Method for implementing virtual internal combustion engine vibrations in electric vehicles

Abstract

A method for realizing virtual internal combustion engine vibration in an electric vehicle, comprising: collecting operating variable information for determining a torque command and realizing virtual internal combustion engine vibration, determining virtual internal combustion engine vibration characteristics based on the collected operating variable information, determining a vibration torque command having the determined virtual internal combustion engine vibration characteristics, based on a basic motor torque command determined by the collected operating variable information and preset backlash occurrence area information, correcting the vibration torque command by correcting the determined virtual internal combustion engine vibration characteristics and / or the value of the vibration torque command of the vibration torque command, and determining a final motor torque command using the basic motor torque command and the corrected vibration torque command.

Description

Technical Field

[0001] The present disclosure relates to a method for implementing virtual internal combustion engine vibrations in an electric vehicle. Background Art

[0002] As is known to all, an electric vehicle (EV) is a vehicle that travels using an electric motor. The driving system of an electric vehicle includes: a battery configured to provide electric power for driving the electric motor; an inverter connected to the battery and configured to drive and control the electric motor, which is connected to the battery to be charged and discharged through the inverter as a vehicle driving source; and a speed reducer configured to reduce the rotational force of the electric motor and transmit the rotational force to the driving wheels.

[0003] Here, the role of the inverter is to convert the direct current (DC) provided by the battery into alternating current (AC) so that the AC power can be applied to the motor through the cable when the motor is driven, and to convert the AC power generated by the motor into direct current and then provide the DC power to the battery so as to charge the battery when the motor is regenerated.

[0004] Unlike conventional internal combustion engine vehicles, conventional electric vehicles do not use a multi-speed transmission, but rather, a speed reducer using a fixed gear ratio is arranged between the motor and the drive wheels. This is because unlike an internal combustion engine (ICE), which can only provide high torque in a region with a wide energy efficiency distribution range and can provide high speed depending on the operating point, the motor has a relatively small inefficiency difference between operating points and can achieve high torque and low speed only with the characteristics of a single motor.

[0005] In addition, a vehicle equipped with a conventional drive system for an internal combustion engine requires an oscillation mechanism such as a torque converter or a clutch because of the characteristic that the internal combustion engine cannot be driven at a low speed, but since the drive system for an electric vehicle has the characteristic that the electric motor is easily driven at a low speed, the oscillation mechanism can be omitted. Due to the mechanical difference, the electric vehicle can have no interruption of operability caused by shifting and provide soft operability different from the internal combustion engine vehicle.

[0006] In addition, the main source of vibration in a vehicle equipped with a conventional drive system for an internal combustion engine is the engine (internal combustion engine). The vibration generated by the periodic explosive force of the engine in the starting state is transmitted to the vehicle body and passengers through the drive system, supports, etc. Vibration is often considered a negative factor that needs to be damped. In this regard, an electric vehicle that replaces the engine with an electric motor has no vibration source, so that when considering the improvement of ride comfort, the electric vehicle is advantageous compared to an internal combustion engine vehicle.

[0007] However, the absence of engine-transmitted vibrations may make drivers who pursue driving pleasure feel bored. In particular, in electric vehicles with characteristics targeting high performance, there are cases where harsh and trembling feelings must be provided, not just soft feelings. However, in conventional motor control methods, electric vehicles do not sufficiently provide this emotional factor to drivers.

[0008] At the same time, conventional electric vehicles have great difficulty in achieving virtual internal combustion engine (engine) vibration, which is the impact of backlash generated by the reducer of the drive system, etc. When the motor generates torque, the torque direction needs to be switched between driving and regeneration, and if the gear moves from one direction to the other due to the tolerance between the meshing gears, a collision occurs between the teeth of the gears. When this phenomenon occurs periodically, especially when combined with a resonance cycle, the drive system may be damaged instantly as the degree of fatigue accumulates.

[0009] Therefore, there is a need for a control technology that can virtually generate internal combustion engine (engine) vibrations as in an internal combustion engine vehicle while solving the backlash problem of the drive system.

[0010] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0011] The present disclosure relates to a method for implementing virtual internal combustion engine vibrations in an electric vehicle. Specific embodiments relate to a method that can virtually generate internal combustion engine (engine) vibrations as in an internal combustion engine vehicle while solving the drive system backlash problem in an electric vehicle.

[0012] One embodiment of the present disclosure provides a method capable of virtually generating internal combustion engine (engine) vibration in an electric vehicle as in an internal combustion engine vehicle.

[0013] Furthermore, another embodiment of the present disclosure prevents generation of backlash and impact of a drive system when a virtual internal combustion engine vibration is implemented in an electric vehicle, thereby ensuring durability of the drive system.

[0014] The embodiments of the present disclosure are not limited to the aforementioned embodiments, and other embodiments that are not mentioned can be clearly understood from the following description by those skilled in the art to which the present disclosure pertains (hereinafter, referred to as “those skilled in the art”).

[0015] An exemplary embodiment of the present disclosure provides a method for realizing virtual internal combustion engine vibration in an electric vehicle, the method comprising: collecting, by a control unit, operating variable information for determining a torque command and realizing virtual internal combustion engine vibration when the electric vehicle is traveling; determining, by the control unit, a virtual internal combustion engine vibration characteristic based on the collected operating variable information; determining, by the control unit, a vibration torque command having the determined virtual internal combustion engine vibration characteristic; correcting, by the control unit, one or both of the vibration characteristic and the value of the vibration torque command based on a basic motor torque command determined by the operating variable information and preset backlash occurrence area information; determining, by the control unit, a final motor torque command using the basic motor torque command and the corrected vibration torque command, and controlling the operation of the vehicle drive motor according to the determined final motor torque command.

[0016] Therefore, the method for implementing virtual internal combustion engine vibration in an electric vehicle according to an embodiment of the present disclosure can virtually and realistically generate internal combustion engine (engine) vibrations in an electric vehicle as in an internal combustion engine vehicle, thereby providing different operating sensitivities to the driver. In addition, when the virtual internal combustion engine vibration is implemented in an electric vehicle, the generation and impact of the backlash of the drive system can be prevented, thereby ensuring the durability of the drive system.

[0017] It should be understood that the term "vehicle" or "vehicle" or "vehicle-related" or other similar terms used herein include conventional motor vehicles, such as passenger cars including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including various boats and ships, aircraft, etc., and include hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As described herein, a hybrid vehicle is a vehicle having two or more power sources, such as a gasoline-powered vehicle and an electric-powered vehicle.

[0018] The above and other features of the present disclosure are discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other features of the present disclosure will now be described in detail with reference to certain exemplary examples shown in the accompanying drawings, which are given hereinafter by way of illustration only and thus do not limit the present disclosure, wherein:

[0020] Figure 1 is a block diagram illustrating a method for implementing virtual engine vibration using a virtual engine model according to an embodiment of the present disclosure;

[0021] Figure 2 is a block diagram showing a configuration of an apparatus for performing a process of implementing virtual engine vibration according to an exemplary embodiment of the present disclosure;

[0022] Figure 3 is a flow chart illustrating a process of implementing virtual engine vibration according to an exemplary embodiment of the present disclosure;

[0023] Figure 4 is a diagram illustrating an example of performing vibration amplitude correction according to an exemplary embodiment of the present disclosure;

[0024] Figure 5 is a diagram illustrating an example of performing vibration offset correction for preventing impact of backlash according to an exemplary embodiment of the present disclosure; and

[0025] Figure 6 is a diagram illustrating an example of superimposing and applying vibration amplitude correction and vibration offset correction according to an exemplary embodiment of the present disclosure.

[0026] It should be understood that the drawings are not necessarily to scale, and the drawings present a slightly simplified representation of various preferred features that illustrate the basic principles of the present disclosure. The specific design features of the embodiments of the present disclosure as disclosed herein (including, for example, specific dimensions, orientations, locations, and shapes) will be determined by specific intended applications and use environment segments.

[0027] In the drawings, reference numerals denote the same or equivalent parts of embodiments of the present disclosure throughout the several figures of the drawing. DETAILED DESCRIPTION

[0028] The specific structure-to-function description disclosed in the exemplary embodiments of the present disclosure is shown only for the purpose of describing the exemplary embodiments according to the concepts of the present disclosure, and the exemplary embodiments according to the concepts of the present disclosure can be implemented in various forms. In addition, it should not be interpreted that the present disclosure is limited to the exemplary embodiments described in this specification, and it should be understood that the present disclosure includes all changes, equivalents or replacements included in the spirit or technical scope of the present disclosure.

[0029] Meanwhile, the terms such as first and / or second in the present disclosure may be used to describe various components, but the components should not be limited to these terms. The terms are only used for the purpose of distinguishing one component from another component, and for example, without departing from the scope of the concept according to the present disclosure, the first component may be named as the second component, and similarly, the second component may also be named as the first component.

[0030] When a component is referred to as being "connected" or "coupled" to another component, the component may be directly connected or coupled to the other component, but it should be understood that other components may also exist between the components. On the other hand, when a component is referred to as being "directly connected" or "directly coupled" to another component, it should be understood that no other components exist between the components. Other expressions describing the relationship between components, namely "between" and "immediately between" or "adjacent" and "directly adjacent", should also be interpreted in the same manner.

[0031] Throughout the specification, the same reference numerals represent the same parts. Meanwhile, the terms used in this specification are used to describe exemplary embodiments and do not limit the present disclosure. In this specification, the singular form also includes the plural form, unless the context specifically mentions. The terms "comprise" and / or "include" used in the specification refer to the components, steps, operations and / or elements described herein without excluding the presence or addition of one or more other components, steps, operations and / or elements.

[0032] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0033] Embodiments of the present disclosure relate to a method capable of realistically generating virtual internal combustion engine (engine) vibration using a drive motor in an electric vehicle. Specific embodiments relate to a method capable of preventing generation of backlash and impact in a drive system even while achieving virtual internal combustion engine vibration.

[0034] To this end, an embodiment of the present disclosure generates a torque for simulating the vibration characteristics in an internal combustion engine vehicle by a drive motor in an electric vehicle that does not have an internal combustion engine (engine), thereby realizing virtual internal combustion engine vibration, and simultaneously adjusting the amplitude (magnitude) and value of the vibration torque command, thereby alleviating the impact of the tooth gap.

[0035] Figure 1 The principle and method of realizing the vibration of an internal combustion engine (engine) using a virtual engine model according to an embodiment of the present disclosure are shown. In the following description, the motor used to realize the vibration of the virtual internal combustion engine is a drive motor connected to a drive wheel to drive the vehicle. In addition, those skilled in the art will be able to understand that in the following description, the internal combustion engine and the engine are used as having the same meaning.

[0036] The embodiments of the present disclosure can collect the actual operation variable information in the electric vehicle for realizing the virtual internal combustion engine vibration in real time when the electric vehicle is traveling, and determine the vibration torque instruction with the virtual vibration characteristics in the internal combustion engine vehicle based on the actual operation variable information. Alternatively, the embodiments of the present disclosure can determine the virtual state variable information in the virtual internal combustion engine (engine) model based on the collected actual operation variable information, and then determine the vibration torque instruction with the vibration characteristics in the internal combustion engine vehicle to be realized by the determined virtual state variable information. Alternatively, the embodiments of the present disclosure can use both the actual operation variable information and the virtual state variable information to determine the vibration torque instruction.

[0037] Here, the operation variable information is information about the actual system possessed by the electric vehicle, and may be real-time vehicle operation information in the electric vehicle. In addition, the vehicle operation information may include driver input information and operation state information in the actual electric vehicle.

[0038] The vehicle operation information may be sensor detection information detected by a sensor and input through a vehicle network, information determined by the control unit itself according to an embodiment of the present disclosure, or information input to the control unit from another control unit within the vehicle through a vehicle network according to an embodiment of the present disclosure.

[0039] Specifically, the driver input information of the manipulated variable information may be a driver pedal input value, and the driver pedal input value may be an accelerator pedal input value (APS value) and a brake pedal input value (BPS value). Here, the accelerator pedal input value is generated by the driver's accelerator pedal operation, and as described later, may be information detected by an accelerator pedal detection unit (APS). In addition, the brake pedal input value is generated by the driver's brake pedal operation, and as described later, may be information detected by a brake pedal detection unit (BPS).

[0040] The operation state information of the operation variable information may include the motor torque and the drive system speed. Here, the motor torque may be a motor torque command determined by the control unit based on the vehicle operation information collected by the vehicle. More specifically, as described later, the motor torque may be a motor torque command generated by the basic torque command generation unit ( Figure 2 The basic motor torque command is determined and generated by the reference numeral “21” in the figure.

[0041] The basic motor torque command can be determined by the operating variable information, and a detailed description of the method and process of determining and generating the basic motor torque command for controlling the torque output of the drive motor in the electric vehicle will be omitted because they are technical contents known in the art.

[0042] The drive system speed may include the motor speed, and the motor speed is the actual motor speed measured by the speed detection unit. Here, as described later, the speed detection unit may be a rotary transformer mounted on the drive motor. In addition, the drive system speed may include the wheel speed of the drive wheel, and in this case, the speed detection unit may be a wheel speed sensor mounted on the drive wheel. In addition, the drive system speed may also include the drive shaft speed. As described above, the drive system speed according to an embodiment of the present disclosure may be defined as the speed at any position of the vehicle drive system including the motor, the reducer, the drive shaft, and the drive wheel.

[0043] In addition, according to an exemplary embodiment of the present disclosure, the vibration torque command can be determined by a function of the actual operating variable, the vibration torque command can be determined by a function of a virtual state variable in the internal combustion engine, and the virtual state variable is determined by the value of the actual operating variable, or the vibration torque command can also be determined by a function of the actual operating variable and the virtual state variable.

[0044] According to an exemplary embodiment of the present disclosure, a preset virtual internal combustion engine model may be used to acquire values ​​of virtual state variables in the internal combustion engine from values ​​of actual operating variables in the electric vehicle.

[0045] According to an exemplary embodiment of the present disclosure, if a virtual internal combustion engine model including a virtual engine and a virtual transmission is to be used, the virtual engine speed becomes the input speed of the virtual transmission. The virtual engine speed can be calculated by a variable multiple value of the actual drive system speed detected by the speed detection unit, wherein the drive system speed can be the motor speed. At this time, in order to calculate the virtual engine speed, the value of the coefficient multiplied by the motor speed can be a value determined by the virtual transmission, the transmission ratio model, and the virtual current gear.

[0046] A control method for generating a virtual shift feel of an electric vehicle is known to generate and realize a multi-stage shift feel by torque control of a drive motor in an electric vehicle without a multi-stage transmission. In addition, it is known that a virtual engine speed is used as one of virtual state variables necessary for generating and realizing a multi-stage shift feel in a control process for generating a virtual shift feel in an electric vehicle.

[0047] As described above, the virtual engine speed, as one of the virtual state variables for generating and realizing the multi-stage shift feeling, can be used as a virtual state variable for realizing the virtual internal combustion engine vibration according to an exemplary embodiment of the present disclosure. According to an exemplary embodiment of the present disclosure, the virtual vibration control unit can determine the virtual engine speed using the virtual vehicle speed and the gear ratio information of the virtual current gear.

[0048] Here, the virtual vehicle speed may be calculated as a value directly proportional to the actual motor speed using the actual motor speed as one of the actual operating variables and the virtual final reduction gear ratio, wherein the virtual final reduction gear ratio is a preset value in the virtual vibration control unit. According to an exemplary embodiment of the present disclosure, the virtual vehicle speed may be calculated using the actual motor speed and the virtual final reduction gear ratio measured while the vehicle is traveling, and the virtual engine speed may be calculated in real time from the virtual vehicle speed.

[0049] At this time, the virtual engine speed can be obtained by multiplying the virtual vehicle speed by the virtual transmission ratio of the virtual current gear, or the virtual engine speed can also be obtained by multiplying the drive system speed (such as the motor speed) by the virtual transmission ratio of the virtual current gear.

[0050] In addition, the virtual current gear can be determined from the virtual vehicle speed and the accelerator pedal input value (APS value) according to a preset shift plan map in the virtual vibration control unit. As described above, when the virtual current gear is determined, the virtual engine speed can be calculated in real time using the virtual transmission ratio, virtual vehicle speed or motor speed corresponding to the gear.

[0051] As described above, the virtual state variable determined using the manipulated variable as an input in the virtual internal combustion engine (engine) model is used to determine the vibration torque command alone or together with the manipulated variable, and when generating the vibration torque command, after the virtual vibration characteristic is determined, the final vibration torque command for alleviating the backlash is determined by processing such as vibration amplitude correction and vibration offset correction to be described later. Here, the virtual vibration characteristic may include vibration frequency and vibration amplitude (amplitude).

[0052] Next, after adding the vibration torque command determined as described above to the original motor torque command, the torque is generated by the motor by controlling the operation of the motor according to the final motor torque command added. Therefore, as a result, a virtual vibration such as an actual internal combustion engine vibration can be generated. At this time, the amplitude and value of the vibration torque component are corrected at the timing point where the impact of the tooth gap is expected to occur, so that the impact of the tooth gap does not occur. That is, as described later, a vibration amplitude correction for correcting the amplitude of the vibration torque component and a vibration offset correction for offsetting and correcting the value of the vibration torque component can be performed.

[0053] According to an exemplary embodiment of the present disclosure, the vibration torque instruction becomes a correction torque instruction for preventing backlash and realizing virtual internal combustion engine vibration. In addition, the original motor torque instruction is an instruction corresponding to the driver's requested torque determined according to the driver's operation input value, that is, a basic motor torque instruction, and becomes the motor torque instruction before correction. In addition, according to an embodiment of the present disclosure, the correction of the original motor torque instruction may mean the sum of the original motor torque instruction and the vibration torque instruction. At this time, the final motor torque instruction after summation becomes the corrected motor torque instruction.

[0054] Hereinafter, a method for implementing virtual vibration according to an exemplary embodiment of the present disclosure will be described in more detail with reference to the following drawings.

[0055] Figure 2 is a block diagram showing a configuration of an apparatus for performing a process of realizing virtual internal combustion engine (engine) vibration according to an exemplary embodiment of the present disclosure, and Figure 3 is a flowchart illustrating a process of implementing virtual internal combustion engine (engine) vibration according to an exemplary embodiment of the present disclosure.

[0056] like Figure 2 As shown, the device for performing processing for realizing virtual internal combustion engine vibration according to an exemplary embodiment of the present disclosure is configured to include: an operation information detection unit 12, the operation information detection unit 12 is configured to detect vehicle operation information (operation variable information); a first control unit 20, configured to generate and output a torque instruction based on the vehicle operation information detected by the operation information detection unit 12; and a second control unit 30, configured to control the operation of the drive device 41 according to the torque instruction output by the first control unit 20.

[0057] In addition, the apparatus for executing the process of implementing virtual internal combustion engine vibration according to an embodiment of the present disclosure may further include an interface unit 11 configured to allow the driver to selectively input one of on and off of the virtual internal combustion engine vibration implementation function.

[0058] Although the following description is made by classifying the control objects into the first control unit 20 and the second control unit 30, the control processing and driving control processing for realizing the virtual internal combustion engine vibration of the vehicle according to the embodiment of the present disclosure can also be performed by one integrated control element instead of multiple control units.

[0059] A plurality of control units and an integrated control element may be selectively referred to as a control unit, and the control process for realizing the virtual internal combustion engine vibration according to the embodiment of the present disclosure described below may be performed by the control unit. For example, in the configuration of the exemplary embodiment to be described later, the control unit may be collectively referred to as both the first control unit 20 and the second control unit 30.

[0060] The interface unit 11 is usable as long as it is a device through which the driver can operate the on / off of the virtual internal combustion engine vibration implementation function in the vehicle. As an example, in addition to an operating device such as a button or switch provided in the vehicle, the interface unit 11 may also be an input device of an audio-visual navigation (ANV) system, a touch screen, etc.

[0061] The interface unit 11 may be connected to the first control unit 20, and more specifically, the first control unit 20 may also be respectively connected to the virtual vibration control unit 22 to be described later. Therefore, when the driver performs the on and off operation through the interface unit 11, the on signal or the off signal may be input from the interface unit 11 to the virtual vibration control unit 22 of the first control unit 20. As a result, the virtual vibration control unit 22 of the first control unit 20 may recognize the on or off operation state of the virtual internal combustion engine vibration realization function by the driver (see Figure 3 Step S1 in ).

[0062] According to an embodiment of the present disclosure, the virtual internal combustion engine vibration implementation function is executed only when the driver inputs the start function through the interface unit 11 while the vehicle is traveling. In addition, when the interface unit 11 is a vehicle input device provided in the vehicle, as another example of the interface unit 11, the driver can also perform the start and stop operation of the virtual internal combustion engine vibration implementation function through a mobile device. The mobile device needs to be communicatively connected to the vehicle-mounted device, for example, the first control unit 20, and for this purpose, an input / output communication interface for communication connection between the mobile device and the first control unit 20 is used.

[0063] The operation information detection unit 12 is a configuration unit configured to detect vehicle operation information (operation variable information) necessary for executing the virtual internal combustion engine vibration realization function and vehicle operation information (operation variable information) necessary for generating a basic motor torque command in the vehicle. According to an exemplary embodiment of the present disclosure, the operation information detection unit 12 may include: an accelerator pedal detection unit configured to detect accelerator pedal input information (accelerator pedal input value) according to the driver's accelerator pedal operation; a brake pedal detection unit configured to detect brake pedal input information (brake pedal input value) according to the driver's brake pedal operation; and a speed detection unit configured to detect the speed of the vehicle drive system.

[0064] Here, the accelerator pedal detection unit may be a general accelerator position sensor (APS) mounted on the accelerator pedal to output an electrical signal according to the driver's accelerator pedal operation state. The brake pedal detection unit may be a general brake pedal sensor (BPS) mounted on the brake pedal to output an electrical signal according to the driver's brake pedal operation state.

[0065] The speed detection unit acquires the speed information of the vehicle drive system, wherein the speed information of the vehicle drive system may include the motor speed, that is, the rotation speed of the drive motor 41. At this time, the speed detection unit may be a rotary transformer mounted on the drive motor 41. Alternatively, the speed information of the vehicle drive system may include the rotation speed of the drive wheel 43 (drive wheel speed), and at this time, the speed detection unit may be a wheel speed sensor mounted on the drive wheel 43. Alternatively, the rotation speed information of the vehicle drive system may include the rotation speed of the drive shaft (drive shaft speed), and at this time, the speed detection unit may be a sensor capable of detecting the rotation speed of the drive shaft.

[0066] In addition, the first control unit 20 includes: a basic torque instruction generating unit 21, which is configured to determine and generate a basic motor torque instruction from vehicle operation information; a virtual vibration control unit 22, which is configured to determine and generate a correction torque instruction (i.e., a vibration torque instruction), which is used to generate and realize the motor vibration for realizing the virtual internal combustion engine vibration using one or both of the actual operation variables and the virtual state variables; and a final torque instruction generating unit 23, which is configured to generate a corrected final motor torque instruction by correcting the basic motor torque instruction using the correction torque instruction.

[0067] The basic motor torque command is a motor torque command determined and generated based on vehicle operation information collected during normal electric vehicle driving, and the basic torque command generating unit 21 can be a vehicle control unit (VCU) configured to generate a motor torque command based on vehicle operation information in a normal electric vehicle or a part thereof.

[0068] In addition, the virtual vibration control unit 22 is a new configuration unit configured to determine, generate and output a vibration torque instruction, which is a correction torque instruction used only to implement virtual internal combustion engine vibration separately from the basic motor torque instruction according to an embodiment of the present disclosure, and the virtual vibration control unit 22 can be added as a part of the vehicle control unit within the vehicle control unit, or be set as a control element separate from the vehicle control unit.

[0069] According to an exemplary embodiment of the present disclosure, the virtual vibration control unit 22 is a control element configured to perform overall control for realizing virtual internal combustion engine vibration, and acquires virtual state variable information (virtual internal combustion engine model) in the internal combustion engine while acquiring actual operation variables (drive system speed, etc.) in the electric vehicle based on actual operation variables (see Figure 3 Step S2 in ).

[0070] In addition, the virtual vibration control unit 22 determines the virtual vibration characteristic using one or both of the actual operation variable and the virtual state variable (see Figure 3 Step S3 in the above method) and determine and generate a final correction torque instruction (vibration torque instruction) for realizing virtual internal combustion engine vibration and alleviating tooth backlash from the determined virtual vibration characteristic information (see Figure 3 Step S4 in ).

[0071] The basic motor torque command input from the basic torque command generating unit 21 is corrected by the correction torque command input through the virtual vibration control unit 22, and the final torque command generating unit 23 can calculate the final motor torque command by summing the basic motor torque command and the vibration torque command as the correction torque command.

[0072] The second control unit 30 is a control unit configured to receive the torque command sent by the first control unit 20 (i.e., the final motor torque command determined by the final torque command generating unit 23 of the first control unit 20) to control the operation of the drive device 41. Here, the drive device 41 is a drive motor 41 connected to a drive wheel 43 to drive the vehicle. At this time, the second control unit 30 may be a well-known motor control unit (MCU) configured to drive the drive motor 41 through an inverter in a general electric vehicle and control the driving of the drive motor 41.

[0073] According to an exemplary embodiment of the present disclosure, a vibration torque instruction for realizing virtual internal combustion engine vibration imparts virtual internal combustion engine vibration to the torque of the motor as the drive device 41, and generates a very small tremor of the motor torque matching the virtual vibration characteristic. The vibration torque instruction may have an instruction value that fluctuates in a waveform with a predetermined frequency (or period) and amplitude (vibration amplitude). That is, the vibration torque instruction may have an instruction value interlocked with the virtual vibration characteristic, and, for example, has an instruction value corresponding to the vibration frequency (or period) and amplitude (vibration amplitude) among the virtual vibration characteristics.

[0074] According to an exemplary embodiment of the present disclosure, Figure 2As shown, the torque and rotational force output by the electric motor serving as the driving device 41 are reduced by the reducer 42 and then transmitted to the driving wheel 43, and when the drive of the electric motor 41 is controlled according to the final motor torque command corrected by the vibration torque command, the motor torque to which the virtual internal combustion engine vibration is added is output.

[0075] Figure 3 It is shown that when the vibration torque command is corrected in step S4 and the final motor torque command is determined by correcting the basic motor torque command according to the corrected vibration torque command, whether the motor state is a normal operating state is confirmed in step S5, the gear tightening state is confirmed in step S6, and then the drive of the motor 41 is controlled according to the final motor torque command in step S7, thereby generating a vibration effect.

[0076] At the same time, as described above, the virtual vibration control unit 22 of the first control unit 20 can use the actual operating variables and the virtual state variables to determine the virtual vibration characteristics, and can determine the virtual vibration characteristics based on the motor torque and the motor speed, and for example, can determine the vibration torque command for realizing the virtual internal combustion engine vibration from the determined virtual vibration characteristics. In addition, the virtual vibration control unit 22 can correct the vibration torque command determined by the virtual vibration characteristics based on the vehicle operation information so as to determine the final vibration torque command. According to an exemplary embodiment of the present disclosure, the correction of the vibration torque command can be a vibration amplitude correction, a vibration offset correction, or a simultaneous correction of the vibration amplitude and the vibration offset. Here, the vibration amplitude refers to the amplitude of the vibration torque component, and the vibration offset correction refers to offsetting and correcting the value of the vibration torque component.

[0077] Figure 4 1 is a diagram for explaining vibration amplitude correction according to an exemplary embodiment of the present disclosure, and a diagram showing an example of correcting a vibration torque command based on a motor torque and a motor speed. According to an exemplary embodiment of the present disclosure, the motor torque used to determine the virtual vibration characteristic may be a motor torque command, and the motor torque command may be a basic motor torque command determined in real time by the basic torque command generation unit 21.

[0078] The impact due to the gear backlash may occur at a timing point when the direction of the motor torque is switched in the drive system including the speed reducer 42, and at this time, as shown in FIG. Figure 4As shown, the tooth gap occurrence area can be a motor torque area having zero torque and a determined torque range approximately close to zero torque. According to an exemplary embodiment of the present disclosure, the tooth gap occurrence area is information preset and used in the control unit, and can be set to a torque range having a determined negative (-) torque value as a minimum value and a determined positive (+) torque value as a maximum value. In addition, according to an embodiment of the present disclosure, switching of the motor torque direction means that the motor torque switches from a positive (+) value to a negative (-) value, or conversely, the motor torque switches from a negative value to a positive value. In addition, a motor torque having a positive value represents a driving torque, and a motor torque having a negative value represents a regenerative torque.

[0079] In addition, the impact caused by the gear backlash may occur at the timing point of the motor torque direction switching, and when the vibration torque command is applied to realize the virtual internal combustion engine vibration without considering this problem, it may cause a significant impact, thereby reducing the operability of the vehicle. Therefore, in order to prevent such a phenomenon, a method for preventing the final motor torque command from frequently switching directions due to the virtual internal combustion engine vibration realization function is required. To this end, when the basic motor torque command exists in the backlash occurrence area, a method of adjusting the vibration amplitude (amplitude) of the vibration characteristic value of the vibration torque command is applicable.

[0080] According to an exemplary embodiment of the present disclosure, the vibration amplitude (amplitude) of the vibration torque instruction before correction determined by the virtual vibration characteristic can be obtained by the drive system speed (which can be the motor speed, the wheel speed, the drive shaft speed, etc.), the virtual engine speed, or the basic motor torque instruction. At this time, as the speed value such as the drive system speed and the virtual engine speed increases, the vibration amplitude (amplitude) of the vibration torque instruction before correction can be determined to be a smaller value. In addition, when the basic motor torque instruction decreases, the vibration amplitude (amplitude) of the vibration torque instruction before correction can be determined to be a smaller value. Here, the basic motor torque instruction can be replaced by the accelerator pedal input value (APS value) detected by the accelerator pedal detection unit, and as the accelerator pedal input value decreases, the vibration amplitude (amplitude) of the vibration torque instruction before correction can be determined to be a smaller value.

[0081] Alternatively, the vibration amplitude of the torque command before correction may be finally determined as a value obtained by multiplying the vibration amplitude determined as a smaller value when the speed value (such as the drive system speed and the virtual engine speed) increases by the vibration amplitude determined as a larger value when the basic motor torque command and the accelerator pedal input value increase. Alternatively, the vibration amplitude of the vibration torque command before correction may also be determined as a preset value ( Figure 4 “High” value in the left graph in the figure).

[0082] In addition, according to an exemplary embodiment of the present disclosure, the vibration frequency (or period) of the vibration torque instruction before correction can be obtained by the drive system speed or the virtual engine speed. At this time, as the drive system speed or the virtual engine speed increases, the vibration frequency can be determined to be a larger value.

[0083] In addition, according to an exemplary embodiment of the present disclosure, since the basic motor torque command value is close to the backlash occurrence area, the corrected vibration amplitude for preventing backlash can be determined to be a smaller value. That is, when the difference with the minimum value or the maximum value of the backlash occurrence area decreases, the basic motor torque command value is corrected so that the vibration amplitude of the vibration torque command becomes a smaller value. In addition, if the basic motor torque command exists in the backlash occurrence area, the vibration amplitude of the vibration torque command can be corrected to a zero value.

[0084] Figure 4 The left figure in FIG. 1 shows the state before the amplitude of the vibration torque command is corrected, and Figure 4 The right figure shows the state after the amplitude of the vibration torque command is corrected (ie, adjusted).

[0085] like Figure 4 As shown in the right figure in , when the vibration amplitude before correction is determined (for example, Figure 4 ), if the basic motor torque command exists in the determined backlash occurrence region, the vibration amplitude is reduced to the set torque value (for example, Figure 4 Here, the set torque value may be a value of zero. As a result, when the basic motor torque command exists in the backlash occurrence region, the vibration torque command corrected based on the reduced vibration amplitude may be determined to be a value of zero.

[0086] In addition, when the value of the basic motor torque command approaches the tooth gap occurrence area (i.e., when the difference with the minimum value or the maximum value of the tooth gap occurrence area decreases), the vibration amplitude of the vibration torque command can gradually decrease, and then when the basic motor torque command moves away from the tooth gap occurrence area, the vibration amplitude of the vibration torque command can gradually increase.

[0087] As a result, when the vibration torque command is determined as described above, the basic motor torque command can be corrected by using the vibration torque command with the corrected vibration amplitude (amplitude) to determine the final motor torque command. As described above, it is observed whether the value of the basic motor torque command exists in the backlash occurrence area, and the vibration amplitude is reduced in real time based on the observation result so that the final motor torque command does not vibrate in the backlash occurrence area and the impact of the backlash does not occur.

[0088] As described above, the method for correcting the vibration amplitude to prevent the impact of backlash will be described using a specific example. First, the vibration amplitude (amplitude) of the vibration torque command is determined to be the minimum difference between the current value of the basic motor torque command and the value in the backlash occurrence area or less. That is, when the final motor torque command is determined by T cmd The basic motor torque command (which does not consider the vibration torque) is represented by T base Indicated by T vib When T cmd By adding T base and T vib The area closest to the tooth gap is obtained by adding base The current value of the torque value is given by T bls * indicates that |T base -T bls *| or smaller value can be determined as T vib At this time, if T vib If the amplitude is not well defined, the value inferred from the peak of the past signal can be determined as T vib The amplitude.

[0089] As mentioned above, the closest to T base The torque value T of the backlash occurrence area of ​​the current value bls * can be one of the two boundary values ​​(lower limit value and upper limit value) of the tooth backlash occurrence area, and T bls * Indicates that base The difference between the current values ​​of is the torque value of the minimum backlash occurrence area. That is, when the basic motor torque command value is a positive value (drive torque command value) greater than the backlash occurrence area, T bls * The value becomes the maximum value (upper limit) of the torque value in the backlash occurrence area (T bls，高 ). On the contrary, when the basic motor torque command value is a negative value (regenerative torque command value) smaller than the backlash occurrence region, T bls * The value becomes the minimum value (lower limit value) of the torque value in the backlash occurrence area (T bls，低 ).

[0090] The above content will be explained below using specific numerical values ​​as an example.

[0091] Example (1): The backlash occurrence area set in the control unit is T bls，低 = -5 Newton meters (Nm) and T bls，高 =15Nm (-5 to 15) in the torque range, when T baseis 40Nm and T vib When it is 20×sin(ωt), the T closest to 40Nm base The value of the tooth gap occurrence area (positive boundary value) is T bls * =T bls，高 =15Nm, so the result is |T base -T bls *|=25Nm. Therefore, due to T vib =20×sin(ωt),T vib The amplitude does not exceed 25, so the current T vib =20×sin(ωt).

[0092] Example (2): In the area where backlash occurs, T bls，低 =-5Nm and T bls，高 =15Nm (-5 to 15) in the torque range, when T base is 25Nm and T vib When it is 40×sin(ωt), the T closest to 25Nm base The value of the tooth gap occurrence area (positive boundary value) is T bls * =T bls，高 =15Nm, so the result is |T base -T bls * |=10Nm. Therefore, due to T vib =40×sin(ωt) The amplitude 40 exceeds 10, so the current T cannot be maintained. vib =40×sin(ωt). At this time, T vib The amplitude is adjusted to 10Nm or less.

[0093] at the same time, Figure 5 is a diagram illustrating an example of performing vibration offset correction for preventing impact of backlash according to an exemplary embodiment of the present disclosure. Figure 5 The left diagram in shows an example of a state before the vibration offset correction is performed, and the right diagram shows an example in which the vibration offset correction is performed. Figure 5 The vibration torque commands generated before and after correction and the final motor torque command value are compared before and after correction when the motor torque (basic motor torque command), the motor speed as the drive system speed, and the backlash occurrence region are all the same.

[0094] When the vibration amplitude correction method is a method capable of preventing the torque direction (torque vibration) from switching in the backlash occurrence region, Figure 5The vibration offset correction method shown is a method of completely preventing the torque command from entering the backlash occurrence region. However, this method has the advantage of reliably preventing the impact of backlash, but has the limitation that it may not accurately follow the basic motor torque.

[0095] Therefore, it can be applied Figure 5 The vibration offset correction shown is used to achieve virtual internal combustion engine vibration in a stopped state. This is because when a virtual idle vibration is achieved in a state where the brake pedal is applied, etc., it is meaningless to follow the accuracy of the basic motor torque. However, since the motor does not need to use the offset torque for unexpected acceleration, the vibration offset correction can be applied in a state where the drive system is tightened (i.e., the drive gear is tightened, not the neutral state, etc.).

[0096] Specifically describing the vibration offset correction method, an offset value is given to the vibration torque command to prevent a final motor torque command obtained by summing the basic motor torque command and the vibration torque command from entering a backlash occurrence region.

[0097] In other words, when the basic motor torque command T base (torque command without considering vibration torque) and vibration torque command T vib The final motor torque command T is obtained by summing cmd If the current basic motor torque command T base In the direction to be offset, the boundary value (minimum or maximum value) of the area where backlash occurs is T bls * And T vib The amplitude is A, then "T bls * -T base + (sign (offset)) × A" or a larger value (depending on the offset direction, it can also be "T bls * -T base +(sign (offset))×A″ or a smaller value) is determined as the vibration torque command T vib The offset amplitude.

[0098] However, when the offset direction to be given and the calculated offset direction are opposite to each other, this means that even in the current state, the final motor torque command T after summation cmd It has also left the tooth gap generation area, so there is no need to give an offset. In addition, if the vibration torque command T vib If the amplitude A is not clearly defined, the amplitude A can be used by inferring from past signal peaks, etc.

[0099] As described above, the direction in which the offset is given means one of the driving torque direction and the regenerative torque direction, and if the offset direction is the driving torque direction, it means that the vibration torque command is offset to a positive value greater than the backlash occurrence region. On the contrary, if the offset direction is the regenerative torque direction, it means that the vibration torque command is offset to a negative value less than the backlash occurrence region. In addition, if the offset direction is the driving torque direction, the "sign (offset)" becomes +1; and if the offset direction is the regenerative torque direction, the "sign (offset)" becomes -1.

[0100] The above contents will be described below using specific numerical values ​​as an example.

[0101] Example (1): In the area where backlash occurs, T bls，低 =-5Nm and T bls，高 =15Nm (-5 to 15) in the torque range, when T base is -1Nm and T vib When the value is 20×sin(ωt), and an attempt is made to give an offset in the regenerative torque direction, the result is T bls * =T bls，低 = -5Nm, so that T bls * -T base +(-1)×A=-5-(-1)-20=-24 Nm or any value of less is determined as the offset value of the vibration torque.

[0102] Example (2): In the area where backlash occurs, T bls，低 =-5Nm and T bls，高 =15Nm (-5 to 15) in the torque range, when T base is 20Nm and T vib When the value is 7×sin(ωt), and an attempt is made to give an offset in the driving torque direction, the result is T bls * =T bls，高 =15Nm, so that T bls * -T base Any value of +1×A=15-20+7=2 Nm or more is determined as the offset value of the vibration torque.

[0103] As mentioned above, if the offset direction is the driving torque direction, then “T bls * -T base +(sign(offset))×A” or any value of a larger value is determined as the magnitude of the offset, and if the offset direction is the regenerative torque direction, “T bls * -Tbase Any value of +(sign(offset))×A” or less is determined as the magnitude of the offset.

[0104] Reference Figure 5 In the left figure, when the vibration offset correction is not performed, the vibration offset value is 0, so that the value of the vibration torque command is not offset, and in this case, the final motor torque command is located within the tooth gap occurrence area to cause the impact of the tooth gap.

[0105] Reference Figure 5 In the right figure of FIG, when the vibration offset correction is performed in the stopped state, the vibration offset value is determined, and then the vibration torque command is offset by the vibration offset value in the driving torque direction. As a result, the final motor torque command obtained by adding the vibration torque command after the offset correction to the basic motor torque command becomes a state outside the tooth gap occurrence area, thereby preventing the occurrence of tooth gap impact.

[0106] Next, a method of simultaneously superimposing and applying vibration magnitude (amplitude) correction and vibration offset correction may be applied to prevent impact of backlash. Figure 6 is a diagram illustrating an example of superimposing and applying vibration amplitude correction and vibration offset correction according to an exemplary embodiment of the present disclosure. Figure 6 Shown from left to right are a case where no correction is performed, a case where vibration amplitude correction is performed, a case where vibration offset correction is performed, and a case where vibration amplitude correction and vibration offset correction are performed simultaneously.

[0107] When the switching of the torque direction in the backlash occurrence region is prevented only by vibration magnitude (amplitude) correction, the impact of the backlash can be eliminated, but it is difficult to realize virtual vibration.

[0108] In contrast, when the torque command is prevented from entering the backlash occurrence region only by vibration offset correction, the impact of the backlash can be eliminated, but it is difficult to follow the original basic motor torque command.

[0109] Therefore, virtual vibration can be achieved by superimposing and applying two methods to apply a partially corrected vibration amplitude (amplitude), and the switching of the torque direction in the tooth gap occurrence area that may occur at this time is prevented by vibration offset correction. When superimposed correction is performed, the vibration amplitude (amplitude) is lower than originally expected but virtual vibration can be achieved, and the following ability of the basic motor torque command can be further enhanced instead of preventing the impact of the tooth gap only by offset correction.

[0110] When the vibration amplitude correction and the vibration offset correction are superimposed and applied, the correction width of the vibration amplitude is limited so that the entire impact of the backlash cannot be eliminated by the vibration amplitude correction alone. In addition, the vibration offset correction is performed using the vibration amplitude information to which the limited correction is applied as an input of the offset correction. In this way, the vibration amplitude correction and the vibration offset correction can be complementarily operated, thereby preventing and minimizing the impact of the backlash.

[0111] As described above, although exemplary embodiments of the present disclosure have been described in detail, the scope of the present disclosure is not limited thereto, and various changes and modifications by those skilled in the art using the basic concept of the present disclosure defined by the appended claims are also included in the scope of the present disclosure.

Claims

1. A method for implementing virtual internal combustion engine vibration in an electric vehicle, the method comprising: When the electric vehicle is running, operating variable information for determining a torque command and realizing the virtual internal combustion engine vibration is collected; determining a virtual internal combustion engine vibration characteristic based on the collected operating variable information; determining a vibration torque command having the determined virtual internal combustion engine vibration characteristic; Based on a basic motor torque command determined by the collected manipulated variable information and a preset backlash occurrence region, the vibration torque command is corrected by correcting the determined virtual internal combustion engine vibration characteristic of the vibration torque command and / or the value of the vibration torque command; determining a final motor torque command using the basic motor torque command and the corrected vibration torque command; and Operation of a drive motor of the electric vehicle is controlled according to the determined final motor torque command.

2. The method according to claim 1, wherein: The virtual internal combustion engine vibration characteristics include vibration frequency and vibration amplitude.

3. The method according to claim 1, wherein: The manipulated variable information collected for determining the virtual internal combustion engine vibration characteristic includes at least one of a drive system speed, an accelerator pedal input value, the basic motor torque command, and a virtual engine speed determined by the drive system speed.

4. The method according to claim 3, wherein: The virtual engine speed is determined as a multiple of the drive system speed.

5. The method according to claim 3, wherein: The drive system speed is the motor speed, the wheel speed of the drive wheels, or the drive shaft speed.

6. The method according to claim 3, further comprising: The backlash occurrence region is set to a torque range having a predetermined negative torque value as a minimum value and a predetermined positive torque value as a maximum value.

7. The method according to claim 6, wherein: Determining the virtual internal combustion engine vibration characteristic includes determining the value of the basic motor torque command so that the vibration amplitude of the virtual internal combustion engine vibration characteristic becomes a smaller value as the difference from the minimum value or the maximum value of the backlash occurrence region decreases.

8. The method according to claim 1, further comprising: The backlash occurrence region is set to a torque range having a predetermined negative torque value as a minimum value and a predetermined positive torque value as a maximum value.

9. The method according to claim 1, wherein: Correcting the vibration torque command by correcting the determined virtual internal combustion engine vibration characteristic of the vibration torque command includes correcting a vibration amplitude of the vibration torque command.

10. The method according to claim 9, further comprising: When the basic motor torque command is a value within the backlash occurrence region, the vibration amplitude of the vibration torque command is corrected to a zero value.

11. The method according to claim 9, further comprising: The value of the basic motor torque command is corrected so that the vibration amplitude of the vibration torque command becomes a smaller value as the difference from the minimum value or the maximum value of the backlash occurrence region decreases.

12. The method according to claim 9, further comprising: When the basic motor torque command is given by T base The minimum or maximum value of the tooth gap occurrence area is represented by T bls * When the vibration amplitude of the vibration torque command is corrected to |T base –T bls * | or any smaller value.

13. The method according to claim 1, wherein: Determining the final motor torque command includes adding the base motor torque command and the corrected vibration torque command.

14. A method for implementing virtual internal combustion engine vibration in an electric vehicle, the method comprising: When the electric vehicle is running, operating variable information for determining a torque command and realizing the virtual internal combustion engine vibration is collected; determining a virtual internal combustion engine vibration characteristic based on the collected operating variable information; determining a vibration torque command having the determined virtual internal combustion engine vibration characteristic; correcting the vibration torque command by correcting the value of the vibration torque command based on a basic motor torque command determined by the collected manipulated variable information and a preset backlash occurrence region; determining a final motor torque command using the basic motor torque command and the corrected vibration torque command; and controlling the operation of the drive motor of the electric vehicle according to the determined final motor torque command, Wherein, correcting the value of the vibration torque command includes: performing an offset correction on the value of the vibration torque command to prevent the determined final motor torque command from entering the backlash occurrence region.

15. The method according to claim 14, further comprising: The offset direction is determined to be a driving torque direction in which the vibration torque command is offset to a positive value greater than the backlash occurrence region or a regeneration torque direction in which the vibration torque command is offset to a negative value less than the backlash occurrence region.

16. The method of claim 15, wherein: When the basic motor torque command is given by T base The vibration amplitude of the vibration torque command is represented by A, and the maximum value or minimum value of the backlash occurrence area is represented by T bls * When indicating, according to the offset direction, "T bls * -T base +(sign(offset))×A" or greater or "T bls * -T base +(sign(offset))×A″ or any value of a smaller value is determined as an offset amplitude of the value for offset correction of the vibration torque command; and If the offset direction is the driving torque direction, “Sign (Offset)” is a value of “+1”, and if the offset direction is the regeneration torque direction, “Sign (Offset)” is a value of “−1”.

17. The method of claim 16, wherein: If "T bls * -T base +(sign(offset))×A” or any value of a larger value is determined as the offset amplitude, then the offset direction is the driving torque direction; and If "T bls * -T base +(sign(offset))×A″ or any value of a smaller value is determined as the offset amplitude, and the offset direction is the regenerative torque direction.

18. The method according to claim 14, wherein: Determining the final motor torque command includes adding the base motor torque command and the corrected vibration torque command.

19. The method according to claim 14, wherein: Correcting the vibration torque command includes correcting the determined virtual internal combustion engine vibration characteristic of the vibration torque command.

20. The method according to claim 19, wherein: The virtual internal combustion engine vibration characteristics include vibration frequency and vibration amplitude.

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