Regenerative braking control method for vehicle

Abstract

The invention relates to a regenerative braking control method of a vehicle. A regenerative braking control method of a vehicle includes determining whether a specified downhill cruise condition is satisfied in response to an accelerator pedal release in an on state of a regenerative braking switch; when it is determined that the downhill cruise condition is satisfied, if a specified preliminary obstacle does not exist in front of the vehicle, a target deceleration of the vehicle is set as a specified deceleration for downhill cruise; determining the torque required by the vehicle to decelerate at the target deceleration; regenerative braking is preferentially utilized to generate the torque required in the vehicle.

Description

Technical Field

[0001] The present invention relates to a technique for controlling regenerative braking torque of a vehicle. Background Art

[0002] Conventional environmentally friendly commercial vehicles may be provided with lever-type or paddle-type regenerative braking devices, and quite a number of drivers utilize the regenerative braking devices in a stable state without further manipulation, rather than actively manipulating the regenerative braking devices appropriately according to the driving state of the vehicle.

[0003] The reason is that it is troublesome for the driver to operate the regenerative braking device according to the driving state of the vehicle and to appropriately adjust the regenerative braking amount of the vehicle according to the driving state of the vehicle, and if the regenerative braking device is not properly controlled and the regenerative braking amount of the vehicle is not properly controlled, the energy efficiency of the vehicle will be relatively reduced.

[0004] The information included in this background of the invention is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgment or any form of suggestion that this information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] Various aspects of the present invention are directed to providing a regenerative braking control method for a vehicle, which can automatically control the amount of regenerative braking suitable for the vehicle's driving conditions, thereby greatly improving the vehicle's energy efficiency while improving driving convenience by minimizing the driver's manipulation of regenerative braking.

[0006] According to one aspect of the present invention, the above and other objects can be achieved by providing a regenerative braking control method for a vehicle, the method comprising: in the on state of a regenerative braking switch, in response to the release of an accelerator pedal, determining whether a specified downhill cruising condition is satisfied; when it is determined that the downhill cruising condition is satisfied, in response to the absence of a specified preparatory obstacle in front of the vehicle, setting the target deceleration of the vehicle to a specified deceleration for downhill cruising; determining the torque required for the vehicle to decelerate at the target deceleration; and preferentially utilizing regenerative braking to generate the torque required in the vehicle.

[0007] In the on state of the regenerative brake switch, in response to the current vehicle speed being greater than or equal to the target vehicle speed, it can be determined that the downhill cruising condition is met, where the target vehicle speed is determined by adding a specified pre-input vehicle speed value to the vehicle speed in response to the accelerator pedal being released.

[0008] When it is determined that the downhill cruising condition is not satisfied, the target deceleration may be set to a minimum value among candidate decelerations determined according to the slope of the road on which the vehicle is traveling and the prepared obstacle.

[0009] In response to the road on which the vehicle is traveling being a flat road or an uphill road, one of the candidate decelerations may be determined as a deceleration for coasting, and the deceleration for coasting may be a predetermined constant value.

[0010] In response to the road on which the vehicle is traveling being a downhill road, one of the candidate decelerations may be determined as the deceleration for downhill cruising, and the deceleration for downhill cruising may be set according to a difference between the target vehicle speed and the current vehicle speed.

[0011] In response to the preparatory obstacle being a speed camera, one of the candidate decelerations may be determined as the deceleration for the stationary obstacle, and the deceleration for the stationary obstacle may be set to a deceleration required for the vehicle to reach the speed limit of the speed camera in response to the vehicle reaching the execution position of the speed camera.

[0012] The deceleration rate for a stationary obstacle can be determined by the following equation:

[0013]

[0014] a cam : deceleration for stationary obstacles,

[0015] v cam : Speed ​​limit of speed camera,

[0016] v cur : Current vehicle speed,

[0017] d cam : The distance from the vehicle’s current position to the speed camera,

[0018] d min : Minimum distance to prevent division by zero.

[0019] In response to the prepared obstacle being a leading vehicle, one of the candidate decelerations may be determined as a deceleration for moving the obstacle, and the deceleration for moving the obstacle may be set to a deceleration required for the vehicle to maintain an appropriate inter-vehicle distance with the leading vehicle.

[0020] The deceleration for moving the obstacle may be one selected from a deceleration for moving the obstacle based on a first mode configured to facilitate maintaining an appropriate inter-vehicle distance with the preceding vehicle during braking of the preceding vehicle and a deceleration for moving the obstacle based on a second mode configured to facilitate maintaining an appropriate inter-vehicle distance with the preceding vehicle during cruising of the preceding vehicle.

[0021] The deceleration rate used to move the obstacle can be determined by the following equation:

[0022] aref =β×a ctg +(1-β)×a ca ,

[0023]

[0024] In the first mode,

[0025] In the second mode,

[0026] a ref : deceleration used for moving obstacles,

[0027] β: Mixing ratio (adjustment value based on relative speed and relative distance),

[0028] h: time gap constant in constant time gap control,

[0029] λ: sliding gradient (as the sliding gradient increases, the distance control becomes faster),

[0030] v ego : The speed of the vehicle,

[0031] d min : The minimum distance to be maintained,

[0032] d rel : the distance to the vehicle ahead,

[0033] v rel : relative speed,

[0034] v front : The speed of the vehicle ahead,

[0035] D: Appropriate distance between vehicles.

[0036] The appropriate inter-vehicle distance D can be determined from a map that represents the inter-vehicle distance based on the current vehicle speed and the relative speed of the vehicles.

[0037] When it is determined that the downhill cruising condition is satisfied, in response to the presence of a preparatory obstacle ahead, the target deceleration may be set to a minimum value among the candidate decelerations.

[0038] The required torque may be determined by adding the slope compensation torque, the air resistance compensation torque, and the rolling resistance compensation torque to a reference torque obtained by multiplying the target deceleration by the vehicle weight and the dynamic load radius of the tire.

[0039] The required torque can be determined by adding the slope compensation torque and the feedback compensation torque to a reference torque obtained by multiplying the target deceleration by the vehicle weight and the dynamic load radius of the tire.

[0040] The feedback compensation torque can be determined by the following equation:

[0041]

[0042] T fb : Feedback compensation torque,

[0043] T mot : Motor torque,

[0044] T rtd : Reducer torque,

[0045] r: dynamic load radius of the tire,

[0046] Estimated vehicle weight,

[0047] a veh : The current acceleration of the vehicle.

[0048] In generating the required torque in the vehicle, the regenerative braking torque may be gradually replaced by the retarder torque in response to the vehicle speed decreasing to or below the designated transition speed.

[0049] According to another aspect of the present invention, a regenerative braking control system for a vehicle is provided, the system comprising a controller, a regenerative braking switch, an accelerator pedal sensor, a motor and a retarder, the controller being configured to execute the above-mentioned regenerative braking control method, the regenerative braking switch being configured to provide a signal to the controller indicating a user's selection to activate the regenerative braking function of the vehicle, the accelerator pedal sensor being configured to detect the release of the accelerator pedal and to provide information related to the accelerator pedal to the controller, the motor and the retarder being controlled by the controller and being configured to generate the torque required in the vehicle.

[0050] The regenerative braking control system may further include a navigation system and at least one of a forward camera or a forward radio detection and ranging (RADAR), wherein the navigation system is configured to provide information related to a speed camera in front of the vehicle's path, and at least one of the forward camera or the RADAR is configured to detect information related to a leading vehicle in front of the vehicle's path.

[0051] The regenerative braking control system may further include a mode selection switch configured to select determination of the target deceleration to a different value in response to the presence of a leading vehicle ahead.

[0052] The methods and apparatus of the present invention have other features and advantages that will be apparent from, or will be described in detail in, the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a block diagram of a regenerative braking control system for a vehicle according to an exemplary embodiment of the present invention;

[0054] Figure 2 and Figure 3 is a flowchart showing a regenerative braking control method of a vehicle according to an exemplary embodiment of the present invention; and

[0055] Figure 4 This is a map showing the distance between vehicles based on vehicle speeds and relative speeds.

[0056] It should be understood that the drawings are not necessarily drawn to scale, but rather are schematically simplified to present various features to show the basic principles of the present invention. The predetermined design features of the present invention included herein (including, for example, specific size, orientation, position and shape) will be determined in part by the specific environment to be applied and used.

[0057] In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. DETAILED DESCRIPTION

[0058] The following will be referred to in detail various embodiments of the present invention, examples of which are shown in the accompanying drawings and are described below. Although the present invention will be described in conjunction with the exemplary embodiments of the present invention, it should be understood that this specification is not intended to limit the present invention to those exemplary embodiments. On the other hand, the present invention is intended to not only cover the exemplary embodiments of the present invention, but also cover various alternatives, modifications, equivalents and other embodiments that may be included in the spirit and scope of the present invention as defined by the appended claims.

[0059] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to designate the same or similar parts, and redundant description will be omitted.

[0060] In the following description of the embodiments, suffixes such as "module", "component" and "unit" are provided or used interchangeably only in consideration of the convenience of description and do not have mutually distinguished meanings or functions.

[0061] In the following description of the exemplary embodiments of the present invention, when the specific description of the known functions and configurations in combination with this document would make the subject matter of the present invention quite unclear, these specific descriptions will be omitted. In addition, the accompanying drawings will be provided exemplarily to describe the exemplary embodiments of the present invention, and should not be interpreted as being limited to the exemplary embodiments set forth herein, and it should be understood that only exemplary embodiments of the present invention are provided to fully include the present invention and cover modifications, equivalents or alternatives within the scope and technical scope of the present invention.

[0062] In the following description of the embodiments, terms such as "first" and "second" are used only to describe various elements, and these elements should not be construed as being limited by these terms. These terms are used only to distinguish one element from another element.

[0063] When an element or layer is referred to as being “connected to” or “coupled to” another element or layer, it may be directly connected to or coupled to the other element or layer, or intervening elements or layers may be present. Conversely, when an element or layer is referred to as being “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers.

[0064] As used herein, a singular expression may be intended to include the plural expression as well, unless the context clearly indicates otherwise.

[0065] In the following description of the embodiments, the terms "comprises", "including", "includes" and "having" are inclusive, and thus specify the presence of the described features, values, steps, operations, elements, components and / or combinations thereof, but do not exclude the presence or addition of one or more other features, values, steps, operations, elements, components and / or combinations thereof.

[0066] Reference Figure 1 According to an exemplary embodiment of the present invention, a regenerative braking control system for a vehicle includes a controller 1, a regenerative braking switch 3, an accelerator pedal sensor 5, a motor 7 and a reducer 9. The controller 1 is configured to execute a regenerative braking control method to be described below. The regenerative braking switch 3 is configured to provide a signal to the controller 1 indicating that a user has selected activation of a regenerative braking function of the vehicle. The accelerator pedal sensor 5 is configured to detect the release of the accelerator pedal and provide information related to the accelerator pedal to the controller 1. The motor 7 and the reducer 9 are controlled by the controller 1 and are configured to generate torque required by the vehicle.

[0067] That is, the regenerative braking switch 3 is set to be turned on by a user (such as a driver) to activate the regenerative braking control function of the vehicle, or turned off by the user, and only by turning on the regenerative braking switch 3, the controller 1 automatically executes the regenerative braking control method according to an exemplary embodiment of the present invention to be described below according to the driving conditions of the vehicle.

[0068] In addition, the regenerative braking control system according to an exemplary embodiment of the present invention may include a navigation system 11 and at least one of a front camera 13 or a front radio detection and ranging (RADAR) 15, wherein the navigation system 11 is configured to provide information related to a speed camera in front of the vehicle's driving road, and at least one of the front camera 13 or the front RADAR 15 is configured to detect information related to a leading vehicle in front of the vehicle's driving road.

[0069] Furthermore, information related to physical quantities regarding vehicle travel, such as vehicle speed and vehicle acceleration, is input to the controller 1 from various sensors (not shown) of the vehicle.

[0070] In addition, the regenerative braking control system according to the exemplary embodiment of the present invention may include a mode selection switch 17 configured to select determination of the target deceleration as a different value when a leading vehicle exists in front, which will be described below.

[0071] Reference Figure 2 and Figure 3 , a regenerative braking control method for a vehicle according to various exemplary embodiments of the present invention includes: in the on state of the regenerative braking switch 3, when the accelerator pedal is released, determining whether a specified downhill cruising condition is satisfied (S10), in the case where it is determined that the downhill cruising condition is satisfied, when there is no specified preparatory obstacle in front of the vehicle, setting the target deceleration of the vehicle to a specified deceleration for downhill cruising (S20), determining a torque required for the vehicle, that is, a torque required for the vehicle to decelerate at the target deceleration (S30), and preferentially utilizing regenerative braking to generate the torque required in the vehicle (S40).

[0072] That is, the controller 1 is configured to determine whether the downhill cruising condition is satisfied when it is confirmed based on the acceleration sensor 5 that the driver does not intend to accelerate the vehicle according to the release of the accelerator pedal in the on state of the regenerative brake switch 3 .

[0073] In the on state of the regenerative brake switch 3, the downhill cruising condition can be set to be satisfied when the current vehicle speed is greater than or equal to the target vehicle speed, which is determined by adding the specified pre-input vehicle speed value to the vehicle speed when the accelerator pedal is released.

[0074] Here, the pre-input vehicle speed value is an adjustment value, for example, it can be set to 1kph, 2kph, etc. The sum obtained by adding the pre-input vehicle speed value to the vehicle speed when the accelerator pedal is released becomes the target vehicle speed, and when the current vehicle speed is greater than or equal to the target vehicle speed, it is determined that the downhill cruising condition is met.

[0075] That is, when the vehicle speed is greater than or equal to the target vehicle speed (which is obtained by adding the margin of the pre-input vehicle speed to the vehicle speed at the time point when the driver releases the accelerator pedal), the downhill cruising condition is satisfied, and when there is no preparatory obstacle ahead, the vehicle automatically enters the downhill cruising state by setting the target deceleration of the vehicle to the deceleration for downhill cruising, and the vehicle is controlled by using the torque required for the vehicle to decelerate at the target deceleration.

[0076] Therefore, according to an exemplary embodiment of the present invention, assuming that the regenerative brake switch 3 is turned on, only when the driver releases the accelerator pedal, when it is determined that the downhill cruising condition is satisfied and there is no preparatory obstacle ahead, the vehicle automatically decelerates at the deceleration for downhill cruising, and therefore, the vehicle is in a downhill cruising state.

[0077] Of course, when the downhill cruising condition is not satisfied or in different driving situations (for example, when a preparatory obstacle exists), the controller 1 decelerates the vehicle at a different target deceleration, and in this case, the regenerative braking function of the vehicle is also preferentially utilized.

[0078] Therefore, unlike the conventional method, the regenerative braking control method according to the exemplary embodiment of the present invention does not require manipulation of a separate switch to enable the vehicle to cruise on a downhill road, thereby being able to increase the amount of regenerative braking of the vehicle and thus greatly contributing to the improvement of the energy efficiency of the vehicle while greatly improving the convenience of the driver.

[0079] When the downhill cruising condition is not satisfied, the target deceleration is set to the minimum value among the candidate decelerations determined according to the slope of the road on which the vehicle is traveling and the prepared obstacle.

[0080] Here, if Figure 2 In the exemplary embodiment shown, candidate deceleration rates may be determined prior to determining a downhill cruising condition.

[0081] For reference, as described below, the deceleration for coasting is preset to a constant value, and although Figure 2 It is shown that the process of setting the deceleration for coasting is performed when the accelerator pedal is released, but the process of setting the deceleration for coasting is actually omitted.

[0082] In addition, despite Figure 2It is shown that the process of determining the deceleration for downhill cruising, the process of determining the deceleration for a stationary obstacle, and the process of determining the deceleration for a moving obstacle are sequentially performed, but these processes may be performed simultaneously or in a different order.

[0083] When the road on which the vehicle travels is a flat road or an uphill road, one of the candidate decelerations is determined as the deceleration for coasting, and the deceleration for coasting is a predetermined constant value.

[0084] For example, the deceleration for coasting can be set to a specified constant value, such as 0.3m / s 2 or 0.4m / s 2 .

[0085] When the road on which the vehicle is traveling is a flat road or an uphill road, the target deceleration is set to a deceleration for coasting including the above-mentioned constant, the torque required to meet the target deceleration is determined, and the vehicle is controlled with the required torque.

[0086] The weight of commercial vehicles such as large trucks varies greatly, so it is basically necessary to compensate for the vehicle weight and road slope during the regenerative braking control of the vehicle, and in an exemplary embodiment of the present invention, compensation for the vehicle weight and road slope can be completed in the process of determining the required torque to achieve setting the vehicle's deceleration to a constant value.

[0087] Therefore, when the weight of the vehicle increases, the amount of regenerative braking of the vehicle increases, and when the vehicle travels on an uphill road, the amount of regenerative braking of the vehicle decreases.

[0088] When the road on which the vehicle is traveling is a downhill road, one of the candidate decelerations is determined as the deceleration for downhill cruising, and the deceleration for downhill cruising is set according to the difference between the target vehicle speed and the current vehicle speed.

[0089] For example, the deceleration for downhill cruising may be set proportional to the difference between the target vehicle speed and the current vehicle speed.

[0090] In this case, when the current vehicle speed becomes greater than the target vehicle speed, the deceleration for downhill cruising increases, so that as the vehicle speed increases on a downhill road, the vehicle decelerates at a deceleration that is as great as the increase in the difference between the target vehicle speed and the current vehicle speed, and therefore, the current vehicle speed can quickly converge on the target vehicle speed.

[0091] Here, the prepared obstacles in front of the vehicle include speed cameras, vehicles in front, and the like.

[0092] When the preliminary obstacle is a speed camera, one of the candidate decelerations is determined as the deceleration for the stationary obstacle.

[0093] The deceleration rate for a stationary obstacle is set to the deceleration required for the vehicle to reach the speed limit of the speed camera when the vehicle reaches the enforcement position of the speed camera.

[0094] That is, the deceleration rate for a stationary obstacle can be determined by the following equation:

[0095]

[0096] a cam : deceleration for stationary obstacles,

[0097] v cam : Speed ​​limit of speed camera,

[0098] v cur : Current vehicle speed,

[0099] d cam : The distance from the vehicle’s current position to the speed camera,

[0100] d min : Minimum distance to prevent division by zero.

[0101] That is, when there is a speed camera ahead of the road on which the vehicle is traveling, the controller 1 (which obtains information related to the speed camera from a device such as the navigation system 11) is configured to determine the deceleration for the stationary obstacle through the above equation, and the controller 1 is configured to determine the required torque and preferentially utilize the regenerative braking of the vehicle to meet the required torque, so that when the vehicle reaches the execution position of the speed camera, the regenerative braking can be performed to the maximum extent possible while decelerating the vehicle so as not to exceed the speed limit.

[0102] When the preliminary obstacle is a preceding vehicle, one of the candidate decelerations is determined as the deceleration for moving the obstacle.

[0103] The deceleration for moving the obstacle is set to the deceleration required to keep the vehicle at an appropriate inter-vehicle distance from the vehicle ahead.

[0104] In an exemplary embodiment of the present invention, the deceleration for moving the obstacle may be one selected from a deceleration for moving the obstacle based on a first mode that is advantageous for maintaining an appropriate inter-vehicle distance with the preceding vehicle during braking of the preceding vehicle, and a deceleration for moving the obstacle based on a second mode that is advantageous for maintaining an appropriate inter-vehicle distance with the preceding vehicle during cruising of the preceding vehicle.

[0105] That is, the deceleration rate for moving the obstacle can be determined by the following equation:

[0106] a ref =β×a ctg +(1-β)×a ca ,

[0107]

[0108] In the first mode,

[0109] In the second mode,

[0110] a ref : deceleration used for moving obstacles,

[0111] β: Mixing ratio (adjustment value based on relative speed and relative distance), where relative speed refers to the speed difference between the vehicle and the vehicle in front, and relative distance refers to the distance between the vehicle and the vehicle in front.

[0112] h: time gap constant in constant time gap control,

[0113] λ: sliding gradient (as the sliding gradient increases, the distance control becomes faster),

[0114] v ego : The speed of the vehicle,

[0115] d min : The minimum distance to be maintained,

[0116] d rel : distance to the vehicle ahead,

[0117] v rel : relative speed,

[0118] v front : The speed of the vehicle ahead,

[0119] D: Appropriate distance between vehicles.

[0120] Here, the appropriate inter-vehicle distance D can be determined from a map indicating the inter-vehicle distance based on the current vehicle speed and the relative speed.

[0121] Of course, this map is pre-designed through extensive experimentation and analysis, and Figure 4 As shown, a single map may be provided, or a plurality of maps or a three-dimensional map may be provided so that the user can select a desired map to set the appropriate inter-vehicle distance to a longer or shorter distance even at the same current vehicle speed and relative speed.

[0122] When there is a leading vehicle on the road on which the vehicle is traveling, the controller 1 (which obtains information related to the leading vehicle from a device such as the front camera 13 or the front RADAR 15) is configured to determine the deceleration for moving the obstacle through the above equation, and the controller 1 is configured to determine the required torque and preferentially utilize the regenerative braking of the vehicle to meet the required torque, so that the regenerative braking can be performed to the maximum extent possible while decelerating the vehicle to maintain an appropriate vehicle-to-vehicle distance with the leading vehicle.

[0123] Here, when using a in the first mode ca Determine the deceleration a used to move the obstacle ref When the deceleration a is used to move the obstacle ref becomes a value based on the first mode, when using a in the second mode ca Determine the deceleration a used to move the obstacle ref When the deceleration a is used to move the obstacle ref Becomes a value based on the second mode.

[0124] The deceleration for a moving obstacle based on the first mode is a deceleration determined assuming that the position of the leading vehicle is fixed, and since the inter-vehicle distance tends to increase as much as the moving distance of the leading vehicle, it is beneficial to maintain the inter-vehicle distance during braking of the leading vehicle.

[0125] On the other hand, the deceleration for moving the obstacle based on the second pattern is a deceleration determined on the assumption that the leading vehicle is cruising, and is advantageous for maintaining a desired inter-vehicle distance during cruising of the leading vehicle.

[0126] In an exemplary embodiment of the present invention, a mode selection switch 17 is provided to enable a user to select one of the first mode and the second mode, so that the deceleration for moving the obstacle is determined and applied based on the first mode, or determined and applied based on the second mode, thereby being able to meet more different user needs.

[0127] When the downhill cruising condition is met but there is a preparatory obstacle ahead, the target deceleration is set to the minimum value among the above candidate decelerations.

[0128] That is, in a case where the downhill cruising condition is satisfied but there is a speed camera or a leading vehicle ahead, so that it is difficult for the vehicle to simply cruise on the downhill road, the controller 1 sets the target deceleration to the minimum value among the above-mentioned candidate decelerations, thereby enabling the vehicle to perform regenerative braking to the maximum extent possible while decelerating the vehicle while complying with the speed limit imposed by the speed camera or maintaining the desired vehicle-to-vehicle distance with the leading vehicle.

[0129] The required torque may be determined by adding the slope compensation torque, the air resistance compensation torque, and the rolling resistance compensation torque to a reference torque obtained by multiplying the target deceleration by the vehicle weight and the dynamic load radius of the tire.

[0130] This determination of the required torque may be referred to as open-loop control based on vehicle dynamics, and in this case, the slope compensation torque, air resistance compensation torque, and rolling resistance compensation torque are typically obtained based on vehicle dynamics, so a detailed description of their determination methods will be omitted.

[0131] Otherwise, the required torque may be determined by adding the slope compensation torque and the feedback compensation torque to a reference torque obtained by multiplying the target deceleration by the vehicle weight and the dynamic load radius of the tire.

[0132] This determination of the required torque may be referred to as feedback control (configured to track a target deceleration).

[0133] Here, the feedback compensation torque can be determined by the following equation:

[0134]

[0135] T fb : Feedback compensation torque,

[0136] T mot : Motor torque,

[0137] T rtd : Reducer torque,

[0138] r: dynamic load radius of the tire,

[0139] Estimated vehicle weight,

[0140] a veh : The current acceleration of the vehicle.

[0141] That is, the motor torque and the reducer torque may be torques that the controller 1 sends instructions to the motor 7 and the reducer 9. The torque may be determined based on the current acceleration of the vehicle, and thus the feedback compensation torque may be the difference between the command value and the result value.

[0142] While generating the torque required in the vehicle, when the vehicle speed is reduced to or less than a designated transition speed, the regenerative braking torque may be controlled to be gradually replaced by the retarder torque.

[0143] For example, in order to ensure the durability of the transmission due to the characteristics of the transmission used in the vehicle, regenerative braking by the motor 7 can be prohibited at a specific lower limit of the vehicle speed limit, and in view of this, when the vehicle speed is reduced to a conversion speed (the conversion speed is set to be slightly higher or lower than the lower limit of the vehicle speed limit), the regenerative braking torque generated by the motor 7 can be gradually replaced by the retarder torque, so that at the lower limit of the vehicle speed limit or lower, the motor 7 does not perform regenerative braking, thereby preventing the durability of the vehicle from being reduced.

[0144] That is, for example, assuming that the lower limit of the vehicle speed limit is 20 kph, the conversion speed can be set to 23 kph (which is slightly higher than the lower limit of the vehicle speed limit), and as the regenerative braking according to the exemplary embodiment of the present invention is performed, when the vehicle speed is reduced to 23 kph, the regenerative braking torque is gradually replaced by the retarder torque, and when the vehicle speed becomes 20 kph, the regenerative braking torque becomes 0 to prevent the durability of the vehicle's transmission from being reduced, etc.

[0145] It is obvious from the above description that in the regenerative braking control method of a vehicle according to an exemplary embodiment of the present invention, the regenerative braking amount suitable for the vehicle's driving conditions can be automatically controlled, thereby greatly improving the vehicle's energy efficiency while improving driving convenience by minimizing the driver's manipulation of the regenerative braking.

[0146] In addition, terms related to control devices such as "controller", "control device", "control unit", "control means", "control module" or "server" refer to hardware devices including a memory and a processor, and the processor is configured to execute one or more steps interpreted as an algorithm structure. The memory stores the algorithm steps, and the processor executes the algorithm steps to perform one or more processes of the method according to various exemplary embodiments of the present invention. The control device according to the exemplary embodiment of the present invention can be implemented by a non-volatile memory and a processor, the non-volatile memory is configured to store algorithms for controlling the operation of various components of the vehicle or data about software instructions for executing the algorithm, and the processor is configured to perform the above-mentioned operations using data stored in the memory. The memory and the processor can be separate chips. Alternatively, the memory and the processor can be integrated in a single chip. The processor can be implemented as one or more processors. The processor may include various logic circuits and operation circuits, can be configured to process data according to a program provided by the memory, and can be configured to generate a control signal according to the processing result.

[0147] The control device may be at least one microprocessor operated by a predetermined program, which may include a series of instructions for executing the methods included in the above-described various exemplary embodiments of the present invention.

[0148] The above invention may also be embodied as a computer-readable code on a computer-readable recording medium. A computer-readable recording medium is any data storage device that can store data that can be subsequently read by a computer system and can store and execute data that can be subsequently read by a computer system. Examples of computer-readable recording media include: a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a read-only memory (ROM), a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, as well as an implementation of a carrier wave (e.g., transmitted over the Internet). Examples of program instructions include machine language codes such as those generated by a compiler and high-level language codes that can be executed by a computer using an interpreter, etc.

[0149] In various exemplary embodiments of the present invention, each of the above operations may be performed by a control device, and the control device may be configured as a plurality of control devices or an integrated single control device.

[0150] In various exemplary embodiments of the present invention, the memory and the processor may be provided as one chip, or provided as separate chips.

[0151] In various exemplary embodiments of the present invention, the scope of the present invention includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) for enabling the steps of methods according to the various embodiments to be executed on a device or computer, and non-transitory computer-readable media storing such software or instructions and capable of being executed on a device or computer.

[0152] In various exemplary embodiments of the present invention, the control device may be implemented in the form of hardware or software, or may be implemented in a combination of hardware and software.

[0153] Furthermore, terms such as “unit”, “module” and the like included in the specification refer to a unit for processing at least one function or operation, and the unit may be implemented by hardware, software or a combination thereof.

[0154] For convenience of explanation and precise definition of the appended claims, the terms "above", "below", "inside", "outside", "up", "down", "upward", "downward", "front", "rear", "back", "inside", "outside", "inwardly", "outwardly", "inside", "outside", "inner", "external", "front" and "rear" are used to describe features of the exemplary embodiments with reference to the positions of such features as shown in the accompanying drawings. It will be further understood that the term "connect" or its derivatives refer to both direct and indirect connections.

[0155] The term "and / or" may include a combination of a plurality of associated listed items or any one of a plurality of associated listed items. For example, "A and / or B" includes all three situations, such as "A", "B" and "A and B".

[0156] In this specification, unless otherwise stated, a singular expression includes a plural expression unless the context clearly indicates otherwise.

[0157] In an exemplary embodiment of the present invention, “at least one of A and B” may mean “at least one of A or B” or “at least one of a combination of at least one of A and B”. Furthermore, “one or more of A and B” may mean “one or more of A or B” or “one or more of a combination of one or more of A and B”.

[0158] In the exemplary embodiments of the present invention, it should be understood that terms such as "including" or "having" are intended to indicate the presence of the features, quantities, steps, operations, elements, parts, or a combination thereof described in the specification, and do not exclude the possibility of adding or existing one or more other features, quantities, steps, operations, elements, parts, or a combination thereof.

[0159] The description presented above of the specific exemplary embodiments of the present invention is for the purpose of illustration and description. The foregoing description is not intended to be exhaustive, or to limit the present invention to the precise form disclosed, and it is apparent that several modifications and variations are possible according to the above teachings. Exemplary embodiments are selected and described to explain the specific principles of the present invention and their practical applications, so that other technical personnel in the art can utilize and implement various exemplary embodiments of the present invention and various alternatives and modifications thereof. The scope of the present invention is intended to be limited by the appended claims and their equivalents.

Claims

1. A regenerative braking control method for a vehicle, the method comprising: In the on state of the regenerative brake switch, in response to the accelerator pedal being released, the controller determines whether a specified downhill cruising condition is satisfied; When it is determined that the downhill cruising condition is satisfied, in response to the absence of a designated preparatory obstacle in front of the vehicle, setting the target deceleration of the vehicle to a designated deceleration for downhill cruising; determining the torque required to decelerate the vehicle at a target deceleration rate; Regenerative braking is used to generate the required torque in the vehicle.

2. The regenerative braking control method for a vehicle according to claim 1, wherein: In the on state of the regenerative brake switch, the controller determines that the downhill cruising condition is satisfied in response to the current vehicle speed being greater than or equal to a target vehicle speed determined by adding a specified pre-input vehicle speed value to the vehicle speed in response to the accelerator pedal being released.

3. The regenerative braking control method for a vehicle according to claim 2, wherein: When it is determined that the downhill cruising condition is not satisfied, the target deceleration is set to a minimum value among candidate decelerations determined according to the slope of the road on which the vehicle is traveling and the prepared obstacle.

4. The regenerative braking control method of a vehicle according to claim 3, wherein: In response to a road on which the vehicle is traveling being a flat road or an uphill road, determining one of the candidate decelerations as a deceleration for coasting; The deceleration for coasting is a predetermined constant value.

5. The regenerative braking control method for a vehicle according to claim 3, wherein: In response to a road on which the vehicle is traveling being a downhill road, determining one of the candidate decelerations as a deceleration for downhill cruising; The deceleration for downhill cruising is set according to the difference between the target vehicle speed and the current vehicle speed.

6. The regenerative braking control method for a vehicle according to claim 3, wherein: In response to the preliminary obstacle being a speed camera, determining one of the candidate decelerations as a deceleration for a stationary obstacle; The deceleration rate for a stationary obstacle is set to be the deceleration rate required for the vehicle to reach the speed limit of the speed camera in response to the vehicle reaching the execution position of the speed camera.

7. The regenerative braking control method for a vehicle according to claim 6, wherein: The deceleration rate for a stationary obstacle is determined by the following equation: in, a cam : deceleration for stationary obstacles; v cam : Speed ​​limit of speed camera; v cur : Current vehicle speed; d cam : the distance from the vehicle’s current position to the speed camera; and d min : Minimum distance to prevent division by zero.

8. The regenerative braking control method for a vehicle according to claim 3, wherein: In response to the prepared obstacle being a leading vehicle, determining one of the candidate decelerations as a deceleration for moving the obstacle; The deceleration for moving the obstacle is set to the deceleration required to keep the vehicle at an appropriate vehicle-to-vehicle distance from the vehicle ahead.

9. The regenerative braking control method for a vehicle according to claim 8, wherein: The deceleration for moving the obstacle is one selected from a deceleration for moving the obstacle based on a first mode configured to facilitate maintaining an appropriate inter-vehicle distance with the leading vehicle during braking of the leading vehicle and a deceleration for moving the obstacle based on a second mode configured to facilitate maintaining an appropriate inter-vehicle distance with the leading vehicle during cruising of the leading vehicle.

10. The regenerative braking control method for a vehicle according to claim 9, wherein: The deceleration rate used to move the obstacle is determined by the following equation: a ref =β×a ctg +(1-β)×a ca , In mode 1, In mode 2, in, a ref : deceleration used to move obstacles; β: Mixing ratio, which is an adjustment value based on relative speed and relative distance; h: time gap constant in constant time gap control; λ: sliding gradient. As the sliding gradient increases, the distance control becomes faster. v ego : The speed of the vehicle; d min : The minimum distance to be maintained; d rel : The distance to the vehicle ahead; v rel : relative speed; v front : the speed of the vehicle ahead; and D: Appropriate distance between vehicles.

11. The regenerative braking control method for a vehicle according to claim 10, wherein: The appropriate inter-vehicle distance D is determined from a map that indicates the inter-vehicle distance based on the current vehicle speed and the relative speed of the vehicles.

12. The regenerative braking control method for a vehicle according to claim 3, wherein: When it is determined that the downhill cruising condition is satisfied, in response to the presence of a preparatory obstacle ahead, the target deceleration is set to the minimum value among the candidate decelerations.

13. The regenerative braking control method for a vehicle according to claim 1, wherein: The required torque is determined by adding the slope compensation torque, the air resistance compensation torque, and the rolling resistance compensation torque to a reference torque obtained by multiplying the target deceleration by the vehicle weight and the dynamic load radius of the tire.

14. The vehicle regenerative braking control method according to claim 1, wherein: The required torque is determined by adding the slope compensation torque and the feedback compensation torque to a reference torque obtained by multiplying the target deceleration by the vehicle weight and the dynamic load radius of the tire.

15. The regenerative braking control method for a vehicle according to claim 14, wherein: The feedback compensation torque is determined by the following equation: in, T fb : Feedback compensation torque; T mot : Motor torque; T rtd : reducer torque; r: dynamic load radius of the tire; Estimated vehicle weight; and a veh : The current acceleration of the vehicle.

16. The regenerative braking control method of a vehicle according to claim 1, wherein: In generating the required torque in the vehicle, the regenerative braking torque is replaced by the retarder torque in response to the vehicle speed decreasing to or less than the designated transition speed.

17. A regenerative braking control system for a vehicle, the system comprising: A controller configured to execute the regenerative braking control method according to claim 1; a regenerative braking switch configured to provide a signal to the controller indicative of a user selection to activate a regenerative braking function of the vehicle; an accelerator pedal sensor configured to detect a release of the accelerator pedal and provide information related to the accelerator pedal to the controller; as well as The motor and the reducer are controlled by a controller and configured to generate a torque required in the vehicle.

18. The regenerative braking control system of a vehicle according to claim 17, further comprising: a navigation system configured to provide information related to a speed camera ahead of a road on which the vehicle is traveling; and At least one of a front camera or a front radio detection and ranging, the front camera or the front radio detection and ranging being configured to detect information related to a leading vehicle ahead of a path of travel of the vehicle.

19. The regenerative braking control system of a vehicle according to claim 17, further comprising a mode selection switch configured to select the target deceleration to be determined as a different value in response to the presence of a preceding vehicle ahead.

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