certain lateral speed (Fig. 6e). The approach speed is only one component of the relative movement, and the side speed vs shows the observer that there is no risk of collision consists.

From these considerations one recognizes that in addition to the prayer and their change (approach speed) detects the lateral movement of the image must be, relative to the "optical" corresponding to the direction of travel Axis".

Accordingly, it is necessary to use a line of sight to design an image in an image plane with the lens aligned in the direction of travel, its proportions accordingly the angular velocity via the Wander the field of view. Objects that are exactly in the direction of travel when driving straight ahead and do not make any movement of their own, have no angular movement whatsoever. This means in relation to the image field9 that in the direction of the optical axis there is a point without lateral relative movements exist. The greater the angle of the imaging Rays towards the direction of travel, the greater will be for a given distance and Relative speed the angular speed and thus the speed, with which the pixels move across the image field.

If one halves, as shown in Fig. 6f, the image field of one Objectively designed image by means of a straight line passing through the direction of travel "Point of rest" runs, the image components move to the left at a certain distance x and to the right of this bisector then and only then with the same and opposite directions Speed apart (resp.

together) if there is no sideways movement: For a given distance and approach speed, v or ve increases with x due to the above-described dependency of the angular speed on the angle between the direction of travel and the direction of view. If, for example, an image speedometer measuring in the x-direction were to be attached to the left and right of the bisector at a distance x, the approach speed could be determined from the size and sign of the pixel displacement speeds measured there by arithmetic averaging (sum signal) and the lateral speed could be determined by calculating the difference.

For energetic reasons, do you want a large image speed meter? insert in the image halves, the dependency of the values on x disturbs, but only so long one in e.g. optical correlators for this purpose linear uses shared spatial frequency filters. If you put a e.g.

sinusoidal non-linear periodic division a so one can get signals of the same type for a certain approach speed over large value ranges of x.

If you halve the image instead of two x halves, you also halve it into two y halves by a second straight line that runs horizontally through the "rest point", then applies analogously the same as already described. In fact, the pixels run radially Resting point away.

As a result, circular arcs are suitable for the task described non-linear divisions similar to a Fresnel zone plate or sections thereof optimal as a spatial frequency filter (Fig. 6g) In land vehicles, generally only a lateral movement, i.e. displacement in one dimension, is in question.

Therefore, two image speed sensors in the image field are sufficient. Naturally it is also possible for other applications to use corresponding sensors for the second Insert coordinate and from four sensor signals also the direction of one Determine transverse movement in four quadrants.

7 shows a structure designed on the basis of the above considerations for a passive anti-collision device shown schematically. As can be seen is a speed correlation system 1 12st measuring according to four quadrants provided, whose output signals assigned to a coordinate direction each have one Summing stage 34 or 34t and a subtracter 35 or 35 'are supplied. The output signals of these stages are fed to a ratio generator 36, lder respectively the sum and the difference of one coordinate direction related signals to each other.

An arithmetic unit 37 is connected downstream of it. The correlator system is a distance measuring system 38 is assigned, the output signals of which are also fed into the Arithmetic unit 37 can be entered. The output signals of the arithmetic unit can, like indicated, are evaluated in different ways.

Once it is possible to use these output signals to create a servo system 39 to feed, which slows down the speed of the own vehicle for so long, until the vehicle's own speed is less than or equal to that of the other vehicle. Acts on the other hand, the appropriate object is an immovable object, so your own vehicle is braked. In addition to such a servo system is provide a display device 40 and / or a warning device 41 by which the emerging danger is clearly presented.

It is advantageous to have the two measuring systems 1 ″, and 38 behind the windshield of the vehicle where they are protected from the elements.

The advantage over the new passive anti-collision device What is known is that obstacles are on a collision course with other obstacles (e.g. roadside) can be clearly distinguished because they are in the measuring system do not generate an asymmetrical signal component.

responsive to photoelectric by using rIR rays Receivers, it is possible to then also receive signals from a vehicle traveling ahead Received when there is no daylight and the reverse lighting for the vehicle in front has failed.

It is advantageous to have two optical correlator systems on the vehicle to provide one of which measures in two coordinate directions and the front end of the Vehicle is assigned, while the other, measuring me across the direction of travel Correlator system is assigned to the rear end of the vehicle. This arrangement is necessary for the early detection of the breaking away of the rear of the vehicle.

Claims (16)

Expectations U Method for measuring, regulating and / or displaying the movement of Land vehicles as opposed to preferably unmarked surroundings, characterized in that that the movement of at least one image structure of the environment relative to the vehicle by means of a xaster structure of an optical correlator system as well as a downstream one photoelectric receiver in motion proportional electrical push-pull signals is converted so that these signals are then converted from their common-mode components in a manner known per se or interfering signals are freed and that the signals all-inclusive - if necessary together with signals obtained from other measurements - one is the movement of the Vehicle influencing servo and / or a display system as input signals are fed. 2. The method according to claim 1, characterized in that for detecting the slip of the running elements of a vehicle against the ground uses the optical correlator system converts the movement over the ground into speed-proportional signals that this Signals with the movement of the running elements driving and / or braking the vehicle proportional signals are compared that from this comparison input signals for a servo system, which drives or brakes for the purpose of Reaching a certain target value of the slip between the running link and the ground influenced. 3. The method according to claim 1, characterized in that for the correct sign The optical correlator system detects the movement of the undesired lateral downforce across the ground transversely to the desired direction of travel in proportion to the transverse movement Converts signals, these signals either when tracking the measuring direction of Correlator system obtained transversely to the nominal value of the direction of travel or by derivation calculated from the difference in direction between the measuring and target direction are, and that these signals a servo system influencing the direction of travel YÆ are fed. 4. The method according to claim 1, characterized in that for adapting of brakes and drive to the changing driving conditions when cornering the Lateral output by means of an optical correlator system for movement over ground Signals with the correct sign and proportional to the desired direction of travel are implemented and that these signals in combination with signals, which are preferably the vehicle speed, proportional to the slip in the direction of travel and the steering angle are, a drive or braking system and / or the steering-influencing servo system are supplied and / or that these signals are used to continuously display the difference can be used between the maximum possible and actual cornering speed. 5. The method according to claim 1, characterized in that for the purpose the distance measurement between the vehicle and one in the direction of travel Obstacle with at least one optical correlator system an image structure of the Obstacle is detected and signals about the distance, about the relative speed in the direction of travel and across the relative speed to the direction of travel between Vehicle and obstacle are obtained after comparing them with the speed of your own vehicle above ground the speed of your own vehicle influencing servo system and / or fed to a display and / or warning device will. 6. The method according to claim 1, characterized in that for the purpose the detection of the approach speed of following vehicles by means of a rearward optical correlator system at least one image structure of the following vehicle detected and its approach speed and the Distance of the following vehicle generates proportional electrical signals after a comparison with the speed of your own vehicle be fed to a display and / or warning device. 7. Device for performing the method according to the claims 1 and 2, characterized in that a) a speed sensor is preferably provided for each running member (2-5) is assigned that b) the chassis a, the relative speed over Ground contactless and independent of the distance between it and the ground optical correlator system (1) is assigned, and that c) in each case the output signals of the speed sensor and the output signals of the correlator system of a comparison stage matched to a preferably adjustable setpoint value of the slip (6) are supplied, the output signals of which - if necessary after passing through a Amplifier - as control signals to a running member in question in its speed of rotation influencing servo system (6a) are supplied. 8. Device according to claim 7, characterized in that the optical Correlator (17) and optionally a lighting device (18) in a tubular Housing (16) are mounted and that this housing down one wickwick while the vehicle is at a standstill, open when the vehicle is moving Has closure (22). 9. Device according to claim 8, d a d u r c h g e k e n n z e i c This means that when the vehicle is moving, there is an excess pressure in the tubular housing (16) generating means are provided. 10. Device for performing the method according to the claims 1 and 3, d u r c h e k e n n n z e i c h n e t that at least one transverse Direction of travel measuring optical correlator system (1.) is provided, the correct sign Output signals are fed to a comparison stage (6th), which if necessary as Comparison value @@ is supplied with a nominal value, and that this comparison stage eia power steering system (6a.) is connected downstream. 11. Device for performing the method according to the claims 1 and 4, that is, that preferably each of the running gliders an inch transmitter (2 ", 5") is assigned and that a both signed transverse as well as an optical correlator system (i ") measuring in the direction of travel is provided, its susgang signals together with the signals from the rotary encoder (2 ", 5 ') to an arithmetic unit (25) are fed into the resulting from the lateral downforce and straight-ahead slip determined and taking into account the steering angle of the running glider of the Vehicle can be compared with a predetermined limit value, and that a when exceeded this limit value on the drive or the brakes of the running elements and / or the Steering of the vehicle acting servo system (27) is provided 12th Device according to claim 11, d u r c h g e k e n n n z e i c h n e t that two Correlator systems are available, one of which in two coordinate directions measuring assigned to the front end of the vehicle un <l (read other across to Direction of travel mesende is assigned to the rear end of the vehicle. 13. Device according to claim 11 or 12, characterized in that that the arithmetic unit (25) is assigned a display and / or warning device (28) is. 14. Device according to claims 1 and 5, d a d u r c h g e -k E n n z e i c h n e t that one aligned in the direction of travel, preferably for Measurement according to two coordinate directions suitable optical correlator system (1st 1 is provided, which utilizes the object perspective and its change win electrical output signals each perpendicular to the line of sight Coordinate direction ciner comparison stage are supplied that this comparison stage a summing stfe (34, 34 '), a difference stfe (35, 35') and / or ratio-forming Stage (36) comprises and that this comparison stage is followed by an arithmetic unit (37) is fed to the additional signals originating from a distance measuring system (38) be, and that at de output of the arithmetic unit (37) a the Fahrgeschwin <ligkei t of the vehicle influencing servo system (39) and / or display (40) and / or Warning system (41) is connected. 15. Device according to claims 1 and 6, characterized in that that an eptic correlator system directed backwards with his line of sight it is provided, its electrical output signals together with the speed of your own vehicle proportional electrical signals a Ververleichseinrichtung are supplied, which is followed by a warning device is 16. Device according to one of claims 7, 102 11, 12 and 14, characterized in that that the correlator system is arranged in the vehicle behind the windshield L. e e r e i t e