JP2009184522A - Vehicular vibration suppression device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular control device inhibiting energy efficiency from being reduced when suppressing vehicular vertical vibration. <P>SOLUTION: The vehicular vibration suppression device includes: front and rear wheels attached to a vehicle body via a suspension device; and a control device for respectively controlling the driving and braking force of the front wheels and the driving and braking force of the rear wheels. The vehicular vibration suppression device implements either pitching suppression control for suppressing pitching movements of the vehicle body, or bouncing suppression control for suppressing bouncing movements of the vehicle body by applying the driving force or the braking force to the front wheels and applying the driving force or the braking force to the rear wheels. A determination means (step S2) for determining whether the braking force should be applied to the front wheels or the rear wheels, and a prohibition means (step S3) for prohibiting the suppression control determined to apply the braking force to the front wheels or the rear wheels, are provided in at least either one of the bouncing suppression control and the pitching suppression control. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle vibration suppression device capable of attaching front wheels and rear wheels to a vehicle body and changing the distribution of driving force transmitted to the front wheels and rear wheels.

  A vehicle such as a passenger car or a truck has a configuration in which wheels are attached to a vehicle body via a suspension device, and an impact input via the wheels from a road surface is absorbed by a spring provided in the suspension device and is mitigated. It is known that the vehicle body vibrates in the vertical direction when the load supported by the spring of the suspension device, that is, the “sprung load” changes. Specifically, bouncing in which the front and rear of the vehicle body vibrate in the vertical direction with the same phase and pitching in which the front and rear of the vehicle body vibrate in the vertical direction with opposite (reverse) phases occur. An example of a traveling device for eliminating such inconvenience is described in Patent Document 1. In the vehicle described in Patent Document 1, a front wheel and a rear wheel are respectively attached to a vehicle body with a suspension device interposed therebetween. The front wheel motor is disposed in the front wheel, and the rear wheel motor is disposed in the rear wheel. Furthermore, a power source is mounted on the vehicle body, and the power source is connected to each electric motor via an inverter. Furthermore, it describes that the power of the power source can be supplied to the electric motor, and the electric motor can be regeneratively controlled to control the generated power to be charged to the power source.

  And in patent document 1, when suppressing bouncing of a vehicle, the front wheel is solved by solving the equation of motion in the vertical direction on the spring of the vehicle under the condition that the fluctuation of the sprung load of the suspension device becomes smaller than a predetermined threshold value. The distribution ratio of the driving force between the vehicle and the rear wheel is obtained. That is, the driving force of the front wheels and the driving force of the rear wheels necessary for suppressing bouncing are obtained. On the other hand, in Patent Document 1, when suppressing the pitching of the vehicle, the front wheel and the rear wheel are solved by solving the equation of motion of the pitching rotation on the spring of the vehicle under the condition that the differential value of the pitch rate is smaller than a predetermined threshold value. The distribution ratio of the driving force between That is, the driving force of the front wheels and the driving force of the rear wheels necessary for suppressing bouncing are obtained. Patent Document 1 also describes a power train configured to distribute engine output to front wheels and rear wheels via a driving force distribution device. In a vehicle having this power train, the same as described above. Thus, it is described that the distribution ratio of the driving force transmitted to the front wheels and the rear wheels is determined.

JP 2007-161032 A

  However, when the electric motor is controlled to suppress bouncing or pitching of the vehicle by the technique described in Patent Document 1, a negative driving force (braking force) may be applied to the front wheels or the rear wheels, which is supplied to the electric motor. There is a possibility that the efficiency of converting the generated energy into the driving force is reduced. Further, in the power train described in Patent Document 1 and having an engine, there is a possibility that the efficiency of converting the heat energy when the fuel supplied to the engine is burned into the driving force of the wheels is reduced. . That is, there is a possibility that the fuel consumption may be reduced.

  The present invention has been made against the background of the above circumstances, and in the case of suppressing the vibration of the vehicle body in the vertical direction, the vibration of the vehicle capable of suppressing a decrease in the efficiency of converting energy into driving force. An object is to provide a suppression device.

  In order to solve the above problems, the invention of claim 1 is directed to a front wheel and a rear wheel arranged at different positions in the longitudinal direction of the vehicle body, and the front wheel and the rear wheel are attached to the vehicle body, and the front wheel and the rear wheel are mounted. A suspension device that can be moved relative to the vehicle body in the vertical direction independently; and a control device that independently controls the driving force and braking force of the front wheels and the braking force and driving force of the rear wheels. And detecting the presence or absence of bouncing in which the front and rear of the vehicle body vibrate in the vertical direction with the same phase and the presence or absence of pitching in which the front and rear of the vehicle body are vibrated in the vertical direction with opposite phases. When the bouncing or the pitching occurs, the driving force or the braking force is applied to the front wheel, and the driving force or the braking force is applied to the rear wheel to suppress the pitching. In a vehicle vibration suppression device that performs either pitching suppression control or bouncing suppression control that suppresses bouncing, a braking force is applied to the front wheel or the rear wheel in at least one of the bouncing suppression control or pitching suppression control. A determination means for determining whether or not to suppress the suppression control determined to give a braking force to the front wheel or the rear wheel, and the suppression determined to give a driving force to the front wheel or the rear wheel And a prohibiting means for permitting control to be performed.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect, the prohibiting means prohibits one of the suppression controls and permits the other suppression control in the vertical direction of the vehicle body in the permitted control. Determine the amount of vibration, determine whether the amount of vibration is less than or equal to a predetermined value, and if the amount of vibration is less than or equal to a predetermined value, It is characterized by including means for performing a predetermined predetermined time and then performing permitted suppression control.

  According to a third aspect of the present invention, in addition to the configuration of the second aspect, the prohibiting means sets the predetermined time relatively longer as the vibration amount in the vertical direction of the vehicle body in the permitted suppression control is relatively smaller. It is characterized by including the means to do.

  According to a fourth aspect of the present invention, in addition to the structure of any one of the first to third aspects, an electric motor that applies a driving force and a braking force to at least one of the front wheel and the rear wheel is provided. is there.

  According to a fifth aspect of the invention, in addition to the configuration of the fourth aspect, the electric motor is supported by the vehicle body together with the front wheel or the rear wheel via the suspension device.

  According to the first aspect of the present invention, it is prohibited to perform the suppression control in which the braking force is applied to the front wheels or the rear wheels in the bouncing suppression control or the pitching suppression control. Therefore, it is possible to suppress a decrease in efficiency in converting energy into driving force.

  According to the invention of claim 2, in addition to obtaining the same effect as that of the invention of claim 1, in the case where the vibration suppressed by the permitted control is relatively small, the vibration of the prohibited control is temporarily Can be suppressed. Therefore, vibrations that should be suppressed by the prohibited control can be suppressed.

  According to the invention of claim 3, in addition to obtaining the same effect as that of the invention of claim 2, the time for which the prohibited control is temporarily performed becomes longer as the vibration of the permitted control is relatively small. can do. Therefore, the two suppression controls can be executed more appropriately according to the magnitude of the vibration to be suppressed.

  According to the invention of claim 4, in addition to obtaining the same effect as that of any of the inventions of claims 1 to 3, bouncing or pitching can be suppressed by controlling the electric motor.

  According to the invention of claim 5, the same effect as that of the invention of claim 4 can be obtained.

  The vehicle in the present invention includes a passenger car, a truck, a bus and the like. In the present invention, the front of the vehicle body is a direction along the traveling direction of the vehicle and means the front of the center of gravity of the vehicle body, and the rear of the vehicle body is a direction along the traveling direction of the vehicle and from the center of gravity of the vehicle body. Means backward. Note that the center of gravity of the vehicle body itself can be handled as front or rear. The suspension device according to the present invention is a mechanism for attaching a wheel to a vehicle body, and may be either an independent suspension device in which each wheel can operate independently in the vertical direction or an axle suspension device to which left and right wheels are connected. The control device according to the present invention includes a driving force source capable of applying a braking force and a positive driving force to the wheels. The driving force source includes an electric motor, an engine, a hydraulic motor, and a braking device. The electric motor can convert electric energy into kinetic energy, give a driving force to the wheel, and apply a braking force to the wheel by performing regenerative control.

  In addition, the engine can convert the heat energy when the fuel is burned into kinetic energy and give driving force to the wheels. Further, it is possible to apply a braking force to the wheels by controlling the engine braking force. Furthermore, in a hydraulic motor, it is possible to give a driving force to a wheel by converting the fluid energy of oil into the kinetic energy of a rotating shaft. In this way, it is possible to apply braking force and driving force to the wheels using a plurality of types of driving force sources having different power generation principles. And it is possible to give a braking force to a wheel by carrying out regenerative control of an electric motor.

  Furthermore, the control device according to the present invention includes a braking device that cannot apply a positive driving force to the wheels in addition to the above-described driving force source. This braking device includes a friction braking device that applies a braking force to a wheel by a friction force, and an actuator that controls the friction braking device. The braking force is a force that tries to stop the rotation of the wheel. The braking device includes an electromagnetic braking device that applies a braking force to the wheel by an electromagnetic force, and an actuator that controls the electromagnetic braking device. Further, the vehicle according to the present invention is configured to be able to change the distribution ratio of the driving force transmitted to the front wheels and the rear wheels. The vertical direction in the present invention means the direction of action of gravity, that is, the vertical direction. The vehicle body in the present invention may be either a frameless structure without a frame or a monocoque structure vehicle body having a frame. Furthermore, the vehicle according to the present invention transmits power to the rear wheels and a power train having a configuration in which a driving force source that transmits power to the front wheels and the rear wheels is shared, or a driving force source that transmits power to the front wheels. The driving force source may be any of the power trains configured separately.

  Next, an example of a vehicle which is a specific example of the present invention will be described with reference to the drawings. FIG. 2 is a schematic plan view of the vehicle 1, and FIG. 3 is a schematic side view of the vehicle 1. In FIG. 2, a right front wheel 4 is attached to a vehicle body 2 of a vehicle 1 with a suspension device 3 interposed, and a left front wheel 6 is attached with a suspension device 5 interposed. For the sake of convenience, the right front wheel 4 and the left front wheel 6 may be simply referred to as “front wheels”. Further, a right rear wheel 8 is attached with a suspension device 7 interposed, and a left rear wheel 10 is attached with a suspension device 9 interposed. For the sake of convenience, the right rear wheel 8 and the left rear wheel 10 may be simply referred to as “rear wheels”. The right front wheel 4 and the left front wheel 6 are disposed in front of the right rear wheel 8 and the left rear wheel 10 in the front-rear direction of the vehicle body 2. Here, the front-rear direction of the vehicle body 1 represents a position based on the center of gravity G1 of the vehicle body 1 when the vehicle 1 travels forward. The front side of the center of gravity G1 is “front”, and the center of gravity G1. The rear is also “rear”. “Right” and “left” refer to the direction in which the vehicle 1 moves forward (arrow X1 direction), the right half is “right” and the left half is “left” with respect to the center of the vehicle body 1. It is.

  The right front wheel 4 is configured by attaching a tire to a wheel, and the tire is grounded. An electric motor 11 is disposed inside the cylindrical portion of the wheel of the right front wheel 4. That is, the electric motor 11 is also indirectly supported by the suspension device 3. The left front wheel 6 is configured by attaching a tire to a wheel, and the tire is grounded. An electric motor 12 is disposed inside the cylindrical portion of the wheel of the left front wheel 6. That is, the electric motor 12 is also indirectly supported by the suspension device 5. The right rear wheel 8 is configured by attaching a tire to the wheel, and the tire is grounded. An electric motor 13 is disposed inside the cylindrical portion of the wheel of the right rear wheel 8. That is, the electric motor 13 is indirectly supported by the suspension device 7. The left rear wheel 10 is configured by attaching a tire to a wheel, and the tire is grounded. An electric motor 14 is disposed inside the cylindrical portion of the wheel of the left rear wheel 10. That is, the electric motor 14 is indirectly supported by the suspension device 9. As described above, the vehicle 1 shown in FIG. 2 is a four-wheel drive vehicle having a configuration in which an electric motor as a driving force source is connected to a front wheel and a rear wheel so that power can be transmitted.

  In this specific example, independent suspension devices are used as the suspension devices 3, 5, 7, and 9. With the independent suspension device, each wheel is independently attached to the vehicle body so as to be movable in the vertical direction. As the suspension devices 3 and 5, for example, a strut type or double wishbone type can be used. The strut-type suspension device includes a lower arm to which wheels and an electric motor are attached, a shock absorber interposed between the lower arm and the vehicle body 2, and a spring attached to the shock absorber. Further, the lower arm is configured to be swingable with the swing shaft ORf as a fulcrum. In the double wishbone type suspension device, a lower arm and an upper arm are swingably attached to a vehicle body, and wheels and an electric motor are supported by the lower arm and the upper arm. Further, the lower arm and the vehicle body are connected by a shock absorber, and a spring is interposed between the lower arm and the vehicle body.

  On the other hand, as the suspension devices 7 and 9, for example, a semi-trailing arm type can be used. The semi-trailing arm type suspension device includes a lower arm to which wheels and an electric motor are attached, a shock absorber interposed between the lower arm and the vehicle body, and a spring interposed between the lower arm and the vehicle body. It is. Further, the lower arm is attached to the vehicle body 2 so as to be swingable about the swing axis ORr.

  Furthermore, each of the electric motors 11, 12, 13, and 14 is a motor generator that has both a function of converting electric energy into kinetic energy and a function of converting kinetic energy into electric energy. Further, a power source 16 is connected to the motors 11, 12, 13, 14 through an inverter 15. As the power supply 16, a secondary battery capable of being charged and discharged, for example, a battery or a capacitor can be used. In addition to the secondary battery, a fuel cell can also be used. Furthermore, a braking device for applying a braking force to each wheel is provided. In this specific example, a braking device 18 that applies braking force to the right front wheel 4, a braking device 19 that applies braking force to the left front wheel 6, a braking device 20 that applies braking force to the right rear wheel 8, and the left rear wheel 10 A braking device 21 for providing a braking force is provided.

  Each wheel is provided with a rotor that rotates integrally with the wheel, and each braking device has a caliper that sandwiches each rotor and applies a braking force to each wheel separately. Each caliper has a pair of brake pads and a hydraulic chamber that controls the clamping force between the brake pads, and a known structure in which the braking force applied to the wheels is controlled by controlling the hydraulic pressure of the hydraulic chamber. have. That is, each braking device 18, 19, 20, 21 is a hydraulically controlled braking device. And the hydraulic control apparatus 22 is provided in the vehicle 1 as an actuator which controls the hydraulic pressure of the hydraulic chamber of each brake device. The hydraulic control device 22 is a known device having a hydraulic circuit and various valves.

  Next, the control system of the vehicle 1 will be described. An electronic control device 23 is provided as a controller for controlling a system mounted on the vehicle 1. Here, the system means each electric motor and inverter 15, each braking device and hydraulic control device 22. Further, the vehicle 1 includes “shift position, acceleration request in the vehicle 1, deceleration request (braking request) in the vehicle 1, vehicle speed, rotational speed of the motors 11, 12, 13, 14, vertical load applied to the front wheels, rear A detection device that detects a vertical load applied to the wheel or the like is provided. The detection device has at least one of a sensor or a switch, and signals from these switch and sensor are input to the electronic control device 23. The shift position is for detecting an operation state of a shift position selection device operated by an occupant of the vehicle 1. For example, a drive (D) position, a reverse (R) position, a parking (P) position, and the like are detected. The

  The drive position is a shift position that is selected when generating a driving force in a direction for moving the vehicle 1 forward. The reverse position is a shift position that is selected when a driving force in a direction that causes the vehicle 1 to move backward (reverse) is generated. The parking position is a shift position that is selected when the vehicle 1 is stopped. Moreover, the sensor which detects the acceleration request | requirement in the vehicle 1 detects the operation state of the accelerator pedal operated with a leg | foot, ie, the accelerator opening, for example. Moreover, the sensor which detects the deceleration request | requirement in the vehicle 1 detects the depression amount or depression speed of the brake pedal operated, for example with a leg | foot.

  Further, the vehicle 1 is provided with a vibration detection sensor 24 that detects vibration in the vertical direction of the vehicle body 2. As the vibration detection sensor 24, it is possible to use a sensor that separately detects a vertical stroke change of a shock absorber provided in each suspension device and outputs a signal. The vibration detection sensor 24 detects the stroke of the shock absorber, and separately detects the vertical acceleration at the front of the vehicle body 2 and the vertical acceleration at the rear of the vehicle body 2 and outputs a signal. An acceleration sensor can be used. A signal from the vibration detection sensor 24 is input to the electronic control unit 23. Further, the electronic control unit 23 stores data and a map for controlling the rotation speed and torque of each of the electric motors 11, 12, 13, 14 and the braking force applied to each wheel from each braking device. Data to be controlled and a map are stored.

  Next, control of driving force in the vehicle 1 will be described. For example, when the drive position is selected and the accelerator pedal is depressed, the total driving force in the vehicle 1 is obtained based on the vehicle speed and the accelerator opening. Based on this total driving force, the total required power in each of the electric motors 11, 12, 13, and 14 is obtained. This total required power is a power that should be borne by all four motors, and a map for obtaining the total required power from the total driving force is stored in advance in the electronic control unit 23. In addition, when the total required power corresponding to the total driving force is borne by each motor, the distribution ratio of the driving force between the front wheels and the rear wheels is determined and transmitted to the front wheels based on the distribution ratio of the driving force. The power to be transmitted and the power transmitted to the rear wheel are controlled. In order to perform this control, for example, the driving force between the front wheel and the rear wheel is based on the distribution ratio between the load applied to the right front wheel 4 and the left front wheel 6 and the load applied to the right rear wheel 8 and the left rear wheel 10. A map for determining the distribution ratio is stored in the electronic control unit 23.

  In this way, when the vehicle 1 is traveling forward, the vehicle body 2 may vibrate in the vertical direction due to road surface unevenness. In this specific example, control for suppressing vibration of the vehicle body 2 in the vertical direction can be performed. Control for suppressing vibration of the vehicle body 2 The vibration modes of the vehicle body 2 include bouncing and pitching. First, bouncing will be described. Bouncing means that the front and rear of the vehicle body 2 vibrate in the vertical direction with the same phase. In this specific example, the equation of motion (formula (1) to formula (4)) in the vertical direction on the spring of the vehicle 1 is solved under the condition that the fluctuation of the sprung load of each suspension device becomes smaller than a predetermined threshold. The vehicle body 2 is prevented from bouncing by obtaining the driving force distribution ratio between the front wheels and the rear wheels.

  The following equation (1) shows that the load on the springs of the suspension devices 3 and 5 for the front wheels and the reaction force component of the driving force of the front wheels that acts on the springs of the suspension devices 3 and 5 for the front wheels, This is a first relationship determined by the total driving force of the vehicle 1. Further, the relationship shown in the equation (2) is that the reaction force between the load on the springs of the suspension devices 7 and 9 for the rear wheels and the driving force of the rear wheels acting on the springs of the suspension devices 7 and 9 for the rear wheels This is a second relationship determined by the component and the total driving force of the vehicle 1.

Wf = Wf0−h * F / L + Ff1 (1)
Wr = Wr0 + h * F / L-Fr1 (2)
Ff1 = Ff * tan θf (3)
Fr1 = Fr * tan θr (4)

  Here, Wf is a load (front side sprung load) supported by the springs of the suspension devices 3 and 5 for the front wheels, and Wr is a load (rear side) supported by the springs of the suspension devices 7 and 9 for the rear wheels. Wf0 is a front sprung static load, and Wr0 is a rear sprung static load. Here, the “sprung load” is a load supported by the suspension device when the vehicle 1 travels, and the “sprung static load” is supported by the suspension device when the vehicle 1 is stopped. Load. Further, h is a height (center of gravity height) from the road surface Ro to the center of gravity G1 of the vehicle body 2, and L is a front axle (rotation center of the front wheel) Zf and a rear axle (rotation center of the rear wheel) Zr. Is the distance between the axes (wheelbase). Lf is a horizontal distance from the center of gravity G1 to the front axle Zf, and Lr is a horizontal distance from the center of gravity G1 to the rear axle Zr. The rotation center of the front wheel and the rotation center of the rear wheel are the rotation centers along the front-rear direction of the vehicle 1 and in a vertical plane.

  Further, Ff1 is a reaction force component (front drive reaction force component) of the driving force of the front wheels that acts on the springs of the suspension devices 3 and 5, and Fr1 is a rear wheel that acts on the springs of the suspension devices 7 and 9. , Ff is the driving force for the front wheels, Fr is the driving force for the rear wheels, and F is the total driving force in the vehicle 1. . Θf is the instantaneous rotation center angle of the suspension devices 3 and 5 for the front wheels, and θr is the instantaneous rotation center angle of the suspension devices 7 and 9 for the rear wheels. The instantaneous rotation center angle θf is an angle between a line segment connecting the swing axis ORf and the ground contact point of the front wheel and the road surface Ro when the front wheel swings in the vertical direction about the swing axis ORf. is there. The instantaneous rotation center angle θr is defined between the road surface Ro and a line segment connecting the swing axis ORr and the ground contact point of the rear wheel when the rear wheel swings in the vertical direction about the swing axis ORr. Is an angle.

Then, the equations (1) to (4) are solved under the condition that the fluctuation of the front spring load and the fluctuation of the rear spring load are smaller than a predetermined threshold value. Specifically, the sum of loads on the springs of the suspension devices 3, 5, 7, and 9 while the vehicle 1 is traveling and the springs of the suspension devices 3, 5, 7, and 9 when the vehicle 1 is stationary (stopped). The condition that the difference from the above sum of static loads is smaller than a predetermined threshold (ΔW) (| (Wf + Wr) − (Wf0 + Wfr) | <ΔW))
Solve with. In this specific example, a predetermined threshold value ΔW = 0 is set to “0”. That is, it is solved under the condition that the fluctuation of the sprung load of the suspension devices 3, 5, 7, 9 is smaller than a predetermined threshold value. Specifically, the sum of the loads on the springs of the suspension devices 3, 5, 7, 9 while the vehicle 1 is traveling is the static load on the springs of the suspension devices 3, 5, 7, 9 when the vehicle 1 is stationary. The above equations (1) to (4) are solved under the condition (Wf + Wr = Wf0 + Wfr) that is equal to the sum of the above. Then, the relationship of Formula (5) is materialized between the driving force of the front wheel and the driving force of the rear wheel.
Fr = (tan θf / tan θr) * Ff (5)
Then, with respect to the total driving force F obtained based on the vehicle speed and the accelerator opening, the front wheel driving force Ff and the rear wheel driving force fr are F = Ff + Fr.
If the distribution ratio between the driving force of the front wheels and the driving force of the rear wheels is controlled so as to satisfy this relationship, bouncing of the vehicle body 2 can be suppressed.

  Next, the pitching will be described. The pitching is that the front and rear of the vehicle 1 vibrate in opposite phases. In order to suppress this pitching, the equation of motion of pitching rotation of the vehicle body 2 on the spring of the suspension device (formula (6) to formula (10)), the differential value of the pitch rate (rotation speed of the pitch angle) is a predetermined threshold value. Solve under conditions smaller than ΔP ″. In this specific example, the above formulas (6) to (10) are solved under the condition that the predetermined threshold ΔP ″ is 0 “zero”. Thereby, the distribution ratio of the driving force between the front wheels and the rear wheels is obtained. It should be noted that the relationship shown in Expression (7) is that the load supported by the spring of the front wheel suspension, the reaction force component of the driving force of the front wheel acting on the spring of the front wheel suspension, and the total driving force of the vehicle The first relationship determined by Further, the relationship shown in the equation (8) is that the load supported by the spring of the rear wheel suspension, the reaction force component of the driving force of the rear wheel acting on the spring of the rear wheel suspension, and the total vehicle This is the second relationship determined by the driving force.

IpP ″ = WrLr−WfLf (6)
Wf = Wf0−h * F / L + Ff1 (7)
Wr = Wr0 + h * F / L-Fr1 (8)

Here, Ip is a pitch inertia when the spring of the suspension device is expanded and contracted, and P is a pitch angle. Here, the pitch inertia is a moment of inertia when the pitching fluctuates, and the pitch angle is a rotation angle at the time of pitching about the axis in the left-right direction of the vehicle passing through the center of gravity G1. Further, P ′ (a first differential value of P) is a pitch rate, and P ″ (a second differential value of P, that is, a differential value of the pitch rate) is a pitch rate acceleration. Here, the pitch rate is a change amount of the pitch angle per unit time. Solving the relationship between the driving force Ff of the front wheels and the driving force Fr of the rear wheels under the condition that the differential value of the pitch rate is 0 “zero”, the equations (6) to (8) are solved.
Fr = (h−Lf * tan θf) / (Lr * tan θr−h) * Ff (9)
The relationship holds.

Then, with respect to the total driving force F obtained based on the vehicle speed and the accelerator opening, the front wheel driving force Ff and the rear wheel driving force fr are F = Ff + Fr.
If the distribution ratio between the driving force of the front wheels and the driving force of the rear wheels is controlled so as to satisfy this relationship, the pitching of the vehicle body 2 can be suppressed. In this specific example, either “pitching suppression control” for suppressing pitching or “bouncing suppression control” for suppressing bouncing can be selected and performed. That is, both controls are not performed simultaneously (in parallel). In this specific example, the vehicle 1 is configured such that the height hfs of the swing axis ORf and the height hfr of the swing axis ORr are lower than the height h of the center of gravity G1 of the vehicle 1. It is assumed. Further, it is assumed that the swing axis ORf and the swing axis ORr are disposed between the front axle Zf and the rear axle Zr in the front-rear direction of the vehicle 1.

  By the way, when performing the bouncing suppression control or the pitching suppression control described above, if the driving force applied to the front wheels or the rear wheels is “positive”, the motor is controlled by powering and the driving force is secured by the motor. On the other hand, when the driving force applied to the front wheel or the rear wheel is “negative”, the braking force applied to the wheel can be generated by the braking device. It is also possible to apply a braking force to the wheels by regeneratively controlling the electric motor. When the braking force is applied to the wheels in this way, the efficiency of converting the electric energy of the power source 16 into the driving force decreases. Therefore, in this specific example, “control for suppressing reduction in efficiency of converting electric energy of the power supply 16 into driving force” (hereinafter, abbreviated as “control for suppressing reduction in efficiency”) can be performed. . An example of the “control for suppressing the decrease in efficiency” will be described based on the flowchart of FIG. The control example in FIG. 1 is performed while the accelerator pedal is depressed and the vehicle 1 is traveling. A signal input to the electronic control unit 23 is processed to determine whether to start bouncing suppression control and pitching suppression control (step S1).

  For example, if the pitching amount of the vehicle body 2 is equal to or greater than the threshold value stored in advance in the electronic control unit 23, an affirmative determination is made in step S1, and the pitching amount of the vehicle body 2 is stored in advance in the electronic control unit 23. If it is less than the threshold value, a negative determination is made in step S1. If the bouncing amount of the vehicle body 2 is equal to or greater than the threshold value stored in advance in the electronic control unit 23, an affirmative determination is made in step S1, and the bouncing amount of the vehicle body 2 is stored in advance in the electronic control unit 23. If it is less than the threshold value, a negative determination is made in step S1.

  If a negative determination is made in step S1, the process returns. On the other hand, if the determination in step S1 is affirmative, the front wheel driving force Ff and rear wheel driving force Fr instructed by bouncing suppression control, or the front wheel driving force Ff instructed by pitching suppression control. Then, it is determined whether or not the driving force instructed by any of the suppression control among the driving forces Fr of the rear wheels is a negative driving force (braking force) (step S2). Based on the determination in step S2, if either the driving force instructed in the pitching suppression control or the driving force instructed in the bouncing suppression control has a negative driving force, the negative driving force is instructed. Suppression control is prohibited (step S3), and the process returns to step S1. That is, when the driving force instructed by the pitching suppression control is negative, the pitching suppression control is prohibited. On the other hand, when the driving force instructed by the bouncing suppression control is negative, the bouncing suppression control is prohibited. In step S3, it is permitted to perform the suppression control that is not prohibited.

  On the other hand, if the driving force instructed in any suppression control is not negative at the time of determination in step S2, a negative determination is made in that step S2 to start either bouncing suppression control or pitching suppression control ( Step S4) and return to Step S1. In this step S4, for example, it is possible to select and perform the suppression control with the larger vibration amount. The control example of FIG. 1 will be described using the coordinates of FIG. FIG. 4 is a map for obtaining the driving force of the front wheels and the driving force of the rear wheels when performing the pitching suppression control and the bouncing suppression control. In FIG. 4, the horizontal axis represents the driving force Ff for the front wheels, and the vertical axis represents the driving force Fr for the rear wheels. Both driving forces Ff and Fr are shown as “positive” and “negative” with the origin “zero · kN” as a boundary. In FIG. 4, the driving force corresponding to Equation 9 described in the pitching suppression control is indicated by a straight line A1, the driving force corresponding to Equation 5 described in the bouncing suppression control is indicated by a straight line B1, and the total driving force is shown. F is indicated by a straight line C1.

  The straight lines A1 and B1 are both line segments that pass through the origin, and the front wheel driving force Ff and the rear wheel driving force Fr in the pitching suppression control are obtained from the intersection D1 of the straight line A1 and the straight line C1. Further, from the intersection E1 between the straight line B1 and the straight line C1, the front wheel driving force Ff and the rear wheel driving force Fr in the bouncing suppression control are obtained. In FIG. 4, since the front wheel driving force Ff in the pitching suppression control is positive and the rear wheel driving force Fr is negative, it is prohibited to perform the pitching suppression control. On the other hand, since both the front wheel driving force Ff and the rear wheel driving force Fr in the bouncing suppression control are positive, it is permitted to perform the bouncing control. In addition, although the case where the driving force instruct | indicated by pitching suppression control is negative is shown by the coordinate of FIG. 4, the driving force instruct | indicated by bouncing suppression control may be negative.

  As described above, when the control example of FIG. 1 is executed, it is prohibited to perform the suppression control in which a negative driving force is instructed as the driving force of the front wheels or the rear wheels among the bouncing suppression or the pitching suppression control. Therefore, it can be suppressed that “a positive driving force is applied to one wheel and a negative driving force is applied to the other wheel, which reduces the efficiency of converting electric energy into the driving force”.

  Here, the correspondence between the configuration described in the specific example and the configuration of the present invention will be described. The motors 11, 12, 13, 14 and the braking devices 18, 19, 20, 21 and the hydraulic control device 22 and the electronic control. The device 23 corresponds to the control device in the present invention. The control example of FIG. 1 corresponds to claim 1 of the present invention. The correspondence between the functional means shown in FIG. 1 and the configuration of the present invention will be described. This corresponds to the judging means in the invention, and step S3 corresponds to the prohibiting means in the present invention.

  Next, a second control example that can be performed by the vehicle 1 will be described based on the flowchart of FIG. The control example of FIG. 5 is performed while the accelerator pedal is depressed and the vehicle 1 is traveling. In FIG. 5, first, the determination in step S1 is made. The process of step S1 is the same as the process of step S1 of FIG. If a negative determination is made in step S1, the process returns. On the other hand, if a positive determination is made in step S1, the process proceeds to step S11. In step S11, the first to third determinations are made. In the first determination, it is determined whether or not the bouncing amount is equal to or less than a threshold value stored in advance in the electronic control unit 23. The threshold value α ′ stored in the electronic control unit 23 is a value obtained by a vibration test or simulation of the vehicle body. Then, the acceleration in the vertical direction of the vehicle body 2 is measured in a state where the accelerator pedal is depressed, and it is determined whether or not the measured value is equal to or less than a threshold value. In the second determination, it is determined whether either the front wheel driving force Ff or the rear wheel driving force Fr instructed by the pitching suppression control is negative. In the third determination, it is determined whether or not both the front wheel driving force Ff and the rear wheel driving force Fr instructed by the bouncing suppression control are positive.

  If all of the first to third determinations are positive, the determination is affirmative in step S11 and the process proceeds to step S12. In step S12, control for suppressing pitching is first performed for a predetermined time T, then bouncing suppression control is performed, and the process returns to step S1. Here, the predetermined time T is set according to the size of the bouncing amount. Specifically, the predetermined time T is set to be relatively long as the bouncing amount is relatively small. On the other hand, if any one of the first determination to the third determination is negative in Step S11, the determination is negative in Step S11 and the process proceeds to Step S3. The processing in step S3 is the same as the processing in step S3 in FIG. For example, at the time of determination in step S11, the bouncing amount exceeds the value stored in the electronic control unit 23, and the driving force instructed by the bouncing suppression control or the driving force instructed by the pitching suppression control If either one is negative, a negative determination is made in step S11, and if the process proceeds to step S3, the suppression control in which the instructed driving force is negative is prohibited, and the driving force is The positive restraint control is allowed and returns.

  The coordinates corresponding to the flowchart of FIG. 5 will be described with reference to FIG. The technical meaning of FIG. 6 is the same as the technical meaning of FIG. The items shown in FIG. 6 are basically the same as the items shown in FIG. In FIG. 6, the driving force Fr of the rear wheels obtained from the intersection D1 indicated by the pitching suppression control is negative. Therefore, the front wheel driving force Ff and the rear wheel driving force Fr are obtained from the intersection J1 between the straight line C1 and the axis indicating the front wheel driving force Ff. The front wheel driving force Ff obtained from the intersection J1 is positive, and the rear wheel driving force Fr is “zero · kN”. Further, the front wheel driving force Ff obtained from the intersection point J1 is smaller than the front wheel driving force Ff obtained from the intersection point D1. The process of setting the front wheel driving force Ff to be positive and the rear wheel driving force Fr to “zero · kN” is performed for a predetermined time T, and the bouncing suppression control is performed after the predetermined time T has elapsed. . This is control for obtaining the front wheel driving force Ff and the rear wheel driving force Fr from the intersection E1, as in the first control example.

  Furthermore, FIG. 7 shows an example of a time chart corresponding to the flowchart of FIG. In FIG. 7, the horizontal axis represents time, and the vertical axis represents front wheel driving force Ff and rear wheel driving force Fr. Before time t1 in FIG. 7, neither bouncing suppression control nor pitching suppression control is performed. The time t1 means the time point when the determination is affirmative in step S11. Before the time t1, the front wheel driving force Ff and the rear wheel driving force Fr are both positively controlled. After the time t1, the front wheel driving force Ff is positive and smaller (less) than the front wheel driving force Ff before the time t1. On the other hand, the driving force Fr of the rear wheels is controlled to “zero · kN”. Further, when the predetermined time T elapses from time t1 and becomes time t2, the driving force Ff of the front wheels is positive and is smaller than the driving force Ff between time t1 and time t2. On the other hand, after time t2, the driving force Fr of the rear wheels is positively controlled.

  As described above, in the second control example, when an affirmative determination is made in step S11, processing for suppressing pitching is performed for a predetermined time T, and then bouncing suppression control is performed. For this reason, when the bouncing amount is relatively small, pitching can be suppressed first, and then bouncing can be suppressed. Therefore, bouncing can be suppressed while suppressing the driver's uncomfortable feeling by suppressing pitching, and drivability is improved.

  Next, a modified example of the flowchart of FIG. 5 will be described. In this modified example, in step S11, it is determined whether or not the pitching amount is equal to or less than a threshold value stored in advance in the electronic control unit 23 in the first determination, and the driving force of the front wheels instructed by the bouncing suppression control or It is determined whether any of the driving forces of the rear wheels is negative, and it is determined whether both the driving force of the front wheels and the driving force of the rear wheels that are instructed by the pitching suppression control are positive. If all of the first to third determinations are positive, the determination is positive in step S11. Further, in step S12, in order to suppress bouncing, a process of outputting the driving force of the front wheels and the rear wheels for a predetermined time T is performed, and then the driving force of the front wheels and the rear wheels is set to be positive for pitching suppression control. Will be processed.

  The flow chart of FIG. 5 corresponds to claims 1 to 3, and the correspondence between the functional means shown in FIG. 5 and the configuration of the present invention will be explained. Step S1 is a decision in the present invention. Steps S3, S11, and S12 correspond to the prohibiting means in the present invention.

  In place of the vehicle of the power train shown in FIG. 2, an engine is mounted as a driving force source, and a power train having a configuration in which the power of the engine is distributed to the front wheels and the rear wheels by transfer. It is also possible to carry out the present invention in a wheel drive vehicle. In this four-wheel drive vehicle, the positive driving force distributed to the front wheels and the rear wheels is controlled by transfer, and the negative driving force (braking force) applied to the front wheels and rear wheels is controlled by the braking device. That's fine. According to this configuration, when fuel is burned by the engine, heat energy is converted into kinetic energy and transmitted to the wheels, negative driving force is applied to the front wheels or rear wheels, and the fuel consumption of the engine Can be suppressed. The present invention can also be implemented in a four-wheel drive vehicle configured to generate a driving force transmitted to wheels by a hydraulic motor. The present invention can also be used in a vehicle in which a plurality of front wheels are arranged in the front-rear direction of the vehicle or a vehicle in which a plurality of rear wheels are arranged in the front-rear direction.

It is a flowchart which shows the 1st control example performed with the vehicle made into the object of this invention. It is a top view which shows the structural example of the vehicle made into the object of this invention. 1 is a schematic side view of a vehicle that is an object of the present invention. In the first control example shown in FIG. 1, the coordinates are used for obtaining the driving force of the wheels when suppressing the vibration of the vehicle body. It is a flowchart which shows the 2nd example of control performed with the vehicle made into the object of this invention. In the second control example shown in FIG. 5, the coordinates are used for obtaining the driving force of the wheel when suppressing the vibration of the vehicle body. It is an example of the time chart corresponding to the 2nd example of control of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Car body, 3, 5, 7, 9 ... Suspension device, 4 ... Right front wheel, 6 ... Left front wheel, 8 ... Right rear wheel, 10 ... Left rear wheel, 11, 12, 13, 14 ... Electric motor 18, 19, 20, 21 ... braking device, 22 ... hydraulic control device, 23 ... electronic control device.

Claims (5)

A front wheel and a rear wheel arranged at different positions in the longitudinal direction of the vehicle body, the front wheel and the rear wheel are attached to the vehicle body, and the front wheel and the rear wheel can be relatively moved in the vertical direction independently of the vehicle body. And a control device that independently controls the driving force and braking force of the front wheel and the braking force and driving force of the rear wheel, and the front and rear of the vehicle body are vertically moved in the same phase. Control for detecting the presence or absence of bouncing that vibrates in the direction, control for detecting the presence or absence of pitching in which the front and rear of the vehicle body vibrate up and down in opposite phases, and when the bouncing or the pitching occurs, Pitching suppression control or bouncing for suppressing the pitching by applying a driving force or a braking force to the front wheels and applying a driving force or a braking force to the rear wheels. EITHER a bouncing suppressing control win, in the vibration suppression apparatus for a vehicle,
Determination means for determining whether to apply braking force to the front wheel or the rear wheel in at least one of the bouncing suppression control and the pitching suppression control;
Prohibiting means for prohibiting the suppression control determined to give a braking force to the front wheel or the rear wheel and permitting the suppression control determined to give a driving force to the front wheel or the rear wheel; A vehicle vibration suppressing device comprising:   The prohibiting means determines a vibration amount in the vertical direction of the vehicle body in the permitted control when prohibiting any one suppression control and permitting the other suppression control, and the vibration amount is a predetermined value. It is determined whether or not the vibration amount is equal to or less than the predetermined value, and if the vibration amount is equal to or less than a predetermined value, the prohibited suppression control is performed for a predetermined time, and then the permitted suppression control is performed. The vehicle vibration suppression device according to claim 1, further comprising means.   The vehicle according to claim 2, wherein the prohibiting unit includes a unit that sets the predetermined time relatively longer as the amount of vibration in the vertical direction of the vehicle body in the permitted suppression control is relatively small. Vibration suppression device.   The vehicle vibration suppression device according to any one of claims 1 to 3, further comprising an electric motor that applies a driving force and a braking force to at least one of the front wheel and the rear wheel.   5. The vehicle vibration suppression device according to claim 4, wherein the electric motor is supported by the vehicle body via the suspension device together with the front wheel or the rear wheel.

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