EP1893458A1

EP1893458A1 - Method for regulating driving dynamics and driving dynamics regulator for motorised single-track vehicles

Info

Publication number: EP1893458A1
Application number: EP06763682A
Authority: EP
Inventors: Georg Roll; Stefan LÜKE
Original assignee: Continental Teves AG and Co OHG
Current assignee: Continental Teves AG and Co OHG
Priority date: 2005-06-21
Filing date: 2006-06-13
Publication date: 2008-03-05
Also published as: DE102005028995A1; JP2008546586A; WO2006136515A1

Abstract

The invention relates to a method for regulating the driving dynamics of motorised single-track vehicles, said method evaluating camera image sequences in terms of the tilt angle (ρ) and/or the pitch angle of the vehicle in relation to the track. Regulating thresholds of an electrohydraulic or electromechanical brake control appliance are adapted according to the detected tilt angle (ρ) and/or the pitch angle. The invention also relates to a driving dynamics regulator for motorised single-track vehicles, comprising an electrohydraulic or electromechanical brake control appliance provided with an electronic control system and a memory for a driving dynamics regulating program. Said regulator also comprises a camera oriented in the direction of travel, and an image sequence evaluation device. In addition to a standard ABS-TCS regulator (60), the driving dynamics regulator comprises a first block (72) for estimating the pitch angle and the pitch speed, a second block (73) for estimating the tilt angle, and a risk calculator (80) for calculating regulating thresholds.

Description

Method for driving dynamics control and vehicle dynamics control for motorized single-track vehicles

The invention relates to a method for driving dynamics control for motorized single-track vehicles according to the preamble of claim 1 and a vehicle dynamics control for motorized single-track vehicles according to claim 18.

The motorcycle has evolved over the last decades from a cost-effective means of transportation to a recreational vehicle, in which also increasingly the safety of the driver is brought to the fore. Similar to automobiles some years ago, motorcycles are increasingly equipped with anti-lock braking systems (ABS). From EP 0 548 985 B1, for example, an anti-lock device for a motorcycle is known. Furthermore, from DE 40 00 212 Al a method for anti-lock brakes of a motorcycle and for determining the Haftbeiwertes known.

A method is known from EP 0 550 849 B1, with which it is recognized via the evaluation of wheel speed patterns whether the rear wheel tends to lift off in a heavily braked single-track vehicle. When lift is detected, the pressure on the front wheel is reduced to a specific profile until a significant rear wheel reaction indicates that the rear wheel has sufficient ground contact again. The problem with this type of regulation is that during the front wheel pressure reduction, the direct effect on the Vehicle is not recognizable. Only when the rear wheel touches down does the rear wheel speed pattern indicate that the action was properly dosed. In extreme cases, it may still come to the rollover of the vehicle when the pressure reduction is too low or too slow. This results in the demand for the regulation that the pressure reduction must be dosed quite strong in order to cope as possible even extreme rollover tendencies. For many braking situations, however, this pressure reduction is then too strong, and it comes to local under-braking, braking deceleration fluctuations and thus in turn to stimulate dynamic lifting operations. Also, the problem can not be overcome by attaching sensors to the rear suspension, which indicate the rebound travel of the fork. As long as the rear wheel has no ground contact, you would see the maximum rebound. However, it can not be recognized whether the pitch angle of the vehicle is already decreasing or even increasing to the extent that a risk of rollover is given.

In order to be able to carry out such an assessment of the vehicle behavior, it is necessary to know the pitch angle of the vehicle. No great accuracy or resolution of the absolute pitch angle in space or relative to the roadway is required; it is rather important to follow the course of the pitch angle.

The object of the invention is to provide a method for vehicle dynamics control and a driving dynamics controller for motorized single-track vehicles, which make it possible to handle critical situations, such as lifting a front or rear wheel or braking during a turn. to reliably detect and regulate using a camera.

This object is achieved by the method for driving dynamics control according to claim 1 and the driving dynamics controller according to claim 18.

The image sequence recorded with a camera allows the tilt angle and pitch angle of the vehicle equipped with the camera to be estimated on the basis of fixed objects in the room (houses, trees, traffic signs, and also the road horizons).

The present application assumes that a vehicle dynamics controller for single-track vehicles (motorcycles, scooters, etc.) this information is provided. The method for forming the angle information from the image sequence is therefore not the subject of this application.

Furthermore, it is assumed here as a basis for the vehicle dynamics control that an evaluation algorithm exists, which can recognize on the basis of the recorded camera images, whether the vehicle is moving on a dry or wet lane. The method for forming the lane information from the image sequence is therefore likewise not the subject of this application.

In addition to this, further information about CAN bus or direct sensor connection is assumed as given, such as the air temperature and / or humidity. - A -

According to the invention, the term "criticality of a cornering" is to be understood as meaning that the cornering occurs close to the physical limit of the driving dynamics (eg very large banking angle of the vehicle.) A high criticality therefore means that if, for example, a vehicle with a large bank angle (FIG. close to the physical limit), a sudden deterioration of the road quality (eg, friction coefficient change on the road due to wetness) with a very high probability leads to a fall.

The method according to the invention has the advantage that strong braking and / or pitching processes of the vehicle can be detected by the evaluation of camera image information of a camera mounted in the forward direction of the vehicle. This is an early triggering of a moderate pressure reduction at the front wheel inside and outside of an ABS control when detected critical pitch or pitch acceleration, a reduction in engine power via CAN request or similar access to the engine control unit in the case of a pitch angle course, the lifting of the front wheel during a strong vehicle acceleration suggests, possible.

A further advantage is to be aware of an estimated pitch angle and its time derivative (gradient) to activate a very well adapted control strategy for preventing and balancing the rear wheel lift, which in principle proceeds as follows: As the pitch angle increases, the front brake pressure decreases when the pitch angle is reduced (angular velocity negative or below a defined threshold), holding the front wheel Brake pressure initiated at the reached pressure level. When replacing the rear wheel (recognizable by the estimated angle), the pressure is built up again according to a situation-dependent profile. All measures for detecting a lift-off and restart can be supported and confirmed in principle by recognized rear-wheel speed patterns and by the estimated vehicle deceleration.

Furthermore, it is advantageous that by detecting a cornering and inclusion of the soil quality, the slip thresholds for the ABS entry influenced, for example, by very early Abregelung alone, by the pressure level or the pressure gradient in the master cylinder, or by a pulsed pressure build-up in the inactive ABS phase can be.

Another advantage is that extreme straight-line utilization can be carried out during straight-line braking on high-friction road surfaces. This is particularly advantageous for sporty two-wheelers (sports ABS).

Preferably, a mono or stereo camera is used to capture the camera image information.

Further preferred embodiments of the method according to the invention and of the vehicle dynamics controller according to the invention emerge from the subclaims and the following description with reference to FIGS.

Show it: 1 shows a first time sequence of a vehicle dynamics control,

2 shows a second time sequence of a vehicle dynamics control,

3a is a schematic representation of a Einspurfahrzeugs during cornering,

FIG. 3b shows a time sequence of a brake control strategy, and FIG

Fig. 4 is a block diagram of a vehicle dynamics controller.

Fig. 1 shows a first timing of the vehicle dynamics control. Signal 1 represents the pitch angle estimated from the camera image information, which is constantly compared with the upper threshold 2 and the lower threshold 3. Signal 5 represents the time derivative of the pitch angle 1, that is, the pitching speed or pitching rate. During braking, in the case of a strong vehicle deceleration, a pitch angle significantly above the zero line 4 builds up as the vehicle turns on and off at the front suspension the rear suspension springs. Exceeds the pitch angle 1, the upper threshold 2 (as here at time 13), the pitch angle is considered too large and lifting the rear wheel as recognized. To indicate that there is a lift-off situation, the control flag 8 is set from 0 to 1. An additional control flag 9 is also initially set from 0 to 1 to indicate that degradation of the front brake pressure 11 is to occur in the first phase of liftoff control. This will be done from time 13 through a like pressure reduction modulation. Between the pressure reduction stages is the pause time 17, which is advantageously adapted to the strength of the detected Abhebetendenz. At high pitch angle 1, the pause time 17 is selected to be short, resulting in a faster degradation of the front wheel brake pressure, while only a moderate pressure reduction occurs with low and / or receding pitch angle with the help of long pauses.

At time 14, the pitch angle 1 reaches its maximum, the pitch rate 5 therefore intersects the zero line 6. The selected control strategy envisages that the pressure should no longer be reduced after this point in time. As an additional condition, it could also be required that the pitch rate with a minimum gradient 7 crosses the zero line, so that it is certain that the decrease of the pitch angle takes place with sufficient dynamics. Then the control flag 9 is reset to 0 and the front wheel brake pressure initially maintained at the level reached.

At time 15, the pitch angle 1 again falls below the lower threshold value 3 and the lifting of the rear wheel is considered to be regulated. From this point on, the front wheel brake pressure 11 must be brought back as speedily as possible but also carefully to the level 12 specified by the driver. This is done according to FIG. 1 with a stepped pressure build-up modulation. The pressure build-up phase is characterized by the control flag 10, which is now set from 0 to 1. At time 16, the front wheel brake pressure has again reached the driver's request 12, and within a certain time lag no further lift tendency has occurred. The vehicle is then considered stabilized again, and the control is terminated by resetting the control flags 8 and 10.

One advantage of the method described here of adjusting the rear-wheel lift tendency compared with previously known methods, which only detect the loss of ground contact via rear wheel speed patterns, is that the pitch angle curve during the front wheel pressure modulation provides very accurate information about whether the vehicle stabilized again and the pressure reduction on the front wheel is sufficient, or whether due to a still increasing pitch angle, a further pressure reduction on the front wheel is necessary.

When lifting the front wheel during a strong vehicle acceleration, the pitch angle is also used to assess the severity of the situation and to initiate a suitably adjusted compensation.

In principle, the starting dynamics of the vehicle is slightly restricted in order to set down the front wheel again. This can be done via an active braking on the rear wheel, if an active pressure build-up by the used brake hydraulic unit is possible, or by an engine intervention, if a corresponding interface to the engine electronics is present.

On the part of the electronic brake control device usually both types of intervention are technically possible because they are commonly or alternatively commonly used in the so-called. Traction control or traction control.

Since the engine control is the more meaningful mode of engagement in a vehicle with only one drive wheel, here is one Implementation example described on the basis of a pure engine intervention. If front wheel lift is detected, the engine torque specified by the driver is first reduced in stages. The strength of the reduction depends on the severity of the front wheel lift tendency. If the front wheel is recognized as being restarted, the engine torque is rapidly increased up to the driver's specification in order to ensure optimum average vehicle acceleration.

FIG. 2 shows a second time sequence of a vehicle dynamics control in which the signal 20 again represents the vehicle pitch angle with the zero line 23 estimated via the image sequence, the signal 24 its time derivative, ie the pitching speed or pitching rate, with the zero line 25 , The pitch angle 20 is permanently compared to the (magnitude) upper threshold 21 and lower threshold 22 during vehicle acceleration. If the pitch angle exceeds the upper threshold in absolute value (here at time 31), lifting of the front wheel is considered to be recognized and is indicated by setting the control flags 26 and 27 from 0 to 1. From this point on, the engine torque 28 is reduced by the setpoint input 29 and therefore assumes a lower profile than the torque desired by the driver 30. The course of the setpoint input is calculated similarly to known methods of engine traction control. First, a set to an empirical value, which is a certain amount below the currently achieved engine torque. Thereafter, with the help of variable pause times 34 between the degradation pulses, the requirement is calculated stepwise downwards. The pause times 34 are then calculated the longer, the lower the Abhebetendenz is. Then falls below the pitch angle 20 again the amount smaller threshold 22nd (as here in the example at time 32), the control flag 27 is reset from 1 to 0 again, which indicates that the engine torque now has to be built up again to the driver's request. Upon reaching the driver's request for time 33, the entire control is terminated by resetting the control flag 26.

During the regulation between the times 31 and 33, the control unit presets the reduced engine torque desired course 29. This is implemented by the engine control unit by adjusting the throttle and / or by Zündzeitpunktverstellung or cylinder deactivation. The advantages of pitch-angle control over methods that are available only to wheel speed patterns are the rapid and safe response, as already stated in the rear-wheel lift control, and the fact that brake pressures and engine torque are controlled only to the extent that it does the particular situation requires.

When cornering arise for single-track vehicles compared to two-lane vehicles some additional driving dynamics problems. The driver goes with the vehicle in an inclined position with which, according to FIG. 3a, an equilibrium is established between the outward lateral acceleration a _transverse and the gravitational acceleration g. For this purpose, the vehicle traveling on the roadway 51, represented by a wheel 50 viewed in the longitudinal direction, is inclined from the vertical axis 52 by the oblique angle p into the oblique axis 53, so that this axis lies parallel to the resulting acceleration a _z . This summation acceleration a _z is greater than the gravitational acceleration (Ig) as the resulting vector after the parallelogram set. Thus, one could by reference to a vertical axis 52 when the values are above Ig. However, this results in an ambiguity when troughs and mountain tops with high dynamics are passed through or over. Even then, the display of the acceleration sensor varies widely, so that these cases can not be safely distinguished from cornering.

With the concept presented here of determining the banking angle p of the vehicle on the basis of camera image sequences, these problems can be easily overcome. The resulting estimated skew angle can additionally be secured by a vertical acceleration sensor attached to the vehicle. This solves the problem of unique cornering detection with a camera.

Driving dynamics are now in the brake control functions to take special precautions that can prevent a possible fall. Particularly critical is the hard braking in bends, which leads over the Kamm circle to a reduction of cornering forces on the tires. When Einspurfahrzeug the blocking and / or lateral slipping of the front wheel is particularly dangerous. Therefore, it is provided here to limit the brake pressure on the front wheel depending on the achieved skew angle.

Various methods are conceivable to prevent too hard braking by limiting the pressure gradient or to limit the absolute brake pressure which the driver can apply during cornering to a defined maximum. The goal is in any case, to avoid a clear overbraking of the front wheel. The front wheel Pressure and the front wheel pressure gradient are all the more limited, the more extreme the respective cornering or the greater the angle of inclination reached. Since this is detected quite accurately quantitatively, a very well adapted brake control strategy for cornering can be realized.

A time sequence of such a brake control strategy is shown in FIG. 3b. The pressure 40 applied by the driver in the master brake cylinder is reduced to the front brake via a modified ABS control strategy as a function of the vehicle lean angle. In this case, the signal 41 shows the front wheel brake pressure curve for a straightforward braking (p = 0 °), from which the front wheel speed curve 44 results. In this case, the wheel is cyclically brought to its blocking limit and shows the typical mitkopplungsbedingten blocking inclinations that can be compensated only with relatively large pressure modulation strokes. At higher skew angles, the wheel pressure is further reduced (signals 42 and 43 for p = 15 ° and p> 30 °, respectively), resulting in wheel speed curves 45 and 46 with smaller decelerations and lower wheel block inclinations. The further the control is below the wheel lock pressure level, the lower the modulation strokes and the destabilizing effects on the vehicle. Even with slight variations in friction between the tire and the roadway, a sufficiently high lateral force reserve is thus maintained with high reliability.

In a standard ABS controller, this can be achieved by a large number of parameter adjustments at control thresholds and the calculation of pressure reduction and pressure increase gradients moderate regulation. In particular, the first entry into the ABS control during cornering braking must be made moderate, which can be done by a pressure control that already takes effect before the front wheel shows slip entry. This is perfectly possible in particular if the brake controller has pressure sensors in the master cylinder and wheel circuit. Otherwise, you could clocked the inlet valve of the front-wheel brake circuit clocked during each braking during extreme cornering in order to approach the first blocking point with a very limited pressure build-up gradient and thus very low excess dynamics. The closing pauses 47 between the valve opening pulses are then selected the longer the greater the angle of inclination.

In Fig. 3b includes the pressure curve 43 for the extreme curve braking with more than 30 ° obliquely no cyclic pressure modulation more, so that the driver feels no changing moments on the handlebars and can adjust to quasi-stationary conditions. The limitation of the front wheel brake pressure shown in Fig. 3b can now be extended to various situations. For example, if a temperature sensor or a rain sensor or information provided via bus systems from other control and measurement systems indicate that the roadway is highly likely to be wet and slippery, the parameters of the ABS system may be additionally changed during cornering, such that an even earlier one and more moderate regulation. Then, in addition to the skew angle, this information would be additional parameters for triggering a moderate control. During the detected cornering not only the brake pressure on one or more wheels can be influenced, but it can also be engine interventions that make the cornering safer. If the drive torque is too high, the driving rear wheel may spin and lose its necessary lateral force reserve. The vehicle then breaks easily at the rear. Furthermore, any load change during extreme cornering can lead to instability of the vehicle. Therefore, a further part of the invention, the engine torque at very large vehicle tilt - again depending on the skew angle - to limit to a defined maximum and make in the case of abrupt deceleration a motor drag torque control that requires a little more moment for a short follow-up time than the Prescribing the driver by reducing the torque in a variable-gradient ramp.

Detecting wheel lifts and cornering at high speeds, in combination with the proposed control strategies that actively intervene in the vehicle's controls, can in many cases avoid accidents. However, if the limit of driving dynamics is exceeded, accidents are often unavoidable. With the proposed camera surveillance even such situations, such as a vehicle rollover or a sideways slipping, can be clearly identified. In such cases, the invention provides that due to the evaluation of the camera image sequences passive safety systems, such as airbags and / or worn by the driver air cushion jacket, are activated.

FIG. 4 shows a block diagram of a vehicle dynamics controller which is an extension to a standard ABS TCS controller 60 see is. The standard controller processes input signals 61, from which in block 64 it generates estimated variables, such as the vehicle reference speed, and other model variables that are relevant for the control. As an integral part of the ABS, block 65 is used to calculate control thresholds and to provide adequate pressure modulation. As an output, corresponding drive signals 62 are fed to a hydraulic or electromechanical brake. The block 66 is the essential part of a TCS system and calculates desired motor torques, which are fed as signals 63 via bus systems or direct signal lines to a motor control device.

This standard system is now extended by blocks 72, 73 and 80. The blocks 72 and 73 estimate from the camera image sequences (signal line 70) the pitch angle and the pitch rate as well as the banking angle of the vehicle and pass the signals to the hazard calculator 80 via the paths 75 and 76. In addition, the hazard calculator 80 receives further information 71 about humidity, temperature, etc. by directly reading in sensors or bus messages from other control devices. Furthermore, the hazard calculator also receives data 67 from the standard controller, such as the vehicle speed and acceleration data in the longitudinal and vertical directions, as well as simple vehicle parameters. From the information 67, 71, 75 and 76, the hazard calculator 80 determines control thresholds and compares them with the angle signals estimated in blocks 72 and 73. When pitching and cornering are detected, control signals 81 are sent to the standard controller, which then modifies the calculation of ABS control thresholds and the pressure modulation. At the same time, the control signals 82 sent to the TCS cause a modified one Calculation of motor set torques. Here are u. U. also coordinates requirements of the TCS with those of the hazard computer, in the simplest case by minimization of the maximum torque in the event of engine torque reduction and by maximum formation of the minimum torque in the event of an engine torque increase (drag torque control).

In the event of unavoidable rollovers and sliding sideways or overrun, the hazard calculator triggers the signals 83 passive safety systems, such as airbags or air-cushion jackets.

Claims

Claims:

A method for vehicle dynamics control for motorized single-track vehicles, wherein the single-track vehicle comprises an electro-hydraulic or electromechanical brake control device with control electronics and at least one memory for a vehicle dynamics control program, a camera in the direction of travel and an image sequence evaluation device, characterized by the steps:

Evaluating recorded camera image sequences with regard to the angle of inclination (p) and / or the pitch angle of the vehicle to the road,

Forwarding the information about the banking angle (p) and / or the pitch angle of the vehicle to the vehicle dynamics control program,

Adapting control thresholds (for example for the brake pressure or for the engine nominal torque), in particular when starting and braking the vehicle, and / or influencing the brake pressure and the engine torque as a function of the detected banking angle (p) and / or the detected pitch angle.

2. The method according to claim 1, characterized in that depending on the detected skew angle (p) and / or the detected pitch angle other adjusting devices via a signal, in particular via a data bus signal (for example CAN bus), are regulated.

3. The method according to claim 1, characterized in that the estimated pitch angle, the temporal pitch angle profile and the pitch angle gradient, in particular also the Pitch acceleration, of the vehicle to detect a rear wheel lift or a Hinterradabhebetendenz be used during a heavy braking of the vehicle.

4. The method according to claim 3, characterized in that when detected Hinterradabheben or recognized Hinterradabhebetendenz the brake pressure at the front wheel is reduced, and then increased at the rear wheel.

5. The method according to claim 4, characterized in that the brake pressure on the front wheel after falling of the rear wheel lift or the Hinterradabhebetendenz is rebuilt after a certain profile over time again.

6. The method according to claim 1, characterized in that the estimated pitch angle, the temporal pitch angle course and the pitch angle gradient, in particular also the pitching acceleration, of the vehicle are used for detecting a Vorderradabhebens or Vorderradabhebetendenz during a strong vehicle acceleration.

7. The method according to claim 6, characterized in that upon detection of Vorderradabhebens or the Vorderradabhebetendenz the engine power and / or the engine torque of the vehicle are lowered by the Fahrdyna- mikregelprogramm sends corresponding requirements to the engine control unit via CAN or other bus media.

8. The method according to claim 6 and 7, characterized in that after the decrease of Vorderradabhebens or Vorderradabhebetendenz the engine power and / or the Mo- tormoment of the vehicle can be built up again to an optimal profile to a maximum of the driver request by the vehicle dynamics control program sends corresponding requirements to the engine control unit via CAN or other bus media.

9. The method according to claim 1, characterized in that the skew angle (p), the time course of the skew angle and the gradient of the skew angle (roll rate) of the vehicle are used to form a statement about the criticality of a cornering.

10.A method according to claim 9, characterized in that at extreme cornering (high criticality) a diverse dynamic parameter adjustment in response to the cornering is performed by the ABS control.

11. The method according to claim 10, characterized in that at extreme cornering (high criticality) all control thresholds for a first entry into the ABS control are lowered by an adaptive amount, the amount can be calculated percentage or absolute and in principle the greater is, the higher the criticality of the cornering, wherein in the case of an extreme skew angle by the ABS control, a pressure stop is already initiated when a certain oblique angle-dependent front brake pressure.

12.A method according to at least one of claims 9 to 11, characterized in that at extreme cornering (High Criticality) all control thresholds for switching to a pressure hold or pressure reduction phase in the ABS control can be lowered by an adaptive amount, the amount can be calculated percentage or absolute and in principle the greater, the higher the criticality of the cornering is.

13.Verfahren according to at least one of claims 9 to 12, characterized in that in extreme cornering (high criticality), the gradient of a pressure build-up in a current ABS pressure build-up phase in principle, the lower the higher the criticality of cornering.

14.A method according to at least one of the preceding claims, characterized in that by evaluating the camera image information and / or by evaluating other sensors and / or by evaluating data from other control devices more data about the road condition are available, and that especially when wet Road surface, high humidity and / or low temperatures, all ABS parameters are dynamically adjusted so that, in the case of cornering braking, the front wheel pressure level is in principle further lowered and the cyclic modulation strokes of the ABS control are further minimized.

15.A method according to claim 9, characterized in that at extreme cornering (high criticality) the driver's desired engine torque is limited to a maximum value, which is calculated depending on the skew angle (p), with increasing skew angle, the maximum permitted engine torque is smaller.

16.A method according to claim 9, characterized in that at extreme cornering (high criticality) an abruptly reduced by the driver engine torque via a ramp function is slowly degraded to avoid instabilities caused by engine drag moments, the ramp function is chosen flat as ever greater the skew angle is.

17.Verfahren according to claim 1, characterized in that the information about pitching, rolling and in extreme cases slipping and rollover on existing bus systems (eg CAN) or radio to further passive safety systems in the motorcycle or a driver jacket are forwarded, so that in particular in the case of unavoidable sideways slipping or rollover the information is used to activate airbags on the vehicle and / or a driver worn air cushion jacket.

18. vehicle dynamics controller for motorized single-track vehicles, with an electro-hydraulic or electro-mechanical brake control unit with control electronics and memory for driving dynamics control program, with a camera in the direction of travel and a picture sequence evaluation device, characterized in that the vehicle dynamics controller in addition to a standard ABS TCS controller ( 60) comprises a first block (72) for estimating the pitch angle and the pitching speed, a second block (73) for estimating the tilt angle and a danger calculator (80) for calculating control thresholds.

19. Driving dynamics controller according to claim 18, characterized in that the vehicle dynamics controller is connected to other sensors and / or control devices in the vehicle.

20. Driving dynamics controller according to claim 18 or 19, characterized in that the danger computer (80) in response to the information about pitching, rolling and in extreme cases slipping and rollover more passive safety systems on motorcycle or jacket directly or via existing bus systems or activated by radio.