METHOD AND APPARATUS FOR THE CLOSED-LOOP AND/OR OPEN-LOOP CONTROL OF A LATERAL GUIDANCE OF A VEHICLE WITH THE AID OF A LANE-KEEPING ASSIST, AND LANE-KEEPING ASSIST

Abstract

A method for the closed-loop and/or open-loop control of a lateral guidance of a vehicle with the aid of a lane-keeping assist. In the process, a detection signal is read in which represents hands-off and/or hands-on driving of the vehicle. If the detection signal represents the hands-off driving, then a closed-loop control signal is provided for controlling the lateral guidance in closed loop. On the other hand, if the detection signal represents the hands-on driving, then an open-loop control signal is provided for controlling the lateral guidance in open loop.

Claims

1-11. (canceled)

12. A method for the closed-loop and/or open-loop control of a lateral guidance of a vehicle with the aid of a lane-keeping assist, the method comprising: reading in of a detection signal that represents hands-off or hands-on driving of the vehicle; and providing at least one of: a closed-loop control signal for controlling the lateral guidance in closed loop when the detection signal represents the hands-off driving, and an open-loop control signal for controlling the lateral guidance in open loop when the detection signal represents the hands-on driving.

13. The method as recited in claim 12, further comprising: sensing a holding force exerted by at least one hand on a steering wheel of the vehicle, the detection signal being provided in an output step as a function of the holding force, in consideration of at least one of a predetermined debounce time and a predetermined threshold value for the holding force.

14. The method as recited in claim 12, wherein in the reading in step, a predetermined control profile activated by the driver is read in, the open-loop control signal being provided in the providing step using the control profile to control the lateral guidance of the vehicle in open loop according to the control profile.

15. The method as recited in claim 14, wherein the control profile represents a characteristic of a steering torque for the steering assistance as a function of a lateral position of the vehicle in a traffic lane.

16. The method as recited in claim 15, wherein the steering torque within a predetermined distance to a center of the traffic lane is equal to zero.

17. The method as recited in claim 14, wherein in the reading in step, at least one further predetermined control profile activated by the driver is read in, the control profile and the further control profile differing from each other, the open-loop control signal being provided in the providing step using the further control profile to control the lateral guidance of the vehicle in open loop according to the further control profile.

18. The method as recited in claim 12, wherein in the reading in step, an activation signal is read in which represents an activation by the driver of a closed-loop steering-control function of the lane-keeping assist, the closed-loop control signal being provided in the providing step using the activation signal, regardless of the detection signal.

19. An apparatus which is designed for the closed-loop and/or open-loop control of a lateral guidance of a vehicle with the aid of a lane-keeping assist, the apparatus designed to: read in of a detection signal that represents hands-off or hands-on driving of the vehicle; and provide at least one of: a closed-loop control signal for controlling the lateral guidance in closed loop when the detection signal represents the hands-off driving, and an open-loop control signal for controlling the lateral guidance in open loop when the detection signal represents the hands-on driving.

20. A lane-keeping assist, comprising: a closed-loop control unit for controlling a lateral guidance of a vehicle in closed loop; an open-loop control unit for controlling the lateral guidance in open loop; and an apparatus which is designed for the closed-loop and/or open-loop control of the lateral guidance of a vehicle with the aid of a lane-keeping assist, the apparatus designed to read in of a detection signal that represents hands-off or hands-on driving of the vehicle, and provide at least one of: a closed-loop control signal for controlling the lateral guidance in closed loop when the detection signal represents the hands-off driving, and an open-loop control signal for controlling the lateral guidance in open loop when the detection signal represents the hands-on driving, the apparatus being coupled to at least one of the closed-loop control unit and the open-loop control unit.

21. A non-transitory machine-readable storage medium on which is stored program code for the closed-loop and/or open-loop control of a lateral guidance of a vehicle with the aid of a lane-keeping assist, the program code, when executed by a computer, causing the computer to perform: reading in of a detection signal that represents hands-off or hands-on driving of the vehicle; and providing at least one of: a closed-loop control signal for controlling the lateral guidance in closed loop when the detection signal represents the hands-off driving, and an open-loop control signal for controlling the lateral guidance in open loop when the detection signal represents the hands-on driving.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 shows a schematic representation of a lane-keeping assist according to one exemplary embodiment of the present invention.

[0029] FIG. 2 shows a schematic representation of a lane-keeping assist with variable control profile according to one exemplary embodiment of the present invention.

[0030] FIG. 3a, 3b, 3c show schematic representations of control profiles according to various exemplary embodiments of the present invention.

[0031] FIG. 4 shows a block diagram of an apparatus according to one exemplary embodiment of the present invention.

[0032] FIG. 5 shows a flow chart of a method according to one exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0033] In the following description of preferred exemplary embodiments of the present invention, the same or similar reference numerals are used for the similarly functioning elements shown in the various figures, a description of these elements not being repeated.

[0034] FIG. 1 shows a schematic representation of a lane-keeping assist 100 according to one exemplary embodiment of the present invention. Lane-keeping assist 100 is used to assist a driver in the lateral guidance of his vehicle. According to this exemplary embodiment, lane-keeping assist 100 includes an apparatus 102, a closed-loop control unit 104, an open-loop control unit 106 as well as a hand-detection device 108 which is designed to sense a holding force exerted by at least one hand on a steering wheel of the vehicle, for instance, a manual torque or a deformation of the steering wheel, and to output a detection signal 110 to apparatus 102 as a function of the sensed holding force. For example, detection signal 110 represents hands-off driving of the vehicle when the holding force is less than a predetermined threshold value, and conversely, hands-on driving of the vehicle when the holding force exceeds the threshold value.

[0035] Closed-loop control unit 104 is designed to generate a closed-loop control signal 112 for controlling the lateral guidance in closed loop. Analogous to that, open-loop control unit 106 is designed to generate an open-loop control signal 114 for controlling the lateral guidance in open loop. For example, each of the two signals 112, 114 represents an additional steering torque, also known as lane-keeping-assist-system torque or LKS torque for short, counter to the manual torque.

[0036] Apparatus 102 is designed, using detection signal 110, to provide closed-loop control signal 112 when detection signal 110 represents the hands-off driving, i.e., when, based on the holding force, it may be assumed that the driver has released the steering wheel, as is the case by way of example in FIG. 1. For example, closed-loop control signal 112 may be used for the autonomous center guidance of the vehicle, by which, for the most part, the vehicle is able to be kept automatically in the center of the lane.

[0037] On the other hand, if detection signal 110 represents the hands-on driving, that is, if from the holding force sensed by hand-detection device 108, it follows that the driver is gripping the steering wheel, then instead of closed-loop control signal 112, apparatus 102 provides open-loop control signal 114 by which, for example, a lane-departure-prevention function of lane-keeping assist 100 may be controlled.

[0038] According to one exemplary embodiment, open-loop control unit 106 is designed to calculate a steering torque, used for the steering assistance, from a characteristic curve which may be established in the application, for instance, from what is referred to as a bathtub curve. In this context, the closer the vehicle comes to the edge of the lane, the greater the steering torque becomes. On the other hand, in the center of the lane, the steering torque is zero or at least very small. Such an open-loop control method offers the advantage of low complexity and correspondingly easy realizability.

[0039] Hand-detection device 108 detects whether or not the driver is co-steering, for instance, based on a measured steering-wheel torque. If the driver is driving hands-off, apparatus 102 switches to closed-loop control by providing closed-loop control signal 112, in order to keep the vehicle in the lane as well as possible. On the other hand, if hand-detection device 108 detects that the driver is co-steering, then apparatus 102 switches to open-loop control by providing open-loop control signal 114, in order to ensure a good and consistent driving feel.

[0040] According to one exemplary embodiment, in the case of the hands-off/hands-on detection described above, a debounce time and the thresholds of the manual torque are selected in such a way that on one hand, the switchover from open-loop control to closed-loop control does not take place too quickly, for instance, when the driver only briefly removes his hands from the steering wheel, but on the other hand, also does not take place too slowly, so that the closed-loop control intervenes in sufficient time, before the stability of the vehicle is jeopardized. For example, the debounce time is set to less than 5 s, and is therefore considerably shorter than the time necessary for generating a hands-off warning directed to the driver.

[0041] FIG. 2 shows a schematic representation of a lane-keeping assist 100 with variable control profile according to one exemplary embodiment of the present invention. In contrast to the lane-keeping assist described with reference to FIG. 1, a first control profile 202, a second control profile 204 and a third control profile 206 are stored by way of example in open-loop control unit 106 according to FIG. 2. A profile-activation unit 208 of open-loop control unit 106 is designed to receive from a setting unit 209, information 210 about a profile selection made by the driver, and using information 210, to activate a control profile corresponding to the profile selection, here first control profile 202, as example. Profile-activation unit 208 transmits first control profile 202 in the form of open-loop control signal 114 to apparatus 102.

[0042] According to this exemplary embodiment, first control profile 202 is a profile without dead zone, second control profile 204 is a profile with small dead zone and third control profile 206 is a profile with large dead zone. The differences between the three control profiles 202, 204, 206 are explained in greater detail below with reference to FIGS. 3a through 3c.

[0043] In contrast to FIG. 1, as example, detection signal 110 represents hands-on driving of the vehicle. Accordingly, apparatus 102 provides open-loop control signal 114 representing first control profile 202.

[0044] Apparatus 102 and closed-loop control unit 104 are connected via a switch 212 to a signal output 213 of lane-keeping assist 100. For example, signal output 213 is coupled to a steering system of the vehicle. Switch 212 is coupled to an activation unit 214 which is operable by the driver and which is designed, upon operation, to transmit an activation signal 216 to switch 212. Switch 212 is designed, in response to the reception of activation signal 216, to couple signal output 213 directly to closed-loop control unit 104. In this manner, a closed-loop control of the steering of the vehicle is made possible with the aid of closed-loop control signal 112, regardless of a detection signal 110 present at apparatus 102.

[0045] As example, in FIG. 2, signal output 213 is coupled via switch 212 to apparatus 102. Accordingly, in FIG. 2, open-loop control signal 114 is provided via signal output 213.

[0046] By the use of lane-keeping assist 100 according to FIG. 2, the driver himself is able to set a profile of the steering assistance as needed. If he himself would like to do no or scarcely any steering, then he may select the closed-loop control. If he would like to steer only a little, then he may select first control profile 202 without dead zone. If he would like to co-steer a little more, then he may activate control profile 204 with small dead zone. If, for the most part, he would like to steer himself, then he may select control profile 206 with large dead zone.

[0047] According to one exemplary embodiment, for the open-loop control based on a predicted position of the vehicle in relation to a center of a lane, it may be determined whether, after a certain prediction time, the vehicle is located in the dead zone or outside of the dead zone. Within the dead zone, no steering assistance takes place; outside of the dead zone, the steering assistance is active, that is, for example, the additional steering torque is generated.

[0048] The predicted position is used to compensate for a latency in the overall vehicle system.

[0049] FIGS. 3a, 3b, 3c show schematic representations of control profiles 202, 204, 206 according to various exemplary embodiments of the present invention. A respective characteristic of control profiles 202, 204, 206, described with reference to FIG. 2, is represented as torque profile in FIGS. 3a through 3c. In this context, a y-axis represents an LKS steering-wheel torque and an x-axis represents a predicted lateral distance of the vehicle to the lane center, which corresponds here to the origin.

[0050] FIG. 3a shows first control profile 202 without dead zone. Control profile 202 has an essentially V-shaped form, made up of two straight lines disposed in mirror symmetry relative to each other, which intersect in the origin, that is, to the left of the y-axis, the steering torque drops linearly to zero with decreasing distance to the lane center, and to the right of the y-axis, rises linearly with increasing distance to the lane center.

[0051] In contrast to FIG. 3a, the two straight lines of the control profiles shown in FIGS. 3b and 3c do not intersect in the origin, but rather on a negative section of the y-axis not shown here. As an example, control profile 204 has a small dead zone 304 and control profile 206 has a large dead zone 306. The two dead zones 304, 306 are defined by a distance between the intersecting points of the two straight lines with the x-axis. According to this exemplary embodiment, the steering torque within dead zones 304, 306 is equal to zero.

[0052] FIG. 4 shows a block diagram of an apparatus 102 according to one exemplary embodiment of the present invention. For example, apparatus 102 is an apparatus, described with reference to FIGS. 1 through 3c, for controlling a lateral guidance of a vehicle in closed loop or open loop with the aid of a lane-keeping assist. Apparatus 102 includes a read-in unit 402 and a provision unit 404. Read-in unit 402 is designed to read in detection signal 110 and to transmit it to provision unit 404. Provision unit 404 is designed, using detection signal 110, to provide closed-loop control signal 112 when detection signal 110 represents hands-off driving of the vehicle. Depending on the specific embodiment, provision unit 404 is designed, using detection signal 110, to additionally or alternatively provide open-loop control signal 114 when detection signal 110 represents hands-on driving.

[0053] FIG. 5 shows a flow chart of a method 500 according to one exemplary embodiment of the present invention. Method 500 for controlling a lateral guidance of a vehicle in closed loop or open loop with the aid of a lane-keeping assist may be carried out, controlled or implemented, for example, by an apparatus as described previously on the basis of FIGS. 1 through 4.

[0054] In a step 502, a detection signal is read in which represents hands-off or hands-on driving of the vehicle. If the detection signal represents the hands-off driving, then in a step 504, a closed-loop control signal is provided for controlling the lateral guidance in closed loop. On the other hand, if the detection signal represents the hands-on driving, then in step 504, an open-loop control signal is provided for controlling the lateral guidance in open loop.

[0055] The exemplary embodiments described and illustrated in the figures are selected only by way of example. Different exemplary embodiments may be combined with each other completely or in terms of individual features. One exemplary embodiment may also be supplemented by features from another exemplary embodiment.

[0056] Moreover, the method steps presented here may be repeated, as well as executed in a sequence other than that described.

[0057] If an exemplary embodiment includes an “and/or” link between a first feature and a second feature, it is to be read that the exemplary embodiment according to one embodiment has both the first feature and the second feature, and according to a further embodiment, has either only the first feature or only the second feature.