METHOD AND DEVICE FOR AUTOMATICALLY EMERGENCY STOPPING

Abstract

A method for automatically emergency stopping a motor vehicle from a starting speed to a standstill by a braking device of the motor vehicle is provided. The braking device is actuated to carry out a delay profile with at least two delay phases. During a delay increase phase the delay until a threshold delay is increased and during a delay decrease phase, lasting until standstill, the delay is reduced to zero. The temporal courses of the delay are determined during the delay increase and the delay decrease at least sectionally as nth degree polynomials, where n>0, depending on the starting speed, in such a way that a stopping duration, which represents a time duration necessary for emergency stopping, does not fall below a predetermined minimum stopping duration and a distance covered during the stopping duration does not exceed a predetermined maximum stopping distance.

Claims

1-10. (canceled)

11. A method for automatically emergency stopping a motor vehicle from a starting speed to a standstill by a braking device of the motor vehicle, the method comprising: determining that the vehicle should be automatically stopped; and actuating, responsive to the determination that the vehicle should be automatically stopped, the braking device to carry out a delay profile having at least two delay phases, wherein, during a delay increase phase, a first delay until a threshold delay is increased and during a delay decrease phase a second delay is reduced to zero, wherein temporal courses of the delay are determined during the delay increase and the delay decrease at least sectionally as nth degree polynomials, where n>0, depending on a starting speed of the vehicle in such a way that a stopping duration, which represents a time duration necessary for emergency stopping, does not fall below a predetermined minimum stopping duration and a distance covered during the stopping duration does not exceed a predetermined maximum stopping distance.

12. The emergency stopping method of claim 11, wherein a delay stopping phase is run through between the delay increase phase and the delay decrease phase, wherein in the delay stopping phase the delay does not deviate from the threshold delay by more than a predetermined value.

13. The emergency stopping method of claim 11, the threshold delay is a function of the starting speed and exceeds a predetermined minimum delay.

14. The emergency stopping method of claim 11, wherein the first delay during the delay increase phase increases with an increase jolt, which is selected between a minimum increase jolt and a maximum increase jolt, and wherein the minimum increase jolt is between 0.4 and 0.5 m/s.sup.3, and the maximum increase jolt is between 0.7 and 0.8 m/s.sup.3.

15. The emergency stopping method of claim 11, wherein the second delay during the delay decrease phase decreases with a decrease jolt, which is selected between a minimum decrease jolt and a maximum decrease jolt, wherein the minimum decrease jolt is between −0.4 and 0.5 m/s.sup.3, and the maximum decrease jolt is between −0.7 and −0.8 m/s.sup.3.

16. The emergency stopping method of claim 15, wherein the increase jolt and the decrease jolt are chosen to be constant when the starting speed is below an upper threshold speed, the minimum delay is determined as the threshold delay and the duration of the delay stopping phase as a function of the starting speed when the starting speed is below a lower threshold speed, wherein the stopping duration is allowed to fall below the predetermined minimum stopping duration, the threshold delay is determined as a function of the starting speed in such a way that the minimum stopping duration is not fallen below when the starting speed is above the lower threshold speed and below an average threshold speed, the threshold delay during the delay stopping phase corresponds to a maximum delay and the duration of the delay stopping phase is determined as the function of the starting speed when the starting speed is above the average threshold speed and below the upper threshold speed.

17. The emergency stopping method of claim 16, wherein when the starting speed is above the upper threshold speed, the threshold delay, the maximum delay, or the increase jolt and the decrease jolt exceed respective maximum values, which are determined as a function of the starting speed in such a way that the maximum stopping distance is not exceeded.

18. The emergency stopping method of claim 17, wherein the increase jolt and the decrease jolt are selected as a function of the starting speed.

19. The emergency stopping method of claim 11, wherein after triggering the emergency stopping method, a roll phase is performed before the delay increase phase, wherein in the roll phase a drive torque of a drive device of the motor vehicle is set to zero and a braking actuation is performed with to prevent a vehicle acceleration caused by externally acting forces.

20. A device for automatically emergency stopping a motor vehicle from a starting speed to a standstill by a braking device of the motor vehicle, wherein the device is configured to: actuate the braking device to carry out a delay profile having at least two delay phases, wherein, during a delay increase phase, a first delay until a threshold delay is increased and during a delay decrease phase a second delay is reduced to zero, wherein temporal courses of the delay are determined during the delay increase and the delay decrease at least sectionally as nth degree polynomials, where n>0, depending on a starting speed of the vehicle in such a way that a stopping duration, which represents a time duration necessary for emergency stopping, does not fall below a predetermined minimum stopping duration and a distance covered during the stopping duration does not exceed a predetermined maximum stopping distance, wherein the device is connected to a sensor that records the driving speed and to a control device for a drive device of the motor vehicle, and to a control device for a braking system.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0026] Here are shown:

[0027] FIG. 1: a delay time diagram of a delay profile with an emergency stopping method according to the invention;

[0028] FIG. 2: a delay time diagram of a delay profile with a very low starting speed;

[0029] FIG. 3: a delay time diagram of a delay profile with a low starting speed;

[0030] FIG. 4: a delay time diagram of a delay profile with an average starting speed;

[0031] FIG. 5: a delay time diagram of a delay profile with a high starting speed;

[0032] FIG. 6: a block wiring diagram of a device for carrying out the emergency stopping method according to the invention.

DETAILED DESCRIPTION

[0033] FIG. 1 shows a delay time diagram of a delay profile with an emergency stopping method according to the invention. The x-axis is the time in seconds, the y-axis the delay in [m/s.sup.2]. The roll phase Δt.sub.r is depicted on the very left on the time axis, which various time durations Δt.sub.z1, Δt.sub.z2, Δt.sub.z3, Δt.sub.z4 follow for the delay increase phase for different delay profiles.

[0034] In the delay profile 10 (dot-dashed line), a constant increase of the delay is carried out starting from 0 up to the value of the minimum delay a.sub.min of 0.75 m/s.sup.2. The value of the increase jolt j.sub.z1 is 0.75 m/s.sup.2/6s, so j.sub.z1=0.125 m/s.sup.3. In this delay profile 10 for very low starting speeds v.sub.0, the delay increase phase Δt.sub.z1 follows a similarly long delay decrease phase Δt.sub.a1 with the same size decrease jolt j.sub.a1 according to the amount. This entire duration of the braking process emerges from the sum of the phases Δt.sub.r+Δt.sub.z1+Δt.sub.a1 and, in the example depicted, result in 11s. The allocated starting speed vol can be understood as the surface between the acceleration zero line 11 and the two lines j.sub.z1 and j.sub.a1, i.e., the surface of the triangle formed thereby.

[0035] In the delay profile 12 (dotted line), after the end of the roll phase Δt.sub.r, a constant increase of the delay is carried out starting from 0 up to a delay value a.sub.2 of about 1.1 m/s.sup.2. The value of the increase jolt j.sub.z2 is about 1.1 m/s.sup.2/5.3s, so j.sub.z2=0.21 m/s.sup.3. In this delay profile 12 for somewhat higher starting speeds vol, a delay stopping phase Δt.sub.h2 follows the delay increase phase Δt.sub.z2, the delay stopping phase following a delay decrease phase Δt.sub.a2. The entire duration of the braking process emerges from the sum of the phases Δt.sub.r+Δt.sub.z2+Δt.sub.a2 and once again results in 11s. The allocated starting speed vol can be defined as the surface between the acceleration zero line and the trapezium spanned by the three lines j.sub.z2, a.sub.2 and j.sub.a2.

[0036] In order to achieve a deceleration duration of 11s, the jolt with the delay increase and decrease j.sub.z2 and jag can thus be increased, whereby the delay stopping phase Δt.sub.h2 emerges.

[0037] With an even higher starting speed, in the delay profile 14 (dashed line), the jolt is increased further still, and since the delay is not to exceed the maximum delay a.sub.max, a widening of the delay stopping phase Δt.sub.h emerges automatically. For the delay profile 16 (solid line), the same applies for an even higher starting speed.

[0038] In FIG. 2, an alternative delay profile 18 (with a solid line) is depicted for very low starting speeds that are below a lower threshold speed v.sub.1. In contrast to the delay profiles 10, 12, 14, 16 of FIG. 1, the delay profile 18 starts from constant increase jolt values j.sub.z and decrease jolt values j.sub.a, which can be depicted by lines with constant inclination.

[0039] Based on the principle that the threshold delay a.sub.g is not supposed to be smaller than the predetermined minimum delay a.sub.min, over time the delay profile 18 causes too great a deceleration of the vehicle in an integrated manner, such that this would come to a sudden standstill. Thus, the delay stopping phase Δt.sub.h is shortened to the extent that a gentle ending of the deceleration process is achieved in the delay decrease phase Δ.sub.ta, even if this happens before the minimum stopping duration t.sub.min (at about 10s in the depicted example). The lower the starting speed, the more the delay stopping phase Δt.sub.h is shortened, and thus the delay decrease phase Δt.sub.a moves in the direction labelled with 20.

[0040] In FIG. 3, a delay profile 22 is depicted for a range of low starting speeds that are higher than the threshold speed v.sub.1, at which the minimum stopping duration t.sub.min is just achieved. Here, the threshold delay a.sub.g is now determined as a function of the starting speed, wherein the threshold delay a.sub.g increases with increasing starting speed. With an average starting speed v.sub.2, the threshold delay a.sub.g reaches the maximum delay a.sub.max, wherein, in the entire speed range between v.sub.1 and v.sub.2, the minimum stopping duration t.sub.min is constantly achieved (i.e., the vehicle is decelerated to a standstill exactly within this time period), wherein the threshold delay a.sub.g changes in the region labelled with the reference numeral 23.

[0041] In FIG. 4, a delay profile 24 is depicted for a range of average starting speeds that are higher than the threshold speed v.sub.2 at which the vehicle is brought to a standstill upon reaching the minimum stopping duration t.sub.min. With higher starting speeds v.sub.0>v.sub.2, a longer stopping duration is necessary in order to bring the vehicle to a standstill, wherein the braking distance gets longer. Here, the delay stopping phase Δt.sub.h is correspondingly lengthened as a function of the starting speed, which is indicated by the arrow 25. The delay profile 24 is delimited by an upper threshold speed v.sub.3, at which the braking distance reaches the maximum stopping distance s.sub.max.

[0042] In FIG. 5, several delay profiles 26a, 26b, 26c are depicted for a range of high starting speeds v.sub.0 that are higher than the threshold speed v.sub.3, at which the braking distance reaches the maximum stopping distance s.sub.max. This maximum stopping distance s.sub.max is not to be exceeded, such that by now greater threshold delays have to be used, which exceed the maximum delay a.sub.max. In addition, it is expedient to also increase the jolt values in the delay increase phase Δt.sub.z and the delay decrease phase Δt.sub.a, as depicted in the delay profiles 26b, 26c.

[0043] In the following Table 1, the emerging values for the roll phase Δt.sub.r, the delay increase phase Δt.sub.z, the increase jolt j.sub.z, the delay stopping phase Δt.sub.h, the threshold delay a.sub.g, the delay decrease phase Δt.sub.a, the decrease jolt j.sub.a, the total duration of the braking process t.sub.b=Δt.sub.r+Δt.sub.z+Δt.sub.h+Δt.sub.a and the emerging braking distance s are depicted in a table for various starting speeds v.sub.0.

TABLE-US-00001 TABLE 1 V.sub.0 Δt.sub.r Δt.sub.z j.sub.z Δt.sub.h a.sub.g Δt.sub.a j.sub.a t.sub.b s [km/h] [s] [s] [m/s.sup.3] [s] [m/s.sup.2] [s] [m/s.sup.3] [s] [m] 10 1 1.3 0.60 2.5 0.75 1.3 0.60 6.0 10 30 1 1.7 0.60 6.7 1.00 1.7 0.60 11.0 50 80 1 2.5 0.60 12.3 1.50 2.5 0.60 18.3 215 120 1 2.5 0.60 19.7 1.50 2.5 0.60 25.7 445 140 1 3.3 0.60 16.1 2.00 3.3 0.60 23.8 482

[0044] In the following Table 2, two different delay profiles are depicted in comparison for the same starting speeds v.sub.0=30 km/h, that is in the upper row, a delay profile with greater jolt vales j.sub.z, j.sub.a and a lower threshold delay a.sub.g.

TABLE-US-00002 TABLE 2 V.sub.0 Δt.sub.r Δt.sub.z j.sub.z Δt.sub.h a.sub.g Δt.sub.a j.sub.a t.sub.b s [km/h] [s] [s] [m/s.sup.3] [s] [m/s.sup.2] [s] [m/s.sup.3] [s] [m] 30 1 1.7 0.60 6.7 1.0 1.7 0.60 11.0 50 30 1 4.4 0.34 1.1 1.5 4.4 0.34 11.0 46

[0045] In the following Table 3, values for the threshold speeds v.sub.1, v.sub.2, v.sub.3 and the corresponding parameters are depicted in three rows.

TABLE-US-00003 TABLE 3 V.sub.0 Δt.sub.r Δt.sub.z j.sub.z Δt.sub.h a.sub.g Δt.sub.a j.sub.a t.sub.b s [km/h] [s] [s] [m/s.sup.3] [s] [m/s.sup.2] [s] [m/s.sup.3] [s] [m] 23.6 1 1.3 0.60 1.3 0.75 1.3 0.60 11.0 39 40.5 1 2.5 0.60 5.0 1.5 2.5 0.60 11.0 68 120.0 1 2.5 0.60 19.7 1.5 2.5 0.60 25.7 445

[0046] FIG. 6 illustrates a device 28 for carrying out the method, the device being connected to a vehicle speed sensor 30 for recording the starting speed v.sub.0. The device 28 has an output for controlling a control device 32 for a drive device of the motor vehicle, in order to set the drive device without torque. The device 28 has a further output for controlling a control device 34 for a braking system and an output for controlling a control device 35 for a setting braking system. Thus, the braking system is controlled according to the method according to the invention. The essential delay values can be obtained either by differentiation of the speed values of the sensor 30 or the device 28 can be connected to a separate acceleration sensor 36.

[0047] The device 28 is further connected to a switch 38 for manually triggering and/or ending the emergency stopping method and can be connected to a driver sensor system device 40. The emergency stop method according to the invention can be activated both by means of the switch 38 and by the driver sensor system device 40, wherein the current starting speed v.sub.0 is measured at this moment by the speed sensor 30 and is compared with the values for the threshold speeds v.sub.1, v.sub.2, v.sub.3 stored in a calculation unit 42 of the device 28. From this, the calculation unit 42 calculates the corresponding delay profile depending on the starting speed v.sub.0 ascertained and correspondingly controls the control device 34 for the braking system, wherein the emerging acceleration values are ascertained by the acceleration sensor 36. It is alternatively also possible to use a look-up table with pre-saved values instead of the calculation unit 42.

[0048] Although the invention has been illustrated and explained in more detail by preferred exemplary embodiments, the invention is not limited by the disclosed examples, and other variations can be derived from this by the person skilled in the art without leaving the scope of protection of the invention. It is thus clear that a plurality of variation possibilities exist. It is also clear that embodiments mentioned by way of example really only constitute examples, which are not to be understood in any other way than limiting the scope of protection, for example, the application possibilities or the configuration of the invention. Instead, the description above and the description of the figures put the person skilled in the art in a position to concretely implement the exemplary embodiments, wherein the person skilled in the art, with an understanding of the disclosed idea of the invention, can undertake various amendments, for example with regard to the function or the arrangement of individual elements mentioned in an exemplary embodiment without leaving the scope of protection which is defined by the claims and the legal equivalences, such as further explanations in the description, for example.