Control method for electric vehicles, and control device for electric vehicles

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

[Technical Field]

[0001] The present invention relates to a control method for electric vehicles and a control device for electric vehicles. [Background technology]

[0002] JP4876534B2 discloses a technology for reducing the pitch rate of an in-wheel motor type vehicle when the vehicle passes over bumps or uneven surfaces in the road, in which the suspension effect cannot be fully obtained. More specifically, it discloses applying different braking and driving forces to the front and rear wheels, and then, if a change in pitch rate is detected, applying different braking and driving forces to the left and right wheels at a predetermined interval. [Overview of the project]

[0003] Conventionally, electric vehicles are known that control their attitude by adjusting the distribution of driving force to multiple drive wheels. In such electric vehicles, attitude is generally controlled by adjusting the distribution of driving force through feedback control, which feeds back detected values ​​such as pitch rate. In other words, in conventional electric vehicles, attitude control works to follow already occurring attitude fluctuations, for example, to cancel them out, so the attitude control may not be effectively timely.

[0004] Furthermore, when the torque distribution is adjustable, it is usually determined to optimize energy efficiency while considering driving stability. Therefore, when attitude control is performed by adjusting the torque distribution, the torque distribution is shifted from the torque distribution that optimizes energy efficiency to the torque distribution that controls attitude, thus worsening energy efficiency. For this reason, it is desirable to keep attitude control by adjusting the torque distribution off (not in operation) as much as possible, and only turn it on (in operation) when necessary, even if it means a trade-off with energy efficiency.

[0005] However, as described above, when attitude control is turned on / off as needed by adjusting the drive force distribution, if the start of attitude control is determined using detected values ​​such as pitch rate, the decision to start attitude control is made based on attitude changes that have already occurred, resulting in a delay in the decision 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 effectively unable to keep up increases. This is particularly noticeable when attitude control is performed by feedback control, but the same applies when attitude control is performed by feedforward control. In other words, when attitude control is turned on / off as needed, even if attitude control is performed by feedforward control, if the decision to start attitude control is made using detected values ​​such as pitch rate, the delay in the decision to start attitude control may result in the attitude control being effectively unable to keep up.

[0006] Therefore, the present invention aims to provide a control method for an electric vehicle and a control device for an electric vehicle that reduce the delay in determining when to start attitude control by adjusting the driving force distribution, and enable timely implementation of attitude control.

[0007] One aspect of the present invention is a control method for an electric vehicle that performs attitude control to control the vehicle's posture in the longitudinal direction by adjusting the distribution of driving force between the front and rear wheels, which are the 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. Based on this total driving force, an estimated acceleration, which is an estimated value of the acceleration that occurs when the electric vehicle is driven by that total driving force, or an estimated jerk, which is an estimated value of the jerk, which is the rate of change of acceleration over time, is calculated. Then, based on the estimated acceleration or estimated jerk, an attitude control execution determination is made to switch the attitude control on or off. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an explanatory diagram showing the schematic configuration of an electric vehicle. [Figure 2] Figure 2 is an explanatory diagram showing the schematic structure of the chassis system. [Figure 3] Figure 3 is a graph showing the lower limit of the pitch angle that an occupant of an electric vehicle can perceive during acceleration. [Figure 4] Figure 4 is a block diagram showing the configuration of the controller 12 for attitude control. [Figure 5] Figure 5 is a block diagram showing the configuration of the attitude control execution determination unit. [Figure 6] Figure 6 is a flowchart showing the effects of turning attitude control on and off in electric vehicles. [Figure 7] Figure 7 is a time chart showing the parameter changes when attitude control switches from off to on. [Figure 8] Figure 8 is a block diagram showing the configuration of the attitude control execution determination unit in the second embodiment. [Figure 9] Figure 9 is a flowchart showing the operation related to the on / off of attitude control in the electric vehicle of the second embodiment. [Figure 10] Figure 10 is a block diagram showing the configuration for updating the coefficients of the approximation formula used in calculating running resistance. [Figure 11] Figure 11 is an explanatory diagram showing a specific method for updating the coefficients of the approximation formula used in calculating running resistance. [Figure 12] Figure 12 is a flowchart showing the process of updating the coefficients of the approximation formula used in calculating running resistance. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings.

[0010] [First Embodiment] <Configuration of electric vehicles> Figure 1 is an explanatory diagram showing the schematic configuration of the electric vehicle 100. The electric vehicle 100 is, for example, an electric vehicle or a hybrid vehicle, which is a vehicle that can drive or brake one or more drive wheels with 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 each of the multiple drive wheels can be controlled (adjusted). Specifically, as shown in Figure 1, the electric vehicle 100 includes a front-wheel drive system 10, a rear-wheel drive system 11, and a controller 12.

[0011] 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.

[0012] The front inverter 22 drives the front motor 23 by converting the DC power output by a battery (not shown) into AC power and supplying it to the front motor 23. Also, when the front motor 23 is rotated by the front wheels 21, the front inverter 22 charges the battery by converting the regenerative AC power generated by the front motor 23 into DC power and inputting it to the battery.

[0013] 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 the driving force (hereinafter referred to as front wheel driving force F) is transmitted to the front wheels 21. F This causes the following to occur.

[0014] 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.

[0015] The rear inverter 27 drives the rear motor 28 by converting the DC power output by the battery into AC power and supplying it to the rear motor 28. Also, when the rear motor 28 is rotated by the rear wheels 26, the rear inverter 27 charges the battery by converting the regenerative AC power generated by the rear motor 28 into DC power and inputting it to the battery.

[0016] The rear motor 28 is an electric motor that drives the rear wheels 26. The rear motor 28 is, 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, providing the rear wheels 26 with driving force (hereinafter referred to as rear wheel driving force F). R This causes the following to occur.

[0017] The controller 12 consists 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 in a predetermined control cycle. In this embodiment, the controller 12 is a control device for the electric vehicle 100 that performs attitude control to control the attitude in the longitudinal direction by adjusting the distribution of driving force between the front wheels 21 and the rear wheels 26, which are the drive wheels.

[0018] The controller 12 distributes the driving force (hereinafter referred to as the total driving force TQ) requested by, for example, the operation of the accelerator pedal (not shown) to the front wheels 21 and rear wheels 26, which are the drive wheels. The controller 12 then distributes the front wheel driving force F according to that distribution. F and rear-wheel drive force F R The front wheels 21 and rear wheels 26 are driven by the front-wheel drive system 10 and the rear-wheel drive system 11, respectively, so that this occurs. Furthermore, in this embodiment, the controller 12 is programmed to perform attitude control to control the longitudinal attitude of the electric vehicle 100 by adjusting the power distribution between the front wheels 21 and the rear wheels 26 as needed.

[0019] When controlling the operation of the electric vehicle 100, the controller 12 can appropriately acquire various parameters representing the operation state of the electric vehicle 100, etc., by sensors (not shown) or by calculation. For example, the electric vehicle 100 includes an accelerator opening sensor (not shown) that detects the accelerator opening A PO Therefore, the controller 12 can appropriately acquire the accelerator opening A PO The accelerator opening A PO is a parameter representing the operation amount of the accelerator pedal. Also, the controller 12 appropriately acquires the vehicle speed VSP of the electric vehicle 100 by a sensor (not shown) or by calculation.

[0020] Furthermore, in this embodiment, the electric vehicle 100 includes an acceleration sensor (not shown) that measures the acceleration generated in the electric vehicle 100 (hereinafter referred to as the actual acceleration G act ). Therefore, the controller 12 can appropriately acquire the actual acceleration G act . Also, the controller 12 can appropriately acquire the jerk (hereinafter referred to as the actual jerk J act ), which is the time change rate of the acceleration generated in the electric vehicle 100, by differentiating the actual acceleration G act .

[0021] In addition, the controller 12 can appropriately acquire the current location of the electric vehicle 100 and the gradient of the road surface on which the electric vehicle 100 travels, etc. (hereinafter referred to as the road surface gradient φ LS ) from a car navigation system (not shown). Note that the road surface gradient φ LS 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 gradient φ LS is obtained from the car navigation system.

[0022] <Principle of attitude control by drive force distribution> Figure 2 is an explanatory diagram showing the schematic structure of the chassis system. As shown in Figure 2, the front wheels 21 are connected to the vehicle body, which is the part of the vehicle body where the passenger compartment and other components are formed, via the front suspension 31. Similarly, the rear wheels 26 are connected to the vehicle body 101 via the rear suspension 32.

[0023] For example, front-wheel drive force F F Rear-wheel drive force F R If the electric vehicle 100 is accelerated by either of these, the load shifts to the rear (negative side in the X direction) of the electric vehicle 100. As a result, the center of gravity O G Centered at, pitch angle θ P A moment is generated that acts in a direction that increases the force. Therefore, when the electric vehicle 100 accelerates, in principle, the electric vehicle 100 will assume a posture in which the front part, which is the part on the positive X direction, is lifted up (a so-called nose-up posture).

[0024] On the other hand, front-wheel drive force F F The torque of the front motor 23 that generates the front torque (hereinafter referred to as front torque) acts on the vehicle body 101 via the front suspension 31. Specifically, the front torque is generated around the virtual center of rotation O F Around the pitch angle θ P This generates a moment that acts in a direction that reduces the force. That is, when the electric vehicle 100 accelerates, the front torque suppresses nose-up. Similarly, the rear-wheel drive force F R The torque generated by the rear motor 28 (hereinafter referred to as rear torque) acts on the vehicle body 101 via the rear suspension 32, creating a virtual rotation center O R Around the pitch angle θ P This generates a moment that acts in a direction that reduces the force. Therefore, when the electric vehicle 100 accelerates, the rear torque suppresses nose-up.

[0025] Furthermore, the magnitude of the effect of front torque on suppressing nose-up during acceleration is determined by the anti-scat angle θ. FIt depends on the magnitude of the anti-scat angle θ. Similarly, the magnitude of the effect of rear torque on suppressing nose-up during acceleration is related to the anti-scat angle θ. R It depends on the magnitude of the anti-scut angle. Therefore, by adjusting the drive force distribution of the front wheels 21 and rear wheels 26 so that a larger distribution is given to the drive wheels with a relatively large anti-scut angle, the effect of suppressing nose-up while maintaining the total drive force is increased. Accordingly, in this embodiment, the controller 12 adjusts the drive force distribution of the front wheels 21 and rear wheels 26 to control the longitudinal attitude of the electric vehicle 100 (i.e., the pitch angle θ). P Performs attitude control to regulate (or its fluctuations).

[0026] Note that the virtual rotation center O F This is the instantaneous and virtual center of rotation generated in the vehicle body (especially the vehicle upper 101) by the transmission of front torque, and is predetermined by the specific configuration of the front suspension 31, etc. Similarly, the virtual center of rotation O of the rear part R This is the instantaneous and virtual center of rotation generated in the vehicle body (especially the vehicle upper 101) by the transmission of rear torque, and is predetermined by the specific configuration of the rear suspension 32, etc. Also, the anti-scat angle θ F In the XZ plane, the rotation center of the front wheel 21 and the virtual rotation center O F It is the angle formed by the line connecting the two points and the line parallel to the road surface. Similarly, the anti-scut angle θ R In the XZ plane, the rotation center of the rear wheel 26 and the virtual rotation center O R It is the angle formed by the line connecting the two points and the line parallel to the road surface.

[0027] In this embodiment, as shown in Figure 2, the anti-scut angle θ of the rear suspension 32 R The anti-scat angle θ of the front suspension 31 is F It is larger than that. For this reason, for example, when accelerating, the pitch angle θ P When suppressing or reducing the increase of the force, the controller 12 relatively increases the distribution of driving force to the rear wheels 26.

[0028] Here, the relationship between the chassis system configuration and attitude control during acceleration has been explained, but the controller 12 also performs attitude control during deceleration by adjusting the driving force distribution between the front wheels 21 and the rear wheels 26. However, during deceleration, contrary to the above, the electric vehicle 100 assumes a posture in which the front part sinks (a so-called nose-dive posture), so the controller 12 adjusts the driving force distribution between the front wheels 21 and the rear wheels 26 accordingly. Furthermore, unless otherwise specified below, the attitude of the electric vehicle 100 refers to the attitude in the longitudinal direction, i.e., the pitch angle θ P This refers to: In other words, attitude control by adjusting the driving force distribution is performed by adjusting the pitch angle θ. P Control of pitch rate Δ P Control of the pitch angle θ P and pitch rate Δ P This is the control of the pitch rate Δ. P The pitch angle θ is P This is the rate of change over time.

[0029] <Desired attitude> Figure 3 shows the pitch angle θ that an occupant of the electric vehicle 100 can experience during acceleration. P This graph shows the lower limit of LL. As shown in Figure 3, the pitch angle θ that occupants can feel during acceleration. P There is a lower limit LL for this. That is, the pitch angle θ P When the pitch angle θ is around the lower limit LL or a smaller value, the crew P It is difficult to perceive the occurrence and fluctuations of these phenomena.

[0030] And this lower limit LL is the pitch rate Δ P It depends on the pitch rate Δ. Specifically, P The larger the pitch angle θ, the greater the perceived pitch angle. P The lower limit LL becomes smaller. That is, the pitch rate Δ P Large pitch angle θ P When the pitch angle θ fluctuates rapidly, P Even if it is small, the crew will have a pitch angle θ P It senses the fluctuations in pitch rate Δ. P The pitch angle θ is small. PWhen it fluctuates slowly, the pitch angle θ P Even if it is relatively large, the crew will be at a pitch angle θ P It is difficult to perceive these fluctuations.

[0031] Pitch angle θ P The occurrence or fluctuation of this usually does not cause much trouble to the stable running (running stability) of the electric vehicle 100, but it may worsen the ride comfort of the electric vehicle 100. For this reason, the controller 12 controls the pitch angle θ P Attitude control is performed by adjusting the drive force distribution so that the value is generally below the lower limit LL.

[0032] However, in this embodiment, the pitch angle θ to be controlled by attitude control is... P An upper limit value UL is set in advance through experiments or simulations. The upper limit value UL is, for example, the pitch rate Δ P It is a constant value that does not depend on [something].

[0033] Then, the controller 12 controls the pitch angle θ. P The value is within the range of lower limit LL and upper limit UL (region E) 2a When the value (inside) is reached, attitude control is performed by adjusting the driving force distribution. As a result, the controller 12 controls the pitch angle θ P The longitudinal attitude of the electric vehicle 100 is controlled so that the pitch angle θ is within the range of the lower limit LL (a value within region E1). Typically, the target attitude of the electric vehicle 100 is the pitch angle θ P This is the attitude where the pitch angle θ is zero. In this embodiment, when the controller 12 performs attitude control, P This is effectively zero or any other predetermined angle (hereinafter referred to as the target pitch angle θ). P * The forward and backward attitude is controlled to maintain the following (pitch angle θ). P The predetermined angle may change depending on the specific driving conditions of the electric vehicle 100.

[0034] On the other hand, the pitch angle θ PWhen the value is initially within the range of the lower limit LL (a value within region E1), or when the pitch angle θ P Values ​​in the range that exceed the upper limit UL (region E) 2b When the value is (indicated by the internal value), the controller 12 does not perform attitude control by adjusting the driving force distribution.

[0035] In other words, the controller 12 does not perform attitude control at all times, but rather performs an attitude control execution determination to switch attitude control on or off as needed. Specifically, when the attitude control execution determination determines that it is necessary to perform attitude control, the controller 12 turns on attitude control. As a result, attitude control is started or maintained in an active state. On the other hand, when the attitude control execution determination determines that it is not necessary to perform attitude control, the controller 12 turns off attitude control. As a result, attitude control is stopped or maintained in a stopped state.

[0036] More specifically, the controller 12 controls the pitch angle θ P Area abnormal 2a When the value falls within this range, it is determined that attitude control is necessary, and attitude control is turned on. Meanwhile, the pitch angle θ P is region E1 or region E 2b When the value becomes such that the controller 12 determines that it does not need to perform attitude control and turns off attitude control.

[0037] As shown in Figure 3, the pitch angle θ P This is positively correlated with the acceleration G generated in the electric vehicle 100, and the pitch rate Δ P This has a positive correlation with the jerk J, which is the rate of change over time of the acceleration G occurring in the electric vehicle 100. Therefore, the controller 12 determines the pitch angle θ that the occupant can perceive based on the acceleration G, the jerk J, or both of these. P The lower limit value LL, etc., can be identified. Therefore, the controller 12 can make a decision on whether to perform attitude control based on acceleration G, jerk J, or both.

[0038] The controller 12 acquires the actual acceleration G act and the actual jerk J act Therefore, it is possible to determine whether to execute attitude control based on the actual acceleration G act and / or the actual jerk J act However, in this embodiment, instead of the actual acceleration G act and / or the actual jerk J act , the controller 12 determines whether to execute attitude control based on the estimated acceleration G est and / or the estimated jerk J est This is to start attitude control without delay when attitude control is required. The estimated acceleration G est is an estimated value of the acceleration G that will occur in the electric vehicle 100 from now on. Similarly, the estimated jerk J est is an estimated value of the jerk J that will occur in the electric vehicle 100 from now on.

[0039] Incidentally, the lower limit value of the pitch angle θ P that the occupant of the electric vehicle 100 can feel during acceleration or deceleration also varies depending on the road surface gradient φ LS Specifically, when the road surface gradient φ LS is large, it becomes difficult for the occupant to feel the pitch angle θ P and its fluctuation. Therefore, the controller 12 can determine whether to execute attitude control 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, when the road surface gradient φ LS is greater than a predetermined threshold TH LS (predetermined gradient), and the road surface on which the electric vehicle 100 travels, etc., is a steep gradient and it is difficult for the occupant to feel the pitch angle θ P and its change, the controller 12 determines that attitude control is not necessary and turns off the attitude control. That is, when the road surface gradient φ LS is less than or equal to the threshold TH LS , and the estimated acceleration G est and / or the estimated jerk J estWhen the controller 12 determines that attitude control is necessary based on this, it turns on attitude control.

[0040] <Configuration for attitude control> Figure 4 is a block diagram showing the configuration of the controller 12 for attitude control. As shown in Figure 4, the controller 12 includes a total drive force calculation unit 41, a basic distribution calculation unit 42, an attitude control calculation unit 43, a drive force setting unit 44, a front motor control unit 45, and a rear motor control unit 46.

[0041] 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 the required driving force for the electric vehicle 100. For example, the total driving force calculation unit 41 calculates the accelerator opening A PO It has a map that associates the total driving force TQ with the accelerator opening A, and by referring to this map, the accelerator opening A PO The total driving force TQ corresponding to this is calculated.

[0042] Furthermore, the total driving force calculation unit 41 calculates the accelerator opening A as described above. PO Instead of calculating the total driving force TQ based on the driver's actions, the total driving force TQ can be calculated based on commands from an ADAS (Advanced Drive Assistance System) or AD (Autonomous Driving) system, etc. Since these systems are systems that substitute for the driver's operation of the accelerator pedal, the calculation of the total driving force TQ performed by the total driving force calculation unit 41 based on commands from these systems is essentially a calculation based on the operation of the accelerator pedal.

[0043] 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 determined to achieve the best possible energy efficiency while ensuring driving stability, and is predetermined by experimentation or simulation. For example, if the front motor 23 and the rear motor 28 are of the same type and the electric vehicle 100 is traveling 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 conditions of the electric vehicle 100 (steering conditions, etc.).

[0044] In this embodiment, the basic distribution calculation unit 42 calculates the first front torque target value T based on the basic distribution and the total driving force TQ. F1 * , and the first rear torque target value T R1 * The first front torque target value T is calculated. F1 * This is the front-wheel drive force F according to the basic distribution. F This represents the front motor torque generated at the front wheel 21. The first rear torque target value T R1 * This is the rear-wheel drive force F according to the basic distribution. R This represents the rear torque generated at the rear wheel 26.

[0045] The attitude control calculation unit 43 determines whether attitude control is necessary and calculates a correction distribution, which is the driving force distribution for attitude control that should be set when attitude control is necessary. The correction distribution is determined to asymptotically bring the attitude of the electric vehicle 100 closer to the target attitude or to maintain it. Therefore, by distributing driving force to the front wheels 21 and rear wheels 26 according to the correction driving force distribution, the attitude of the electric vehicle 100 is controlled to reach the target attitude.

[0046] More specifically, the attitude control calculation unit 43 of this embodiment includes an attitude control execution determination unit 47 and a correction unit 48.

[0047] The attitude control execution determination unit 47 performs an attitude control execution determination based on the total driving force TQ and vehicle speed VSP, switching the attitude control on or off by adjusting the driving force distribution through feedforward control. In this embodiment, in addition to the total driving force TQ and vehicle speed VSP, the attitude control execution determination unit 47 also considers the road surface gradient φ. LS A decision on whether to execute attitude control is made based on this. The result of the attitude control execution decision is represented by the attitude control flag FLG. The attitude control flag FLG is a flag that, for example, is "1" (on) when attitude control is required and "0" (off) when attitude control is not required.

[0048] The correction unit 48 calculates the corrected driving force for the front wheels 21 and rear wheels 26 for attitude control by correcting the driving force of the front wheels 21 and rear wheels 26 (hereinafter referred to as the basic driving force) which is distributed according to the basic distribution. In this embodiment, the correction unit 48 calculates the first front torque target value T corresponding to the basic driving force. F1 * and the first rear torque target value T R1 * Based on this, the second front torque target value T corresponds to the corrected driving force. F2 * and the second rear torque target value T R2 * The correction unit 48 calculates the corrected driving force by feedforward control, for example, based on a predetermined vehicle model of the electric vehicle 100. In this embodiment, the corrected distribution is determined as a result of calculating the specific corrected driving force.

[0049] The drive force setting unit 44 sets the drive force generated by the front wheels 21 and rear wheels 26 to either the basic drive force or the corrected drive force, according to the attitude control flag FLG.

[0050] Specifically, when the attitude control execution determination determines that attitude control is unnecessary and the attitude control flag FLG is "0", the drive force setting unit 44 sets the drive force generated by the front wheels 21 and rear wheels 26 to the basic drive force. In other words, when the attitude control flag FLG is "0", the drive force setting unit 44 sets the first front torque target value T F1 * The first rear torque target value T is input to the front motor control unit 45. R1 * This is input to the rear motor control unit 46. As a result, attitude control is turned off.

[0051] On the other hand, if the attitude control execution determination determines that attitude control is necessary and the attitude control flag FLG is "1", the drive force setting unit 44 sets the drive force generated by the front wheels 21 and rear wheels 26 to a corrective drive force. That is, when the attitude control flag FLG is "1", the drive force setting unit 44 sets the second front torque target value T F2 * The value is input to the front motor control unit 45, and the second rear torque target value T is input. R2 * This is input to the rear motor control unit 46. This turns on attitude control.

[0052] 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. The first front torque target value T commands the basic driving force. F1 * When this is input, the front motor control unit 45 controls the front motor 23 to set the first front torque target value T F1 * This generates the corresponding front torque. Meanwhile, a second front torque target value T commands the corrective driving force for attitude control. F2 * When this is input, the front motor control unit 45 controls the front motor 23 to set the second front torque target value T F2 * This generates corresponding front torque. This results in front-wheel drive force FF It is controlled to either the basic driving force or the compensatory driving force.

[0053] 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 wheels 26. The first rear torque target value T commands the basic driving force. R1 * When this is input, the rear motor control unit 46 controls the rear motor 28 to set the first rear torque target value T R1 * This generates the corresponding rear torque. Meanwhile, a second rear torque target value T commands the corrective driving force for attitude control. R2 * When this is input, the rear motor control unit 46 controls the rear motor 28 to set the second rear torque target value T R2 * This generates rear torque corresponding to the rear-wheel drive force F R It is controlled to either the basic driving force or the compensatory driving force.

[0054] The front motor control unit 45 and the rear motor control unit 46 constitute a drive force control unit that controls the driving force of the front motor 23 and the rear motor 28 according to the basic distribution or corrected distribution.

[0055] Figure 5 is a block diagram showing the configuration of the attitude control execution determination unit 47. As shown in Figure 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 gradient determination unit 54, a pitch state determination unit 55, and a flag setting unit 56.

[0056] The running resistance calculation unit 51 calculates the running resistance RL [N] of the electric vehicle 100 based on the vehicle speed VSP [m / s]. The running resistance RL is composed of air resistance, rolling resistance, and acceleration resistance, and can be approximated by a quadratic function of the vehicle speed VSP as shown in equation (1) below. The coefficient A0 of the quadratic term, the coefficient A1 of the linear term, and the coefficient A2 representing the term that does not depend on the vehicle speed VSP (constant term) can be determined in advance, for example, by experiment or simulation. For this reason, the running resistance calculation unit 51 calculates the running resistance RL according to the vehicle speed VSP using the coefficients A0, A1, and A2 of each order.

[0057]

number

[0058] The acceleration estimation unit 52 estimates the acceleration G based on the total driving force TQ [Nm] and the running resistance RL. est [m / sec 2 The acceleration estimation unit 52 calculates the estimated acceleration G according to the equation of motion. est The acceleration estimation unit 52 calculates the estimated acceleration G as shown in the following equation (2). est The total driving force TQ, the running resistance RL, the known weight of the electric vehicle 100 (hereinafter referred to as vehicle weight M) [kg], and the acceleration due to gravity g [m / sec] are all factors. 2 ], and road surface gradient φ LS Using [deg], estimate acceleration G est The calculation is performed. Note that the estimated acceleration G calculated by the acceleration estimation unit 52 est This is an estimated value of the acceleration G that occurs when the electric vehicle 100 is driven with the total driving force TQ.

[0059]

number

[0060] The jerk estimation unit 53 estimates the acceleration G est Based on this, estimated jerk J est [m / sec 3The jerk estimation unit 53 calculates the estimated acceleration G as shown in the following formula (3). est By differentiating with respect to time, we can estimate the jerk J. est The estimated jerk J calculated by the jerk estimation unit 53 is calculated. est This is an estimated value of the rate of change of acceleration G (jerk J) that occurs when the electric vehicle 100 is driven with the total driving force TQ.

[0061]

number

[0062] The gradient determination unit 54 determines the road surface gradient φ LS Based on this, the feasibility of attitude control is determined. Specifically, the gradient determination unit 54 determines the road surface gradient φ LS and a predetermined threshold TH LS Compare it with the road surface gradient φ. LS is the threshold TH LS The gradient determination unit 54 determines that attitude control is possible when the following conditions are met. On the other hand, the road surface gradient φ LS is the threshold TH LS When the road surface gradient φ is greater than the specified value, the gradient determination unit 54 determines that attitude control is unnecessary. LS The threshold TH that is defined for LS This is determined by conformity through experiments or simulations, etc.

[0063] The pitch state determination unit 55 determines the pitch angle θ that occurs when the electric vehicle 100 is driven with the total driving force TQ. P Alternatively, based on the state of its fluctuations, the system determines whether attitude control is necessary. The pitch state determination unit 55 determines the pitch angle θ P The estimated acceleration G has a positive correlation with this. est , pitch rate Δ P Estimated jerk J, which has a positive correlation with est Based on either or both of these, it is possible to determine whether attitude control is necessary. In this embodiment, the pitch state determination unit 55 determines the estimated acceleration G est and estimated jerk J est Based on this, the necessity of posture control is determined.

[0064] Specifically, the pitch state determination unit 55 determines the estimated acceleration G est and estimated jerk J est The corresponding pitch angle θ P and pitch rate Δ P The system determines whether the combination of (hereinafter referred to as the pitch state) is something that the occupants can feel and is within the range that requires control. In other words, the pitch state determination unit 55 determines whether the resulting pitch state is within region E 2a It is determined whether the pitch state is within the range shown in Figure 3. 2a When the pitch state is within the range, the pitch state determination unit 55 determines that it is necessary to perform (turn on) attitude control. On the other hand, when the resulting pitch state is in region E 2a If the pitch state is not within the specified range, the pitch state determination unit 55 determines that attitude control is not required.

[0065] The above determination by the pitch state determination unit 55 is based on the pitch angle θ. P However, this is equivalent to determining whether the value is above the lower limit LL and below the upper limit UL. Therefore, the pitch state determination unit 55 determines, for example, the estimated acceleration G est The corresponding pitch angle θ P Estimated jerk J est Pitch rate Δ corresponding to P By comparing it with a preset lower limit value LL, it is possible to determine whether attitude control is necessary.

[0066] In this embodiment, the pitch state determination unit 55 determines whether attitude control is necessary in a particularly simple or approximate manner, as follows. That is, the pitch state determination unit 55 determines the estimated acceleration G est A predetermined threshold TH for this purpose G Set the (acceleration threshold) and estimate the jerk J est A predetermined threshold TH for this purpose J By setting a (jerk threshold), we can define the region where attitude control is particularly necessary. Then, we estimate the acceleration G. est is the threshold TH GThe above (and below the upper limit UL), and the estimated jerk J est is the threshold TH J When the above conditions are met, the pitch state determination unit 55 determines that it is necessary to perform attitude control (turn it on). In response to this, the estimated acceleration G est is the threshold TH G When it is smaller than or estimated jerk J est is the threshold TH J When the value is smaller than this, the pitch state determination unit 55 determines that attitude control is not required.

[0067] Estimated Jerk J est Threshold TH to set for J This is the estimated acceleration G est It can be a variable threshold that changes accordingly. Similarly, the estimated acceleration G est Threshold TH to set for G This is an estimated jerk J est It can be a variable threshold that changes accordingly.

[0068] Furthermore, the pitch angle θ at which the pitch state determination unit 55 determines that it is necessary to perform (turn on) attitude control is determined. P The ranges of these can be set substantially arbitrarily. Therefore, the pitch state determination unit 55 determines the estimated acceleration G est is the threshold TH G Above (and below the upper limit UL), or estimated jerk J est is the threshold TH J When any of the above conditions are met, it may be determined that attitude control must be activated (on). In this case, the estimated acceleration G est is the threshold TH G Smaller than, and estimated jerk J est is the threshold TH J When the value is smaller than this, the pitch state determination unit 55 determines that attitude control is not required.

[0069] The flag setting unit 56 sets the attitude control flag FLG based on the determination results from the gradient determination unit 54 and the pitch state determination unit 55. Specifically, when the gradient determination unit 54 determines that attitude control is not required, the flag setting unit 56 sets the attitude control flag FLG to "0" (off), regardless of the determination result from the pitch state determination unit 55. When the gradient determination unit 54 determines that attitude control is possible, the flag setting unit 56 sets the attitude control flag FLG based on the determination result from the pitch state determination unit 55. That is, when the gradient determination unit 54 determines that attitude control is possible and the pitch state determination unit 55 determines that attitude control is required (on), the flag setting unit 56 sets the attitude control flag FLG to "1" (on). On the other hand, when the gradient determination unit 54 determines that attitude control is possible, but the pitch state determination unit 55 determines that attitude control is not required, the flag setting unit 56 sets the attitude control flag FLG to "0" (off).

[0070] <effect> The following describes the attitude control of the electric vehicle 100 configured as described above, and in particular, the operation related to turning the attitude control on and off.

[0071] Figure 6 is a flowchart showing the operation related to the on / off of attitude control in the electric vehicle 100. As shown in Figure 6, the total driving force calculation unit 41 calculates the accelerator opening A in step S10. PO When obtained, in step S11, the obtained accelerator opening A PO Based on this, the total driving force TQ is calculated. Next, in step S12, the driving resistance calculation unit 51 calculates the driving resistance RL of the electric vehicle 100 based on the total driving force TQ and the vehicle speed VSP. Then, in step S13, the acceleration estimation unit 52 estimates the acceleration G based on the driving resistance RL. est The jerk estimation unit 53 calculates the estimated acceleration G in step S14. est Using this, estimate jerk J est Perform the calculation.

[0072] Subsequently, in step S15, the gradient determination unit 54 determines the road surface gradient φ LSObtain the acquired road surface gradient φ LS Based on this, determine whether attitude control is possible. Road surface gradient φ LS is greater than the threshold value TH LS , and when the road surface gradient φ LS is such that the occupant cannot feel the pitch angle θ P and its variation, proceed to step S19, and the attitude control is stopped, or the stopped state of the attitude control is maintained. On the other hand, when the road surface gradient φ LS is less than or equal to the threshold value TH LS , and the occupant can feel the pitch angle θ P and its variation, which may deteriorate the riding comfort of the electric vehicle 100, proceed to step S16, and based on the generated pitch state (θ P , Δ P ), determine whether attitude control is necessary.

[0073] 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 greater than or equal to the threshold value TH G , proceed to step S17, and the pitch state determination unit 55 further compares the estimated jerk J est with the threshold value TH J . And when the estimated jerk J est is greater than or equal to the threshold value TH J , that is, when both the estimated acceleration G est and the estimated jerk J est are greater than or equal to the respective threshold values TH G , TH J , it is determined that execution (on) of attitude control is necessary. Therefore, proceed to step S18, and the attitude control is executed, or the execution of the attitude control is maintained.

[0074] On the other hand, in step S16, when the estimated acceleration G est is less than the threshold value TH G , or in step S17, when the estimated jerk J est is less than the threshold value TH JWhen it is smaller, 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.

[0075] FIG. 7 is a time chart showing the transition of parameters when the attitude control switches from off to on. FIG. 7(A) shows the transition of the vehicle speed VSP. FIG. 7(B) shows the transition of the accelerator opening A PO FIG. 7(C) shows the transition of the total driving force TQ. FIG. 7(D) shows the transition of the acceleration G of the electric vehicle 100. In FIG. 7(D), the solid line indicates the estimated acceleration G est and the dashed-dotted line indicates the actual acceleration G act FIG. 7(E) shows the transition of the jerk J of the electric vehicle 100. In FIG. 7(E), the solid line indicates the estimated jerk J est and the dashed-dotted 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 the present embodiment in which the execution determination of the attitude control is performed by the feed-forward control based on the estimated acceleration G

[0076] and the estimated jerk J est In FIG. 7(F), the dashed-dotted line indicates the attitude control flag FLG in the comparative example in which the execution determination of the attitude control is performed by the feedback control based on the actual acceleration G est and the actual jerk J act or the pitch angle θ act and the pitch rate Δ P that actually occurred. Note that in both the present embodiment and the comparative example, the attitude control is performed by the feed-forward control. FIG. 7(G) shows the transition of the pitch angle θ P In FIG. 7(G), the solid line indicates the pitch angle θ P when the execution determination of the attitude control in the present embodiment is performed. In FIG. 7(G), the dashed-dotted 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]. P In FIG. 7(G), the dashed-dotted line indicates the pitch angle θ

[0077] As shown in Figure 7(A), the electric vehicle 100 is initially stationary. Then, as shown in Figure 7(B), the accelerator pedal is pressed down at time t1, and the accelerator opening A PO As the step increases, the total driving force TQ is generated and increases accordingly, as shown in Figure 7(C). As a result, as shown in Figure 7(A), 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 delays, torque response delays of the front motor 23 and rear motor 28, etc.

[0078] At this time, as shown in Figure 7(D), the estimated acceleration G est It begins to rise virtually without delay from time t1. Therefore, as shown in Figure 7(E), the estimated jerk J est This also occurs virtually without delay from time t1. Furthermore, as shown in Figure 7(D), the estimated acceleration G est The threshold TH is reached at time t2 between time t1 and time t4. G The above is assumed. Then, as shown in Figure 7(E), the estimated jerk J est At time t3 between time t2 and time t4, the threshold TH J The above values ​​are assumed. Therefore, at time t3, the estimated acceleration G est and estimated jerk J est However, each threshold TH G ,TH J This concludes the explanation. Therefore, as shown in Figure 7(F), in this embodiment (solid line), the attitude control flag FLG transitions from "0" (off) to "1" (on) at time t3, and attitude control is initiated.

[0079] On the other hand, as shown in Figure 7(D), the actual acceleration G act Due to the control delay, it begins to rise from time t4. Therefore, as shown in Figure 7(E), the actual jerk J act However, due to the control delay, it occurs from time t4. Also, as shown in Figure 7(D), the actual acceleration G act is the threshold TH GThe time t5 at which this occurs is later than time t4. And here, as shown in Figure 7(E), the actual jerk J act is the threshold TH J This is the result, and it will be further delayed. Therefore, at time t6, the actual acceleration G act and actual jerk J act However, each threshold TH G ,TH J This concludes the explanation. Therefore, as shown in Figure 7(F), in the comparative example (dash-dotted line), the attitude control flag FLG transitions from "0" (off) to "1" (on) at time t6, which is at least after time t4, and attitude control is initiated.

[0080] Therefore, comparing this embodiment with the comparative example, in this embodiment, the attitude control execution determination is completed at time t3, before acceleration G, etc., is actually generated in the electric vehicle 100, and attitude control is started when acceleration G, etc., is actually generated in the electric vehicle 100. In contrast, in the comparative example, the attitude control execution determination cannot be completed before time t4, when acceleration G, etc., is actually generated in the electric vehicle 100. For this reason, in the comparative example, a delay of at least the amount of control delay is unavoidable between the time acceleration G, etc., is actually generated in the electric vehicle 100 and the time attitude control is started.

[0081] As a result, as shown in Figure 7(G), in this embodiment (solid line), the pitch angle θ P After time t4, when the change occurs, quickly change the pitch rate Δ P While suppressing the (tilt), and the pitch angle θ P Target pitch angle θ P * It can be made to converge to the pitch angle θ. In other words, in this embodiment, P Attitude control can be activated from the very beginning of the fluctuations.

[0082] On the other hand, in the comparative example (dashed line), a steep pitch rate Δ occurs between time t4 and time t6 when attitude control begins. P pitch angle θ P The target pitch angle θ rises P *It approaches. Then, at time t6, attitude control is initiated, and the pitch angle θ P The target pitch angle θ P * It converges to this. Therefore, in the comparative example, most of the pitch angle θ is during the period from time t4 to time t6 when attitude control is not working. P This fluctuation occurs. In other words, in the comparative example, attitude control is practically not fast enough.

[0083] [Second Embodiment] In the first embodiment described above, the attitude control execution determination unit 47 determines the estimated acceleration G est and estimated jerk J est Based on this, the necessity of attitude control is determined, and the estimated acceleration G est Or estimated jerk J est The necessity of attitude control can also be determined based on any of the following. However, the specific configuration of the attitude control execution determination unit 47 for determining the necessity of attitude control is not limited to these. The attitude control execution determination unit 47 uses the estimated acceleration G est and / or estimated jerk J est In addition, actual acceleration G act Actual Jerk J act Based on either or both of these, it is possible to determine whether attitude control is necessary. In the following second embodiment, as an example, the attitude control execution determination unit 47 determines the estimated acceleration G est and estimated jerk J est The determination of whether attitude control is necessary based on actual acceleration G act and actual jerk J act This section describes a method for comprehensively determining the necessity of attitude control by combining it with the determination of whether attitude control is necessary based on the following factors.

[0084] Figure 8 is a block diagram showing the configuration of the attitude control execution determination unit 47 in the second embodiment. As shown in Figure 8, the attitude control execution determination unit 47 in 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, similar to those in the first embodiment. Furthermore, the attitude control execution determination unit 47 in the second embodiment includes a first pitch state determination unit 201 and a second pitch state determination unit 202 instead of the pitch state determination unit 55 in the first embodiment. In addition, the attitude control execution determination unit 47 in the second embodiment includes a flag setting unit 203 instead of the flag setting unit 56 in the first embodiment.

[0085] The first pitch state determination unit 201, similar to the pitch state determination unit 55 of the first embodiment, determines the estimated acceleration G est and estimated jerk J est Based on this, the pitch state (θ) that is predicted to occur P ,Δ P Depending on the situation, it is determined whether or not attitude control needs to be performed. Here, the first pitch state determination unit 201 determines whether or not attitude control is necessary in a simple or approximate manner, similar to the first embodiment. Specifically, the first pitch state determination unit 201 determines whether or not attitude control is necessary based on the estimated acceleration G est and estimated jerk J est Threshold TH for each G ,TH J This is set in advance. Then, the estimated acceleration G est is the threshold TH G The above (and below the upper limit UL), and the estimated jerk J est is the threshold TH J When the above conditions are met, the first pitch state determination unit 201 determines that it is necessary to perform attitude control (turn it on). Meanwhile, the estimated acceleration G est is the threshold TH G When it is smaller than or estimated jerk J est is the threshold TH J When the value is smaller than this, the first pitch state determination unit 201 determines that attitude control is not required.

[0086] The second pitch state determination unit 202 determines the actual acceleration G act and actual jerk J actThe second pitch state determination unit 202 obtains the actual pitch state (θ) and determines whether or not attitude control needs to be performed based on these. P ,Δ P The system determines whether attitude control is necessary based on the estimated acceleration G. est and estimated jerk J est Instead, actual acceleration G act and actual jerk J act Except for using the above, the second pitch state determination unit 202 can determine whether attitude control is necessary in the same way as the pitch state determination unit 55 of the first embodiment or the first pitch state determination unit 201.

[0087] Here, the second pitch state determination unit 202 uses the same simplified or approximate method as the specific necessity determination method performed by the first pitch state determination unit 201, to determine the actual acceleration G act and actual jerk J act Based on this, the necessity of attitude control is determined. That is, the second pitch state determination unit 202 determines the actual acceleration G act and actual jerk J act Threshold TH for each G ,TH J Set the actual acceleration G. act and actual jerk J act Threshold TH to set for G ,TH J This is the estimated acceleration G est and estimated jerk J est Threshold TH to set for G ,TH J The threshold values ​​can be different, but for simplicity, we will use the same value for the threshold TH. G ,TH J This is set. And the actual acceleration G act is the threshold TH G The above (and below the upper limit UL), and the actual jerk J act is the threshold TH J When the above conditions are met, the second pitch state determination unit 202 determines that it is necessary to perform (turn on) attitude control. Meanwhile, the actual acceleration G act is the threshold TH G When it is smaller than, or actual jerk Jact is the threshold TH J When the value is smaller than this, the second pitch state determination unit 202 determines that attitude control is not required.

[0088] The flag setting unit 203 sets the attitude control flag FLG based on the determination results of the gradient determination unit 54, the first pitch state determination unit 201, and the second pitch state determination unit 202.

[0089] Specifically, when the gradient determination unit 54 determines that attitude control is not required, the flag setting unit 203 sets the attitude control flag FLG to "0" (off), regardless of the determination results of the first pitch state determination unit 201 and the second pitch state determination unit 202.

[0090] On the other hand, when the gradient determination unit 54 determines that attitude control can be performed, the flag setting unit 203 sets the attitude control flag FLG based on the determination results of the first pitch state determination unit 201 and the second pitch state determination unit 202. Specifically, when the gradient determination unit 54 determines that attitude control can be performed and the first pitch state determination unit 201 determines that it is necessary to perform (turn on) attitude control, the flag setting unit 203 sets the attitude control flag FLG to "1" (on), regardless of the determination result of the second pitch state determination unit 202. Also, when the gradient determination unit 54 determines that attitude control can be performed, but the first pitch state determination unit 201 determines that it is not necessary to perform attitude control, the flag setting unit 203 sets the attitude control flag FLG to "1" (on) when the second pitch state determination unit 202 determines that it is necessary to perform (turn on) attitude control. If the gradient determination unit 54 determines that attitude control can be performed, but both the first pitch state determination unit 201 and the second pitch state determination unit 202 determine that attitude control is not required, the flag setting unit 203 sets the attitude control flag FLG to "0" (off).

[0091] In other words, when the gradient determination unit 54 determines that attitude control can be performed, the flag setting unit 203 sets the attitude control flag FLG to "1" (on) when either the first pitch state determination unit 201 or the second pitch state determination unit 202 determines that attitude control must be performed (on). Then, when the gradient determination unit 54 determines that attitude control can be performed, and both the first pitch state determination unit 201 and the second pitch state determination unit 202 determine that attitude control does not need to be performed, the attitude control flag FLG is set to "0" (off).

[0092] The following describes the operation of the on / off switch for attitude control in the electric vehicle 100 of the second embodiment, which is configured as described above.

[0093] Figure 9 is a flowchart showing the operation related to the on / off of attitude control for the electric vehicle 100 of the second embodiment. As shown in Figure 9, in step S20, the total driving force calculation unit 41 calculates the accelerator opening A PO The second pitch state determination unit 202 acquires the actual acceleration G act and actual jerk J act Next, in step S21, the total driving force calculation unit 41 calculates the total driving force TQ based on the accelerator opening APO, and the driving resistance calculation unit 51 calculates the driving resistance RL of the electric vehicle 100 based on the total driving force TQ and the vehicle speed VSP. Also in step S21, the acceleration estimation unit 52 estimates the acceleration G based on the driving resistance RL. est The jerk estimation unit 53 calculates the estimated acceleration G est Estimated jerk J using est Perform the calculation.

[0094] Subsequently, in step S22, the gradient determination unit 54 determines the road surface gradient φ LS The feasibility of attitude control is determined based on the road surface gradient φ. LS is the threshold TH LS Larger than, road surface gradient φ LS Therefore the crew's pitch angle θ PWhen it is not possible to sense the pitch angle θ and its variation, the process proceeds to step S28, where the attitude control is stopped or the stopped state of the attitude control is maintained. On the other hand, when the road surface gradient φ LS is less than or equal to the threshold value TH LS and the occupant can sense the pitch angle θ P and its variation, which may deteriorate the riding comfort of the electric vehicle 100, the process proceeds to step S23, and based on the predicted pitch state (θ P , Δ P ) or the actually occurring pitch state (θ P , Δ P the necessity of attitude control is determined.)

[0095] In step S23, the first pitch state determination unit 201 compares the estimated acceleration G est with the threshold value TH1] G When the estimated acceleration G est is greater than or equal to the threshold value 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 value TH J If the estimated jerk J est is greater than or equal to the threshold value TH J , that is, if both the estimated acceleration G est and the estimated jerk J est are greater than or equal to their respective threshold values TH G , TH J , it is determined that execution (on) of attitude control is necessary. Therefore, the process proceeds to step S27, where attitude control is executed or the execution of attitude control is maintained.

[0096] On the other hand, when in step S23 the estimated acceleration G est is less than the threshold value TH G , or when in step S24 the estimated jerk J est is less than the threshold value TH[[ID=

[53] ] J , the process proceeds to step S25, and the second pitch state determination unit 202 compares the actual acceleration G act with the threshold value TH G If the actual acceleration G act is greater than the threshold value THG If the above is true, proceed to step S26, and the second pitch state determination unit 202 further determines the actual jerk J act threshold TH J Compare it to this.

[0097] In step S25, the actual acceleration G act is the threshold TH G The above is true, and in step S26, the actual jerk J act is the threshold TH J When the above is true, it is determined that attitude control must be activated (turned on). Therefore, the process proceeds to step S27, where attitude control is activated or maintained. That is, estimated acceleration G est and estimated jerk J est Even if the determination based on this is that attitude control is not required, the actual acceleration G act and actual jerk J act If the determination based on this information indicates that attitude control needs to be activated (on), then attitude control will be turned on.

[0098] On the other hand, in step S25, the actual acceleration G act is the threshold TH G When it is smaller than or the actual jerk J in step S26 act is the threshold TH J When the value is smaller than this, it is determined that attitude control is not required. Therefore, the process proceeds to step S28, and attitude control is stopped, or the stopped state of attitude control is maintained. That is, estimated acceleration G est and estimated jerk J est Based on the results of the determination, it was determined that attitude control was not required, and the actual acceleration G act and actual jerk J act If the determination based on this process determines that posture control is not required, posture control will be turned off.

[0099] Thus, the estimated acceleration G est and estimated jerk J est A determination based on the actual acceleration G act and actual jerk J actBy combining the determination based on this and the determination of whether attitude control is necessary, at least the pitch angle θ P And when such fluctuations actually occur, attitude control will function reliably. For example, when there is a change in vehicle weight M or a change in air resistance due to the installation of aftermarket parts, the estimated acceleration G est and estimated jerk J est A significant calculation error occurs in the running resistance RL required for the calculation. Furthermore, the estimated acceleration G est and estimated jerk J est Before it is determined that attitude control needs to be performed (turned on) based on the pitch angle θ P And fluctuations in this may occur. In this case, as described above, the actual acceleration G act and actual jerk J act If the determination of whether attitude control is necessary is used in combination with this, then the pitch angle θ will be such that attitude control must be activated (turned on). P And when such fluctuations actually occur, attitude control can be activated.

[0100] [Third Embodiment] In the first and second embodiments described above, the estimated acceleration G est and estimated jerk J est The estimated acceleration G is calculated based on the running resistance RL, which is approximated by a quadratic function of the vehicle speed VSP. The coefficients A0, A1, and A2 in the approximation formula used to calculate the running resistance RL are predetermined by experimentation or simulation. However, the running resistance RL can change depending on the specific usage conditions of the electric vehicle 100. For example, when the vehicle weight M changes, or when the air resistance changes due to the installation of aftermarket parts, the running resistance RL of the electric vehicle 100 changes. In this way, when there is a significant change in the running resistance RL, the estimated acceleration G est and estimated jerk J estTo maintain the accuracy of the attitude control execution determination using this method, it is desirable to update the predetermined coefficients A0, A1, and A2 and accurately calculate the running resistance RL according to the specific usage conditions of the electric vehicle 100. In the following third embodiment, an example of updating the coefficients A0, A1, and A2 used in calculating the running resistance RL according to the specific usage conditions of the electric vehicle 100 will be described.

[0101] Figure 10 is a block diagram showing the configuration for updating the coefficients A0, A1, and A2 of the approximation formula used to calculate the running resistance RL. As shown in Figure 10, the controller 12 may include a coefficient update unit 301 in addition to the configuration of the first and / or second embodiment.

[0102] The coefficient update unit 301 includes a flat road determination unit 311, a steady-state driving determination unit 312, a first error calculation unit 313, a driving resistance storage unit 314, a second error calculation unit 315, and a coefficient update unit 316.

[0103] The flat road determination unit 311 determines the road surface gradient φ LS Based on this, it is determined whether the electric vehicle 100 is traveling on a flat road. That is, the flat road determination unit 311 determines whether the electric vehicle 100 is traveling in a state where gradient resistance is not included in the running resistance RL. Specifically, the flat road determination unit 311 determines whether the road surface gradient φ LS When the error is less than or equal to ±φ0 and close to zero, (-φ0≦φ LS If (≤ +φ0), it is determined that the electric vehicle 100 is traveling on a flat road.

[0104] The steady-state driving determination unit 312 determines whether the electric vehicle 100 is driving at a constant speed without accelerating or decelerating (so-called road driving). That is, the steady-state driving determination unit 312 determines whether the electric vehicle 100 is driving in a state where resistance due to acceleration and deceleration is not included in the driving resistance RL. In this embodiment, the steady-state driving determination unit 312 determines whether the actual acceleration G act Obtain the actual acceleration G act Based on this, it is determined whether steady-state driving is continuing. Specifically, the actual acceleration G act The error is less than or equal to ±G0 (-G0≦G) as predetermined.act When the condition is ≤ +G0), it is determined that the electric vehicle 100 is running at a steady pace.

[0105] The first error calculation unit 313 calculates the estimated acceleration G est and actual acceleration G act The first error G is the error of . err The (acceleration estimation error) is calculated. The first error calculation unit 313 calculates the estimated acceleration G from the acceleration estimation unit 52. est The first error calculation unit 313 obtains the estimated acceleration G in the same manner as the acceleration estimation unit 52. est The calculation may be performed. In this embodiment, the first error calculation unit 313 calculates the estimated acceleration G est From actual acceleration G at By subtracting this, the first error G err Perform the calculation.

[0106] Furthermore, the first error calculation unit 313 calculates the first error G err Based on this, the estimated acceleration G est The period during which a significant error occurs continuously (hereinafter, duration τ) err Specifically, the first error calculation unit 313 counts the calculated first error G. err A predetermined threshold TH err1 Compared to the first error G, err is the threshold TH err1 The time exceeding the specified duration τ err Let's assume that.

[0107] The running resistance memory unit 314 stores, at least temporarily, the running resistance RL when the electric vehicle 100 is running steadily on a flat road, in association with the vehicle speed VSP at that time. Specifically, the running resistance memory unit 314 stores the first error G during steady-state driving on a flat road. err is the threshold TH err1 The duration τ err However, if the result exceeds a predetermined threshold τ0, the total driving force TQ at that time is obtained. The driving resistance storage unit 314 then uses the obtained total driving force TQ to store the actual driving resistance RL during steady-state driving on a flat road (hereinafter referred to as actual driving resistance RL). act(This means) the vehicle speed is associated with the VSP and stored in memory.

[0108] The second error calculation unit 315 calculates the actual running resistance RL stored in the running resistance storage unit 314. act The second error RL is the error between the running resistance RL calculated by the running resistance calculation unit 51 and the second error RL. err Calculate the (running resistance error). Second error RL err The calculation is performed for each vehicle speed VSP. In addition, the second error calculation unit 315 calculates the second error RL err By calculating the variance and other statistical values, the second error RL is obtained. err Evaluate the variability.

[0109] The coefficient update unit 316 reads the actual running resistance RL act Based on this, the running resistance calculation unit 51 updates (calculates) all or part of the coefficients A0, A1, A2 used in calculating the running resistance RL. The coefficient update unit 316 updates the coefficients A0, A1, A2 used in calculating the running resistance RL by correcting the previously stored coefficients A0, A1, A2, or by calculating new coefficients A0, A1, A2 and replacing the previously stored coefficients A0, A1, A2.

[0110] In this embodiment, the coefficient update unit 316 stores at least three or more actual driving resistances RL in the driving resistance storage unit 314. act It remembers the second error RL err The variation is a predetermined threshold TH err2 The coefficient update unit 316 updates the coefficient A2 of the constant term when the following conditions are met. Specifically, the coefficient update unit 316 updates the second error RL err Based on this, the coefficient A2 of the constant term is corrected to update the coefficient A2 of the constant term. For example, the coefficient update unit 316 corrects the second error RL to the previous coefficient A2 of the constant term. err The coefficient A2 of the constant term is corrected by adding the average values ​​of the two values.

[0111] Furthermore, in this embodiment, the running resistance storage unit 314 stores at least three or more actual running resistances RL. act Although I remember it, the second error RL errThe variation is the threshold TH err2 When it is greater than RL, the coefficient update unit 316 updates the coefficients A0 and A1 of the second and first terms. Specifically, the coefficient update unit 316 updates the actual driving resistance RL act Based on this, the coefficients A0 and A1 of the quadratic and linear terms are newly calculated and updated. For example, the coefficient update unit 316 uses the previous value as the coefficient A2 of the constant term, and the actual driving resistance RL act By finding a quadratic regression curve based on this, the coefficients A0 and A1 of the new quadratic and linear terms are calculated.

[0112] Figure 11 is an explanatory diagram illustrating a specific manner in which the coefficients A0, A1, and A2 of the approximation formula used to calculate the running resistance RL are updated. In Figure 11, the datasets indicated by circles (○) in the legend represent the running resistance RL calculated using the pre-stored coefficients A0, A1, and A2 in the initial state of the electric vehicle 100. The datasets indicated by triangles (△) and squares (□) in the legend represent the running resistance RL stored by the running resistance storage unit 314 in independent driving scenes with different specific usage conditions for the electric vehicle 100.

[0113] As shown in Figure 11, when the running resistance RL, indicated by the triangle (△) legend, is obtained through steady-state driving on a flat road, the second error RL at each data point is obtained. err is, E 1A ,E 1B , and E 1C And these second errors RL err (=E 1A ,E 1B ,E 1C ) are all of roughly the same size, and their variation is threshold TH err2 The following applies. Therefore, the coefficient update unit 316 updates these second errors RL. err The average value, i.e., E 1A ,E 1B ,E 1CThe coefficient A2 of the constant term is updated by adding the average value of to the previous coefficient A2. This shifts the quadratic curve approximating the running resistance RL from a solid line to a dashed line. Therefore, updating the coefficient A2 of the constant term is preferable when running resistance components other than air resistance (such as rolling resistance) change due to changes in vehicle weight M, for example.

[0114] When steady-state driving on a flat road yields the driving resistance RL shown in the square (□) legend, the second error RL at each data point is obtained. err is, E 2A ,E 2B , and E 2C And these second errors RL err (=E 2A ,E 2B ,E 2C The size of each is different, and the variation is threshold TH err2 It is greater than [value]. Therefore, the coefficient update unit 316 updates the coefficients A0 and A1 of the quadratic and linear terms by obtaining a quadratic regression curve of the data points shown in the legend of the square (□) while maintaining the coefficient A2 of the constant term. This changes the shape of the quadratic curve approximating the running resistance RL from a solid line to a dashed line. Therefore, updating the coefficients A0 and A1 of the quadratic and linear terms is suitable when the air resistance of the electric vehicle 100 changes due to the installation or replacement of aftermarket parts, etc.

[0115] Figure 12 is a flowchart showing the process of updating the coefficients A0, A1, and A2 of the approximation formula used to calculate the running resistance RL. As shown in Figure 12, in step S30, the flat road determination unit 311 determines the road surface gradient φ LS Based on this, it is determined whether the electric vehicle 100 is traveling on a flat road. If it is determined that the electric vehicle 100 is traveling on a flat road, the process proceeds to step S31, where the steady-state driving determination unit 312 determines whether the electric vehicle 100 is traveling at a steady pace without accelerating or decelerating. If it is determined that the electric vehicle 100 is traveling at a steady pace, the process proceeds to step S32.

[0116] In step S32, the first error calculation unit 313 calculates the estimated acceleration G est and actual acceleration G act Based on this, the first error G err The first error G is calculated as well. err The duration τ for which there is a significant error err The duration τ is counted. Then, in step S33, err If the threshold τ0 becomes greater than or equal to the actual driving resistance RL, the process proceeds to step S34, where the driving resistance memory unit 314 stores the total driving force TQ at that time as the actual driving resistance RL. act It stores the vehicle speed in correspondence with the VSP.

[0117] Then, in step S35, the actual driving resistance RL act If there are three or more of these, in step S36, the second error calculation unit 315 calculates the second error RL err The calculation is performed, and the variability is evaluated.

[0118] Subsequently, in step S37, the coefficient update unit 316 updates the second error RL err The variation is the threshold TH err2 Determine whether the following is true or false. Then, determine the second error RL. err The variation is the threshold TH err2 If the following conditions are met, the process proceeds to step S38, and the coefficient update unit 316 updates the coefficient A2 of the constant term in the approximation formula used to calculate the running resistance RL. Meanwhile, the second error RL err The variation is the threshold TH err2 If it is greater than or equal to, the process proceeds to step S39, where the coefficient update unit 316 updates the coefficients A0 and A1 of the quadratic and first-order terms in the approximation formula used to calculate the running resistance RL.

[0119] As described above, by updating the coefficients A0, A1, and A2 in the approximation formula used to calculate the running resistance RL, even if the running resistance RL changes according to the specific usage conditions of the electric vehicle 100, the estimated acceleration G est and estimated jerk J est It is calculated accurately. As a result, the estimated acceleration G est and / or estimated jerk J estThe attitude control execution determination using this method is based on the actual pitch angle θ. P And this is done precisely before any fluctuations occur. For this reason, attitude control is performed at the actual pitch angle θ. P And it will be initiated promptly without delay in the occurrence of such fluctuations.

[0120] Furthermore, the third embodiment described above can be implemented in combination with either the first or second embodiment. In addition, in the third embodiment described above, the first error calculation unit 313 calculates the first error G which represents the estimation error of acceleration G. err The first error calculation unit 313 calculates the first error (J) representing the estimated error of the jerk J in a similar manner, but is not limited to this. err ) can be calculated. In this case, the subsequent processing is the first error (J) which represents the estimated error of the jerk J. err This can be done in the same manner as the third embodiment using ). In addition, the first error calculation unit 313 calculates an error (G) that represents the estimation error of acceleration G. err ) and the error (J) representing the estimated error of jerk J. err Both of these can be calculated as the first error. In this case, the subsequent processing is the error (G) representing the estimation error of acceleration G. err ) and the error (J) representing the estimated error of jerk J. err This can be done using both (G) and (G) to represent the estimation error of acceleration G. err ) persists above the threshold τ0, and / or the error (J) representing the estimated error of the jerk J continues. err When the actual running resistance RL continues to be above the threshold τ0, the running resistance storage unit 314 stores the actual running resistance RL. act It can be configured to store this information.

[0121] In the first, second, and third embodiments described above, the estimated acceleration G is used. est and estimated jerk J est Both are used to determine whether attitude control is being executed, but the estimated acceleration G est Or estimated jerk J est Only one of the two may be used for determining whether attitude control is performed. Similarly, in the second embodiment, the actual acceleration G act and actual jerk Jact Both are used to determine whether attitude control is being executed, but the actual acceleration G act Or actual jerk J act Only one of the two may be used for determining whether attitude control is being executed. This is also true when the third embodiment is combined with the second embodiment.

[0122] Furthermore, in the first, second, and third embodiments described above, attitude control is performed by feedforward control using the correction unit 48, but this is not limited to this. Attitude control is performed by the pitch angle θ that actually occurs. P or pitch rate Δ P Even when the control is performed by feedback control that provides feedback, it is preferable to perform attitude control execution determination by feedforward control, as in the first, second, and third embodiments described above.

[0123] As described above, the control methods for electric vehicles according to the first, second, and third embodiments are control methods for electric vehicles 100 that perform attitude control to control the attitude in the longitudinal direction by adjusting the driving force distribution of the front wheels 21 and rear wheels 26, which are the drive wheels. In this control method for electric vehicles 100, the total driving force TQ, which is the required driving force for the electric vehicle 100, is calculated based on the operation of the accelerator pedal, and the estimated acceleration G, which is an estimated value of the acceleration G that occurs when the electric vehicle 100 is driven with the total driving force TQ, is calculated based on the total driving force TQ. est , or estimated jerk J, which is an estimate of jerk J, the rate of change of acceleration G over time. est , is calculated. And the estimated acceleration G est Or estimated jerk J est Based on this, a determination is made to switch attitude control on or off.

[0124] Thus, the estimated acceleration G est Or estimated jerk J est Based on the feedforward control, when the on / off status of attitude control is determined, even if attitude control is turned off for reasons such as energy efficiency, the pitch angle θ PAnd attitude control can be initiated without delay before such fluctuations actually occur. In other words, when attitude control is turned on / off as needed by adjusting the driving force distribution, the delay in deciding whether to start attitude control can be reduced, and attitude control can be implemented in a timely manner. In particular, when attitude control is performed by feedforward control, the pitch angle θ P And attitude control functions before such fluctuations actually occur. Furthermore, even when attitude control is performed by feedback control, the control delay caused by the attitude control execution decision is reduced. Therefore, the delay in the start of attitude control can be minimized. Thus, as described above, estimated acceleration G est Or estimated jerk J est By determining whether to turn attitude control on or off using feedforward control based on this, attitude control can be performed by adjusting the driving force distribution while suppressing the deterioration of energy consumption. In other words, the deterioration of energy consumption due to attitude control is minimized, and the ride comfort of the electric vehicle 100 is improved.

[0125] In the electric vehicle control methods according to the first, second, and third embodiments described above, the estimated acceleration G is determined based on the total driving force TQ. est and estimated jerk J est The calculation is performed, and the estimated acceleration G est and estimated jerk J est Based on this, attitude control is switched on or off. In this way, the estimated acceleration G is used to determine whether to execute attitude control. est Estimated Jerk J est By using both, the accuracy of attitude control execution determination is improved. Also, the pitch state (θ) that the occupant can perceive is improved. P ,Δ P The posture control can be turned on at the appropriate timing according to the situation.

[0126] In the electric vehicle control methods according to the first, second, and third embodiments described above, in particular, the estimated acceleration G est However, the acceleration threshold (TH) is a predetermined threshold value for acceleration G. G ) and above, and the estimated jerk J estHowever, the jerk threshold (TH) is a predetermined threshold value for jerk J. J Attitude control is turned on when the pitch state (θ) is greater than or equal to this. Even with this simple method, the pitch state (θ) that the occupants can perceive can be determined. P ,Δ P The posture control can be turned on at the appropriate timing according to the situation.

[0127] In the control methods for electric vehicles according to the first, second, and third embodiments described above, attitude control is performed by feedforward control that corrects the driving force distribution based on the vehicle model. When attitude control is performed by feedforward control in this way, the estimated acceleration G est Or estimated jerk J est When attitude control is controlled on / off by the attitude control execution determination of feedforward control based on this, the pitch angle θ is particularly reliable. P Furthermore, the attitude control system functions before such fluctuations actually occur. In other words, it is particularly easy to achieve both the suppression of deterioration in energy consumption and the improvement of ride comfort through attitude control.

[0128] In the control methods for electric vehicles according to the first, second, and third embodiments described above, the gradient (φ) of the road surface on which the electric vehicle 100 travels is controlled. LS ) is obtained, and the gradient (φ LS ) and estimated acceleration G est Or estimated jerk J est Based on this, attitude control can be switched on or off. In this way, the road surface gradient φ LS According to the attitude control execution decision that takes this into account, the occupant's pitch angle θ P Furthermore, it is possible to keep attitude control off when driving on inclines where the fluctuations are difficult to perceive. As a result, the deterioration of energy consumption due to unnecessary attitude control is suppressed.

[0129] In the control methods for electric vehicles according to the first, second, and third embodiments described above, the gradient (φ LS ) is a predetermined gradient (TH LS If the estimated acceleration G is less than or equal to the following, estOr estimated jerk J est Based on this, the necessity of attitude control is determined, and the gradient (φ LS ) is a predetermined slope (TH LS If the pitch angle is greater than θ, attitude control is turned off. In other words, the occupant P Furthermore, when driving on steep inclines where the fluctuations are difficult to perceive, it is particularly reliable to keep the attitude control off. Therefore, the deterioration of energy consumption due to unnecessary attitude control is especially well suppressed.

[0130] In the control method for the electric vehicle according to the second embodiment described above, the actual acceleration G generated in the electric vehicle 100 is the actual acceleration G. act , or the actual jerk J, which is the time rate of change of the actual acceleration G that occurred in the electric vehicle 100. act This is obtained. And the estimated acceleration G est Or estimated jerk J est A determination based on, or actual acceleration G act Or actual jerk J act Attitude control is turned on when it is determined that attitude control is necessary based on any of the following criteria. act Or actual jerk J act Combining the determinations, the driving resistance RL contains a significant error depending on the specific usage conditions of the electric vehicle 100, and the estimated acceleration G est Or estimated jerk J est Even if the determination by this method is inaccurate, the actual pitch angle θ that occurred P When the pitch angle θ occurs, attitude control is performed. P And if such fluctuations actually occur, the attitude control will function reliably.

[0131] In the electric vehicle control methods according to the first, second, and third embodiments described above, the driving resistance RL of the electric vehicle 100 is calculated based on the vehicle speed VSP, and the estimated acceleration G is calculated based on the total driving force TQ and the driving resistance RL. est Or estimated jerk J est This is calculated. In this way, the estimated acceleration G is calculated based on the running resistance RL. estOr estimated jerk J est When this is calculated, the acceleration G is estimated accurately before the actual acceleration G occurs. est Or estimated jerk J est This allows for the calculation of [the desired outcome]. As a result, the accuracy of posture control execution decisions is improved.

[0132] In particular, in the control method for the electric vehicle according to the third embodiment described above, 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 in steady-state driving mode without accelerating or decelerating. Furthermore, the total driving force TQ when the electric vehicle 100 is in steady-state driving mode on a flat road is the actual driving resistance RL, which is the actual driving resistance. act It is stored as such. And the actual running resistance RL act Based on this, the coefficients A0, A1, and A2 used in calculating the running resistance RL are updated. By updating the coefficients A0, A1, and A2 used in calculating the running resistance RL in this way, the running resistance RL can be accurately calculated even if it changes according to the specific usage conditions of the electric vehicle 100. As a result, the accuracy of the attitude control execution determination is particularly improved.

[0133] Furthermore, in the control method for the electric vehicle according to the third embodiment described above, when the electric vehicle 100 is traveling steadily on a flat road, the estimated acceleration G est And the actual acceleration G that occurred in the electric vehicle 100 is the actual acceleration G. act And the acceleration estimation error (G) is the error between the two. err ) is calculated. Then, an acceleration estimation error (G) greater than or equal to a predetermined error (±G0) is calculated. err The actual running resistance RL when the condition continues for a predetermined time (τ0) or longer. act Based on this, the coefficients A0, A1, and A2 used in the calculation of the running resistance RL are updated. In this way, the actual acceleration G act For the estimated acceleration G est By updating the coefficients A0, A1, and A2 used in the calculation of the running resistance RL when it is certain that the calculation contains a significant error, unnecessary updates of the coefficients A0, A1, and A2 can be suppressed. As a result, the accuracy of the coefficients A0, A1, and A2 is improved, making it easier to maintain the accuracy of attitude control execution decisions.

[0134] Furthermore, in the control method for the electric vehicle according to the third embodiment described above, the calculated driving resistance RL and the actual driving resistance RL are used. act And the running resistance error (RL) is the error between the two. err ) is calculated, and this running resistance error (RL) err The variation of ) is a predetermined threshold TH err2 When the following conditions are met, the coefficient A2, which constitutes the constant term among the coefficients A0, A1, and A2 used in the calculation of the running resistance RL, is updated. In this way, the running resistance error (second error RL) err The variation of ) is the threshold TH err2 Updating coefficient A2 under the following conditions allows for accurate calculation of the running resistance RL in response to changes in factors of running resistance other than air resistance, such as rolling resistance. As a result, the accuracy of attitude control execution decisions is particularly well maintained when rolling resistance and other factors change.

[0135] Furthermore, in the control method for the electric vehicle according to the third embodiment described above, the calculated driving resistance RL and the actual driving resistance RL act And the running resistance error (RL) is the error between the two. err ) is calculated, and the running resistance error (RL) is calculated. err The variation of ) is a predetermined threshold TH err2 When it is greater than this, the coefficients A0 and A1, which constitute the term including the vehicle speed VSP among the coefficients A0, A1, and A2 used in the calculation of the driving resistance RL, are updated. In this way, the driving resistance error (second error RL) is calculated. err The variation of ) is the threshold TH err2 If coefficients A0 and A1 are updated when they are greater than the specified value, the driving resistance RL can be accurately calculated in response to the change in the air resistance of the electric vehicle 100. As a result, the accuracy of the attitude control execution decision is particularly well maintained when the air resistance changes.

[0136] The control devices for the electric vehicle according to the first, second, and third embodiments described above are control devices (controllers 12) for the electric vehicle 100 that perform attitude control to control the attitude in the longitudinal direction by adjusting the driving force distribution of the front wheels 21 and rear wheels 26, which are the drive wheels. This control device (controller 12) includes a total driving force calculation unit 41 that calculates the total driving force TQ, which is the required driving force for the electric vehicle 100, based on the operation of the accelerator pedal, and an estimated acceleration G, which is an estimated value of the acceleration G that occurs when the electric vehicle 100 is driven with the total driving force TQ, based on the total driving force TQ. est , or estimated jerk J, which is an estimate of jerk J, the rate of change of acceleration G over time. est The estimation unit (52,53) calculates the estimated acceleration G est Or estimated jerk J est The system includes an attitude control execution determination unit 47 that performs an attitude control execution determination to switch attitude control on or off based on the pitch angle θ. P Furthermore, attitude control can be initiated without delay, even before such fluctuations actually occur. Therefore, attitude control can be performed by adjusting the driving force distribution while suppressing the deterioration of energy consumption. In other words, the deterioration of energy consumption due to attitude control is minimized, and the ride comfort of the electric vehicle 100 is improved.

[0137] Furthermore, the control programs for the electric vehicle 100 according to the first, second, and third embodiments described above include: a total driving force calculation unit 41 that calculates the total driving force TQ, which is the required driving force for the electric vehicle 100, based on the operation of the accelerator pedal; and an estimated acceleration G, which is an estimated value of the acceleration G that occurs when the electric vehicle 100 is driven with the total driving force TQ, based on the total driving force TQ. est , or estimated jerk J, which is an estimate of jerk J, the rate of change of acceleration G over time. est Estimation unit (52,53) that calculates the estimated acceleration G est Or estimated jerk J estBased on this, it functions as a posture control execution determination unit 47 that performs posture control execution determination to switch posture control on or off.

[0138] Although embodiments of the present invention have been described above, the configurations described in the above embodiments and each of the modifications represent only a part of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

Claims

1. A control method for an electric vehicle that performs attitude control to control the vehicle's posture in the longitudinal direction by adjusting the distribution of driving force between the front and rear wheels, which are the drive wheels, Based on the operation of the accelerator pedal, the total driving force, which is the required driving force for the electric vehicle, is calculated. Based on the total driving force, the estimated acceleration, which is an estimated value of the acceleration that occurs when the electric vehicle is driven by the total driving force, and the estimated jerk, which is an estimated value of the jerk, which is the rate of change of the acceleration over time, are calculated. The gradient of the road surface on which the electric vehicle travels is obtained, If the gradient is less than or equal to a predetermined gradient, and the estimated acceleration is greater than or equal to an acceleration threshold which is a predetermined threshold for the acceleration, and the estimated jerk is greater than or equal to a jerk threshold which is a predetermined threshold for the jerk, then the attitude control is turned on. If the gradient is greater than the predetermined gradient, the attitude control is turned off. A method for controlling electric vehicles.

2. A control method for an electric vehicle that performs attitude control to control the vehicle's posture in the longitudinal direction by adjusting the distribution of driving force between the front and rear wheels, which are the drive wheels, Based on the operation of the accelerator pedal, the total driving force, which is the required driving force for the electric vehicle, is calculated. Based on the vehicle speed, the running resistance of the electric vehicle is calculated, Based on the total driving force and the running resistance, the estimated acceleration, which is an estimated value of the acceleration that occurs when the electric vehicle is driven by the total driving force, and the estimated jerk, which is an estimated value of the jerk, which is the rate of change of the acceleration over time, are calculated. When the estimated acceleration is greater than or equal to an acceleration threshold, which is a predetermined threshold for the acceleration, and the estimated jerk is greater than or equal to a jerk threshold, which is a predetermined threshold for the jerk, the attitude control is turned on. Determine whether the road surface on which the electric vehicle travels is flat or not. Determine whether the electric vehicle is in a steady state without accelerating or decelerating, The total driving force when the electric vehicle is running steadily on the flat road is stored as the actual driving resistance, which is the actual driving resistance. Based on the actual running resistance, the coefficient used in calculating the running resistance is updated. A method for controlling electric vehicles.

3. A method for controlling an electric vehicle according to claim 1 or 2, The attitude control is performed by feedforward control that corrects the power distribution based on the vehicle model. A method for controlling electric vehicles.

4. A control method for an electric vehicle according to claim 2, When the electric vehicle is traveling steadily on the flat road, the acceleration estimation error, which is the difference between the estimated acceleration and the actual acceleration that occurred in the electric vehicle, is calculated. Based on the actual running resistance when the acceleration estimation error, which is greater than or equal to a predetermined error, persists for a predetermined time or longer, the coefficient used in calculating the running resistance is updated. A method for controlling electric vehicles.

5. A control method for an electric vehicle according to claim 4, The running resistance error, which is the difference between the calculated running resistance and the actual running resistance, is calculated. When the variation in the aforementioned running resistance error is below a predetermined threshold, the coefficients that constitute the constant term among the coefficients used in the calculation of the running resistance are updated. A method for controlling electric vehicles.

6. A control method for an electric vehicle according to claim 5, The running resistance error, which is the difference between the calculated running resistance and the actual running resistance, is calculated. When the variation in the aforementioned driving resistance error is greater than a predetermined threshold, the coefficients that constitute the term including the vehicle speed among the coefficients used in the calculation of the driving resistance are updated. A method for controlling electric vehicles.

7. A control device for an electric vehicle that performs attitude control to control the vehicle's posture in the longitudinal direction by adjusting the distribution of driving force between the front and rear wheels, which are the drive wheels, A total driving force calculation unit calculates the total driving force, which is the required driving force for the electric vehicle, based on the operation of the accelerator pedal, An estimation unit calculates, based on the total driving force, an estimated acceleration, which is an estimated value of the acceleration generated when the electric vehicle is driven by the total driving force, and an estimated jerk, which is an estimated value of the jerk, which is the rate of change of the acceleration over time. A posture control execution determination unit that, when the gradient of the road surface on which the electric vehicle travels is less than or equal to a predetermined gradient, the estimated acceleration is greater than or equal to an acceleration threshold which is a predetermined threshold for the acceleration, and the estimated jerk is greater than or equal to a jerk threshold which is a predetermined threshold for the jerk, turns on the posture control, and turns off the posture control when the gradient is greater than the predetermined gradient, A control device for electric vehicles, equipped with the following features.

8. A control device for an electric vehicle that performs attitude control to control the vehicle's posture in the longitudinal direction by adjusting the distribution of driving force between the front and rear wheels, which are the drive wheels, A total driving force calculation unit calculates the total driving force, which is the required driving force for the electric vehicle, based on the operation of the accelerator pedal, A running resistance calculation unit that calculates the running resistance of the electric vehicle based on the vehicle speed, An estimation unit calculates, based on the total driving force and the running resistance, an estimated acceleration, which is an estimated value of the acceleration generated when the electric vehicle is driven by the total driving force, and an estimated jerk, which is an estimated value of the jerk, which is the rate of change of the acceleration over time. A posture control execution determination unit that turns on the posture control when the estimated acceleration is greater than or equal to an acceleration threshold which is a predetermined threshold for the acceleration, and the estimated jerk is greater than or equal to a jerk threshold which is a predetermined threshold for the jerk, Equipped with, The attitude control execution determination unit is: Determine whether the road surface on which the electric vehicle travels is flat or not. Determine whether the electric vehicle is in a steady state without accelerating or decelerating, The total driving force when the electric vehicle is running steadily on the flat road is stored as the actual driving resistance, which is the actual driving resistance. Based on the actual running resistance, the coefficient used in calculating the running resistance is updated. Control device for electric vehicles.

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