DE102006034411A1 - Device for speed and stopping control in motor vehicles - Google Patents

Abstract

A device for speeding and stopping control in motor vehicles, comprising a sensor system (10) for locating a vehicle in front, a slave controller (22) for regulating the distance of the driver's vehicle to the vehicle in front while driving, and a stop controller (24) which controls the vehicle in brakes the stand when it is detected that the fore vehicle is stopping or stopping, characterized in that in the stop controller (24) a roll phase controller (28) is implemented which keeps its speed approximately constant during a roll phase shortly before the standstill of the own vehicle ,

Description

State of the art

The The invention relates to a device for speed and stopping control in motor vehicles, with a sensor system for locating a vehicle in front, a follower to control the distance of the own vehicle to the fore vehicle during the ride, and a stopper, which is the own vehicle in the Stand brakes when it is detected that the fore vehicle is stopping or will stop.

For motor vehicles are known as ACC (Adaptive Cruise Control) systems, which it allow the speed of the vehicle in free-ride on one chosen by the driver To regulate desired speed or, if of the location system, typically a radar sensor, one on its own track immediately locating the vehicle ahead, adjusting the speed so that this Traced the front vehicle at a reasonable safety distance becomes. This safety distance is speed dependent and is usually about the time gap defined between the two vehicles. The scheme on the by the time gap certain desired distance is called a follow-up control.

It are advanced ACC systems in development beyond that also a stop and go Function or at least provide an automatic stop function, so that Vehicle can be braked automatically in the state, if that Forwards vehicle stops. In this case, the stopping process of the own vehicle should be regulated so that the vehicle is in a predetermined stopping distance to the front vehicle to a standstill comes.

With Help of the follower can be the stopping process does not regulate adequately, because if given time gap the speed of the vehicles decreases to 0, too the desired distance to 0 and not as desired to the stopping distance lose weight. Furthermore the stopping process should be controlled so that the deceleration of the vehicle for the vehicle occupants preferably is comfortable, that is, the delay should be as gentle as possible and without jerky changes the (negative) acceleration take place. Thus the automatic Stopping function is accepted by the driver, the deceleration behavior should be while the stopping process also possible largely correspond to the intuitive behavior of a human driver.

In addition to The follow-up controller is therefore provided with a special stopping controller. which is activated when detected on the basis of the data of the sensor system that will The vehicle is already standing, for example when driving onto a jam end, or if based on the delay of the front vehicle is foreseeable that this vehicle stops. One suitable criterion by which it can be seen that the fore vehicle continues, could for example, that the negative acceleration of the front vehicle relative to the roadway falls below a certain threshold and then during a certain period of time constantly below this threshold, or at least below one something higher, but also remains negative second threshold. The Thresholds and the time span should be speed-dependent, as an imminent stop the front of the vehicle so much the more likely will be, the smaller its speed already is.

Of the Anhalteregler can then, for example, work so that he Based on the sensor data tracked speed curve of the front vehicle extrapolated into the future and on this basis the probable Stop point of the vehicle in front calculated. After subtraction of the stopping distance you get then the stopping route for your own vehicle. The stopping controller then calculates a delay profile for the own vehicle, which ensures that your own Vehicle comes to a halt after the calculated stopping distance. Under the Condition that the delay the front vehicle has been extrapolated correctly, the distance between the two stationary vehicles then the predetermined stopping distance correspond.

Of course it will the distance to the front vehicle also during the stopping process continues monitored by the radar sensor, so that, for example in the case that Front vehicle to a full braking passes, still corrective can be intervened and a collision on the front vehicle is prevented. Likewise, it is conceivable that the stopping rule modified when the speed of the front vehicle slows down as first was to be expected. A strict coupling to the delay behavior However, the front of the vehicle has the disadvantage that it u.U. too substantial impairments of comfort and / or the braking system of your own vehicle unnecessary is charged.

In DE 100 47 048 A1 a control concept is described in which during the stopping process, the target deceleration of the own vehicle additively composed of three shares, namely a share with constant delay, a share with distance-dependent, with decreasing distance increasing delay, and a share with one of the vehicle speed dependent delay.

Disclosure of the invention

task The invention is a device of the type mentioned to create, with the stop in a comfortable and brakes-friendly deceleration behavior and a closer adherence to the stopping distance can be achieved can.

These Task is according to the invention with the solved in claim 1 features. In the stop control is implemented a roll phase controller that is short during a roll phase before the standstill of the own vehicle its speed nearly keeps constant.

If a stopping process of the front vehicle is detected, first as usual of Stop control is activated, and the speed curve of your own Vehicle follows first the delay profile calculated by the stop controller. The speed does not decrease to 0 with undiminished rate of change, but shortly before reaching standstill, the scroll phase controller is activated, and the vehicle goes into a roll phase in which the speed curve much flatter or even approximate remains constant until, finally, if the desired Stopping distance is reached, the vehicle finally braked to a standstill becomes.

These solution has the advantage that the Stopping distance even with unexpected movement of the vehicle in front precise can be complied with. Because the speed towards the end of the roll phase already relatively low and largely independent of the prehistory of the stopping process, the vehicle brake control becomes the final braking considerably relieved in the state. In particular, can be achieve that stunt With high comfort and minimal hitching done. At the same time, you can this reduces the load and wear of the vehicle brake become.

advantageous Embodiments and developments of the invention are specified in the subclaims.

Prefers is used in the calculation of the deceleration profile by the stopping controller already a short roll phase with a certain Minimum duration, i.e., the vehicle becomes something at first stronger delayed as it is in a conventional Stop control would be the case so that enough space for the Rolling phase is created without the own vehicle too tight on the front vehicle auffährt.

The Initiation of the final Braking in the state can then depending on the measured distance to the front vehicle, so that the stopping distance adjusted precisely can be. Thus, especially situations can be mastered, in which the front vehicle first decelerates to a low speed or to a standstill, then, however, if the brake is completely or partially released a little further vorrollt. The associated increase or decrease in the Distance to the front vehicle is by a corresponding extension the roll phase balanced. The driver thus needs, after that Vehicle was brought to a halt, not to start again, to close closer to the front vehicle.

Of the Rollphasenregler is preferably on the transmission of the respective Vehicle tuned so that, for example For vehicles with automatic transmission and torque converter the circumstance bill can be worn that too idle still a certain thrust moment is present. For example For example, the roll phase controller may be designed to be at the beginning of the roll phase The vehicle gently decelerates to the speed with which it is due of the idle thrust torque continues to roll. For vehicles with a gearbox, that generates no thrust torque when idling, for example in vehicles with manual transmission, the delay can be at the beginning of the rolling phase be controlled or regulated so that the vehicle to reach of the final Stop point gently rolls out. If necessary, can also Gradient or gradient be charged to the carriageway.

There the device according to the invention ensures that against End of the roll phase, the final one Brakes in the state, largely standardized conditions exist offers the invention the particular advantage that specifically to the respective brake system the vehicle adapted Interfaces can be provided that are comfortable Pressure build-up to final Trigger a stop from the roll phase. When the braking system (and to measure the actual speed used sensors), for example, an acceleration control to allow 0 to reach the speed can be through the Interface a target acceleration are given, then through the braking system is adjusted. With other brake systems can a desired acceleration can be specified, which then from the brake system from a relationship known at low speeds as Target brake pressure can be interpreted. In a further embodiment For example, the interface may issue a stop signal through which the brake system a controlled brake pressure buildup is triggered.

Especially in the cases in which the Rollphasenregler specifically to the transmission and / or braking system adapted to the vehicle is, it proves useful if this roll phase controller is designed as a separate control module. The stopping controller then has at least two modules, namely the a the one conventional Stop control corresponding profile module, which at the beginning of the stopping process the delay profile calculated and then the delay of the vehicle according to this profile, and the other Scroll phase controller activated towards the end of the stopping process. Together with the slave controller, the device then has a total of at least three control modules, the time-shifted, overlapping or can work in parallel. A strategy selection module may be provided, depending on the traffic situation at the right time switching between the different Effect modules. In an output stage of the device, the Output signals of the various control modules selected or combined and then to the actuators, so the drive system and the braking system of the vehicle to be forwarded. For example can the output signals of the various modules in the manner of a weighted Sum added superimposed be, whereby by shifting the weights a smooth cross-fading from one rule module to another.

In a particularly preferred embodiment is the time at which the roll phase is initiated by the deceleration behavior of the fore vehicle. When the speed of the front vehicle slows down more slowly than first assumed in the calculation of the delay profile that can be done by an earlier one initiated and correspondingly longer Roll phase be taken into account.

Brief description of the drawings

One embodiment The invention is illustrated in the drawings and in the following Description closer explained.

It demonstrate:

1 a block diagram of a device according to the invention for speed and stopping control;

2 Diagrams illustrating the operation of the device;

3 a speed / time diagram for typical speed profiles of the front vehicle and the own vehicle with the device according to the invention; and

4 a flowchart for explaining the operation of the device.

Embodiment of the invention

In the 1 The device shown comprises a sensor system 10 in the form of a front mounted in the vehicle radar sensor for locating front vehicles, as well as at least one actuator system 12 for engaging the drive system of the vehicle and an actuator system 14 for the intervention in the brake system. At the heart of the device is an electronic data processing system 16 in which the various control functions are implemented as software modules or possibly also as specialized hardware modules.

An entrance level 18 of the data processing system takes from the sensor system 10 supplied data, in particular the distance and the relative speed of a front vehicle, which was located as an immediately preceding vehicle in the own lane, also other input signals, which include the state of motion of the own vehicle, here represented by a vehicle speed sensor 20 that indicates the speed of your own vehicle.

The data processing system 16 also contains a follower 22 and a stopper 24 , The follower 22 is responsible for regulating the distance to the front vehicle when both vehicles are in motion. Its operation corresponds to that of a conventional ACC system. The stopper 24 is activated when the data from the sensor system 10 shows that the front vehicle stops. Task of the stopping controller 24 It is then to control the stopping process of the own vehicle so that this vehicle comes to a stop at a predetermined stop behind the front vehicle to a halt.

The stopper 24 is in turn divided into two sub-modules, namely a profile module 26 and a roll phase controller 28 , Through a strategy selection module 30 become the profile module 26 and the roll phase controller 28 and the follower 22 activated and deactivated depending on the traffic situation. This is where the strategy selection module comes in 30 as well as the two modules of the Anhaltereglers 24 and the follower 22 on the front door 18 provided data.

The follower 22 , the profile module 26 and the roll phase controller 28 provide output signals, typically in the form of desired accelerations, in an output stage 32 the data processing system selected and / or combined with each other and then to the actuator systems 12 . 14 out are given. As in 1 symbolized by a dashed arrow, determines the strategy selection module 30 which of the three output signals from the output stage 32 is forwarded to the actuator systems or in which way these output signals are combined with each other before their transmission to the actuator systems. In a simple embodiment, the output stage 32 in each case only one of the three output signals is forwarded to the actuator systems, that is, either the desired acceleration, that of the slave controller 22 delivered, or the target acceleration, by one of the two modules of the stopping controller 24 is provided, and the strategy selection module 30 controls the switching between the different control modules. However, it is also possible that the output signals of the various control modules are superimposed in the manner of a weighted sum with each other. Likewise, a combination in the sense of a maximum or minimum selection is conceivable. For example, during a stopping process, that is, during a phase in which the stopping controller 24 is active, the follower 22 monitor whether a certain minimum distance to the front vehicle is maintained, and he can the signals of the stopping controller 24 override to ensure compliance with this minimum distance.

The operation of the device will now be based on 2 be explained in more detail.

2 (A) shows a "normal" ACC situation in which the device according to 1 equipped "own" vehicle 34 behind a front vehicle 36 drives and the distance of the vehicle 34 to the front vehicle 36 through the follower 22 is regulated. The stopper 24 is inactive in this situation.

2 B) illustrates a situation in which the speed of the front vehicle 36 has decreased significantly. The speeds of the vehicles are symbolized by vector arrows. A significant decrease in the speed of the vehicle in front 36 indicates in particular in the cases where the speed of both vehicles is already relatively low anyway, then that the driver of the front vehicle 36 intends to stop. This situation will be determined by the strategy choice module based on appropriate criteria 30 recognized, then the stopper 24 activated while the follower 22 if necessary remains active in the background.

The control is then first of the profile module 26 of the stopping guide 24 accepted. This module uses the data from the sensor system 10 the speed decrease of the fore vehicle 36 and extrapolate this to the future, to calculate the point at which the front vehicle 36 is expected to come to a standstill. This anticipated stopping point of the fore vehicle 36 is in 2 B) With 36 ' designated. Task of the stopping controller 24 It is now the stopping process of your own vehicle 34 to control or regulate so that this vehicle comes to a "reasonable", fixed predetermined stopping distance D _A behind the front vehicle to a halt. The stopping position of the vehicle then reached 34 is in 2 B) With 34 ' designated. The profile module 26 subtracts the stopping distance D _A from the distance between the current position of the own vehicle 34 and the expected stop position 36 ' of the fore vehicle and thus calculates the stopping distance W within which the own vehicle 34 must be brought to a standstill. Based on this stopping distance W and the current speed V of the own vehicle calculates the profile module 26 then a deceleration profile with which the vehicle 34 comfortably, in particular without abrupt acceleration changes, brought to a standstill. In this case, the speed profile can correspond to a curve suitably chosen from the comfort point of view, with the condition that the path obtained by integrating this speed curve until the stop time coincides with the stopping distance W.

The profile module 26 then outputs a (negative) target acceleration corresponding to this delay profile to the output stage 32 then, the corresponding commands to implement this target acceleration to the actuator systems 12 and 14 outputs. Typically, an intervention in the drive system and, if the braking torque of the motor is insufficient, an intervention in the brake system will initially take place.

2 (C) shows the vehicles 34 and 36 in the position in which they have actually come to a standstill. Comparing these positions with the pre-calculated stop positions 34 ' and 36 ' according to 2 B) , it turns out that in this example the extrapolation of the deceleration of the fore vehicle 36 that in the situation according to 2 B) was made, does not correspond to the actual happening. The front vehicle 36 has in fact been delayed less and only came to a halt in the forward position. Would be the stopping of the vehicle 34 solely through the profile module 26 had been controlled, so would be the own vehicle 34 now in the pre-calculated stop position 34 ' and its distance to the front vehicle 36 would be too large, so that the driver would feel prompted to start again to unlock the front vehicle.

Preventing this is the main task of the roll phase controller 28 which is activated at a certain time during the stopping process and then take control and ensure that the vehicle, if its speed has already decreased to a relatively low value, continues to roll with much less delay and then finally into the in 2 (C) shown position corresponding to the correct stopping distance D _A.

For the final braking of the vehicle 34 in the state, shortly before reaching the stopping distance D _A , the roll phase controller 28 an interface 38 on ( 1 ) specific to the nature and operation of the brake system and the associated actuator system 14 adapted and ensures that the vehicle is brought to a comfortable standstill with the lowest possible brake pressure.

To illustrate the mode of operation of the roll phase controller 28 are in 3 possible movements in the form of a speed / time diagram shown. The curve drawn in solid lines 36a is the speed curve for the front vehicle 36 that belong to the in 2 (C) has shown the situation. The driver of the front vehicle has initially braked relatively strong, what the Anhalteabsicht could be detected, but then released the brake pedal, with the result that the vehicle on the precalculated stop position 36 ' is rolled out.

The curve 34a shows the associated speed history for your own vehicle 34 , At time T ₀ , it was recognized that the fore vehicle is likely to stop, and it was the follower 22 on the profile module 26 switched. The professional module then calculated the deceleration profile, but is extrapolating the speed curve for the vehicle in front 36 gone out by the in 3 dash-dotted curve 36b is represented. Until the time T _a (= T _R ) was the delay of the own vehicle 34 determined by the delay profile calculated on the basis of this assumption.

Meanwhile, however, based on the data of the sensor system 10 found that the speed curve 36a the front of the vehicle in truth has flattened. This has meant that at the time T _R, the strategy selection module 30 the control of the profile module 26 to the roll phase controller 28 has passed. This then has the (negative) target acceleration gradually increased again and almost to 0, so that the vehicle 34 gently into a rolling phase, in which it is rolled out with only a very small delay. The distance to the front vehicle, which has come to a standstill at time T ₁ , was thereby still from the roll phase controller 28 supervised. At time T _A had the vehicle 34 the stopping distance D _A almost reached, except for a small difference amount D, which was still needed to the vehicle 34 finally to brake in the state. Thereupon, at the time T _A via the interface 38 the actuator system 14 activated to comfortably brake the vehicle in the state, so that the vehicle has finally come to a halt exactly at the correct stopping distance D _A.

In vehicles with automatic transmission and torque converter, the rolling phase may include a more or less long period of time in which the vehicle rolls on due to the idling torque generated by the torque converter at a constant speed. The control parameters of the roll phase controller 28 are then adapted so that at the beginning of the rolling phase, a smooth transition to this rolling speed.

If the idling thrust moment and thus the rolling speed is too high, for example on slopes, the Rollphasenregler during the entire rolling phase can cause a continuous slight braking, so that the speed from which must be braked at the time T _A in the state, not too large. In either case, the roll phase controller will control the deceleration of the vehicle in the initial phase of the roll phase so that the speed of the vehicle decreases monotonically and the vehicle does not accelerate again due to the effect of idle thrust torque.

The curve 36b in 3 illustrates a speed history in which the front vehicle 36 Braking is stronger than in the case of the curve 36a as it corresponds to the predicted speed course. Accordingly, the front vehicle comes to a standstill earlier and also the own vehicle must be brought earlier and within a shorter distance in the state. In this case, the profile module 26 That is a relatively strong deceleration of the vehicle 34 causes longer active, and the transition to the roll phase takes place at a later date, corresponding to the point T _b in 3 , The further speed course for the vehicle 34 then corresponds to the curve 34b ,

The curve 34c finally corresponds to the case that the front vehicle, stronger than predicted, according to the curve 36c , is delayed. Here the transition into the rolling phase takes place only at a later point in time, at point T _c . Even in this case, however, a still - but relatively short - roll phase is provided. In this way it is achieved that at the time when the own vehicle has almost reached the stopping distance D _A and the final braking begins in the state, In any case, the same conditions exist with regard to the speed V of the own vehicle and also with regard to the state of the brake system, regardless of the previous history. the interface 38 , which controls the final phase of the braking process, is specially adapted to these as it were standardized conditions and to the existing brake system in the vehicle.

In this way it is possible to use the interface 38 to optimize the same comfort for the use of different braking systems.

From the fact that even in the case in which the front vehicle is expected with the relatively steeply sloping speed curve 36c is delayed, nor a short roll phase is provided, naturally follows that the vehicle 34 in the preceding period in which the profile module 26 is active, must be delayed more than it would without roll phase the case. However, the delay profile obtained in this way, with a first relatively strong deceleration, which then changes into a rolling phase before the final standstill, is generally perceived as comfortable and also corresponds to the intuitive behavior of a trained driver.

The essential steps of the process described above in the data processing unit 16 executed procedure are in 4 shown again in a flow chart.

If the strategy selection module 30 detects that the fore vehicle will stop, so in step S1, the stop controller 24 and especially the profile module 26 activated, and this module calculates by extrapolating the deceleration of the fore vehicle 36 the delay profile, then the curve first 34b in 3 equivalent. At the same time, a provisional value is calculated for the time T _R at which the roll phase controller 28 should be activated. This time initially corresponds to the point T _b in 3 , The vehicle is then using the profile module 26 Delayed output delay according to the calculated delay profile. In this case, in step S2 is continuously monitored, as the speed V _{V of} the front vehicle 36 actually developed. If this speed has remained greater than expected due to extrapolation (curve 36a in 3 ), a branch is made to a step S3, and the value calculated for the time T _R is reduced, that is, the beginning of the rolling phase is advanced (for example, from T _b to T _a ).

Thereafter, it is checked in step S4 whether the time T _R for the start of the roll phase has already been reached.

If it shows in step S2 that the speed V _{V of} the preceding vehicle has developed as expected (corresponding to the curve 36b ), step S2 is followed directly by step S4. On the other hand, if it shows that the speed of the front vehicle is smaller than expected, for example, because the driver of the front vehicle has gone to full braking, it is checked in step S5 whether the situation can still be controlled by a later initiation of the roll phase or a new calculation the profile is required. In the former case, the value T _{R is} increased in step S6. Otherwise, a return is made to step S1, and the deceleration profile and the time T _R are recalculated based on the new deceleration data for the preceding vehicle. In this way it is prevented that the own vehicle runs too close to the front vehicle.

If it is determined in step S4 that the time T _R is not yet reached, a return to step S2, and depending on the result of the query in step S2, one of the above-described loops is run through again.

If it is found in step S4 that the time T _R for the start of the roll phase is reached, the control is to the roll phase controller 28 then the roll profile or, more precisely, a deceleration profile for the transition to the roll phase according to one of the curves 34a . 34b or 34c calculated (step S7).

Thereafter, in step S8, it is checked whether the distance D to the preceding vehicle 36 has become smaller than the stopping distance D _A plus the above-mentioned difference D. If this is not yet the case, the step S8 is repeated cyclically, that is, the rolling phase is continued. Otherwise, in step S9, the vehicle is finally braked to a standstill. In the case of the curve 34a this braking process would be initiated at time T _A.

In practice, the target acceleration is that of the profile module 26 can be output, limited by upper and lower limits. If the calculated deceleration profile required a (negative) acceleration below the lower limit, it is common in ACC systems for the driver to receive a warning requesting him to take control himself. In the embodiment described here, however, one still has a certain delay reserve, because in such extreme cases, the rolling phase (corresponding to the curve 34c ) could be omitted, so that the vehicle can still be brought to a standstill in time with less delay. According to an extension of the described embodiment can therefore be provided in step S1 that in the calculation of the delay profile, the roll phase is only included if the setpoint acceleration always remains above the lower limit value. If, on the other hand, the lower limit value is undershot, then the roll phase is suppressed (T _R ? ∞) and the deceleration profile is calculated without a roll phase. Only if the lower limit value for the target acceleration would have to be exceeded even then, the takeover request is issued to the driver.

Claims (9)

Device for speed and stopping control in motor vehicles, having a sensor system ( 10 ) for locating a front vehicle ( 36 ), a follower ( 22 ) for regulating the distance of the own vehicle ( 34 ) to the front vehicle ( 36 ) while driving, and a stop control ( 24 ), which brakes the own vehicle in the state when it is recognized that the front vehicle is stopping or stopping, characterized in that in the stop controller ( 24 ) a roll phase controller ( 28 ) is implemented, which keeps its speed approximately constant during a rolling phase shortly before the standstill of the own vehicle. Apparatus according to claim 1, characterized in that the stopping controller ( 24 ) next to the scroll phase controller ( 28 ) a profile module ( 26 ) for controlling the vehicle speed according to a deceleration profile, which is determined on the basis of a predicted course of the speed of the preceding vehicle ( 36 ) and that a strategy selection module ( 30 ) is adapted, during the stopping process of the profile module ( 26 ) on the roll phase controller ( 28 ) switch. Apparatus according to claim 2, characterized in that the profile module ( 26 ) is designed to calculate the deceleration profile taking into account a rolling phase beginning at a predetermined time (T _c ) before the vehicle is stationary. Device according to one of the preceding claims, characterized in that the roll phase controller ( 28 ) is adapted to the distance (D) to the front vehicle ( 36 ) and to terminate the rolling phase by initiating braking in the state when a predetermined distance (D _A + D) is reached to the front vehicle. Apparatus according to claim 4, characterized in that the roll phase controller ( 28 ) is adapted to regulate the deceleration of the vehicle so that the vehicle always has approximately the same speed at the time (T _A ), at which the braking starts in the state, regardless of the previous history. Apparatus according to claim 4 or 5, characterized in that the roll phase controller ( 28 ) is adapted to control the deceleration of the vehicle in the roll phase so that the braking system of the vehicle at the time (T _A ) at which the braking begins to stand, regardless of the previous history is always in substantially the same state , Device according to one of the preceding claims, characterized in that the roll phase controller ( 28 ) has adjustable control parameters, with which the transition from the present at the beginning of the rolling phase speed can be adapted to a roll speed in the course of the approximately maintained roll speed and roll speed to the properties of the vehicle transmission. Device according to one of the preceding claims, characterized in that the roll phase controller ( 28 ) an interface which can be adapted specifically to the respective braking system of the vehicle ( 38 ) for the control of the braking system when braking the vehicle in the state at the end of the rolling phase. Device according to one of the preceding claims, characterized in that it is designed to determine the instant (T _R ) at which the rolling phase begins as a function of the detected state of motion of the vehicle in front ( 36 ) to vary.