DE102005028995A1 - Method for driving dynamics control and vehicle dynamics control for motorized single-track vehicles - Google Patents

Abstract

The invention relates to a method for driving dynamics control for motorized single-track vehicles, which evaluates camera image sequences with regard to the bank angle p and / or the pitch angle of the vehicle to the road. Control thresholds of an electrohydraulic or electromechanical brake control device are adapted depending on the recognized inclination angle p and / or the pitch angle. Furthermore, the invention relates to a driving dynamics controller for motorized single-track vehicles, with an electrohydraulic or electromechanical brake control unit with control electronics and memory for driving dynamics control program, with a camera in the direction of travel and an image sequence evaluation device, the driving 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 bank angle and a hazard calculator (80) for calculating control thresholds.

Description

The 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 controller for motorized single-track vehicles according to claim 18th

The motorcycle has evolved over the last decades from a cheap means of transportation to a recreational vehicle, in which also increasingly the safety of the driver is brought to the fore. Similar to automobiles a few years ago, more and more motorcycles are equipped with anti-lock braking systems (ABS). From the EP 0 548 985 B1 For example, a stall protection device for a motorcycle is known. Furthermore, from the DE 40 00 212 A1 a method for anti-lock braking of a motorcycle and for determining the coefficient of adhesion known.

From the EP 0 550 849 B1 A method is known with which it is recognized by the evaluation of wheel speed patterns, whether in a strongly braked single-track vehicle, the rear wheel tends to take off. 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 control is that the direct effect on the vehicle is not noticeable during the front wheel pressure reduction. 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.

Around Carry out such an assessment of the vehicle behavior can, it is necessary to know the pitch angle of the vehicle. there is not a big one Accuracy or resolution of the absolute pitch angle in space or relative to the roadway required; it is rather important to follow the course of the pitch angle.

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

These The object is achieved by the Method for driving dynamics control according to claim 1 and the vehicle dynamics controller solved according to claim 18.

By the picture sequence recorded with a camera can be fixed in space standing objects (houses, trees, Road signs, also the roadway horizon) oblique and the pitch angle of the vehicle equipped with the camera can be estimated.

The here present application assumes that a driving dynamics controller for single-track vehicles (Motorcycles, Scooter etc.) this angle information provided become. The process of forming the information from the image sequence is therefore not the subject of this application.

Farther is used as the basis for the vehicle dynamics control assumed that an evaluation algorithm exists, which can recognize from the recorded camera images, whether the vehicle is moving on a dry or wet road surface. The process of forming the lane information from the image sequence is therefore also not the subject of this application.

Additionally will be more information about CAN bus or direct sensor connection as given, such as e.g. the air temperature and / or humidity.

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 (for example, very large banking angle of the vehicle.) High criticality therefore means that, for example, if a vehicle with a large vehicle Slope (close to the physical limit) is moved, a sudden deterioration of the road surface quality (eg, friction coefficient change on the road through wet) with ei very high probability of falling.

The inventive method offers the advantage that through the evaluation of camera image information one in the forward direction Camera mounted strong braking and / or pitching of the camera Vehicle can be detected. This is an early one Trigger a moderate pressure reduction on the front wheel inside and outside an ABS control with recognized critical pitch angle or pitch acceleration, a reduction of engine power via CAN request or similar Access to the engine control unit in the case of a pitch angle course, on a lifting of the front wheel while a strong vehicle acceleration suggests, possible.

A further advantage is, with knowledge 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 after a certain pattern, and when the pitch angle decreases (angular velocity negative or below a defined threshold), the front brake pressure is maintained at the pressure level reached. When replacing the rear wheel (recognizable bar on the estimated angle), the pressure is rebuilt 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.

Farther It is advantageous that by detecting a cornering and involve the soil quality the sleep thresholds for the ABS admission, for example, by very early curtailment alone, by the pressure level or the pressure gradient in the master cylinder, or influenced by a pulsed pressure build-up in the inactive ABS phase can be.

One Another advantage is that when straight brakes on High Friction Lanes an extreme Reibwertausnutzung be performed This is especially for sporty two-wheelers (Sports ABS) advantageous.

Prefers is for the capture of the camera image information used a mono or stereo camera.

Further preferred embodiments the method according to the invention and the vehicle dynamics controller according to the invention go from the subclaims out. The invention will be described below with reference to figures. Hereby shows:

1 a first time sequence of a vehicle dynamics control,

2 a second time sequence of a vehicle dynamics control,

3a a schematic representation of a Einspurfahrzeugs during cornering,

3b a time sequence of a brake control strategy, and

4 a block diagram of a vehicle dynamics controller.

1 shows a first timing of the vehicle dynamics control. signal 1 represents the estimated from the camera image information pitch angle, which constantly with the upper threshold 2 and the lower threshold 3 is compared. signal 5 represents the time derivative of the pitch angle 1 , ie the pitching speed or pitching rate. During braking, in the case of a strong vehicle deceleration, a pitch angle builds up which is clearly above the zero line 4 is because the vehicle on the front suspension and rebounded on the rear suspension. Exceeds the pitch angle 1 the upper threshold 2 (like here at the time 13 ), so 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 8th set from 0 to 1. An additional tax flag 9 is also initially set from 0 to 1 to indicate that in the first phase of the lift-off adjustment, a decrease in the front-wheel brake pressure 11 has to be done. This happens from the time 13 by a step-like pressure reduction modulation. Between the pressure reduction stages is the break time 17 that you usefully adapt to the strength of the recognized withdrawal tendency. At high pitch angle 1 will be the break time 17 short, so that there is a quick reduction of the front wheel brake pressure, while at low and / or returning pitch angle with the help of long pauses only moderate pressure reduction takes place.

At the time 14 reaches the pitch angle 1 its maximum, the pitch rate 5 therefore cuts the zero line 6 , The chosen control strategy does not intend to reduce the pressure from this point onwards. As an additional condition could still be required that the pitch rate with a minimum gradient 7 the zero line intersects, so that it is certain that the decrease of the pitch angle with sufficient Dy Namik happens. Then the control flag 9 reset to 0 and the front brake pressure initially maintained at the level reached.

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

Of the Advantage of the method described here of the adjustment of the rear-wheel lift tendency compared to previously known methods that only have rear wheel speed pattern recognize the loss of ground contact, is that the pitch angle course while the front wheel pressure modulation gives very accurate information about whether the vehicle stabilizes again and the pressure reduction on the front wheel is sufficient, or if due to an even increasing pitch angle a further pressure reduction on the front wheel is necessary.

At the Lifting the front wheel during A strong vehicle acceleration is also the pitch angle used to assess the severity of the situation and one initiate appropriately adjusted compensation.

in principle the starting dynamics of the vehicle is slightly limited to to lower the front wheel again. This can be done via an active braking on the Rear wheel happen when an active pressure build-up by the used Brake hydraulic unit allows is, or by an engine intervention, if a corresponding interface to the engine electronics is present.

by of the electronic brake control unit are usually both types of intervention technically possible, since they are together or alternatively usually used in the so-called traction control or traction control become.

There the engine control the more meaningful procedure in a vehicle with only one drive wheel, here is an example of realization described on the basis of a pure engine intervention. When recognized Front wheel lift is first the engine torque given by the driver reduced in stages. The strenght the reduction depends starting from the severity of the front-wheel lift tendency. When recognized Retrofitting the front wheel, there is a rapid lifting of the engine torque up to the driver's specification, for an optimal average vehicle acceleration to ensure.

In 2 is shown a second timing of a vehicle dynamics control in which the signal 20 again the estimated over the image sequence vehicle pitch angle with the zero line 23 , the signal 24 its time derivative, ie the pitching speed or pitching rate, with the zero line 25 represents. The pitch angle 20 becomes permanently at the (absolute) upper threshold during vehicle acceleration 21 and the lower threshold 22 compared. If the pitch angle exceeds the upper threshold (here at the time 31 ), a lifting of the front wheel is considered recognized and is by setting the control flags 26 and 27 from 0 to 1. From this point on, the engine torque 28 through the setpoint specification 29 reduces and therefore takes a deeper course than the driver's desired moment 30 , The course of the desired value specification 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. After that, with the help of variable break times 34 between the degradation rates the requirement gradually downwards. The break times 34 are then calculated the longer, the lower the lift tendency is. Then falls below the pitch angle 20 again the smaller threshold 22 (as here in the example at the time 32 ), then the control flag 27 reset from 1 to 0 again, indicating that the engine torque now has to be built up again to the driver's request. Upon reaching the driver's request at the time point 33 the entire scheme is reset by resetting the control flag 26 completed.

During the regulation between the times 31 and 33 the control unit gives the reduced engine torque setpoint course 29 in front. This is implemented by the engine control unit by adjusting the throttle and / or by Zündzeitpunktverstellung or cylinder deactivation. The advantages of adjusting the pitch angle compared to methods that are available only wheel speed pattern, as already said in the rear-wheel suspension control, in the fast and safe response and in that braking pressures and engine torque are regulated only to the extent that the respective 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 according to 3a a balance is established between the outward lateral acceleration a _transverse and the gravitational acceleration g. This will be on the road 51 moving vehicle, represented by a longitudinally viewed wheel 50 , from the vertical axis 52 about the skew angle ρ in the skew axis 53 inclined, so that this axis is parallel to the resulting acceleration a _z . This summation acceleration a _z is greater than the gravitational acceleration (1 g) as the resulting vector after the parallelogram set. Thus, one could use one in the vertical axis 52 if the acceleration sensor is close to 1g. 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, the angle of inclination ρ of the vehicle On the basis of camera image sequences, these problems can be identified easily overcome become. The resulting estimated skew angle can additionally via a Secured vertically on the vehicle mounted acceleration sensor become. This is the problem of clear cornering detection detachable with a camera.

driving dynamics are now in the brake control functions special precautions too meet a possible Can prevent fall. Critical is especially the hard braking in curves, the over the Kamm's circle leads to a reduction of cornering forces on the tire. At the Einspurfahrzeug is blocking and / or slipping sideways of the front wheel particularly dangerous. Therefore is provided here, the brake pressure on the front wheel depends on reached slip angle limit.

Various Methods are conceivable, too hard braking by pressure gradient limitation to stop or even the absolute brake pressure, the driver while cornering, to a defined maximum restrict. The goal is in any case, a clear overbraking of the front wheel to avoid. 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 is. Since this is detected quite accurately quantitatively, a very Well adapted brake control strategy for cornering realized become.

A chronological sequence of such a brake control strategy shows 3b , The pressure applied by the driver in the master cylinder 40 is reduced via a modified ABS control strategy depending on the vehicle tilt reduced to the front brake. The signal shows 41 the front brake pressure curve for straight braking (ρ = 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 Blockiernigungen that can be compensated only with relatively large pressure modulation strokes. At higher angles of inclination, the wheel pressure is further reduced (signals 42 and 43 for ρ = 15 ° or ρ ≥ 30 °), from which the wheel speed curves 45 and 46 resulting in smaller delays and lower Radblockierneigungen. 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 can be characterized by a variety of parameter adjustments with control thresholds and the calculation of pressure reduction and pressure increase gradients such a moderate regulation can be achieved. In particular, must the first entry into ABS control during corner braking be made moderately, which is done by a pressure control which already comes into force before the front wheel shows slip enemas. This is perfectly possible especially when the brake controller via pressure sensors in the master cylinder and wheel circle.

Otherwise you could clocked the intake valve of the front-wheel brake circuit clocked during each braking during an extreme cornering, in order to approach the first blocking point with a very limited pressure increase gradient and thus very low excess dynamics. The closing pauses 47 between the valve opening pulses are then chosen the longer, the greater the skew angle.

In 3b includes the pressure curve 43 For the extreme corner braking with more than 30 ° angle no cyclic pressure modulation at all, so that the driver feels no changing moments on the handlebar and can adjust to quasi-stationary conditions. In the 3b shown limitation of the front brake pressure 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 indicates that the roadway is highly likely to be wet and slippery In addition, the parameters of the ABS system during cornering are additionally changed so that even earlier and more moderate control takes place. Then, in addition to the skew angle, this information would be additional parameters for triggering a moderate control.

During the Recognized cornering can not just be the brake pressure on one or the other several wheels can be influenced, but it can also engine interventions take place, which make the cornering safer. If the drive torque is too high, the driving rear wheel may spin and lose its necessary lateral reserve. The vehicle breaks then slightly at the rear. Furthermore, any load change in extreme Cornering to instability lead the vehicle. Therefore, another part of the invention, the engine torque at very large Vehicle tilt - again depending on Bank angle to limit to a defined maximum and in case of abrupt deceleration one Motor Schleppmomenten control to do something for a short follow-up time Requires more torque as the driver pretends to ramp up with the moment variable gradient is degraded.

The Detection of Radabhebevorgängen and Bends in the border area can be combined with the proposed Control strategies, the active intervention in the control equipment of the vehicle, in many cases accidents avoid. However, if the limit of driving dynamics is exceeded, are accidents often unavoidable. With the proposed camera surveillance can also such situations, such as a vehicle rollover or a sideways slipping can be clearly recognized. In such Sees cases the invention that, due to the evaluation of the camera image sequences passive safety systems, such as airbags and / or one by the driver worn air cushion jacket can be activated.

4 shows a block diagram of a vehicle dynamics controller, as an extension to a standard ABS-TCS controller 60 you can see. The standard controller processes input signals 61 , make it into a block 64 Estimates, such as the vehicle reference speed, and other model variables relevant to the control. An essential part of the ABS is the block 65 to calculate control thresholds and to specify an appropriate pressure modulation. The output will be corresponding control signals 62 led to a hydraulic or electromechanical brake. The block 66 is the essential component of a TCS system and calculates nominal engine torque as signals 63 be routed via bus systems or direct signal lines to a motor control device.

This default system will now be around the blocks 72 . 73 and 80 extended. The blocks 72 and 73 appreciate 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 give the signals over the paths 75 and 76 to the danger calculator 80 further. Additionally the danger calculator receives 80 additional Information 71 about humidity, temperature etc.

by directly reading sensors or bus messages from other control units. 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 determines 80 Thresholds and compares these with those in the blocks 72 and 73 estimated angle signals. If pitching and cornering is detected, control signals are generated 81 sent to the standard controller, which then modifies the calculation of ABS control thresholds and the pressure modulation. At the same time, the actuating signals sent to the TCS cause 82 a modified calculation of motor setpoint 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 flashovers and sliding sideways or rolling over, the hazard computer solves the signals 83 Passive safety systems, such as airbags or air cushion jacket.

Claims (20)

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, characterized by the steps: - Evaluating recorded camera image sequences in With regard to the angle of inclination ρ and / or the pitch angle of the vehicle to the roadway, - forwarding the information about the banking angle ρ and / or the pitch angle of the vehicle to the driving dynamics control program, - adapting control thresholds (eg 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 ρ and / or the detected pitch angle. Method according to claim 1, characterized in that that dependent from the detected skew angle ρ and / or the detected pitch angle other adjusting devices via a Signal, in particular over a data bus signal (eg, CAN bus) are controlled. Method according to claim 1, characterized in that that the esteemed Nick angle, the temporal pitch angle course as well as the pitch angle gradient (pitch acceleration) of the Vehicle for detecting a Hinterradabhebens or a Hinterradabhebetendenz while a heavy braking of the vehicle can be used. Method according to claim 3, characterized that when detected rear wheel lift or rear wheel suspension tendency the brake pressure at the front wheel is reduced, and then at the Rear wheel increased becomes. Method according to claim 4, characterized in that that the brake pressure at the front wheel after decrease of the Hinterradabhebens or the Hinterradabhebetendenz after a certain profile on the Time is rebuilt. Method according to claim 1, characterized in that that the esteemed Nick angle, the temporal pitch angle course as well as the pitch angle gradient (pitch acceleration) of the vehicle for detecting a Vorderradabhebens or a Vorderradabhebetendenz while a strong vehicle acceleration can be used. Method according to Claim 6, characterized that when detecting the Vorderradabhebens or Vorderradabhebetendenz lowered the engine power and / or the engine torque of the vehicle be made by the driving dynamics control program corresponding requirements to the engine control unit via CAN or other bus media is sending. Method according to claims 6 and 7, characterized that after decline the Vorderradabhebens or Vorderradabhebetendenz the engine power and / or the engine torque of the vehicle back to an optimal Profile can be built up to the maximum driver requirement by the Vehicle dynamics control program corresponding requirements to the engine control unit via CAN or other bus media is sending. Method according to claim 1, characterized in that that the skew angle ρ, the time course of the skew angle and the gradient of the skew angle (Rolling rate) of the vehicle used to make a statement about the criticality to make a turn. Method according to claim 9, characterized that in extreme cornering (high criticality) a diverse dynamic Parameter adaptation depending on cornering is performed by the ABS control. Method according to claim 10, characterized in that that in extreme cornering (high criticality) all the control thresholds for a first entry into the ABS scheme be lowered by an adaptive amount, the amount in percentage or can be calculated absolutely and, in principle, the greater The higher the criticality the cornering is, being in case of an extreme skew angle by the ABS control already on reaching a certain angle-dependent front wheel brake pressure a pressure stop is initiated. Method according to at least one of claims 9 to 11, characterized in that at extreme cornering (high criticality) all rule thresholds for To switch to a pressure maintenance or pressure reduction phase in the ABS control can be lowered by an adaptive amount, with the amount percentage or absolute can be calculated and, in principle, to gets bigger, The higher the criticality the cornering is. Method according to at least one of claims 9 to 12, characterized in that at extreme cornering (high criticality) the gradient of pressure build-up in an ongoing ABS pressure build-up phase chosen in principle the lower becomes, the higher the criticality the cornering is. Method according to at least one of the preceding claims, characterized characterized in that by evaluation of the camera image information and / or by evaluating other sensors and / or by evaluating Data of other control units more data about the road condition available stand, and that especially on wet roads, high humidity and / or low temperatures all ABS parameters dynamically adjusted be that in the case of corner braking the front wheel pressure level principle further lowered and the cyclic modulation strokes of the ABS control be further minimized. A method according to claim 9, characterized in that in extreme cornering (high criticality) the driver's desired engine torque is limited to a maximum value, which is calculated depending on the banking angle ρ, with increasing skew angle, the maximum allowed male engine torque is smaller. Method according to claim 9, characterized that in extreme cornering (high criticality) abruptly reduced by the driver Engine torque over a ramp function is only slowly degraded by engine drag torque generated instabilities to avoid, the ramp function being chosen to be flatter, the larger the skew angle is. Method according to claim 1, characterized in that that information about Nodding, rolling and in extreme cases slipping and rollover over existing Bus systems (eg CAN) or radio to other passive safety systems be routed in the motorcycle or a driver jacket, so that especially in the case of an unavoidable sideways slipping or rollover the information is used, airbags on the vehicle and / or to activate a driver-worn air cushion jacket. Vehicle dynamics control for motorized single-track vehicles, with an electro-hydraulic or electromechanical brake control device with control electronics and memory for vehicle 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 ) a first block ( 72 ) for estimating the pitch angle and the pitching speed, a second block ( 73 ) for estimating the skew angle and a hazard calculator ( 80 ) for calculating control thresholds. Driving dynamics controller according to claim 18, characterized net that the vehicle dynamics controller with other sensors and / or control units in the vehicle communicates. Driving dynamics controller according to claim 18 or 19, characterized in that the danger computer ( 80 ) depending on the information about pitching, rolling and in extreme cases slipping and rollover more passive safety systems on motorcycle or driver jacket directly or activated via existing bus systems or over the air.