Automatic driving method, acceleration curve generating device and recording medium

Abstract

The present application relates to an automatic driving method, an acceleration curve generating device and a recording medium. A method for driving a vehicle on a curve, comprising: a processor detecting a curve in front of the vehicle and having a curvature equal to or greater than a threshold; the processor calculating a target acceleration for entering the curve; the processor generating a driving mode using the magnitude of the target acceleration; the processor calculating an acceleration curve based on the driving mode; the processor outputting a control torque based on the acceleration curve and controlling the vehicle.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0100312, filed on August 16, 2019, which is hereby incorporated by reference herein in its entirety. Technical Field

[0003] The present disclosure relates to an apparatus for generating an acceleration curve and a method for automatically driving on a road using the apparatus. Background Art

[0004] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0005] Currently, commercially available autonomous driving vehicles apply advanced driver assistance systems (ADAS) to free drivers from simple operations such as manipulating a steering wheel and pedals while the vehicle is traveling and also to prevent accidents due to driver carelessness, and therefore have recently attracted more attention.

[0006] However, we have found that general ADAS has not been combined with dynamic factors indicating the overall longitudinal and lateral motions of the vehicle, and is only limitedly capable of quantitatively calculating control values ​​defined by associating the longitudinal and lateral motions, and therefore, the behavior of the vehicle is tricky depending on the road environment. Specifically, sudden braking, sudden turning, and sudden acceleration occur when the vehicle travels along a curve, and the behavior of the vehicle on the curve changes according to the flow of deceleration, turning, and deceleration, which is a factor that increases the discomfort of passengers riding in the vehicle, such as Figure 1A and Figure 1B shown.

[0007] Figure 1A and Figure 1B The figure is used to explain the discomfort felt by passengers when the vehicle is traveling on a curve using ADAS installed in a general autonomous driving vehicle. Figure 1A is a diagram showing an acceleration vector of a vehicle exhibited according to a flow rate of rapid braking, sudden turning, and sudden acceleration when the vehicle travels on a curve. Figure 1B This is a diagram that qualitatively shows the change in the state of the head of a passenger riding in a vehicle.

[0008] refer to Figure 1A and Figure 1B , the acceleration vector The trajectory of the vehicle changes intermittently at the time points when the vehicle's behavior changes, for example, rapid braking → sudden turning (1) and sudden turning → sudden acceleration (2), and the vehicle moves in a cross-shaped driving pattern. In this way, when the vehicle moves according to the cross-shaped driving pattern, the vehicle suddenly tilts to the left and right due to centrifugal force, and the user U riding in the vehicle has difficulty maintaining the desired body position due to inertia. Specifically, the human head of the user U who is not restrained by the safety device is shaken irregularly, and thus the discomfort of the passengers is increased. Summary of the invention

[0009] The present disclosure provides an apparatus for generating an acceleration curve and a method for automatic driving on a curve using the apparatus, so as to propose a driving mode defined by associating the movement of a vehicle in the longitudinal direction and the lateral direction when the vehicle travels on the curve, thereby alleviating the discomfort of passengers.

[0010] Other advantages, purposes and features of the present disclosure will be partially set forth in the following description, and will partially become apparent to those of ordinary skill in the art after reading the following, or may be learned from the practice of the present disclosure. The purposes and other advantages of the present disclosure may be achieved and obtained through the structures particularly pointed out in the written description and claims and the accompanying drawings.

[0011] To achieve these objectives and other advantages, and in accordance with the purposes of the present disclosure, as embodied and broadly described herein, a method for autonomous driving on a curve includes: detecting, by a processor, a curve in front of a vehicle and having a curvature equal to or greater than a threshold; calculating, by the processor, a target acceleration for entering the curve; generating, by the processor, a driving mode using the magnitude of the target acceleration; and calculating, by the processor, an acceleration curve based on the driving mode; outputting, by the processor, a control torque based on the acceleration curve, and controlling the vehicle.

[0012] The acceleration profile may include at least one of longitudinal acceleration, lateral acceleration, and steering angle.

[0013] The driving mode may correspond to a trajectory of an acceleration vector defined by associating a lateral acceleration of the vehicle when turning right or left with a longitudinal acceleration of the vehicle when accelerating or decelerating. The driving mode may include: a turning mode in which the magnitude of the acceleration vector remains constant and the direction of the acceleration vector changes along a circular trajectory; and an acceleration mode in which the magnitude and direction of the acceleration vector change along an elliptical trajectory.

[0014] Calculating the target acceleration may include comparing the vehicle's current speed to a speed limit for the curve.

[0015] Controlling the vehicle may include: during a first section corresponding to a section between a current position of the vehicle and a point at which the vehicle enters a curve, controlling deceleration based on a target acceleration; during a second section corresponding to a section between the first section and a point of maximum curvature of the curve, controlling the turning of the vehicle to reduce the magnitude of longitudinal acceleration based on the target acceleration; and during a third section corresponding to a section between the second section and a point at which the vehicle exits the curve, controlling the acceleration of the vehicle according to a maximum acceleration based on characteristics of the vehicle.

[0016] In this case, in a state where the sum of the longitudinal acceleration and the lateral acceleration is kept constant, controlled turning is performed to increase the magnitude of the lateral acceleration.

[0017] In another form of the present disclosure, an acceleration curve generating device may include: a road shape identifier configured to detect a curve in front of a vehicle with a curvature equal to or greater than a threshold; a driving mode generator configured to calculate a target acceleration for entering the curve and use the magnitude of the target acceleration to generate a driving mode; and a vehicle controller configured to calculate an acceleration curve based on the driving mode and output a control torque based on the acceleration curve.

[0018] Further areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the present disclosure easier to understand, various forms of the present disclosure will now be described by way of example with reference to the accompanying drawings, in which:

[0020] Figure 1A and Figure 1B is a diagram for explaining the discomfort felt by passengers when a vehicle is driven on a curved road using an advanced driver assistance system (ADAS) installed in a general autonomous vehicle;

[0021] Figure 2 is a schematic block diagram of an automatic driving control device;

[0022] Figure 3 A diagram for explaining a control method for driving a vehicle on a curved road;

[0023] Figure 4 is a diagram for explaining a method of generating a driving pattern defined by associating the motions in the longitudinal and lateral directions of a vehicle;

[0024] Figure 5A and Figure 5B is a diagram for explaining the discomfort of passengers based on the shape of the driving mode;

[0025] Figure 6is a diagram for explaining an acceleration curve when driving on a curve;

[0026] FIG. 7A to FIG. 7B is a diagram showing a comparative example of electromyogram (EMG) waves of the sternocleidomastoid muscle of a passenger riding in a rear seat of a vehicle according to the shape of a driving pattern; and

[0027] Figure 8 This is a flowchart for explaining a method of automatic driving on a curved road.

[0028] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. DETAILED DESCRIPTION

[0029] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate the same or corresponding parts and features.

[0030] It should be understood that the terms "vehicle" or "vehicular" or other similar terms used herein generally include motor vehicles, such as passenger cars including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, ships including various vessels, aircraft, etc., and include hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels produced from resources other than petroleum).

[0031] Although the exemplary form is described as using multiple units to perform the exemplary processing, it should be understood that the exemplary processing can also be performed by one or more modules. In addition, it should be understood that the term controller / control unit refers to hardware that includes a memory and a processor. The memory is configured as a storage module, and the processor is specifically configured as an execution module to perform one or more processes that will be further described below.

[0032] In addition, the control logic of the present disclosure may be embodied as a non-transitory computer-readable medium on a computer-readable medium containing executable program instructions executed by a processor, a controller / control unit, etc. Examples of computer-readable media include, but are not limited to, ROM, RAM, compact disk (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage device. The computer-readable recording medium may also be distributed in a computer system coupled to a network so that the computer-readable medium is stored and executed in a distributed manner, for example, by a telematics server or a controller area network (CAN).

[0033] Hereinafter, the forms will be described in detail with reference to the accompanying drawings. However, these forms may be embodied in many alternative forms, and the present disclosure should not be construed as limited to the forms set forth herein. Therefore, although the present disclosure is susceptible to various modifications and alternative forms, its specific forms are shown by way of example in the accompanying drawings and will be described in detail herein. However, it should be understood that it is not intended to limit the present disclosure to the specific forms disclosed, but on the contrary, the present disclosure will cover all modifications, equivalents and alternative forms that fall within the spirit and scope of the forms defined by the claims.

[0034] Herein, terms such as "first" and "second" are used only to describe various constituent elements, but these constituent elements are not limited by these terms. The terms are used only for the purpose of distinguishing one constituent element from another constituent element. In addition, the terms defined in consideration of the configuration and operation of the form are used only for illustrative purposes and are not intended to limit the scope of the form.

[0035] The terms used herein are only for the purpose of describing specific forms and are not intended to limit the inventive concept. As used herein, the singular forms "a", "an" and "the" are also intended to include plural forms, unless the context clearly indicates otherwise. It will also be understood that the terms "comprise" and / or "include" when used in this specification specify the presence of the features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0036] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concept belongs. It will also be understood that terms such as those defined in common dictionaries should be interpreted as having the same meaning as the contextual meaning in the relevant art, and should not be interpreted in an ideal or overly formal sense unless explicitly defined as such herein.

[0037] Hereinafter, each form of an automatic driving control device according to the present disclosure will be described with reference to the accompanying drawings.

[0038] Figure 2 is a schematic block diagram of an autonomous driving control device in a form according to the present disclosure.

[0039] Reference Figure 2 The automatic driving control device 10 may include a sensor information transmitter 100 , a map information transmitter 200 and an acceleration curve generating device 300 .

[0040] The sensor information transmitter 100 may include a camera 110 , a distance measurement sensor 120 , a global positioning system (GPS) receiver 130 , and a vehicle sensor 140 .

[0041] The camera 110 may acquire information about an image of an area surrounding the vehicle captured through an optical system, and may perform image processing such as noise removal, image quality and chromaticity adjustment, or file compression on the acquired image information.

[0042] The distance measuring sensor 120 may be implemented as a radar for measuring the distance to an object or a relative speed using electromagnetic waves and / or a lidar for using light to additionally observe blind spots that the radar cannot identify, and may measure the time it takes for electromagnetic waves or light emitted to an object to reach the object so as to measure the distance between the vehicle and the object.

[0043] The GPS receiver 130 may receive a navigation message from at least one GPS satellite located above the earth, and may collect location information of the vehicle.

[0044] The vehicle sensor 140 may include a speed sensor 141 , an acceleration sensor 143 , and a steering angle sensor 145 , which collect information about the vehicle's traveling speed, acceleration, steering angle, etc., and may periodically measure status information of various actuators.

[0045] The map information transmitter 200 may pre-store high-definition map information for distinguishing roads and lanes in the form of a database (DB), and may automatically update the map information at a predetermined time period via wireless communication, or may be manually updated by a user.

[0046] The map information may be configured in units of nodes and links, and may include information about the curvature (or curvature radius) of the road and position information of the curve corresponding to the curvature information. Here, a node may refer to a point where the characteristics of the road change, and a link may be classified into nodes and paths in units of lanes connecting the nodes.

[0047] The sensor information transmitter 100 and the map information transmitter 200 may communicate with the acceleration curve generating device 300 via a vehicle network (NW), and the vehicle network (NW) may include various in-vehicle communications, such as a controller area network (CAN), CAN with flexible data rate (CAN-FD), FlexRay, media oriented systems transport (MOST), or time-triggered Ethernet (TT Ethernet).

[0048] The acceleration curve generating device 300 may include a road shape recognizer 310, a driving mode generator 320, a vehicle controller 330, and a parameter storage device 340. Here, “recognizer”, “generator”, or “controller” should be understood as a unit that processes at least one function or operation and can be embodied in hardware (e.g., one or more processors), software, or a combination of hardware and software.

[0049] The road shape recognizer 310 may combine various information collected through the sensor information transmitter 100 and the map information transmitter 200 and may recognize the shape of a road in front of the vehicle.

[0050] The road shape identifier 310 can identify a curve in front of the vehicle with a curvature equal to or greater than a threshold based on road curvature information pre-stored in the map information transmitter 200, current vehicle position information received by the GPS receiver 130, surrounding image information analyzed by the camera 110, etc., and can send a command for generating a driving mode for the identified curve to the driving mode generator 320.

[0051] After receiving the command from the road shape recognizer 310, the driving pattern generator 320 may calculate the target acceleration G total To enter the curve, a circular shape with a target acceleration of |G can be generated. total | as the driving mode with the maximum radius r, which will be referred to below Figures 3 to 5B Detailed description.

[0052] Figure 3 1 is a diagram for explaining a control method for driving a vehicle traveling on a curved road according to one form of the present disclosure.

[0053] Reference Figure 3 The driving mode generator 320 can calculate the current speed V of the vehicle measured by the speed sensor 141. ego The speed limit V of the curve identified by the road shape identifier 310 limit Compare and calculate the target acceleration G total .

[0054] The driving pattern generator 320 may calculate the speed limit V based on information on the curvature (C) of the curve pre-stored in the map information transmitter 200 and the law of dynamics. limit , as the target acceleration G total Here, the speed limit V can be changed according to the friction coefficient and curvature of the road corresponding to the maximum speed entering the curve. limit .

[0055] The driving pattern generator 320 may take into account the curvature radius of the road (R=1 / C) and the centrifugal acceleration a limit To determine the speed limit V limit , and can be calculated, for example, using the following equation 1. Here, the centrifugal acceleration a limit The lateral acceleration may be a recommended lateral acceleration for preventing the vehicle from leaving the course when the vehicle turns on a curve, and may be preset within a range of 0.2 to 0.5 G, but the scope of the present invention is not limited thereto.

[0056] [Equation 1]

[0057]

[0058] The driving pattern generator 320 can use the above equation 1 to read the pre-written parameter storage device 340, which contains the curvature radius (R) and the speed limit V limit Alternatively, the speed limit V may be determined by using the legal speed limit for curves as specified in traffic regulations. limit .

[0059] When the current speed V ego Greater than the speed limit V limit When the driving mode generator 320 calculates the target acceleration G using the following equation 2 total , as the measured current speed V of the vehicle ego The speed limit V calculated for the curve limit The comparison results between .

[0060] [Equation 2]

[0061]

[0062] Here, V ego is the current speed of the vehicle, V limit is the speed limit of the curve, and S is the distance from the vehicle's current position O to the entry point A of the curve.

[0063] The driving mode generator 320 can be configured to generate a driving mode according to the current speed V ego Equal to or less than the speed limit V limit When the target acceleration G is calculated based on the vehicle speed total , as the measured current speed V of the vehicle ego The speed limit V calculated for the curve limit In this case, the target acceleration G can be determined by considering the rate of change of vehicle speed per hour. total .

[0064] When a vehicle is traveling on a curve, the behavior of the vehicle may change according to the flow of deceleration (①), turning (①→②→③), and acceleration (③→④→⑤), and therefore the acceleration vector of the vehicle In this case, even if the vehicle speed is within the speed limit V limit Slow down to enter the curve, when the acceleration vector When changing intermittently, depending on the characteristics of the road with a curvature equal to or greater than the threshold, the vehicle may also suddenly tilt left or right due to centrifugal force, and passengers in the vehicle may not maintain the desired body position due to inertia, thereby reducing ride comfort.

[0065] Therefore, the driving mode generator 320 may calculate the target acceleration G total To generate driving modes defined by linking the longitudinal and lateral motions of the vehicle.

[0066] Figure 4 is a view for explaining a method of generating a driving mode defined by associating longitudinal and lateral movements of a vehicle according to one form of the present disclosure.

[0067] Reference Figure 4 , the driving pattern generator 320 may draw a graph having a circular shape, such as a circle and / or an ellipse, with a target acceleration G measured from a center point O in the XY coordinates. total The XY coordinates are two-dimensional (2D) space, and considering the turning direction of the vehicle, a driving pattern DP following the graph can be generated. For example, the graphs shown in the first and fourth quadrants in the XY coordinates indicate a vehicle driving pattern when turning right, while the graphs shown in the second and third quadrants indicate a vehicle driving pattern when turning left.

[0068] This graph is an element for representing the overall longitudinal and lateral movement of a vehicle traveling on a curve, and can be defined as a boundary line for classifying the behavior of the vehicle into a safe area and a dangerous area. For example, when the vehicle moves outside the boundary line range of the graph (M1), the behavior of the vehicle falls within the dangerous area, and there is a high probability that the vehicle will leave the curve, and when the vehicle is positioned within the boundary line range of the graph (M2), the behavior of the vehicle falls within the safe area.

[0069] Here, the X-axis of the graph is the lateral acceleration a when turning left or right. y , the Y axis of the graph is the longitudinal acceleration a during acceleration and deceleration x , the vehicle's acceleration a can be calculated from the longitudinal acceleration a x and lateral acceleration a y The vector sum express.

[0070] The driving pattern generator 320 can represent the longitudinal acceleration a in the form of a graph by x and lateral acceleration a y The acceleration vector defined in relation to The trajectory of the vehicle is used to quantitatively analyze the riding comfort of the passengers in the vehicle, and the shape and area of ​​the graph can be determined according to the target acceleration G totalMake various adjustments to the size.

[0071] Points A, B, and C on the graph may indicate states where the control state of the vehicle changes, point A may be the point where the vehicle enters a curve, point B may be the point corresponding to the maximum curvature of the curve, point C may be the point where the vehicle leaves the curve, and the center point O may correspond to the current position of the vehicle.

[0072] The driving mode generator 320 can generate a driving mode DP, which includes a deceleration mode corresponding to OA of the curve (hereinafter referred to as "deceleration section"), a turning mode corresponding to AB (hereinafter referred to as "turning section") and an acceleration mode corresponding to BC (hereinafter referred to as "acceleration section"), and can send the driving mode DP to the vehicle controller 330.

[0073] When receiving a command for generating a driving mode through the road shape recognizer 310, the driving mode generator 320 may generate a deceleration mode in which the longitudinal acceleration a x The magnitude of the deceleration section follows the target acceleration G with respect to the center point O and the point A with the maximum negative acceleration on the longitudinal direction Y axis. total In this case, the driving mode generator 320 can calculate the longitudinal acceleration a x Reach target acceleration G total The point is determined as point A.

[0074] The driving pattern generator 320 may generate a turning pattern with respect to a turning section between a point A having a maximum negative acceleration on the Y axis in the longitudinal direction and a point B having a maximum positive (or negative) acceleration on the X axis in the lateral direction using the relational expression of the following equation 3. Here, point B in the XY coordinates may have a maximum positive acceleration or a negative acceleration depending on the direction in which the vehicle turns.

[0075] [Equation 3]

[0076] a x 2 +a y 2 =G total 2

[0077] When the acceleration vector The acceleration vector of the steering mode is It can move along a diagram having a circular shape, and can gradually reduce the longitudinal deceleration a x scalar, and the lateral acceleration a y The scalar value of may gradually increase over time. In this case, the driving mode generator 320 may calculate the longitudinal acceleration a within the boundary line range of the figure.x has a minimum value (or 0) and the lateral acceleration a y The point with the maximum value (or the largest radius r) is determined as point B.

[0078] The driving pattern generator 320 may generate an acceleration pattern with respect to an acceleration section between a point B having a maximum positive (or negative) acceleration on the X-axis in the lateral direction and a point C having a maximum positive acceleration on the Y-axis in the longitudinal direction using the relational expression of Equation 4 below.

[0079] [Equation 4]

[0080]

[0081] When the acceleration vector When both the scalar and direction of the acceleration mode change, the acceleration vector can be moved along the elliptical graph, in which case G max It is the maximum acceleration based on the vehicle characteristics. Unlike the turning section where the vehicle enters the curve, in the acceleration section where the vehicle leaves the curve, the vehicle cannot accelerate with a vehicle power greater than the vehicle's maximum output range, and when the vehicle suddenly accelerates at a low speed, wheel slip due to tire slip may occur.

[0082] Therefore, the magnitude of the target acceleration |G max | and the safety factor α(G max =α|G max |, where α satisfies the range of 0<α<1) to determine the maximum acceleration G of the acceleration section max , and the safety factor α may be a value preset by a developer in consideration of the performance limit of an engine installed in a vehicle.

[0083] The driving pattern generator 320 may generate a longitudinal acceleration a over time. x The scalar gradually increases while the lateral acceleration a y The scalar acceleration mode gradually decreases, and the lateral acceleration a can be within the range of the boundary line of the figure y has a minimum value (or 0), while the longitudinal acceleration a x Reaching maximum acceleration G max The point is determined as point C.

[0084] Figure 5A and Figure 5B is a view for explaining discomfort of a passenger based on a shape of a driving mode according to one form of the present disclosure.

[0085] Figure 5Ais a diagram showing a driving pattern of a vehicle that is exhibited according to a sequence of deceleration, turning, and acceleration when the vehicle travels on a curve. Figure 5B This is a diagram that qualitatively shows the change in the state of the head of a passenger riding in a vehicle.

[0086] refer to Figure 5A and Figure 5B , the acceleration vector The trajectory of changes continuously at the time points when the behavior of the vehicle changes, for example, deceleration → turning (1'), turning → acceleration (2'), and the vehicle moves according to the driving pattern in a circular shape.

[0087] In this way, when the vehicle moves in the circular driving pattern, the centrifugal force applied to the vehicle and the inertial force applied to the user U have approximately the same magnitude and direction, and thus, the orientation of the head of the user U can be changed in a regular direction. For example, the head of the user U can move in a circular shape in the same direction as the direction in which the body of the user U moves, and thus the discomfort of the passengers can be reduced and the riding comfort can be improved.

[0088] Return to reference Figure 2 The vehicle controller 330 may include a longitudinal direction controller 331 , a lateral direction controller 333 , and a turning state determiner 335 .

[0089] The vehicle controller 330 may receive the driving pattern DP including deceleration, turning, and acceleration patterns from the driving pattern generator 320, may convert the driving pattern DP into a time acceleration curve, and may calculate at least one of the following: longitudinal acceleration a x , lateral acceleration a y and steering angle δ in order to quantitatively analyze the behavior of the vehicle, which will be referenced below including Figure 6 The accompanying drawings are described in detail.

[0090] Figure 6 is a graph for explaining an acceleration curve for traveling on a curve according to one form of the present disclosure.

[0091] The vehicle controller 330 can calculate an acceleration curve for each of the longitudinal and lateral directions, can output a control torque based on the acceleration curve as at least one of an engine device (not shown), a braking device (not shown) and a steering device (not shown), and can control deceleration, turning and acceleration of the vehicle.

[0092] In this case, Figure 6 In the graph shown, the X-axis represents time, and the Y-axis represents acceleration, which can be expressed in units of gravitational force (G force). Based on the X-axis, the upper side refers to the behavior of the vehicle in the acceleration state, and the lower side refers to the behavior of the vehicle in the deceleration state.

[0093] The longitudinal direction controller 331 and the lateral direction controller 333 may convert the driving mode DP corresponding to each deceleration, turning, and acceleration mode into an acceleration curve, and may calculate the longitudinal acceleration a x , lateral acceleration a y and steering angle δ, and the vehicle controller 330 may control the vehicle for each of the deceleration, turning, and acceleration sections as described below.

[0094] Speed ​​reduction section

[0095] The vehicle controller 330 may consider the target acceleration G during the deceleration section corresponding to the section between the current position O and the entry point A of the curve. total To calculate the longitudinal acceleration a x , which can be combined with the longitudinal acceleration a x The corresponding braking torque (eg, a signal value of a brake pedal sensor (BPS)) is output to a braking device (not shown), and the deceleration of the vehicle can be controlled (see Figure 3 ①).

[0096] The longitudinal direction controller 331 may generate the longitudinal acceleration a based on a linear function (or a nonlinear function) having a negative (-) slope. x The magnitude of the acceleration G gradually increases to follow the target acceleration G total acceleration curve, and when the rate of change of longitudinal acceleration (J = d ax / d t , where d ax When dt is the change in longitudinal acceleration and dt is the change in time) reaches 0, the vehicle controller 330 may perform control to change the state of the vehicle from the deceleration state to the turning state.

[0097] Turning section

[0098] The vehicle controller 330 may consider the magnitude of the target acceleration |G during a turning section corresponding to a section between the deceleration section and the maximum curvature point B of the curve. total |, to calculate the acceleration vector Continuously changing longitudinal acceleration a x and lateral acceleration a y , which can be combined with the longitudinal acceleration a x and lateral acceleration a y The corresponding braking torque and steering torque are output to a braking device (not shown) and a steering device (not shown), and the turning of the vehicle can be controlled (see Figure 3 ①, ② and ③).

[0099] The longitudinal direction controller 331 may generate the longitudinal acceleration a based on a linear function (or a nonlinear function) having a positive (+) slope. x The acceleration curve gradually decreases in size until it reaches a minimum value (or 0), and the acceleration curve can be sent to the lateral direction controller 333.

[0100] Considering the longitudinal acceleration a received from the longitudinal direction controller 331 x , the lateral direction controller 333 may calculate the lateral acceleration a using the following equation 5: y and steering angle δ. The lateral direction controller 333 may generate an acceleration curve, wherein the longitudinal acceleration a x and lateral acceleration a y When the sum of the two remains constant, the lateral acceleration a y The size increases over time.

[0101] [Equation 5]

[0102] (1)

[0103] (2)

[0104] Here, R is the radius of curvature, L is the wheelbase of the vehicle, K is the slope of understeer, and the longitudinal acceleration a is calculated in the curve. x and lateral acceleration a y The sum of the two remains constant. In this case, the constant value can be equal to the magnitude of the target acceleration |G total |Or the maximum radius r of driving mode DP.

[0105] When the longitudinal acceleration a x has a minimum value (or 0) and the lateral acceleration a y When the maximum value (or maximum radius r) is reached, the vehicle controller 330 may change the control of the vehicle from the turning state to the acceleration state.

[0106] Acceleration section

[0107] The vehicle controller 330 may consider the maximum acceleration G based on the characteristics of the vehicle during the acceleration section corresponding to the section between the turning section and the starting point C of the curve. max To calculate the longitudinal acceleration a x and lateral acceleration a y , which can be combined with the longitudinal acceleration a x and lateral acceleration a y The corresponding driving torque (for example, the signal value of the accelerator pedal sensor (APS)) and the steering torque are output to the engine device (not shown) and the steering device (not shown), and the acceleration of the vehicle can be controlled (see Figure 3 ③, ④ and ⑤).

[0108] The lateral direction controller 333 can generate an acceleration curve, wherein the lateral acceleration a y The displacement of the steering angle δ is gradually reduced in consideration of the restoring force, whereby the displacement of the steering angle δ returns to the neutral position of the steering wheel, and the acceleration curve may be sent to the longitudinal direction controller 331 .

[0109] The longitudinal direction controller 331 may consider the lateral acceleration a received from the lateral direction controller 333. y , calculate the longitudinal acceleration a using equation 6 below x , and an acceleration curve can be generated, where the longitudinal acceleration a x The magnitude increases to thus follow the maximum acceleration G with time max .

[0110] [Equation 6]

[0111] (where a x ≤G max )

[0112] Here, G max It can be a maximum acceleration based on the characteristics of the vehicle and can be based on the magnitude of the target acceleration |G max | and is determined by a safety factor α based on the characteristics of the vehicle, and the safety factor α may be a value preset by a developer in consideration of the performance limit of an engine installed in the vehicle.

[0113] When the steering angle δ of the vehicle measured by the steering angle sensor 145 reaches 0, the vehicle controller 330 may regard that the vehicle has left the curve and may terminate the control.

[0114] The turning state determiner 335 may periodically compare the estimated lateral acceleration calculated by the lateral direction controller 333 with the measured lateral acceleration detected by the acceleration sensor 143 and may determine the turning state of the vehicle.

[0115] The turning state determiner 335 may compare the difference between the estimated lateral acceleration and the measured lateral acceleration with a preset reference value, and may determine whether the turning state of the vehicle traveling on the curve is a normal state or an abnormal state based on the comparison result.

[0116] When the difference between the estimated lateral acceleration and the measured lateral acceleration is less than a reference value, the turning state determiner 335 may determine that the curve is in a normal state, and when the difference is greater than a reference value, the turning state determiner 335 may determine that the turning state on the curve is abnormal (e.g., an oversteering state in which the vehicle tilts to the inside of the turning direction; or an understeering state in which the vehicle deviates from the turning direction). When it is determined that the state of turning on the curve is abnormal, the turning state determiner 335 may send a fault flag to a vehicle dynamics control (VDC) (not shown), and the VDC (not shown) may apply a compensation torque to a brake device (not shown).

[0117] The parameter storage device 340 may store the target acceleration G calculated and generated by the driving mode generator 320. total and driving mode DP, and acceleration curves with respect to the longitudinal and lateral directions, corresponding to the driving mode DP calculated by the vehicle controller 330. The parameter storage device 340 may pre-store the speed limit V corresponding to the curvature radius R in the form of a table. limit The parameter storage device 340 may be embodied as one or more memory types, such as a flash memory, a hard disk, a secure digital (SD) card, a random access memory (RAM), a read-only memory (ROM), or a network storage device.

[0118] The following will refer to Fig. 7A and Figure 7B Effects obtained when a vehicle is controlled based on a driving mode according to one form of the present disclosure are described.

[0119] FIG. 7A to FIG. 7B is a view showing a comparative example of electromyogram (EMG) waves of the sternocleidomastoid muscle of a passenger riding in a rear seat of a vehicle according to the shape of a driving pattern. Fig. 7A Shown according to Figure 1A Electromyography (EMG) waveform of the sternocleidomastoid muscle in the cruciate driving pattern is shown. Figure 7B It shows that according to FIG. 5A to FIG. 5B The circular shape of the driving pattern of the sternocleidomastoid muscle is shown in the electromyography (EMG) wave.

[0120] The sternocleidomastoid muscle is a muscle for maintaining the head posture in response to the inertial force applied to the human body, and the electromyography (EMG) wave of the sternocleidomastoid muscle may be analyzed to qualitatively estimate the discomfort of the passenger. Here, electromyography (EMG) refers to the use of electrical signals generated from the muscle surface along the muscle fibers according to the movement of the sternocleidomastoid muscle when the muscle contracts and releases.

[0121] Fig. 7A and Figure 7BThe raw EMG waves shown in can be used to analyze the activation frequency and response cycle of the muscle, and the integrated EMG waves can be used to analyze the fatigue and burden of the muscle.

[0122] As from Fig. 7A As can be seen in Figure 2, when the vehicle moves according to the cross-shaped driving pattern, the amplitude of the original EMG wave increases sharply when the vehicle enters a curve, and thereafter, muscle activity may respond to the application of lateral acceleration and longitudinal acceleration until the vehicle leaves the curved road. That is, the current state represents a state in which the muscle has a short activation frequency and a short response cycle and repeatedly contracts and releases in a short time. It can be seen that according to the integrated EMG wave, at the time point when the vehicle enters the curve, the maximum voluntary contraction (MVC) may be greater than about 20%, and the muscle burden of the passenger increases due to rapid braking, sudden steering, and sudden acceleration.

[0123] In contrast, reference Figure 7B , when the vehicle moves along the circular driving pattern, the amplitude of the original EMG wave can gradually increase from the time point when the vehicle enters the curve, and then, stable muscle activity can be maintained with an approximately constant amplitude until the vehicle leaves the curve. It can be seen that according to the integrated EMG wave, at the time point when the vehicle enters the curve, Fig. 7A In comparison, the maximum voluntary contraction (MVC) can be reduced by about 7%. That is, according to one form of the present disclosure, when the vehicle travels on a curve according to a circular driving pattern, the burden on the sternocleidomastoid muscle can be reduced, and therefore, the discomfort of the passengers riding in the vehicle can be reduced.

[0124] Figure 8 is a flowchart for illustrating a method for automated driving on a curved road according to one form of the present disclosure.

[0125] Reference Figure 8 , the method S800 for autonomous driving on a curve may include a curve detection operation S810 , a target acceleration calculation operation S820 , a driving pattern generation operation S830 , and a vehicle control operation S840 .

[0126] First, the road shape recognizer 310 may combine various information collected through the sensor information transmitter 100 and the map information transmitter 200, and may detect a curve, which is in front of the vehicle and has a curvature equal to or greater than a threshold value (S810).

[0127] Then, the driving pattern generator 320 may calculate the target acceleration G total To enter the detected curve (S820).

[0128] The driving pattern generator 320 may generate a circular driving pattern DP, wherein the magnitude of the target acceleration G totalis the maximum radius r in the XY coordinates (S830).

[0129] Then, the vehicle controller 330 may convert the driving pattern DP into a time acceleration curve, and may calculate the longitudinal acceleration a x , lateral acceleration a y and steering angle δ to quantitatively analyze the behavior of the vehicle, a control torque based on the acceleration curve may be output to at least one of an engine device (not shown), a brake device (not shown), and a steering device (not shown), and deceleration, turning, and acceleration of the vehicle may be controlled (S840). Operation S840 will be described in more detail.

[0130] The vehicle controller 330 may calculate the following target acceleration G during the deceleration section corresponding to the section between the current position O and the entry point A of the curve. total The longitudinal acceleration a x , which can be combined with the longitudinal acceleration a x The corresponding braking torque is output to a braking device (not shown), and deceleration of the vehicle may be controlled ( S841 ).

[0131] The vehicle controller 330 may then determine the rate of change of the longitudinal acceleration (J=da x / d t , where da x is the change in longitudinal acceleration and d t is the change in time) can reach 0 and the control state of the vehicle can be changed (S842).

[0132] When the rate of change J of the longitudinal acceleration is equal to or greater than 0, the control state may be changed from deceleration to turning (S842 is "yes"), and the vehicle controller 330 may consider the magnitude of the target acceleration |G during the turning section corresponding to the section between the deceleration section and the maximum curvature point B of the curve. total |To calculate the acceleration vector Continuously changing longitudinal acceleration a x and lateral acceleration a y , which can be combined with the longitudinal acceleration a x and lateral acceleration a y The corresponding braking torque and steering torque are output to a braking device (not shown) and a steering device (not shown), and the turning of the vehicle can be controlled (S843). In this case, the longitudinal acceleration a x The magnitude of the lateral acceleration a can be gradually reduced. y The magnitude of the longitudinal acceleration a can be gradually increased, and the longitudinal acceleration a x and lateral acceleration a y The sum of the target acceleration can be kept constant (for example, the magnitude of the target acceleration |G total| or the maximum radius r of driving mode DP).

[0133] On the contrary, when the change rate J of the longitudinal acceleration is less than 0, the deceleration control may be continuously performed (“NO” of operation S842 ).

[0134] The vehicle controller 330 may then determine the longitudinal acceleration a x Whether it has a minimum value (or 0) and the lateral acceleration a y Whether it has a maximum value (or a maximum radius r), and the control state of the vehicle can be changed (S844).

[0135] When the longitudinal acceleration a x has a minimum value and the lateral acceleration a y When the maximum value is reached, the control state may be changed from turning to acceleration (operation S844 is "yes"), and the vehicle controller 330 may consider the maximum acceleration G based on the characteristics of the vehicle during the acceleration section corresponding to the section between the turning section and the starting point C of the curve. max , to calculate the longitudinal acceleration a x and lateral acceleration a y , which can be combined with the longitudinal acceleration a x and lateral acceleration a y The corresponding driving torque and steering torque are output to the engine device (not shown) and the steering device (not shown), and the acceleration of the vehicle can be controlled (S845). In this case, the lateral acceleration a can be controlled by considering the restoring force of the displacement of the steering angle δ to return to the neutral position of the steering wheel. y Set to gradually decrease.

[0136] On the contrary, when the longitudinal acceleration a x Does not meet the minimum value or lateral acceleration a y When the maximum value is not reached, the turning control may be continuously performed (operation S844: No).

[0137] Then, the vehicle controller 330 may determine whether the steering angle δ of the vehicle measured by the steering angle sensor 145 reaches 0 (S846). When the above conditions are met, it can be considered that the vehicle has left the curve, and the control can be terminated (operation S846 is "yes"), otherwise, the acceleration control can be continuously performed (operation S846 is "no").

[0138] According to another aspect of the present disclosure, the road shape recognizer 310, the driving mode generator 320, and the vehicle controller 330 may refer to a hardware device including one or more processors to execute instructions to perform all or part of the steps in the above method. The instructions executed by the one or more processors may include: detecting a curve in front of the vehicle and having a curvature equal to or greater than a threshold; calculating a target acceleration for entering the curve; generating a driving mode using the magnitude of the target acceleration; calculating an acceleration curve based on the driving mode, outputting a control torque according to the acceleration curve, and controlling the vehicle.

[0139] According to at least one form of the present disclosure, a driving mode defined by associating motion in the longitudinal and lateral directions can be proposed to quantitatively analyze the discomfort of a passenger, and the deceleration, turning, and acceleration of the vehicle can be controlled based on the analysis result, and thus user-friendly autonomous driving can be achieved in consideration of the road environment. Therefore, the unfamiliarity between the vehicle driving behavior and the passenger's expectations can be reduced, and the discomfort of the passenger can be effectively reduced.

[0140] Those skilled in the art will appreciate that the effects achievable with the present disclosure are not limited to what has been specifically described above, and other advantages of the present disclosure will be more clearly understood from the detailed description.

[0141] The method for automatic driving on a curved road according to the above exemplary form can be programmed to be executed in a computer and can be stored on a non-transitory computer-readable recording medium. Examples of non-transitory computer-readable recording media include read-only memory (ROM), random access memory (RAM), CD-ROM, magnetic tape, floppy disk, optical data storage device, etc.

[0142] The non-transitory computer readable recording medium can also be distributed on a network coupled computer system so that the computer readable code is stored and executed in a distributed manner. Moreover, programmers in the art to which the present disclosure pertains can easily construct functional programs, codes, and code segments for completing the present disclosure.

[0143] Although only a few forms are described above, various other forms are also possible. Unless they are incompatible technologies, the technical ideas of the above forms can be combined into various forms, thereby realizing new forms.

[0144] Those skilled in the art will recognize that the present disclosure may be performed in other specific ways than those set forth herein without departing from the spirit and essential features of the present disclosure. Therefore, the above forms should be interpreted in all respects as illustrative and not restrictive. The scope of the present disclosure should be determined by the appended claims and their legal equivalents, rather than by the above description, and all changes falling within the meaning and equivalent range of the appended claims should be included therein.

Claims

1. A method for automatic driving on a curved road, the method comprising: detecting, by a processor, a curve in front of the vehicle and having a curvature equal to or greater than a threshold; The processor calculates a target acceleration for entering the curve; The processor generates a driving mode using the magnitude of the target acceleration; and calculating, by the processor, an acceleration profile based on the driving mode; and The processor outputs a control torque based on the acceleration curve and controls the vehicle, The driving mode is defined by associating the longitudinal and lateral movements of the vehicle when traveling on the curve. wherein the driving mode corresponds to a trajectory of an acceleration vector defined by associating a lateral acceleration of the vehicle when turning right or left with a longitudinal acceleration of the vehicle when accelerating or decelerating, The driving modes include: A turning mode in which the magnitude of the acceleration vector remains constant and the direction of the acceleration vector changes along a circular trajectory; and The acceleration mode in which the magnitude and direction of the acceleration vector change along an elliptical trajectory, Controlling the vehicle comprises: controlling deceleration based on the target acceleration during a first section corresponding to a section between a current position of the vehicle and a point at which the vehicle enters the curve; During a second section corresponding to a section between the first section and a point of maximum curvature of the curve, based on the target acceleration, controlling the turning of the vehicle to reduce the magnitude of the longitudinal acceleration; During a third section corresponding to a section between the second section and a point at which the vehicle exits the curve, acceleration of the vehicle is controlled according to a maximum acceleration based on characteristics of the vehicle.

2. The method according to claim 1, wherein: The acceleration curve includes at least one of longitudinal acceleration, lateral acceleration and steering angle.

3. The method according to claim 1, wherein: Calculating the target acceleration includes comparing a current speed of the vehicle with a speed limit of the curve.

4. The method according to claim 1, wherein: In a state where the sum of the longitudinal acceleration and the lateral acceleration is kept constant, controlled turning is performed to increase the magnitude of the lateral acceleration. 5 . A computer-readable recording medium configured to store an application program executed by a processor to perform the method according to claim 1 .

6. An acceleration curve generating device, comprising: a road shape recognizer configured to detect a curve ahead of the vehicle with a curvature equal to or greater than a threshold; a driving pattern generator configured to calculate a target acceleration for entering the curve and generate a driving pattern using a magnitude of the target acceleration; and a vehicle controller configured to calculate an acceleration profile based on the driving mode and output a control torque based on the acceleration profile, The driving mode is defined by associating the longitudinal and lateral movements of the vehicle when traveling on the curve. wherein the driving mode corresponds to a trajectory of an acceleration vector defined by associating a lateral acceleration of the vehicle when turning right or left with a longitudinal acceleration of the vehicle when accelerating or decelerating, The driving modes include: A turning mode in which the magnitude of the acceleration vector remains constant and the direction of the acceleration vector changes along a circular trajectory; and The acceleration mode in which the magnitude and direction of the acceleration vector change along an elliptical trajectory, in, the vehicle controller being configured to control deceleration of the vehicle based on the target acceleration during a first section corresponding to a section between a current position of the vehicle and a point at which the vehicle enters the curve, The vehicle controller is configured to control the turning of the vehicle to reduce the magnitude of the longitudinal acceleration based on the target acceleration during a second section corresponding to a section between the first section and a point of maximum curvature of the curve, The vehicle controller is configured to control acceleration of the vehicle according to a maximum acceleration based on characteristics of the vehicle during a third section corresponding to a section between the second section and a point at which the vehicle exits the curve.

7. The acceleration curve generating device according to claim 6, wherein: The acceleration curve includes at least one of longitudinal acceleration, lateral acceleration and steering angle.

8. The acceleration curve generating device according to claim 6, wherein: The target acceleration is determined by comparing a current speed of the vehicle with a speed limit of the curve.

9. The acceleration curve generating device according to claim 6, wherein: The vehicle controller is configured to control the turning of the vehicle to increase the magnitude of the lateral acceleration in a state in which the sum of the longitudinal acceleration and the lateral acceleration is kept constant.

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