Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
  • B60W30/18—Propelling the vehicle
  • B60W30/18009—Propelling the vehicle related to particular drive situations
  • B60W30/18145—Cornering
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
  • B60W40/02—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to ambient conditions
  • B60W40/06—Road conditions
  • B60W40/072—Curvature of the road
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W50/00—Details of control systems for road vehicle drive control not related to the control of a particular sub-unit, e.g. process diagnostic or vehicle driver interfaces
  • B60W50/0097—Predicting future conditions
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V20/00—Scenes; Scene-specific elements
  • G06V20/50—Context or environment of the image
  • G06V20/56—Context or environment of the image exterior to a vehicle by using sensors mounted on the vehicle
  • G06V20/588—Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2540/00—Input parameters relating to occupants
  • B60W2540/18—Steering angle
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2552/00—Input parameters relating to infrastructure
  • B60W2552/30—Road curve radius
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2552/00—Input parameters relating to infrastructure
  • B60W2552/53—Road markings, e.g. lane marker or crosswalk
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2710/00—Output or target parameters relating to a particular sub-units
  • B60W2710/20—Steering systems
  • B60W2710/205—Steering speed
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2710/00—Output or target parameters relating to a particular sub-units
  • B60W2710/20—Steering systems
  • B60W2710/207—Steering angle of wheels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2720/00—Output or target parameters relating to overall vehicle dynamics
  • B60W2720/10—Longitudinal speed
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
  • B60Y2300/00—Purposes or special features of road vehicle drive control systems
  • B60Y2300/18—Propelling the vehicle
  • B60Y2300/18008—Propelling the vehicle related to particular drive situations
  • B60Y2300/1815—Cornering

Definitions

• the present invention relates to a method for operating a vehicle, a computer program, a control system and a vehicle with such a control system.
• Modern vehicles such as passenger vehicles, are nowadays usually equipped with several driver assistant systems.
• Examples are systems for adapted cruise control (ACC), lane keeping assistance (LKA), highway assistance (HWA), traffic jam assistance (TJA) and traffic jam pilot (TJP).
• ACC adapted cruise control
• LKA lane keeping assistance
• HWA highway assistance
• TJA traffic jam assistance
• TJP traffic jam pilot
• a crucial aspect of these systems is a curvature control. This includes an anticipation of a curvature of an approaching curve and a correspondingly adapted velocity.
• the curvature of a road is determined based on lane markings detected by a camera of the vehicle. If no lane markings are present on the road or if the quality in the image data representing the lane markings is poor, a current path determined from odometry data is used instead.
• WO 2020 / 001346 A1 proposes to acquire current steering wheel angle information of the vehicle if no road surface marker is identified from a road surface image.
• a method for operating a vehicle comprises the steps: receiving sensor data of a sensor system of the vehicle, the sensor data including a current steering-angle 5 and steering-angle velocity W of the vehicle driving on a road with a curve, determining a radius ahead RA of the curve at a position ahead P2 that the vehicle will reach in a predetermined time span T based on an odometry-based radius ahead Ro given by the equation:
• R o R c - T [ (L ⁇ W) / (sin 2 (6) ] , wherein 6 is the steering-angle, W is the steering-angle velocity, L is a distance between the front and rear wheels of the vehicle and Rc is a radius of the road at the current position of the vehicle, and performing a curvature control function based on the determined radius ahead RA.
• the radius RA of a curvature of a curve of the road on which the vehicle is driving is determined based on sensor data of a steering-angle sensor of the vehicle, in particular based on the measured current steering-angle and steering-angle velocity of the vehicle.
• the curvature of the road on which the vehicle is driving is determined based on odometry data. This allows a better anticipation of the curvature.
• the curvature of the road can be determined also in the case that no lane markings are present on the road and/or detected in image data of a camera of the vehicle. A better anticipation of the curvature of the road allows a better curvature control of the vehicle. In particular, a control of advanced braking before and/or during entering a curve can be improved, thus increasing safety and comfort of vehicle passengers.
• the predetermined time span T can for example be a or any value within the range of 0.5 to 2.5 seconds.
• the predetermined time span T can, for example, have a value of or of about 0.5 seconds, 1 second, 1 .5 seconds, 2 seconds, or 2.5 seconds .
• the steering-angle is, for example, a rotation angle of a steering shaft of the vehicle.
• the steering-angle is, for example, an angle of one or more driving wheels of the vehicle.
• the steering-angle velocity is, for example, a first derivative with respect to time of the steeringangle.
• the road on which the vehicle is driving includes, for example, one or more lanes. There can be lane markings limiting the lane(s), thus marked lanes. In another case, for example, no lane markings for the one or more lanes are present, thus unmarked lanes.
• the vehicle is, for example, driving on one of the (e.g. marked or unmarked) lanes of the road.
• the curve of the road is, for example, a curve of a (e.g. marked or unmarked) lane on which the vehicle is driving.
• the radius of a curvature of the road is, for example, a radius of a curvature of the (e.g. marked or unmarked) lane on which the vehicle is driving.
• the sensor system includes, in particular, a steering-angle sensor unit.
• the steering-angle sensor unit is, for example, based on a magnetoresistance technology such as a Giant Magnetoresistance technology (GMR element).
• GMR element Giant Magnetoresistance technology
• the steering-angle sensor is, for example, fixed on a steering shaft of the vehicle.
• a hub gear wheel of the sensor is, for example, transmitting the rotary movement of the shaft to two measuring gear wheels.
• a magnet is mounted, whose field changes its direction in accordance with the rotational movement.
• a GMR sensor element may be located to detect the angle position of the magnet above.
• the analog values of the GMR elements are, for example, converted into digital information.
• the steering-angle sensor provides, for example, an absolute steering-angle value over the complete steering-angle range.
• the sensor system of the vehicle includes, for example, further sensor units such as one or more environmental sensor units.
• the environmental sensor units are configured to detect a driving state of the vehicle and/or an environment of the vehicle. Examples of such sensor units are a camera device for capturing images of the surrounding, a radar device (radio detection and ranging) for obtaining radar data and a lidar device (light detection and ranging) for obtaining lidar data.
• the sensor system may in addition include ultrasonic sensors, location sensors, rain sensors, temperature sensors and/or light sensors.
• the sensor units of the vehicle are each configured to output a sensor signal, for example to a driving assistance system or a parking assistance system, which for example performs assisted or (semi-)autonomous driving as a function of the detected sensor signals.
• the sensor units can each be configured to output a sensor signal to the control system and/or a curvature control system/unit, which performs curvature control as a function of the detected sensor signals.
• the method steps are, in particular, carried out by a control system of the vehicle.
• a nominal velocity V A of the vehicle at the position ahead is determined based on the determined radius ahead RA and a predetermined maximum lateral acceleration AMAX by the equation:
• V A (AMAX ⁇ RA) 1/2 .
• the curvature control function is performed based on the determined nominal velocity V A .
• the curvature control of the vehicle can be performed such that the velocity of the vehicle at the position ahead is equal (or below) the calculated nominal velocity. Hence, it can be avoided that the vehicle is pulling and/or braking out of the curve.
• the maximum lateral acceleration AMAX has, for example, a or any value between 2.5 m/s 2 and 3.5 m/s 2 .
• the maximum lateral acceleration AMAX can have, for example, a value of or of about 2.5 m/s 2 , 3 m/s 2 or 3.5 m/s 2 , 2 m/s 2 or smaller, 2.5 m/s 2 or smaller or 3 m/s 2 or smaller.
• the value of the maximum lateral acceleration A AX depends on the velocity of the vehicle.
• an expected acceleration of the vehicle at the position ahead is determined based on a current velocity V c of the vehicle and a nominal velocity V A of the vehicle at the position ahead. Further, a presence of lane markings of the road is detected and a track quality of the detected lane markings is determined based on the sensor data, and a lane-based radius ahead RL of the curve at the position ahead is determined based on the detected lane markings.
• the curvature control function is performed based on the odometry-based radius ahead Ro and the lane-based radius ahead RL such that: the radius ahead RA is set equal to the minimum of the lane-based radius ahead RL and the odometry-based radius ahead Ro when the determined track quality is above a predetermined track quality threshold and the determined expected acceleration corresponds to a braking of the vehicle, the radius ahead RA is set equal to the maximum of the lane-based radius ahead RL and the odometry-based radius ahead Ro when the determined track quality is above the predetermined track quality threshold and the determined expected acceleration corresponds to a positive acceleration of the vehicle, and the radius ahead RA is set equal to the odometry-based radius ahead Ro when the determined track quality is at or below the predetermined track quality threshold.
• the radius ahead RA of the curve of the road on which the vehicle is driving can be advantageously determined based on the odometry- based radius ahead Ro alone.
• the radius ahead RA of the curve of the road on which the vehicle is driving can be advantageously set equal to either the lane-based radius ahead RL or the odometry-based radius ahead Ro depending on the acceleration state (braking or positive acceleration) of the vehicle.
• the current velocity Vc of the vehicle is the velocity of the vehicle at the current position.
• the sensor system of the vehicle includes, in particular, one or more camera devices for capturing images of the surrounding of the vehicle. Further, the presence or absence of lane markings of the road is detected based on image data (as an example of sensor data) of the one or more camera devices of the vehicle.
• the camera device(s) include, for example, a front camera arranged at the front windscreen of the vehicle and configured to monitor an area in front of the vehicle. However, the one or more camera devices may also be arranged at a different window of the vehicle and/or monitor a different area, e.g., at the sides or behind the vehicle.
• Determining the track quality of the detected lane markings includes, for example, determining a level of the current track quality of the detected lane markings.
• the track quality (level) of the detected lane markings corresponds, for example, to an image quality of the image data provided by the one or more camera devices.
• a level of the track quality of the detected lane markings and/or a level of the image quality of the image data provided by the one or more camera devices is, for example, determined and provided by the one or more camera devices.
• the predetermined track quality threshold is, for example, a predetermined threshold of the track quality level.
• the method includes the step of determining an error ARL of the determined lane-based radius ahead RL.
• the error AR L is, for example, a measure of the track quality of the detected lane markings.
• the curvature control function may be per- formed based on the odometry-based radius ahead Ro and the lane-based radius ahead RL such that: the radius ahead RA is set equal to the minimum of the lane-based radius ahead RL and the odometry-based radius ahead Ro when the determined error AR L is below a predetermined threshold and the determined expected acceleration corresponds to a braking of the vehicle, the radius ahead RA is set equal to the maximum of the lane-based radius ahead RL and the odometry-based radius ahead Ro when the determined error AR L is below the predetermined threshold and the determined expected acceleration corresponds to a positive acceleration, and the radius ahead RA is set equal to the odometry-based radius ahead Ro when the determined error AR L is equal to or above the predetermined threshold.
• the radius ahead RA of the curve of the road on which the vehicle is driving can be advantageously determined based on the odometry- based radius ahead Ro alone.
• the radius ahead RA of the curve of the road on which the vehicle is driving can be advantageously set equal to either the lane-based radius ahead RL or the odometry-based radius ahead Ro depending on the acceleration state (braking or positive acceleration) of the vehicle.
• the lane-based radius ahead RL is determined by the equation:
• RL 1 / [ (6 a T) + (2 b) ], wherein a and b are the first two coefficients of a polynomial and T is the predetermined time span.
• the polynomial is, in particular, a polynomial function.
• the polynomial is, in particular, mathematically representing a perceived lane.
• the polynomial is, for example, a third-degree or higher-order polynomial function. For example, the lane-based radius ahead RL is determined based on the first two coefficients a and b of the third-degree polynomial:
• curvature ahead can be expressed as:
• radius ahead R is given by:
• performing the curvature control function includes controlling an acceleration and/or a jerk of the vehicle based on a current velocity V c of the vehicle at a current position and a nominal velocity V A of the vehicle at the position ahead.
• the jerk of the vehicle describes, in particular, the variation of the acceleration of the vehicle with time.
• the jerk of the vehicle is, in particular, the first derivative with respect to time of the acceleration of the vehicle and the second derivative with respect to time of the velocity of the vehicle.
• the jerk of the vehicle includes, for example, a longitudinal jerk. In other examples, the jerk of the vehicle may also include, for example, a lateral jerk.
• the jerk of the vehicle is, for example, controlled based on a difference of the current velocity V c of the vehicle and the nominal velocity V A of the vehicle at the position ahead.
• controlling the acceleration and/or the jerk of the vehicle includes a proportional and/or derivative controlling of the acceleration and/or the jerk, and the nominal velocity V A of the vehicle at the position ahead is a setpoint in the proportional and/or derivative controlling and the current velocity V c of the vehicle is a process variable of the proportional and/or derivative controlling.
• the jerk is controlled such that the current velocity Vc of the vehicle is driven towards the nominal velocity V A , the nominal velocity V A being the setpoint of the controller, i.e. the desired value for the velocity of the vehicle at the position ahead.
• control system includes a proportional controller, a derivative controller and/or a proportional derivative controller.
• a proportional derivative controller (PD controller) is a combined proportional and derivative controller, i.e. a proportional plus a derivative controller.
• a proportional controller is a type of controller in which an output of the controller varies in proportion with an input (e.g., an error signal) of the controller.
• a derivative controller is a type of controller in which an output of the controller is proportional to a rate with which an error signal is changing with time.
• the error signal is, for example, the error between a setpoint (here: the nominal velocity V A of the vehicle at the position ahead) and a measurement of the process variable (here: the current velocity V c of the vehicle).
• performing the curvature control function includes determining a first time phase of negative jerk, a second time phase of zero jerk and a third time phase of positive jerk based on a current velocity V c of the vehicle at a current position and on a nominal velocity V A of the vehicle at the position ahead, said first, second and third time phases being continuous with each other.
• the curvature control function can be better performed.
• the first time phase is, for example, a time phase before and/or during the vehicle entering the curve of the road with negative acceleration (braking).
• the second time phase is, for example, a time phase of driving within the curve with constant acceleration.
• the third time phase is, for example, a time phase of still negative acceleration but with positive jerk (i.e., still braking but decreasing braking).
• the first, second and third time phases are, for example, determined by means of a state machine of the control system.
• performing the curvature control function includes determining a fourth time phase of zero jerk and zero acceleration (i.e., constant speed) and/or a fifth time phase of positive jerk and positive acceleration.
• the fourth and fifth time phases are, in particular, continuous with the first to third time phases such that the fourth time phase is continuous with the third time phase and the fifth time phase is continuous with the fourth time phase (or if no fourth time phase is present, with the third time phase).
• performing the curvature control function includes controlling an acceleration of the vehicle to be below a predetermined acceleration threshold and/or controlling a jerk of the vehicle to be below a predetermined jerk threshold.
• the vehicle is controlled such that a maximum jerk (e.g., maximum longitudinal jerk) of the vehicle is limited. Hence, a safety and comfort of the driver (and other passengers) can be increased.
• a longitudinal jerk of the vehicle is controlled to be below a predetermined longitudinal jerk threshold.
• a computer program comprises instructions which, when the program is executed by a computer, cause the computer to carry out the above-described method.
• a computer program such as a computer program means, may be embodied as a memory card, USB stick, CD-ROM, DVD or as a file which may be downloaded from a server in a network.
• a file may be provided by transferring the file comprising the computer program product from a wireless communication network.
• a control system for a vehicle is provided.
• the control system is configured to perform the above-described method.
• a vehicle with an above-described control system is provided.
• the respective above or below described entities may be implemented in hardware and/or in software. If said entity is implemented in hardware, it may be embodied as a device, e.g. as a computer or as a processor or as a part of a system, e.g. a computer system. If said entity is implemented in software it may be embodied as a computer program product, as a function, as a routine, as an algorithm, as a program code, part of a program code or as an executable object.
• each of the entities mentioned above can also be designed as part of a higher-level control system of the vehicle, such as a central electronic control unit (ECU).
• ECU central electronic control unit
• Fig. 1 shows a top view of a vehicle according to an embodiment
• Fig. 2 shows the vehicle of Fig. 1 on a road
• Fig. 3 illustrates a steering-angle of the vehicle of Fig. 1 ;
• Fig. 4 shows a view similar as Fig. 2, wherein the road comprises lane markings;
• Fig. 5 shows a data point of a determined lane-based radius of a curve of the road of
• Fig. 6 shows a timely evolution of an acceleration and a jerk of the vehicle of Fig. 1 when driving through a curve of the road shown in Fig. 2 or 4;
• Fig. 7 shows a control system of the vehicle of Fig. 1 ;
• Fig. 8 shows a flowchart illustrating a method for operating the vehicle of Fig. 1 .
• Fig. 1 shows a schematic top view of a vehicle 1 .
• the vehicle 1 is, for example, a passenger vehicle.
• the vehicle 1 may also be another kind of vehicle such as a van or truck.
• the vehicle 1 comprises a control system 2 for controlling the vehicle 1 .
• the vehicle 1 comprises a sensor system 3 including several environmental sensor units 4, 5, 6, 7 arranged at the vehicle 1 .
• the sensor system 3 comprise, in particular, one or more camera devices 4 such as one or more front camera devices.
• the camera devices 4 are configured for obtaining image data I of a surrounding 8 of the vehicle 1 and for sending the image data or results of an image analysis of the image data to the control system 2.
• the front camera device 4 is attached to a front windscreen 9 of the vehicle 1 .
• the sensor system 3 further comprise, for example, one or more radar devices 5 for obtaining radar data of the surrounding 8 of the vehicle 1 .
• the sensor system 3 may further comprise, for example, one or more lidar devices 6 for obtaining lidar data of the surrounding 8 of the vehicle 1 .
• the sensor system 3 further comprises a steering-angle sensor 10 arranged at a steering shaft 11 of the vehicle 1 .
• the steering shaft 11 is connected to a steering wheel 12 of the vehicle 1 .
• the steering-angle sensor 10 is configured to measure a steering-angle 5 (Fig. 3) and a steering-angle velocity W of the vehicle 1 .
• the sensor system 3 may comprise further sensors such as ultrasonic sensors 7, one or more rain sensors and/or one or more light sensors (not shown).
• a method for operating the vehicle 1 will be described with reference to Figs. 2 to 8.
• the method is, in particular, a method for performing a curvature control of the vehicle 1 to smoothly drive the vehicle 1 into and out of a curve 13 of a road 14 (Fig. 2).
• Fig. 2 shows the vehicle 1 of Fig. 1 on the road 14 comprising the curve 13.
• the vehicle 1 is shown in Fig. 2 on a first position P1 (current position) before entering the curve 13.
• the vehicle 1 is driving at the current position P1 with a current velocity Vc.
• the vehicle 1 is shown in Fig. 2 with dashed lines on a second position P2, where the vehicle 1 has entered the curve 13.
• the second position P2 is ahead of the first position P1 with respect to a driving direction 15 of the vehicle 1 .
• the control system 2 of the vehicle 1 receives sensor data S (Fig. 7) of the sensor system 3 (Fig. 1 ) of the vehicle 1 .
• the sensor data S include odometry data of the steering-angle sensor 10 (Fig. 1 ), in particular a current steering-angle 5 and a current steering-angle velocity W of the vehicle 1 .
• the sensor data S include image data I of the camera device(s) 4 (Fig. 1 ) of the vehicle 1 .
• the control system 2 comprises, for example, a receiving unit 16 (Fig. 7) for receiving the sensor data S from the sensor system 3.
• the control system 2 determines a radius ahead Ro of the curve 13 at the position ahead P2 based on the odometry data (5, w).
• the position ahead P2 is, in particular, a position that the vehicle 1 will reach in a predetermined time span T (e.g., 1 second or 2 seconds).
• the control system 2 comprises, for example, a first determining unit 20 (Fig. 7) for determining the odometry-based radius ahead Ro-
• the odometry-based radius ahead Ro is determined based on the following relations.
• L is a distance between front wheels 17 and rear wheels 18 (Fig. 3) of the vehicle 1 .
• the control system 2 determines - in the case that lane markings 19 (Fig. 4) of the road 14' on which the vehicle 1 is driving are detected in the image data I - a lane-based radius ahead RL of the curve 13' at the position ahead P2.
• the control system 2 comprises, for example, a second determining unit 21 (Fig. 7) for determining the lane-based radius ahead RL.
• a track quality (e.g., a level of a track quality) of the detected lane markings 19 are determined.
• the track quality (e.g., the track quality level) corresponds, in particular, to an image quality of the image data I received by the camera device(s) 4 and/or a detection quality of the lane markings 19 in the image data I.
• the track quality (e.g., track quality level) is, for example, determined and/or provided by the camera device(s) 4.
• the track quality (e.g., the track quality level) may also be determined by the second determining unit 21 (Fig. 7) of the control system 2.
• an error AR L (Fig. 5) of the lane-based radius ahead RL may be determined based on the detected lane markings 19.
• the error AR L may, in particular, be used as a measure of the track quality (e.g., a measure of the track quality level) of the detected lane markings 19.
• the lane-based radius ahead RL is determined by the equation
• T is the predetermined time span of step S2.
• a radius ahead RA to be used in a curvature control function.
• the radius ahead RA is determined based on the odom- etry-based radius ahead Redetermined in step S2 and on the lane-based radius ahead RL determined in step S3.
• an arbitration i.e., decision between the determined odometry-based radius ahead Ro and the determined lane-based radius ahead Ri is performed based on the determined track quality of the detected lane markings 19 (e.g., based on the determined track quality level of the detecting the lane markings 19 and/or based on the determined error AR L of the lane-based radius ahead RL) and based on an expected acceleration A A (Fig. 4) of the vehicle 1 at the position ahead P2.
• the control system 2 comprises, for example, an arbitration unit 22 (Fig. 7) for determining the radius ahead RA based on the odometry-based radius ahead Ro and on the lane-based radius ahead RL.
• the radius ahead RA is set equal to the odometry-based radius ahead Ro-
• the radius ahead RA is set equal to the minimum of the lane-based radius ahead RL and the odometry-based radius ahead Ro-
• the radius ahead RA is set equal to the maximum of the lane-based radius ahead RL and the odometry-based radius ahead Ro-
• the track quality may also be estimated based on determining an error AR of the lane-based radius ahead RL, as illustrated in Fig. 5.
• Fig. 5 shows a data point 23 of the determined lane-based radius ahead RL in a radius-position diagram together with an error bar 24 corresponding to the determined error ARL.
• a predetermined threshold Rth for the error ARLof the lane-based radius ahead RL.
• the determined error ARL is smaller than the predetermined threshold Rth.
• the error AR can also be larger than the predetermined threshold Rth.
• the radius ahead RA is set equal to the odometry-based radius ahead Ro.
• the radius ahead RA is set equal to the minimum of the lane-based radius ahead RL and the odometry-based radius ahead Ro-
• the radius ahead RA is set equal to the maximum of the lane-based radius ahead RL and the odometry- based radius ahead Ro-
• a nominal velocity VA (Fig. 2) at the position ahead P2 based on the determined radius ahead RA and a predetermined maximum lateral acceleration A AX by the equation:
• V A (AMAX ⁇ RA) 1/2 .
• the control system 2 comprises, for example, a third determining unit 25 (Fig. 7) for determining the nominal velocity VA.
• control system 2 performs a curvature control function based on the determined nominal velocity V A corresponding to the determined radius ahead RA Of the curve 13, 13' at the position ahead P2.
• the control system 2 comprises, for example, a curvature control unit 26 (Fig. 7) for performing the curvature control function.
• a curvature control unit 26 for performing the curvature control function.
• an acceleration A(t) and a jerk J(t) (Fig. 6) of the vehicle 1 are controlled such that the current velocity Vc (Fig. 2) of the vehicle 1 is changed towards the nominal velocity VAOf the vehicle 1 in a suitable manner.
• the curvature control unit 26 comprises a proportional derivative control unit 27 (PD-control unit 27).
• the nominal velocity V A of the vehicle 1 at the position ahead P2 is a setpoint 28 of the PD-control unit 27.
• the current velocity Vc of the vehicle 1 is a process variable 29 of the PD-control unit 27.
• the PD-control unit 27 performs, in particular, a control based on a difference of the current velocity Vc and the nominal velocity VA.
• the curvature control unit 26 further comprises a fourth determining unit 28 for determining time phases T 1 T2, T3, T4, T5 of acceleration A(t) and jerk J(t) (Fig. 6).
• the fourth determin- ing unit 28 includes, for example, a state machine or another logic unit for determining the time phases T1 , T2, T3, T4, T5.
• Fig. 6 shows in an upper panel a timely evolution of an acceleration A(t) of the vehicle 1 driving through the curve 13 (Fig. 2). Further, in a lower panel of Fig. 6, a timely evolution of a jerk J(t) of the vehicle 1 is shown.
• the jerk J(t) is the first derivative with respect to time of the acceleration A(t). That means, the jerk indicates a timely variation of the acceleration A(t).
• a first time phase T 1 of negative acceleration (braking) and negative jerk (increasing braking) is determined, the first time phase T1 corresponding, for example, to a state in which and/or before the vehicle 1 enters the curve 13 (Fig. 2).
• a second time phase T2 of constant negative acceleration (constant braking) and zero jerk is determined, the second time phase T2 corresponding, for example, to a state in which the vehicle 1 is driving within the curve 13.
• a third time phase T3 of negative acceleration (still braking) but positive jerk (decreasing braking) is determined, third time phase T3 being, for example, a time phase of (preparing) driving, when inside the curve 13, the current velocity V c is getting close to the nominal velocity V A .
• a fourth time phase T4 of zero jerk and zero acceleration is determined.
• the third and fourth time phases T3, T4 may be called "release and constant speed phases”.
• a fifth time phase T5 of positive jerk and positive acceleration is determined.
• the time phases T1 , T2, T3, T4 and T5 are continuous with each other, as shown in Fig. 5.
• the curvature control unit 26 further comprises a limitation unit 29 (Fig. 7) for limiting the acceleration A and/or the jerk J (Fig. 6) of the vehicle 1 .
• the curvature control function is performed such that the acceleration A (i.e. an absolute value of the acceleration A) of the vehicle 1 is below a predetermined acceleration threshold A th .
• the curvature control function is performed such that the jerk J (i.e. an absolute value of the jerk) of the vehicle 1 is below a predetermined jerk threshold J th .
• the radius ahead RA of the curvature of the curve 13 of the road 14 on which the vehicle 1 is driving (Fig. 2) is anticipated based on odometry data (5, w, Fig.
• a nominal velocity V A as a desired velocity at the position ahead P2 is calculated.
• a curvature control is performed such that in the process of realizing the nominal velocity V A , braking and positive acceleration as well as the jerk are limited (Fig. 6) to values that ensure the safety and comfort of the driver and other passengers of the vehicle 1 .

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• 2021
  • 2021-12-10 DE DE102021132711.3A patent/DE102021132711A1/de active Pending
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