WO2024057465A1

WO2024057465A1 - Electric vehicle control method and electric vehicle control device

Info

Publication number: WO2024057465A1
Application number: PCT/JP2022/034487
Authority: WO
Inventors: 匡史岩本
Original assignee: 日産自動車株式会社
Priority date: 2022-09-14
Filing date: 2022-09-14
Publication date: 2024-03-21

Abstract

An aspect of the present invention pertains to an electric vehicle control method for performing attitude control that controls the attitude in the front‐back direction, by adjusting driving force distribution between a front wheel and a rear wheel which are driving wheels. In this control method, the total driving force, which is a required driving force for an electric vehicle, is calculated on the basis of operation of an accelerator pedal. In addition, on the basis of this total driving force, estimated acceleration which is an estimated value for acceleration generated when an electric vehicle is driven with the total driving force, or estimated jerk which is an estimated value for jerk that is the time change rate of acceleration, is calculated. On the basis of the estimated acceleration or the estimated jerk, attitude control execution determination for switching the attitude control on or off is performed.

Description

Electric vehicle control method and electric vehicle control device

The present invention relates to an electric vehicle control method and an electric vehicle control device.

JP4876534B2 discloses a technique for reducing the pitch rate of a vehicle when the vehicle passes over a bump in the road surface, etc., regarding an in-wheel motor type vehicle in which the effect of the suspension is not sufficiently obtained. More specifically, different braking and driving forces are applied to the front and rear wheels, and if a change in pitch rate is detected, different braking and driving forces are applied to the left and right wheels at a predetermined period. It is disclosed that it will be granted.

Conventionally, electric vehicles are known that perform posture control by adjusting the distribution of driving force to a plurality of drive wheels. In such electric vehicles, the attitude is generally controlled by adjusting driving force distribution through feedback control that feeds back detected values such as pitch rate. That is, in conventional electric vehicles, attitude control works to follow and, for example, cancel out attitude fluctuations that have already occurred, so attitude control may not be substantially in time.

Furthermore, when the driving force distribution is adjustable, the driving force distribution is usually determined in consideration of running stability so as to optimize electricity consumption. Therefore, when attitude control using driving force distribution is executed, the driving force distribution is changed from the driving force distribution that provides the best electric power consumption to the driving force distribution for controlling the attitude, and thus the electric power consumption deteriorates. For this reason, it is desirable to keep the attitude control by adjusting the driving force distribution off (non-execution state) as much as possible, and turn it on (execution state) only when necessary, even if it is a trade-off with electricity consumption.

However, as described above, when turning on/off attitude control by adjusting driving force distribution as necessary, if the start of attitude control is determined using detected values such as pitch rate, changes in attitude that have already occurred Since the determination to start attitude control is made based on this, there is a delay in the determination to start attitude control itself. As a result, the delay in attitude control is exacerbated, and the number of cases in which attitude control is not substantially completed in time increases. This is noticeable when posture control is performed by feedback control, but the same is true when posture control is performed by feedforward control. In other words, when attitude control is turned on and off as necessary, even if attitude control is performed by feedforward control, when the start judgment is made using a detected value such as pitch rate, the attitude control is delayed due to a delay in the start judgment. may not actually be completed in time.

Therefore, the present invention provides an electric vehicle that can reduce the delay in determining the start of attitude control and timely implement attitude control when attitude control by adjusting driving force distribution is turned on/off as necessary. The present invention aims to provide a control method for an electric vehicle and a control device for an electric vehicle.

An aspect of the present invention is a control method for an electric vehicle that executes attitude control that controls the attitude in the longitudinal direction by adjusting the driving force distribution between the front wheels and the rear wheels, which are drive wheels. In this control method, the total driving force, which is the required driving force for the electric vehicle, is calculated based on the operation of the accelerator pedal. Also, based on this total driving force, there is an estimated acceleration, which is an estimated value of the acceleration that occurs when the electric vehicle is driven by the total driving force, or an estimated value, which is an estimated value of jerk, which is the time rate of change in acceleration. Jerk is calculated. Then, based on the estimated acceleration or the estimated jerk, an attitude control execution determination is made to turn on/off the attitude control.

FIG. 1 is an explanatory diagram showing a schematic configuration of an electric vehicle. FIG. 2 is an explanatory diagram showing a schematic structure of the chassis system. FIG. 3 is a graph showing the lower limit value of the pitch angle that an occupant of an electric vehicle can experience during acceleration. FIG. 4 is a block diagram showing the configuration of the controller 12 for attitude control. FIG. 5 is a block diagram showing the configuration of the attitude control execution determination section. FIG. 6 is a flowchart showing an operation related to turning on/off posture control in an electric vehicle. FIG. 7 is a time chart showing changes in parameters when posture control is switched from off to on. FIG. 8 is a block diagram showing the configuration of an attitude control execution determination section in the second embodiment. FIG. 9 is a flowchart showing the operation related to turning on/off posture control for the electric vehicle of the second embodiment. FIG. 10 is a block diagram showing a configuration for updating the coefficients of the approximation equation used to calculate running resistance. FIG. 11 is an explanatory diagram showing a specific mode of updating the coefficients of the approximation formula used to calculate running resistance. FIG. 12 is a flowchart showing the operation related to updating the coefficients of the approximation formula used to calculate running resistance.

Embodiments of the present invention will be described below with reference to the drawings.

[First embodiment]
<Configuration of electric vehicle>
FIG. 1 is an explanatory diagram showing a schematic configuration of an electric vehicle 100. The electric vehicle 100 is, for example, an electric vehicle, a hybrid vehicle, or the like, and is a vehicle that can drive or brake one or more drive wheels using an electric motor. In particular, in this embodiment, the electric vehicle 100 is a so-called 4WD (four wheel drive) vehicle, and the driving force generated in a plurality of drive wheels can be individually controlled (adjusted). Specifically, as shown in FIG. 1, electric vehicle 100 includes a front wheel drive system 10, a rear wheel drive system 11, and a controller 12.

The front wheel drive system 10 is a system that controls the front wheel 21, which is the first drive wheel. Front wheel drive system 10 includes a front inverter 22 and a front motor 23.

The front inverter 22 drives the front motor 23 by converting DC power output by a battery (not shown) into AC power and supplying the AC power to the front motor 23. Furthermore, when the front motor 23 is rotated by the front wheels 21, the front inverter 22 converts the AC regenerative power generated by the front motor 23 into DC power and inputs the DC power to the battery, thereby charging the battery. .

The front motor 23 is an electric motor that drives the front wheels 21. The front motor 23 is, for example, a three-phase AC synchronous motor. The torque generated by the front motor 23 is transmitted to the front wheels 21 via the front drive shaft 24, and generates a driving force (hereinafter referred to as front wheel driving force _FF ) at the front wheels 21.

The rear wheel drive system 11 is a system that controls the rear wheel 26, which is the second drive wheel. Rear wheel drive system 11 includes a rear inverter 27 and a rear motor 28.

The rear inverter 27 drives the rear motor 28 by converting the DC power output by the battery into AC power and supplying the AC power to the rear motor 28. Further, when the rear motor 28 is rotated by the rear wheels 26, the rear inverter 27 converts the AC regenerated power generated by the rear motor 28 into DC power and inputs the DC power to the battery, thereby charging the battery.

The rear motor 28 is an electric motor that drives the rear wheels 26. The rear motor 28 is configured by, for example, a three-phase AC synchronous motor similar to the front motor 23. The torque generated by the rear motor 28 is transmitted to the rear wheels 26 via the rear drive shaft 29, and generates a driving force (hereinafter referred to as rear wheel driving force _FR ) at the rear wheels 26.

The controller 12 is configured by one or more computers that control the operation of the electric vehicle 100. Controller 12 is programmed to control the operation of electric vehicle 100 at a predetermined control cycle. In the present embodiment, the controller 12 is a control device for the electric vehicle 100 that executes posture control to control the posture in the longitudinal direction by adjusting the distribution of driving force between the front wheels 21 and the rear wheels 26 that are drive wheels.

The controller 12 distributes the driving force (hereinafter referred to as the total driving force TQ) requested by, for example, the operation of an accelerator pedal (not shown) to the front wheels 21 and the rear wheels 26 that are driving wheels. Then, the controller 12 drives the front wheels 21 and the rear wheels 26 using the front wheel drive system 10 and the rear wheel drive system 11, respectively, so that a front wheel drive force F _F and a rear wheel drive force F _R are generated according to the distribution. Furthermore, in the present embodiment, the controller 12 is programmed to execute attitude control to control the longitudinal attitude of the electric vehicle 100 by adjusting the driving force distribution between the front wheels 21 and the rear wheels 26 as necessary. has been done.

When controlling the operation of the electric vehicle 100, the controller 12 can appropriately obtain various parameters representing the operating state of the electric vehicle 100, etc., using a sensor (not shown) or by calculation. For example, electric vehicle 100 includes an accelerator opening sensor (not shown) that detects accelerator opening _APO . Therefore, the controller 12 can appropriately acquire the accelerator opening degree _APO . The accelerator opening degree _APO is a parameter representing the amount of operation of the accelerator pedal. Further, the controller 12 appropriately acquires the vehicle speed VSP of the electric vehicle 100 using a sensor (not shown) or by calculation.

Further, in the present embodiment, the electric vehicle 100 includes an acceleration sensor (not shown) that measures acceleration generated in the electric vehicle 100 (hereinafter referred to as actual acceleration _Gact ). Therefore, the controller 12 can appropriately acquire the actual acceleration _Gact . In addition, the controller 12 can appropriately obtain jerk (hereinafter referred to as actual jerk J _act ), which is the time rate of change in acceleration generated in electric vehicle 100, by differentiating the actual acceleration G _act .

In addition, the controller 12 can appropriately acquire the current location of the electric vehicle 100 and the slope of the road surface on which the electric vehicle 100 travels (hereinafter referred to as road surface slope φ _LS ) from a car navigation system (not shown). Note that the road surface slope _φLS can be obtained by calculation based on the vehicle speed VSP and acceleration G of the electric vehicle 100, or changes thereof. In this embodiment, the road surface slope _φLS is obtained from the car navigation system.

<Principle of attitude control using driving force distribution>
FIG. 2 is an explanatory diagram showing a schematic structure of the chassis system. As shown in FIG. 2, the front wheels 21 are connected via a front suspension 31 to a vehicle shed 101, which is a portion of the vehicle body where a passenger compartment and the like are formed. Similarly, the rear wheels 26 are connected to the vehicle shed 101 via a rear suspension 32.

For example, when electric vehicle 100 is accelerated by front wheel driving force F _F , rear wheel driving force F _R , or both thereof, the load moves to the rear of electric vehicle 100 (to the negative side in the X direction). As a result, a moment is generated in the vehicle shed 101 around the center of gravity _OG that acts in a direction that increases the pitch angle _θP . Therefore, when electric vehicle 100 accelerates, in principle, electric vehicle 100 assumes a posture in which the front portion, which is the portion on the positive side in the X direction, rises (so-called nose-up posture).

On the other hand, the torque of the front motor 23 that generates the front wheel drive force _FF (hereinafter referred to as front torque) acts on the vehicle shed 101 via the front suspension 31. Specifically, the front torque generates a moment around the virtual center of rotation O _F that acts in a direction that reduces the pitch angle θ _P. That is, when electric vehicle 100 accelerates, the front torque suppresses nose up. Similarly, the torque of the rear motor 28 that generates the rear wheel drive force F _R (hereinafter referred to as rear torque) acts on the vehicle shed 101 via the rear suspension 32, and causes a pitch angle θ around the virtual center of rotation O _R. A moment is generated that acts in the direction of decreasing _P. Therefore, when electric vehicle 100 accelerates, rear torque suppresses nose up.

The magnitude of the effect of the front torque on suppressing nose-up during acceleration depends on the magnitude of the anti-scut angle _θF . Similarly, the magnitude of the effect of the rear torque to suppress nose-up during acceleration depends on the magnitude of the anti-scut angle θ _R. Therefore, by adjusting the drive force distribution between the front wheels 21 and the rear wheels 26 so that the distribution to the drive wheels with a relatively large anti-scut angle is increased, the nose-up can be suppressed while maintaining the total drive force. becomes larger. Therefore, in the present embodiment, the controller 12 performs attitude control that controls the attitude of the electric vehicle 100 in the longitudinal direction (i.e., the pitch angle θ _P or its variation) by adjusting the driving force distribution between the front wheels 21 and the rear wheels 26. Execute.

Note that the virtual center of rotation _OF is an instantaneous and virtual center of rotation that occurs in the vehicle body (in particular, the vehicle shed 101) due to the transmission of front torque, and is determined in advance by the specific configuration of the front suspension 31 and the like. Similarly, the virtual center of rotation _OR in the rear section is an instantaneous and virtual center of rotation that occurs in the vehicle body (particularly the vehicle shed 101) due to the transmission of rear torque, and is determined in advance by the specific configuration of the rear suspension 32, etc. Determined. Further, the anti-scut angle θ _F is the angle formed by a line connecting the rotation center of the front wheel 21 and the virtual rotation center _OF and a line parallel to the road surface in the XZ plane. Similarly, the anti-scut angle θ _R is the angle formed by a line connecting the rotation center of the rear wheel 26 and the virtual rotation center _OR and a line parallel to the road surface in the XZ plane.

In this embodiment, as shown in FIG. 2, the anti-scut angle θ _R of the rear suspension 32 is larger than the anti-scut angle θ _F of the front suspension 31. Therefore, for example, when suppressing or reducing the pitch angle θ _P from increasing during acceleration, the controller 12 relatively increases the driving force distribution to the rear wheels 26 .

Although the relationship between the configuration of the chassis system and attitude control during acceleration has been described here, the controller 12 executes attitude control by adjusting the driving force distribution between the front wheels 21 and the rear wheels 26 even during deceleration. However, during deceleration, contrary to the above, the electric vehicle 100 assumes a position where the front portion sinks (a so-called nose dive position), so the controller 12 controls the driving of the front wheels 21 and the rear wheels 26 accordingly. Adjust force distribution. Furthermore, hereinafter, unless otherwise specified, the attitude of electric vehicle 100 refers to the attitude in the front-rear direction, that is, the pitch angle θ _P. That is, posture control by adjusting the driving force distribution is control of pitch angle θ _P , control of pitch rate Δ _P , or control of pitch angle θ _P and pitch rate Δ _P. The pitch rate Δ _P is the time rate of change of the pitch angle θ _P.

<Target posture>
FIG. 3 is a graph showing the lower limit value LL of the pitch angle _θP that the occupant of the electric vehicle 100 can experience during acceleration. As shown in FIG. 3, there is a lower limit value LL for the pitch angle _θP that the occupant can experience during acceleration. That is, when the pitch angle θ _P is a small value that is about the lower limit value LL or less, the occupant has difficulty sensing the occurrence and fluctuation of the pitch angle θ _P.

This lower limit value LL depends on the pitch rate _ΔP . Specifically, the larger the pitch rate _ΔP is, the smaller the lower limit value LL of the perceivable pitch angle _θP is. That is, when the pitch rate Δ _P is large and the pitch angle θ _P changes sharply, the occupant senses the change in the pitch angle θ _P even if the pitch angle θ _P is small. On the other hand, when the pitch rate _ΔP is small and the pitch angle _θP changes slowly, the occupant has difficulty perceiving the change in the pitch angle _θP even if the pitch angle _θP is relatively large.

The occurrence or variation of the pitch angle θ _P usually causes little problem in stable running (running stability) of the electric vehicle 100, but may worsen the ride comfort of the electric vehicle 100. Therefore, the controller 12 executes posture control by adjusting the driving force distribution so that the pitch angle θ _P is approximately equal to or less than the lower limit value LL.

However, in this embodiment, an upper limit value UL that is predetermined through experiments, simulations, etc. is set for the pitch angle θ _P to be controlled by attitude control. The upper limit value UL is, for example, a constant value that does not depend on the pitch rate _ΔP .

Then, the controller 12 executes posture control by adjusting the driving force distribution when the pitch angle θ _P reaches a value in a range of not less than the lower limit value LL and not more than the upper limit value UL (a value within the region E _2a ). Thereby, the controller 12 controls the posture of the electric vehicle 100 in the longitudinal direction so that the pitch angle θ _P becomes a value within the range below the lower limit value LL (a value within the region E ₁ ). Typically, the target attitude of electric vehicle 100 is one in which pitch angle θ _P is zero. In the present embodiment, when performing attitude control, the controller 12 controls the pitch angle in the longitudinal direction so that the pitch angle θ _P is maintained at substantially zero or other predetermined angle (hereinafter referred to as target pitch angle θ _P ^* ). Control your posture. The predetermined angle for pitch angle θ _P may change depending on the specific running state of electric vehicle 100.

On the other hand, when the pitch angle θ _P is from the beginning a value in the range below the lower limit LL (a value in the area E ₁ ), or when the pitch angle θ _P is a value in the range exceeding the upper limit UL (a value in the area E _2b ) value), the controller 12 does not perform attitude control by adjusting the driving force distribution.

In other words, the controller 12 does not always execute attitude control, but performs an attitude control execution determination to turn attitude control on/off as necessary. Specifically, when it is determined as a result of the attitude control execution determination that attitude control needs to be executed, the controller 12 turns on attitude control. As a result, attitude control is started, or a state in which attitude control is being performed is maintained. On the other hand, when it is determined as a result of the attitude control execution determination that there is no need to execute attitude control, the controller 12 turns off attitude control. As a result, attitude control is stopped, or the state in which attitude control is stopped is maintained.

More specifically, when the pitch angle θ _P falls within the range of the region E _2a , the controller 12 determines that attitude control is necessary and turns on the attitude control. On the other hand, when the pitch angle θ _P reaches the value in the region E ₁ or the region E _2b , the controller 12 determines that there is no need to perform attitude control and turns off the attitude control.

As shown in FIG. 3, the pitch angle θ _P has a positive correlation with the acceleration G generated in the electric vehicle 100, and the pitch rate _ΔP has a positive correlation with the jerk J, which is the time rate of change of the acceleration G generated in the electric vehicle 100. be. Therefore, the controller 12 can specify the lower limit value LL of the pitch angle θ _P that can be felt by the occupant based on the acceleration G, the jerk J, or both of these. Therefore, the controller 12 can determine whether to perform attitude control based on the acceleration G, the jerk J, or both.

Since the controller 12 acquires the actual acceleration G _act and the actual jerk J _act , it can determine whether to perform attitude control based on the actual acceleration G _act and/or the actual jerk J _act . However, in this embodiment, the controller 12 performs attitude control execution determination based on the estimated acceleration G _est and/or the estimated jerk J _est instead of the actual acceleration G _act and/or the actual jerk J _act . This is for the purpose of starting attitude control without delay when it is necessary to perform attitude control. Estimated acceleration G _est is an estimated value of acceleration G that will occur in electric vehicle 100 from now on. Similarly, estimated jerk J _est is an estimated value of jerk J that will occur in electric vehicle 100 from now on.

Note that the lower limit value of the pitch angle θ _P that the occupant of the electric vehicle 100 can experience during acceleration or deceleration also changes depending on the road surface slope φ _LS . Specifically, when the road surface gradient φ _LS is large, it becomes difficult for the occupant to sense the pitch angle θ _P and its fluctuations. Therefore, the controller 12 can perform attitude control execution determination based not only on the estimated acceleration G _est and/or the estimated jerk J _est but also on the road surface gradient φ _LS . Specifically, the road surface gradient φ _LS is greater than a predetermined threshold value TH _LS (predetermined gradient), the road surface on which the electric vehicle 100 runs is steep, and the occupant can feel the pitch angle θ _P and its change. If it is difficult, the controller 12 determines that there is no need to perform attitude control and turns off attitude control. That is, when the road surface slope φ _LS is less than or equal to the threshold TH _LS and it is determined that attitude control is necessary based on the estimated acceleration G _est and/or the estimated jerk J _est , the controller 12 turns on the attitude control. Make it.

<Configuration for posture control>
FIG. 4 is a block diagram showing the configuration of the controller 12 for attitude control. As shown in FIG. 4, the controller 12 includes a total driving force calculation section 41, a basic distribution calculation section 42, an attitude control calculation section 43, a driving force setting section 44, a front motor control section 45, and a rear motor control section 46. .

The total driving force calculating section 41 calculates the total driving force TQ based on the operation of the accelerator pedal. Total driving force TQ is the required driving force for electric vehicle 100. For example, the total driving force calculation unit 41 has a map that associates the accelerator opening degree A _PO with the total driving force TQ, and calculates the total driving force TQ corresponding to the accelerator opening degree A _PO by referring to this map. .

Note that instead of calculating the total driving force TQ based on the accelerator opening degree A _PO as described above, the total driving force calculation unit 41 calculates the total driving force TQ based on the accelerator opening degree A PO as described above. Based on this, the total driving force TQ can be calculated. Since these systems are systems that replace the operation of the accelerator pedal by the driver, the calculation of the total driving force TQ performed by the total driving force calculation unit 41 based on the commands of these systems substantially does not require the operation of the accelerator pedal. It is a calculation based on operations.

The basic distribution calculation unit 42 distributes the total driving force TQ to the front wheels 21 and the rear wheels 26 according to the basic distribution. The basic distribution is a driving force distribution that is determined so as to maximize electric power consumption within a range that can ensure running stability, and is determined in advance through experiments, simulations, or the like. For example, when the front motor 23 and the rear motor 28 are of the same type and the electric vehicle 100 travels at a constant speed on a flat road, the basic distribution is front wheels: rear wheels = 50:50. The basic distribution may change depending on the specific running state (steering state, etc.) of electric vehicle 100.

In this embodiment, the basic distribution calculation unit 42 calculates the first front torque target value T _F1 ^* and the first rear torque target value T _R1 ^* based on the basic distribution and the total driving force TQ. The first front torque target value T _F1 ^* represents the front motor torque that causes the front wheels 21 to generate the front wheel driving force F _F according to the basic distribution. The first rear torque target value T _R1 ^* represents the rear torque that causes the rear wheels 26 to generate the rear wheel drive force F _R according to the basic distribution.

The attitude control calculation unit 43 determines whether or not attitude control is necessary, and calculates a correction distribution that is a driving force distribution for attitude control that should be set when attitude control is necessary. The correction distribution is determined so that the attitude of electric vehicle 100 asymptotically approaches or maintains the target attitude. Therefore, by distributing the driving force to the front wheels 21 and the rear wheels 26 according to the corrected driving force distribution, the attitude of the electric vehicle 100 is controlled to be the target attitude.

More specifically, the attitude control calculation unit 43 of this embodiment includes an attitude control execution determination unit 47 and a correction unit 48.

The attitude control execution determination unit 47 performs an attitude control execution determination for switching on/off of attitude control by adjusting the driving force distribution using feedforward control based on the total driving force TQ and the vehicle speed VSP. In the present embodiment, the attitude control execution determination unit 47 makes the attitude control execution determination based on the road surface slope _φLS in addition to the total driving force TQ and the vehicle speed VSP. The result of the attitude control execution determination is represented by an attitude control flag FLG. The attitude control flag FLG is, for example, a flag that becomes "1" (on) when execution of attitude control is necessary, and becomes "0" (off) when execution of attitude control is unnecessary.

The correction unit 48 corrects the driving forces of the front wheels 21 and rear wheels 26 (hereinafter referred to as basic driving forces) distributed according to the basic distribution, thereby increasing the driving forces of the front wheels 21 and rear wheels 26 for attitude control ( (hereinafter referred to as corrected driving force). In the present embodiment, the correction unit 48 determines the second front torque target value corresponding to the corrected driving force based on the first front torque target value T _F1 ^* corresponding to the basic driving force and the first rear torque target value T _R1 ^*. T _F2 ^* and second rear torque target value T _R2 ^* are calculated. The correction unit 48 calculates the corrected driving force by feedforward control based on, for example, a predetermined vehicle model of the electric vehicle 100. In this embodiment, the corrected distribution is determined by calculating a specific corrected driving force.

The driving force setting unit 44 sets the driving force generated by the front wheels 21 and the rear wheels 26 to either the basic driving force or the corrected driving force according to the attitude control flag FLG.

Specifically, when the attitude control execution determination determines that attitude control is not necessary and the attitude control flag FLG is "0", the driving force setting unit 44 sets the driving force to be generated by the front wheels 21 and the rear wheels 26. is set as the basic driving force. That is, when the attitude control flag FLG is "0", the driving force setting unit 44 inputs the first front torque target value T _F1 ^* to the front motor control unit 45, and inputs the first rear torque target value T _R1 ^* to the rear motor control unit 45. Input to the control unit 46. This turns off attitude control.

On the other hand, when it is determined by the attitude control execution determination that attitude control is necessary and the attitude control flag FLG is "1", the driving force setting unit 44 adjusts the driving force generated by the front wheels 21 and the rear wheels 26 to correct the driving force. Set to power. That is, when the attitude control flag FLG is "1", the driving force setting unit 44 inputs the second front torque target value T _F2 ^* to the front motor control unit 45, and inputs the second rear torque target value T _R2 ^* to the rear motor control unit 45. Input to the control unit 46. This turns on attitude control.

The front motor control unit 45 controls the front motor 23 via the front inverter 22 so that the driving force set by the driving force setting unit 44 is generated at the front wheels 21. When the first front torque target value T _F1 ^* that commands the basic driving force is input, the front motor control unit 45 causes the front motor 23 to generate a front torque corresponding to the first front torque target value T _F1 ^*. . On the other hand, when the second front torque target value T _F2 ^* that commands the corrected driving force for attitude control is input, the front motor control unit 45 causes the front motor 23 to adjust the second front torque target value T F2 * to the second front torque target value T _F2 ^* . Generates the corresponding front torque. Thereby, the front wheel drive force _FF is controlled to the basic drive force or the corrected drive force.

The rear motor control unit 46 controls the rear motor 28 via the rear inverter 27 so that the driving force set by the driving force setting unit 44 is generated at the rear wheel 26. When the first rear torque target value T _R1 ^* that commands the basic driving force is input, the rear motor control unit 46 causes the rear motor 28 to generate a rear torque corresponding to the first rear torque target value T _R1 ^* . On the other hand, when the second rear torque target value T _R2 ^* that commands the corrected driving force for posture control is input, the rear motor control unit 46 causes the rear motor 28 to generate a rear torque corresponding to the second rear torque target value T _R2 ^*. generate. Thereby, the rear wheel drive force _FR is controlled to the basic drive force or the corrected drive force.

Note that the front motor control section 45 and the rear motor control section 46 constitute a driving force control section that controls the driving force of the front motor 23 and the rear motor 28 according to the basic distribution or the corrected distribution.

FIG. 5 is a block diagram showing the configuration of the attitude control execution determination section 47. As shown in FIG. 5, the attitude control execution determination unit 47 includes a running resistance calculation unit 51, an acceleration estimation unit 52, a jerk estimation unit 53, a slope determination unit 54, a pitch state determination unit 55, and a flag setting unit 56. .

Running resistance calculating section 51 calculates running resistance RL [N] of electric vehicle 100 based on vehicle speed VSP [m/s]. Running resistance RL is composed of air resistance, rolling resistance, acceleration resistance, etc., and can be approximated by a quadratic function of vehicle speed VSP as shown in equation (1) below. The coefficient A ₀ of the second-order term, the coefficient A ₁ of the first-order term, and the coefficient A ₂ representing a term (constant term) that does not depend on the vehicle speed VSP may be determined in advance by, for example, experiments or simulations. can. Therefore, the running resistance calculation unit 51 calculates the running resistance RL according to the vehicle speed VSP using the coefficients A ₀ , A ₁ , and A ₂ of each order.

The acceleration estimation unit 52 calculates the estimated acceleration G _est [m/sec ² ] based on the total driving force TQ [Nm] and the running resistance RL. The acceleration estimation unit 52 calculates the estimated acceleration G _est according to the equation of motion. That is, the acceleration estimating unit 52 calculates the estimated acceleration _Gest based on the total driving force TQ, the running resistance RL, and the known weight of the electric vehicle 100 (hereinafter referred to as vehicle weight M), as shown in the following formula (2). Estimated acceleration G _est is calculated using [kg], gravitational acceleration g [m/sec ² ], and road surface gradient φ _LS [deg]. Note that the estimated acceleration G _est calculated by the acceleration estimation unit 52 is an estimated value of the acceleration G that occurs when the electric vehicle 100 is driven with the total driving force TQ.

The jerk estimation unit 53 calculates the estimated jerk J _est [m/sec ³ ] based on the estimated acceleration G _est . Specifically, the jerk estimating unit 53 calculates the estimated jerk _J est by differentiating the estimated acceleration G _est with respect to time, as shown in Equation (3) below. Note that the estimated jerk J _est calculated by the jerk estimating unit 53 is an estimated value of the temporal change rate (jerk J) of the acceleration G that occurs when the electric vehicle 100 is driven with the total driving force TQ.

The slope determination unit 54 determines whether attitude control is possible based on the road surface slope _φLS . Specifically, the slope determination unit 54 compares the road surface slope _φLS with a predetermined threshold value _THLS . Then, when the road surface slope φ _LS is less than or equal to the threshold value TH _LS , the slope determination unit 54 determines that attitude control can be executed. On the other hand, when the road surface slope φ _LS is larger than the threshold value TH _LS , the slope determination unit 54 determines that execution of attitude control is unnecessary. The threshold value TH _LS determined for the road surface slope φ _LS is determined by adaptation through experiment, simulation, or the like.

Pitch state determination unit 55 determines whether attitude control is necessary based on the state of pitch angle θ _P or its fluctuation that occurs when electric vehicle 100 is driven with total driving force TQ. The pitch state determining unit 55 determines whether attitude control is necessary based on the estimated acceleration G _est that has a positive correlation with the pitch angle θ _P , the estimated jerk J _est that has a positive correlation with the pitch rate Δ _P , or both of these. can be determined. In this embodiment, the pitch state determination unit 55 determines whether attitude control is necessary based on the estimated acceleration G _est and the estimated jerk J _est .

Specifically, the pitch state determination unit 55 determines that the combination of pitch angle θ _P and pitch rate Δ _P (hereinafter referred to as pitch state) corresponding to estimated acceleration G _est and estimated jerk J _est is such that the occupant can experience it. It is determined whether or not it is within a range that requires control. That is, the pitch state determination unit 55 determines whether the pitch state that occurs is within the range E _2a (see FIG. 3). Then, when the pitch state that occurs is within the range _E2a , the pitch state determination unit 55 determines that attitude control needs to be executed (turned on). On the other hand, when the pitch state that occurs is not within the range _E2a , the pitch state determination unit 55 determines that execution of attitude control is not required.

The above determination by the pitch state determining unit 55 is synonymous with determining whether the pitch angle θ _P is greater than or equal to the lower limit value LL and less than or equal to the upper limit value UL. Therefore, the pitch state determination unit 55, for example, compares the pitch angle θ _P corresponding to the estimated acceleration G _est with the lower limit value LL that is preset according to the pitch rate Δ _P corresponding to the estimated jerk J _est . , it is possible to determine whether or not attitude control is necessary.

In this embodiment, the pitch state determining unit 55 determines whether or not posture control is necessary, particularly in a simple or approximate manner as follows. That is, the pitch state determination unit 55 sets a predetermined threshold TH _G (acceleration threshold) for the estimated acceleration G _est , and sets a predetermined threshold TH _J (jerk threshold) for the estimated jerk J _est . , determine areas where there is a particularly high need for postural control. Then, when the estimated acceleration G _est is equal to or greater than the threshold value TH _G (and equal to or less than the upper limit value UL), and the estimated jerk J _est is equal to or greater than the threshold value TH _J , the pitch state determination unit 55 executes attitude control (on ) is determined to be necessary. On the other hand, when the estimated acceleration G _{est is} smaller than the threshold TH _G or when the estimated jerk J _est is smaller than the threshold TH _J , the pitch state determination unit 55 determines that execution of attitude control is not required.

Note that the threshold value TH _J set for the estimated jerk J _est can be a variable threshold value that changes depending on the estimated acceleration G _est . Similarly, the threshold value TH _G set for the estimated acceleration G _est can be a variable threshold value that changes depending on the estimated jerk J _est .

Furthermore, the range of the pitch angle θ _P and the like in which the pitch state determination unit 55 determines that execution (on) of posture control is necessary can be set substantially arbitrarily. Therefore, the pitch state determination unit 55 performs attitude control when the estimated acceleration G _est satisfies either the threshold value TH _G (and the upper limit value UL or less) or the estimated jerk J _est satisfies the threshold value TH _J or more. It may be determined that it is necessary to execute (turn on). In this case, when the estimated acceleration G _est is smaller than the threshold TH _G and the estimated jerk J _est is smaller than the threshold TH _J , the pitch state determination unit 55 determines that execution of attitude control is not required.

The flag setting unit 56 sets the attitude control flag FLG based on the determination results by the slope determining unit 54 and the pitch state determining unit 55. Specifically, when the gradient determining unit 54 determines that attitude control is not required to be executed, the flag setting unit 56 sets the attitude control flag FLG to “0” (off) regardless of the determination result by the pitch state determining unit 55. Set. When the slope determining unit 54 determines that attitude control is executable, the flag setting unit 56 sets the attitude control flag FLG based on the determination result by the pitch state determining unit 55. That is, when the gradient determining unit 54 determines that attitude control can be executed and the pitch state determining unit 55 determines that attitude control needs to be executed (turned on), the flag setting unit 56 sets the attitude control flag. Set FLG to "1" (on). On the other hand, when the slope determining section 54 determines that attitude control is executable, but the pitch state determining section 55 determines that attitude control does not need to be executed, the flag setting section 56 sets the attitude control flag FLG to "0" ( Off).

<Effect>
Hereinafter, the attitude control of the electric vehicle 100 configured as described above, particularly the operation related to turning on/off the attitude control, will be explained.

FIG. 6 is a flowchart showing operations related to turning on/off posture control in electric vehicle 100. As shown in FIG. 6, upon acquiring the accelerator opening _{degree APO} in step S10, the total driving force calculation unit 41 calculates the total driving force TQ based on the acquired accelerator opening degree _APO in step S11. Next, in step S12, running resistance calculating section 51 calculates running resistance RL of electric vehicle 100 based on total driving force TQ and vehicle speed VSP. Then, in step S13, the acceleration estimating unit 52 calculates the estimated acceleration G _est based on the running resistance RL, and in step S14, the jerk estimating unit 53 calculates the estimated jerk J _est using the estimated acceleration G _est . do.

Thereafter, in step S15, the slope determination unit 54 acquires the road surface slope φ _LS , and determines whether attitude control is possible based on the acquired road surface slope φ _LS . When the road surface gradient φ _LS is larger than the threshold value TH _LS and the occupant cannot experience the pitch angle θ _P and its fluctuations due to the road surface gradient φ _LS , the process proceeds to step S19, and the attitude control is stopped or the attitude control is stopped. The stopped state is maintained. On the other hand, if the road surface gradient φ _LS is less than or equal to the threshold TH _LS and the occupant can experience the pitch angle θ _P and its fluctuations, which may worsen the ride comfort of the electric vehicle 100, the process proceeds to step S16, and the process proceeds to step S16. The necessity of attitude control is determined based on the pitch state (θ _P , Δ _P ).

In step S16, the pitch state determination unit 55 compares the estimated acceleration G _est with the threshold value TH _G. When the estimated acceleration G _est is equal to or greater than the threshold TH _G , the process proceeds to step S17, and the pitch state determination unit 55 further compares the estimated jerk J _est with the threshold TH _J. Then, when the estimated jerk J _est is greater than or equal to the threshold TH _J , that is, when the estimated acceleration G _est and the estimated jerk J _est are both greater than or equal to the respective thresholds TH _G and TH _J , execution (on) of attitude control is performed. It is determined that it is necessary. Therefore, the process advances to step S18, and attitude control is executed, or execution of attitude control is maintained.

On the other hand, when the estimated acceleration G _{est is} smaller than the threshold TH _G in step S16, or when the estimated jerk J _est is smaller than the threshold TH _J in step S17, it is determined that attitude control does not need to be executed. Therefore, the process proceeds to step S19, and the attitude control is stopped or the stopped state is maintained.

FIG. 7 is a time chart showing changes in parameters when posture control is switched from off to on. FIG. 7(A) shows changes in vehicle speed VSP. FIG. 7(B) shows the transition of the accelerator opening degree _APO . FIG. 7(C) shows the transition of the total driving force TQ. FIG. 7(D) shows a change in acceleration G of electric vehicle 100. In FIG. 7(D), the solid line indicates the estimated acceleration G _est , and the one-dot chain line indicates the actual acceleration G _act . FIG. 7(E) shows changes in jerk J of electric vehicle 100. In FIG. 7(E), the solid line indicates the estimated jerk J _est , and the dashed line indicates the actual jerk J _act .

FIG. 7(F) shows the transition of the attitude control flag FLG. In FIG. 7(F), the solid line indicates the attitude control flag FLG in this embodiment, in which the attitude control execution determination is performed by feedforward control based on the estimated acceleration G _est and the estimated jerk J _est . In FIG. 7(F), the dashed-dotted line indicates the comparative example in which the attitude control execution determination is performed by feedback control based on the actual acceleration G _act and actual jerk J _act , or the pitch angle θ _P and pitch rate Δ _P that actually occurred. Indicates the attitude control flag FLG. Note that in both the present embodiment and the comparative example, attitude control is performed by feedforward control. FIG. 7(G) shows the transition of the pitch angle _θP . In FIG. 7(G), the solid line indicates the pitch angle θ _P when performing attitude control execution determination in this embodiment. In FIG. 7(G), the dashed line indicates the pitch angle θ _P of the comparative example. Note that the horizontal axis of each time chart in FIG. 7 is time [sec].

As shown in FIG. 7(A), electric vehicle 100 is initially in a stopped state. Then, as shown in FIG. 7(B), when the accelerator pedal is depressed from time _t1 and the accelerator opening degree _APO increases in steps, the total driving force is increased accordingly, as shown in FIG. 7(C). TQ occurs and increases. As a result, as shown in FIG. 7A, the vehicle speed VSP of the electric vehicle 100 increases from time _t4 , which is delayed by a predetermined amount from time _t1 due to the control delay. The control delay is a control delay due to communication delay, torque reaction delay of the front motor 23 and rear motor 28, and the like.

At this time, as shown in FIG. 7(D), the estimated acceleration G _est begins to rise from time t ₁ without substantial delay. Therefore, as shown in FIG. 7(E), the estimated jerk J _est also occurs from time t ₁ without substantial delay. Further, here, as shown in FIG. 7(D), the estimated acceleration G _est is assumed to be equal to or greater than the threshold value TH _G at time t ₂ between time t ₁ and time t ₄ . As shown in FIG. 7E, the estimated jerk J _est assumes a value greater than or equal to the threshold value TH _J at time t ₃ between time t ₂ and time t ₄ . Therefore, at time _t3 , both the estimated acceleration G _est and the estimated jerk J _est become equal to or greater than the threshold values TH _G and TH _J. Therefore, as shown in FIG. 7(F), in this embodiment (solid line), the attitude control flag FLG transitions from "0" (off) to "1" (on) at time _t3 , and is started.

On the other hand, as shown in FIG. 7(D), the actual acceleration _Gact starts to increase from time _t4 due to the control delay. Therefore, as shown in FIG. 7E, the actual jerk J _act also occurs from time _t4 due to the control delay. Further, as shown in FIG. 7(D), the time _t5 at which the actual acceleration _Gact becomes equal to or greater than the threshold value _THG is after the time _t4 . Then, as shown in FIG. 7(E), the actual jerk J _act exceeds the threshold value TH _J and is further delayed. Therefore, at time _t6 , both the actual acceleration G _act and the actual jerk J _act become equal to or greater than the respective threshold values TH _G and TH _J. Therefore, as shown in FIG. 7(F), in the comparative example (dotted chain line), the attitude control flag FLG changes from "0" (off) to "1" (on) at least at time _t6 after time _t4 . ) and attitude control is started.

Therefore, when comparing the present embodiment and the comparative example, in the present embodiment, the attitude control execution determination is completed at time _t3 before acceleration G etc. actually occur in the electric vehicle 100, and the electric vehicle 100 is actually accelerated. When G or the like occurs, attitude control has started. On the other hand, in the comparative example, the attitude control execution determination cannot be completed before time _t4 when electric vehicle 100 actually experiences acceleration G or the like. Therefore, in the comparative example, after acceleration G etc. actually occur in electric vehicle 100, it is inevitable that a delay equivalent to at least a control delay will occur before attitude control is started.

As a result, as shown in FIG. 7(G), in this embodiment (solid line), after time t ₄ when the pitch angle θ _P changes, the pitch rate Δ _P (inclination) is quickly suppressed, and The pitch angle θ _P can be converged to the target pitch angle θ _P ^* . That is, in this embodiment, the attitude control can be made to function from the beginning when the pitch angle θ _P fluctuates.

On the other hand, in the comparative example (broken line), after time _t4 until time _t6 when attitude control is started, the pitch angle _θP increases at a steep pitch rate _ΔP and reaches the target pitch angle _θP ^* . Get closer. Thereafter, attitude control is started at time _t6 , and the pitch angle θ _P converges to the target pitch angle θ _P ^* . Therefore, in the comparative example, most of the fluctuations in pitch angle θ _P occur during the period from time t ₄ to time t ₆ when attitude control is not working. That is, in the comparative example, attitude control is substantially not done in time.

[Second embodiment]
In the first embodiment, the attitude control execution determination _unit 47 determines whether or not attitude control is necessary based on the estimated acceleration G _est _and the estimated jerk J _est . It is also possible to determine whether or not posture control is necessary based on either. However, the specific configuration of the attitude control execution determination unit 47 for determining whether or not attitude control is necessary is not limited to this. The attitude control execution determination unit 47 determines whether or not attitude control is necessary based on the actual acceleration G _act , the actual jerk J _act , or both of these in addition to the estimated acceleration G _est and/or the estimated jerk J _est be able to. In the second embodiment below, as an example, the attitude control execution determination unit 47 determines whether or not attitude control is necessary based on the estimated acceleration G _est and the estimated jerk J _est , and the attitude control execution determination unit 47 based on the actual acceleration G _act and the actual jerk J _act . An embodiment will be described in which the necessity of attitude control is determined comprehensively by combining the determination of necessity of control.

FIG. 8 is a block diagram showing the configuration of the attitude control execution determination unit 47 in the second embodiment. As shown in FIG. 8, the attitude control execution determination unit 47 of the second embodiment includes a running resistance calculation unit 51, an acceleration estimation unit 52, a jerk estimation unit 53, and a gradient determination unit 54, which are similar to those of the first embodiment. Be prepared. The attitude control execution determination section 47 of the second embodiment includes a first pitch state determination section 201 and a second pitch state determination section 202 instead of the pitch state determination section 55 of the first embodiment. Furthermore, the attitude control execution determination section 47 of the second embodiment includes a flag setting section 203 instead of the flag setting section 56 of the first embodiment.

Similar to the pitch state determining unit 55 of the first embodiment, the first pitch state determining unit 201 determines the pitch state (θ _P , Δ _P ) that is predicted to occur based on the estimated acceleration G _est and the estimated jerk J _est . Accordingly, it is determined whether or not attitude control needs to be executed. Here, the first pitch state determination unit 201 determines whether or not attitude control is necessary using a simple or approximate method as in the first embodiment. Specifically, the first pitch state determination unit 201 presets threshold values TH _G and TH _J for the estimated acceleration G _est and the estimated jerk J _est , respectively. Then, when the estimated acceleration G _est is equal to or greater than the threshold value TH _G (and equal to or less than the upper limit value UL), and the estimated jerk J _est is equal to or greater than the threshold value TH _J , the first pitch state determination unit 201 executes attitude control. (On) is determined to be necessary. On the other hand, when the estimated acceleration G _{est is} smaller than the threshold value TH _G or when the estimated jerk J _est is smaller than the threshold value TH _J , the first pitch state determination unit 201 determines that execution of attitude control is not required.

The second pitch state determination unit 202 acquires the actual acceleration G _act and the actual jerk J _act , and determines based on these whether or not attitude control needs to be executed. That is, the second pitch state determination unit 202 determines whether or not attitude control is necessary, depending on the pitch state (θ _P , Δ _P ) that actually occurs. Except for using the actual acceleration G _act and the actual jerk J _act instead of the estimated acceleration G _est and the estimated jerk J _est , the second pitch state determination unit 202 performs the determination of the necessity of attitude control in the same manner as in the first embodiment. This can be performed using a method similar to that used by the pitch state determining section 55 or the first pitch state determining section 201 described above.

Here, the second pitch state determining section 202 uses the same simple or approximate method as the specific necessity determining method executed by the first pitch state determining section 201 to determine the actual acceleration G _act and the actual jerk J _act . Based on this, it is determined whether attitude control is necessary. That is, the second pitch state determination unit 202 sets threshold values TH _G and TH _J for the actual acceleration G _act and the actual jerk J _act , respectively. The threshold values TH _G and TH _J set for the actual acceleration G _act and the actual jerk J _act can be different values from the threshold values TH G and TH _J set for the estimated acceleration G _est and the estimated jerk _J _est . However, here, for simplicity, the thresholds TH _G and TH _J are set to have the same value. Then, when the actual acceleration G _act is equal to or greater than the threshold value TH _G (and equal to or less than the upper limit value UL), and the actual jerk J _act is equal to or greater than the threshold value TH _J , the second pitch state determination unit 202 executes attitude control. (On) is determined to be necessary. On the other hand, when the actual acceleration G _act is smaller than the threshold value TH _G or when the actual jerk J _act is smaller than the threshold value TH _J , the second pitch state determination unit 202 determines that attitude control does not need to be executed.

The flag setting unit 203 sets the attitude control flag FLG based on the determination results of the slope determining unit 54, the first pitch state determining unit 201, and the second pitch state determining unit 202.

Specifically, when the slope determining unit 54 determines that attitude control is not required, the flag setting unit 203 determines that the attitude control is not necessary, regardless of the determination results of the first pitch state determining unit 201 and the second pitch state determining unit 202. Set control flag FLG to "0" (off).

On the other hand, when the slope determining unit 54 determines that attitude control is executable, the flag setting unit 203 sets the attitude control flag FLG based on the determination results by the first pitch state determining unit 201 and the second pitch state determining unit 202. Set. Specifically, when the gradient determining unit 54 determines that attitude control is executable and the first pitch state determining unit 201 determines that attitude control needs to be executed (turned on), the flag setting unit 203 , the attitude control flag FLG is set to "1" (on) regardless of the determination result of the second pitch state determination unit 202. Further, if the slope determining unit 54 determines that attitude control is executable, but the first pitch state determining unit 201 determines that attitude control does not need to be executed, the flag setting unit 203 determines that the second pitch state determining unit 202 When it is determined that attitude control needs to be executed (on), the attitude control flag FLG is set to "1" (on). Then, when the gradient determining unit 54 determines that attitude control is executable, but both the first pitch state determining unit 201 and the second pitch state determining unit 202 determine that attitude control does not need to be executed, the flag setting unit 203 sets the attitude control flag FLG to "0" (off).

That is, when the gradient determining unit 54 determines that attitude control can be executed, the flag setting unit 203 determines whether either the first pitch state determining unit 201 or the second pitch state determining unit 202 executes attitude control (on). When it is determined that this is necessary, the attitude control flag FLG is set to "1" (on). Then, when the gradient determining unit 54 determines that attitude control is executable, and both the first pitch state determining unit 201 and the second pitch state determining unit 202 determine that attitude control does not need to be executed, , set the attitude control flag FLG to "0" (off).

Hereinafter, the operation related to turning on/off the posture control for the electric vehicle 100 of the second embodiment configured as described above will be explained.

FIG. 9 is a flowchart illustrating an operation related to turning on/off posture control for electric vehicle 100 according to the second embodiment. As shown in FIG. 9, in step S20, the total driving force calculation unit 41 acquires the accelerator opening degree A _PO , and the second pitch state determination unit 202 acquires the actual acceleration G _act and the actual jerk J _act . Next, in step S21, the total driving force calculating section 41 calculates the total driving force TQ based on the accelerator opening degree APO, and the running resistance calculating section 51 calculates the driving force of the electric vehicle 100 based on the total driving force TQ and the vehicle speed VSP. Calculate resistance RL. Further, in step S21, the acceleration estimating section 52 calculates the estimated acceleration G _est based on the running resistance RL, and the jerk estimating section 53 calculates the estimated jerk J _est using the estimated acceleration G _est .

Thereafter, in step S22, the slope determination unit 54 determines whether attitude control is possible based on the road surface slope _φLS . When the road surface gradient φ _LS is larger than the threshold value TH _LS and the occupant cannot experience the pitch angle θ _P and its fluctuations due to the road surface gradient φ _LS , the process proceeds to step S28, and the attitude control is stopped or the attitude control is stopped. The stopped state is maintained. On the other hand, if the road surface gradient φ _LS is less than or equal to the threshold TH _LS and there is a possibility that the occupant can experience the pitch angle θ _P and its fluctuations, thereby worsening the ride comfort of the electric vehicle 100, the process proceeds to step S23, and the process proceeds to step S23. The necessity of attitude control is determined based on the pitch state (θ _P , Δ _P ) that is predicted to occur or the pitch state (θ _P , Δ _P ) that actually occurred.

In step S23, the first pitch state determination unit 201 compares the estimated acceleration G _est with the threshold value TH _G. When the estimated acceleration G _est is equal to or greater than the threshold TH _G , the process proceeds to step S24, and the first pitch state determination unit 201 further compares the estimated jerk J _est with the threshold TH _J. Then, when the estimated jerk J _est is greater than or equal to the threshold TH _J , that is, when the estimated acceleration G _est and the estimated jerk J _est are both greater than or equal to the respective thresholds TH _G and TH _J , execution (on) of attitude control is performed. It is determined that it is necessary. Therefore, the process advances to step S27, and attitude control is executed, or execution of attitude control is maintained.

On the other hand, when the estimated acceleration G _{est is} smaller than the threshold TH _G in step S23, or when the estimated jerk J _est is smaller than the threshold TH _J in step S24, the process advances to step S25, and the second pitch state determination unit 202 The actual acceleration _Gact is compared with a threshold value _THG . Then, when the actual acceleration G _act is equal to or greater than the threshold value TH _G , the process proceeds to step S26, and the second pitch state determination unit 202 further compares the actual jerk J _act with the threshold value TH _J.

When the actual acceleration G _act is equal to or greater than the threshold value TH _G in step S25, and the actual jerk J _act is equal to or greater than the threshold value TH _J in step S26, it is determined that attitude control needs to be executed (on). Therefore, the process advances to step S27, and attitude control is executed, or execution of attitude control is maintained. In other words, even if it is determined as a result of the determination based on the estimated acceleration G _est and the estimated jerk J _est that it is not necessary to execute attitude control, as a result of the determination based on the actual acceleration G _act and the actual jerk J _act , the execution of attitude control is not necessary. When it is determined that (on) is necessary, attitude control is turned on.

On the other hand, when the actual acceleration G _act is smaller than the threshold value TH _G in step S25, or when the actual jerk J _act is smaller than the threshold value TH _J in step S26, it is determined that attitude control does not need to be executed. Therefore, the process proceeds to step S28, and the attitude control is stopped, or the stopped state of the attitude control is maintained. That is, as a result of the determination based on the estimated acceleration G _est and the estimated jerk J _est , it is determined that the execution of attitude control is not required, and as a result of the determination based on the actual acceleration G _act and the actual jerk J _act , it is determined that the execution of attitude control is not required. If it is determined that it is not required, attitude control is turned off.

In this way, if the determination based on the estimated acceleration G _est and estimated jerk J _est is combined with the determination based on the actual acceleration G _act and actual jerk J _act to determine whether or not attitude control is necessary, at least the pitch angle θ When _P and its fluctuations actually occur, attitude control functions reliably. For example, there is a change in the vehicle weight M or a change in air resistance due to the installation of aftermarket parts, which causes a non-negligible calculation error in the running resistance RL required to calculate the estimated acceleration G _est and estimated jerk J _est . . Then, the pitch angle θ _P and its fluctuation may occur before it is determined that it is necessary to execute (turn on) attitude control based on the estimated acceleration G _est and the estimated jerk J _est . At this time, as described above, if the attitude control necessity determination based on the actual acceleration G _act and the actual jerk J _act is used in combination, the pitch angle θ _P is such that it is necessary to execute (turn on) the attitude control. Attitude control can be activated when this change actually occurs.

[Third embodiment]
In the first and second embodiments described above, the estimated acceleration G _est and the estimated jerk J _est are calculated based on the running resistance RL, and the running resistance RL is approximated by a quadratic function of the vehicle speed VSP. The coefficients A ₀ , A ₁ , and A ₂ of each order in the approximate expression used to calculate the running resistance RL are determined in advance by experiment, simulation, or the like. However, running resistance RL may change depending on the specific usage state of electric vehicle 100. For example, when vehicle weight M changes, or when air resistance changes due to installation of aftermarket parts, etc., running resistance RL of electric vehicle 100 changes. As described above, in order to maintain the accuracy of attitude control execution determination using the estimated acceleration G _est and estimated jerk J _est when there is a significant change in the running resistance RL, the predetermined coefficients A ₀ and A _{1 are} , _A2 , and accurately calculate running resistance RL according to the specific usage state of electric vehicle 100. In the following third embodiment, an example will be described in which coefficients A ₀ , A ₁ , and A ₂ used for calculating running resistance RL are updated according to a specific usage state of electric vehicle 100.

FIG. 10 is a block diagram showing a configuration for updating coefficients A ₀ , A ₁ , and A ₂ of the approximate expression used to calculate running resistance RL. As shown in FIG. 10, the controller 12 can include a coefficient update section 301 in addition to the configuration of the first embodiment and/or the second embodiment.

The coefficient update section 301 includes a flat road determination section 311 , a steady running determination section 312 , a first error calculation section 313 , a running resistance storage section 314 , a second error calculation section 315 , and a coefficient update section 316 .

The flat road determination unit 311 determines whether the electric vehicle 100 is traveling on a flat road based on the road surface slope _φLS . That is, flat road determining section 311 determines whether electric vehicle 100 is traveling in a state where running resistance RL does not include gradient resistance. Specifically, the flat road determination unit 311 determines that the electric vehicle 100 runs on a flat road when the road surface gradient φ _LS is close to zero with a predetermined error of ±φ ₀ or less (−φ ₀ ≦φ _LS ≦+φ ₀ ). It is determined that the

Steady running determination unit 312 determines whether electric vehicle 100 is running at a constant speed (so-called road running) without accelerating or decelerating. That is, steady running determination section 312 determines whether electric vehicle 100 is running in a state where running resistance RL does not include resistance due to acceleration or deceleration. In this embodiment, the steady running determination unit 312 acquires the actual acceleration _Gact , and determines whether or not steady running is continuing based on the actual acceleration _Gact . Specifically, when the actual acceleration G _act is less than or equal to a predetermined error of ±G ₀ (-G ₀ ≦G _act ≦+G ₀ ), it is determined that the electric vehicle 100 is running steadily.

The first error calculation unit 313 calculates a first error G _err (acceleration estimation error) which is an error between the estimated acceleration G _est and the actual acceleration G _act . The first error calculation unit 313 obtains the estimated acceleration _Gest from the acceleration estimation unit 52. However, the first error calculation unit 313 may calculate the estimated acceleration G _est using the same method as the acceleration estimation unit 52. In this embodiment, the first error calculation unit 313 calculates the first error G _err by subtracting the actual acceleration G _at from the estimated acceleration G _est .

Furthermore, the first error calculation unit 313 counts a period (hereinafter referred to as duration τ _err ) during which a significant error continues to occur in the estimated acceleration G _est based on the calculated first error G _err . Specifically, the first error calculation unit 313 compares the calculated first error G _err with a predetermined threshold TH _err1 , and calculates the time period during which the first error G _err is equal to or greater than the threshold TH _err1 as a duration τ. Set to _err .

The running resistance storage unit 314 at least temporarily stores the running resistance RL when the electric vehicle 100 is steadily running on a flat road in association with the vehicle speed VSP at that time. Specifically, the running resistance storage unit 314 stores the information that, during steady running on a flat road, the duration τ _err during which the first error G _err is equal to or greater than the threshold value TH _err1 becomes equal to or greater than the threshold value τ ₀ predetermined by adaptation. In this case, the total driving force TQ at that time is obtained. The running resistance storage unit 314 then stores the acquired total driving force TQ as the actual running resistance RL during steady running on a flat road (hereinafter referred to as actual running resistance RL _act ) in association with the vehicle speed VSP.

The second error calculation unit 315 calculates a second error RL _err (running resistance error) which is an error between the actual running resistance RL _act stored in the running resistance storage unit 314 and the running resistance RL calculated by the running resistance calculation unit 51. Calculate. The calculation of the second error RL _err is performed for each vehicle speed VSP. Further, the second error calculation unit 315 evaluates the dispersion of the second error RL _err by calculating the variance of the second error RL _err and other statistical values.

The coefficient update unit 316 updates (calculates) all or part of the coefficients A ₀ , A ₁ , and A ₂ that the running resistance calculation unit 51 uses to calculate the running resistance RL, based on the actual running resistance RL _act . Further, the coefficient updating unit 316 corrects the pre-stored coefficients A ₀ , A ₁ , A ₂ or calculates new coefficients A ₀ , A ₁ , A ₂ , and updates the pre-stored coefficients. By replacing A ₀ , A ₁ , and A ₂ , the coefficients A ₀ , A ₁ , and A ₂ used for calculating the running resistance RL are updated.

In the present embodiment, the coefficient update unit 316 is configured to update the coefficient when the running resistance storage unit 314 stores at least three or more actual running resistances RL _act and the variation in the second error RL _err is less than or equal to a predetermined threshold TH _err2 . Then, the coefficient update unit 316 updates the coefficient _A2 of the constant term. Specifically, the coefficient update unit 316 updates the coefficient A ₂ of the constant term by correcting the coefficient A ₂ of the constant term based on the second error RL _err . For example, the coefficient updating unit 316 corrects the coefficient A ₂ of the constant term by adding the average value of the second error RL _err to the coefficient A ₂ of the previous constant term.

Further, in this embodiment, although the running resistance storage unit 314 stores at least three or more actual running resistances RL _act , when the variation in the second error RL _err is larger than the threshold TH _err2 , the coefficient updating unit 316 updates the coefficients A ₀ and A ₁ of the quadratic and first order terms. Specifically, the coefficient updating unit 316 updates the coefficients A ₀ and A ₁ of the quadratic and primary terms by newly calculating them based on the actual running resistance RL _act . For example, the coefficient updating unit 316 uses the previous value as the coefficient A ₂ of the constant term, and calculates a quadratic regression curve based on the actual running resistance RL _act , thereby updating the coefficient A ₀ of the new quadratic and first-order terms. , A ₁ is calculated.

FIG. 11 is an explanatory diagram showing a specific manner of updating the coefficients A ₀ , A ₁ , and A ₂ of the approximate expression used to calculate the running resistance RL. In FIG. 11, a data set indicated by a legend circle (◯) indicates running resistance RL calculated using coefficients A ₀ , A ₁ , and A ₂ stored in advance in the initial state of electric vehicle 100. In addition, each data set indicated by a triangle (△) and a square (□) legend represents the running resistance RL stored in the running resistance storage unit 314 in independent running scenes in which the specific usage conditions of the electric vehicle 100 are different. show.

As shown in FIG. 11, when the running resistance RL indicated by the triangle (△) legend is obtained by steady running on a flat road, the second errors RL _err at each data point are E _1A , E _1B , and E It is _1C . These second errors RL _err (=E _1A , E _1B , E _1C ) are all approximately the same size, and the variation thereof is less than or equal to the threshold value TH _err2 . Therefore, the coefficient update unit 316 adds the average value of these second errors RL _err , that is, the average value of E _1A , E _1B , and E _1C to the previous coefficient A ₂ to update the coefficient A of the constant term. Update ₂ . This causes the quadratic curve that approximates the running resistance RL to be translated from a solid line to a broken line. Therefore, updating the coefficient _A2 of the constant term is suitable when, for example, a running resistance component other than air resistance (rolling resistance, etc.) changes due to a change in vehicle weight M or the like.

When the running resistance RL indicated by the rectangle (□) legend is obtained by steady running on a flat road, the second error RL _err at each data point is E _2A , E _2B , and E _2C . The magnitudes of these second errors RL _err (=E _2A , E _2B , E _2C ) are different from each other, and the dispersion thereof is larger than the threshold value TH _err2 . Therefore, the coefficient update unit 316 maintains the coefficient A ₂ of the constant term and calculates the quadratic regression curve of the data points indicated by the rectangle (□) legend, thereby increasing the coefficient A ₀ of the quadratic and linear terms. , A ₁ is updated. This changes the shape of the quadratic curve that approximates the running resistance RL from a solid line to a dashed-dotted line. Therefore, updating the coefficients A ₀ and A ₁ of the quadratic and first-order terms is suitable when the air resistance of electric vehicle 100 changes due to installation or replacement of aftermarket parts.

FIG. 12 is a flowchart showing the operation related to updating the coefficients A ₀ , A ₁ , and A ₂ of the approximate expression used to calculate the running resistance RL. As shown in FIG. 12, in step S30, the flat road determination unit 311 determines whether the electric vehicle 100 is traveling on a flat road based on the road surface slope _φLS . If it is determined that the electric vehicle 100 is traveling on a flat road, the process proceeds to step S31, and the steady running determining unit 312 determines that the electric vehicle 100 is traveling steadily without accelerating or decelerating. Determine whether or not there is. If it is determined that the electric vehicle 100 is traveling steadily, the process advances to step S32.

In step S32, the first error calculation unit 313 calculates the first error G _err based on the estimated acceleration G _est and the actual acceleration G _act , and also calculates the duration during which the first error G _err is a significant error. Count τ _err . Then, in step S33, if the duration time τ _err becomes equal to or greater than the threshold value τ ₀ , the process further advances to step S34, where the running resistance storage unit 314 sets the total driving force TQ at that time as the actual running resistance RL _act , and sets the vehicle speed It is stored in association with the VSP.

Then, in step S35, when the number of actual running resistances RL _act becomes three or more, in step S36, the second error calculation unit 315 calculates the second error RL _err and evaluates its dispersion.

After that, in step S37, the coefficient update unit 316 determines whether the variation in the second error RL _err is less than or equal to the threshold TH _err2 . Then, when the variation in the second error RL _err is equal to or less than the threshold value TH _err2 , the process proceeds to step S38, and the coefficient updating unit 316 updates the coefficient A ₂ of the constant term in the approximate expression used to calculate the running resistance RL. On the other hand, when the variation in the second error RL _err is larger than the threshold TH _err2 , the process proceeds to step S39, and the coefficient updating unit 316 updates the coefficient A ₀ of the quadratic and first-order terms in the approximate equation used to calculate the running resistance RL, Update _A1 .

As described above, by updating the coefficients A ₀ , A ₁ , and A ₂ in the approximate expression used to calculate the running resistance RL, even if the running resistance RL changes depending on the specific usage state of the electric vehicle 100. , estimated acceleration G _est and estimated jerk J _est are calculated accurately. As a result, the attitude control execution determination using the estimated acceleration G _est and/or the estimated jerk J _est is accurately performed before the actual pitch angle θ _P and its fluctuation occur. Therefore, attitude control is started in a timely manner without delay in the occurrence of the actual pitch angle θ _P and its fluctuation.

Note that the third embodiment described above can be implemented in combination with either the first embodiment or the second embodiment. Further, in the third embodiment, the first error calculation unit 313 calculates the first error G _err representing the estimation error of the acceleration G, but the first error calculation unit 313 is not limited to this. The first error (J _err ) representing the estimation error of the jerk J can be calculated in a similar manner. In this case, the subsequent processing can be performed in the same manner as in the third embodiment using the first error (J _err ) representing the jerk J estimation error. Further, the first error calculation unit 313 can calculate both the error (G _err ) representing the estimation error of acceleration G and the error (J _err ) representing the estimation error of jerk J as the first error. In this case, the subsequent processing can be performed using both the error (G _err ) representing the estimation error of the acceleration G and the error (J _err ) representing the estimation error of the jerk J. For example, when the error (G _err ) representing the estimation error of the acceleration G continues to be equal to or greater than the threshold value τ ₀ , and/or the error (J _err ) representing the estimation error of the jerk J continues to be equal to or greater than the threshold value τ ₀ , the running resistance The storage unit 314 can be configured to store the actual running resistance RL _act .

Note that in the first embodiment, the second embodiment, and the third embodiment, the attitude control execution determination is performed using both the estimated acceleration G _est and the estimated jerk J _est _. Alternatively, only one of the estimated jerk J _est may be used to determine whether to perform attitude control. Similarly, in the second embodiment, the attitude control execution determination is performed using both the actual acceleration G _act and the actual jerk J _act , but only one of the actual acceleration G _act and the actual jerk J _act It may be used for control execution determination. This also applies when the third embodiment is combined with the second embodiment.

Further, in the first embodiment, the second embodiment, and the third embodiment, the correction unit 48 performs attitude control using feedforward control, but the present invention is not limited to this. Even when posture control is performed by feedback control that feeds back the pitch angle θ _P or pitch rate Δ _P that actually occurred, as in the first embodiment, second embodiment, and third embodiment, It is preferable to perform attitude control execution determination using feedforward control.

As described above, the electric vehicle control methods according to the first embodiment, the second embodiment, and the third embodiment adjust the driving force distribution between the front wheels 21 and the rear wheels 26, which are the driving wheels. This is a control method for electric vehicle 100 that executes attitude control to control the attitude in the longitudinal direction. In this control method for electric vehicle 100, total driving force TQ, which is the required driving force for electric vehicle 100, is calculated based on the operation of the accelerator pedal, and based on total driving force TQ, electric vehicle 100 is controlled by total driving force TQ. An estimated acceleration G _est that is an estimated value for the acceleration G that occurs when driving with , or an estimated jerk J _est that is an estimated value for the jerk J that is the time change rate of the acceleration G is calculated. Then, based on the estimated acceleration G _est or the estimated jerk J _est , an attitude control execution determination is made to turn on/off the attitude control.

In this way, if the attitude control is turned on or off by feedforward control based on the estimated acceleration G _est or estimated jerk J _est , the pitch angle θ _P Attitude control can be started without delay before this change actually occurs. That is, when turning on/off attitude control based on adjustment of driving force distribution as necessary, the delay in determining the start of attitude control can be reduced and attitude control can be implemented in a timely manner. In particular, when the attitude control is performed by feedforward control, the attitude control functions before the pitch angle θ _P and its fluctuation actually occur. Furthermore, even when attitude control is performed by feedback control, control delays caused in attitude control execution determination are reduced. Therefore, the delay in starting attitude control can be minimized. Therefore, as described above, if attitude control is determined to be on/off by feedforward control based on estimated acceleration G _est or estimated jerk J _est , attitude control by adjusting driving force distribution can be performed while suppressing deterioration of electricity consumption. can do. That is, the deterioration in electricity consumption due to attitude control is minimized, and the ride comfort of electric vehicle 100 is improved.

In the electric vehicle control method according to the first embodiment, the second embodiment, and the third embodiment, the estimated acceleration G _est and the estimated jerk J _est are calculated based on the total driving force TQ, and the estimated Posture control is switched on/off based on the acceleration G _est and the estimated jerk J _est . In this way, by using both the estimated acceleration G _est and the estimated jerk J _est for the attitude control execution determination, the accuracy of the attitude control execution determination is improved. Further, attitude control can be turned on at an appropriate timing according to the pitch state (θ _P , Δ _P ) that can be felt by the occupant.

In the electric vehicle control method according to the first embodiment, the second embodiment, and the third embodiment, the estimated acceleration G _est is an acceleration threshold (TH _G ) that is a predetermined threshold value predetermined for the acceleration G. When the above is true and the estimated jerk J _est is equal to or greater than the jerk threshold (TH _J ), which is a predetermined threshold for the jerk J, posture control is turned on. Even with such a simple method, attitude control can be turned on at an appropriate timing according to the pitch state (θ _P , Δ _P ) that can be felt by the occupant.

In the electric vehicle control methods according to the first embodiment, the second embodiment, and the third embodiment, attitude control is performed particularly by feedforward control that corrects driving force distribution based on a vehicle model. In this way, when attitude control is executed by feedforward control, controlling on/off of attitude control based on the attitude control execution determination of feedforward control based on the estimated acceleration G _est or the estimated jerk J _est is particularly effective. , the attitude control functions before the pitch angle θ _P and its variations actually occur. In other words, it is particularly easy to achieve both suppression of deterioration in electricity consumption and improvement of ride comfort through posture control.

In the electric vehicle control methods according to the first embodiment, the second embodiment, and the third embodiment, the slope (φ _LS ) of the road surface on which the electric vehicle 100 runs is acquired, and the slope (φ _LS ) and Attitude control is switched on/off based on the estimated acceleration G _est or the estimated jerk J _est . In this way, according to the posture control execution determination that further takes into account the road surface gradient φ _LS , posture control can be kept off in a driving scene on a sloped road surface where it is difficult for the occupant to experience the pitch angle θ _P and its fluctuations. As a result, deterioration in electricity consumption due to execution of unnecessary attitude control can be suppressed.

Specifically, in the electric vehicle control method according to the first embodiment, the second embodiment, and the third embodiment, when the gradient (φ _LS ) is equal to or less than a predetermined gradient (TH _LS ), the estimated Based on the acceleration G _est or the estimated jerk J _est , it is determined whether attitude control is necessary, and if the gradient (φ _LS ) is larger than the predetermined gradient (TH _LS ), the attitude control is turned off. That is, when the vehicle is traveling on a steeply sloped road surface where it is difficult for the occupant to experience the pitch angle θ _P and its fluctuations, it is possible to maintain the attitude control off particularly reliably. Therefore, deterioration in electricity consumption due to execution of unnecessary posture control is particularly likely to be suppressed.

In the electric vehicle control method according to the second embodiment, the actual acceleration G act is the actual acceleration G generated in the electric vehicle 100, or the actual acceleration G _act is the time change rate of the actual acceleration G generated in the electric vehicle 100. A jerk J _act is obtained. Then, when it is determined that attitude control is necessary based on either the judgment based on the estimated acceleration G _est or the estimated jerk J _est , or the judgment based on the actual acceleration G _act or actual jerk J _act , the attitude control is performed. turned on. In this way, when the determination based on the actual acceleration G _act or the actual jerk J _act is combined, the running resistance RL includes a significant error depending on the specific usage situation of the electric vehicle 100, and the estimated acceleration G _est or the estimated jerk Even if the determination by J _est becomes inaccurate, attitude control is executed when the pitch angle θ _P actually occurs or its fluctuation occurs. That is, if the pitch angle θ _P and its fluctuation actually occur, attitude control will function reliably.

In the electric vehicle control methods according to the first embodiment, the second embodiment, and the third embodiment, the running resistance RL of the electric vehicle 100 is calculated based on the vehicle speed VSP, and the running resistance RL of the electric vehicle 100 is calculated based on the total driving force TQ and the running resistance. Based on RL, estimated acceleration G _est or estimated jerk J _{est is} calculated. In this way, by calculating the estimated acceleration G _est or the estimated jerk J _est based on the running resistance RL, it is possible to accurately calculate the estimated acceleration G _est or the estimated jerk J _est before the acceleration G actually occurs. As a result, the accuracy of attitude control execution determination is improved.

In particular, in the electric vehicle control method according to the third embodiment, it is determined whether the road surface on which the electric vehicle 100 is traveling is a flat road, and whether the electric vehicle 100 is traveling steadily without accelerating or decelerating. It is determined whether or not. Further, the total driving force TQ when the electric vehicle 100 is steadily traveling on a flat road is stored as the actual traveling resistance RL _act , which is the actual traveling resistance. Based on the actual running resistance RL _act , the coefficients A ₀ , A ₁ , and A ₂ used for calculating the running resistance RL are updated. In this way, by updating the coefficients A ₀ , A ₁ , and A ₂ used to calculate the running resistance RL, even if the running resistance RL changes depending on the specific usage state of the electric vehicle 100, the running resistance RL can be updated. Can be calculated accurately. As a result, the accuracy of attitude control execution determination is particularly improved.

Further, in the electric vehicle control method according to the third embodiment, when the electric vehicle 100 is traveling steadily on a flat road, the estimated acceleration G _est and the actual acceleration G that is generated in the electric vehicle 100 are calculated. An acceleration estimation error (G _err ), which is an error between the acceleration G _act and the acceleration G act, is calculated. Then, it is used to calculate the running resistance RL based on the actual running resistance RL _act when the acceleration estimation error (G _err ) greater than or equal to a predetermined error (±G ₀ ) continues for a predetermined time (τ ₀ ) or more. Coefficients A ₀ , A ₁ , A ₂ are updated. In this way, when it is certain that the estimated acceleration G _est includes a significant error with respect to the actual acceleration G _act , by updating the coefficients A ₀ , A ₁ , and A ₂ used for calculating the running resistance RL, Unnecessary updating of the coefficients A ₀ , A ₁ , and A ₂ can be suppressed. As a result, the accuracy of the coefficients A ₀ , A ₁ , and A ₂ improves, so the accuracy of attitude control execution determination is particularly easily maintained.

In the electric vehicle control method according to the third embodiment, a running resistance error (RL _err ), which is an error between the calculated running resistance RL and the actual running resistance RL _act , is calculated, and this running resistance error ( RL _err ) is less than or equal to a predetermined threshold TH _err2 , among the coefficients A ₀ , A ₁ , and A ₂ used to calculate the running resistance RL, the coefficient A ₂ that constitutes a constant term is updated. In this way, if the coefficient _A2 is updated when the variation in the running resistance error (second error RL _err ) is less than the threshold value TH _err2 , when the factors of running resistance other than air resistance, such as rolling resistance, change, It is possible to accurately calculate running resistance RL according to the change. As a result, the accuracy of posture control execution determination is particularly likely to be maintained when rolling resistance or the like changes.

Further, in the electric vehicle control method according to the third embodiment, a running resistance error (RL _err ), which is an error between the calculated running resistance RL and the actual running resistance RL _act , is calculated, and the running resistance error (RL err ) is calculated. _err ) is larger than a predetermined threshold TH _err2 , among the coefficients A ₀ , A ₁ , and A ₂ used to calculate the running resistance RL, the coefficients A ₀ and A ₁ constituting the term including the vehicle speed VSP are Updated. In this way, if the coefficients A ₀ and A ₁ are updated when the variation in the running resistance error (second error RL _err ) is larger than the threshold value TH _err2 , when the air resistance of the electric vehicle 100 changes, the The corresponding running resistance RL can be calculated accurately. As a result, the accuracy of attitude control execution determination is particularly likely to be maintained when air resistance changes.

The control device for an electric vehicle according to the first embodiment, the second embodiment, and the third embodiment adjusts the driving force distribution of the front wheels 21 and the rear wheels 26, which are the driving wheels, to control the posture in the longitudinal direction. This is a control device (controller 12) for electric vehicle 100 that executes attitude control to control. This control device (controller 12) includes a total driving force calculation unit 41 that calculates a total driving force TQ that is a required driving force for the electric vehicle 100 based on the operation of the accelerator pedal, and a total driving force calculation unit 41 that calculates the total driving force TQ that is the required driving force for the electric vehicle 100, and The estimated acceleration G _{est is} an estimated value of the acceleration G that occurs when the vehicle 100 is driven with the total driving force TQ, or the estimated jerk J _{est is} an estimated value of the jerk J that is the time rate of change of the acceleration G. It includes an estimation unit (52, 53) that performs calculations, and an attitude control execution determination unit 47 that makes an attitude control execution determination for switching on/off of attitude control based on the estimated acceleration G _est or the estimated jerk J _est . With this configuration, even if attitude control is turned off due to electricity consumption or the like, attitude control can be started without delay before the pitch angle θ _P and its fluctuation actually occur. Therefore, it is possible to perform attitude control by adjusting the driving force distribution while suppressing deterioration in electricity consumption. That is, the deterioration in electricity consumption due to attitude control is minimized, and the ride comfort of electric vehicle 100 is improved.

Note that the control program for the electric vehicle 100 according to the first embodiment, the second embodiment, and the third embodiment controls the control device (controller 12) of the electric vehicle 100 to Total driving force calculation unit 41 that calculates total driving force TQ that is the required driving force for vehicle 100; Based on total driving force TQ, estimated value of acceleration G that occurs when electric vehicle 100 is driven with total driving force TQ. Estimating unit (52, 53) that calculates the estimated acceleration G _est which is the estimated acceleration G est or the estimated jerk J _{est which} is the estimated value of the jerk J which is the time rate of change of the acceleration G; the estimated acceleration G _est or the estimated jerk J _est It functions as an attitude control execution determination unit 47 that makes an attitude control execution determination for switching on/off of attitude control based on the following.

Although the embodiments of the present invention have been described above, the configurations described in the above embodiments and each modification example merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention. do not have.

Claims

A control method for an electric vehicle that executes attitude control to control the attitude in the longitudinal direction by adjusting the driving force distribution of front wheels and rear wheels that are drive wheels, the method comprising:
Calculating the total driving force that is the required driving force for the electric vehicle based on the operation of the accelerator pedal,
Based on the total driving force, an estimated acceleration that is an estimated value of the acceleration that occurs when the electric vehicle is driven with the total driving force, or an estimated value that is an estimated value of jerk that is a time rate of change of the acceleration. jerk, calculate
making an attitude control execution determination for switching on/off of the attitude control based on the estimated acceleration or the estimated jerk;
How to control electric vehicles.
A method for controlling an electric vehicle according to claim 1,
calculating the estimated acceleration and the estimated jerk based on the total driving force;
switching on/off of the attitude control based on the estimated acceleration and the estimated jerk;
How to control electric vehicles.
A method for controlling an electric vehicle according to claim 2, comprising:
The attitude control is performed when the estimated acceleration is greater than or equal to an acceleration threshold that is a predetermined threshold for the acceleration, and the estimated jerk is greater than or equal to a jerk threshold that is a predetermined threshold for the jerk. turn on,
How to control electric vehicles.
A method for controlling an electric vehicle according to claim 1,
Executing the attitude control by feedforward control that corrects the driving force distribution based on a vehicle model;
How to control electric vehicles.
A method for controlling an electric vehicle according to claim 1,
Obtaining the slope of the road surface on which the electric vehicle runs,
switching on/off of the attitude control based on the gradient and the estimated acceleration or the estimated jerk;
How to control electric vehicles.
The method for controlling an electric vehicle according to claim 5,
If the slope is less than or equal to a predetermined slope, determining whether or not the attitude control is necessary based on the estimated acceleration or the estimated jerk;
if the gradient is larger than the predetermined gradient, turning off the attitude control;
How to control electric vehicles.
A method for controlling an electric vehicle according to claim 1,
Obtaining an actual acceleration that is the actual acceleration that occurred in the electric vehicle, or an actual jerk that is a time change rate of the actual acceleration that occurred in the electric vehicle,
turning on the attitude control when it is determined that the attitude control is necessary based on either the judgment based on the estimated acceleration or the estimated jerk, or the judgment based on the actual acceleration or the actual jerk;
How to control electric vehicles.
A method for controlling an electric vehicle according to claim 1,
Calculating the running resistance of the electric vehicle based on the vehicle speed,
calculating the estimated acceleration or the estimated jerk based on the total driving force and the running resistance;
How to control electric vehicles.
The method for controlling an electric vehicle according to claim 8,
Determining whether the road surface on which the electric vehicle travels is a flat road,
Determining whether the electric vehicle is traveling steadily without accelerating or decelerating;
storing the total driving force when the electric vehicle is steadily traveling on the flat road as an actual running resistance that is the actual running resistance;
updating a coefficient used to calculate the running resistance based on the actual running resistance;
How to control electric vehicles.
The method for controlling an electric vehicle according to claim 9,
when the electric vehicle is traveling steadily on the flat road, calculating an acceleration estimation error that is an error between the estimated acceleration and the actual acceleration that is the actual acceleration that occurs in the electric vehicle;
updating a coefficient used to calculate the running resistance based on the actual running resistance when the acceleration estimation error that is greater than a predetermined error continues for a predetermined time or more;
How to control electric vehicles.
The method for controlling an electric vehicle according to claim 10,
Calculating a running resistance error that is an error between the calculated running resistance and the actual running resistance,
updating a coefficient constituting a constant term among the coefficients used to calculate the running resistance when the variation in the running resistance error is below a predetermined threshold;
How to control electric vehicles.
The method for controlling an electric vehicle according to claim 10,
Calculating a running resistance error that is an error between the calculated running resistance and the actual running resistance,
When the variation in the running resistance error is larger than a predetermined threshold, updating a coefficient constituting a term including the vehicle speed among the coefficients used to calculate the running resistance;
How to control electric vehicles.
A control device for an electric vehicle that performs attitude control to control the attitude in the longitudinal direction by adjusting the driving force distribution of front wheels and rear wheels that are drive wheels, the control device comprising:
a total driving force calculation unit that calculates a total driving force that is a required driving force for the electric vehicle based on the operation of an accelerator pedal;
Based on the total driving force, an estimated acceleration that is an estimated value of the acceleration that occurs when the electric vehicle is driven with the total driving force, or an estimated value that is an estimated value of jerk that is a time rate of change of the acceleration. an estimator that calculates jerk;
an attitude control execution determination unit that makes an attitude control execution determination for switching on/off of the attitude control based on the estimated acceleration or the estimated jerk;
A control device for an electric vehicle, comprising: