Road surface inclination detection method and vehicle control method

Abstract

The present invention provides a road surface inclination detection method and a vehicle control method that can appropriately detect the inclination state of the road surface on which a vehicle is traveling and are applicable to a vehicle control method. [Solution] The road surface inclination state detection method is applicable to a vehicle control method and comprises: an acquisition step of acquiring a vehicle state in which a pitching moment is applied to the vehicle 1 such that the front wheels 32 of the vehicle 1 move vertically upward relative to the rear wheels 42 of the vehicle 1, and the rear suspension 40 that suspends the rear wheels 42 is in a compression stroke; a counting step of starting counting after the vehicle state acquired in the acquisition step satisfies predetermined conditions and continuing counting until the vehicle state no longer satisfies predetermined conditions; and an inclination state detection step of detecting the inclination state of the road surface R on which the vehicle 1 is traveling according to the count value counted in the counting step.

Description

Technical Field

[0001] The present invention relates to a road surface inclination state detection method and a vehicle control method.

Background Art

[0002] In recent years, in vehicles such as automobiles, a configuration for controlling vehicle-mounted components has been proposed in order to stabilize the posture of the vehicle during driving.

[0003] Under such circumstances, Patent Document 1 relates to a vehicle attitude correction control device, and particularly in a two-wheeled vehicle, when the vehicle has a tendency to roll backward during a vehicle jump, by performing backward rotation control as vehicle attitude correction control, a force is applied in a direction in which the front side of the vehicle goes down, so that the tendency to roll backward is suppressed, and when the vehicle has a tendency to roll forward during a vehicle jump, by performing forward rotation control as vehicle attitude correction control, a force is applied in a direction in which the front side of the vehicle goes up, so that the tendency to roll forward is suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, according to the study of the present inventor, in the configuration of Patent Document 1, although it is intended to improve the stability of the vehicle during a vehicle jump, when the vehicle is jumping and the pitch angle of the vehicle is large, by adjusting the braking force and driving force of the rear wheels to increase or decrease the rotational speed of the rear wheels, or by adjusting the braking force of the front wheels to decrease the rotational speed of the front wheels, it discloses correcting the pitch attitude of the vehicle.

[0006] Further investigation by the inventors has revealed that while this configuration takes into account the vehicle's own jump and pitch angle when correcting its posture, it does not take into account the inclination of the road surface on which the vehicle is traveling. Therefore, there is room for improvement in this respect. Furthermore, further investigation by the inventors has revealed that the braking and driving forces of the rear wheels, as well as the braking force of the front wheels, are originally adjusted by the driver's own will and operation. Therefore, if the vehicle suddenly intervenes in these matters when a change in the vehicle's posture occurs, the driver tends to feel uncomfortable. Therefore, there is room for improvement in this respect.

[0007] The present invention was made after the above considerations, and aims to provide a road surface inclination detection method that can appropriately detect the inclination state of the road surface on which a vehicle is traveling, and further, a vehicle control method that can appropriately detect the inclination state of the road surface on which a vehicle is traveling, and can appropriately control the attitude of the vehicle in a manner that reduces the discomfort experienced by the driver. [Means for solving the problem]

[0008] To achieve the above objectives, in one aspect of the present invention, a road surface inclination state detection method comprises: an acquisition step of acquiring a vehicle state in which a pitching moment is applied to the vehicle such that the front wheels of the vehicle move vertically upward relative to the rear wheels of the vehicle, and the rear suspension that suspends the rear wheels is in a compression stroke; a counting step of starting counting after the vehicle state acquired in the acquisition step satisfies predetermined conditions and continuing the counting until the vehicle state no longer satisfies the predetermined conditions; and an inclination state detection step of detecting the inclination state of the road surface on which the vehicle is traveling according to the count value counted in the counting step.

[0009] Furthermore, in another aspect of the present invention, the vehicle control method comprises: a calculation step of calculating the pitch speed of the vehicle, the pitch angle of the vehicle, and the vertical velocity of the vehicle's sprung mass; a count step of starting counting after the pitch speed, pitch angle, and vertical velocity calculated in the calculation step all exceed predetermined thresholds set accordingly; a ramp size calculation step of calculating the ramp size when the road surface on which the vehicle travels is a ramp surface, according to the count values ​​calculated in the count step; and a control step of controlling the damping force of at least one of the vehicle's front suspension and rear suspension according to the ramp size calculated in the ramp size calculation step.

[0010] Furthermore, in yet another aspect of the present invention, the vehicle control method comprises: a calculation step of calculating the pitch speed of the vehicle, the pitch angle of the vehicle, and the vertical velocity of the vehicle's sprung mass, and applying a high-pass filter to reduce the offset and drift components in the pitch speed, pitch angle, and vertical velocity during these calculations; a count step of starting counting after the pitch speed, pitch angle, and vertical velocity calculated in the calculation step while applying the high-pass filter have all exceeded predetermined thresholds set accordingly; a tilt state detection step of detecting the tilt state of the road surface on which the vehicle is traveling according to the count values ​​counted in the count step; and a control step of controlling the damping force of at least one of the vehicle's front suspension and rear suspension according to the tilt state detected in the tilt state detection step. [Effects of the Invention]

[0011] According to a road surface inclination state detection method according to one aspect of the present invention, the method includes: an acquisition step to acquire a vehicle state in which a pitching moment is applied to the vehicle such that the front wheels of the vehicle move vertically upward relative to the rear wheels of the vehicle, and the rear suspension that suspends the rear wheels is in a compression stroke; a counting step which starts counting after the vehicle state acquired in the acquisition step satisfies predetermined conditions and continues counting until the vehicle state no longer satisfies the predetermined conditions; and an inclination state detection step which detects the inclination state of the road surface on which the vehicle is traveling according to the count value calculated in the counting step. By including these steps, the inclination state of the road surface on which the vehicle is traveling can be appropriately detected.

[0012] Furthermore, according to another aspect of the present invention, the vehicle control method includes a calculation step for calculating the pitch speed of the vehicle, the pitch angle of the vehicle, and the vertical velocity of the vehicle's sprung mass; a count step for starting counting after the pitch speed, pitch angle, and vertical velocity calculated in the calculation step all exceed predetermined thresholds set accordingly; a ramp size calculation step for calculating the ramp size when the road surface is a ramp surface according to the count values ​​calculated in the count step; and a control step for controlling the damping force of at least one of the vehicle's front suspension and rear suspension according to the ramp size calculated in the ramp size calculation step. As such, the inclination state of the road surface on which the vehicle is traveling can be appropriately detected, and the vehicle's attitude can be appropriately controlled in a manner that reduces discomfort experienced by the driver.

[0013] Furthermore, according to yet another aspect of the present invention, the vehicle control method includes: a calculation step in which the pitch speed of the vehicle, the pitch angle of the vehicle, and the vertical speed of the vehicle's sprung mass are calculated, and a high-pass filter is applied to reduce the offset and drift components in the pitch speed, pitch angle, and vertical speed during these calculations; a counting step in which counting begins only after the pitch speed, pitch angle, and vertical speed calculated in the calculation step while applying the high-pass filter have all exceeded predetermined thresholds set accordingly; a tilt state detection step in which the tilt state of the road surface is detected according to the count values ​​counted in the counting step; and a control step in which the damping force of at least one of the vehicle's front suspension and rear suspension is controlled according to the tilt state detected in the tilt state detection step. As a result, the tilt state of the road surface on which the vehicle is traveling can be appropriately detected, and the vehicle's attitude can be appropriately controlled in a manner that reduces discomfort experienced by the driver. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a side view showing the right side of a vehicle on which the vehicle control system and device according to an embodiment of the present invention are mounted. [Figure 2] Figure 2 is a schematic diagram showing the configuration of the vehicle control system and device in this embodiment. [Figure 3] Figure 3 is a side view showing the right side of a vehicle in an inclined state, on which the vehicle control system and device according to this embodiment are mounted. [Figure 4] Figure 4 is a time chart showing an example of the operation of the vehicle control system and device in this embodiment. [Figure 5] Figure 5 is a flowchart showing an example of the road surface inclination state detection process performed by the vehicle control system and device in this embodiment. [Figure 6] Figure 6 is a flowchart showing an example of a vehicle control process performed by the vehicle control system and device in this embodiment. [Figure 7]FIG. 7 is a flowchart showing another example of the vehicle control process executed by the vehicle control system and apparatus in the present embodiment. [Figure 8] FIG. 8 is a flowchart showing yet another example of the vehicle control process executed by the vehicle control system and apparatus in the present embodiment.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, referring to the drawings as appropriate, the vehicle control system, apparatus, and method in the embodiments of the present invention will be described in detail. In the figures, the x-axis, y-axis, and z-axis form a three-axis orthogonal coordinate system. The direction of the x-axis is the longitudinal direction and the traveling direction of the vehicle, and its forward direction is shown as the positive direction of the x-axis. The direction of the y-axis is the width direction of the vehicle, and its left direction is shown as the direction penetrating the paper surface from the front side to the back side in FIGS. 1 and 3. The direction of the z-axis is the vertical direction and the vertical direction of the vehicle, and its upward direction is shown as the positive direction of the z-axis. Also, the horizontal plane is assumed to be parallel to the plane defined by the x-axis and the y-axis.

[0016] 〔Configuration Regarding Vehicle〕 First, referring to FIG. 1, the configuration of the vehicle to which the left direction as the width direction of the vehicle in the present embodiment is applied as the positive direction of the y-axis will be described in detail.

[0017] FIG. 1 is a side view showing the right side of the vehicle on which the vehicle control system and apparatus in the present embodiment are mounted. In the figure, only the front suspension, front wheels, rear suspension, and rear wheels arranged on the right side are shown, but typically, these are a pair on the left and right and are similarly arranged on the left side.

[0018] As shown in Figure 1 as a typical example of a small, lightweight four-wheeled off-road vehicle, a side-by-side vehicle, the vehicle 1 typically comprises a body 10 made of metal frame members such as steel pipes or steel plates (not shown), a drive source 20 that outputs the driving force of the vehicle 1, a front suspension 30 interposed between the body 10 and the front wheels 32 to suspend the front wheels 32, and a rear suspension 40 interposed between the body 10 and the rear wheels 42 to suspend the rear wheels 42. In addition to being called a side-by-side vehicle, the vehicle 1 may also be called a UTV (Utility Task Vehicle) or ROV (Recreational Off-highway Vehicle), and may be a three-wheeled vehicle in addition to a four-wheeled vehicle. The drive source 20 can be an internal combustion engine, an electric motor, or a combination of an engine and an electric motor. Furthermore, in vehicle 1, the drive wheels may be either the front wheels 32 or the rear wheels 42, or both, and the steering wheels may be either the front wheels 32 only or both the front wheels 32 and the rear wheels 42. The road surface on which vehicle 1 travels is indicated by the symbol R.

[0019] The front suspension 30 is electronically controlled and typically has an oil-type front damper 34 and a front spring 36 such as a coil spring made of metal. By operating an actuator (not shown), the damping force can be variably adjusted by increasing or decreasing the orifice diameter of the front damper 34, etc. Further, if necessary, in addition to this, by increasing or decreasing the oil supply amount, etc., the stroke position in the bump direction or the rebound direction is changed, and at the front part of the vehicle 1, the vehicle height, which is the height of the vehicle body 10 from the road surface, can be variably adjusted. Similarly, the rear suspension 40 is electronically controlled and typically has an oil-type rear damper 44 and a rear spring 46 such as a coil spring made of metal. The damping force of the rear damper 44 can be variably adjusted, and further, if necessary, in addition to this, at the rear part of the vehicle 1, the vehicle height can be variably adjusted. In the figure, the front suspension 30 and the rear suspension 40 are shown in a strut type, but they may be of other types having a configuration such as arranging the damper and the spring on separate axes.

[0020] Furthermore, the vehicle 1 is equipped with a drive source control device 60, which controls the operating state of the drive source 20, mounted on the vehicle body 10 or a support member connected thereto. The drive source control device 60 is mounted on the vehicle 1 and operates using a battery (not shown) as its power source, and is mainly composed of an ECU (Electronic Control Unit), which is a processing unit including a microcomputer consisting of a CPU (Central Processing Unit), etc. For example, when an engine is used as the drive source 20, the drive source (engine) control device 60 controls the operating state of the ignition system, fuel supply system, and intake system components such as spark plugs, injectors, and throttle valves (not shown), thereby controlling the operating state of the drive source (engine) 20. When an electric motor is used as the drive source 20, the drive source (motor) control device 60 controls the operating state of the drive source (motor) 20 by controlling the on / off operation of the switching elements of an inverter (not shown). The control program and control data used by the drive source control device 60 are pre-stored in a memory (not shown in the diagram) and are read from that memory when they are executed.

[0021] [Configuration and operation of vehicle control systems and devices] Next, with further reference to Figures 2 to 8, the configuration and operation of the vehicle control system and device in this embodiment will be described in detail.

[0022] Figure 2 is a schematic diagram showing the configuration of the vehicle control system and device in this embodiment. Figure 3 is a side view showing the right side of a vehicle in an inclined state with the vehicle control system and device in this embodiment mounted on it. Figure 4 is a time chart showing an example of the operation of the vehicle control system and device in this embodiment. Figure 5 is a flowchart showing an example of the road surface inclination state detection process performed by the vehicle control system and device in this embodiment. Figure 6 is a flowchart showing an example of the vehicle control process performed by the vehicle control system and device in this embodiment. Figure 7 is a flowchart showing another example of the vehicle control process performed by the vehicle control system and device in this embodiment. Figure 8 is a flowchart showing yet another example of the vehicle control process performed by the vehicle control system and device in this embodiment.

[0023] As shown in Figures 1 and 2, the vehicle control system S includes a vehicle control device 100, and in addition thereto various sensors 200 including an IMU (Inertial Measurement Unit) 202, a stroke sensor 204, a vehicle speed sensor 206, and an acceleration sensor 208, as well as a front suspension 30 and a rear suspension 40.

[0024] The vehicle control device 100 is mounted on the vehicle 1 and operates using a battery (not shown) as its power source. It is primarily composed of an ECU, which is a processing unit including a microcomputer consisting of a CPU 160 and the like. Various sensors 200, including an IMU 202, a stroke sensor 204, a vehicle speed sensor 206, and an acceleration sensor 208, are electrically connected to the vehicle control device 100. The vehicle control device 100 functions as a control device that variably controls the damping force and stroke position of the front suspension 30 and the rear suspension 40 by executing a control program based on electrical signals output from these sensors and the like, while referring to control data. These are shown as functional blocks and include the first to fourth input units 152 to 158, as well as the acquisition unit 162, counting unit 164, tilt state detection unit 166, and control unit 168 within the CPU 160. The control program and the like are pre-stored in a memory (not shown) and read from that memory when it is executed. The vehicle control device 100 may be an integrated control device with the drive source control device 60. In this case, the vehicle control device 100 functions as a control device that controls the operating state of the engine, which is the drive source 20, and also functions as a control device that variably controls the damping force and stroke position of the front suspension 30 and the rear suspension 40, respectively. The vehicle control device 100 may also be an integrated control device with a dashboard display control device or a vehicle body control device.

[0025] The first input unit 152 is an electrical circuit that receives an output from the IMU 202, which detects acceleration in three axial directions parallel to the x, y, and z axes of the vehicle, as well as angular acceleration around these three axes, and also receives electrical signals indicating such acceleration and angular acceleration. The IMU 202 has an acceleration sensor (G sensor) and a gyro sensor, both of which are not shown in the diagram. The acceleration sensor detects acceleration in three axial directions parallel to the x, y, and z axes, and the gyro sensor detects angular velocity around these three axes parallel to the x, y, and z axes.

[0026] The second input unit 154 is an electrical circuit that receives an output from a stroke sensor 204 that detects the amount of stroke within the effective stroke length range between full bump and full rebound of the left and right front suspensions 30 and rear suspensions 40, respectively, based on the 1G position, and also receives an electrical signal indicating such a stroke amount.

[0027] The third input unit 156 is an electrical circuit that receives an output from a vehicle speed sensor 206, which detects the rotational speed of the output shaft of the transmission (vehicle 1 is not shown in the illustration), and also receives an electrical signal indicating that rotational speed. If necessary, the vehicle speed sensor 206 may detect the rotational speed of a wheel such as the front wheel 32 instead of the rotational speed of the output shaft of the transmission.

[0028] The fourth input unit 158 ​​is an electrical circuit that receives an output from an acceleration sensor (G sensor) 208 that detects acceleration in the x, y, and z axes, as well as an electrical signal indicating such acceleration. The acceleration sensor 208 may typically be replaced by an IMU 202.

[0029] The acquisition unit 162 acquires a vehicle state (vehicle attitude state) in which a pitching moment is applied to the vehicle 1, causing the front wheels 32 to move upward relative to the rear wheels 42, and the rear suspension 40 is in a compression stroke, based on an electrical signal output from the IMU 202 and input to the first input unit 152. Specifically, it is preferable for the acquisition unit 162 to acquire the pitch speed, pitch angle, and vertical speed of the vehicle 1 in order to appropriately acquire such vehicle attitude state. Here, the pitch speed of the vehicle 1 is the angular velocity A of the vehicle 1 around the pitch axis, which can be acquired by the acquisition unit 162 based on the output signal output from the gyro sensor of the IMU 202. This pitch axis is typically an axis that extends parallel to the width direction (y-axis direction) through the center of gravity of the vehicle 1. Furthermore, the pitch angle of vehicle 1 can be calculated by the acquisition unit 162 based on the output signal from the acceleration sensor of IMU 202, and is the inclination angle θ of vehicle 1 with respect to the horizontal plane, which typically corresponds to the inclination angle θ of the road surface R with respect to the horizontal plane. Also, the vertical velocity of vehicle 1 can be calculated by the acquisition unit 162 based on the output signal from the acceleration sensor of IMU 202, and is the velocity V of vehicle 1 moving parallel to the z-axis.

[0030] Furthermore, the acquisition unit 162 may calculate the pitch speed A, pitch angle θ, and vertical speed V of the vehicle 1 based on the electrical signals output from the stroke sensor 204 and input to the second input unit 154, in order to appropriately acquire the vehicle attitude state in which a pitching moment is applied to the vehicle 1 in which the front wheels 32 move relatively upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction. In such a case, for example, the pitch speed of vehicle 1 can be calculated by the acquisition unit 162 differentiating the pitch angle of vehicle 1 calculated by the acquisition unit 162 based on the output signals output from left and right front and rear stroke sensors 204 provided in correspondence with the left and right front suspensions 30 and rear suspension 40. The pitch angle of vehicle 1 can be calculated by the acquisition unit 162 using the difference in front and rear stroke amounts based on the output signals output from the left and right front and rear stroke sensors 204. The vertical speed of vehicle 1 can be calculated by the acquisition unit 162 differentiating the vertical component of each front and rear stroke amount based on the output signals output from the front and rear stroke sensors 204.

[0031] Furthermore, the acquisition unit 162 may calculate the pitch speed A, pitch angle θ, and vertical velocity V of the vehicle 1 based on the electrical signals output from the acceleration sensor 208 and input to the fourth input unit 158, in order to appropriately acquire the vehicle attitude state in which a pitching moment is applied to the vehicle 1 in which the front wheels 32 move relatively upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction. In such a case, for example, the pitch speed of the vehicle 1 can be calculated by the acquisition unit 162 by differentiating the pitch angle of the vehicle 1 calculated by the acquisition unit 162 based on the output signal output from the acceleration sensor 208, the pitch angle of the vehicle 1 can be calculated by the acquisition unit 162 based on the output signal output from the acceleration sensor 208 in accordance with the component ratio of acceleration, etc., and the vertical velocity of the so-called sprung mass of the vehicle 1 can be calculated by the acquisition unit 162 by integrating the vertical acceleration based on the output signal output from the acceleration sensor 208.

[0032] Furthermore, when the acquisition unit 162 acquires the pitch speed A, pitch angle θ, and vertical speed V of the vehicle 1, it may apply a high-pass filter to the electrical signals input to the first input unit 152, the second input unit 154, and the fourth input unit 158. This makes it possible to reduce the error components and drift and offset components caused by gravitational acceleration components that accumulate during such calculations.

[0033] The counting unit 164 starts counting after the vehicle posture state acquired by the acquisition unit 162 satisfies predetermined conditions, so as to be able to appropriately detect the inclination state of the road surface R such that a vehicle posture state occurs in which a pitching moment is applied to the vehicle 1 in which the front wheels 32 move relatively upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction, and continues counting until such a vehicle posture state no longer satisfies the predetermined conditions. Specifically, it is preferable that the counting unit 164 starts counting after the pitch speed A, pitch angle θ, and vertical speed V of the vehicle 1 acquired by the acquisition unit 162 all exceed predetermined thresholds set for each of them, so as to be able to more appropriately detect the inclination state of the road surface R, in other words, when the road surface R, which was a flat road surface, changes to a ramp road surface which is an inclined road surface. Furthermore, in order to more appropriately detect when the road surface R changes to a ramp surface, it is preferable that the predetermined thresholds for the pitch speed A and pitch angle θ of the vehicle 1 be set to positive values, with the rotational direction in which the front wheels 32 move relatively upward relative to the rear wheels 42 being considered positive, and the vertical speed V be set to positive values ​​with the positive direction of the z axis being considered positive. In addition, the counting unit 164 should continue counting as long as the pitch speed A, pitch angle θ, and vertical speed V exceed their respective predetermined thresholds, in order to more appropriately detect when the road surface R is a ramp surface, and clear the counted values ​​when they fall below these predetermined thresholds. Note that, in order to prevent counting from taking an unnecessarily long time, the counting unit 164 may saturate the counted values ​​to fix them after a predetermined time has elapsed since counting began after all of the predetermined thresholds have been exceeded.

[0034] Here, as shown in Figure 4, the period during which the pitch velocity A exceeds the pitch velocity threshold set to a positive value is between time t3 and time t5, and between time t8 and time t11 (during these periods, the corresponding flag changes from a low level L to a high level H and is maintained at a high level H), the period during which the pitch angle θ exceeds the pitch angle threshold set to a positive value is until time t1, between time t2 and time t7, and from time t10 onwards (during these periods, the corresponding flag changes from a low level L to a high level H and is maintained at a high level H), and the period during which the vertical velocity V exceeds the vertical velocity threshold set to a positive value is between time t4 and time t6, and between time t9 and time t12 (during these periods, the corresponding flag changes from a low level L to a high level H and is maintained at a high level H). As a result, the period during which pitch velocity A exceeds the pitch velocity threshold, pitch angle θ exceeds the pitch angle threshold, and vertical velocity V exceeds the vertical velocity threshold is between time t4 and time t5, and between time t10 and time t11 (during these periods, the corresponding threshold flag changes from low level L to high level H and is maintained at high level H).

[0035] The tilt state detection unit 166 detects, according to the count values ​​counted by the count unit 164, a tilt state in which the road surface R on which the vehicle 1 is traveling exhibits a vehicle posture where a pitching moment is applied to the vehicle 1 such that the front wheels 32 move upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction; in other words, the tilt state of the road surface R when it changes from a flat road to a ramp road. Specifically, it is preferable for the tilt state detection unit 166 to calculate the size of the ramp road on the road surface R (ramp size) according to the count values ​​counted by the count unit 164 in order to more appropriately detect the tilt state of the road surface R, that is, the tilt state of the road surface R when it is a ramp road. Furthermore, if it is assumed that the vehicle 1 has finished passing over the road surface R which is a ramp road, the tilt state detection unit 166 may terminate the detection of the tilt state of the road surface R when the stroke of the rear suspension 40 reaches its maximum extension, so as not to prolong the detection of the tilt state unnecessarily. Furthermore, the inclination state detection unit 166 may detect the inclination state of the road surface R when the speed of the vehicle 1 (vehicle speed), calculated based on the electrical signal input to the third input unit 156, is equal to or greater than a predetermined threshold, in order to appropriately detect the inclination state of the road surface R while the vehicle 1 is in motion. The ramp size, which is the size of the ramp road surface, is typically defined by the length in the direction of travel of the vehicle 1 and the vertical length (height).

[0036] The control unit 168 controls the components of the vehicle 1 in accordance with the inclination state of the road surface R detected by the inclination state detection unit 166, in order to control the vehicle 1's posture in a manner that reduces the discomfort felt by the driver when the vehicle 1 experiences a change in posture due to the influence of an inclined road surface R. The components of the vehicle 1 are preferably at least one of the front suspension 30 and the rear suspension 40, and in this case, the control unit 168 controls the damping force of at least one of these. Specifically, the control unit 168 controls the damping force of at least one of the front suspension 30 and the rear suspension 40 in accordance with the ramp size detected by the inclination state detection unit 166, and typically, it is preferable to increase the damping force of at least one of the front suspension 30 and the rear suspension 40 as the ramp size detected by the inclination state detection unit 166 increases. Furthermore, for example, if the rear suspension 40 attempts to stroke in the extension direction as a reaction to the rear suspension 40 stroking in the compression direction, the control unit 168 may adjust the damping force of the rear suspension 40 to suppress this, and may also adjust the damping force of the front suspension 30 to suppress changes in the vehicle 1's posture as needed. When adjusting the damping force of at least one of the front suspension 30 and the rear suspension 40, the values ​​of the length in the direction of travel and the vertical length (height) of the vehicle 1 that define the ramp size may be used as parameters, and the values ​​of each damping force may be set according to the values ​​of these parameters. In addition, if necessary, the stroke position of at least one of the front suspension 30 and the rear suspension 40 may be adjusted in addition to the damping force of at least one of the front suspension 30 and the rear suspension 40.

[0037] An example of an operation performed by the vehicle control device 100 having the above configuration will be described in detail below with reference to Figures 5 to 8.

[0038] First, focusing on the operation of the acquisition unit 162, counting unit 164, and tilt state detection unit 166 in the vehicle control device 100, one example of such operation is the road surface tilt state detection process shown in the flowchart in Figure 5. The road surface tilt state detection process shown in Figure 5 typically starts when the power switch (vehicle not shown) is switched from the off state to the on state and the CPU 110 of the vehicle control device 100 becomes operational, and the road surface tilt state detection process proceeds to step S1. This road surface tilt state detection process is executed repeatedly at predetermined intervals within the period in which the CPU 110 is operational.

[0039] As shown in Figure 5, in step S1, the acquisition unit 162 acquires the vehicle attitude state in which a pitching moment is applied to the vehicle 1, causing the front wheels 32 to move upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction, based on the electrical signal output from the IMU 202 and input to the first input unit 152, as described above. Specifically, it is preferable to acquire the pitch speed, pitch angle, and vertical speed of the vehicle 1 in order to acquire such vehicle attitude state more appropriately. The acquisition unit 162 may also calculate the pitch speed A, pitch angle θ, and vertical speed V of the vehicle 1 based on the electrical signal output from the stroke sensor 204 and input to the second input unit 154, as described above, or it may calculate the pitch speed A, pitch angle θ, and vertical speed V of the vehicle 1 based on the electrical signal output from the acceleration sensor 208 and input to the fourth input unit 158. Furthermore, as described above, when the acquisition unit 162 calculates the pitch speed A, pitch angle θ, and vertical speed V of the vehicle 1, it may apply a high-pass filter to the electrical signals input to the first input unit 152, the second input unit 154, and the fourth input unit 158. With this, the processing of step S1 is completed, and the road surface inclination state detection process proceeds to the processing of step S2.

[0040] In the process of step S2, the counting unit 164 starts counting after the vehicle posture state acquired by the acquisition unit 162 satisfies predetermined conditions, so as described above, it is possible to appropriately detect the inclination state of the road surface R such that a vehicle posture state occurs in which a pitching moment is applied to the vehicle 1 in which the front wheels 32 move relatively upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction. The counting unit 164 continues counting until such a vehicle posture state no longer satisfies predetermined conditions. Specifically, it is preferable to start counting after the pitch speed A, pitch angle θ, and vertical speed V of the vehicle 1 acquired by the acquisition unit 162 all exceed predetermined thresholds set corresponding to each, so as to be able to more appropriately detect the inclination state of the road surface R, in other words, when the road surface R, which was a flat road surface, changes to a ramp road surface which is an inclined road surface. Furthermore, as mentioned above, in order to more appropriately detect when the road surface R changes to a ramp surface, it is preferable that the predetermined thresholds for the pitch speed A and pitch angle θ of the vehicle 1 be set to zero or a positive value, with the rotational direction in which the front wheels 32 move relatively upward relative to the rear wheels 42 being considered positive, and the vertical speed V be set to a positive value in the positive direction of the z axis. Also, as mentioned above, the counting unit 164 should continue counting as long as the pitch speed A, pitch angle θ, and vertical speed V exceed their respective predetermined thresholds, in order to more appropriately detect when the road surface R is a ramp surface, and clear the counted value when it falls below the predetermined threshold. In addition, as mentioned above, in order to prevent counting from taking an unnecessarily long time, the counting unit 164 may saturate the counted value to fix it after a predetermined time has elapsed since counting started after each predetermined threshold was exceeded. With this, the processing of step S2 is completed, and the road surface inclination state detection processing proceeds to the processing of step S3.

[0041] In step S3, the tilt state detection unit 166 detects, as described above, the tilt state of the road surface R on which the vehicle 1 is traveling, in accordance with the count values ​​counted by the count unit 164, such that a pitching moment is applied to the vehicle 1, causing the front wheels 32 to move upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction. In other words, it detects the tilt state of the road surface R as it changes from a flat road to a ramp road. Specifically, it is preferable for the tilt state detection unit 166 to calculate the ramp size on the road surface R in accordance with the count values ​​counted by the count unit 164 so as to be able to more appropriately detect the tilt state of the road surface R, that is, the tilt state of the road surface R which is a ramp road. Furthermore, if it is assumed that the vehicle 1 has finished passing over the road surface R which is a ramp road, the tilt state detection unit 166 may terminate the detection of the tilt state of the road surface R when the stroke of the rear suspension 40 reaches its maximum extension, so as not to prolong the detection of the tilt state unnecessarily. Furthermore, the inclination state detection unit 166 may detect the inclination state of the road surface R while the vehicle 1 is in motion, when the vehicle speed calculated based on the electrical signal input to the third input unit 156 is equal to or greater than a predetermined threshold. This completes the series of road surface inclination state detection processes described above.

[0042] Next, focusing on the operation of the control unit 168 in addition to the acquisition unit 162, counting unit 164, and tilt state detection unit 166 in the vehicle control device 100, one example of such operation is the vehicle control process shown in the flowchart in Figure 6. In this vehicle control process, the processes from step S1 to step S3 are the same as the road surface tilt state detection process shown in Figure 5, and once the process of step S3 is completed, the vehicle control process proceeds to the process of step S4.

[0043] As shown in Figure 6, in step S4, the control unit 168 controls the damping force of at least one of the components of the vehicle 1, typically the front suspension 30 and the rear suspension 40, according to the inclination of the road surface R detected by the inclination state detection unit 166, in order to control the vehicle 1's posture in a manner that reduces the discomfort felt by the driver when a change in posture occurs in the vehicle 1 due to the influence of the inclined road surface R, as described above. Specifically, the control unit controls the damping force of at least one of the front suspension 30 and the rear suspension 40 according to the ramp size detected by the inclination state detection unit 166. Furthermore, when adjusting the damping force of at least one of the front suspension 30 and the rear suspension 40, the values ​​of the length in the direction of travel and the vertical length (height) of the vehicle 1 that define the ramp size may be used as parameters, and the value of each damping force may be set according to the values ​​of these parameters. When setting the damping force value in this way, the control unit 168 may read and refer to table data stored in memory that has been predetermined to define the relationship between the values ​​of such parameters and the damping force value. With this, the series of vehicle control processes is completed.

[0044] Next, regarding the operation of the acquisition unit 162, counting unit 164, tilt state detection unit 166, and control unit 168 in the vehicle control device 100, we focus on the fact that the acquisition unit 162 acquires the pitch speed, pitch angle, and vertical speed of the vehicle 1 based on the electrical signal output from the IMU 202 and input to the first input unit 152, the electrical signal output from the stroke sensor 204 and input to the second input unit 154, or the electrical signal output from the acceleration sensor 208 and input to the fourth input unit 158, as described above. We also focus on the fact that the tilt state detection unit 166 calculates the ramp size on the road surface R according to the count value counted by the counting unit 164, as described above. As an example of such operation, a vehicle control process like the flowchart shown in Figure 7 can be cited. In this vehicle control process, steps S2 and S4 are the same as the vehicle control process shown in Figure 6, and steps S1 and S3 are replaced by steps S11 and S13.

[0045] As shown in Figure 7, in step S11, the acquisition unit 162 acquires the pitch speed, pitch angle, and vertical speed of the vehicle 1 based on the electrical signal output from the IMU 202 and input to the first input unit 152, the electrical signal output from the stroke sensor 204 and input to the second input unit 154, or the electrical signal output from the acceleration sensor 208 and input to the fourth input unit 158, in order to more appropriately acquire the vehicle attitude state in which a pitching moment is applied to the vehicle 1 such that the front wheels 32 move relatively upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction. With this, the processing of step S11 is completed, and the vehicle control processing proceeds to step S2. After the processing of step S2 is completed, the vehicle control processing proceeds to step S13.

[0046] In step S13, the tilt state detection unit 166 calculates the ramp size on the road surface R according to the count values ​​counted by the count unit 164, in order to more appropriately detect the tilt state on the road surface R on which the vehicle 1 is traveling, such that a pitching moment is applied to the vehicle 1, causing the front wheels 32 to move upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction. In other words, it calculates the ramp size on the road surface R according to the count values ​​counted by the count unit 164, in order to more appropriately detect the tilt state of the road surface R on which the vehicle 1 is traveling, where the road surface R changes from a flat road to a ramp road surface. With this, the process of step S13 is completed, and the vehicle control process proceeds to the process of step S4. Once the process of step S4 is completed, this series of vehicle control processes is finished.

[0047] Next, regarding the operation of the acquisition unit 162, counting unit 164, tilt state detection unit 166, and control unit 168 in the vehicle control device 100, the contents performed by the acquisition unit 162 are, as described above, to acquire the pitch speed, pitch angle, and vertical speed of the vehicle 1 based on the electrical signal output from the IMU 202 and input to the first input unit 152, the electrical signal output from the stroke sensor 204 and input to the second input unit 154, or the electrical signal output from the acceleration sensor 208 and input to the fourth input unit 158. Furthermore, when the acquisition unit 162 acquires the pitch speed A, pitch angle θ, and vertical speed V of the vehicle 1, as described above, it applies a high-pass filter to the electrical signals input to the first input unit 152, the second input unit 154, and the fourth input unit 158. As an example of such operation, a vehicle control process like the flowchart shown in Figure 8 can be cited. In this vehicle control process, the processes from step S2 to step S4 are the same as the vehicle control process shown in Figure 6, and the process of step S1 is replaced by the process of step S21.

[0048] As shown in Figure 8, in step S21, the acquisition unit 162 acquires the pitch speed, pitch angle, and vertical speed of the vehicle 1 based on the electrical signal output from the IMU 202 and input to the first input unit 152, the electrical signal output from the stroke sensor 204 and input to the second input unit 154, or the electrical signal output from the acceleration sensor 208 and input to the fourth input unit 158, in order to more appropriately acquire the vehicle attitude state in which a pitching moment is applied to the vehicle 1 such that the front wheels 32 move relatively upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction. Here, as described above, the acquisition unit 162 applies high-pass filtering to the electrical signals input to the first input unit 152, the second input unit 154, and the fourth input unit 158, and acquires the pitch speed A, pitch angle θ, and vertical speed V of the vehicle 1 based on each of the high-pass filtered electrical signals, and reduces drift and offset components caused by error components and gravitational acceleration components accumulated during such acquisition. As a result, the process in step S21 is completed, and the vehicle control process proceeds sequentially to steps S2, S3, and S4. Once the process in step S4 is completed, this series of vehicle control processes is terminated.

[0049] As is clear from the above description, in the first phase of the road surface inclination state detection method in this embodiment, the method includes an acquisition step to acquire a vehicle state in which a pitching moment is applied to the vehicle 1 such that the front wheels 32 of the vehicle 1 move vertically upward relative to the rear wheels 42 of the vehicle 1, and the rear suspension 40 that suspends the rear wheels 42 is in a compression stroke; a counting step which starts counting after the vehicle state acquired in the acquisition step satisfies predetermined conditions and continues counting until the vehicle state no longer satisfies the predetermined conditions; and an inclination state detection step which detects the inclination state of the road surface R on which the vehicle 1 is traveling according to the count value calculated in the counting step. By providing this method, the inclination state of the road surface R on which the vehicle 1 is traveling can be appropriately detected.

[0050] Furthermore, in the second aspect of the road surface inclination state detection method in this embodiment, in addition to the first aspect, the acquisition step acquires the pitch speed of vehicle 1, the pitch angle of vehicle 1, and the vertical velocity of the sprung mass of vehicle 1 in order to acquire the vehicle state, and the counting step starts counting after all of the pitch speed, pitch angle, and vertical velocity acquired in the acquisition step have exceeded predetermined thresholds set for each of them, thereby enabling more appropriate detection that the road surface R, which was a flat road surface, has changed to a ramp road surface which is an inclined road surface.

[0051] Furthermore, in the third phase of the road surface inclination state detection method in this embodiment, in addition to the second phase, predetermined thresholds set in accordance with the pitch speed, pitch angle, and vertical speed are each set to zero or a positive value, thereby enabling more appropriate detection of the change from a flat road surface R to an inclined road surface, which is a ramp road surface.

[0052] Furthermore, in the fourth aspect of the road surface inclination state detection method in this embodiment, in addition to the third aspect, the count step clears the count value when any of the pitch speed, pitch angle, or vertical speed acquired in the acquisition step falls below a predetermined threshold, thereby enabling more appropriate detection of the road surface R being a ramp road surface.

[0053] Furthermore, in the fifth phase of the road surface inclination state detection method in this embodiment, in addition to any of the first to fourth phases, the count step can suppress the counting from continuing for an unnecessarily long period of time by saturating the count value after a predetermined time has elapsed since the start of counting.

[0054] Furthermore, in the sixth phase of the road surface inclination state detection method in this embodiment, in addition to any of the first to fifth phases, the inclination state detection step calculates the ramp size of the ramp road surface according to the count value counted by the count step, and the control step controls the vehicle to increase the damping force of at least one of the vehicle's front suspension 30 and rear suspension 40 as the ramp size increases. This allows for more appropriate detection of the inclination state of the road surface R, which is the ramp road surface, and enables control of the vehicle's posture in a manner that reduces discomfort experienced by the driver.

[0055] Furthermore, in the seventh aspect of the road surface inclination state detection method in this embodiment, in addition to any of the first to sixth aspects, the inclination state detection step terminates the detection of the inclination state when the stroke of the rear suspension 40 reaches its maximum extension, thereby preventing the detection of the inclination state from continuing for an unnecessarily long period of time.

[0056] Furthermore, in the eighth phase of the road surface inclination state detection method in this embodiment, in addition to the second phase, the acquisition step acquires the pitch speed, pitch angle, and vertical speed based on the electrical signal from the inertial measuring device 202, thereby appropriately calculating the vehicle attitude state in which a pitching moment is applied to the vehicle 1 such that the front wheels 32 move relatively upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction.

[0057] Furthermore, in the ninth phase of the road surface inclination state detection method in this embodiment, in addition to the second phase, the acquisition step calculates the pitch speed, pitch angle, and vertical speed based on the electrical signal from the stroke sensor 204, thereby appropriately calculating the vehicle posture state in which a pitching moment is applied to the vehicle 1 such that the front wheels 32 move relatively upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction.

[0058] Furthermore, in the tenth phase of the road surface inclination state detection method in this embodiment, in addition to the second phase, the acquisition step calculates the pitch speed, pitch angle, and vertical speed based on the electrical signal from the acceleration sensor 206, thereby appropriately calculating the vehicle posture state in which a pitching moment is applied to the vehicle 1 such that the front wheels 32 move relatively upward relative to the rear wheels 42, and the rear suspension 40 is stroking in the compression direction.

[0059] Furthermore, in the 11th aspect of the road surface inclination state detection method in this embodiment, in addition to any of the first to 10 aspects, the inclination state detection step detects the inclination state when the speed of the vehicle 1 is above a predetermined threshold, thereby enabling appropriate detection of the inclination state of the road surface R while the vehicle 1 is in motion.

[0060] Furthermore, in another aspect of the vehicle control method in this embodiment, the method includes an acquisition step to acquire the vehicle's pitch speed, pitch angle, and vertical velocity of the vehicle's sprung mass; a counting step to start counting after the pitch speed, pitch angle, and vertical velocity acquired in the acquisition step all exceed predetermined thresholds set accordingly; a ramp size calculation step to calculate the ramp size when the road surface is a ramp road surface according to the count values ​​calculated in the counting step; and a control step to control the damping force of at least one of the vehicle's front suspension and rear suspension according to the ramp size calculated in the ramp size calculation step. By providing this method, the inclination state of the road surface R, which is a ramp road surface, can be detected more appropriately, and the attitude of the vehicle 1 can be controlled in a manner that reduces the discomfort felt by the driver.

[0061] Furthermore, in yet another aspect of the vehicle control method in this embodiment, the method includes: a calculation step in which the pitch speed of the vehicle, the pitch angle of the vehicle, and the vertical velocity of the vehicle's sprung mass are calculated, and a high-pass filter is applied to reduce the offset and drift components in the pitch speed, pitch angle, and vertical velocity; a count step in which counting begins after the pitch speed, pitch angle, and vertical velocity calculated in the calculation step with the high-pass filter applied all exceed predetermined thresholds set for each of them; a tilt state detection step in which the tilt state of the road surface is detected according to the count values ​​counted in the count step; and a control step in which the damping force of at least one of the vehicle's front suspension and rear suspension is controlled according to the tilt state detected in the tilt state detection step. By reducing the drift and offset components caused by error components and gravitational acceleration components accumulated during the calculation step, the tilt state of the road surface R is detected more appropriately, reducing the detection of unnecessary tilt states, and the attitude of the vehicle 1 can be controlled in a manner that reduces the discomfort felt by the driver.

[0062] It should be noted that the present invention is not limited to the above-described embodiments in terms of the type, shape, arrangement, number, etc. of the components, and it is of course possible to modify them as appropriate without departing from the spirit of the invention, such as by appropriately substituting the components with those that produce equivalent effects. [Industrial applicability]

[0063] As described above, the present invention provides a road surface inclination detection method that can appropriately detect the inclination state of the road surface on which a vehicle is traveling, and further provides a vehicle control method that can appropriately detect the inclination state of the road surface on which a vehicle is traveling and control the vehicle's attitude in a manner that reduces discomfort experienced by the driver. Due to its general-purpose and universal nature, it is expected to be widely applicable to automobiles, including motorcycles. [Explanation of symbols]

[0064] S... Vehicle control system 1…Vehicle 10... Vehicle body 30…Front suspension 32…Front wheel 34…Front damper 36…Front springs 40... Rear suspension 42... Rear wheel 44... Rear damper 46... Rear spring 52...Brake pedal 54... Accelerator pedal 60…Drive source control device 100... Vehicle control device 152...First Input Section 154...Second input section 156...Third input section 158...4th input section 160...CPU 162…Acquisition Department 164... Count section 166... ​​Inclined road surface detection unit 168... Control Unit 202…IMU 204... Stroke sensor 206... Vehicle speed sensor 208...Accelerometer R…Road surface

Claims

1. An acquisition step to acquire a vehicle state in which a pitching moment is applied to the vehicle such that the front wheels of the vehicle move vertically upward relative to the rear wheels of the vehicle, and the rear suspension that suspends the rear wheels is in a compression stroke; A counting step in which the vehicle state acquired in the acquisition step starts counting after the predetermined conditions are met, and continues counting until the vehicle state no longer meets the predetermined conditions, A tilt state detection step detects the tilt state of the road surface on which the vehicle is traveling, in accordance with the count value obtained in the count step, A method for detecting road surface inclination, comprising the following features.

2. The acquisition step acquires the pitch speed of the vehicle, the pitch angle of the vehicle, and the vertical velocity of the vehicle's sprung mass in order to acquire the vehicle state. The road surface inclination state detection method according to claim 1, wherein the count step starts counting after the pitch speed, pitch angle, and vertical speed acquired in the acquisition step all exceed predetermined thresholds set corresponding to each of them.

3. The road surface inclination state detection method according to claim 2, wherein the predetermined thresholds are each set to zero or a positive value.

4. The road surface inclination state detection method according to claim 3, wherein the count step clears the count value when any of the pitch speed, pitch angle, and vertical speed acquired in the acquisition step falls below a predetermined threshold.

5. The road surface inclination state detection method according to any one of claims 1 to 4, wherein the count step saturates the count value after a predetermined time has elapsed since the start of the count.

6. The inclination state detection step calculates the ramp size of the ramp road surface, which is the road surface, according to the count value counted in the count step. Furthermore, the road surface inclination state detection method according to any one of claims 1 to 4 further comprises a control step of controlling the damping force of at least one of the front suspension and the rear suspension of the vehicle according to the size of the ramp.

7. The road surface inclination state detection method according to any one of claims 1 to 4, wherein the inclination state detection step terminates when the stroke of the rear suspension reaches its maximum extension.

8. The method for detecting road surface inclination state according to claim 2, wherein the acquisition step involves acquiring the pitch speed, the pitch angle, and the vertical speed based on an electrical signal from an inertial measuring device.

9. The road surface inclination state detection method according to claim 2, wherein the acquisition step calculates the pitch speed, the pitch angle, and the vertical speed based on an electrical signal from a stroke sensor.

10. The road surface inclination state detection method according to claim 2, wherein the acquisition step calculates the pitch speed, the pitch angle, and the vertical speed based on an electrical signal from an acceleration sensor.

11. The road surface inclination state detection method according to any one of claims 1 to 4 or any one of claims 8 to 10, wherein the inclination state detection step detects the inclination state when the speed of the vehicle is equal to or greater than a predetermined threshold.

12. An acquisition step to acquire the pitch speed of the vehicle, the pitch angle of the vehicle, and the vertical velocity of the vehicle's sprung mass, The acquisition step includes a counting step in which counting begins after the pitch speed, pitch angle, and vertical speed acquired in the acquisition step all exceed predetermined thresholds set corresponding to each of them, A ramp size calculation step calculates the ramp size when the road surface on which the vehicle is traveling is a ramp surface, according to the count value counted in the count step, A control step which controls the damping force of at least one of the front suspension and rear suspension of the vehicle according to the lamp size calculated in the lamp size calculation step, A vehicle control method equipped with the following features.

13. A calculation step in which the pitch velocity of the vehicle, the pitch angle of the vehicle, and the vertical velocity of the vehicle's sprung mass are calculated, and a high-pass filter is applied to reduce the offset and drift components in the pitch velocity, the pitch angle, and the vertical velocity. The calculation step involves applying the high-pass filter process to the pitch speed, pitch angle, and vertical speed, and the counting step begins after all of these exceed predetermined thresholds set accordingly. A tilt state detection step detects the tilt state of the road surface on which the vehicle is traveling, in accordance with the count value obtained in the count step, A control step that controls the damping force of at least one of the front suspension and rear suspension of the vehicle according to the tilt state detected in the tilt state detection step, A vehicle control method equipped with the following features.

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