Vehicle behavior control device, vehicle behavior control method, and vehicle behavior control program

Abstract

The invention relates to a vehicle behavior control device, a vehicle behavior control method and a vehicle behavior control program, and provides a technology capable of reducing cost. This vehicle behavior control device is provided with: an i-th suspension provided to an i-th wheel (i = 1, 2, 3) of four wheels of a vehicle; a fourth suspension provided to a fourth wheel other than the i-th wheel; and a controller. The i-th suspension includes an i-th actuator whose position is controlled by a controller. The controller is configured to acquire a request value for a behavior parameter that determines a behavior of the vehicle, convert the request value for the behavior parameter to an i-th request control force for an i-th wheel, calculate an i-th position control amount of an i-th actuator based on the i-th request control force, and perform position control of the i-th actuator on the basis of the i-th position control amount.

Description

Technical Field

[0001] This disclosure relates to a technique for controlling the behavior of a vehicle. Background Technology

[0002] Patent Document 1 discloses a technique for controlling the behavior of a vehicle using a small number of actuators. In particular, it discloses a technique for achieving equal control when each of the four wheels has an actuator, using actuators equipped on three of the four wheels.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2023-047810

[0004] Patent Document 1 focuses on controlling the force (torque) of each actuator. To implement force (torque) control of the actuators, at least a force sensor and a torque sensor for detecting force (torque) are required. Therefore, the cost of configuring an actuator capable of force (torque) control is relatively high. Summary of the Invention

[0005] One object of this disclosure is to provide a cost-reducing technique for vehicle behavior control, in view of the aforementioned issues.

[0006] The first aspect of this disclosure relates to a vehicle behavior control device.

[0007] The vehicle behavior control device of the first viewpoint includes: an i-th suspension, disposed on the i-th wheel (i = 1, 2, 3) of the four wheels of the vehicle; a fourth suspension, disposed on the fourth wheel other than the i-th wheel; and a controller. The i-th suspension includes an i-th actuator whose position is controlled by the controller. The controller is configured to: obtain a required value of a behavior parameter that determines the behavior of the vehicle; transform the required value of the behavior parameter into an i-th required control force for the i-th wheel; calculate an i-th position control quantity of the i-th actuator based on the i-th required control force; and perform position control of the i-th actuator according to the i-th position control quantity.

[0008] According to this disclosure, the cost of a vehicle behavior control device can be reduced. Attached Figure Description

[0009] Figure 1 This is a diagram illustrating the behavior model of the vehicle behavior control device used for vehicle behavior control in an embodiment.

[0010] Figure 2 This is a diagram used to illustrate the structure of the vehicle behavior control device in the embodiment.

[0011] Figure 3 This is a diagram illustrating an example of the structure of the actuator in an embodiment.

[0012] Figure 4 This is a diagram showing an active suspension system implemented by modeling the spring elements.

[0013] Figure 5 This is a flowchart illustrating the processes executed in the behavior control device of the first embodiment.

[0014] Figure 6 It is a flowchart representing the process performed to modify the required values ​​of behavioral parameters.

[0015] Figure 7 This is a flowchart illustrating the processes performed in the behavior control device of the second embodiment. Detailed Implementation

[0016] 1. First Implementation Method

[0017] 1.1 Vehicle Behavior Model

[0018] The vehicle behavior control device of the first embodiment controls the behavior of the vehicle based on a behavior model. Figure 1 A behavior model for controlling the behavior of a vehicle 10 using the vehicle behavior control device of the first embodiment is shown. In the behavior control of the vehicle 10, required values ​​of behavior parameters that determine the behavior of the vehicle 10 are calculated, and control is performed to achieve the calculated required values. In the first embodiment, the vertical control force for each wheel is used as the behavior parameter. Figure 1 The behavioral model shown illustrates the vertical control force F on the left rear wheel 14RL. rli The vertical control force F on the right rear wheel 14RR rri The vertical control force F on the left front wheel 14FL fli And the vertical control force F on the right front wheel 14FR. fri .

[0019] As for the behavior control of vehicle 10, various controls corresponding to the objectives are envisioned. For example, behaviors control of vehicle 10 can include sprung feedback control, unsprung feedback control, anti-sprung control, and attitude control. Sprung feedback control controls sprung vibrations based on sprung state variables calculated using measurements from a sprung acceleration sensor. Unsprung feedback control controls unsprung vibrations based on unsprung state variables calculated using measurements from both a sprung acceleration sensor and a vehicle height sensor. Anti-sprung control uses camera images and a database of high-precision map data to anticipate road conditions and suppress vibrations. Attitude control targets steering and acceleration control. Of course, combinations of these controls are also possible.

[0020] The required values ​​for the behavioral parameters are calculated in a manner that achieves the purpose of behavioral control. In this embodiment, the behavioral control can be any of the various controls described above. That is, in this embodiment, the method for calculating the required values ​​for the behavioral parameters is not particularly limited.

[0021] Furthermore, the behavior of vehicle 10 can be described by the roll moment M acting on the center of gravity of vehicle 10. r Pitch moment M p and vertical force F h The motion pattern at the sprung center of gravity position (hereinafter also referred to as "center of gravity three-mode") is represented. Therefore, the required values ​​of the behavior parameters can be transformed into the center of gravity three-mode. In particular, when the vertical control force of each wheel is used as the behavior parameter, it can be transformed into the center of gravity three-mode by the following equation (1). In equation (1), l f l r T f And T r These are the distance between the centers of gravity of the front axle, the distance between the centers of gravity of the rear axle, the front track width, and the rear track width (refer to...). Figure 1 The above parameters can be managed in advance as basic specification information for vehicle 10.

[0022]

Formula 1

[0023]

[0024] The following will refer to the transformed values ​​of the behavioral parameters into the three-mode center of gravity values ​​as the "three-mode center of gravity requirement values". Furthermore, in the three-mode center of gravity requirement values, the roll moment M will be respectively... r Pitch moment M p and vertical force F h The relevant required value is also called the required roll moment M. r Required pitching moment M p And the required vertical force F h .

[0025] exist Figure 1In the behavioral model of the vehicle 10 shown, the suspension 20RLA suspending the left rear wheel 14RL is configured as an active suspension including actuator 26RL. Furthermore, the suspension 20RRA suspending the right rear wheel 14RR is configured as an active suspension including actuator 26RR. Additionally, the suspension 20FRA suspending the right front wheel 14FR is configured as an active suspension including actuator 26FR. Suspensions 20FRA, 20RRA, and 20RLA are so-called fully active suspensions capable of actively imparting vertical control forces to wheels 14FR, 14RR, and 14RL via actuators 26FR, 26RR, and 26RL. On the other hand, the suspension 20FL suspending the front left wheel 14FL is a general suspension without actuators, i.e., a non-active suspension.

[0026] exist Figure 1 In the behavioral model shown, the control force F applied by actuator 26RL to the left rear wheel 14RL is illustrated. rl The control force F applied to the right rear wheel 14RR by actuator 26RR rr The control force F applied to the right front wheel 14FR by actuator 26FR fr Hereinafter, wheels equipped with active suspension will be specifically referred to as "control wheels." That is, in... Figure 1 In the behavioral model shown, the left rear wheel 14RL, the right rear wheel 14RR, and the right front wheel 14FR are the control wheels.

[0027] The inventors of this disclosure have discovered that the required values ​​of the three-mode center of gravity can be transformed into control forces for each control wheel by the following formula (2).

[0028]

Formula 2

[0029]

[0030] As described above, the required values ​​of the behavior parameters can be transformed into required values ​​for the three-mode center of gravity, thus transforming the required values ​​of the behavior parameters into control forces for each controlled wheel. Hereinafter, the control forces for each controlled wheel obtained through the transformation of the required values ​​of the behavior parameters will also be referred to as "required control forces." Furthermore, by controlling each actuator 26RL, 26RR, and 26FR in a manner that satisfies the required control forces, the required values ​​of the behavior parameters can be achieved. That is, the desired vehicle behavior can be achieved using only three actuators 26RL, 26RR, and 26FR. Reducing the number of required actuators is preferable from the viewpoints of improved installation compatibility, cost reduction, weight reduction, and energy saving.

[0031] Alternatively, the behavior control of the vehicle 10 described above can be achieved through "torque control" of each actuator 26RL, 26RR, and 26FR. In the case of torque control, force sensors, torque sensors, etc., are required. Therefore, in order to further reduce installation space and cost, this embodiment proposes a method for achieving the above-mentioned behavior control through "position control" of each actuator 26RL, 26RR, and 26FR. The following describes in detail the vehicle behavior control device that controls the behavior of the vehicle 10 through position control of each actuator 26RL, 26RR, and 26FR.

[0032] 1.2 Vehicle Behavior Control Device

[0033] Figure 2 This is a diagram used to explain the structure of the vehicle behavior control device according to the first embodiment.

[0034] exist Figure 2 In this vehicle 10, the front axle 16F has a left front wheel 14FL and a right front wheel 14FR that serve as steering wheels, and the rear axle 16R has a left rear wheel 14RL and a right rear wheel 14RR that serve as non-steering wheels. Alternatively, steering mechanisms may also be provided on the rear wheels 14RL and 14RR. Furthermore, the vehicle 10 can be a front-wheel drive vehicle that drives the front wheels 14FL and 14FR, a rear-wheel drive vehicle that drives the rear wheels 14RL and 14RR, or an all-wheel drive vehicle that drives both the front wheels 14FL and 14FR and the rear wheels 14RL and 14RR.

[0035] The vehicle behavior control device includes: a suspension 20RLA (hereinafter also referred to as "first suspension 20RLA") installed on the left rear wheel 14RL (first wheel); a suspension 20RRA (hereinafter also referred to as "second suspension 20RRA") installed on the right rear wheel RR (second wheel); a suspension 20FRA (hereinafter also referred to as "third suspension 20FRA") installed on the right front wheel 14FR (third wheel); a suspension 20FL (hereinafter also referred to as "fourth suspension 20FL") installed on the left front wheel 14FL (fourth wheel); a controller 30; and a sensor group 40. As described above, the first suspension 20RLA, the second suspension 20RRA, and the third suspension 20FRA are active suspensions, and the fourth suspension 20FL is a non-active suspension.

[0036] The fourth suspension 20FL, which is a non-active suspension, has a spring 22FL and a shock absorber 24FL. The first suspension 20RLA, which is an active suspension, has an actuator 26RL (hereinafter also referred to as "the first actuator 26RL") in addition to the spring 22RL and the shock absorber 24RL.

[0037] Similarly, the second suspension 20RRA, which is an active suspension, has an actuator 26RR (hereinafter also referred to as "the second actuator 26RR") in addition to the spring 22RR and the shock absorber 24RR. Similarly, the third suspension 20FRA, which is an active suspension, has an actuator 26FR (hereinafter also referred to as "the third actuator 26FR") in addition to the spring 22FR and the shock absorber 24FR.

[0038] The controller 30 is connected to the sensor group 40 via an in-vehicle network such as CAN (Controller Area Network). The controller 30 obtains signals from the sensor group 40. The sensor group 40 includes, for example, sensors that measure physical quantities related to the behavior of the vehicle 10, such as acceleration sensors, vehicle height sensors, and wheel speed sensors. In addition, the controller 30 is also connected to each actuator 26RL, 26RR, and 26FR via the in-vehicle network.

[0039] The controller 30 includes a processor 32 and a memory 34 associated with the processor 32.

[0040] Processor 32 performs various processes. Processor 32 can be, for example, composed of a CPU (Central Processing Unit), GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), etc., which includes arithmetic units and registers. Memory 34 stores various information required for performing processes based on processor 32. Memory 34 can be, for example, composed of recording media such as ROM (Read Only Memory), RAM (Random Access Memory), HDD (Hard Disk Drive), SSD (Solid State Drive).

[0041] The memory 34 stores a computer program 36 that can be executed by the processor 32, and various information related to the computer program 36. The processor 32 executing the computer program 36, in conjunction with the memory 34, enables the function of the controller 30. The computer program 36 can be recorded on a computer-readable recording medium. Alternatively, the computer program 36 can also be distributed via OTA (Over-The-Air) technology.

[0042] The controller 30 controls each actuator 26RL, 26RR, and 26FR based on signals obtained from the sensor group 40. Specifically, the controller 30 calculates the position control amount for each actuator 26RL, 26RR, and 26FR through the execution of processing, and sends the calculated position control amount to each actuator 26RL, 26RR, and 26FR. That is, the controller 30 performs position control for each actuator 26RL, 26RR, and 26FR. The position control amount can provide a target position or a movement amount from the current position. Details of the processing performed by the controller 30 in the first embodiment will be described later.

[0043] Each actuator 26RL, 26RR, and 26FR operates according to the position control quantity received from the controller 30. Each actuator 26RL, 26RR, and 26FR is configured to vary the control force applied to the corresponding control wheel according to the controlled position.

[0044] Such actuators can be designed to accommodate various configurations. Figure 3 This is a diagram illustrating an example of the structure of the actuator 26 in the first embodiment. Figure 3 The active suspension 20A, including actuator 26, is shown in the figure.

[0045] exist Figure 3 In the active suspension 20A shown, spring 22 and damper 24 are disposed between vehicle body 12 and unsprung component 21 (e.g., suspension arm). Spring 22 generates a reaction force corresponding to the travel of active suspension 20A.

[0046] Figure 3 The actuator 26 shown includes a motor 28 supported on a spring-loaded structure and a torsion bar 27 with one end connected to the output shaft of the motor 28. The other end of the torsion bar 27 is connected to the unsprung component 21 via a linkage mechanism 29. The operation of the motor 28 is controlled by a controller 30. In particular, in this embodiment, the controller 30 performs position control of the motor 28. Therefore, in this case, the position of the actuator 26 represents the angle of the motor 28. Furthermore, the position control quantity is the target angle or rotation angle of the motor 28.

[0047] If the motor 28 rotates under the control of the controller 30, the torsion bar 27 deforms, and the reaction force of the torsion bar 27 is converted into a vertical force via the linkage mechanism 29 and transmitted to the unsprung component 21 and the wheel 14. Thus, the actuator 26 can actively apply vertical control force to the unsprung component 21 and the wheel 14 by deforming the torsion bar 27. Furthermore, during acceleration, deceleration, and steering operations of the vehicle 10, the external force input from the unsprung component 21 side is transmitted to the output shaft of the motor 28 via the linkage mechanism 29 and the torsion bar 27. The torsion bar 27 and the linkage mechanism 29 can also be considered as force transmission components between the motor 28 and the unsprung component 21 and the wheel 14.

[0048] The actuator 26 of this embodiment can be configured as described above. The vehicle behavior control device of this embodiment can... Figure 3 The structure of actuator 26 described herein applies to each of actuators 26RL, 26RR, and 26FR. Among them, Figure 3 The structure of actuator 26 described herein is one example, but other structures can also be applied.

[0049] For example, actuator 26 may also consist of a coil spring connected at one end to unsprung component 21 and a linear motor that actuates by extending or contracting the coil spring. In this case, if the linear motor is actuated by controller 30, the coil spring deforms, and the reaction force of the coil spring is transmitted to unsprung component 21 and wheel 14. The coil spring can also be considered a force transmission component between the linear motor and unsprung component 21 and wheel 14. Furthermore, in this case, the position of actuator 26 may refer to, for example, the position on the guide of the movable part of the linear motor. The position control quantity may be, for example, the target position or the amount of movement on the guide of the movable part.

[0050] Alternatively, actuator 26 may consist of a motor supported on a sprung structure, a ball screw nut that rotates via the motor's output, a ball screw shaft that moves axially via the rotation of the ball screw nut, and a piston rod connected at one end to the ball screw shaft. The other end of the piston rod is connected to the unsprung component 21 via a cylinder. In this case, if the motor rotates under the control of controller 30, the ball screw nut rotates, and the axial force based on the ball screw shaft and piston rod is transmitted to the unsprung component 21 and wheel 14. The ball screw nut, ball screw shaft, and piston rod can also be considered as force transmission components between the motor and the unsprung component 21 and wheel 14.

[0051] Furthermore, the transmission components such as the torsion bar 27 can be considered as elastic components with a specified rigidity. Additionally, it is possible that the motor 28 is fastened to part of the vehicle body 12, suspension components, etc. Therefore, Figure 3 The actuator 26 shown can be modeled as a spring element connected in parallel with the spring 22.

[0052] Figure 4 This is a diagram showing the active suspension 20A after the spring elements have been modeled. Figure 4 In the diagram, Ks represents the stiffness of spring 22, and Kb represents the stiffness of torsion bar 27. Additionally, z1 and z2 represent the unsprung and supinated displacements, respectively, with the upward direction shown in the attached diagram as the positive direction. That is, in Figure 4 In the model shown, z2-z1 represent the travel of the active suspension 20A. Furthermore, in the following description, it is also possible to replace the torsion bar 27 with other transmission components based on the structure of the actuator 26.

[0053] The spring element of the torsion bar 27 generates at least a reaction force corresponding to the amount of travel. Furthermore, it can be assumed that the spring element of the torsion bar 27 generates a reaction force corresponding to the relative displacement zΔ based on the position control of the actuator 26. Figure 4 In the model shown, zΔ takes the direction of the spring element's extension as positive. Figure 4 In the model shown, the force F generated by actuator 26 is represented by the following equation (3). The force F is equivalent to the control force applied to wheel 14 by actuator 26. Even if the position command for actuator 26 (motor 28) is zero, that is, even if the relative displacement zΔ is zero, actuator 26 generates a force F corresponding to the stroke amount (z2-z1).

[0054]

Formula 3

[0055]

[0056] 1.3 Behavioral Control

[0057] Hereinafter, the processing performed by the controller 30 in the behavior control of the vehicle 10 in the first embodiment, and more specifically, the processing performed by the processor 32, will be described. Figure 5 This is a flowchart illustrating an example of the processing performed by the controller 30 in the first embodiment. Figure 5 The flowchart shown can be executed repeatedly at a specified processing cycle.

[0058] In step S110, the controller 30 calculates the required value of the behavior parameter. Alternatively, the controller 30 may obtain the required value of the behavior parameter from another device. In the first embodiment, the behavior parameter is the control force in the vertical direction for each wheel. That is, in step S110, the controller 30 calculates (obtains) the vertical control force F for the left rear wheel RL. rli The vertical control force F of the right rear wheel RE rri The vertical control force F of the left front wheel FL fli And the vertical control force F of the right front wheel FR. friEach has its own required value. As mentioned above, in this embodiment, the method for calculating the required values ​​of the behavioral parameters is not particularly limited.

[0059] Next, in step S120, the controller 30 transforms the required values ​​of the behavior parameters into the required values ​​of the three-mode center of gravity. The controller 30 can transform the required values ​​of the behavior parameters into the required roll moment M using the above equation (1). r Required pitching moment M p And the required vertical force F h .

[0060] Next, in step S130, the controller 30 further transforms the required values ​​of the three center of gravity modes into the required control forces for each controlled wheel. The controller 30 uses the above equation (2) to convert the required roll moment M... r Required pitching moment M p And the required vertical force F h Transformed into the required control force F for the left rear wheel 14RL rl (Hereinafter also referred to as "first required control force") Required control force F for the right rear wheel 14RR rr (Hereinafter also referred to as "Second Required Control Force") and the required control force F for the right front 14FR wheel. fr (Hereinafter also referred to as "the third requirement of control").

[0061] Next, in step S140, the controller 30 calculates the travel amount of the first suspension 20RLA (first required travel amount), the travel amount of the second suspension 20RRA (second required travel amount), and the travel amount of the third suspension 20FRA (third required travel amount) when the required values ​​of the behavior parameters are met. Each required travel amount can be considered as the travel amount that each active suspension should meet in the behavior control of the vehicle 10.

[0062] The vertical control force of each wheel is proportional to the travel of each suspension element, therefore the travel of each suspension element can be calculated using the following equation (4). Here, z srl z srr z sfr and z sfl These are the travel amounts of the first suspension (20RLA), the second suspension (20RRA), the third suspension (20FRA), and the fourth suspension (20FL). Additionally, K... r and K f These are the proportional constants related to the rear axle 16R and the front axle 16F, respectively. K r and K f It is a constant that can be determined based on the basic specifications of vehicle 10 and the state of vehicle 10.

[0063]

Formula 4

[0064]

[0065] Therefore, the controller 30 uses equation (4) to calculate F based on the required value as a behavior parameter. rli Required value, F rri Required values ​​and F fri Calculation of the first required stroke z srl The second requirement is the travel distance z. srr And the third requirement is the travel distance z. sfl .

[0066] Next, in step S150, the controller 30 calculates the position control quantities of each actuator 26RL, 26RR, and 26FR that satisfy the required control force for each controlled wheel. That is, the controller 30 calculates the position control quantity (first position control quantity) of the first actuator 26RL corresponding to the first required control force, the position control quantity (second position control quantity) of the second actuator 26RR corresponding to the second required control force, and the position control quantity (third position control quantity) of the third actuator 26FR corresponding to the third required control force. The controller 30 then calculates the required stroke amount (first required stroke amount z) based on the calculations made in step S140. srl The second requirement is the travel distance z. srr And the third requirement is the travel distance z. sfl It can calculate the first position control value, the second position control value, and the third position control value as follows.

[0067] like Figure 4 As explained above, the control force applied to the wheel 14 by the actuator 26 can be expressed by equation (3) based on the stroke amount and the relative displacement based on position control. Therefore, the controller 30 can, by using equation (3), determine the first required stroke amount z. srl Calculate the first required control force F rl The relative displacement of the first actuator 26RL (hereinafter also referred to as the "first required relative displacement"). The first required stroke amount z srl Substituting z2-z1 into equation (3), the first required control force F rl Substituting the force F, we can obtain the first requirement: relative displacement zΔ rl It is represented by the following formula (5).

[0068]

Formula 5

[0069]

[0070] Similarly, by using equation (3), the controller 30 can determine the second required stroke amount z. srrand the third requirement for travel distance z sfl Calculate the second required control force F rr The relative displacement of the second actuator 26RR (hereinafter also referred to as the "second required relative displacement") zΔ rr and subject to the third requirement of control F fr The relative displacement of the third actuator 26FR (hereinafter also referred to as the "third required relative displacement") zΔ fr .

[0071] In addition, Figure 4 In the model shown, the relative displacement zΔ is a quantity that corresponds to the position of the actuator 26. That is, if the correspondence between the relative displacement zΔ and the position of the actuator 26 is known, then the relative displacement zΔ can be converted into the position of the actuator 26.

[0072] The correspondence between the relative displacement zΔ and the position of actuator 26 can be determined based on the design value of the active suspension 20A and the measured value based on experiments. For example, when actuator 26 is Figure 3 In the structure shown, it is possible to rotate the motor 28 while the vehicle 10 is stationary, and measure the angle θ of the motor 28 (position of the actuator 26) and the travel z of the active suspension 20A. s The experimental results show that the coefficient A of equation (6) can be calculated through this experiment. Furthermore, the relationship in equation (7) holds true at this time.

[0073]

Formula 6

[0074]

[0075] Therefore, by using the experimental determination coefficient A, the correspondence between the relative displacement zΔ and the angle θ of the motor 28 (position of the actuator 26) can be expressed by the following equation (8). That is, the relative displacement zΔ can be converted into the angle of the motor 28 (position of the actuator 26) by equation (8).

[0076]

Formula 7

[0077]

[0078] The correspondence between the relative displacement zΔ and the position of the actuator 26 can be stored in memory 34 as a function or mapping information. Alternatively, it can be recorded as part of the computer program 36.

[0079] Thus, based on the correspondence between the relative displacement zΔ and the position of the actuator 26, the controller 30 can determine the first required relative displacement zΔ. rlThe position is converted to that of the first actuator 26RL. Furthermore, the controller 30 calculates the first position control quantity by indicating the converted position of the first actuator 26RL. Similarly, the controller 30 can also calculate the second required relative displacement zΔ. rr And the third requirement is the relative displacement zΔ fr The positions are converted to the positions of the second actuator 26RR and the third actuator 26FR, respectively. Furthermore, the controller 30 calculates the second and third position control values ​​by indicating the converted positions of the second actuator 26RR and the third actuator 26FR.

[0080] Thus, the controller 30 can calculate the first position control quantity, the second position control quantity, and the third position control quantity based on each required stroke quantity, so as to obtain the required control force for each controlled wheel.

[0081] Next, in step S160, the controller 30 performs position control of the first actuator 26RL, the second actuator 26RR, and the third actuator 26FR based on the calculated first position control value, second position control value, and third position control value. This allows the first required control force F to be satisfied. rl The second requirement is to control force F. rr And the third requirement is control force F fr The actuators 26RL, 26RR, and 26FR are controlled in this manner. This allows the required values ​​for the behavioral parameters to be achieved. After step S160, the controller 30 terminates this process.

[0082] By executing the processing in this way by the controller 30, the function of the vehicle behavior control device of the first embodiment is realized. Furthermore, by executing the processing in this way by the controller 30, the vehicle behavior control method of the first embodiment is realized. Additionally, by executing the processing in this way by the computer program 36 that causes the controller 30 to perform the processing, the vehicle behavior control program of the first embodiment is realized.

[0083] 1.4 Correction of Required Value

[0084] exist Figure 3 In the example shown, each actuator 26RL, 26RR, and 26FR includes a transmission component such as a torsion bar 27 that transmits the reaction force generated by deformation as a control force. Furthermore, each actuator 26RL, 26RR, and 26FR applies a vertical control force to each control wheel by deforming the transmission component. Figure 3In the structure shown, for each actuator 26RL, 26RR, and 26FR, even if the relative displacement zΔ is zero, a control force corresponding to the magnitude of the reaction force of the transmission component is output. For example, when the vehicle 10 turns or accelerates / decelerates, a stroke is generated. Therefore, even if the relative displacement zΔ is zero, each actuator 26RL, 26RR, and 26FR outputs a control force corresponding to the magnitude of the reaction force of the transmission component.

[0085] On the other hand, in the vehicle behavior control device of the first embodiment, the fourth suspension 20FL installed on the left front wheel 14FL does not include an actuator. That is, the fourth suspension 20FL does not include transmission components such as the torsion bar 27. Therefore, the fourth suspension 20FL does not generate a reaction force equivalent to the reaction force generated in other suspensions that corresponds to the reaction force of the transmission components. This may cause problems with the attitude of the vehicle 10 during steering and acceleration / deceleration. This means that the suspension 20FL of the left front wheel 14FL is "softer" compared to the suspensions 20FR, 20RL, and 20RR of the other wheels 14FR, 14RL, and 14RR. That is, an imbalance in suspension stiffness occurs between the left front wheel 14FL and the other wheels 14FR, 14RL, and 14RR. Such an imbalance in suspension stiffness becomes a cause of abnormal and uncoordinated body roll during acceleration, deceleration, and steering. In addition, the imbalance in suspension stiffness can lead to decreased control performance, excessive oversteer, or understeer.

[0086] For example, consider the case where the relative displacement required for each actuator 26RL, 26RR, and 26FR is zero when the vehicle 10 decelerates by braking. In this case, the suspension output transmission components other than the fourth suspension 20FL have a control force to control the magnitude of the reaction force, so the travel is small. On the other hand, the fourth suspension 20FL does not generate a reaction force equivalent to the reaction force of the transmission components, so the travel is large. As a result, the left front wheel 14FL sinks significantly compared to the other wheels, and the vehicle 10 may tilt in a lateral direction. Furthermore, for example, when the vehicle 10 is turning, such as when turning right, the left front wheel 14FL sinks significantly, while on the other hand, when turning left, the right front wheel 14FR does not sink as much as the left front wheel 14FL when turning right, and so on, it is possible that the posture of the vehicle 10 will differ depending on the direction of the turn.

[0087] To address the aforementioned issues, in the vehicle behavior control device of this embodiment, it may be assumed that the fourth suspension 20FL includes a transmission component such as a torsion bar 27, and the required values ​​of the behavior parameters may be modified. That is, the required values ​​of the behavior parameters are modified to achieve the behavior of the vehicle 10 that can be considered as generating a reaction force of the transmission component in the fourth suspension 20FL. The modification of the required values ​​of the behavior parameters can be based on a virtual reaction force value applied to the left front wheel 14FL by assuming it is a transmission component included in the fourth suspension 20FL.

[0088] Here, the virtual reaction force value, for example when the transmission component is a torsion bar 27, can be calculated as follows.

[0089] First, regarding acceleration and deceleration, the suspension-shared force F of the left front wheel 14FL, excluding the suspension linkage reaction force, is calculated using the following formula (9). flx .

[0090]

Formula 8

[0091]

[0092] Here, the parameters are defined as follows.

[0093] H: Height of the sprung center of gravity

[0094] l: wheelbase

[0095] m: Sprout mass

[0096] a xp Acceleration side of front and rear G

[0097] a xm : Deceleration side of front and rear G

[0098] α xp Front drive force distribution

[0099] α xm Front braking force distribution

[0100] α k Regeneration ratio at the front

[0101] tanθ I Suspension link camber angle in a lateral view relative to the wheel center (point I).

[0102] tanθ J Suspension link inclination angle in a lateral view relative to the tire contact point (point J).

[0103] Furthermore, in equation (9) above, the driving force and regenerative force act on point I. Additionally, the front and rear G of the vehicle 10 can be inferred based on the required torque, required force, braking, and regenerative force of the engine and drive motor. Alternatively, it can be obtained through sensors.

[0104] Next, regarding steering control, the suspension-shared force F of the left front wheel 14FL, excluding the suspension linkage reaction force, is calculated using the following equation (10). fly .

[0105]

Formula 9

[0106]

[0107] The parameters are defined as follows.

[0108] β: Vehicle slip angle

[0109] V: Vehicle speed

[0110] r: Yaw rate

[0111] γ: Front axle load transfer ratio

[0112] a y :Horizontal G

[0113] C pf Front wheel cornering ability

[0114] tanθ y Rearward view of suspension link camber angle

[0115] The lateral G of vehicle 10 can be inferred from factors such as steering angle and vehicle speed. Alternatively, it can be obtained through sensors.

[0116] Based on the aforementioned suspension load distribution F of the left front wheel 14FL related to acceleration and deceleration flx The suspension load F on the left front wheel (14 FL) related to steering control. fly The virtual reaction force value can be calculated using the following equation (11). Here, K bf The assumed stiffness of torsion bar 27 (including bushing effects and connecting rod efficiency), K sf It is the upper and lower stiffness of the suspension (excluding the stiffness of the torsion bar 27).

[0117]

Formula 10

[0118]

[0119] In the first embodiment, the required value of the behavior parameter is the required value of the control force in the vertical direction for each wheel. Therefore, in the first embodiment, the required value of the behavior parameter can be corrected by adding the virtual reaction force value calculated by equation (11) to the required value of the control force in the vertical direction for the left front wheel FL. That is, in the corrected required value of the behavior parameter, the required value of the control force in the vertical direction for the left front wheel FL is F' of the following equation (12). rli In equation (12), F represents... rli This indicates the required value before the correction.

[0120]

Formula 11

[0121]

[0122] Controller 30 can be configured to calculate the required values ​​of behavioral parameters ( Figure 5 After step S110), execute Figure 6 The flowchart shown illustrates the processing.

[0123] In step S111, the controller 30 assumes that the fourth suspension 20FL includes transmission components such as the torsion bar 27, and calculates the virtual reaction force value applied to the left front wheel FL by means of the transmission components assumed to be included in the fourth suspension 20FL. For example, the controller 30 can calculate the virtual reaction force value using the above equations (9)-(11).

[0124] Next, in step S112, the controller 30 corrects the required value of the behavior parameter based on the calculated virtual reaction force value. In the first embodiment, as shown in equation (12), the controller 30 corrects the required value of the behavior parameter by adding the virtual reaction force value and the required value of the control force in the vertical direction for the left front wheel FL.

[0125] After step S112, the process can proceed to... Figure 5 Step S120. At this point, the required value of the behavior parameter becomes the corrected required value.

[0126] 1.5 Effects

[0127] As explained above, according to the first embodiment, regarding the behavior control of the four-wheeled vehicle 10, the same level of controllability as when active suspensions are installed on each wheel can be achieved through the three active suspensions 20RLA, 20RRA, and 20FRA. This reduces the number of actuators required, thus improving portability, reducing costs, lowering weight, and saving energy. Furthermore, according to the first embodiment, each actuator 26RL, 26RR, and 26FR is controlled by position control. That is, force sensors, torque sensors, etc., are no longer needed, which reduces the space and cost of mounting each actuator 26RL, 26RR, and 26FR. This further improves portability and reduces costs.

[0128] Furthermore, in the above embodiment, the suspension 20FL installed on the left front wheel 14FL is set to be a non-active suspension. However, in the vehicle behavior control device of the first embodiment, it is possible to arbitrarily determine which three wheels out of the four wheels are equipped with active suspension. For example, it is also possible to set the suspension 20RRA installed on the right rear wheel 14RR to be a non-active suspension, and set the suspensions 20RLA, 20FL, and 20FRA installed on the other wheels 14RL, 14FL, and 14FR to be active suspensions.

[0129] 2. Second Implementation Method

[0130] The vehicle behavior control device according to the second embodiment will be described below. In the following description, the differences from the first embodiment will be explained, and common content with the first embodiment will be omitted as appropriate.

[0131] 2.1 Behavioral Control

[0132] The vehicle behavior control device of the second embodiment controls the behavior of the vehicle 10 in the same way as the first embodiment. Figure 1 The behavior model shown is used. In the second embodiment, a three-mode center of gravity is used as the behavior parameter. That is, the required value of the behavior parameter in the second embodiment is the required roll moment M. r Required pitching moment M p And the required vertical force F h The required values ​​of the behavioral parameters directly become the required values ​​of the three-mode center of gravity.

[0133] The structure of the vehicle behavior control device in the second embodiment can be the same as... Figure 2 The structure described herein is equivalent. Hereinafter, the processing performed by the controller 30 in the behavior control of the vehicle 10 in the second embodiment, and more specifically, the processing performed by the processor 32, will be described. Figure 7 This is a flowchart illustrating an example of the processing performed by the controller 30 in the second embodiment. Figure 7The flowchart shown can be executed repeatedly at a specified processing cycle.

[0134] In step S210, the controller 30 calculates the required values ​​for the behavior parameters. Alternatively, the controller 30 may obtain the required values ​​for the behavior parameters from other devices. In the second embodiment, the behavior parameters are determined by the roll moment M. r Pitch moment M p and vertical force F h The three-mode center of gravity is formed. That is, in step S210, the controller 30 calculates (obtains) the required roll moment M. r Required pitching moment M p And the required vertical force F h Similar to the first embodiment, the method for calculating the required values ​​of the behavioral parameters is not particularly limited.

[0135] Next, in step S230, the controller 30 transforms the required values ​​for the three center of gravity modes into required control forces for each controlled wheel. The processing in step S230 and... Figure 5 The processing of step S130 described herein is equivalent.

[0136] Next, in step S240, the controller 30 calculates the first required stroke, the second required stroke, and the third required stroke when the required values ​​of the behavior parameters are met.

[0137] As explained in the first embodiment, the travel of each suspension can be calculated using the above-described formula (4) based on the control force for each wheel. On the other hand, in the second embodiment, the required value of the behavior parameter is the required value for the three-mode center of gravity. Therefore, the controller 30 first transforms the required value of the three-mode center of gravity into the control force for each wheel using the following formula (13). Hereinafter, the value of the control force for each wheel obtained by transforming the required value of the three-mode center of gravity will be referred to as the "transformed required value". In formula (13), F... rlz It is the change requirement value related to the control force on the left rear wheel, F. rrz It is the change requirement value related to the control force on the right rear wheel, F. flz It is the change requirement value related to the control force on the left front wheel, F. frz It is a change requirement value related to the control force on the right front wheel.

[0138]

Formula 12

[0139]

[0140] Furthermore, the controller 30 is able to calculate the first required stroke amount z using the following equation (14). srl The second requirement is the travel distance z. srr And the third requirement is the travel distance z.sfl .

[0141]

Formula 13

[0142]

[0143] Next, in step S250, the controller 30 calculates the position control quantities of each actuator 26RL, 26RR, and 26FR that satisfy the required control force for each controlled wheel. The processing in step S230 and... Figure 5 The processing of step S150 described herein is equivalent.

[0144] Next, in step S260, the controller 30 performs position control of the first actuator 26RL, the second actuator 26RR, and the third actuator 26FR based on the calculated first, second, and third position control values. This achieves the required values ​​for the behavioral parameters. After step S260, the controller 30 terminates this processing.

[0145] By executing the processing in this way by the controller 30, the function of the vehicle behavior control device of the second embodiment is realized. Furthermore, by executing the processing in this way by the controller 30, the vehicle behavior control method of the second embodiment is realized. Additionally, by executing the processing in this way by the computer program 36, the vehicle behavior control program of the second embodiment is realized.

[0146] 2.2 Correction of Required Value

[0147] In the second embodiment, similarly to the first embodiment, it is also possible to assume that the fourth suspension 20FL includes transmission components such as the torsion bar 27, and to adjust the required values ​​of the behavior parameters. Similarly to the first embodiment, the adjustment of the required values ​​of the behavior parameters can be based on a virtual reaction force value applied to the left front wheel 14FL by the transmission components included in the fourth suspension 20FL. The virtual reaction force value F flxy It can be calculated using the above formulas (9)-(11).

[0148] In the second embodiment, the required value of the behavioral parameter is the required roll moment M. r Required pitching moment M p And the required vertical force F h Therefore, in the second embodiment, the virtual reaction force value F is first expressed by the following equation (15). flxy The system shifts to a three-mode center of gravity. The following will use a virtual reaction force value F... flxy The value of the three-mode center of gravity obtained by the transformation is called the "transformation reaction force value". In equation (15), M rflxy It is the transformed reaction force value related to the roll moment, M. pflxyIt is the transformed reaction force value related to the pitching moment, F. hflxy It is the value of the transformed reaction force related to the vertical force.

[0149]

Formula 14

[0150]

[0151] Furthermore, the required values ​​of the behavior parameters can be modified by using the transformed reaction force value obtained through equation (16) and the required roll moment M. r Required pitching moment M p And the required vertical force F h They are added together. That is, in the required values ​​of the modified behavior parameters, the required roll moment, required pitch moment, and required vertical force are respectively expressed as M' of the following equation (16). r M' p and F' h In equation (15), M represents... r M p and F h These are the original roll moment, pitch moment, and vertical force.

[0152]

Formula 15

[0153]

[0154] Similar to the first embodiment, the controller 30 can be configured to calculate the required value of the behavioral parameters ( Figure 7 After step S210), execute Figure 6 The flowchart shown is used for processing. In the second embodiment, in step S112, as shown in equations (15)-(16), the controller 30 calculates the transformed reaction force value after converting the virtual reaction force value into the transformed reaction force value after the center of gravity three-mode, and combines the transformed reaction force value with the required roll moment M. r Required pitching moment M p And the required vertical force F h The values ​​are added together to correct the required values ​​of the behavioral parameters. After step S112, the process can proceed to... Figure 7 Step S230. At this point, the required value of the behavior parameter becomes the corrected required value.

[0155] 2.5 Effects

[0156] As can be understood from the above description, the second embodiment can also play the same role and effect as the first embodiment.

[0157] The embodiments have been described in detail above, but these embodiments are merely specific examples illustrating the implementation of the technology disclosed herein. Therefore, the scope of the technology disclosed herein is not limited to the above embodiments. The technology disclosed herein can be modified in various ways without departing from its spirit, and these modifications are also included within the scope of the technology disclosed herein.

[0158] Explanation of reference numerals in the attached figures

[0159] 10…vehicle; 30…controller; 32…processor; 34…memory; 36…computer program; 20RLA…first suspension; 20RRA…second suspension; 20FRA…third suspension; 20FL…fourth suspension; 26RL…first actuator; 26RR…second actuator; 26FR…third actuator; 27…torsion bar.

Claims

1. A vehicle behavior control device, wherein, have: The i-th suspension is installed on the i-th wheel of the vehicle's four wheels, where i = 1, 2, 3; The fourth suspension is located on the fourth wheel other than the i-th wheel; and Controller The i-th suspension includes an i-th actuator whose position is controlled by the controller. The controller is configured as follows: Obtain the required values ​​of the behavioral parameters that determine the behavior of the vehicle. The required value of the behavioral parameter is transformed into the required control force for the i-th wheel. Calculate the i-th position control quantity of the i-th actuator based on the i-th required control force. The position control of the i-th actuator is performed according to the i-th position control value.

2. The vehicle behavior control device according to claim 1, wherein, The fourth suspension does not include actuators controlled by the controller.

3. The vehicle behavior control device according to claim 1, wherein, The controller is further configured as follows: Calculate the i-th required travel of the i-th suspension when the required value of the behavioral parameter is satisfied. The i-th position control quantity is calculated based on the i-th required stroke quantity in order to obtain the i-th required control force.

4. The vehicle behavior control device according to claim 3, wherein, The behavioral parameters are the control forces for each of the i-th wheel and the fourth wheel. The controller is further configured as follows: Calculate the i-th required travel of the i-th suspension, which is equivalent to the required value related to the control force for the i-th wheel.

5. The vehicle behavior control device according to claim 3, wherein, The behavioral parameters are the roll moment, pitch moment, and vertical force acting on the vehicle's center of gravity. The controller is further configured as follows: The required values ​​related to the roll moment, the pitch moment, and the vertical force are transformed into transformed required values ​​related to the control force for each of the i-th wheel and the fourth wheel. Calculate the i-th required travel of the i-th suspension, which is equivalent to the transformation requirement value related to the control force for the i-th wheel.

6. The vehicle behavior control device according to any one of claims 1 to 5, wherein, The i-th actuator includes a transmission component that transmits the reaction force generated by deformation as a control force. The i-th actuator is configured to apply vertical control force to the i-th wheel by deforming the transmission component.

7. The vehicle behavior control device according to claim 6, wherein, The transmission component is a torsion bar.

8. The vehicle behavior control device according to claim 6, wherein, The fourth suspension does not include the actuator controlled by the controller. The controller is further configured as follows: Assuming the fourth suspension includes the transmission component, calculate the virtual reaction force value applied to the fourth wheel by the transmission component assumed to be included in the fourth suspension. The required value is adjusted based on the virtual reaction force value.

9. The vehicle behavior control device according to claim 8, wherein, The behavioral parameters are the control forces for each of the i-th wheel and the fourth wheel. The controller is further configured as follows: The required value is corrected by adding the required value related to the control force for the fourth wheel and the virtual reaction force value.

10. The vehicle behavior control device according to claim 8, wherein, The behavioral parameters are the roll moment, pitch moment, and vertical force acting on the vehicle's center of gravity. The controller is further configured as follows: The virtual reaction force value is transformed into a transformed reaction force value related to the roll moment, the pitch moment, and the vertical force. The required value is corrected by adding the required value related to the roll moment, the pitch moment, and the vertical force, and the change reaction force value.

11. A vehicle behavior control method, wherein the behavior of a vehicle is controlled by a computer, wherein, The vehicle has the following features: The i-th suspension is located on the i-th wheel of the four wheels, where i = 1, 2, 3; and The fourth suspension is located on the fourth wheel, other than the i-th wheel. The i-th suspension includes an i-th actuator that is position-controlled. The vehicle behavior control method includes the following steps: Obtain the required values ​​of the behavioral parameters that determine the behavior of the vehicle; Transform the required value of the behavior parameter into the required control force for the i-th wheel; Calculate the i-th position control amount of the i-th actuator based on the i-th required control force; as well as The position control of the i-th actuator is performed according to the i-th position control value.

12. A vehicle behavior control program that enables a computer to control the behavior of a vehicle, wherein, The vehicle has the following features: The i-th suspension is located on the i-th wheel of the four wheels, where i = 1, 2, 3; and The fourth suspension is located on the fourth wheel, other than the i-th wheel. The i-th suspension includes an i-th actuator that is position-controlled. The vehicle behavior control program causes the computer to perform the following processes: Obtain the required values ​​of the behavioral parameters that determine the behavior of the vehicle; Transform the required value of the behavior parameter into the required control force for the i-th wheel; Calculate the i-th position control quantity of the i-th actuator based on the i-th required control force; and The position control of the i-th actuator is performed according to the i-th position control quantity.

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