JP2009273275A - Controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a vehicle, capable of properly suppressing bouncing and pitching without deteriorating drivability of the vehicle. <P>SOLUTION: The controller for a vehicle generates a driving force or a braking force on front and rear wheels by a driving force generating mechanism based on a driving force distribution ratio calculated to control the pitching or bouncing of a vehicle body in response to the state of the pitching or bouncing. The controller is provided with a driving force changing means for controlling a braking mechanism different from a driving force generating mechanism when the driving force or braking force generated in either front or rear wheels based on the driving force distribution ratio becomes almost zero in order to generate a predetermined braking force on either the front or rear wheels, and adding a driving force canceling the predetermined braking force to the initial driving force or braking force which is almost zero, thereby controlling the driving force generating mechanism to generate a driving force on either the front or rear wheels (steps S5-S7). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention controls the behavior of a vehicle by controlling the distribution ratio between the driving force or braking force generated at the front wheels and the driving force or braking force generated at the rear wheels with respect to the total driving force required for the vehicle. The present invention relates to a vehicle control device.

  2. Description of the Related Art In recent years, a so-called in-wheel motor type vehicle in which a motor is arranged in or near a wheel of a wheel and the wheel is directly driven by the motor has been developed as one form of an electric vehicle. As an advantage of this in-wheel motor system vehicle, the motor provided for each wheel (drive wheel) is individually controlled for rotation, that is, each motor is individually controlled for power running or regenerative control to be applied to each drive wheel. The driving torque or braking torque to be controlled can be individually controlled so that the driving force and braking force of the vehicle can be appropriately controlled according to the running state, and the conventional drive train such as engine and transmission is eliminated. As a result, it is possible to widen the space such as the interior of the vehicle or the trunk room.

  Among these, Patent Document 1 discloses an invention relating to a traveling device that suppresses changes in vehicle behavior such as bouncing and pitching by utilizing the fact that driving torque or braking torque applied to each wheel can be individually controlled. Yes. The traveling device described in Patent Document 1 is a condition that suppresses a load change on the spring of the suspension device and a load on the spring of the front wheel suspension device and a driving reaction of the front wheel acting on the spring of the front wheel suspension device. The relationship between the force and the total driving force of the vehicle, and the relationship between the load on the spring of the rear wheel suspension and the driving reaction force of the rear wheel acting on the spring of the rear wheel suspension and the total driving force of the vehicle Thus, the distribution ratio of the driving force between the front wheels and the rear wheels is obtained, and the front wheels and the rear wheels are driven based on the distribution ratio.

  Further, the traveling device described in Patent Document 1 switches between a driving force distribution ratio that suppresses bouncing of a vehicle and a driving force distribution ratio that suppresses pitching according to a load change on a spring of the suspension device. The distribution ratio is corrected in consideration of the change in the instantaneous rotation center position of the suspension device.

JP 2007-161032 A

  As described above, according to the traveling device described in Patent Document 1, the distribution ratio of the driving force to the front wheels and the rear wheels when controlling the behavior of the vehicle suppresses bouncing and pitching. It is changed depending on the case and set selectively. The distribution ratio of the driving force is corrected and changed in consideration of a change in the instantaneous rotation center position of the suspension device, that is, a change in the instantaneous rotation center angle of the suspension device.

  Therefore, in the traveling device described in Patent Document 1, the distribution ratio of the driving force for suppressing bouncing or pitching changes as the traveling state of the vehicle and the behavior of the vehicle fluctuate during traveling. In some cases, the distribution ratio of the driving force to one of the wheels is a value near 0 (zero), in other words, the driving force generated by either one of the front and rear wheels is a value near 0. In that case, there is a possibility that the driving force generated by one of the driving wheels repeatedly changes positively and negatively from 0 as a boundary. That is, there is a possibility that the driving force and the braking force are alternately and repeatedly generated on one drive wheel. For example, in the case where the drive wheels are driven by an electric motor such as an in-wheel motor, the electric motor repeatedly executes rotation control in the power running state and rotation control in the regenerative state, and the control hunting May occur.

  In this way, when the distribution ratio of the driving force to the front and rear wheels is controlled to suppress fluctuations in vehicle behavior such as bouncing and pitching, the control is performed when the distribution ratio of the driving force to one of the driving wheels becomes a value close to zero. When hunting occurs and driving and braking are repeated on the drive wheels, the passenger is shocked and discomforted, or a rattling noise is generated on the transmission gear between the power source and the drive wheels. As a result, the drivability of the vehicle decreases. For this reason, there is still room for improvement in order to appropriately control fluctuations in vehicle behavior such as bouncing and pitching by controlling the distribution ratio of the driving force to the front and rear wheels without reducing drivability.

  The present invention has been made paying attention to the technical problem described above, and provides a vehicle control device capable of appropriately suppressing fluctuations in vehicle behavior such as bouncing and pitching without deteriorating vehicle drivability. It is intended to provide.

  In order to achieve the above object, the invention of claim 1 is directed to a suspension mechanism that supports at least a front wheel and a rear wheel independently on a vehicle body, and a driving force that is independent of at least the front wheel and the rear wheel. Alternatively, a driving force generation mechanism that generates a braking force and a front wheel that generates a total driving force required for the vehicle to suppress the pitching or bouncing according to the pitching or bouncing state of the vehicle body. Driving force distribution ratio calculating means for calculating a driving force distribution ratio that is a ratio of the driving force or braking force and the driving force or braking force generated on the rear wheel, and the driving force based on the driving force distribution ratio In a vehicle control device that controls a generating mechanism to generate driving force or braking force on the front and rear wheels, the driving force generating mechanism generates the front and rear wheels. In addition to the braking force to be applied, a braking mechanism that generates braking force independently for at least the front wheel and the rear wheel, and a driving force that is generated on one of the front and rear wheels based on the driving force distribution ratio, or A driving force detecting means for detecting that the braking force is a value close to 0, and a case where the driving force detecting means detects that the driving force or the braking force generated on the one wheel is a value near 0 In addition, the brake mechanism is controlled to generate a predetermined braking force on the one wheel, and a driving force that is equal to or substantially equal to the predetermined braking force is used as a driving force or a braking force in the vicinity of 0. In addition, the control apparatus includes a driving force changing unit that controls the driving force generation mechanism to generate the one wheel.

  According to a second aspect of the present invention, in the first aspect of the present invention, the driving force generating mechanism controls at least rotation of an electric motor connected to at least the front wheel and the rear wheel so that power can be transmitted. The control device includes a mechanism that applies driving torque or braking torque to the front wheel and the rear wheel independently.

  The invention according to claim 3 is the in-wheel motor according to claim 2, wherein the electric motor is supported by the vehicle body through the suspension mechanism together with the front and rear wheels, and is incorporated in the wheels of the front and rear wheels, respectively. It is a control device characterized by including.

  According to the first aspect of the present invention, in order to suppress fluctuations in vehicle behavior such as pitching and bouncing, the driving force distribution ratio before and after the driving force or braking force generated independently at the front and rear wheels, in other words, traveling Therefore, the driving force distribution ratio is obtained as the total driving force required for the vehicle to be generated by sharing the front wheel and the rear wheel (or the sharing rate, the distribution rate). Then, based on the front / rear driving force distribution ratio, the driving force or the braking force is generated by the front and rear wheels, thereby suppressing the pitching or bouncing of the vehicle.

  The above driving force distribution ratio varies from time to time depending on the running state of the vehicle and the state of pitching or bouncing. Therefore, when the driving force distribution ratio of either one of the front and rear wheels becomes a value near 0 (zero), The driving force distribution ratio varies from time to time to positive and negative values across zero. That is, when the driving force distribution ratio of either one of the front and rear wheels becomes a value close to 0, the driving force or braking force generated by that one wheel also becomes a value close to 0, and the driving force with 0 being sandwiched between the one wheel. And braking force are repeatedly generated alternately. Therefore, in the invention of claim 1, when the driving force distribution ratio of either one of the front and rear wheels becomes a value near 0, and the driving force or braking force generated on one wheel becomes a value near 0, one of the front and rear wheels A braking torque for generating a predetermined braking force on the wheel is applied by a brake mechanism which is a braking device different from the driving force generation mechanism. In addition, a driving torque for generating a driving force substantially the same as the predetermined braking force on one of the wheels is applied by the driving force generating mechanism.

  Therefore, in one wheel where the driving force distribution ratio becomes a value near 0, the predetermined braking force and magnitude by the brake mechanism are added to the initial driving force or braking force near 0 calculated based on the driving force distribution ratio. Is equivalent to the driving force, in other words, the driving force to which the driving force for canceling the predetermined braking force by the brake mechanism is added. As a result, one wheel with a driving force distribution ratio near zero generates a driving force of a predetermined magnitude that is not near zero, and the driving force and the braking force alternate between zero and zero. The situation that is repeatedly generated, that is, the control hunting when controlling the driving force is avoided. Therefore, it is possible to avoid or suppress the occurrence of shock, uncomfortable feeling or rattling sound due to control hunting, and it is possible to appropriately suppress pitching and bouncing without reducing the drivability of the vehicle.

  According to the invention of claim 2, the electric motor capable of transmitting power independently to the front and rear wheels is provided. Therefore, by controlling the rotation of the electric motor, that is, by controlling the electric motor for power running or regenerative control, a driving torque or a braking torque is applied to the front and rear wheels, respectively. A braking force can be generated on each of the front and rear wheels. As a result, the driving force or braking force of the vehicle can be easily generated independently on the front and rear wheels.

  And according to invention of Claim 3, an in-wheel motor is mounted as an electric motor which gives a driving torque or a braking torque to front-and-rear wheels independently, respectively. Therefore, the driving force or braking force of the vehicle can be generated more easily on the front and rear wheels independently.

  Next, an embodiment of the present invention will be described with reference to the drawings. First, FIG. 1 shows the configuration and control system of a vehicle that is a subject of the present invention. The vehicle Ve shown in FIG. 1 has left and right front wheels 1 and 2 and left and right rear wheels 3 and 4. The front wheels 1 and 2 are supported by the vehicle body Bo of the vehicle Ve via suspension mechanisms 5 and 6 independently of each other, and the rear wheels 3 and 4 are respectively or independently of each other of the suspension mechanisms 7 and 7. 8 is supported by the vehicle body Bo of the vehicle Ve.

  Each of the suspension mechanisms 5 to 8 includes, for example, a strut suspension including a shock absorber with a built-in shock absorber, a coil spring, and a suspension arm, and a wishbone including a coil spring, a shock absorber, and upper and lower suspension arms. Known suspensions such as a type suspension, and these various suspensions are appropriately selected and installed.

  The electric motors 9 and 10 are incorporated in the front wheels 1 and 2 and the electric motors 11 and 12 are incorporated in the rear wheels 3 and 4, respectively. The front wheels 1 and 2 and the rear wheels 3 and 4, respectively. It is connected so that power can be transmitted. That is, the electric motors 9 and 10 of the front wheels 1 and 2 and the electric motors 11 and 12 of the rear wheels 3 and 4 are so-called in-wheel motors 9 to 12, and together with the front wheels 1 and 2 and the rear wheels 3 and 4, the vehicle Ve. It is placed under the spring. Then, by independently controlling the rotation of the in-wheel motors 9 to 12, the driving force and braking force generated on the front wheels 1 and 2 and the rear wheels 3 and 4 can be independently controlled. It is like that.

  Each of these in-wheel motors 9 to 12 is composed of, for example, an AC synchronous motor, and is connected to a power storage device 14 such as a battery or a capacitor via an inverter 13. Therefore, when the in-wheel motors 9 to 12 are driven, the DC power of the power storage device 14 is converted into AC power by the inverter 13, and the AC power is supplied to the in-wheel motors 9 to 12. The wheel motors 9 to 12 are powered to apply driving torque to the front wheels 1 and 2 and the rear wheels 3 and 4. Each of the in-wheel motors 9 to 12 can be regeneratively controlled using the rotational energy of the front wheels 1 and 2 and the rear wheels 3 and 4. That is, at the time of regeneration and power generation of each in-wheel motor 9 to 12, the rotational (kinetic) energy of the front wheels 1 and 2 and the rear wheels 3 and 4 is converted into electric energy by the in-wheel motors 9 to 12, Is stored in the power storage device 14 via the inverter 13. At this time, braking torque based on regenerative / generated power is applied to the front wheels 1 and 2 and the rear wheels 3 and 4.

  Brake mechanisms 15, 16, 17, and 18 are provided between the wheels 1 to 4 and the corresponding in-wheel motors 9 to 12, respectively. Each of the brake mechanisms 15 to 18 is a known braking device such as a disc brake or a drum brake, and these various braking devices are appropriately selected and installed. The brake mechanisms 15 to 18 are, for example, brake caliper pistons (not shown) that generate braking force on the wheels 1 to 4 by hydraulic pressure fed from a master cylinder (not shown) or the like. It is connected to a brake actuator 19 that operates a brake shoe (not shown).

  The inverter 13 and the brake actuator 19 are connected to an electronic control unit (ECU) 20 that controls the rotation state of the in-wheel motors 9 to 12 or the operation state of the brake actuator 19.

  The electronic control device 20 includes, for example, an accelerator sensor 21 that detects a driver's accelerator operation amount from an accelerator pedal depression amount (or angle, pressure), etc., and a brake pedal depression amount (or angle, pressure). A brake sensor 22 for detecting a brake operation amount of the person, a vertical acceleration sensor 23 for detecting a sprung displacement acceleration in the vertical direction of the vehicle body Bo, a stroke sensor 24 for detecting a stroke amount of each suspension mechanism 5 to 8, or a vehicle speed. A signal from various sensors such as a sensor, a rotation speed sensor of each driving wheel 1, 2, 3, 4 and a sensor (none of which is shown) for detecting a charge amount of the power storage device 14 and a signal from the inverter 13 It is configured to be entered.

  Among these, based on signals input from the accelerator sensor 21 and the brake sensor 22, a required driving force or a required braking force corresponding to the driver's accelerator operation amount and brake operation amount, that is, for driving or braking the vehicle Ve. The total driving force is calculated and obtained. Further, the output torque (motor torque) of each of the in-wheel motors 9 to 12 is calculated and obtained based on the signal input from the inverter 13. For example, when it is detected from the input signal from the inverter 13 that the in-wheel motors 9 to 12 are controlled to be powered, the power amount or current supplied to the in-wheel motors 9 to 12 at that time A value is detected, and the motor torque of each in-wheel motor 9, 12 can be calculated based on the detected value. Further, bouncing and pitching occurring in the vehicle body Bo can be detected based on signals input from the vertical acceleration sensor 23 and the stroke sensor 24.

  On the other hand, from the electronic control unit 20, a signal for controlling the rotation of each in-wheel motor 9, 12 through the inverter 13 and the operation of each brake mechanism 15, 18 through the brake actuator 19, respectively. A control signal is output.

  Therefore, the total driving force required for the vehicle Ve is determined based on the signals from the accelerator sensor 21 and the brake sensor 22 described above, and the power running of each of the in-wheel motors 9 to 12 is generated so as to generate the total driving force. The regeneration state and the operation state of the brake actuator 19, that is, the brake mechanisms 15 to 18 are controlled.

  Further, bouncing and pitching of the vehicle Ve are detected based on the signal from the vertical acceleration sensor 23 or the stroke sensor 24, and, specifically, depending on the bouncing or pitching state, the bouncing generated in the vehicle Ve or The driving force (or braking force) generated by the front wheels 1 and 2 and the driving force (or braking force) generated by the rear wheels 3 and 4 with respect to the total driving force required for the vehicle Ve so as to suppress pitching. The driving force distribution ratio that is a ratio of Based on the driving force distribution ratio, the power running / regenerative state of each in-wheel motor 9, 12 and the operation state of each brake mechanism 15, 18 are controlled.

  As described above, the driving force distribution ratio set when controlling the power running / regenerative state of each in-wheel motor 9, 12 and the operating state of each brake mechanism 15, 18 depends on the traveling state and bouncing of the vehicle Ve. Or it fluctuates at any time according to the state of pitching. Specifically, for example, as shown in FIG. 2, the value of the driving force distribution ratio changes as the positions of the instantaneous rotation centers Cf and Cr in the side view of the vehicle Ve of the suspension mechanisms 5 to 8 change. . Therefore, the driving force distribution ratio is constantly changing while the vehicle Ve is traveling, and the driving force distribution ratio for one of the front wheels 1 and 2 and the rear wheels 3 and 4 is 0 (zero) or near 0 (zero). May be the value of. When the driving force distribution ratio becomes 0 or a value close to 0, the driving force and the braking force are alternately and repeatedly generated on one of the wheels 1 and 2 (or 3 and 4). As a result, the passenger may be shocked or discomforted, and the drivability of the vehicle Ve may be reduced. Therefore, the control device for the vehicle Ve according to the present invention is configured to execute the following control so that bouncing and pitching can be appropriately suppressed without reducing drivability.

  FIG. 3 is a flowchart for explaining the control example, and the routine shown in this flowchart is repeatedly executed every predetermined short time. Further, this control example is directed to control for suppressing pitching or bouncing when the vehicle Ve is pitched or bouncing. That is, the pitching or bouncing of the vehicle Ve is detected by the vertical acceleration sensor 23 or the stroke sensor 24 described above, and the detected pitching or bouncing may affect the drivability of the vehicle Ve and needs to be suppressed. This control is executed when it is determined.

  In FIG. 3, first, the driving force generated on the front wheels 1 and 2 and the driving force generated on the rear wheels 3 and 4 are calculated by the conventional pitching suppression control or bouncing suppression control (step S1). As described above, first, based on the driver's accelerator operation and brake operation, the total driving force for running or braking the vehicle Ve is obtained, and the total driving force is calculated from the front wheels 1, 2 and the rear wheels. The ratio of sharing the driving force between the front wheels 1, 2 and the rear wheels 3, 4 so as to suppress the pitching or bouncing generated in the vehicle Ve when being divided and generated by the vehicles 3, 4, that is, the front wheels 1, 2 And the driving force distribution ratio between the rear wheels 3 and 4. Based on the driving force distribution ratio, the driving force generated on the front wheels 1 and 2 and the driving force generated on the rear wheels 3 and 4 are obtained.

Among these, the calculation method of the driving force generated by each of the wheels 1 to 4 during the pitching suppression control will be described. For example, as shown in FIG. 2 described above, the vehicle Ve is compared with the wheel base L of the vehicle Ve. The distance between the center of gravity Cg of the vehicle Ve and the axles of the front wheels 1 and 2 in the front-rear direction (left-right direction in FIG. 2) is Lf, and the center of gravity Cg of the vehicle Ve with respect to the wheel base L and the axles of the rear wheels 3 and 4 The total driving force of the vehicle Ve (Lr) is Lr, the instantaneous rotation angle of the suspension mechanisms 5 and 6 of the front wheels 1 and 2 is θf, and the instantaneous rotation angle of the suspension mechanisms 7 and 8 of the rear wheels 3 and 4 is θr. That is, the driving force generated at the front wheels 1 and 2 with respect to the required driving force F is Ff, the driving force generated at the rear wheels 3 and 4 with respect to the total driving force F is Fr, and the driving force generated at the front wheels 1 and 2. Ff is the component force in the height direction (vertical direction in FIG. 2) of the vehicle Ve, Ff1, rear wheel , 4 is a component force in the height direction of the vehicle Ve Fr1, a sprung front load acting on the axles of the front wheels 1 and 2 is Wf, and a sprung rear acting on the axles of the rear wheels 3 and 4 The load is Wr, the sprung front side static load acting on the axles of the front wheels 1 and 2 is Wf0, the sprung rear side static load acting on the axles of the rear wheels 3 and 4 is Wr0, and the height of the center of gravity Cg of the vehicle Ve ( That is, if h is the position of the center of gravity Cg in the height direction of the vehicle Ve, P is the angular acceleration in the pitching direction of the vehicle body Bo, and Ip is the moment of inertia in the pitching direction of the vehicle body Bo, the following (1) to (3 ) Is established.
Ip * P "= Wr * Lr-Wf * Lf (1)
Wf = Wf0−h × F / L + Ff1 (2)
Wr = Wr0 + h × F / L-Fr1 (3)
Here, the relationship between the driving force Ff and the driving force Fr is solved so that the angular acceleration P "of the vehicle body Bo in the pitching direction becomes 0, that is," Wr × Lr−Wf × Lf = 0 ”.
Fr = {(h−Lf × tan θf) / (Lr × tan θr−h)} × Ff (4)
The relationship expressed by

  The relationship of the equation (4) obtained as described above is an orthogonal coordinate in which the driving force Ff generated at the front wheels 1 and 2 is plotted on the horizontal axis and the driving force Fr generated at the rear wheels 3 and 4 is plotted on the vertical axis. As shown above, it can be represented by the straight line l1 in FIG. Then, the driving force distribution for suppressing the pitching generated in the vehicle Ve from the intersection A between the straight line l1 and the straight line l0 representing the total driving force F (= Ff + Fr) of the vehicle Ve on the orthogonal coordinates of FIG. A ratio is determined, and a driving force Ff generated at the front wheels 1 and 2 and a driving force Fr generated at the rear wheels 3 and 4 to suppress pitching are determined based on the driving force distribution ratio. That is, the horizontal axis component of the intersection A in the orthogonal coordinates in FIG. 4 is obtained as the driving force Ff, and the vertical axis component is obtained as the driving force Fr.

On the other hand, the calculation method of the driving force generated by each of the wheels 1 to 4 at the time of the bouncing suppression control will be described. As described above, the wheel base of the vehicle Ve is set to L, and the suspension mechanisms 5 and 6 of the front wheels 1 and 2 are set. The instantaneous rotation angle is θf, the instantaneous rotation angle of the suspension mechanisms 7 and 8 of the rear wheels 3 and 4 is θr, and the driving force generated by the front wheels 1 and 2 with respect to the total driving force (required driving force) F of the vehicle Ve Ff, the driving force generated by the rear wheels 3 and 4 with respect to the total driving force F, Fr, the driving force Ff generated by the front wheels 1 and 2 in the height direction of the vehicle Ve is Ff1, and the rear wheels 3 and 4 Fr1 is the component force in the height direction of the vehicle Ve of the driving force Fr generated by the vehicle, Wf is the sprung front load acting on the axles of the front wheels 1 and 2, and the sprung rear load acting on the axles of the rear wheels 3 and 4. Wr, the sprung front side static load acting on the axles of the front wheels 1, 2 is Wf0, the rear wheels 3, 4 Sprung rear static load acting on the shaft Wr0, and the height of the center of gravity Cg of the vehicle Ve is is h, the following (5) to (8) of the relationship is established.
Wf = Wf0−h × F / L + Ff1 (5)
Wr = Wr0 + h × F / L-Fr1 (6)
Ff1 = Ff × tanθf (7)
Fr1 = Fr x tanθr (8)
Here, when the relationship between the driving force Ff and the driving force Fr is solved so that the load fluctuation in the bouncing direction of the vehicle body Bo becomes zero, that is, as “Wf + Wr = Wf0 + Wr0”,
Fr = (tan θf / tan θr) × Ff (9)
The relationship expressed by

  When the relationship of the equation (9) obtained as described above is shown on the orthogonal coordinates in FIG. 4 described above, it can be represented by a straight line l2 in FIG. Then, the driving force distribution for suppressing the bouncing generated in the vehicle Ve from the intersection B between the straight line l2 and the straight line l0 representing the total driving force F (= Ff + Fr) of the vehicle Ve on the orthogonal coordinates of FIG. A ratio is obtained, and a driving force Ff generated at the front wheels 1 and 2 and a driving force Fr generated at the rear wheels 3 and 4 to suppress bouncing are obtained based on the driving force distribution ratio. That is, the horizontal axis component of the intersection B in the orthogonal coordinates of FIG. 4 is obtained as the driving force Ff, and the vertical axis component is obtained as the driving force Fr.

  Returning to the flowchart of FIG. 3, in step S1, the driving force Ff generated on the front wheels 1 and 2 and the driving force Fr generated on the rear wheels 3 and 4 in the conventional pitching suppression control or bouncing suppression control as described above. Is calculated, the motor torque Tm0 output from each of the in-wheel motors 9 and 12 to generate the driving forces Ff and Fr by the wheels 1 to 4 is calculated (step S2). Specifically, the motor torque Tm0f of the in-wheel motors 9 and 10 for generating the driving force Ff at the front wheels 1 and 2 and the in-wheel motors 11 and 12 for generating the driving force Fr at the rear wheels 3 and 4. The motor torque Tm0r is calculated and obtained.

  Subsequently, it is determined whether one of the driving forces Ff and Fr obtained in step S1 is a value in the vicinity of 0 (zero) (step S3). That is, it is determined whether one of the driving forces Ff and Fr is a value in the region near 0 where control hunting may occur. Specifically, the range from “threshold“ −α ”to“ threshold “α” ”in which one of the driving forces Ff and Fr is set in advance as an area near 0 in which control hunting may occur. Is determined, that is, whether “−α <driving force Ff (or Fr) <α” is satisfied. In other words, is either the absolute value of the driving force Ff or the absolute value of the driving force Fr less than a predetermined value α set in advance as a threshold for determining that control hunting may occur? It is determined whether or not.

  Since none of the values of the driving forces Ff and Fr is within the range of “threshold“ −α ”to threshold“ α ””, in other words, both the absolute value of the driving force Ff and the absolute value of the driving force Fr are both. If it is determined negative in this step S3 because it is less than the predetermined value α, it can be determined that there is no possibility that control hunting will occur. Therefore, the process proceeds to step S4, where conventional pitching suppression control or bouncing suppression control is performed. Similarly, the rotations of the in-wheel motors 9 to 12 are controlled so as to output the motor torque Tm0 (that is, Tm0f, Tm0r) calculated in step S1. Thereafter, this routine is once terminated.

  On the other hand, since the value of either one of the driving forces Ff and Fr is within the range of “threshold“ −α ”to threshold“ α ””, in other words, the absolute value of the driving force Ff and the driving force. If at least one of the absolute value of Fr is greater than or equal to the predetermined value α and the determination is affirmative in step S3, the process proceeds to step S5, and a predetermined braking force is applied to each of the wheels 1 to 4. In order to generate the brake torque, a brake torque Tb, which is a brake torque that is applied to the wheels 1 to 4 by operating the brake mechanisms 15 to 18 in a braking state, is calculated.

  Specifically, the brake torque Tbf by the brake mechanisms 15 and 16 for generating a predetermined braking force on the front wheels 1 and 2 or the brake mechanism 17 and the brake mechanism 17 for generating a predetermined braking force on the rear wheels 3 and 4 18 is calculated and obtained. For example, when the value of the driving force Ff generated at the front wheels 1 and 2 is a value close to 0 (within the range of “threshold“ −α ”to threshold“ α ””), the brake torque Tbf is obtained and the rear wheel When the value of the driving force Fr generated at 3 and 4 is a value close to 0, the brake torque Tbr is obtained. The predetermined braking force is set so that, for example, when any one of the driving forces Ff (or Fr) becomes a value close to 0, the value becomes about twice as large as the threshold value α. .

  When the brake torque Tb (Tbf or Tbr) is calculated in step S5, a motor torque Tm1 obtained by adding a torque corresponding to the brake torque Tb to the motor torque Tm0 calculated in step S2 is calculated ( Step S6). That is, the motor torque Tm1 is obtained by adding to the motor torque Tm0 a torque that is equal in magnitude to the brake torque Tb and in the opposite direction (that is, a torque that cancels out the brake torque Tb). Specifically, when the value of the driving force Ff generated on the front wheels 1 and 2 is a value close to 0, the motor torque of the in-wheel motors 9 and 10 for generating the driving force Ff on the front wheels 1 and 2. When the motor torque Tm1f is obtained by adding a torque that is equal in magnitude and reverse to the brake torque Tbf to Tm0f, and the value of the driving force Fr generated in the rear wheels 3 and 4 is a value near zero Motor torque Tm0r of the in-wheel motors 11 and 12 for generating the driving force Fr on the rear wheels 3 and 4 is added with torque equal in magnitude to the brake torque Tbr and in the opposite direction. Tm1r is obtained.

  As described above, when one of the driving force distribution ratios for suppressing pitching or bouncing becomes a value near 0, that is, when one of the driving forces Ff and Fr becomes a value near 0, the driving force Ff or In some cases, the value of Fr changes between 0 and 0. For example, when the driving force Fr generated by the rear wheels 3 and 4 becomes a value close to 0, the value of the driving force Fr is slightly larger in the positive direction than 0 (state shown in FIG. 4A). And the state where the value of the driving force Fr is slightly smaller in the negative direction than 0 (zero) (the state shown in FIG. 4B) may be repeated. As a result, hunting may occur in the rotation control of the in-wheel motors 11 and 12 (or 9, 10).

  Therefore, as described above, the brake mechanisms 17 and 18 (or the brake mechanism 15) are applied to the rear wheels 3 and 4 (or the front wheels 1 and 2) on the side where the driving force Fr (or the driving force Ff) has a value close to zero. 16), the braking torque (that is, the braking torque Tm) is applied, and the driving torque (that is, the motor torque Tm1) that cancels the braking torque Tm is also applied, whereby the rear wheels 3, 4 (or the front wheels 1, 2) are applied. The driving force Fr (or driving force Ff) generated in step) is set to a positive value (that is, driving force) that is not near 0 (the state shown in FIG. 5).

  Therefore, while the vehicle Ve is traveling, the positions of the instantaneous rotation centers Cf and Cr of the suspension mechanisms 5 to 8 fluctuate, and the rear wheels 3 and 4 of the driving force distribution ratio for suppressing pitching (or bouncing). The side (or front wheel 1, 2 side) becomes a value near 0 (zero), that is, the driving force Fr (or driving force Ff) becomes a value near 0, and the rear wheels 3, 4 side (or front wheels 1, 2) 5) When the value of the driving force distribution ratio changes between 0 and positive and negative, for example, the state where the value of the driving force distribution ratio on the rear wheels 3 and 4 side is slightly larger than 0 in the positive direction (see FIG. 5). (The state shown in FIG. 5A) and the state where the value of the driving force distribution ratio on the rear wheels 3 and 4 side is slightly smaller in the negative direction than 0 (the state shown in FIG. 5B). Motor torque Tm1 actually output by the in-wheel motors 11 and 12 even if , 0 for a positive value not in the vicinity, a situation which occurs hunting in the rotation control of the in-wheel motors 11 and 12 is avoided.

  When the brake torque Tb and the motor torque Tm1 are calculated as described above, the brake mechanisms 15, 16 (or so that the brake torque Tb (Tbf or Tbr) and the motor torque Tm1 (Tm1f or Tm1r) are output. 17, 18) and the rotation of the in-wheel motors 9, 10 (or 11, 12) are controlled. Thereafter, this routine is once terminated.

  As described above, according to the control for suppressing the pitching or bouncing of the vehicle Ve according to the present invention, any of the driving force distribution ratios for the front wheels 1 and 2 and the rear wheels 3 and 4 calculated for suppressing the pitching or bouncing. When one of them becomes a value near 0, the braking torque for generating a predetermined braking force on one of the wheels 1, 2 (or 3, 4) is in-wheel motor 9, 10 (or 11, 12). Is applied by a brake mechanism 15, 16 (or 17, 18) which is a braking device different from the above. In addition, a driving torque for generating a driving force substantially equal to the predetermined braking force on one of the wheels 1, 2 (or 3, 4) is generated by the in-wheel motor 9, 10 (or 11). , 12).

  Therefore, in the one wheel 1, 2 (or 3, 4) whose driving force distribution ratio becomes a value near 0, the initial driving force or braking force near 0 calculated based on the driving force distribution ratio is used. The driving mechanism cancels out the predetermined braking force by the brake mechanism 15, 16 (or 17, 18), in other words, the driving force substantially equal to the predetermined braking force by the brake mechanism 15, 16 (or 17, 18). A driving force to which a force component is added is generated. As a result, one of the wheels 1, 2 (or 3, 4) having a driving force distribution ratio close to 0 generates a driving force of a predetermined magnitude that is not close to 0. Control hunting in which the braking force is repeatedly generated alternately at zero is avoided. Therefore, it is possible to avoid or suppress the occurrence of shock, uncomfortable feeling or rattling sound due to control hunting, and it is possible to appropriately suppress pitching and bouncing without reducing the drivability of the vehicle Ve.

  Here, to briefly explain the relationship between the control example shown in the flowchart and the present invention, the functional means in step S1 described above corresponds to the driving force distribution ratio calculating means of the present invention. The functional means in step S3 corresponds to the driving force detecting means of the present invention, and the functional means in steps S5 to S7 correspond to the driving force changing means of the present invention.

  In addition, in the specific example mentioned above, the example of a structure by which each in-wheel motor 9 and -12 is each installed for each wheel 1 to 4 is shown, and each in-wheel motor 9 and -12 is all independent. In the present invention, at least the driving force or braking force generated at the front wheels 1 and 2 and the rear wheels 3 and 4 can be controlled independently, that is, at least the in-wheel motor. 9 and 10 and the in-wheel motors 11 and 12 may be configured so that the rotation can be controlled independently. Further, the in-wheel motor may be configured to be installed on at least one front wheel and one rear wheel of either one of the front wheels 1 and 2 and one of the rear wheels 3 and 4.

  Further, the driving force or braking force generated at least on the front wheels 1 and 2 and the rear wheels 3 and 4 can be independently controlled, that is, the driving force generating mechanism in the present invention includes each wheel 1 as in the specific example described above. , To 4 for each in-wheel motor 9, 12 is not limited to the configuration, for example, 2 connected to the front wheels 1 and 2 and the rear wheels 3 and 4 respectively so as to be able to transmit power. A configuration may be employed in which the driving force or braking force generated on the front wheels 1 and 2 and the rear wheels 3 and 4 is independently controlled by a basic electric motor (motor generator).

1 is a conceptual diagram schematically showing a configuration and a control system of a vehicle to which a control device of the present invention can be applied. It is the figure which looked at the vehicle which can apply the control apparatus of this invention from the side, Comprising: It is a schematic diagram for demonstrating positional relationships, such as the gravity center of a vehicle, and the instantaneous rotation center of a suspension mechanism. It is a flowchart for demonstrating the example of control by the control apparatus of this invention. FIG. 10 is a schematic diagram for explaining a conventional method for calculating a driving force distribution ratio of front and rear wheels when executing control for suppressing pitching and bouncing. It is a schematic diagram for demonstrating the calculation method of the driving force distribution ratio of the front-rear wheel by the control apparatus of this invention, when performing control which suppresses pitching and bouncing.

Explanation of symbols

  1, 2, ... Front wheels, 3, 4 ... Rear wheels, 5, 6, 7, 8 ... Suspension mechanism, 9, 10, 11, 12 ... In-wheel motor (electric motor), 15, 16, 17, 18 ... Brake mechanism, DESCRIPTION OF SYMBOLS 20 ... Electronic control unit (ECU), 23 ... Vertical acceleration sensor, 24 ... Stroke sensor, Bo ... Vehicle body, Ve ... Vehicle.

Claims (3)

A suspension mechanism that supports at least the front wheel and the rear wheel independently on the vehicle body; a driving force generation mechanism that generates a driving force or a braking force independently on each of the front wheel and the rear wheel; and pitching of the vehicle body Alternatively, in order to suppress the pitching or bouncing according to the bouncing state, the driving force or braking force generated on the front wheels and the driving force or control generated on the rear wheels with respect to the total driving force required for the vehicle. Driving force distribution ratio calculating means for calculating a driving force distribution ratio that is a ratio to the power, and controlling the driving force generation mechanism based on the driving force distribution ratio to apply driving force or braking force to the front and rear wheels. In a control device for a vehicle to be generated,
In addition to the braking force generated on the front and rear wheels by the driving force generation mechanism, a braking mechanism that generates braking force independently for at least the front wheel and the rear wheel,
Driving force detection means for detecting that the driving force or the braking force generated in either one of the front and rear wheels based on the driving force distribution ratio is a value close to 0;
When the driving force detecting means detects that the driving force or braking force generated on the one wheel is a value close to 0, the braking mechanism is controlled so that a predetermined braking force is applied to the one wheel. And generating a driving force equal to or substantially equal to the predetermined braking force in addition to the driving force or braking force in the vicinity of 0 and controlling the driving force generation mechanism to generate the one of the wheels. A vehicle control device comprising a driving force changing means.   The driving force generation mechanism controls the rotation of an electric motor connected to at least the front wheel and the rear wheel so as to be able to transmit power, so that at least the front wheel and the rear wheel are independently driven with torque or braking. The vehicle control device according to claim 1, further comprising a mechanism for applying torque.   3. The vehicle control according to claim 2, wherein the electric motor includes an in-wheel motor that is supported by the vehicle body via the suspension mechanism together with the front and rear wheels, and is incorporated in the front and rear wheels respectively. apparatus.

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