Control system, saddled vehicle, control method, and program

Abstract

This control system for a saddled vehicle comprises: an estimation means for estimating, on the basis of a first force from an obstacle acting on a front wheel of the saddled vehicle, a second force from the obstacle acting on a rear wheel of the saddled vehicle; and a control means for controlling, when the rear wheel is affected by the obstacle and on the basis of the estimation result from the estimation means, a rear suspension mechanism that supports the rear wheel. The estimation means estimates, as the second force, a force that is converted from the first force in accordance with the difference in the state of the saddled vehicle when the front wheel is affected by the obstacle and when the rear wheel is affected by the obstacle.

Description

Control system, saddle-ride type vehicle, control method, and program

[0001] The present invention relates to a vehicle control technology.

[0002] Patent Document 1 discloses a technology that predicts the situation and timing of changes that may occur on the rear wheel side from the stroke displacement that occurs on the front wheel side, and controls the damping force of the rear suspension at an appropriate timing in response to that situation.

[0003] Japanese Unexamined Patent Publication No. 62-103215

[0004] In Patent Document 1, it is assumed that the load from the road surface is the same for the front and rear wheels, but the load from the road surface may differ between the front and rear wheels depending on the state of the saddle-ride type vehicle, such as the bank angle (roll angle) and acceleration. In this case, it becomes difficult to appropriately control the damping force of the rear suspension, which may reduce the handling stability and ride comfort of the saddle-ride type vehicle.

[0005] Therefore, an object of the present invention is to provide a technique that can improve the steering stability and riding comfort of a saddle-type vehicle.

[0006] In order to achieve the above object, one aspect of the present invention provides a control system for a saddle-riding vehicle, comprising: estimation means for estimating a second force acting from an obstacle on a rear wheel of the saddle-riding vehicle based on a first force acting from the obstacle on a front wheel of the saddle-riding vehicle; and control means for controlling a rear suspension mechanism supporting the rear wheel based on the estimation result of the estimating means when the rear wheel is affected by the obstacle, wherein the estimating means estimates as the second force a force converted from the first force in accordance with the difference in the state of the saddle-riding vehicle between when the front wheel is affected by the obstacle and when the rear wheel is affected by the obstacle.

[0007] According to the present invention, for example, it is possible to provide a technique that can improve the handling stability and riding comfort of a saddle-type vehicle.

[0008] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are designated by the same reference numerals.

[0009] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0010] 1 is a left side view showing a saddle-ride type vehicle according to a first embodiment; FIG. 2 is a diagram showing an example of the configuration of a control system according to the first embodiment; FIG. 3 is a diagram showing models of a front suspension mechanism and a rear suspension mechanism according to the first embodiment; FIG. 4 is a diagram for explaining estimation of a ground contact load (second force) of a rear wheel based on a ground contact load (first force) of a front wheel in the first embodiment; FIG. 5 is a diagram for explaining estimation of a ground contact load (second force) of a rear wheel based on a ground contact load (first force) of a front wheel in the first embodiment;

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and includes modifications and variations of the configuration within the scope of the present invention. Furthermore, not all of the combinations of features described in the present embodiments are necessarily essential to the present invention. Note that the same reference numerals are used to designate the same components, and their description will be omitted.

[0012] First Embodiment A first embodiment of the present invention will be described. FIG. 1 is a left side view showing a saddle-riding vehicle 1 according to this embodiment. In FIG. 1, arrows X, Y, and Z indicate directions that are perpendicular to one another, with the X direction indicating the front-to-rear direction of the saddle-riding vehicle 1, the Y direction indicating the width direction (left-to-right direction) of the saddle-riding vehicle 1, and the Z direction indicating the up-and-down direction of the saddle-riding vehicle 1. Below, an example will be described in which a control system according to the present invention is applied to a motorcycle as the saddle-riding vehicle 1. However, the control system according to the present invention can also be applied to other types of saddle-riding vehicles, such as tricycles, and can also be applied to electric vehicles using a motor as a drive source, in addition to vehicles using an internal combustion engine as a drive source. In the following, the saddle-riding vehicle 1 may also be referred to as a vehicle 1.

[0013] The vehicle 1 includes front wheels FW, rear wheels RW, and a power unit 2. The power unit 2 includes an engine 21 and a transmission 22. The driving force of the transmission 22 is transmitted to the rear wheels RW via a drive shaft (not shown), causing the rear wheels RW to rotate.

[0014] The power unit 2 is supported by a body frame 3. The body frame 3 includes a pair of left and right main frames 31 extending in the X direction. A fuel tank 5 and an air cleaner box (not shown) are disposed above the main frames 31. A meter unit MU that displays various information to the rider is provided in front of the fuel tank 5.

[0015] A head pipe 32 is provided at the front end of the main frame 31, rotatably supporting a steering shaft (not shown) that is turned by the handlebars 8. A pair of left and right pivot plates 33 is provided at the rear end of the main frame 31. The lower ends of the pivot plates 33 are connected to the front end of the main frame 31 by a pair of left and right lower arms (not shown), and the power unit 2 is supported by the main frame 31 and the lower arms. In addition, a pair of left and right seat rails (not shown) extending rearward are provided at the rear end of the main frame 31, and the seat rails support a seat 4a on which a rider sits, a seat 4b on which a passenger sits, a rear trunk 7b, etc.

[0016] The front end of a rear swing arm 34 extending in the fore-and-aft direction is rotatably attached to the pivot plate 33. A rear wheel RW is rotatably supported on the rear end of the rear swing arm 34. The rear swing arm 34 is configured to be able to swing up and down by a rear suspension mechanism 11 provided between the rear swing arm 34 and the body frame 3 (main frame 31). The rear suspension mechanism 11 can be configured as an electronically controlled suspension that can electronically control damping force. In addition, an exhaust muffler 6 that silences exhaust from the engine 21 is provided on either side of the rear wheel RW in the X direction. In addition, left and right saddlebags 7a are provided on either side of the rear wheel RW.

[0017] A front suspension mechanism 9 that supports a front wheel FW so that it can swing freely is configured at the front end of the main frame 31. The front suspension mechanism 9 can be configured as an electronically controlled suspension that can electronically control damping force. The front suspension mechanism 9 includes an upper link 91, a lower link 92, a fork support 93, a vibration reduction mechanism 94 (cushion unit), and a pair of left and right front forks 95. In the front suspension mechanism 9, the upper link 91, the lower link 92, the fork support 93, and the vibration reduction mechanism 94 form a support mechanism that supports the front forks 95 of the vehicle 1.

[0018] The upper link 91 and the lower link 92 are disposed above and below the front end of the main frame 31. The rear ends of the upper link 91 and the lower link 92 are pivotally connected to the front end of the main frame 31. The upper link 91 and the lower link 92 are pivotally connected to a fork support 93.

[0019] The fork support 93 is cylindrical and tilted backward. A steering shaft 96 is supported on the fork support 93 so as to be rotatable about its axis. The steering shaft 96 has a shaft portion (not shown) that passes through the fork support 93. A bridge (not shown) is provided at the lower end of the steering shaft 96, and a pair of left and right front forks 95 are supported on this bridge. The front forks 95 rotatably support the front wheel FW and also support the front brake FB. The upper end of the steering shaft 96 is connected via a link 97 to a steering shaft (not shown) that is rotated by the handlebars 8. The upper part of the front wheel FW is covered with a fender 10, which is supported by the front forks 95.

[0020] 2 is a diagram showing an example of the configuration of a control system 100 (control device) according to this embodiment. The control system 100 is a system that controls the suspension mechanisms (front suspension mechanism 9, rear suspension mechanism 11) of the vehicle 1, and may include a sensor group 110 and a processing unit 120. The control system 100 may also be configured as a system that controls only the rear suspension mechanism 11. In this case, the control system 100 may be configured only by the processing unit 120, without including the sensor group 110.

[0021] The sensor group 110 may include an inertial sensor 111, a stroke sensor 112, and a surrounding condition detection sensor 113. The inertial sensor 111 may be understood as a detection unit that detects the state of the vehicle 1.

[0022] The inertial sensor 111 includes an inertial measurement unit (IMU) that can detect the behavior of the vehicle 1 by detecting the acceleration and angular velocity occurring in the vehicle 1 (vehicle body). The inertial sensor 111 (IMU) is disposed at any appropriate location on the vehicle 1, for example, near the center of gravity of the vehicle 1. In this embodiment, the inertial sensor 111 detects translational acceleration in each of the X direction (front-rear direction), the Y direction (vehicle width direction), and the Z axis direction (up-down direction), and also detects angular velocity in each of the ωX direction, ωY direction, and ωZ direction. The ωX direction is the rotation direction around the X axis (roll direction), the ωY direction is the rotation direction around the Y axis (pitch direction), and the ωZ direction is the rotation direction around the Z axis (yaw direction). The inertial sensor 111 may also be configured to detect the speed of the vehicle 1 and the wheel speed of the vehicle 1.

[0023] The stroke sensor 112 detects the stroke speed of the front suspension mechanism 9 (front wheels FW) as a change in the state of the front suspension mechanism 9. The stroke sensor 112 may be configured to detect the stroke displacement of the front suspension mechanism 9 (front wheels FW). In the vehicle 1 of this embodiment, the stroke sensor 112 is only provided in the front suspension mechanism 9, and no stroke sensor is provided in the rear suspension mechanism 11. This reduces vehicle costs. In addition, the surrounding condition detection sensor 113 detects the surrounding conditions of the vehicle 1. In this embodiment, the surrounding condition detection sensor 113 includes a camera and / or radar (e.g., millimeter-wave radar) and can be configured to detect the conditions ahead of the vehicle 1. Note that the surrounding condition detection sensor 113 can be used in the second embodiment.

[0024] The processing unit 120 is, for example, an ECU (Electronic Control Unit) and may be configured by a computer including a processor such as a CPU, a storage device such as a semiconductor memory, an interface with external devices, etc. The storage device (memory) of the processing unit 120 stores application programs (hereinafter sometimes referred to as control programs) for controlling the front suspension mechanism 9 and the rear suspension mechanism 11 of the vehicle 1, and the processor of the processing unit 120 reads and executes the control programs stored in the storage device. The control programs include a program for estimating the force acting on the rear wheels RW of the vehicle 1 and controlling the rear suspension mechanism 11 based on the estimation results. The control programs may be stored in a storage medium such as a CD-ROM, a DVD, or a memory and installed in the processing unit 120 from the storage medium, or may be downloaded from an external server via a network and installed in the processing unit 120.

[0025] In this embodiment, the processing unit 120 may include an estimation unit 121 and a control unit (adjustment unit) 122. The estimation unit 121 estimates a second force acting on a rear wheel RW from an obstacle based on a first force acting on the front wheel FW from the obstacle. The estimation of the second force by the estimation unit 121 may be performed based on detection results from the sensor group 110. The control unit 122 controls the front suspension mechanism 9 and the rear suspension mechanism 11. Specifically, from the perspective of improving the steering stability and ride comfort of the vehicle 1, the control unit 122 performs so-called skyhook control, which controls (adjusts) the damping forces of the front suspension mechanism 9 and the rear suspension mechanism 11 using the skyhook theory, which assumes that the vehicle 1 (such as the vehicle body) is suspended in mid-air by a virtual line. In this embodiment, when the rear wheel RW is affected by an obstacle, the control unit 122 controls the rear suspension mechanism 11 based on the estimation result of the estimation unit 121.

[0026] 3 is a diagram showing a model of the front suspension mechanism 9 and the rear suspension mechanism 11 in this embodiment. The front suspension mechanism 9 and the rear suspension mechanism 11 are mechanisms for reducing vibrations transmitted from the road surface RS to the body BD of the vehicle 1. The front suspension mechanism 9 has an elastic member 9a and a viscous damping member 9b. Similarly, the rear suspension mechanism 11 has an elastic member 11a and a viscous damping member 11b.

[0027] The elastic members 9a and 11a have a spring constant. Springs, rubber, or the like may be used as the elastic members 9a and 11a, and in this embodiment, coil springs may be used. Furthermore, although not shown in detail, the viscous damping members 9b and 11b are monotube-type and may be configured using magnetorheological fluid (MRF) as the hydraulic fluid. A piston rod is axially slidably inserted into a cylindrical cylinder filled with MRF, and a piston attached to the tip of the piston rod divides the interior of the cylinder into an upper oil chamber and a lower oil chamber. When current is supplied to a coil located inside a communication passage connecting the upper and lower oil chambers, a magnetic field is applied to the MRF flowing through the communication passage, causing ferromagnetic particles to form clusters. This changes the viscosity of the MRF passing through the communication passage, thereby changing the damping force of the viscous damping members 9b and 11b. In other words, the control unit 122 can control (adjust) the damping force of the suspension mechanisms 9 and 11 by supplying current to the coils of the viscous damping members 9b and 11b and changing the viscosity of the magnetic fluid inside the viscous damping members 9b and 11b.

[0028] Here, the viscous damping members 9 b, 11 b are not limited to mechanisms using magnetorheological fluid (MRF), but may be mechanisms that adjust the damping force by varying the diameter of an orifice using a step motor or the like to change the amount of oil (hydraulic oil) passing through the orifice. In this case, the control unit 122 can change the diameter of the orifice of the viscous damping members 9 b, 11 b to change the amount of oil passing through the orifice, thereby controlling (adjusting) the damping force of the suspension mechanisms 9, 11.

[0029] In the control system 100, a stroke sensor 112 is provided in the front suspension mechanism 9, and the front suspension mechanism 9 is controlled by the control unit 122 based on the detection result of the stroke sensor 112 (i.e., the stroke speed detected by the stroke sensor 112). On the other hand, providing a stroke sensor in the rear suspension mechanism 11 may be disadvantageous in terms of vehicle cost. Therefore, the control system 100 estimates a second force acting on the rear wheel RW from the obstacle OB based on a first force acting on the front wheel FW from the obstacle OB (e.g., the stroke speed of the front suspension mechanism 9), and controls the rear suspension mechanism 11 based on the estimation result.

[0030] However, in the vehicle 1, depending on the state of the vehicle 1, such as the bank angle (roll angle) and acceleration, the load received from the obstacle OB may differ between the front wheels FW and the rear wheels RW. In this case, it becomes difficult to appropriately control (adjust) the damping force of the rear suspension mechanism 11, which may result in a decrease in the handling stability and ride comfort of the vehicle 1. Therefore, the control system 100 (estimation unit 121) of this embodiment estimates a second force acting on the rear wheels RW from the obstacle OB by converting the first force into a force corresponding to the difference in the state of the vehicle 1 between when the front wheels FW are affected by the obstacle OB and when the rear wheels RW are affected by the obstacle OB. By calculating the stroke speed that may be generated in the rear suspension mechanism 11 (rear wheels RW) due to the obstacle OB based on the estimated second force, the damping force of the rear suspension mechanism 11 can be appropriately controlled (adjusted). A method for calculating the stroke speed of the rear suspension mechanism 11 will now be described with reference to FIGS. 3 and 4A-4B. In this embodiment, the state of the vehicle 1 that differs when the front wheels FW are affected by an obstacle OB and when the rear wheels are affected by the obstacle OB will be described by taking as an example the bank angle (roll angle) of the vehicle 1. Note that the obstacle OB may be a convex or concave portion occurring on the road surface RS itself, such as an unevenness of the road surface RS, or may be an object placed or installed on the road surface RS.

[0031] [Method of Estimating Rear Stroke Speed] The stroke speed Vpf (hereinafter sometimes referred to as front stroke speed Vpf) generated in the front suspension mechanism 9 when the front wheel FW passes over the obstacle OB can be expressed by the following equation (1). "Vzf" in equation (1) represents the speed of the front part of the vehicle body BD in the vertical direction of the vehicle 1, and may be referred to as the "front body speed Vzf" below. When the front suspension mechanism 9 is considered as a spring, the front body speed Vzf may be understood as the speed of the sprung mass. Furthermore, "Vzwf" in equation (1) represents the speed of the front wheel FW in the vertical direction of the vehicle 1, and may be referred to as the "front wheel speed Vzwf" below. When the front suspension mechanism 9 is considered as a spring, the front wheel speed Vzwf may be understood as the speed of the unsprung mass. Vpf = Vzf - Vzwf (1)

[0032] The front vehicle body speed Vzf is expressed by the following equation (2). "Vz" in equation (2) represents the vertical speed of the vehicle body BD when the front wheel FW is affected by the obstacle OB, and can be obtained from the detection result of the inertial sensor 111. In this embodiment, the inertial sensor 111 is configured to detect the vertical acceleration Gz. Therefore, the speed Vz can be obtained by integrating the acceleration Gz detected by the inertial sensor 111. "Lf" in equation (2) represents the distance between the front suspension mechanism 9 and the inertial sensor 111 in the longitudinal direction of the vehicle 1. The distance Lf can be the horizontal distance between the axle position of the front wheel (front wheel FW) and a representative position of the inertial sensor 111 (e.g., a position serving as a measurement reference for acceleration and angular velocity, the center of gravity). The distance Lf is a known value. Furthermore, "ωy" in equation (2) represents the angular velocity in the pitch direction (ωy direction) detected by the inertial sensor 111 when the rear wheel RW is affected by the obstacle OB. Vzf=Vz-Lf*ωy (2)

[0033] Note that the vehicle 1 may be provided with a vertical speed sensor that detects only the vertical speed of the vehicle body BD instead of the inertial sensor 111. In this case, the vertical speed detected by the vertical speed sensor may be applied to "Vz" in equation (2). If a vertical acceleration sensor that detects only the vertical acceleration of the vehicle body BD is provided instead of the inertial sensor 111, the integral value of the vertical acceleration detected by the vertical acceleration sensor may be applied to "Vz" in equation (2). Furthermore, the vehicle 1 may be provided with a pitch angular velocity sensor that detects only the angular velocity in the pitch direction instead of the inertial sensor 111. In this case, the pitch angular velocity detected by the pitch angular velocity sensor may be applied to "ωy" in equation (2).

[0034] The front wheel speed Vzwf is expressed by the following equation (3). "Fzf" in equation (3) represents the first force acting on the front wheel FW from the obstacle OB, and may be referred to as the ground load Fzf of the front wheel FW hereinafter. Furthermore, "Mf" in equation (3) represents the front unsprung mass (specifically, the mass or weight including the front wheel FW (front wheel) as well as a part of the front suspension mechanism 9). The mass Mf of the front wheel FW is a known value. The front wheel speed Vzwf is calculated by integrating the value obtained by dividing the ground load Fzf of the front wheel FW by the mass Mf of the front wheel FW. Vzwf = ∫Fzf / Mfdt (3)

[0035] By substituting equations (2) and (3) into equation (1), the following equation (4) is obtained. In equation (4), the front stroke speed Vpf is obtained from the detection result of the stroke sensor 112, and the speed Vz and angular speed ωy are obtained from the detection result of the inertial sensor 111. In addition, the distance Lf and the mass Mf are known values. Therefore, the ground contact load Fzf of the front wheel FW can be calculated from equation (4). Vpf = (Vz - Lf * ωy) - (∫Fzf / Mfdt) (4)

[0036] Next, a second force estimated to act on the rear wheel RW from the obstacle OB is calculated based on the ground load Fzf of the front wheel FW. Hereinafter, the second force may be referred to as the ground load Fzr of the rear wheel RW. Specifically, as shown in FIG. 4A , a reference force vector Fz is calculated based on the ground load Fzf of the front wheel FW. The reference force vector Fz represents a force in a reference direction and, in this embodiment, may be set as a force in the vertical direction. The reference force vector Fz may be expressed by equation (5) based on the ground load Fzf of the front wheel FW. "φ1" in equation (5) represents the roll angle of the vehicle 1 when the front wheel FW is affected by the obstacle OB, i.e., the roll angle of the front wheel FW, and is obtained by differentiating the roll angular velocity ωx detected by the inertial sensor 111. Note that the vehicle 1 may be provided with a bank angle sensor that detects the bank angle of the vehicle 1 instead of the inertial sensor 111. In this case, the bank angle (roll angle) detected by the bank angle sensor can be applied to "φ1" in equation (5). Fz=Fzf / cos(φ1) (5)

[0037] On the other hand, the second force (rear wheel RW ground load Fzr) estimated to act on the rear wheel RW from the obstacle OB is estimated (calculated) based on the reference force vector Fz calculated using equation (5), as shown in FIG. 4B . That is, the rear wheel RW ground load Fzr is estimated (calculated) using equation (6) on the assumption that the reference force vector Fz is the same when the front wheel FW is affected by the obstacle OB and when the rear wheel RW is affected by the obstacle OB. "φ2" in equation (6) represents the bank angle of the vehicle 1 when the rear wheel RW is affected by the obstacle OB, i.e., the roll angle of the rear wheel RW, and is obtained by differentiating the roll angular velocity ωx detected by the inertial sensor 111. Note that the vehicle 1 may be provided with a bank angle sensor that detects the bank angle of the vehicle 1 instead of the inertial sensor 111. In this case, the bank angle (roll angle) detected by the bank angle sensor may be applied to "φ2" in equation (6). Fzr=Fz×cos(φ2)...(6)

[0038] Next, a stroke speed Vpr (hereinafter sometimes referred to as rear stroke speed Vpr) estimated to occur in the rear suspension mechanism 11 when the rear wheel RW is affected by the obstacle OB is calculated. The rear stroke speed Vpr can be calculated using the following equation (7). "Vzr" in equation (7) represents the speed of the rear part of the vehicle body BD in the vertical direction of the vehicle 1, and may be referred to as the "rear body speed Vzr" below. When the rear suspension mechanism 11 is considered as a spring, the rear body speed Vzr may be understood as the speed of the sprung mass. Furthermore, "Vzwr" in equation (7) represents the speed of the rear wheel RW in the vertical direction of the vehicle 1, and may be referred to as the "rear wheel speed Vzwr" below. When the rear suspension mechanism 11 is considered as a spring, the rear wheel speed Vzwr may be understood as the speed of the unsprung mass. Vpr = Vzr - Vzwr (7)

[0039] The rear vehicle body speed Vzr is expressed by the following equation (8). "Vz" in equation (8) represents the vertical speed of the vehicle body BD when the rear wheel RW is affected by the obstacle OB, and can be obtained from the detection result of the inertial sensor 111. In this embodiment, the inertial sensor 111 is configured to detect the vertical acceleration Gz. Therefore, the speed Vz can be obtained by integrating the acceleration Gz detected by the inertial sensor 111. "Lr" in equation (8) represents the distance between the rear suspension mechanism 11 and the inertial sensor 111 in the longitudinal direction of the vehicle 1. The distance Lr can be the horizontal distance between the axle position of the rear wheel (rear wheel RW) and a representative position of the inertial sensor 111 (e.g., a position serving as a measurement reference for acceleration and angular velocity, the center of gravity). The distance Lr is a known value. Furthermore, "ωy" in equation (8) represents the angular velocity in the pitch direction (ωy direction) detected by the inertial sensor 111 when the rear wheel RW is affected by the obstacle OB. Vzr=Vz+Lr*ωy (8)

[0040] The rear wheel speed Vzwr is expressed by the following equation (9). "Fzr" in equation (9) represents the second force (ground contact load of rear wheel RW) estimated to act on rear wheel RW from obstacle OB, and is the value obtained by the above equation (6). Furthermore, "Mr" in equation (9) represents the rear wheel unsprung mass (specifically, the mass or weight including the rear wheel RW (rear wheel) as well as a part of the rear suspension mechanism 11). The mass Mr of rear wheel RW is a known value. The rear wheel speed Vzwr is calculated by integrating the value obtained by dividing the ground contact load Fzr of rear wheel RW by the mass Mr of rear wheel RW. Vzwr = ∫Fzr / Mrdt (9)

[0041] By substituting equations (8) and (9) into equation (7), the following equation (10) is obtained. In equation (10), the velocity Vz and angular velocity ωy are obtained from the detection results of the inertial sensor 111. The distance Lr and mass Mr are known values. The ground load Fzr of the rear wheel RW is estimated (calculated) using equation (6) above. Therefore, the rear stroke speed Vpr can be estimated (calculated) using equation (10). This allows the control unit 122 to control (adjust) the damping force of the rear suspension mechanism 11 based on the estimated rear stroke speed Vpr. Vpr = (Vz + Lr * ωy) - (∫Fzr / Mrdt) ... (10)

[0042] [Control of Rear Suspension Mechanism] Next, a control method for the rear suspension mechanism 11 in this embodiment will be described. Fig. 5 is a flowchart showing a control method for the rear suspension mechanism 11 in this embodiment. The flowchart in Fig. 5 can be executed by the processing unit 120 (estimation unit 121, control unit 122). Note that the flowchart in Fig. 5 can be executed repeatedly. That is, after step SS19 is completed, the process starts again from step S10.

[0043] Steps S10 to S14 are steps for determining a reference force vector Fz based on the first force applied to the front wheel FW from the obstacle OB.

[0044] In step S10, the processing unit 120 acquires a front stroke speed Vpf based on the detection result of the stroke sensor 112. In step S11, the processing unit 120 acquires a roll angle φ1 of the front wheels FW based on the calculation result using information from the inertial sensor 111. Next, in step S12, the processing unit 120 acquires the vertical acceleration Gz and the pitch angular velocity ωy of the vehicle body BD based on the detection result of the inertial sensor 111. The acceleration Gz acquired in step S12 is converted into a velocity Vz by integration. Here, the processing unit 120 may perform high-pass filtering on each piece of information acquired in steps S10 to S12 to remove vibration components (low-frequency components) caused by the movement of the vehicle body BD and the engine 21.

[0045] In step S13, the processing unit 120 calculates the ground contact load Fzf (first force) acting on the front wheels FW from the obstacle OB using the above equation (4) based on the front stroke speed Vpf acquired in step S10 and the speed Vz and angular speed ωy acquired in step S12. Next, in step S14, the processing unit 120 calculates the reference force vector Fz using the above equation (5) based on the roll angle φ1 acquired in step S11 and the ground contact load Fzf of the front wheels FW calculated in step S13.

[0046] Steps S15 to S18 are steps for estimating the second force that the rear wheel RW receives from the obstacle OB, and estimating the rear stroke speed Vpr based on the estimation result.

[0047] In step S15, the processing unit 120 acquires the roll angle φ2 of the rear wheels RW based on the calculation results using information from the inertial sensor 111. Next, in step S16, the processing unit 120 acquires the vertical acceleration Gz and the pitch angular velocity ωy of the vehicle body BD based on the detection results of the inertial sensor 111. The acceleration Gz acquired in step S16 is converted into a velocity Vz by integration.

[0048] In step S17, the processing unit 120 (estimation unit 121) calculates the ground contact load Fzr (second force) estimated to act on the rear wheel RW from the obstacle OB using the above equation (6) based on the reference force vector Fz obtained in step S14 and the roll angle φ2 of the rear wheel RW acquired in step S15.

[0049] In step S18, the processing unit 120 (estimation unit 121) estimates (calculates) the rear stroke speed Vpr using the above equation (10) based on the speed Vz and angular speed ωy acquired in step S16 and the ground load Fzr of the rear wheel RW acquired in step S17. Next, in step S19, the processing unit 120 (control unit 122) controls (adjusts) the damping force of the rear suspension mechanism 11 based on the rear stroke speed Vpr estimated in step S18. Here, the processing unit 120 may perform high-pass filtering on each piece of information acquired in steps S15 to S16 to remove vibration components (low-frequency components) resulting from the movement of the vehicle body BD and engine 21. Alternatively, the speed Vz and angular speed ωy acquired in step S12 may be used in step S18. In this case, step S16 may be omitted.

[0050] As described above, the control system 100 of this embodiment estimates a second force (ground contact load Fzr) acting on the rear wheel RW from the obstacle OB by converting the first force (ground contact load Fzf) depending on the difference in the state of the vehicle 1 between when the front wheel FW is affected by the obstacle OB and when the rear wheel is affected by the obstacle OB. The control system 100 then controls the rear suspension mechanism 11 based on the estimated second force. This makes it possible to appropriately control the damping force of the rear suspension mechanism 11 in real time without providing a stroke sensor in the rear suspension mechanism 11. This is advantageous in terms of vehicle cost and can improve the handling stability and ride comfort of the saddle-ride type vehicle 1.

[0051] Second Embodiment A second embodiment of the present invention will be described. This embodiment basically follows on from the first embodiment, and can follow the first embodiment except for the matters mentioned below.

[0052] In the saddle-ride type vehicle 1, for example, when turning a curve, a difference (i.e., an inner wheel difference) may occur between the trajectory of the front wheels FW and the trajectory of the rear wheels RW, and the influence of the obstacle OB may differ between the front wheels FW and the rear wheels RW. Therefore, simply estimating the influence of the obstacle OB on the rear wheels RW (second force) based on the influence of the obstacle OB on the front wheels FW (first force) without considering the difference in the influence of the obstacle OB on the front wheels FW and the rear wheels RW may not be sufficient to accurately control the rear suspension mechanism 11. Therefore, in this embodiment, the estimating unit 121 identifies the position and / or shape of the obstacle OB based on the detection results of the surrounding condition detection sensor 113 and calculates the influence degree of the obstacle OB on each of the front wheels FW and the rear wheels RW. Then, the estimating unit 121 corrects the ground load Vpr (second force) acting from the obstacle OB on the rear wheels RW according to the influence degree calculated for each of the front wheels FW and the rear wheels RW. This allows the rear suspension mechanism 11 to be controlled with high precision.

[0053] For example, the influence of the obstacle OB is calculated as an index determined according to the location (portion, position) of the obstacle OB through which each of the front wheels FW and the rear wheels RW passes. The estimation unit 121 identifies the position of the obstacle OB based on the detection results of the surrounding condition detection sensor 113, and determines (calculates) the trajectories of the front wheels FW and the rear wheels RW on the road surface RS. The estimation unit 121 then determines a first location of the obstacle OB through which the front wheels FW pass and a second location of the obstacle OB through which the rear wheels RW pass. This makes it possible to calculate (estimate) the influence of the first location of the obstacle OB on the front wheels FW and the influence of the second location of the obstacle OB on the rear wheels RW.

[0054] As an example, assume that the front wheels FW pass through the center (first location) of an obstacle OB, and the rear wheels FW pass through the edge (second location) of the obstacle OB. In this case, the ratio of the degree of influence when the wheels pass through the center of the obstacle OB to the degree of influence when the wheels pass through the edge of the obstacle OB is set to "1 / α" (e.g., 1 / 2) through experiments, simulations, etc. In this case, the estimation unit 121 multiplies the reference force vector Fz calculated based on the ground load Fzf (first force) of the front wheels FW by 1 / α as shown in FIG. 6A, and estimates (calculates) the ground load Fzr (second force) of the rear wheels RW based on Fz / α as shown in FIG. 6B. In this way, the ground load Fzr (second force) of the rear wheels RW is corrected according to the degree of influence of the obstacle OB on each of the front wheels FW and the rear wheels RW.

[0055] Here, the influence of the obstacle OB may be calculated as an index determined according to the contact area (ground contact area) between each of the front wheel FW and the rear wheel RW and the obstacle OB. In this case, the coefficient "1 / α" may be set (determined) as the ratio of the contact area between the rear wheel RW and the obstacle OB to the contact area between the front wheel FW and the obstacle OB. Furthermore, the influence of the obstacle OB may be calculated as an index determined according to the height of the location of the obstacle OB that each of the front wheel FW and the rear wheel RW passes over. In this case, the coefficient "1 / α" may be set (determined) as the ratio of the height of the location of the obstacle OB that each of the front wheel FW and the rear wheel RW passes over to the height of the location of the obstacle OB that each of the front wheel FW passes over.

[0056] Third Embodiment A third embodiment of the present invention will be described. This embodiment basically follows the first embodiment, and may follow the first embodiment except for the matters mentioned below. In addition, the second embodiment may also be applied to this embodiment.

[0057] When the height h of the obstacle OB can be obtained based on the detection result of the surrounding condition detection sensor 113, the estimation unit 121 can calculate the ground load Fzf of the front wheels FW and the ground load Fzr of the rear wheels RW using the following equation (11). In equation (11), the ground load Fzf can be calculated by the second differentiation of "h / cosφ1", and the ground load Fzr can be calculated by the second differentiation of "h / cosφ2". Fzf=Mf*d ２ (h / cosφ1) / dt ２ Fzr = Mr * d ２ (h / cosφ2) / dt ２ ...(11)

[0058] Summary of the Embodiments 1. The control system of the above embodiment is a control system (e.g., 100) for a saddle-riding type vehicle (e.g., 1), comprising: estimation means (e.g., 121) that estimates a second force (e.g., Fzr) acting from an obstacle (e.g., OB) on a rear wheel (e.g., RW) of the saddle-riding type vehicle based on a first force (e.g., Fzf) acting from the obstacle on a front wheel (e.g., FW) of the saddle-riding type vehicle; and control means (e.g., 122) that controls a rear suspension mechanism (e.g., 11) that supports the rear wheel based on the estimation result of the estimation means when the rear wheel is affected by the obstacle, wherein the estimation means estimates as the second force a force converted from the first force in accordance with a difference in the state of the saddle-riding type vehicle between when the front wheel is affected by the obstacle and when the rear wheel is affected by the obstacle. According to this embodiment, the rear suspension mechanism can be controlled appropriately and in real time without providing a stroke sensor in the rear suspension mechanism. This is advantageous in terms of vehicle costs, and also improves the steering stability and riding comfort of the saddle-type vehicle.

[0059] 2. In the above embodiment, the state of the saddle riding type vehicle includes a roll angle of the saddle riding type vehicle. According to this embodiment, the rear suspension mechanism can be appropriately controlled in accordance with the difference in roll angle of the saddle riding type vehicle between when the front wheel is affected by an obstacle and when the rear wheel is affected by the obstacle.

[0060] 3. In the above embodiment, the estimation means estimates the second force based on the first force, the roll angle of the saddle riding type vehicle when the front wheel is affected by the obstacle (e.g., φ1), and the roll angle of the saddle riding type vehicle when the rear wheel is affected by the obstacle (e.g., φ2). According to this embodiment, the second force that the rear wheel will receive from the obstacle can be accurately estimated from the first force that the front wheel receives from the obstacle, depending on the difference in the roll angle of the saddle riding type vehicle when the front wheel is affected by the obstacle and when the rear wheel is affected by the obstacle.

[0061] 4. In the above embodiment, the vehicle further includes first detection means (e.g., 113) that detects the surrounding conditions of the saddle-riding type vehicle, and the estimation means identifies the position and / or shape of the obstacle based on the detection result of the first detection means, calculates the degree of influence of the obstacle on each of the front wheels and the rear wheels, and corrects the second force in accordance with the calculated degree of influence for each of the front wheels and the rear wheels. According to this embodiment, the second force acting from the obstacle on the rear wheels can be appropriately corrected in accordance with the degree of influence of the obstacle on each of the front wheels and the rear wheels, making it possible to control the rear suspension mechanism with greater precision.

[0062] 5. In the above embodiment, the degree of influence is an index determined depending on the location of the obstacle through which each of the front wheels and the rear wheels passes. According to this embodiment, the second force acting from the obstacle to the rear wheels can be appropriately corrected depending on the degree of influence of the obstacle on each of the front wheels and the rear wheels, thereby enabling more accurate control of the rear suspension mechanism.

[0063] 6. In the above embodiment, the degree of influence is an index determined according to the contact area between each of the front wheels and the rear wheels and the obstacle. According to this embodiment, the second force acting from the obstacle to the rear wheels can be appropriately corrected according to the degree of influence of the obstacle on each of the front wheels and the rear wheels, thereby enabling more accurate control of the rear suspension mechanism.

[0064] 7. In the above embodiment, the degree of influence is an index determined according to the height of the obstacle at a location where each of the front wheels and the rear wheels passes. According to this embodiment, the second force acting from the obstacle to the rear wheels can be appropriately corrected according to the degree of influence of the obstacle on each of the front wheels and the rear wheels, thereby enabling more accurate control of the rear suspension mechanism.

[0065] 8. In the above embodiment, the vehicle further includes second detection means (e.g., 112) that detects a change in the state of a front suspension mechanism (e.g., 9) that supports the front wheels, and the estimation means determines the first force based on the detection result of the second detection means. According to this embodiment, the first force acting on the front wheels from an obstacle can be appropriately determined.

[0066] 9. In the above embodiment, the vehicle further includes a third detection means (e.g., 111) that detects the state of the saddle riding type vehicle, and the estimation means estimates the second force based on the detection result of the third detection means. According to this embodiment, the second force acting on the front wheel from an obstacle can be accurately estimated.

[0067] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

[0068] This application claims priority based on Japanese Patent Application No. 2023-059053, filed on March 31, 2023, the entire contents of which are incorporated herein by reference.

[0069] 1: saddle-ride type vehicle, 9: front suspension mechanism, 11: rear suspension mechanism, FW: front wheel, RW: rear wheel, BD: vehicle body, RS: road surface, OB: obstacle, 111: inertia sensor, 112: stroke sensor, 113: surrounding condition detection sensor, 120: processing unit, 121: estimation unit, 122: control unit (adjustment unit)

Claims

1. A control system for a saddle-ride type vehicle, an estimation means for estimating a second force acting on a rear wheel of the saddle riding type vehicle from an obstacle based on a first force acting on a front wheel of the saddle riding type vehicle from the obstacle; a control means for controlling a rear suspension mechanism supporting the rear wheels based on the estimation result of the estimation means when the rear wheels are affected by the obstacle; Equipped with the estimating means estimates, as the second force, a force converted from the first force in accordance with a difference in a state of the saddle-riding type vehicle between when the front wheel is affected by the obstacle and when the rear wheel is affected by the obstacle.

2. 2. The control system according to claim 1, wherein the state of the saddle-ride type vehicle includes a roll angle of the saddle-ride type vehicle.

3. 3. The control system according to claim 2, wherein the estimating means estimates the second force based on the first force, a roll angle of the saddle-riding type vehicle when the front wheel is affected by the obstacle, and a roll angle of the saddle-riding type vehicle when the rear wheel is affected by the obstacle.

4. a first detection means for detecting a surrounding situation of the saddle riding type vehicle; The estimation means Identifying the position and / or shape of the obstacle based on the detection result of the first detection means, and calculating the degree of influence of the obstacle on each of the front wheels and the rear wheels; 2. The control system according to claim 1, wherein the second force is corrected in accordance with the degree of influence calculated for each of the front wheels and the rear wheels.

5. 5. The control system according to claim 4, wherein the degree of influence is an index determined depending on a location of the obstacle that each of the front wheels and the rear wheels passes.

6. 5. The control system according to claim 4, wherein the degree of influence is an index determined according to a contact area between each of the front wheels and the rear wheels and the obstacle.

7. 5. The control system according to claim 4, wherein the degree of influence is an index determined according to the height of the obstacle at a location where each of the front wheels and the rear wheels passes.

8. a second detection means for detecting a change in the state of a front suspension mechanism supporting the front wheels; 2. The control system according to claim 1, wherein the estimating means determines the first force based on the detection result of the second detecting means.

9. a third detection means for detecting a state of the saddle riding type vehicle; 2. The control system according to claim 1, wherein the estimation means estimates the second force based on the detection result of the third detection means.

10. A straddle-type vehicle comprising the control system according to any one of claims 1 to 9.

11. A control method for a saddle-ride type vehicle, comprising: an estimation step of estimating a second force acting from an obstacle on a rear wheel of the saddle riding type vehicle based on a first force acting from the obstacle on a front wheel of the saddle riding type vehicle; a control step of controlling a rear suspension mechanism supporting the rear wheels based on the estimation result when the rear wheels are affected by the obstacle; Equipped with a control method characterized in that in the estimation step, a force converted from the first force in accordance with a difference in a state of the saddle-riding type vehicle between when the front wheel is affected by the obstacle and when the rear wheel is affected by the obstacle is estimated as the second force.

12. A program for causing a computer to execute the control method according to claim 11.