Adaptive driving assistance device and procedure

Abstract

An adaptive driver assistance system that includes the following: a sensor (245, 410) configured to detect an object within a first vehicle path; a processor (420) configured to generate a second vehicle path in response to the detection of the object, such that the second vehicle path avoids the object, the processor further configured to generate an initial steering torque in response to the second vehicle path in order to adapt the initial steering torque in order to generate an adapted steering torque in response to the initial steering torque exceeding a torque limit; and a vehicle control unit for controlling a host vehicle steering system to follow the second vehicle signal path in response to the adapted steering torque; where the adaptation is a first-order adaptation in response to a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque, or where the adjustment is a second-order adjustment in response to a damping ratio, a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque.

Description

[0001] The present disclosure relates generally to the programming of autonomous vehicle control systems. More specifically, aspects of this disclosure relate to systems, methods, and devices for path shaping for a vehicle equipped with an automated driver assistance system by reducing lateral acceleration and steering oscillations in response to rapid path changes.

[0002] The operation of modern vehicles is becoming increasingly automated, meaning they are able to control driving with less and less driver intervention. Vehicle automation has been divided into numerical levels, ranging from zero, corresponding to no automation with full human control, to five, corresponding to full automation without any human control. Various automated driver assistance systems, such as cruise control, adaptive cruise control, and parking assistance, correspond to lower levels of automation, while truly "driverless" vehicles correspond to higher levels.

[0003] Algorithms for automated driver assistance systems (ADAS), such as Lane Change on Demand (LCoD) and collision avoidance steering, typically determine a vehicle path in response to the detection of obstacles, lane markings, road curvature, and other external factors. Often, these functions can initiate sudden changes in the vehicle's path that do not align with the expectations of the vehicle occupants and may alarm and / or disturb them. In some cases, unstable control behavior and reduced operational availability due to disengagements caused by sudden path changes can occur during ADAS operation. Addressing these issues and providing a methodology for vehicle path shaping with automatic lateral control adjustment in response to rapid trajectory changes during automated driver assistance operation would be desirable.

[0004] DE 10 2014 206 338 A1 relates to a method and a corresponding device for assisting a driver of a vehicle during an evasive maneuver.

[0005] DE 10 2011 080 789 A1 describes a method in which the driving behavior of a vehicle is influenced depending on environmental data in order to support an evasive maneuver as soon as a risk of collision is detected based on the data from one or more environmental sensors and the data from one or more vehicle sensors.

[0006] DE 10 2017 011 570 A1 concerns a procedure for operating an assistance system of a vehicle.

[0007] The objective can be considered to be to provide an alternative driver assistance device and a method that improves vehicle stability during rapid trajectory changes. This objective is achieved by the subject matter of claim 1 and claim 8.

[0008] This paper presents learning systems for autonomous vehicle control systems and the associated control logic for providing autonomous vehicle control, methods for manufacturing and operating such systems, and motor vehicles equipped with onboard control systems. As an example, and without limitation, a motor vehicle with onboard vehicle control learning and control systems is presented to perform automatic lateral steering adjustment in response to rapid trajectory changes for an ADAS-equipped vehicle.

[0009] The adaptive driving assistance device according to the invention comprises a sensor configured to detect an object within a first vehicle path, a processor configured to generate a second vehicle path in response either to the detection of the object, so that the second vehicle path avoids the object, or to a trajectory shift initiated by the user, the processor further configured to generate an initial steering torque in response to the second vehicle path, to adapt to the initial steering torque, to generate an adapted steering torque in response to the initial steering torque exceeding a torque limit, and a vehicle controller for controlling a host vehicle steering system to follow the second vehicle signal path in response to the adapted steering torque.The adaptation is either a first-order adaptation in response to a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque, or a second-order adaptation in response to a damping ratio, a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque.

[0010] According to one embodiment, the initial steering torque is generated by a lateral controller in response to a lateral vehicle position and a vehicle course error.

[0011] According to one embodiment, the torque limit is a torque rate limit.

[0012] According to one embodiment, the sensor is a camera and the object is detected using image processing techniques.

[0013] According to one embodiment, the sensor is a lidar and the object is detected in response to a depth map generated by the lidar.

[0014] According to one embodiment, the adapted steering torque is an optimized torque command for a rapid change of path.

[0015] According to one embodiment, the adjustment compensates for a phase lag introduced by a rapid change in the trajectory path.

[0016] According to one embodiment, the adapted steering torque is coupled with an electronic power steering system to control a rate of change of a steering angle.

[0017] The method according to the invention comprises: Detect, by a sensor, a rapid path shift from a primary vehicle path; generate, by a processor, a secondary vehicle path in response to the rapid path shift detection; generate, by the processor, an initial steering torque in response to the secondary vehicle path; perform, by the processor, an adjustment to the initial steering torque to generate an adapted steering torque in response to the initial steering torque exceeding a torque limit; and control, by a vehicle controller, a host vehicle steering system to follow the secondary vehicle signal path in response to the adapted steering torque;wherein the adaptation is a first-order adaptation in response to a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque, or wherein the adaptation is a second-order adaptation in response to a damping ratio, a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque.

[0018] According to one embodiment, the method further comprises detecting an object within a first vehicle path by a sensor; generating a second vehicle path by a processor either in response to the detection of the object, so that the second vehicle path avoids the object, or in response to a user-initiated trajectory shift; generating an initial steering torque by the processor in response to the second vehicle path; performing an adaptation on the initial steering torque by the processor to generate an adapted steering torque in response to the initial steering torque exceeding a torque rate limit; and controlling a host vehicle steering system by a vehicle controller to follow the second vehicle signal path in response to the adapted steering torque.

[0019] According to one embodiment, the initial steering torque is generated by a lateral controller in response to a lateral vehicle position and a vehicle course error.

[0020] According to one embodiment, the adaptation is a first-order adaptation in response to a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque.

[0021] According to one embodiment, the adaptation is a second-order adaptation in response to a damping ratio, a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque.

[0022] According to one embodiment, the sensor is a camera and the object is detected using image processing techniques.

[0023] According to one embodiment, the sensor is a lidar and the object is detected in response to a depth map generated by the lidar.

[0024] According to one embodiment, the adapted steering torque is an optimized torque command for a rapid change of path.

[0025] According to one embodiment, the adjustment compensates for a phase lag introduced by a rapid change in the trajectory path.

[0026] According to one embodiment, the adapted steering torque is coupled with an electronic power steering system to control a rate of change of a steering angle.

[0027] As an application of the driving assistance device and method according to the invention, an adaptive driving assistance system for executing an adaptive driving assistance algorithm in a host vehicle is provided, comprising a first sensor configured to generate a depth map of a field of view, a second vehicle sensor configured to determine a vehicle speed, a processor for detecting an object within the field of view in response to the depth map, wherein the processor is further configured to generate a vehicle path so that the host vehicle avoids the object or follows a new trajectory requested by the user, and a vehicle controller configured to generate an initial steering torque in response to the vehicle path.to compare the initial steering torque with a torque rate limit and to generate an adapted steering torque in response to the vehicle speed and the initial steering torque exceeding the torque rate limit, and a steering control to adjust a host vehicle steering angle in response to the initial steering torque and the adapted steering torque.

[0028] According to one embodiment, the steering control is an electronic power steering system.

[0029] The above advantage and other advantages and features of the present disclosure will be evident from the following detailed description of the preferred embodiments when considered in conjunction with the accompanying figures.

[0030] The above-mentioned and other features and advantages of this invention, and the way in which they are achieved, will become clearer and the invention will be better understood by referring to the following description of embodiments of the invention in conjunction with the accompanying drawings. Fig. Figure 1 shows an operating environment for the automatic adjustment of lateral control in response to rapid trajectory changes for a vehicle equipped with ADAS according to an exemplary embodiment. Fig. Figure 2 shows a block diagram illustrating a system for automatically adjusting lateral control in response to rapid trajectory changes for a vehicle equipped with ADAS according to an exemplary embodiment. Fig. Figure 3 shows a flowchart illustrating a procedure for automatically adjusting lateral control in response to rapid trajectory changes for an ADAS-equipped vehicle according to another exemplary embodiment. Fig. Figure 4 shows a block diagram illustrating an exemplary implementation of a system for automatically adjusting lateral control in response to rapid trajectory changes for a vehicle equipped with ADAS according to an exemplary embodiment. Fig. Figure 5 shows a flowchart illustrating a method for automatically adjusting the lateral control in response to rapid trajectory changes for an ADAS-equipped vehicle according to another exemplary embodiment.

[0031] The examples shown here illustrate preferred embodiments of the invention, and such examples are not to be understood as limiting the scope of the invention in any way.

[0032] Embodiments of the present disclosure are described herein. However, it should be understood that the disclosed embodiments are merely examples and that other embodiments may take different and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or reduced in size to show details of certain components. Therefore, specific structural and functional details disclosed herein are not to be understood as limiting, but merely representative. The various features shown and described with reference to one of the figures can be combined with features shown in one or more other figures to create embodiments that are not explicitly shown or described. The illustrated combinations of features represent embodiments for typical applications.However, various combinations and modifications of the features that are consistent with the teachings of this revelation may be desirable for certain applications or implementations.

[0033] Fig. Figure 1 schematically shows an operating environment 100 for the use of automatic lateral control adaptation in response to rapid trajectory changes for an ADAS-equipped vehicle according to an exemplary embodiment. The exemplary operating environment 100 comprises a two-lane roadway 105 with a lane center 110, a host vehicle 115, an obstacle 120, an automated adaptation vehicle path 125, and a control vehicle path 130.

[0034] Occasionally, when maneuvers are initiated by an ADAS within a host vehicle, sudden trajectory changes can cause jump inputs to the control system, potentially introducing instability and performance issues. Earlier systems were susceptible to rapid trajectory changes because the vehicle's path might only be calculated every ten milliseconds. When a sudden trajectory change is detected, it can trigger abrupt jump inputs to the control system. These abrupt jump inputs can lead to unstable control behavior during ADAS operations such as LCoD, LCoD abort, and Collision Imminent Steering. Unstable control behavior can result in ADAS disabling and / or an inappropriate or unexpected experience for the vehicle occupants.

[0035] The currently disclosed system and procedure are configured to adapt the control signal in these scenarios to achieve a desired system response. In response to sudden and rapid trajectory changes, which frequently occur during maneuvers such as LCoD and Collision Imminent Steering, the exemplary automated control adaptation is configured to adjust the steering vehicle path 130 to generate the automated adaptation vehicle path 125. Advantageously, the automated adaptation vehicle path 125 improves vehicle stability by reducing steering overshoot and undershoot caused by rapid trajectory changes during vehicle steering control.The automated adaptation vehicle path 125 improves the stability of the control, increases the stability ranges, improves the functional availability of the lateral control functions by adjusting the control signal to improve the performance and driving feel for the lateral control functions and increase the stability ranges and reduce the calibration complexity when calibrating for these maneuvers.

[0036] In the exemplary environment 100, the host vehicle 115 can travel along a vehicle path that coincides with the lane center 110. Upon detection of the obstacle 120 by the vehicle's sensor systems, the ADAS system in the host vehicle is configured to calculate a new vehicle path so that the host vehicle 115 safely avoids the obstacle 120. A control signal is then generated by the ADAS system of the control vehicle systems to follow the new vehicle path. Without adaptation of the control signal, the vehicle may ultimately follow the control vehicle path 130 due to the rapid trajectory changes resulting from the step inputs to the vehicle control systems. The exemplary procedure performs an adaptation to modify the vehicle control signal so that the host vehicle follows the more desirable automated adaptation vehicle path 125.

[0037] The exemplary procedure and system is configured to adapt the control signal during rapid trajectory changes to increase the availability of lateral control functions, improve the stability margins for the vehicle control systems, enhance the system's ability to handle large and rapid trajectory changes, and thereby optimize driver comfort, consistency of functions, and occupant safety. Adapting the control signal improves vehicle stability by reducing steering overshoot and undershoot caused by rapid trajectory changes. This adaptation of the control signal results in a reduction of lateral jerk and lateral acceleration during rapid trajectory changes, such as...This can be achieved at the start of LCoD / LCoD abort maneuvers, reduce control oscillations due to sudden and rapid trajectory changes, increase stability margins, reduce system instability through calibration, and decrease the calibration effort for maneuvers with rapid trajectory changes. Adjusting the control signal can also compensate for the phase lag introduced by rapid trajectory changes.

[0038] In an alternative embodiment, the exemplary automatic lateral control adapts in response to rapid trajectory changes initiated by a vehicle operation, such as LCoD operation and / or LCoD abort operation. For example, the ADAS system may initiate a lane change in response to an LCoD algorithm. A driver may abruptly abort the lane change by requesting a return to the original lane during the maneuver. Alternatively, a driver may initiate an unsafe lane change, and the ADAS control may abruptly steer the vehicle back to the original lane in response to an unsafe condition detected as a result of the lane change. This abrupt change in the vehicle's direction may cause the undesired vehicle path.In response to this undesired vehicle path, the ADAS control system can automatically adjust the vehicle path, steering torque, or similar parameters so that the vehicle follows a desired path.

[0039] In Fig. Figure 2 shows a block diagram illustrating an exemplary implementation of a system 200 for automatically adjusting lateral control in response to rapid trajectory changes for an ADAS-equipped vehicle. The exemplary system 200 serves to generate control data to perform adaptive lane keeping operation for an ADAS-equipped motor vehicle. The exemplary system 200 may include a camera 245, a memory 250 for storing map data, a global positioning system (GPS) 235, an ADAS control unit 220, a driver monitoring system (DMS) 240, a vehicle control unit 230, a throttle control unit 255, a brake control unit 260, and a steering control unit 270.

[0040] The exemplary system 200 can use one or more sensors 245, such as cameras, lidar, or radar, to detect the environment around the host vehicle. The sensors 245 can, for example, be mounted on the front of a vehicle and have a field of view that covers an approaching road surface during ADAS operation. Using image processing techniques, such as edge detection or similar, the ADAS controller 220 or a sensor fusion controller can determine the distance from the host vehicle to an approaching obstacle in the host vehicle's path. The exemplary system can further include a memory 250 for storing map data, including high-resolution map data, and a GPS 235 for determining a vehicle's position.The exemplary system 200 can be configured to combine the information received from the GPS 235, the camera 245 and the memory 250 to estimate the location of the vehicle.

[0041] The ADAS control unit 220 initially receives data from one or more sensors 245, as well as data from the GPS 235 and the vehicle control unit 230, to perform an ADAS operation, such as LCoD or adaptive cruise control. The ADAS control unit 220 first generates an initial vehicle path in response to the sensor data, the location of the host vehicle, the map data, and user input. The ADAS control unit 220 then generates one or more control signals for coupling with the vehicle control unit 230, so that the host vehicle is controlled along the initial vehicle path.

[0042] In this exemplary embodiment, the ADAS control unit 220 is further capable of detecting an object, such as an obstacle, another vehicle, or a static barrier within the original vehicle path. In response to the detection and to avoid a contact event with the object, the ADAS control unit 220 generates an alternative vehicle path to steer the host vehicle so that it avoids the detected object. In response to the alternative vehicle path, the ADAS control unit can generate a steering torque signal, which is coupled to the vehicle control unit 230 or a steering control unit 270 to guide the host vehicle along the alternative vehicle path. The system then compares the steering torque signal with a torque limit and / or a torque rate limit.If the steering torque signal exceeds the torque limit and / or the torque rate limit, the system performs a control adjustment to reduce sudden path changes. This adjustment can be a first-order or second-order adjustment to compensate for the phase lag introduced by rapid path changes and to reduce the likelihood of introducing instability through calibration. The adjusted steering torque signal is then coupled to the vehicle control unit 230 or a steering control unit 270, such as an electronic power steering (EPS) system.

[0043] The vehicle control unit 230 is configured to receive control data from the ADAS control unit 220 and control the movement of the host vehicle in response to this data. The vehicle control unit 230 can generate throttle control signals, which are coupled to the throttle control unit 255 to control the speed of the host vehicle. The vehicle control unit 230 can generate brake control signals, which are coupled to the brake control unit 260 to control the brake application pressure and timing of the host vehicle's brake application. Similarly, the vehicle control unit 230 can generate steering control signals, which are coupled to the steering control unit 270 to control the steering direction and path of the host vehicle.

[0044] In Fig. A flowchart is shown illustrating an exemplary implementation of a procedure 300 for automatically adjusting lateral control in response to rapid trajectory changes for a vehicle equipped with ADAS. The exemplary procedure can initially be initiated during ADAS operation. During ADAS operation 305, the ADAS controller receives sensor data from vehicle sensors to detect moving and stationary objects near the vehicle, as well as map data from a memory and vehicle position data from a GPS sensor or similar. The ADAS controller generates an initial vehicle path in response to the map, position, and sensor data, as well as user input specifying a destination and / or other user preferences or selections.

[0045] During operation, the ADAS controller, which performs the ADAS operation, is able to detect 310 objects within the initial vehicle path. If an object is not detected within the initial vehicle path, the procedure reverts to ADAS operation 305. If an object is detected within the initial vehicle path, the procedure then 315 generates an adapted vehicle path, including a lateral vehicle path. The lateral vehicle path is generated so that the host vehicle avoids the detected object within the initial vehicle path. The adapted vehicle path may also include an adjustment of the vehicle speed, including reducing the vehicle throttle and / or applying the braking systems.

[0046] The ADAS control unit is then configured to generate control signals to steer the host vehicle along the generated lateral path to avoid the detected obstacle. To steer the host vehicle along the generated lateral path, Method 320 can generate a torque signal that is applied to a steering controller to adjust the direction of the host vehicle. The torque signal can be proportional to the steering angle of the host vehicle's steering controller.

[0047] The procedure next compares the generated lateral vehicle path with an actual lateral vehicle path. To compare the generated lateral vehicle path with the actual lateral vehicle path followed by the host vehicle, the procedure 330 can compare a torque signal level with a torque limit and / or a torque rate limit. If the torque signal level does not exceed the torque limit and / or the torque rate limit, the procedure 335 then applies the torque signal to an electronic power steering (EPS) system to adjust the steering angle. The procedure is then configured 340 to control the host vehicle in response to the steering angle and other measured vehicle dynamics, such as lateral acceleration determined by an inertial measurement unit (IMU).

[0048] If the torque signal level exceeds the torque limit and / or the torque rate limit, indicating a possible rapid trajectory change, the method can then perform an adjustment of the torque value in response to the detected torque output. The control adjustment can be a first-order or a second-order adjustment. In an exemplary embodiment, the control adjustment for rapid trajectory changes can receive a lateral position error and a heading angle error to generate an optimized torque command for rapid trajectory changes.

[0049] First-order adaptation can be determined as a response to: Gp(s)=s+zs+pz=ωc1−sin(ϕc)cos(ϕc) z:zero,p:polep=ωc1+sin(ϕc)cos(ϕc)

[0050] Here, ωc is the frequency at maximum phase lead and φc is the maximum phase lag (compensation).

[0051] Second-order adaptation can be determined as a response to:

[0052] Second-order adaptation: G(s)=(s+z1)(s+z2)(s+p1)(s+p2)=s2+2ζωzs+ωz2s2+2ζωps+ωp2 ωz=ωc(−ζtan(ϕm)+ζ2tan2ϕm+1) ωp=ωc(ζtan(ϕm)+ζ2tan2ϕm+1)

[0053] Here, ωc is the frequency at maximum phase lead and φc is the maximum phase lag (compensation), and ζ is the damping ratio.

[0054] After the adjustment, the adapted torque signal level is then compared with the torque limit and / or the torque rate limit 330. If the torque limit and / or the torque rate limit is exceeded, the adapted torque signal level is further adjusted 325. If the torque limit and / or the torque rate limit is not exceeded, the adapted torque signal level 335 is applied to the EPS and the ADAS controller is further configured to 340 control the host vehicle and return to ADAS operation 305.

[0055] In Fig. Figure 4 shows a block diagram illustrating an exemplary implementation of a system 400 for automatically adjusting the lateral control in response to rapid trajectory changes for a vehicle equipped with ADAS. The exemplary system 400 may include a sensor 410, a processor 420, a vehicle control unit 430, a lateral control unit 440, and a steering control unit 450.

[0056] Sensor 410 is configured to detect objects within a field of view covering a vehicle's path. Sensor 410 can consist of one or more forward-facing cameras positioned at various points on the host vehicle, each with a field of view covering an approaching lane. Image processing techniques can be used to generate a three-dimensional depth map in response to one or more images captured by each camera. This depth map can then be coupled with Processor 420 to detect an object within the lane. Alternatively, the sensor can be a lidar, radar, infrared depth sensor, or another suitable distance-measuring sensor.

[0057] The 420 processor is initially configured to detect the object within the vehicle's path. The object can be detected by comparing it to a depth map or other indicator of nearby objects stored in memory or the like. In response to the object detection, the 420 processor then generates a second vehicle path, which avoids the object. The 420 processor can further be configured to generate an initial steering torque in response to the second vehicle path and to adjust this initial steering torque if it exceeds a torque limit and / or torque rate limit.

[0058] The vehicle controller 430 is configured to control a host vehicle steering system so that it follows the second vehicle signal path in response to the initial steering torque and the adjusted steering torque. In an exemplary embodiment, the initial steering torque can be generated by a lateral controller 440 in response to a lateral vehicle position and a vehicle heading error, which are determined in response to additional vehicle sensors and vehicle control signals received by the vehicle controller. In this embodiment, the processor 420 is configured to generate the second vehicle path, couple this second vehicle path to the vehicle controller 430, and the vehicle controller 430 generates control signals that are coupled to a lateral controller 440 and a longitudinal controller.The lateral control unit 440 couples lateral control signals to the steering control unit 450 and monitors the behavior of the host vehicle. It then performs adjustments to generate adapted lateral control, which may include, for example, adapted steering torque to control the steering torque so that the second vehicle path is accurately followed by the host vehicle. In one example, the adapted steering torque could be coupled with an electronic power steering system to control the rate of change of a steering angle.

[0059] Optionally, in this exemplary embodiment, the adaptation can be a first-order adjustment in response to a frequency at maximum phase lead and maximum phase lag of the initial steering torque. Alternatively, the adaptation can be a second-order adjustment in response to a damping ratio, a frequency at maximum phase lead and maximum phase lag of the initial steering torque. The adapted steering torque can be an optimized torque command for a rapid path change, with the adaptation compensating for a phase lag introduced by the rapid path change.

[0060] In an exemplary embodiment of an adaptive driving assistance system for implementing an adaptive driving assistance algorithm in a host vehicle, the exemplary system comprises a first sensor 410, a second sensor, an ADAS processor 420, a vehicle controller 430, and a steering controller 450. The first sensor is configured to generate a depth map of a field of view, the field of view covering a current vehicle path. A second sensor, e.g., an IMU 435, can be configured to determine a host vehicle speed and / or host vehicle accelerations. The processor can further be configured to detect an object within the field of view in response to the depth map. The processor can then generate a vehicle path so that the host vehicle avoids the object. The processor 420 can then couple this vehicle path to a vehicle controller 430.

[0061] The vehicle control unit 430 can then be configured to generate an initial steering torque in response to the vehicle's path, couple the initial steering torque to the steering control unit, and compare the initial steering torque to a torque limit and / or a torque rate limit. The vehicle control unit 430 can then generate an adjusted steering torque in response to the vehicle speed and the initial steering torque, which exceeds the torque limit and / or the torque rate limit. The steering control unit 450 is configured to adjust a host vehicle steering angle in response to the initial steering torque and the adjusted steering torque. In an exemplary embodiment, the steering control unit is part of an electronic power steering system.

[0062] In Fig.Figure 5 is a flowchart illustrating an exemplary implementation of a procedure 500 for automatically adjusting the lateral control in response to rapid trajectory changes for a vehicle equipped with ADAS. A procedure 510 first serves to detect a rapid trajectory change of the host vehicle or host vehicle steering controls. In one example, the rapid trajectory change can be detected using an IMU. Alternatively, the rapid trajectory change can be detected in response to signals or depth maps generated by one or more vehicle sensors indicating the presence of an object within the initial vehicle path. In one example, the sensor can be a camera, with the object being detected using image processing techniques. Alternatively, the sensor can be a lidar, with the object being detected in response to a depth map generated by the lidar.In one exemplary embodiment, the rapid trajectory change can be detected in response to signals generated by one or more sensors indicating a change in the desired vehicle trajectory. For example, the method can detect a rapid trajectory change in response to a measured jump in the error signals fed into the vehicle control system. These error signals can be calculated using a combination of front camera, map, and IMU data, or they can use GPS data or data received via vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2I) communication.

[0063] The procedure next generates a second vehicle path in response to the rapid trajectory change. The processor can be an ADAS processor, a digital signal processor, a microcontroller, or a combination thereof. The procedure next generates an initial steering torque in response to the second vehicle path; the initial steering torque is generated by a lateral controller in response to a lateral vehicle position and a vehicle course error.

[0064] In this exemplary embodiment, method 535 compares the initial steering torque with a torque limit and / or a torque rate limit. The torque limit and / or the torque rate limit may indicate a change in the steering direction that could be uncomfortable for the vehicle occupants or cause unstable vehicle behavior. The steering torque limit has a variable threshold that depends on other operating conditions of the vehicle, such as vehicle speed, road conditions, and the like. The method next performs an adjustment 540 on the initial steering torque to generate an adjusted steering torque in response to the initial steering torque exceeding a torque limit and / or a torque rate limit.The adaptation can be a first-order adjustment in response to a frequency at maximum phase lead and maximum phase lag of the initial steering torque. Alternatively, the adaptation can be a second-order adjustment responding to a damping ratio, a frequency at maximum phase lead, and maximum phase lag of the initial steering torque. The adapted steering torque can be an optimized torque command for a rapid path change to compensate for a phase lag introduced by the rapid path change.

[0065] Finally, the method is configured to use a vehicle controller to control a host vehicle steering system so that it follows the second vehicle signal path in response to the adapted steering torque. In one example, the vehicle controller is a lateral controller configured to control a steering angle of the host vehicle. In another embodiment, the adapted steering torque can be coupled with an electronic power steering system to control a rate of change of a steering angle.

Claims

[1] An adaptive driver assistance device comprising the following: a sensor (245, 410) configured to detect an object within a first vehicle path; a processor (420) configured to generate a second vehicle path in response to the detection of the object, such that the second vehicle path avoids the object, the processor further configured to generate an initial steering torque in response to the second vehicle path in order to adapt the initial steering torque in order to generate an adapted steering torque in response to the initial steering torque exceeding a torque limit; and a vehicle control unit for controlling a host vehicle steering system to follow the second vehicle signal path in response to the adapted steering torque; where the adaptation is a first-order adaptation in response to a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque, or where the adjustment is a second-order adjustment in response to a damping ratio, a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque. [2] The adaptive driving assistance device according to claim 1, wherein the initial steering torque is generated by a lateral controller in response to a lateral vehicle position and a vehicle course error. [3] The adaptive driving assistance device according to claim 1, wherein the torque limit is a torque rate limit. [4] The adaptive driving assistance device according to claim 1, wherein the sensor (245, 410) is a lidar and wherein the object is detected in response to a depth map generated by the lidar. [5] The adaptive driving assistance device according to claim 1, wherein the adapted steering torque is an optimized torque command for a rapid trajectory change. [6] The adaptive driving assistance device according to claim 1, wherein the adaptation compensates for a phase lag introduced by a rapid change in trajectory path. [7] The adaptive driving assistance device according to claim 1, wherein the adapted steering torque is coupled with an electronic power steering system to control a rate of change of a steering angle. [8] A method (500) comprising the following: (510) Detection, by means of a sensor, of a rapid path displacement from a first vehicle path; (520) Generating, by a processor, a second vehicle path in response to the detection of rapid path shift; (530) Generating, by the processor, an initial steering torque in response to the second vehicle path; (540) Performing, by the processor, an adjustment to the initial steering torque in order to generate an adjusted steering torque in response to the initial steering torque exceeding a torque limit; and Control, by a vehicle control unit, a host vehicle steering system, to follow the second vehicle signal path in response to the adapted steering torque; where the adaptation is a first-order adaptation in response to a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque, or where the adjustment is a second-order adjustment in response to a damping ratio, a frequency at a maximum phase lead and a maximum phase lag of the initial steering torque.

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