Control method and system for generating virtual driving feel in electric vehicle

Abstract

The present invention relates to a control device and method for an electric vehicle for implementing a virtual drivetrain sensibility, and the main purpose is to provide a control device and method for an electric vehicle capable of implementing and providing a differentiated driving sensibility in an electric vehicle that can be felt in other drivetrains, such as the drivetrain of an internal combustion engine vehicle. To achieve the above objective, a control method for an electric vehicle for implementing a virtual drivetrain sensibility is disclosed, comprising: a step of determining a basic torque command for controlling the operation of a drive motor from vehicle driving information collected during vehicle driving in a controller; a step of determining a virtual drivetrain torque command, which is a modified torque command for implementing a virtual drivetrain sensibility, from the determined basic torque command using a pre-set virtual drivetrain model in the controller; and a step of controlling the torque of the drive motor in accordance with the determined virtual drivetrain torque command in the controller.

Description

Technology Field

[0001] The present invention relates to a control device and method for an electric vehicle, and more specifically, to a control device and method capable of generating and providing to a driver a differentiated virtual driving sensation in an electric vehicle that can be felt in other powertrains, such as the powertrain of an internal combustion engine vehicle. Background Technology

[0003] As is well known, an electric vehicle (EV) is a vehicle that runs using a motor as its driving force.

[0004] The powertrain of an electric vehicle includes a battery that supplies power to drive a motor, an inverter connected to the battery to drive and control the motor, a motor connected to the battery to enable charging and discharging through the inverter, and a reduction gear that reduces the rotational force of the motor and transmits it to the drive wheels.

[0005] Here, the inverter converts the direct current (DC) supplied from the battery into alternating current (AC) when the motor is driven and applies it to the motor through the power cable, and when the motor is regenerated, it converts the alternating current (AC) generated by the motor operating as a generator into direct current (DC) and supplies it to the battery, thereby charging the battery.

[0006] Unlike conventional internal combustion engine vehicles, standard electric vehicles do not use multi-stage transmissions; instead, a reduction gear using a fixed gear ratio is placed between the motor and the drive wheels.

[0007] This is because, unlike internal combustion engines which have a wide distribution range of energy efficiency depending on the operating point and can only provide high torque in the high-speed region, motors have a relatively small difference in efficiency with respect to the operating point, and low-speed high torque can be achieved solely through the individual characteristics of the motor.

[0008] In electric vehicles, due to the characteristics of the drivetrain, unique vibration characteristics generated by torsional dampers or dual mass flywheels used in the drivetrains of internal combustion engine vehicles cannot occur.

[0009] While the absence of vibration during driving clearly offers an advantageous environment in that it provides seamless and smooth drivability, depending on the driver's preferences or the vehicle's sporty nature, it may also be necessary to provide a sensation with added vibration for an enjoyable driving experience. The problem to be solved

[0011] Accordingly, the present invention was created to solve the above-mentioned problems, and aims to provide a control device and method for an electric vehicle that can virtually implement and simulate various features that other drive systems, such as the drive system of an internal combustion engine vehicle, can provide by utilizing a motor in the electric vehicle according to the driver's requirements, and enables the driver to experience the driving sensations that could be felt in other drive systems in the electric vehicle.

[0012] The objectives of the present invention are not limited to those mentioned above, and other unmentioned objectives will be clearly understood by those skilled in the art to which the present invention pertains (hereinafter referred to as "skilled in the art") from the description below. means of solving the problem

[0014] To achieve the above objective, according to one aspect of the present invention, a control method for an electric vehicle for implementing a virtual drivetrain sensibility is provided, comprising: a step of determining a basic torque command for controlling the operation of a drive motor from vehicle driving information collected during vehicle driving in a controller; a step of determining a virtual drivetrain torque command, which is a modified torque command for implementing a virtual drivetrain sensibility, from the determined basic torque command using a virtual drivetrain model preset in the controller; and a step of controlling the torque of a drive motor according to the determined virtual drivetrain torque command in the controller.

[0015] Here, the control method of an electric vehicle according to an embodiment of the present invention may further include a step of changing the value of a predetermined driver setting variable within a virtual drivetrain model used to determine a virtual drivetrain torque command from a basic torque command according to a driver's change input in a controller.

[0016] According to another aspect of the present invention, a control device for an electric vehicle for implementing a virtual drivetrain sensibility is provided, comprising: a first controller that generates and outputs a virtual drivetrain torque command; and a first controller that controls the torque of a drive motor according to the virtual drivetrain torque command output from the first controller, wherein the first controller comprises: a basic torque command generating unit that determines a basic torque command for controlling the operation of a drive motor from vehicle driving information collected during vehicle driving; and a virtual drivetrain mode controlling unit that determines a virtual drivetrain torque command, which is a modified torque command for implementing a virtual drivetrain sensibility, from a basic torque command determined by the basic torque command generating unit using the virtual drivetrain model in a state where the virtual drivetrain model is preset.

[0017] Here, the control device of an electric vehicle according to an embodiment of the present invention may further include an interface unit configured to allow a driver to change and input the value of a predetermined driver setting variable within the virtual drivetrain model of the virtual drivetrain mode control unit. Effects of the invention

[0019] Thus, according to the control device and method of an electric vehicle of the present invention, various features that can be provided by other drive systems, such as the drive system of an internal combustion engine vehicle, can be virtually implemented and simulated by using a motor in the electric vehicle according to the driver's request.

[0020] Ultimately, drivers can experience the driving sensations they could feel in other powertrains within their own vehicles, thereby enabling the improvement of the marketability of electric vehicles.

[0021] In addition, drivers can freely change and adjust variables related to the creation and implementation of virtual drivetrain sensations so that they can receive the virtual drivetrain sensation they prefer.

[0022] As a result, drivers can receive a virtual powertrain sensation generated by variable values ​​they have changed and adjusted, enabling the personalization and differentiation of powertrain sensations in electric vehicles. Brief explanation of the drawing

[0024] FIG. 1 is a block diagram showing the configuration of a device for controlling an electric vehicle according to the present invention. FIG. 2 is a block diagram showing the state in which a corrected torque command is generated from a basic torque command using a virtual drivetrain model in the present invention. Figure 3 is a flowchart illustrating the process of performing a virtual drive system mode in the present invention. FIGS. 4 to 6 are drawings illustrating examples of torque command personalization and modification in the implementation of a virtual drivetrain sensibility according to the present invention. FIG. 7 is a block diagram showing an example of a method for controlling amplitude in the present invention. FIG. 8 is a diagram showing examples of various torque shapes according to the set values ​​of the natural vibration frequency and damping rate in the present invention. Specific details for implementing the invention

[0025] The specific structural or functional descriptions presented in the embodiments of the invention are merely illustrative for the purpose of explaining embodiments according to the concept of the invention, and embodiments according to the concept of the invention may be implemented in various forms. Furthermore, it should not be interpreted as being limited to the embodiments described herein, but should be understood to include all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0026] Meanwhile, in the present invention, terms such as "first" and / or "second" may be used to describe various components, but said components are not limited to said terms. For the sole purpose of distinguishing one component from other components, for example, without departing from the scope of rights according to the concept of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component.

[0027] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. Conversely, when it is stated that one component is "directly connected" or "directly in contact" with another component, it should be understood that there are no other components in between. Other expressions used to describe the relationship between components, such as "between" and "exactly between," or "adjacent to" and "directly adjacent to," should be interpreted in the same way.

[0028] Throughout the specification, identical reference numbers denote identical components. The terms used in this specification are for describing embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used in this specification, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0030] The present invention relates to a control device and method for an electric vehicle for implementing a virtual drivetrain sensation, and more specifically, to a control device and method for an electric vehicle capable of implementing and providing a differentiated virtual driving sensation that can be felt in other drivetrains.

[0031] More specifically, the present invention aims to provide a control device and method that enable a driver to virtually experience the driving sensation of other powertrains, such as the powertrain of an internal combustion engine vehicle, by using a drive motor in an electric vehicle according to the driver's requirements to virtually implement and simulate various features provided by other powertrains.

[0032] If torque capable of virtually implementing and simulating various powertrain characteristics according to driver demands can be generated in an electric vehicle, it is possible to implement a function that allows drivers to virtually experience diverse driving sensations in their vehicle without the need to replace it, thereby enhancing the marketability of electric vehicles and enabling differentiation.

[0033] Furthermore, if the driving sensations of different powertrains in electric vehicles are virtually provided to drivers who prioritize driving feel, tailored to their individual preferences, it not only highlights the unique fun elements of electric vehicles but also enables powertrain personalization that differentiates virtual powertrain sensations according to the driver.

[0034] In conventional internal combustion engine vehicles, there were limitations in implementing personalization that differentiates the vehicle's powertrain feel according to the driver due to reasons such as fuel efficiency and exhaust gas regulations. However, in electric vehicles, exhaust gas regulations do not exist, and since the impact of powertrain feel personalization on electric efficiency is significantly smaller than its impact on fuel efficiency in internal combustion engines, it is possible to actively personalize virtual powertrain feel, thereby improving the vehicle's emotional quality.

[0035] Accordingly, the present invention discloses a control device and method for an electric vehicle that can provide a differentiated driving sensation to the driver by establishing a virtual drivetrain model and implementing the characteristics of other drivetrains in the electric vehicle based on motor torque control.

[0036] In particular, the present invention discloses a control device and method for implementing a virtual drivetrain sensibility of an electric vehicle, wherein the driver can directly and freely change and adjust model setting variable values ​​(which are driver setting variable values ​​described below) related to the generation and implementation of the virtual drivetrain sensibility, so that the driver can receive the virtual drivetrain sensibility and features preferred by the driver.

[0037] In the following description, the motor refers to a drive motor that drives a vehicle, and the vehicle to be controlled in the present invention may be an electric vehicle equipped with a reduction gear and lacking an internal combustion engine (conventional engine) and a multi-stage transmission.

[0038] In the present invention, the term "drivetrain sensation" or "drivetrain driving sensation" may include vibrations of the drivetrain that a driver can feel while driving, depending on the control and driving state of the drivetrain in the vehicle.

[0039] In the present invention, vibration of the drive system may refer to vibration (variation) of motor torque (driving force) that can be felt by the driver, and if there is vibration of motor torque during driving, the driver may feel it as vibration of the vehicle. In order to implement such vibration of the drive system, it is possible to generate and apply a motor torque command that includes a vibration component.

[0040] That is, as described below, a virtual drive system torque command having a value that changes into a vibration form while having vibration characteristics of a predetermined frequency, damping rate, and amplitude is generated and applied, and by controlling the torque output of the drive motor according to the virtual drive system torque command, a desired virtual drive system vibration can be produced.

[0041] Furthermore, personalizing the drivetrain feel means allowing the driver to directly change and adjust the setting values ​​of variables related to the creation and implementation of the virtual drivetrain feel (driving feel), thereby enabling the creation and implementation of a personalized virtual drivetrain feel corresponding to the changed settings.

[0042] Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings.

[0043] FIG. 1 is a block diagram showing the configuration of a device for controlling an electric vehicle according to the present invention, and FIG. 2 is a block diagram showing the state in which a modified torque command is generated from a basic torque command using a virtual drivetrain model in the present invention. In addition, FIG. 3 is a flowchart showing the process of performing a virtual drivetrain mode in the present invention.

[0044] A control method for an electric vehicle according to the present invention includes a process in which a driver directly changes a variable setting value (driver setting variable value) of a virtual drivetrain model while the virtual drivetrain model for generating and implementing a virtual drivetrain sensibility is established in a controller, and a control process for operating a virtual drivetrain mode that virtually generates and implements the driving sensibility of another drivetrain (virtual drivetrain sensibility) using the virtual drivetrain model during vehicle driving.

[0045] In the present invention, the virtual drivetrain model is configured to allow the driver to adjust and change the values ​​of model setting variables for personalization, that is, the values ​​of designated driver setting variables.

[0046] In addition, in the control process for operating the virtual drivetrain mode in the present invention, a motor control process is performed to generate a virtual drivetrain torque command through a virtual drivetrain model with modified variable setting values, and to generate and implement a personalized, differentiated virtual drivetrain sensation (vibration) preferred by the driver by controlling the motor torque according to the generated virtual drivetrain torque command.

[0047] Referring to FIG. 3, the control method according to the present invention is a control process for operating a virtual drivetrain mode, comprising: a step (S6) of determining whether the virtual drivetrain mode is turned on by a driver in a controller; a step of determining a basic torque command from vehicle driving information collected from a vehicle by a controller when the virtual drivetrain mode is turned on; a step of determining a modified final torque command (virtual drivetrain torque command) for implementing the virtual drivetrain by the determined basic torque command by a virtual drivetrain model that takes the basic torque command as input in the controller; and a step (S7) of controlling the operation of a motor, which is a driving device that drives the vehicle, according to the determined final torque command in the controller.

[0048] In addition, the control method according to the present invention may further include the step of changing the value of a designated driver setting variable in a virtual drivetrain model according to a change input from a driver in a controller. In an embodiment of the present invention, the step of changing the driver setting variable value may specifically include: a step of determining whether there is a change input from a driver to a driver setting variable value in a controller (S1); a step of performing a change to the driver setting variable value in a controller according to the driver input if there is a change input (S2); a step of determining whether the driver selected to save the changed driver setting variable value in a controller (S3); and a step of applying the changed driver setting variable value to a virtual drivetrain model in a controller if saving is selected (S5).

[0049] Once the driver setting variable value changed as described above is saved and applied to the virtual drivetrain model, the final torque command (virtual drivetrain torque command) modified from the basic torque command is determined using the virtual drivetrain model with the driver setting variable value changed during driving of the electric vehicle in the ON state of the virtual drivetrain mode, and the operation of the motor driving the vehicle is controlled according to the determined final torque command (see step S7).

[0050] Additionally, if there is no input to change the driver setting variable value in step S1, proceed to step S6, and if saving the driver setting variable value changed in step S3 is not selected, return the variable value to the previously saved value and proceed to step S6. If the function of the virtual drivetrain mode is off in step S6, the controller controls the operation of the motor according to the determined basic torque command (S8).

[0051] And, looking at the configuration of a control device that performs a motor control process for a virtual drive system mode according to the present invention, as shown in FIG. 1, the control device is configured to include an interface unit (11) provided so that a driver can select and input one of the on and off of the virtual drive system mode of the vehicle and change and input driver setting variable values ​​for personalization of the virtual drive system mode function; a driving information detection unit (12) that detects vehicle driving information; a first controller (20) that determines a basic torque command from the vehicle driving information detected by the driving information detection unit (12) and generates and outputs a virtual drive system torque command using a virtual drive system model from the determined basic torque command; and a second controller (30) that controls the operation of a drive device (41) according to the virtual drive system torque command output by the first controller (20).

[0052] Here, the first controller (20) may be configured to include a basic torque command generation unit (21) that determines a basic torque command from vehicle driving information collected from the vehicle, and a virtual drivetrain mode control unit (22) that generates and outputs a virtual drivetrain torque command using a virtual drivetrain model from the basic torque command determined by the basic torque command generation unit (21).

[0053] In the following description, the control entities are distinguished as a first controller (20) and a second controller (30); however, the control process according to the present invention may also be performed by a single integrated control element instead of multiple controllers. If the multiple controllers or the single integrated control element are collectively referred to as a controller, it can be understood that the control process according to the present invention is performed by this controller. That is, this controller may collectively refer to the first controller and the second controller.

[0054] In a control device that performs a control process according to the present invention, the interface unit (11) may be any means capable of enabling a driver to select the on and off of a virtual drivetrain mode in a vehicle and to change the driver setting variable value of a virtual drivetrain model by inputting a desired driver setting variable value for personalization, such as an operating device such as a button or switch provided in a vehicle, or an input device or touch screen of an ANV (Audio, Video, Navigation) system.

[0055] The above interface unit (11) can be connected to the first controller (20), and when the driver performs an on / off operation or a change operation of driver setting variable information, a signal corresponding to the operation can be input from the interface unit (11) to the first controller (20). Accordingly, the first controller (20) can recognize the on / off operation status of the virtual drive system mode by the driver and the change status of the driver setting variable information.

[0056] In the present invention, the operation and control process of a virtual drivetrain mode that generates and implements a virtual drivetrain sensation (which may be a virtual drivetrain vibration) through motor torque control during vehicle driving is executed only when the driver selects the virtual drivetrain mode on through the interface unit (11) (see step S6 of FIG. 3).

[0057] In addition, if the above-mentioned interface unit (11) is a vehicle input device provided in the vehicle, the driver can also perform operations to turn on and off the virtual drive system mode or to change driver setting variable information through a mobile device (not shown), instead of such a vehicle input device, although not shown in FIG. 1.

[0058] The above mobile device must be capable of being communicated to a device within a vehicle, such as a first controller (20), and for this purpose, an input / output communication interface (not shown) for communication connection between the mobile device and the first controller (20) is used.

[0059] The driving information detection unit (12) is a component that detects vehicle driving information necessary to generate a motor torque command in a vehicle, wherein the vehicle driving information may include driver's driving input information and vehicle status information.

[0060] In an embodiment of the present invention, the driving information detection unit (12) may include an accelerator pedal detection unit that detects accelerator pedal input information according to the driver's operation of the accelerator pedal, and a brake pedal detection unit that detects brake pedal input information according to the driver's operation of the brake pedal. In addition, the driving information detection unit (12) may further include a motor speed detection unit for detecting the rotational speed (hereinafter referred to as 'motor speed') of a motor, which is a driving device (41) that drives the vehicle.

[0061] Here, the accelerator pedal detection unit may be a conventional accelerator position sensor (APS) installed on the accelerator pedal that outputs an electrical signal according to the driver's accelerator pedal operation state. The brake pedal detection unit may be a conventional brake pedal sensor (BPS) installed on the brake pedal that outputs an electrical signal according to the driver's brake pedal operation state. Additionally, the motor speed detection unit may be a known resolver installed on the motor (drive motor) (41).

[0062] At this time, the driver's driving input information includes an accelerator pedal input value (APS value) detected by the accelerator pedal detection unit and a brake pedal input value (BPS value) detected by the brake pedal detection unit, and the vehicle status information includes a motor speed detected by the motor speed detection unit.

[0063] In addition, the driving information used to generate the basic torque command in the basic torque command generation unit (21) described later may further include vehicle speed as vehicle status information. In this case, the driving information detection unit (12) may further include a vehicle speed detection unit for detecting the driving speed of the vehicle, and the vehicle speed detection unit may be configured to include a wheel speed sensor installed on the driving wheel of the vehicle.

[0064] The above basic torque command may be a motor torque command determined and generated based on vehicle driving information collected while driving in a conventional electric vehicle, and the above basic torque command generating unit (21) may be a Vehicle Control Unit (VCU) or a part thereof that generates a motor torque command based on vehicle driving information in a conventional electric vehicle.

[0065] In addition, the virtual drivetrain mode control unit (22) is a novel component that determines, generates, and outputs a virtual drivetrain torque command from a basic torque command using a virtual drivetrain model in which setting variable information can be changed by the driver while receiving a basic torque command as input in the present invention, and this may be added as part of a vehicle controller (VCU) or provided as a control element separate from the vehicle controller.

[0066] The second controller (30) is a controller that controls the operation of the drive unit (41) by receiving the final torque command output from the first controller (20), that is, the virtual drive unit torque command determined and generated and output by the virtual drive unit mode control unit (22) of the first controller (20).

[0067] In the present invention, the driving device (41) is a motor (driving motor) that drives a vehicle, and the second controller (30) may be a known motor controller (Motor Control Unit, MCU) that drives the motor through an inverter in a conventional electric vehicle and controls the operation of the motor. The torque and rotational force output by the driving device (40) are transmitted to the driving wheel (43) through the reduction gear (42) as shown in FIG. 1.

[0068] Meanwhile, in the present invention, a virtual drivetrain model capable of determining and generating a virtual drivetrain torque command by inputting a basic torque command is pre-input and set in the virtual drivetrain mode control unit (22).

[0069] In this manner, when a virtual drivetrain model is set in the virtual drivetrain mode control unit (22), and a basic torque command is input from the basic torque command generation unit (21) to the virtual drivetrain mode control unit (22) during the operation of the virtual drivetrain mode, the virtual drivetrain model of the virtual drivetrain mode control unit (22) modifies the basic torque command according to driver setting variable information to generate a virtual drivetrain torque command.

[0070] Ultimately, the driving force generated in the vehicle during the operation of the virtual drivetrain mode is the driving force generated by the motor (41) operating according to the virtual drivetrain torque command rather than the basic torque command, and the driver can experience the virtual drivetrain sensation and characteristics through the driving force generated by the motor (41) according to the virtual drivetrain torque command.

[0071] In particular, in the virtual drivetrain model, the driver can adjust the driver setting variable value to their desired value, and the virtual drivetrain torque command is determined and output according to the driver setting variable value adjusted by the driver in the virtual drivetrain model.

[0072] Therefore, by adjusting the driving setting variable value by the driver, the driving force generated and output by the motor (41) can be differentiated even under the same vehicle driving conditions, and the personalization of the virtual driving system sensibility can be achieved, providing a differentiated virtual driving system sensibility and characteristics for each individual.

[0073] In an embodiment of the present invention, the driver setting variable information in the virtual drivetrain model is virtual drivetrain stiffness (spring rate, ) and virtual drivetrain damping amount (damping rate, ), and virtual drivetrain inertia (virtual drivetrain weight) (mass, It may include at least one or two of the following.

[0074] In addition, in an embodiment of the present invention, when implementing virtual drivetrain sensation is implementing drivetrain vibration through motor torque control, the driver setting variable information in the virtual drivetrain model is the resonance frequency of the virtual drivetrain torque (which is a command). ) and the damping ratio of virtual drivetrain torque It may include at least one or two of the amplitude (A) of the virtual drivetrain torque, and the amplitude of the virtual drivetrain torque.

[0075] The above-mentioned driver setting variable information is used to construct a virtual drivetrain model, and furthermore, during the operation of the virtual drivetrain mode, it is used to convert the basic torque command in the virtual drivetrain model into a virtual drivetrain torque command.

[0076] In addition, the driver setting variable value of the virtual drivetrain model can be adjusted by the driver to a desired value through the interface unit (11), and the virtual drivetrain torque command converted from the basic torque command changes according to the value adjusted by the driver. Therefore, if the motor (41) is controlled according to the converted virtual drivetrain torque command, a differentiated virtual drivetrain sensation can be provided.

[0077] FIG. 2 shows that in an embodiment of the present invention, the virtual drivetrain model of the virtual drivetrain mode control unit (22) generates and outputs a virtual drivetrain torque command, which is a modified torque command, by using the basic torque command generated and output by the basic torque command generation unit (21) as input.

[0078] Below, we will explain the virtual drive system model in more detail.

[0079] In the present invention, the virtual drivetrain model is pre-set in the virtual drivetrain mode control unit (22) for the operation of the virtual drivetrain mode, and is set to output a virtual drivetrain torque command with a basic torque command as input.

[0080] In addition, in the present invention, the virtual drivetrain model performs the role of converting a basic torque command without vibration components into a virtual drivetrain torque command including vibration components, and the aforementioned driver setting variable value is used in converting the basic torque command into a virtual drivetrain torque command in the virtual drivetrain model.

[0081] In conventional vehicles, driving force or torque control methods all aimed to eliminate vehicle vibration, but in the present invention, driving force or torque control is performed to add vibration in a desired manner.

[0082] In an embodiment of the present invention, a mass-spring-damper system model is basically used as the virtual drivetrain model. In an embodiment of the present invention, when a conventional mass-spring-damper system model is used as the virtual drivetrain model, a basic torque command (which is the input torque command of the model) is substituted and used as the input force in the mass-spring-damper system.

[0083] In addition, in an embodiment of the present invention, when a model of a conventional mass-spring-damper system is used as a virtual drive system model, the sum of the spring force and the damping force in the mass-spring-damper system becomes the virtual drive system torque command (modified torque command), which is the output torque command of the model.

[0084] Here, a model of a conventional mass-spring-damper system refers to a system in which the sum (or difference) of the spring force (the product of displacement and spring rate), the damping force (the product of velocity (derivative of displacement) and damping rate), and the input force is balanced with the product of inertia (weight) and acceleration (derivative of velocity), as shown in Equation (1) below.

[0085] The above system can be expressed mathematically as the following differential equation.

[0087] (1)

[0089] Here, is input force, is spring stiffness (spring rate), is the damping rate of the damper, class is the inertia (weight) and displacement of the mass, is speed, Each represents acceleration.

[0090] In the above formula is the smring force, represents damping force.

[0091] In addition, the output force is the sum of the spring force and the damping force ('output force = spring force + damping force'), the input force is the basic torque command, and the output force is the virtual drivetrain torque command.

[0092] In the virtual drive system model of the above equation (1) , , At least one or two of the above are driver setting variables in the embodiment of the present invention, which are variables that can be controlled by the driver, and in the present invention, the driver is enabled to control the above driver setting variable values ​​through the interface unit (11).

[0093] That is, the driver, through the interface unit (11), sets the driver setting variable, the virtual drivetrain stiffness (spring rate, ), virtual drivetrain damping amount (damping rate, ), virtual drivetrain inertia(mass, It is possible to adjust the values ​​of these variables, and by adjusting these variable values, the characteristics of the virtual drivetrain model can be changed, and the shape of the virtual drivetrain torque command that is modified and converted from the basic torque command can be changed.

[0094] , , Each is a virtual physical value, and the driver directly [uses] the virtual drivetrain model , , It is possible to adjust the values ​​of variables (direct parameters) such as [this]. However, as a slightly more intuitive personalization method, a feature may be provided that allows the characteristics of the virtual drive system model to be adjusted by adjusting the values ​​of derived parameters instead of adjusting virtual physical variables.

[0095] The derived parameter is the resonance frequency of the virtual drivetrain torque. ), damping ratio of virtual drivetrain torque (damping ratio, ), and the amplitude (A) of the virtual drivetrain torque can be defined as representative. The advantage of this method is that each derivation variable does not affect each other.

[0096] for example, Increasing the value not only speeds up the oscillation period Even though the value is fixed, they influence each other because there is an effect of weakening damping. However, by increasing the natural vibration frequency, it is possible to accelerate only the vibration period while maintaining the damping rate.

[0097] In an embodiment of the present invention, the natural vibration frequency (resonance frequency, of virtual drive system torque ) is a variable that determines the frequency of virtual drivetrain torque vibration, and the virtual drivetrain damping ratio (ζ) is a variable that determines the degree to which the vibration of the virtual drivetrain torque is damped and dissipated.

[0098] Furthermore, regarding the amplitude (A) of the virtual drivetrain torque in an embodiment of the present invention, first, the amplitude of the virtual drivetrain torque is a variable that determines the magnitude of torque vibration, and in a conventional mass-spring-damper system, the amplitude cannot be adjusted independently. This is because the amplitude is expressed as a function of frequency and damping rate.

[0099] Accordingly, the present invention provides a method for adjusting the amplitude. The method for adjusting only the amplitude A of the added vibration while maintaining the value of the input torque, which is the basic torque command, is as follows.

[0101] (2)

[0103] In the above equation (2) corresponds to spring force, and is the damping force. Here, the output torque, i.e., the modified and converted virtual drivetrain torque command, is given by Equation (3) below.

[0105] (3)

[0107] In the above equation (3) It becomes the basic torque command corresponding to the input force.

[0108] The above equation is expressed using derived parameters, through which the amplitude (A) is expressed as the natural vibration frequency ( ) and damping rate( It can be adjusted individually separately from ). Here, displacement ( The value serves as an intermediate variable for calculating output torque, and the output torque (virtual drivetrain torque command) is used for controlling the driving force of the actual vehicle.

[0109] FIGS. 4 to 6 illustrate examples of torque command personalization and modification in the implementation of a virtual drivetrain sensibility according to the present invention. In FIGS. 4 to 6, a virtual drivetrain torque command converted from the basic torque command using driver setting variable information is shown together with the basic torque command.

[0110] Figure 4 shows the virtual drivetrain natural vibration frequency (resonance frequency, ) high frequency (High ), medium frequency (Medium ), low frequency (Low It shows examples where the values ​​of ) are set differently.

[0111] Figure 5 shows the virtual drivetrain damping ratio as driver setting variable information, ) high damping rate (High ), Medium damping rate (Medium ), low frequency (Low It shows examples where the values ​​of ) are set differently.

[0112] Figure 6 shows an example in which the virtual drivetrain amplitude (A) is set differently as high amplitude (High A), medium amplitude (Medium A), and low amplitude (Low A) values ​​as driver setting variable information.

[0113] In addition to the method of defining Amplitude A as described above, other methods can be applied to obtain the final torque command by adjusting Amplitude A. Basically, the final modified virtual drivetrain torque command can be obtained by calculating the difference between the modified torque command obtained through the aforementioned virtual drivetrain model and the base torque command, multiplying this difference by the Amplitude setting value A (a driver-set variable), and then summing this result with the base torque command. In other words, this method calculates the difference between the input and output values ​​of the virtual drivetrain model, multiplies this by the Amplitude setting value A, sums the result to the input value, and uses the sum as the final torque command (final virtual drivetrain torque command).

[0114] In addition, another method of obtaining the final torque command by adjusting the amplitude A can be applied. There is a method in which the value of the output torque command (first modified torque command) obtained by using a model of a conventional mass-spring-damper system as a virtual drivetrain model is input again into the virtual drivetrain model, and the value of the output torque command obtained through the virtual drivetrain model is obtained as the value of the final torque command (which is the final virtual drivetrain torque command as the second modified torque command). That is, by using the virtual drivetrain model twice, a method as shown in FIG. 7 can be applied.

[0115] As shown in FIG. 7, a basic torque command (input torque command) is input into a virtual drivetrain model to obtain a first modified torque command, which is the output torque command. After applying a predetermined weight to the first modified torque command and the basic torque command, the sum of the values ​​is used as the input torque command for the second virtual drivetrain model. At this time, amplitude A can be used as the weight for the first modified torque command. Additionally, the larger the value of the set amplitude A, the greater the weight for the first modified torque command compared to the weight for the basic torque command can be set.

[0116] Meanwhile, in an embodiment of the present invention, a method for preventing signal divergence may be applied, as the output signal may diverge due to causes such as discretization errors or mathematical instability of the system caused by set values. To prevent this, ranges of personalized set values ​​that are free from the risk of divergence may be defined, and changes in set values ​​may be limited to within these ranges. That is, lower and upper limits are predetermined and applied to each set value.

[0117] Due to discrete errors, it is possible to prevent system signals from diverging even when setting values ​​within the allowable range are applied; divergence symptoms can be prevented by detecting signal overflow and reducing the setting values ​​based on it.

[0118] in other words, or A divergence state is determined if the absolute magnitude of the signal value is greater than a predefined threshold, if the + or - sign changes at every sample time, or if this phenomenon persists for a predetermined period. In the case where it is determined to be in a divergence state, the natural vibration frequency set by the driver or already set ( ) and damping rate( Decrease the value of ) relative to the value at the previous sample time using a defined method. Repeat the reduction action until the divergence state condition ends.

[0119] In addition, in an embodiment of the present invention, a method for resolving the drivetrain backlash problem when using a virtual drivetrain torque command may be applied. Near the point where the torque value switches between the driving direction and the regenerative direction (near zero torque), backlash shock may occur as the arrangement direction of the drivetrain gears changes. To prevent this, vibration can be eliminated only in a defined backlash section where backlash shock is likely to occur.

[0120] As one method for this purpose, a method of adjusting the amplitude A can be applied. When the basic torque command enters a predetermined backlash range, the amplitude A can be reduced to a value of 0, and when the basic torque command exits the backlash range, the reduced amplitude A can be returned to its original set value. During this process of reducing and returning the amplitude A, it is possible to apply a rate limit or a filter to the amplitude A being adjusted, and the virtual drivetrain torque command can be determined using the amplitude A to which the rate limit or filter has been applied.

[0121] In an embodiment of the present invention, to further explain the backlash section, shock due to gear backlash may occur in a drive system including a reduction gear at the point where the direction of the motor torque is switched. Therefore, the backlash section may be pre-set in the controller as a section of a predetermined torque range (torque band) that includes zero (0) torque and approximates this zero torque.

[0122] At this time, the backlash section consists of a negative (-) torque region and a positive (+) torque region distinguished based on zero (0) torque. That is, the backlash section can be described as a torque section where a predetermined negative (-) torque value is the minimum value and a predetermined positive (+) torque value is the maximum value. Additionally, the backlash section can be set according to the drivetrain rotational speed or torque region.

[0123] In the present invention, the switching of the direction of the motor torque means that the motor torque switches from a positive (+) value to a negative (-) value, or conversely, switches from a negative value to a positive value. Here, a positive (+) value of the motor torque refers to the driving torque, and a negative (-) value of the motor torque refers to the regenerative torque.

[0124] In addition, in embodiments of the present invention, a method using a transfer function model may be applied. Since a virtual mass-spring-damper system can be expressed in the form of a transfer function as a linear system, the entire virtual drivetrain model can be applied by converting it into a transfer function. As previously described, the input of the transfer function is a basic torque command, and the output is a virtual drivetrain torque command, which is a modified torque command. Since the method of converting a mass-spring-damper linear system into a transfer function is a well-known method, a detailed description is omitted in this specification.

[0125] FIG. 8 is a diagram showing examples of various torque shapes according to the set values ​​of the natural vibration frequency and damping rate in the present invention, and Example 1 shows an everyday driving and comfort mode that provides appropriate acceleration / deceleration responsiveness and smooth drivability.

[0126] Example 2 is an example that embodies the sensibility of a high-performance GT car (Grand Touring Car), providing drivability where fast responsiveness is important but there is no significant inconvenience even during long-distance travel. Example 3 is an example that embodies the sensibility of a sports car, providing immediate acceleration and deceleration responsiveness and an intuitive torsional feel of the drivetrain due to powerful torque output.

[0127] Example 4 is an example that implements the sensation of a large vehicle such as a bus, providing the sensation of low-frequency vibration due to large gear backlash and high inertia; Example 5 is an example that provides the sensation of smooth acceleration and deceleration without step, eliminating sharp driving inputs; and Example 6 is an example that provides the sensation of inducing infant sleep by continuously and smoothly swaying in the forward and backward directions while fully reflecting the driver's will.

[0128] In this way, according to the control method of the present invention described above, it becomes possible to virtually implement and simulate various features that other drive systems, such as the drive system of an internal combustion engine vehicle, can provide by using a motor in an electric vehicle according to the driver's request.

[0129] While vibrations can be generated by simply adding continuous vibration patterns determined by set values, such cases may result in unrealistic vibrations being transmitted to the driver. Therefore, the present invention utilizes a virtual drivetrain model to add vibration torque that reflects the driver's intention to accelerate or decelerate.

[0130] Ultimately, according to the present invention, it is possible to implement highly realistic vibration torque, so that the driver does not merely feel simple vibration but feels a driving sensation as if the actual vehicle's drivetrain has been modified through tuning, and it is possible to provide a unique vehicle product that allows the driver to experience not only their own vehicle's drivetrain but also the drivetrains of various other vehicle models.

[0132] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also included within the scope of the present invention. Explanation of the symbols

[0134] 11 : Interface section 12: Driving information detection unit 20: First controller 21: Basic Torque Command Generation Unit 22: Virtual Drive System Mode Control Unit 30 : Second controller 41 : Drive unit (motor) 42 : Reducer 43 : Drive wheel

Claims

Claim 1 A control method for an electric vehicle for implementing a virtual drivetrain sensibility, comprising: a step of determining a basic torque command for controlling the operation of a drive motor from vehicle driving information collected during vehicle driving in a controller; a step of determining a virtual drivetrain torque command, which is a modified torque command for implementing a virtual drivetrain sensibility, from the determined basic torque command using a virtual drivetrain model pre-set in the controller; and a step of controlling the torque of a drive motor according to the determined virtual drivetrain torque command in the controller, wherein the virtual drivetrain model is configured to allow adjustment and change of model setting variable values, so as to allow the generation of a virtual drivetrain torque command using the virtual drivetrain model in which the model setting variable values ​​have been adjusted and changed. Claim 2 A control method for an electric vehicle for implementing a virtual drivetrain sensibility according to claim 1, wherein the virtual drivetrain torque command is a motor torque command having a value that changes in a vibration form, wherein a vibration component is added to the basic torque command. Claim 3 A control method for an electric vehicle for implementing a virtual drivetrain sensitivity, characterized in that, in claim 1, the value of the model setting variable is the value of the driver setting variable, and the value of the driver setting variable determined within the virtual drivetrain model, which is used to determine the virtual drivetrain torque command from the basic torque command according to the driver's change input in the controller, is further included in the step of changing the value of the driver setting variable. Claim 4 A control method for an electric vehicle for implementing a virtual drivetrain sensibility according to claim 3, wherein the virtual drivetrain torque command is a motor torque command having a value that changes in a vibration form by adding a vibration component to the basic torque command, and the driver setting variable determined within the virtual drivetrain model includes at least one or two of the vibration frequency of the virtual drivetrain torque command, the damping rate of the virtual drivetrain torque command, and the amplitude of the virtual drivetrain torque command. Claim 5 A control method for an electric vehicle for implementing a virtual drivetrain sensation, characterized in that, in claim 4, a model of a mass-spring-damper system is used as the virtual drivetrain model in the controller. Claim 6 A control method for an electric vehicle for implementing a virtual drivetrain sensibility according to claim 4, wherein, in the step of determining the virtual drivetrain torque command, a torque command modified by the virtual drivetrain model is determined using the basic torque command as input, and the virtual drivetrain torque command is determined by the sum of the value obtained by multiplying the difference between the modified torque command and the basic torque command by the amplitude, which is the driver setting variable value, and the basic torque command. Claim 7 A control method for an electric vehicle for implementing a virtual drivetrain sensibility according to claim 4, wherein, in the step of determining the virtual drivetrain torque command, a first modified torque command modified by the virtual drivetrain model is determined using the basic torque command as input, a value is obtained by summing the values ​​after applying a predetermined weight to the first modified torque command and the basic torque command respectively, a second modified torque command modified by the virtual drivetrain model is determined as the virtual drivetrain torque command using the summed value as input, and the weight applied to the first modified torque command is the amplitude, which is the driver setting variable value. Claim 8 A control method for an electric vehicle for implementing a virtual drivetrain sensation according to claim 4, characterized in that, in the controller, when the basic torque command enters a preset backlash interval, the amplitude is reduced to a value of 0, and when the basic torque command exits the backlash interval, the amplitude is restored to a value set by the driver. Claim 9 A control method for an electric vehicle for implementing a virtual drivetrain sensation according to claim 8, wherein the backlash section is set as a torque range section that approximates a value of zero (0), and is characterized by being set as a torque section that sets a predetermined negative (-) torque value as the minimum value and a predetermined positive (+) torque value as the maximum value. Claim 10 In claim 4, a model of a mass-spring-damper system is used as the virtual drivetrain model in the controller, and in the model of the mass-spring-damper system, the virtual drivetrain torque command is ' It is determined by the value of ', where A is the amplitude of the virtual drivetrain torque command, A control method for an electric vehicle for implementing a virtual drivetrain sensibility characterized by being a basic torque command. Claim 11 A control method for an electric vehicle for implementing a virtual drivetrain sensation according to claim 3, wherein a model of a mass-spring-damper system is used as the virtual drivetrain model in the controller, and in the model of the mass-spring-damper system, the input force is the basic torque command and the output force, which is the sum of the spring force and the damping force, is the virtual drivetrain torque command. Claim 12 In claim 11, a mathematical formula representing a model of the mass-spring-damper system From, displacement( ) and spring stiffness( The product of ) is the above spring force, and the velocity, which is the derivative of the displacement ( ) and damping amount( The product of ) is the damping force, and the predetermined driver setting variable is the spring stiffness ( ) and damping amount( A control method for an electric vehicle for implementing a virtual drivetrain sensation, characterized by having at least one or two of ), and weight (m). Claim 13 A control device for an electric vehicle for implementing a virtual drivetrain sensibility, comprising: a first controller that generates and outputs a virtual drivetrain torque command; and a first controller that controls the torque of a drive motor according to the virtual drivetrain torque command output from the first controller, wherein the first controller comprises: a basic torque command generation unit that determines a basic torque command for controlling the operation of a drive motor from vehicle driving information collected during vehicle driving; and a virtual drivetrain mode control unit that determines a virtual drivetrain torque command, which is a modified torque command for implementing a virtual drivetrain sensibility, from a basic torque command determined by the basic torque command generation unit using the virtual drivetrain model in a state where the virtual drivetrain model is preset, and wherein the virtual drivetrain model is configured to adjust and change model setting variable values, so as to be able to generate a virtual drivetrain torque command using the virtual drivetrain model in which the model setting variable values ​​are adjusted and changed. Claim 14 A control device for an electric vehicle for implementing a virtual drivetrain sensibility according to claim 13, wherein the virtual drivetrain torque command is a motor torque command having a value that changes in a vibration form, wherein a vibration component is added to the basic torque command. Claim 15 A control device for an electric vehicle for implementing a virtual drivetrain sensibility according to claim 13, further comprising an interface unit configured to allow a driver to change and input the value of a driver setting variable within a virtual drivetrain model set in the virtual drivetrain mode control unit, wherein the value of the model setting variable is the value of the driver setting variable. Claim 16 A control device for an electric vehicle for implementing virtual drivetrain sensitivity according to claim 15, wherein the virtual drivetrain torque command is a motor torque command having a value that changes in a vibration form by adding a vibration component to the basic torque command, and the driver setting variable determined within the virtual drivetrain model includes at least one or two of the vibration frequency of the virtual drivetrain torque command, the damping rate of the virtual drivetrain torque command, and the amplitude of the virtual drivetrain torque command. Claim 17 A control device for an electric vehicle for implementing a virtual drivetrain sensation, characterized in that, in claim 16, a model of a mass-spring-damper system is used as the virtual drivetrain model. Claim 18 A control device for an electric vehicle for implementing a virtual drivetrain sensation according to claim 15, wherein a model of a mass-spring-damper system is used as the virtual drivetrain model, and in the model of the mass-spring-damper system, the input force is the basic torque command and the output force, which is the sum of the spring force and the damping force, is the virtual drivetrain torque command.

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