WO2024079829A1 - Method for controlling electric vehicle and device for controlling electric vehicle - Google Patents

Abstract

One aspect of the present invention is a method for controlling an electric vehicle, the method adjusting a driving force distribution between front wheels and rear wheels, which are drive wheels, to control the posture of a vehicle body in a front-rear direction. This method for controlling the electric vehicle receives a selection of one seat of a plurality of seats and sets a reference position corresponding to the selected seat. After that, a rotation center of the vehicle body is moved to the reference position by adjusting the driving force distribution.

Description

Control method for electric vehicle and control device for electric vehicle

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

JP2017-71370A discloses an occupant posture control device for a vehicle that, when the vehicle has a seat that can change the support state for the body of a seated occupant, predicts acceleration in the longitudinal direction and width direction of the vehicle based on the vehicle's driving plan, and changes the support state of the occupant's body by the seat in accordance with the predicted acceleration, thereby suppressing the occurrence of car sickness for an occupant seated in the seat.

Vehicle shaking caused by acceleration and deceleration can cause car sickness in passengers. In recent years, it has become clear that the movement of the passenger's head is the main cause of car sickness. Therefore, in order to prevent car sickness, it is necessary to reduce the movement of the passenger's head.

In particular, reducing body movement indirectly reduces head movement, but because the head can move relative to the body, simply reducing body movement does not adequately suppress car sickness. For this reason, in order to more reliably suppress car sickness, it is desirable to more directly reduce head movement, regardless of whether or not body movement is reduced.

The present invention aims to provide a method for controlling an electric vehicle that can directly reduce head movement of occupants and suppress car sickness, and a control device for the electric vehicle.

One aspect of the present invention is a method for controlling an electric vehicle that controls the posture of the vehicle body in the longitudinal direction by adjusting the distribution of driving force between the front and rear wheels, which are the driving wheels. In this method for controlling an electric vehicle, the selection of one of a number of seats is accepted, and a reference position is set according to the selected seat. Then, the center of rotation of the vehicle body is moved to the reference position by adjusting the distribution of driving force.

FIG. 1 is an explanatory diagram showing a schematic configuration of an electric vehicle. FIG. 2 is an explanatory diagram showing a schematic configuration of a chassis system. FIG. 3 is an explanatory diagram showing the center of rotation of the vehicle body and its change. FIG. 4 is an explanatory diagram showing a reference position that is set for the center of rotation in head movement suppression control. FIG. 5 is an explanatory diagram showing the relationship between the position of the rotation center and the direction and amount of movement of the occupant's head. FIG. 6 is a block diagram showing the configuration of a controller for attitude control. FIG. 7 is a block diagram showing the configuration of the attitude control calculation unit. FIG. 8 is an explanatory diagram showing the correction position. FIG. 9 is a flowchart relating to the head movement suppression control. FIG. 10 is a graph that shows a schematic diagram of changes in the head position, pitch angle, and torque of a subject occupant. FIG. 11 is an explanatory diagram showing the range of movement of the center of rotation when adjustment of the drive force distribution and adjustment of the suspension are performed together. FIG. 12 is a flowchart relating to head movement suppression control when the movement of the center of rotation is assisted by adjusting the suspension. FIG. 13 is a flowchart relating to head movement suppression control in a case where suppression of occurrence and variation of pitch angle is assisted by adjustment of the suspension.

Below, an embodiment of the present invention will be explained 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 car or a hybrid vehicle, and is a vehicle capable of driving or braking one or more drive wheels by an electric motor. In particular, in this embodiment, the electric vehicle 100 is a so-called four-wheel drive (4WD) vehicle, and is capable of controlling (adjusting) the driving force generated in each of the multiple drive wheels. Specifically, as shown in FIG. 1, the 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 wheels 21, which are the first drive wheels. The front-wheel drive system 10 includes a front inverter 22 and a front motor 23.

The front inverter 22 converts DC power output by a battery (not shown) into AC power and supplies it to the front motor 23, thereby driving the front motor 23. In addition, when the front motor 23 rotates along with the front wheels 21, the front inverter 22 converts the regenerative AC power generated by the front motor 23 into DC power and inputs it 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. Torque generated by the front motor 23 is transmitted to the front wheels 21 via a front drive shaft 24, generating a driving force on the front wheels 21 (hereinafter referred to as a front wheel driving force F _{2 F} ).

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

The rear inverter 27 converts the DC power output by the battery into AC power and supplies it to the rear motor 28, thereby driving the rear motor 28. Also, when the rear motor 28 rotates along with the rear wheels 26, the rear inverter 27 converts the regenerative AC power generated by the rear motor 28 into DC power and inputs it 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, for example, configured by a three-phase AC synchronous motor similar to the front motor 23. Torque generated by the rear motor 28 is transmitted to the rear wheels 26 via a rear drive shaft 29, generating a driving force on the rear wheels 26 (hereinafter referred to as rear wheel driving force _FR ).

The controller 12 is composed of one or more computers that control the operation of the electric vehicle 100. The controller 12 is programmed to control the operation of the electric vehicle 100 at a predetermined control period. In this embodiment, the controller 12 is a control device for the electric vehicle 100 that performs posture control to control the posture in the fore-and-aft direction by adjusting the distribution of driving force between the front wheels 21 and the rear wheels 26, which are the driving wheels.

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

When controlling the operation of the electric vehicle 100, the controller 12 can appropriately acquire various parameters that indicate the operating state of the electric vehicle 100 by a sensor (not shown) or by calculation. For example, the electric vehicle 100 is equipped with an accelerator opening sensor (not shown) that detects an accelerator opening _APO . Therefore, the controller 12 can appropriately acquire the accelerator opening _APO . The accelerator opening _APO is a parameter that indicates the amount of operation of the accelerator pedal. In addition, the controller 12 appropriately acquires the vehicle speed VSP of the electric vehicle 100 by a sensor (not shown) or by calculation.

In addition, in this embodiment, the electric vehicle 100 is equipped with a seat selector 13 and an object detector 14.

The seat selector 13 is a user interface that accepts the selection of one of the multiple seats that the electric vehicle 100 has. The seat selector 13 is configured, for example, by a mechanical switch or a selection menu displayed on a screen. The seat selector 13 is used by the driver or other passengers to select a seat in which a passenger who may suffer from car sickness is located.

The seat selector 13 is selected by the driver or the like, and inputs a signal or setting information indicating a seat (hereinafter referred to as a target seat S- _S ) in which a passenger who is a target for suppressing car sickness is located to the controller 12. Therefore, the controller 12 can control the operation of the electric vehicle 100 according to the target seat S- _S . In this embodiment, the controller 12 controls the operation of the electric vehicle 100 in particular so as to directly suppress movement of the head of the passenger in the target seat S- _S . As a result, car sickness of the passenger in the target seat S _-S is suppressed in the electric vehicle 100. With regard to the "movement" of the passenger's head, it is assumed that this refers to shaking or other movement caused by the operation of the electric vehicle 100, such as acceleration or deceleration.

The electric vehicle 100 has seats, for example, a driver's seat, a passenger seat, and one or more rear seats 34 (see FIG. 4). The driver's seat and passenger seat are seats located in the front of the electric vehicle 100 relative to the rear seats 34. In the following description, when there is no particular need to distinguish between them, the driver's seat and passenger seat are collectively referred to as the front seats 33 (see FIG. 4).

The object detector 14 detects an occupant in the target seat S _S , i.e., a specific occupant (hereinafter referred to as a target occupant) who is a target for suppressing car sickness. The object detector 14 inputs a detection signal or the like (hereinafter referred to as a target detection signal S _D ) for the target occupant to the controller 12. Therefore, by using the target detection signal S _D , the controller 12 can control the operation of the electric vehicle 100 according to the actual movement of the target occupant. In this embodiment, the controller 12 feeds back the actual movement of the head of the target occupant to the operation control of the electric vehicle 100 based on the target detection signal S _D. This allows the movement of the head of the target occupant to be suppressed particularly precisely.

The object detector 14 is, for example, a camera that captures an image of the occupant including all or part of the head, or a sensor that detects the position of the occupant's head relative to each seat, etc. In this embodiment, the object detector 14 is a camera that captures an image of the target occupant, and the object detection signal S _D is an image or video captured of the target occupant.

The seat selector 13 and the object detector 14, together with the controller 12, constitute a control device for the electric vehicle 100.

<Principle of attitude control by 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 to a vehicle upper part (hereinafter referred to as a vehicle body 101) in which a vehicle interior and the like are formed, via a front suspension 31. Similarly, the rear wheels 26 are connected to the vehicle body 101 via a rear suspension 32.

For example, when the electric vehicle 100 is accelerated by the front wheel driving force F _F , the rear wheel driving force F _R , or both, the load moves rearward (negative side in the X direction) of the electric vehicle 100. As a result, a moment acting in a direction that increases the pitch angle θ _P is generated in the vehicle body 101, centered on the center of rotation C. For this reason, when the electric vehicle 100 accelerates, in principle, the electric vehicle 100 assumes a posture in which the front portion, which is the portion on the positive side in the X direction, is lifted up (so-called nose-up posture).

On the other hand, the torque of the front motor 23 (hereinafter referred to as the front torque T _F ) which generates the front wheel driving force F _F acts on the vehicle body 101 via the front suspension 31. Specifically, the front torque T _F generates a moment acting in a direction to reduce the pitch angle θ _P around the virtual center of rotation O _F of the vehicle body 101 by the front wheels 21. That is, when the electric vehicle 100 accelerates, the front torque T _F suppresses the nose-up. Similarly, the torque of the rear motor 28 (hereinafter referred to as the rear torque T _R ) which generates the rear wheel driving force F _R acts on the vehicle body 101 via the rear suspension 32 and generates a moment acting in a direction to reduce the pitch angle θ _P around the virtual center of rotation O _R of the vehicle body 101 by the rear wheels 26. Therefore, when the electric vehicle 100 accelerates, the rear torque T _R suppresses the nose-up.

The magnitude of the effect of the front torque T _F to suppress nose-up during acceleration depends on the magnitude of the anti-scut angle θ _F. Similarly, the magnitude of the effect of the rear torque T _R to suppress nose-up during acceleration depends on the magnitude of the anti-scut angle θ _R. For this reason, if the drive force distribution to the front wheels 21 and the rear wheels 26 is adjusted so that the distribution to the drive wheels having relatively large anti-scut angles is increased, the effect of suppressing nose-up becomes greater while maintaining the total drive force TQ. Therefore, the controller 12 can execute posture control that controls the posture of the electric vehicle 100 in the fore-and-aft direction by adjusting the drive force distribution to the front wheels 21 and the rear wheels 26.

The virtual center of rotation O _F is an instantaneous and virtual center of rotation generated in the vehicle body 101 by the transmission of the front torque T _F , and is determined in advance by the specific configuration of the front suspension 31, etc. Similarly, the virtual center of rotation O _R of the rear part is an instantaneous and virtual center of rotation generated in the vehicle body 101 by the transmission of the rear torque T _R , and is determined in advance by the specific configuration of the rear suspension 32, etc. The center of rotation C is an actual center of rotation of the vehicle body 101 determined by the virtual centers of rotation O _F and O _R determined by the suspension geometry as described above, and the distribution of the front torque T _F and the rear torque T _R. The anti-scat angle θ _F is an angle formed by a line connecting the center of rotation of the front wheel 21 and the virtual center of rotation O _F and a line parallel to the road surface on the XZ plane. Similarly, the anti-scat angle θ _R is an angle formed by a line connecting the center of rotation of the rear wheel 26 and the virtual center of rotation O _R and a line parallel to the road surface on the XZ plane.

FIG. 3 is an explanatory diagram showing the rotation center C of the vehicle body 101 and its change. As shown in FIG. 3, the rotation center C when the driving force distribution between the front wheels 21 and the rear wheels 26 is in a standard state (for example, a state in which the front wheel driving force F _F : the rear wheel driving force F _R = 50:50) that is predetermined according to the electric power consumption, etc., is defined as the rotation center C _STD . When the front wheel driving force F _F increases, the rotation center C of the vehicle body 101 moves from the position of the rotation center C _STD in the standard state to the front of the electric vehicle 100. When the total driving force TQ is generated only by the front wheels 21, that is, when F _F : F _R = 100:0, the rotation center C of the vehicle body 101 reaches the foremost rotation center C _100:0 . On the other hand, when the rear wheel driving force F _R increases, the rotation center C of the vehicle body 101 moves from the position of the rotation center C _STD in the standard state to the rear of the electric vehicle 100. When the total driving force TQ is generated only by the rear wheels 26, that is, when F _F :F _R = 0:100, the center of rotation C of the body 101 reaches the rearmost center of rotation C _0:100 . Therefore, in the electric vehicle 100, the center of rotation C of the body 101 can be adjusted within a range from the foremost center of rotation C _100:0 to the rearmost center of rotation C _0:100 by distributing the driving force between the front wheels 21 and the rear wheels 26.

In this embodiment, the controller 12 selectively executes two different types of attitude control by distributing the driving force between the front wheels 21 and the rear wheels 26 as described above. The first attitude control is "pitch angle suppression control." The second attitude control is "head movement suppression control."

<Pitch angle suppression control>
In the pitch angle suppression control, the vehicle body 101 is the target for controlling the attitude. That is, in the pitch angle suppression control, the occurrence and variation of the pitch angle θ _P are suppressed. More specifically, the pitch angle suppression control is a posture control that makes the attitude of the vehicle body 101 approach a predetermined target posture and maintains it. In this embodiment, the anti-squat angle θ _R of the rear suspension 32 is larger than the anti-squat angle θ _F of the front suspension 31 (see FIG. 2). For this reason, when the increase of the pitch angle θ _P is suppressed or reduced during acceleration, for example, by the pitch angle suppression control, the controller 12 relatively increases the drive force distribution to the rear wheels 26.

Here, we have explained the relationship between the configuration of the chassis system and the pitch angle suppression control during acceleration, but even during deceleration, the controller 12 executes pitch angle suppression control by adjusting the drive force distribution to the front wheels 21 and the rear wheels 26. However, during deceleration, the electric vehicle 100 assumes a posture in which the front part sinks (a so-called nose dive posture), which is the opposite of the above, and the controller 12 adjusts the drive force distribution to the front wheels 21 and the rear wheels 26 accordingly.

<Head movement suppression control>
In the head movement suppression control, the head of the target occupant in the target seat S _S is the target for controlling the posture. That is, in the head movement suppression control, the movement of the head of the target occupant is suppressed, and as a result, car sickness of the target occupant is suppressed. More specifically, the head movement suppression control is posture control that moves the center of rotation C of the vehicle body 101 so as to suppress the movement of the head of the target occupant. For this reason, the head movement suppression control may increase the fluctuation of the pitch angle _θP caused by the acceleration or deceleration of the electric vehicle 100.

Fig. 4 is an explanatory diagram showing a reference position ( _Cα or _Cβ ) set for the center of rotation C in head movement suppression. As shown in Fig. 4, in this embodiment, it is assumed that an occupant _P1 is seated in the front seat 33, and an occupant _P2 is seated in the rear seat 34. When the occupant _P1 is seated in the front seat 33, the head _H1 of the occupant _P1 is generally located at a position _L1 in the front-rear direction of the electric vehicle 100. Similarly, when the occupant _P2 is seated in the rear seat 34, the head _H2 of the occupant _P2 is generally located at a position _L2 in the front-rear direction of the electric vehicle 100. That is, the positions of the heads _H1 , _H2 of the occupants _P1 , _P2 are generally determined by sitting in the seats.

Therefore, when executing head movement suppression control, the controller 12 sets a rough reference position (hereinafter referred to as the reference position) for the position to which the center of rotation C should be moved by adjusting the distribution of driving force between the front wheels 21 and the rear wheels 26 in accordance with the selection of the target seat S _S.

When the front seat 33 is selected as the target seat S _S , the controller 12 sets the position L ₁ where the head H ₁ of the occupant P ₁ seated in the front seat 33 is located as the reference position. Then, the controller 12 adjusts the distribution of driving force to the front wheels 21 and the rear wheels 26 so that the center of rotation C of the vehicle body 101 moves from the standard center of rotation C _STD to the center of rotation C _α on the position L ₁ set as the reference position. Similarly, when the rear seat 34 is selected as the target seat S _S , the controller 12 sets the reference position to the position L ₂ where the head H ₂ of the occupant P ₂ seated in the rear seat 34 is located. Then, the controller 12 adjusts the distribution of driving force to the front wheels 21 and the rear wheels 26 so that the center of rotation C of the vehicle body 101 moves from the standard center of rotation C _STD to the center of rotation C _β on the position L ₂ set as the reference position.

The center of rotation C of the vehicle body 101 is normally located below (in the direction toward the road surface) the heads _H1 , _H2 of the occupants _P1 , _P2 , and moves in the front-to-rear direction depending on the distribution of driving force between the front wheels 21 and the rear wheels 26. For this reason, when position _L1 is taken as the reference position, the center of rotation _Cα after adjustment by the head movement suppression control does not coincide with the head _H1 of the occupant _P1 , but is located around the body _B1 . Similarly, when position _L2 is taken as the reference position, the center of rotation _Cβ after adjustment does not coincide with the head _H2 of the occupant _P2 , but is located around the body _B2 .

5 is an explanatory diagram showing the relationship between the position of the rotation center C and the direction and amount of movement of the head _H1 of the occupant _P1 . As shown in Fig. 5, the occupant _P1 in the front seat 33 is the target occupant, and the head movement suppression control is used to move the rotation center C of the vehicle body 101 from the standard rotation center C _STD to the rotation center _Cα on the position _L1 .

When the center of rotation C of the vehicle body 101 is at the standard center of rotation C _STD , if the vehicle body 101 rotates at a pitch angle θ _P , the head H ₁ of the occupant P ₁ moves along an arc centered on the standard center of rotation C _STD . Therefore, the amount of movement of the head H ₁ when the center of rotation C of the vehicle body 101 is at the standard center of rotation C _STD can be roughly calculated using the pitch angle θ _P and the distance r _STD from the standard center of rotation C _STD to the head H ₁ , and is approximately r _STD · θ _P.

Similarly, when the center of rotation C of the vehicle body 101 moves to the center of rotation _Cα on the position _L1 and the vehicle body 101 rotates at a pitch angle _θP , the head H1 of the occupant P1 moves along an arc centered on the center of rotation _Cα after the movement. Therefore, the amount of movement of the head _H1 when the center of rotation C of the vehicle body 101 is at the center of rotation _Cα after the movement due to the head movement suppression control can be roughly calculated using the pitch angle _θP and the distance _rα from the center of rotation _Cα to the head _H1 , and is approximately _rα · _θP .

Then, the distance r _α from the center of rotation C _α to the head H ₁ after the movement is shorter than the distance r _STD from the standard center of rotation C _STD to the head H ₁ .

Therefore, when a rotation that generates a certain pitch angle _θP occurs in the vehicle body 101, the center of rotation C of the vehicle body ₁₀₁ is moved to the reference position ( _L1 ) or a center of rotation ( _Cα ) nearby the reference position ( _L1 ) by the head movement suppression control, and is maintained at the reference position (L1) or nearby, thereby reducing the amount of movement of the head H1. As a result, the occurrence or onset of car sickness in the occupant _P1 is suppressed.

When the center of rotation C of the vehicle body 101 is at the standard center of rotation C _STD , the direction of movement of the head _H1 is inclined with respect to a direction parallel to the road surface (here, the horizontal direction). In contrast, when the center of rotation C of the vehicle body 101 is moved to the center of rotation (C _α ) of the standard position (L ₁ ) by the head movement suppression control, the direction of movement of the head _H1 becomes approximately parallel to the road surface (horizontal direction).

The reference position may be set by a range, not a pinpoint. For example, when the target seat S _S is the front seat 33, a point that coincides with the position L ₁ or a predetermined range including the position L ₁ may be set as the reference position. The predetermined range including the position L ₁ is determined in advance by an experiment, a simulation, or the like. This is also true when the target seat S _S is the rear seat 34. That is, when the target seat S _S is the rear seat 34, a point that coincides with the position L ₂ or a predetermined range including the position L ₂ may be set as the reference position. Therefore, in this embodiment, moving the rotation center C to the reference position means moving the rotation center _C closer to the positions L ₁ and L ₂ where the heads H ₁ and H ₂ are located so that the amount of movement of the heads H ₁ and H ₂ when the pitch angle θ P occurs is substantially reduced.

<Configuration for attitude control>
Fig. 6 is a block diagram showing the configuration of the controller 12 for posture control. As shown in Fig. 6, the controller 12 includes a total driving force calculation unit 41, a basic distribution calculation unit 42, a posture control calculation unit 43, a head movement detection unit 44, a driving force setting unit 45, a front motor control unit 46, and a rear motor control unit 47.

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

Incidentally, instead of calculating the total driving force TQ based on the accelerator pedal opening _APO as described above, the total driving force calculation unit 41 can calculate the total driving force TQ based on commands from an ADAS (Advanced Drive Assistance System) or an AD (Autonomous Driving) system, etc. These systems are systems that substitute for the operation of the accelerator pedal by the driver, so the calculation of the total driving force TQ that the total driving force calculation unit 41 performs based on commands from these systems is substantially a calculation based on the operation of the accelerator pedal.

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

In this embodiment, the basic distribution calculation unit 42 calculates a first front torque target value T _F1 ^* and a 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 ^* is a target value for the front motor torque that generates a front wheel driving force F _F corresponding to the basic distribution at the front wheels 21. The first rear torque target value T _R1 ^* is a target value for the rear torque that generates a rear wheel driving force F _R corresponding to the basic distribution at the rear wheels 26. Hereinafter, the combination of the first front torque target value T _F1 ^* and the first rear torque target value T _R1 ^* is referred to as the basic driving force distribution (T _F1 ^* , T _R1 ^* ).

The attitude control calculation unit 43 calculates a corrected driving force distribution (T _F2 ^* , T _R2 ^* ), which is a driving force distribution for controlling the attitude of the electric vehicle 100. The corrected driving force distribution (T _F2 ^* , T _R2 ^* ) is a combination of a final front torque target value (hereinafter referred to as a second front torque target _value T _F2 ^* ) and a rear torque target value (hereinafter referred to as a second rear torque target value T _R2 ^* ) for controlling the attitude of the electric vehicle 100, i.e., the pitch angle θ P of the vehicle body 101.

When the target seat S _S is not selected, the posture control calculation unit 43 calculates a corrective driving force distribution (T _F2 ^* , T _R2 ^* ) that suppresses the occurrence or variation of the pitch angle θ _P. In other words, when the target seat S _S is not selected and there is no occupant who is prone to car sickness, the posture control calculation unit 43 calculates a corrective driving force distribution (T _F2 ^* , T _R2 ^* ) that realizes pitch angle suppression control.

On the other hand, when the target seat S _S is selected, the posture control calculation unit 43 calculates a corrected driving force distribution (T _F2 ^* , T _R2 ^* ) that suppresses head movement of the target occupant seated in the target seat S _S. That is, when the target seat S _S is selected and there is an occupant who is prone to car sickness, the posture control calculation unit 43 calculates a corrected driving force distribution (T _F2 ^* , T _R2 *) that realizes head movement suppression control for the target occupant. Therefore, the corrected driving force distribution (T _F2 ^* , T _R2 ^{* )} for controlling the posture of the electric vehicle 100 has a different effect on the electric vehicle 100 depending on whether pitch angle suppression control is executed or head movement suppression control is executed.

Furthermore, when calculating the corrected driving force distribution (T _F2 ^* , T _R2 ^* ) that realizes head movement suppression control, the posture control calculation unit 43 calculates the corrected driving force distribution (T _F2 ^* , T _R2 *) based on at least the selection of the target seat S _S. In particular, in this embodiment, when calculating the corrected driving force distribution (T _F2 ^* , T _R2 ^{* )} that realizes head movement suppression control, the posture control calculation unit 43 obtains detection results regarding the movement of the head of the target occupant from the head movement detection unit 44. Then, the posture control calculation unit 43 calculates the corrected driving force distribution (T _F2 ^* , T _R2 ^* ) based on the target seat S _S and the detection results regarding the movement of the head of the target occupant.

The head movement detection unit 44 detects head movement of the target occupant in the target seat S _S based on the target detection signal S _D at least when the target seat S _S is selected. Specifically, the head movement detection unit 44 detects the amount of movement and the direction of movement (the direction of the force acting on the head) of the target occupant's head by calculating the position, speed, acceleration, etc., or all or a part of these parameters, for the target occupant's head. The detection result of the movement of the target occupant's head (hereinafter referred to as the head movement detection result) is used by the attitude control calculation unit 43 to calculate the corrected drive force distribution ( _TF2 ^* , _TR2 ^* ) for head movement suppression control, as described above.

In this embodiment, the head movement detection unit 44 detects the position of the head relative to position _L1 or position _L2 depending on the target seat _S as the amount of movement of the target occupant's head. In addition, the head movement detection unit 44 detects the direction of movement of the target occupant's head based on the acceleration of the head.

In addition, in this embodiment, since the target detection signal _SD is an image or video of the target occupant, the head movement detection unit 44 detects the movement of the head of the target occupant by analyzing the image or video.

The driving force setting unit 45 sets the distribution of the driving force generated by the front wheels 21 and the rear wheels 26 to either the basic driving force distribution ( _TF1 ^* , _TR1 ^* ) or the corrected driving force distribution ( _TF2 ^* , _TR2 ^* ). For example, when the posture control is turned on by the settings or the like, or when the execution of the posture control is permitted, the driving force setting unit 45 sets the driving force distribution of the front wheels 21 and the rear wheels 26 to the corrected driving force distribution ( _TF2 ^* , _TR2 ^* ). On the other hand, when the posture control is turned off by the settings or the execution of the posture control is not permitted, the driving force setting unit 45 sets the driving force distribution of the front wheels 21 and the rear wheels 26 to the basic driving force distribution ( _TF1 ^* , _TR1 ^* ). In this embodiment, for simplicity, it is assumed that the posture control is turned on by the settings or the execution of the posture control is permitted. That is, in the following, it is assumed that the driving force setting unit 45 sets the driving force distribution between the front wheels 21 and the rear wheels 26 to the corrected driving force distribution ( _TF2 ^* , _TR2 ^* ).

The driving force setting unit 45 actually adjusts (sets) the driving force distribution to move the center of rotation C of the vehicle body 101. That is, the driving force setting unit 45 is an execution unit of posture control, and when performing pitch angle suppression control, it moves the center of rotation C of the vehicle body 101 in accordance with the generated pitch angle _θP , and when performing head movement suppression control, it moves the center of rotation C of the vehicle body 101 to a reference position.

The front motor control unit 46 controls the front motor 23 via the front inverter 22 so that the driving force set by the driving force setting unit 45 is generated at the front wheels 21. When a first front torque target value T _F1 ^* commanding a basic driving force is input, the front motor control unit 46 causes the front motor 23 to generate a front torque T _F corresponding to the first front torque target value T _F1 ^* . On the other hand, when a second front torque target value T _F2 ^* commanding a corrective driving force for posture control is input, the front motor control unit 46 causes the front motor 23 to generate a front torque T _F corresponding to the second front torque target value T _F2 ^* . As a result, the front wheel driving force F _F is controlled to the basic driving force or the corrective driving force.

The rear motor control unit 47 controls the rear motor 28 via the rear inverter 27 so that the driving force set by the driving force setting unit 45 is generated at the rear wheels 26. When a first rear torque target value _TR1 ^* commanding a basic driving force is input, the rear motor control unit 47 causes the rear motor 28 to generate a rear torque _TR corresponding to the first rear torque target value _TR1 ^* . On the other hand, when a second rear torque target value _TR2 ^* commanding a corrective driving force for posture control is input, the rear motor control unit 47 causes the rear motor 28 to generate a rear torque _TR corresponding to the second rear torque target value _TR2 ^* . As a result, the rear wheel driving force _FR is controlled to the basic driving force or the corrective driving force.

The front motor control unit 46 and the rear motor control unit 47 constitute a driving wheel control unit that controls (drives) the front wheels 21 and the rear wheels 26 in accordance with the basic driving force distribution ( _TF1 ^* , _TR1 ^* ) or the corrected driving force distribution ( _TF2 ^* , _TR2 ^* ).

FIG. 7 is a block diagram showing the configuration of the attitude control calculation unit 43. As shown in FIG. 7, the attitude control calculation unit 43 includes a reference position setting unit 51, a correction position calculation unit 52, and a correction allocation calculation unit 53.

When the target seat S _S is selected, the reference position setting unit 51 sets a reference position in the front-rear direction of the electric vehicle 100 according to the selected target seat S _S. For example, when the front seat 33 is the target seat S _S , the reference position setting unit 51 sets "position L ₁ " where the head H _{1 of the occupant P 1} in the front seat 33 is located, as the reference position. Similarly, when the rear seat 34 is the target seat S _S , the reference position setting unit 51 sets "position L ₂ " where the head H ₂ of the occupant P ₂ in the rear seat 34 is located, as the reference position. Information on the reference position set by the reference position _setting unit 51 is input to the correction position calculation unit 52.

The correction position calculation unit 52 calculates a correction position that moves around the reference position in accordance with the actual movement of the target occupant's head, based on the set reference position and the head movement detection result by the head movement detection unit 44. In other words, the correction position is the target movement position of the rotation center C that has been fine-tuned in accordance with the actual movement of the target occupant's head.

Fig. 8 is an explanatory diagram showing the corrected position. Fig. 8(A) shows the movement of the head of the target occupant when the rotation center C of the vehicle body 101 is maintained at the rotation center on the reference position. Fig. 8(B) shows the movement of the head of the target occupant when the rotation center C of the vehicle body 101 is moved to follow the corrected position with the reference position as the center. In Fig. 8, the reference position is position _L1 , and the target occupant is occupant _P1 .

As shown in Fig. 8(A), when the center of rotation C of the vehicle body 101 is a center of rotation _Cα on position _L1 , when a rotation that generates a pitch angle _θP occurs in the vehicle body 101, the head _H1 of the occupant _P1 moves generally in the front-rear direction, and the amount of movement is approximately _rα · _θP . Here, as shown in Fig. 8(B), if the center of rotation C of the vehicle body 101 is moved in the opposite direction to the movement direction of the head _H1 by a width corresponding to the pitch angle _θP (a range of approximately the amount of head movement ( _rα · _θP )) around position _L1 , which is the reference position, the amount of movement of the head _H1 can be further reduced and maintained at substantially zero.

In this way, when the center of rotation C of the vehicle body 101 is moved about the position _L1 , the center of rotation C when it is at the frontmost position of the electric vehicle 100 is "C _α ⁺ ", and the center of rotation C when it is at the rearmost position is "C _α ^- ". The position of the center of rotation _C at each _time in the process of moving the center of rotation C _α ⁺ at the front end and the center of rotation C _α ^- at the rear end about the center of rotation C _α at the position L1 is the corrected position. Therefore, the corrected position calculated by the corrected position calculation unit 52 is the target position of the center of rotation C corrected by feeding back the movement of the head H1 of the individual occupant _P1 .

The correction distribution calculation unit 53 (see FIG. 7) calculates the corrected driving force distribution (T _F2 ^* , T _R2 ^* ) by redistributing the total driving force TQ or by correcting the basic driving force distribution (T _F1 ^* , T _R1 ^* ).

When the target seat S 2 _S is selected and the correction position calculation unit 52 inputs the correction position to the correction allocation calculation unit 53, the correction allocation calculation unit 53 calculates a correction drive force allocation ( _TF2 ^* , _TR2 ^* ) for head movement suppression control that causes the rotation center C of the vehicle body 101 to follow the correction position. The front motor 23 and the rear motor 28 are driven in accordance with this correction drive force allocation ( _TF2 ^* , _TR2 ^* ) for head movement suppression control, thereby suppressing movement of the head of the target occupant.

On the other hand, when the target seat S 2 _S is not selected and the correction position calculation unit 52 does not input the correction position to the correction allocation calculation unit 53, the correction allocation calculation unit 53 calculates a correction driving force allocation (T _F2 ^* , T _R2 ^* ) for pitch angle suppression control based on, for example, a vehicle model of the electric vehicle 100. The front motor 23 and the rear motor 28 are driven in accordance with this correction driving force allocation (T _F2 ^* , T _R2 ^* ) for pitch angle suppression control, whereby the pitch angle θ _P is controlled to a preset target pitch angle.

It should be noted that the correction position calculation unit 52 may be omitted. In this case, the correction allocation calculation unit 53 acquires the reference position from the reference position setting unit 51, and calculates a correction drive force allocation ( _TF2 ^* , _TR2 ^* ) for head movement suppression control so that the center of rotation C of the vehicle body 101 becomes the reference position. In this embodiment, as described above, the correction position calculation unit 52 calculates the correction position, and calculates a correction drive force allocation ( _TF2 ^* , _TR2 ^* ) for head movement suppression control that causes the center of rotation C of the vehicle body 101 to follow the correction position.

<Action>
Hereinafter, the operation of the head movement suppression control of the electric vehicle 100 configured as above will be described.

9 is a flow chart relating to the head movement suppression control. As shown in FIG. 9, when the seat selector 13 accepts the selection of the target seat S 1 _S in which the target occupant who should be suppressed from car sickness sits in step S10, the reference position setting unit 51 checks in step S11 whether the target seat S _{1 S} is the driver's seat or the passenger seat. In step S11, if the target seat S _{1 S} is the driver's seat or the passenger seat, that is, if the target seat S _{1 S} is the front seat 33, the process proceeds to step S12, where the reference position setting unit 51 sets the reference position to the position L ₁ of the head H ₁ of the occupant P ₁ sitting in the front seat 33. On the other hand, in step S11, if the target seat S _{1 S} is the rear seat 34, the process proceeds to step S13, where the reference position setting unit 51 sets the reference position to the position L ₂ of the head H ₂ of the occupant P ₂ sitting in the rear seat 34.

In step S14, the head movement detection unit 44 detects the movement of the head of the target occupant in the target seat S _S , i.e., the amount and direction of movement of the head of the target occupant. Then, in step S15, the corrected position calculation unit 52 calculates a corrected position based on the reference position and the head movement detection result by the head movement detection unit 44.

In step S16, the correction distribution calculation unit 53 calculates a corrected driving force distribution ( _{TF2*, TR2*) for head movement suppression control that causes the center of rotation C of the vehicle body 101 to follow the corrected position. Then, in step S17, the driving force setting unit 45 sets the corrected driving force distribution (TF2} ^* _{, TR2} ^* ₎ ^{for head} _{movement suppression control, and the front wheels 21 and rear wheels 26 are driven in accordance with the corrected driving force distribution (TF2 *} ^, _TR2 ^* ).

Fig. 10 is a graph showing a schematic transition of the head position _XH , pitch angle _θP , and torques T _F and T _R of a target occupant. Fig. 10 shows an example of a driving scene in which the electric vehicle 100 is stopped and the accelerator is operated at time _t0 to start moving. Figs. 10(A) to 10(C) show parameters in a comparative example in which head movement suppression control is not performed and pitch angle suppression control is continued. Figs. 10(D) to 10(D) show parameters in this embodiment in which head movement suppression control is performed according to this embodiment. Note that the dashed lines in Fig. 10 show parameters in a reference example in which posture control is not performed, i.e., neither head movement suppression control nor pitch angle suppression control is performed.

In the comparative example in which pitch angle suppression control is performed, when the electric vehicle 100 starts moving, the vehicle body 101 turns nose-up and a pitch angle _θP occurs as shown in Fig. 10(B), and the corrective driving force distribution ( _TF2 ^* , _TR2 ^* ) is set so as to suppress the nose-up, thereby adjusting the front torque _TF and the rear torque _TR as shown in Fig. 10(C). As a result, as shown in Fig. 10(B), the pitch angle _θP is reduced more than in the reference example (dashed line) in which attitude control is not performed.

10A, the head of the target occupant moves, for example, back and forth in a vibrational manner and then approaches the reference position (zero position) in response to the fluctuation of the pitch angle θ _P. In addition, the pitch angle suppression control reduces the pitch angle θ _P , and compared to the reference example (broken line) in which no attitude control is performed, the pitch angle suppression control suppresses the movement of the head of the target occupant.

Even when the head movement suppression control of this embodiment is performed, when the electric vehicle 100 starts, the vehicle body 101 still has the nose up and generates the pitch angle _θP , as shown in FIG. 10(E). However, in the head movement suppression control of this embodiment, the center of rotation C of the vehicle body 101 is generally moved to a reference position corresponding to the target seat S _S. Therefore, as shown in FIG. 10(F), the head movement suppression control has a different distribution of driving force between the front wheels 21 and the rear wheels 26 from the pitch angle suppression control. Therefore, as shown in FIG. 10(E), for example, near time _t1 , the pitch angle _θP may be larger than the reference example (broken line) in which the attitude control is not performed. On the other hand, as shown in FIG. 10(D), the movement of the head of the target occupant is reduced compared to the case where the pitch angle suppression control is performed. In particular, if the head position _XH of the target occupant is compared after time _t2 when the front torque T _F and the rear torque T _R converge, the difference is clear. Therefore, according to the head movement suppression control of this embodiment, the movement of the head of the target occupant is suppressed particularly effectively, thereby suppressing car sickness in the target occupant.

Furthermore, in the head movement suppression control of this embodiment, the position to which the rotation center C of the vehicle body 101 is moved is adjusted oscillatorily around the reference position so as to follow the corrected position obtained by feeding back the detection result of the movement of the head of the target occupant. As a result, as shown in FIG. 10(F), the front torque T _F and the rear torque T _R change oscillatorily more than in the case of performing the pitch angle suppression control. In particular, in the vicinity of time t ₁ , as shown in FIG. 10(E), the inclination (pitch angle θ _P ) of the vehicle body 101 in the front-rear direction increases more than in the case of maintaining the rotation center C of the vehicle body 101 at the reference position. As a result, as shown in FIG. 10(D), in the head movement suppression control, the swing back of the head of the target occupant is reduced in the vicinity of time t _1. In comparison with the pitch angle suppression control, in which the head of the target occupant experiences a large swing back in the vicinity of time t ₁ as shown in FIG. 10(A), the swing back reduction effect of the head movement suppression control of this embodiment is clear.

In this way, the head movement suppression control of this embodiment can suppress the movement (particularly the amount of movement) of the target occupant's head more directly and effectively than pitch angle suppression control by moving the center of rotation C of the vehicle body 101 to a reference position. Furthermore, the head movement suppression control of this embodiment can suppress the swing back (vibration) that occurs in the target occupant's head by making the center of rotation C of the vehicle body 101 follow the corrected position. Therefore, the head movement suppression control of this embodiment suppresses car sickness in the target occupant better than ever before.

[Second embodiment]
In the first embodiment, the front suspension 31 and the rear suspension 32 have a predetermined height and damping force. However, when the front suspension 31 and the rear suspension 32 are so-called active suspensions and their heights and damping forces are adjustable, it is preferable to adjust the front suspension 31 and the rear suspension 32 in the head movement suppression control. In the second embodiment described below, the length (height) and damping force of the front suspension 31 and the rear suspension 32 are adjustable, and the front suspension 31 and the rear suspension 32 are adjusted in the head movement suppression control.

FIG. 11 is an explanatory diagram showing the range of movement of the center of rotation C when adjusting the drive force distribution and the suspension at the same time.

For example, if the length (height) of the front suspension 31 or the rear suspension 32 is adjusted to lower the vehicle height at the front of the electric vehicle 100 relative to the vehicle height at the rear, the vehicle body 101 will assume a posture similar to that of a nose dive from the beginning. Therefore, adjusting the suspension to lower the vehicle height at the front of the electric vehicle 100 has substantially the same effect as adjusting the driving force distribution to suppress nose-up. In the electric vehicle 100 of this embodiment, adjusting the suspension to lower the vehicle height at the front of the electric vehicle 100 corresponds to adjusting the driving force distribution to increase the driving force distribution to the rear wheels 26 during acceleration. This is substantially the same effect as moving the center of rotation C of the vehicle body 101 rearward. Therefore, by adjusting the suspension to lower the vehicle height at the front of the electric vehicle 100, the range of variation of the center of rotation C due to the adjustment of the driving force distribution is substantially changed (shifted or expanded) rearward.

On the other hand, if the length (height) of the front suspension 31 and the rear suspension 32 is adjusted to lower the vehicle height at the rear of the electric vehicle 100 relative to the vehicle height at the front, the vehicle body 101 assumes a posture similar to that of a nose-up vehicle from the beginning. Therefore, adjusting the suspension to lower the vehicle height at the rear of the electric vehicle 100 has substantially the same effect as adjusting the driving force distribution to suppress nose dive. In the electric vehicle 100 of this embodiment, adjusting the suspension to lower the vehicle height at the rear of the electric vehicle 100 corresponds to adjusting to increase the driving force distribution to the front wheels 21 during deceleration. This is substantially the same effect as moving the center of rotation C of the vehicle body 101 forward. Therefore, by adjusting the suspension to lower the vehicle height at the rear of the electric vehicle 100, the range of variation of the center of rotation C due to the adjustment of the driving force distribution is substantially shifted forward or expanded.

Also, when adjusting the damping force (stiffness) of the front suspension 31 or rear suspension 32, the range of variation of the center of rotation C caused by adjusting the drive force distribution is substantially shifted or expanded, just as when adjusting the vehicle height as described above.

Therefore, as shown in FIG. 11, by also adjusting the suspension, the range of variation of the center of rotation C becomes wider than the range of variation _R0 achieved only by adjusting the drive force distribution, and the center of rotation C can be adjusted substantially within the range of variation R _EX .

In addition, when the damping forces of both the front suspension 31 and the rear suspension 32 are increased, the change in posture of the electric vehicle 100 is suppressed. In other words, the occurrence and fluctuation of the pitch angle _θP is suppressed. Therefore, in the head movement suppression control, when the damping forces of both the front suspension 31 and the rear suspension 32 are increased, the pitch angle _θP becomes smaller, and the amount of head movement (r _α · _θP ) of the target occupant is reduced. As a result, car sickness of the target occupant is easily suppressed.

12 is a flow chart relating to the head movement suppression control in the case where the movement of the rotation center C is assisted by adjusting the suspension. As shown in FIG. 12, in step S20, when the seat selector 13 accepts the selection of the target seat S 1 _S in which the target occupant who should be suppressed from car sickness sits, in step S21, the reference position setting unit 51 checks whether the target seat S _{1 S} is the driver's seat or the passenger seat (front seat 33). In step S21, if the target seat S _{1 S} is the driver's seat or the passenger seat, the process proceeds to step S22, where the reference position setting unit 51 sets the reference position to the position L ₁ of the head H ₁ of the occupant P ₁ sitting in the front seat 33. On the other hand, in step S11, if the target seat S _{1 S} is the rear seat 34, the process proceeds to step S23, where the reference position setting unit 51 sets the reference position to the position L ₂ of the head H ₂ of the occupant P ₂ sitting in the rear seat 34. These steps are the same as those in the first embodiment.

Thereafter, in step S24, the controller 12 checks whether or not it is possible to move the center of rotation C of the vehicle body 101 to the set reference position simply by adjusting the drive force distribution. For each suspension setting state, the range (R ₀ ) within which the center of rotation C can be moved by adjusting the drive force distribution can be calculated. Therefore, the controller 12 checks whether or not it is possible to move the center of rotation C of the vehicle body 101 to the set reference position by calculating the range (R ₀ ) within which the center of rotation C can be moved by adjusting the drive force distribution according to the suspension setting state. In this case, the controller 12 functions as a rotation center movement range calculation unit that calculates the range (R ₀ ) within which the center of rotation C can be moved by adjusting the drive force distribution.

If it is determined in step S24 that the set reference position is within the range (R ₀ ) in which the center of rotation C can be moved by adjusting the drive force distribution, the process proceeds to step S26, where the amount and direction of movement of the target occupant's head are detected, and in step S27, a corrected position according to the specific amount and direction of movement of the target occupant's head is calculated. Then, in step S28, a corrected drive force distribution ( _TF2 ^* , _TR2 ^* ) for head movement suppression control that causes the center of rotation C of the vehicle body 101 to follow the corrected position is calculated, and in step S29, the front wheels 21 and the rear wheels 26 are driven according to this corrected drive force distribution ( _TF2 ^* , _TR2 ^* ) for head movement suppression control. Each of these steps is the same as in the first embodiment.

On the other hand, if it is determined in step S24 that the set reference position is not within the range (R ₀ ) in which the center of rotation C can be moved by adjusting the driving force distribution, the process proceeds to step S25. In step S25, the controller 12 adjusts the front suspension 31 or the rear suspension 32. This changes the balance of the vehicle height of the electric vehicle 100, the damping force of the suspension, or both, and the range in which the center of rotation C can be moved by adjusting the driving force distribution is transitioned or expanded to a range (R _EX ) that includes the reference position with a margin that can include fluctuations in the corrected position. Then, the process proceeds to step S26. Steps from S26 onwards are as described above.

In this way, in the head movement suppression control, when the movement of the center of rotation C is assisted by adjusting the suspension, the movement of the head of the target occupant is suppressed even if the reference position is not within the range (R ₀ ) in which the center of rotation C can be moved by adjusting the drive force distribution. As a result, car sickness of the target occupant can be more reliably suppressed.

13 is a flow chart relating to head movement suppression control in the case where suppression of occurrence and variation of pitch angle θ _P is assisted by adjusting the suspension. As shown in FIG. 13, in the case where suppression of occurrence and variation of pitch angle θ _P is assisted by adjusting the suspension, each step from selection of the target seat SS (step S10) to driving of the front wheels 21 and the rear wheels 26 (step S17) is the same as that in the first embodiment. Then, when the front wheels 21 and the rear wheels 26 are driven according to the corrected driving force distribution ( _TF2 ^* , _TR2 ^* ) in step S17, the process proceeds to step S31, where the controller 12 checks whether or not the movement of the head of the target occupant has been suppressed. For example, the controller 12 monitors the head movement detection result by the head movement detection unit 44, and checks whether or not the movement of the head of the target occupant has been suppressed. In this embodiment, the controller 12 sets a movement amount threshold value for the movement amount (displacement relative to the reference position) of the head of the target occupant, and sets an acceleration threshold value for the acceleration of the head of the target occupant. The controller 12 determines that the movement of the head of the target occupant has been suppressed when the detected amount of movement is equal to or less than the movement amount threshold and the detected acceleration is equal to or less than the acceleration threshold. In this case, the controller 12 functions as a head movement suppression determination unit.

If it is determined in step S31 that the head movement of the target occupant has been suppressed, there is no need to adjust the suspension, and the calculation for this control cycle ends. On the other hand, if it is determined in step S31 that the head movement of the target occupant has not been suppressed, the process proceeds to step S32. Then, in step S32, the controller 12 increases the damping forces of the front suspension 31 and the rear suspension 32 to suppress the occurrence and variation of the pitch angle _θP . This increases the probability that the head movement of the target occupant will be suppressed in the next control cycle.

In this way, in the head movement suppression control, the generation and variation of the pitch angle θ _P is assisted by adjusting the suspension, so that the head movement of the target occupant is more reliably suppressed. As a result, car sickness of the target occupant can be more reliably suppressed.

In addition, among the suspension adjustments in the second embodiment, the adjustments of the front suspension 31 and the rear suspension 32 that change the vehicle height or the damping force can also be used to adjust the movement direction of the target occupant's head. For example, since the center of rotation C of the vehicle body 101 moves forward and backward in the electric vehicle 100 by adjusting the drive force distribution, the head movement that is easier to suppress by adjusting the drive force distribution is movement in the forward and backward direction of the electric vehicle 100. Therefore, the more the movement direction of the target occupant's head is along the forward and backward direction of the electric vehicle 100, the more accurately and reliably the head movement of the target occupant is suppressed by adjusting the drive force distribution. Therefore, by aligning the movement direction of the target occupant's head with the forward and backward direction of the electric vehicle 100 by adjusting the suspension (adjusting the vehicle height or the damping force), the head movement of the target occupant is accurately and reliably suppressed by the head movement suppression control. Therefore, car sickness of the target occupant is more reliably suppressed.

As described above, the control method (head movement suppression control) for an electric vehicle according to the first and second embodiments is a control method for an electric vehicle 100 that controls the attitude of the vehicle body 101 in the fore-and-aft direction by adjusting the drive force distribution between the front wheels 21 and the rear wheels 26, which are the drive wheels. In this control method for an electric vehicle, the selection of one seat (target seat S _S ) out of a plurality of seats is accepted, and a reference position (e.g., L ₁ ) corresponding to the selected seat (target seat S _S ) is set. Then, the drive force distribution is adjusted to move the center of rotation C of the vehicle body 101 to the reference position.

In this way, when the center of rotation C of the vehicle body 101 is moved to a reference position corresponding to the target seat S _S in which the target occupant whose car sickness should be suppressed sits, the movement of the head of the target occupant is suppressed. In particular, the amount of movement of the head of the target occupant, i.e., the amount of displacement from the reference position, is suppressed. Furthermore, this suppression action is more direct and effective than the case where the head movement is indirectly suppressed by suppressing the pitch angle θ _P. Therefore, according to the control method (head movement suppression control) for the electric vehicle according to the first and second embodiments, car sickness of the target occupant is more easily suppressed than in the past.

In particular, in the first and second embodiments, movement of the head (e.g., H ₁ ) of an occupant (target occupant) sitting in a selected seat (target seat S _S ) is detected, and a corrected position (e.g., position from C _α ⁺ to C _α ^- ) moving around a reference position (e.g., L ₁ ) is calculated in accordance with the movement of the head. Then, by adjusting the drive force distribution, the center of rotation C of the vehicle body 101 moves around the reference position to follow the corrected position.

In this way, by finely adjusting the center of rotation C of the vehicle body 101 around the reference position in response to the actual movement of the head of the target occupant, the movement of the head can be further reliably suppressed. In particular, this control can absorb differences in physique, muscle mass, etc., which differ depending on the occupant. That is, when a certain pitch angle θ _P occurs, the specific amount of head movement, etc. usually differs depending on the specific physique, muscle mass, etc., of the target occupant. However, the above control can accurately suppress the movement of the head depending on the target occupant, regardless of the individual differences in the physique, muscle mass, etc., of the target occupant. Furthermore, when the head moves due to the occurrence of a certain pitch angle θ _P , a rocking back occurs, but the above control can reduce such a rocking back. Therefore, car sickness of the target occupant can be particularly suppressed.

In the first and second embodiments, the direction and amount of head movement of the target occupant's head (e.g., H ₁ ) are detected, and the correction position (e.g., position from C _α ⁺ to C _α ⁻ ) moves in the opposite direction to the head movement direction according to the amount of head movement (r _α ·θ _P ).

In this way, by making the center of rotation C follow a corrected position that moves in the exact opposite direction to the movement of the target occupant's head, the effect of suppressing head movement is particularly improved. In addition, the effect of suppressing head movement according to the target occupant and the effect of reducing swing-back are also improved.

In the first and second embodiments described above, by moving the center of rotation C of the vehicle body 101 to a correction position (for example, from C _α ⁺ to C _α ^- position), the inclination (θ _{P )} of the vehicle body 101 in the fore-and-aft direction may be increased compared to when the center of rotation C of the vehicle body 101 is maintained at the reference position (for example, L ₁ ).

In this way, if the center of rotation C of the vehicle body 101 is also moved in the direction in which the pitch angle θ _P increases, the swing back is particularly likely to be reduced.

In the second embodiment, in addition to adjusting the drive force distribution, the suspension of the front wheels 21 or the rear wheels 26 is adjusted.

In this way, when the suspension is adjusted in the head movement suppression control, the range in which the center of rotation C of the vehicle body 101 can move due to the adjustment of the drive force distribution is shifted or expanded, or the pitch angle θ _P is reduced, which makes it easier to suppress the movement of the head of the target occupant.

In the above second embodiment, the range (R 0 ) within which the center of rotation C of the vehicle body 101 can move is shifted or expanded to include a reference position (e.g., L ₁ ) by adjusting the damping force of the suspension of the front wheels 21 or the rear wheels 26, or by adjusting the vehicle height using the suspension of the front wheels 21 or the rear wheels ₂₆ , thereby adjusting the distribution of driving force.

In this way, in the head movement suppression control, when the vehicle height of electric vehicle 100 is adjusted by adjusting the suspension or the damping force of the suspension is adjusted, the range in which center of rotation C of vehicle body 101 can move by adjusting the drive force distribution is shifted or expanded. Therefore, even if the reference position is not within the range (R ₀ ) in which center of rotation C can be moved by adjusting the drive force distribution, movement of the head of the target occupant can be suppressed. Therefore, car sickness of the target occupant can be more reliably suppressed.

In the second embodiment, the damping force in the suspension of both the front wheels 21 and the rear wheels 26 is increased.

In this way, by increasing the damping forces of both the front suspension 31 and the rear suspension 32 in the head movement suppression control, the change in the attitude (θ _P ) of the vehicle body 101 is further suppressed. Therefore, even if a pitch angle θ _P occurs, the amount of head movement of the target occupant due to this is suppressed. Therefore, car sickness of the target occupant can be more reliably suppressed.

In the above second embodiment, the direction of movement of the head of the occupant in the selected seat (target seat S S ₎ is made to coincide with the fore-and-aft direction of the electric vehicle 100 by adjusting the damping force of the suspension of the front wheels 21 or the rear wheels 26, or by adjusting the vehicle height using the suspension of the front wheels 21 or the rear wheels 26.

In this way, by adjusting the suspension to align the head movement direction of the target occupant in the target seat _S with the front-rear direction of the electric vehicle 100, the head movement suppression control more accurately and reliably suppresses the head movement of the target occupant. As a result, car sickness of the target occupant can be more reliably suppressed.

The control device for an electric vehicle according to the first and second embodiments is a control device for an electric vehicle 100 that controls the posture of a vehicle body 101 in the longitudinal direction by adjusting the drive force distribution to the drive wheels, that is, the front wheels 21 and the rear wheels 26. This control device includes a seat selector 13 that accepts the selection of one seat (target seat S _S ) out of a plurality of seats, a reference position setting unit 51 that sets a reference position (e.g., L ₁ ) according to the selected seat (target seat S _S ), and a drive force setting unit 45 that moves the center of rotation C of the vehicle body 101 to the reference position (e.g., L ₁ ) by adjusting the drive force distribution.

This control device for an electric vehicle moves the center of rotation C of the vehicle body 101 to a reference position corresponding to the target seat S _S in which the target occupant who should be suppressed from experiencing car sickness sits. This suppresses movement of the head of the target occupant in the target seat S _S. In particular, the amount of movement of the target occupant's head, i.e., the amount of displacement from the reference position, is suppressed. This suppression action is more direct and effective than the case where head movement is indirectly suppressed by suppressing the pitch angle θ _P. Therefore, according to the control device for an electric vehicle according to the first and second embodiments, car sickness of the target occupant is more easily suppressed than in the past.

The above describes an embodiment of the present invention, but the configurations described in the above embodiment merely show some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

Claims (9)

1. A method for controlling an electric vehicle, which controls a vehicle body attitude in a longitudinal direction by adjusting a driving force distribution between front and rear drive wheels, comprising:
   Accepting a selection of one of a plurality of seats;
   Setting a reference position according to the selected seat;
   By adjusting the drive force distribution, the rotation center of the vehicle body is moved to the reference position.
   A method for controlling an electric vehicle.
2. A method for controlling an electric vehicle according to claim 1,
   Detecting head movement of an occupant in the selected seat;
   Calculating a correction position that moves around the reference position in response to the movement of the head;
   By adjusting the drive force distribution, the rotation center of the vehicle body is moved so as to follow the corrected position with the reference position as a center.
   A method for controlling an electric vehicle.
3. A method for controlling an electric vehicle according to claim 2, comprising:
   Detecting a direction of movement of the head and an amount of movement of the head as the movement of the head;
   the correction position moves in a direction opposite to the movement direction of the head in accordance with the amount of movement of the head.
   A method for controlling an electric vehicle.
4. A method for controlling an electric vehicle according to claim 2, comprising:
   By moving the rotation center of the vehicle body to the correction position, the inclination of the vehicle body in the front-rear direction is increased compared to a case in which the rotation center of the vehicle body is maintained at the reference position.
   A method for controlling an electric vehicle.
5. A method for controlling an electric vehicle according to any one of claims 1 to 4, comprising:
   In addition to adjusting the drive force distribution, a suspension of the front wheels or the rear wheels is adjusted.
   A method for controlling an electric vehicle.
6. A method for controlling an electric vehicle according to claim 5,
   by adjusting the damping force of the suspension of the front wheels or the rear wheels, or by adjusting the vehicle height using the suspension of the front wheels or the rear wheels, the range in which the center of rotation of the vehicle body can move due to the adjustment of the driving force distribution is shifted or expanded to include the reference position.
   A method for controlling an electric vehicle.
7. A method for controlling an electric vehicle according to claim 5,
   Increasing the damping forces in both the front and rear wheel suspensions;
   A method for controlling an electric vehicle.
8. A method for controlling an electric vehicle according to claim 5,
   By adjusting a damping force of a suspension of the front wheels or the rear wheels, or by adjusting a vehicle height using a suspension of the front wheels or the rear wheels, a moving direction of the head of the occupant in the selected seat is made to coincide with the front-rear direction of the electric vehicle.
   A method for controlling an electric vehicle.
9. A control device for an electric vehicle that controls a vehicle body posture in a longitudinal direction by adjusting a driving force distribution between front wheels and rear wheels, which are driving wheels,
   a seat selector for accepting a selection of one of a plurality of seats;
   a reference position setting unit that sets a reference position according to the selected seat;
   a driving force setting unit that adjusts the driving force distribution to move the rotation center of the vehicle body to the reference position;
   A control device for an electric vehicle comprising:

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