Rider assistance system and control method

Abstract

The purpose of the invention is to appropriately stabilize a vehicle body orientation while preventing the interior of an accumulator from being filled with brake fluid. In a rider assistance system and control method according to the present invention, the rider assistance system comprises a hydraulic pressure control unit, and a control device including an execution unit that executes pressure control in which a pressure reduction operation for reducing the pressure of brake fluid of a wheel cylinder is executed by releasing the brake fluid from the wheel cylinder to an accumulator. The fluid pressure control unit is not provided with a pump for discharging the brake fluid that has accumulated in the accumulator from the accumulator. In pressure control, when remaining capacity information pertaining to the accumulator indicates that the remaining capacity of the accumulator is low, the execution unit executes an intervention suppression operation that makes it more difficult to intervene in the pressure reduction operation than when the remaining capacity information indicates that the remaining capacity is high.

Description

[0001] [Document name] Statement

[0002] [Title of invention] Rider assistance system and control method

[0003] [Technical Field]

[0004] [. 0 0 1] This disclosure relates to a rider assistance system and a control method that can appropriately stabilize the vehicle body posture while preventing the accumulator from becoming full with brake fluid.

[0005] [Background technology]

[0006] [. 0 0 2] Lean vehicles are equipped with a mechanism for controlling the braking force acting on the wheels, such as a hydraulic control unit that controls the pressure of the brake fluid in the wheel cylinder (see, for example, Patent Document 1).

[0007] [Prior art documents]

[0008] [Patent documents]

[0009]

〇 0 0 3

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-8674

[0011] Summary of the Invention

[0012] [Problem to be solved by the invention]

[0013]

[0004] In a brake system including a hydraulic control unit, a pressure reduction operation is performed to reduce the pressure of the brake fluid in the wheel cylinder by releasing the brake fluid from the wheel cylinder to the accumulator. This pressure reduction operation can, for example, stabilize the vehicle posture by suppressing wheel slippage.

[0014]

[0005] Here, as in the hydraulic control unit disclosed in Patent Document 1, the hydraulic control unit may be provided with a pump that discharges brake fluid accumulated in the accumulator from the accumulator. In that case, while the brake operation continues, the pump can discharge the brake fluid accumulated in the accumulator by reducing the pressure.

[0015] [0 0 6] On the other hand, there are cases where the above-mentioned pump is not provided in the hydraulic control unit. In such cases, the brake fluid accumulated in the accumulator cannot be discharged until the brake operation is released, and the amount of brake fluid accumulated in the accumulator increases each time a pressure reduction operation is performed. Therefore, the accumulator is likely to become filled with brake fluid. When this happens, a situation may arise in which the pressure reduction operation cannot be performed. Therefore, one possible measure to resolve this situation is to make it more difficult to initiate the pressure reduction operation. However, simply making it more difficult to initiate the pressure reduction operation may result in excessive suppression of the pressure reduction operation, which could reduce the stability of the vehicle's posture.

[0016]

[0007] The present invention has been made against the background of the above-mentioned problems, and aims to provide a rider assistance system and control method that can appropriately stabilize the vehicle posture while preventing the accumulator from becoming filled with brake fluid.

[0017] [Means for solving the problem]

[0018]

[0008] A rider assistance system according to the present invention is a rider assistance system that assists a rider of a lean vehicle in driving, and comprises: a hydraulic control unit that includes an accumulator and controls the pressure of brake fluid in a wheel cylinder of the lean vehicle; and a control device that includes an execution unit that executes pressure control to execute a pressure reducing operation to reduce the pressure of the brake fluid in the wheel cylinder by releasing brake fluid from the wheel cylinder to the accumulator, wherein the hydraulic control unit is not provided with a pump that discharges brake fluid accumulated in the accumulator from the accumulator, and the execution unit executes an intervention suppression operation that makes it more difficult to intervene in the pressure reducing operation when the remaining capacity information of the accumulator is information indicating that the remaining capacity of the accumulator is low, compared to when the remaining capacity information is information indicating that the remaining capacity is high.

[0019]

[0009] A control method according to the present invention is a control method for a rider assistance system that assists a rider of a lean vehicle in driving, the rider assistance system comprising: a hydraulic control unit including an accumulator and controlling the pressure of brake fluid in a wheel cylinder of the lean vehicle; and a control device including an execution unit that executes pressure control to execute a pressure reducing operation to reduce the pressure of the brake fluid in the wheel cylinder by releasing brake fluid from the wheel cylinder to the accumulator, wherein the hydraulic control unit is not provided with a pump that discharges brake fluid accumulated in the accumulator from the accumulator, and the execution unit executes an intervention suppression operation in the pressure control that makes it less likely to intervene in the pressure reducing operation when the remaining capacity information of the accumulator indicates that the remaining capacity of the accumulator is low, compared to when the remaining capacity information indicates that the remaining capacity is high.

[0020] [Effects of the Invention]

[0021]

[0010] In the rider assistance system and control method according to the present invention, the rider assistance system includes a hydraulic control unit including an accumulator and controlling the pressure of brake fluid in the wheel cylinder of a lean vehicle, and a control device including an execution unit that executes pressure control to execute a pressure reducing operation to reduce the pressure of the brake fluid in the wheel cylinder by releasing the brake fluid from the wheel cylinder to the accumulator, wherein the hydraulic control unit is not provided with a pump that discharges the brake fluid accumulated in the accumulator from the accumulator, and the execution unit executes an intervention suppression operation in the pressure control to make it more difficult to intervene in the pressure reducing operation when the remaining capacity information of the accumulator indicates that the remaining capacity of the accumulator is low compared to when the remaining capacity information indicates that the remaining capacity is high. As a result, by executing the intervention suppression operation, it is possible to prevent the accumulator from becoming full of brake fluid. Furthermore, the intervention suppression operation makes it more difficult for the pressure-reducing operation to intervene as the remaining capacity of the accumulator decreases. Therefore, excessive suppression of the pressure-reducing operation can be prevented when the remaining capacity of the accumulator is high, and the vehicle posture can be appropriately stabilized. As described above, the rider assistance system and control method according to the present invention can appropriately stabilize the vehicle posture while preventing the accumulator from becoming filled with brake fluid.

[0022] [Brief explanation of the drawings]

[0023] [ 0 0 1 1 ]

[0024] [Figure 1] Schematic diagram showing the general configuration of a lean vehicle according to an embodiment of the present invention.

[0025] [Figure 2] Schematic diagram showing the general configuration of a brake system according to an embodiment of the present invention.

[0026] [Figure 3] A block diagram showing an example of the functional configuration of a control device according to an embodiment of the present invention.

[0027] [Figure 4] A flowchart showing a first example of the processing flow performed by a control device according to an embodiment of the present invention.

[0028] [Figure 5] A graph showing an example of the relationship between remaining capacity and water content in an embodiment of the present invention.

[0029] [Figure 6] A flowchart showing a second example of the processing flow performed by a control device according to an embodiment of the present invention.

[0030] [Figure 7] A flowchart showing a third example of the processing flow performed by a control device according to an embodiment of the present invention.

[0031] DETAILED DESCRIPTION OF THE INVENTION

[0032]

[0012] Hereinafter, a rider assistance system and a control method according to the present invention will be described with reference to the drawings.

[0033]

[0013] In the following, we will refer to the rider assistance system used for bicycles (see lean vehicle 1 in Figure 1). , front wheel speed sensor 22 and inertial measurement unit 23).

[0034]

[0019] The frame 11 includes, for example, a head tube 11a, a top tube 11b, a down tube 11c, a seat tube 11d, and a stay 11e. The head tube 11a pivotally supports a steering column 12a of a turning unit 12 (described below). The top tube 11b and the down tube 11c are each connected to the head tube 11a. The seat tube 11d spans between the top tube 11b and the down tube 11c and holds a saddle. The stay 11e is connected to the upper and lower ends of the seat tube 11d and holds a rear wheel 14 and a rear wheel braking unit 17. The rear wheel braking unit 17 is attached to the rear wheel 14 and applies braking force to the rear wheel 14.

[0035]

[0020] The turning unit 12 includes a steering column 12a, a handle stem 12b, a handlebar 12c, and a front fork 12d. The steering column 12a is journaled on the head tube 11a and is rotatable relative to the head tube 11a. The handle stem 12b is held by the steering column 12a. The handlebar 12c is held by the handle stem 12b. A brake operating unit 15 is attached to the handlebar 12c. The front fork 12d is connected to the steering column 12a. A front wheel 13 is rotatably held by the front fork 12d. The front wheel braking unit 16 is attached to the front wheel 13 and applies a braking force to the front wheel 13. Front forks 12d are provided on both sides of the front wheel 13. One end of the front fork 12d is connected to the steering column 12a, and the other end of the front fork 12d is connected to the center of rotation of the front wheel 13. In other words, the front wheel 13 is rotatably held between the pair of front forks 12d. The front forks 12d may be front forks with suspension.

[0036]

[0021] The brake operating unit 15 includes a mechanism used as an operating unit for the front wheel braking unit 16 and a mechanism used as an operating unit for the rear wheel braking unit 17. For example, the mechanism used as the operating unit for the front wheel braking unit 16 is disposed on the right end side of the handlebar 12 c, and the mechanism used as the operating unit for the rear wheel braking unit 17 is disposed on the left end side of the handlebar 12 c.

[0037]

[0022] The hydraulic pressure control unit 18 is held by the front fork 12d of the turning section 12. However, the installation position of the hydraulic pressure control unit 18 is not limited to the example of FIG. 1. For example, the hydraulic pressure control unit 18 may be provided on the steering column 12a, the handlebar 12c, the top tube 11b, the down tube 11c, etc. The hydraulic pressure control unit 18 is a unit that controls the hydraulic pressure of the brake fluid in the front wheel braking section 16. Note that the rear wheel braking section 17 may be a braking section that generates braking force by increasing the hydraulic pressure of the brake fluid, or may be a braking section that generates braking force mechanically (for example, a braking section that generates braking force by generating tension in a wire, etc.). Details of the brake system 10 including the hydraulic control unit 18 will be described later.

[0038]

[0023] The input device 21 accepts various operations by the rider. The input device 21 is provided on the handlebar 12 c, for example, and includes push buttons and the like used for rider operation.

[0039]

[0024] The front wheel speed sensor 22 is a wheel speed sensor that detects the wheel speed of the front wheel 13 (for example, the number of rotations per unit time [rpm] of the front wheel 13 or the distance traveled per unit time [km / h], etc.) and outputs the detection result. The front wheel speed sensor 22 may also detect other physical quantities that can be substantially converted into the wheel speed of the front wheel 13. The front wheel speed sensor 22 is provided on the front wheel 13.

[0040]

[0025] The inertial measurement unit 23 is equipped with a three-axis gyro sensor and a three-directional acceleration sensor, and detects the attitude of the lean vehicle 1. In the example of FIG. 1, the inertial measurement unit 23 is provided on the down tube 11c. However, the installation position of the inertial measurement unit 23 is not limited to the example of FIG. 1. For example, the inertial measurement unit 23 detects the pitch angle of the lean vehicle 1 relative to the horizontal direction and outputs the detection result. The inertial measurement unit 23 may also detect other physical quantities that can be substantially converted into the pitch angle of the lean vehicle 1 relative to the horizontal direction. The pitch angle corresponds to an angle that represents the vertical tilt of the body of the lean vehicle 1. Therefore, the pitch angle of the lean vehicle 1 relative to the horizontal direction corresponds to an angle that indicates how much the body of the lean vehicle 1 has rotated relative to the horizontal direction in the pitch direction, which is the rotation direction around the axis in the left-right direction of the vehicle. The inertial measurement unit 23 may be equipped with only a part of the three-axis gyro sensor and the three-direction acceleration sensor.

[0041]

[0026] Fig. 2 is a schematic diagram showing the overall configuration of a brake system 10. As shown in Fig. 2, the brake system 10 includes a brake operating unit 15 (specifically, a mechanism used as an operating unit for a front wheel braking unit 16), the front wheel braking unit 16, and a hydraulic control unit 18. The hydraulic control unit 18 includes a base body 18a. A master cylinder port 18b and a wheel cylinder port 18c are formed in the base body 18a.

[0042]

[0027] A brake operating unit 15 (specifically, a mechanism used as an operating unit for a front wheel brake unit 16) is connected to the master cylinder port 18b via a fluid pipe 31. The brake operating unit 15 includes a brake lever 15a, a master cylinder 15b, and a reservoir 15c. Master cylinder

[0043] Master cylinder port 18b has a piston portion (not shown) that moves in conjunction with the rider's operation of brake lever 15a, and is connected to master cylinder port 18b via fluid pipe 31. In other words, master cylinder port 18b is connected to fluid pipe 31 that communicates with master cylinder 15b. Reservoir 15c is attached to master cylinder 15b and stores brake fluid to be supplied to master cylinder 15b.

[0044]

[0028] The front wheel braking unit 16 is connected to the wheel cylinder port 18c via a fluid pipe 32. The front wheel braking unit 16 includes a wheel cylinder 16a and a rotor 16b. The wheel cylinder 16a is attached to the lower end of the front fork 12d. Wheel cylinder

[0045] The rotor 16b is provided with a piston portion (not shown) that moves in conjunction with the pressure of the fluid pipe 32, and is connected to the wheel cylinder port 18c via the fluid pipe 32. In other words, the fluid pipe 32 that communicates with the wheel cylinder 16a is connected to the wheel cylinder port 18c. The rotor 16b is held by the front wheel 13 and rotates together with the front wheel 13. As the piston portion of the wheel cylinder 16a moves, a brake pad (not shown) is pressed against the rotor 16b, thereby braking the front wheel 13.

[0046]

[0029] The base body 18a has a main flow path 41 and a sub-flow path 42 formed as internal flow paths through which brake fluid flows. The main flow path 41 is formed to connect the master cylinder port 18b and the wheel cylinder port 18c. In other words, the master cylinder 15b and the wheel cylinder 16a are connected by the fluid pipe 31, the main flow path 41, and the fluid pipe 32. The sub-flow path 42 is a flow path for releasing the brake fluid from the wheel cylinder 16a to the master cylinder 15b. The base body 18a may be formed from a single member or multiple members. Furthermore, when the base body 18a is formed from multiple members, each component may be provided separately in a different member.

[0047]

[0030] The main flow path 41 is provided with an inlet valve (EV) 51. The sub-flow path 42 bypasses the main flow path 41 between the wheel cylinder port 18c side and the master cylinder port 18b side of the inlet valve 51. The sub-flow path 42 is provided with a release valve (AV) 52 and an accumulator 53, in this order from the upstream side (i.e., the wheel cylinder port 18c side).

[0048]

[0031] The inlet valve 51 is, for example, a solenoid valve that opens when de-energized and closes when energized. The release valve 52 is, for example, a solenoid valve that closes when de-energized and opens when energized.

[0049]

[0032] The hydraulic control unit 18 also includes a hydraulic pressure sensor 24 that detects the pressure of the brake fluid in the wheel cylinder 16a. The hydraulic pressure sensor 24 is attached to the base 18a. For example, the hydraulic pressure sensor 24 is connected to a portion of the main flow path 41 that is closer to the wheel cylinder port 18c than the inlet valve 51 (in the example of FIG. 2, the portion of the main flow path 41 to which the upstream end of the sub-flow path 42 is connected).

[0050]

[0033] The hydraulic control unit 18 also includes a control device 60. The operation of the on valve 51 and the release valve 52 of the hydraulic control unit 18 is controlled by the control device 60. This controls the braking force acting on the front wheels 13.

[0051]

[0034] For example, in a normal state (i.e., a state in which slip control or lift-up control, which will be described later, is not being executed), the control device 60 opens the inlet valve 51 and closes the release valve 52. When the brake lever 15a is operated in this state, the piston (not shown) of the master cylinder 15b is pressed, increasing the pressure of the brake fluid in the wheel cylinder 16a, and the brake pad (not shown) is pressed against the rotor 16b, generating a braking force on the front wheel 13.

[0052]

[0035] Figure 3 is a block diagram showing an example of the functional configuration of the control device 60. For example, part or all of the control device 60 is configured with a microcomputer, a microprocessor unit, etc. Furthermore, for example, part or all of the control device 60 may be configured with an updatable component such as firmware, or may be a program module executed by a command from a CPU, etc. The control device 60 may be, for example, one unit, or may be divided into multiple units.

[0053]

[0036] As shown in Fig. 3, the control device 60 includes, for example, an acquisition unit 61 and an execution unit 62. The control device 60 also communicates with each device of the lean vehicle 1.

[0054]

[0037] The acquisition unit 61 acquires information from each device of the lean vehicle 1 and outputs it to the execution unit 62. For example, the acquisition unit 61 acquires information from the input device 21, the front wheel speed sensor 22, the inertial measurement unit 23, and the hydraulic pressure sensor 24. In this specification, the acquisition of information may include the extraction or generation of information (for example, calculation), etc.

[0055]

[0038] The execution unit 62 executes various controls by controlling the operation of each device of the lean vehicle 1. For example, the execution unit 62 controls the operation of the inlet valve 51 and the outlet valve 52 of the hydraulic control unit 18.

[0056]

[0039] <Operation of the rider assistance system> With reference to Figures 4 to 7, the operation of the rider assistance system 100 according to the embodiment of the present invention will be described.

[0057] As described above, the execution unit 62 of the control device 60 controls the operation of the on valve 51 and the release valve 52 of the hydraulic control unit 18. This controls the pressure of the brake fluid in the wheel cylinder 16 a, and thereby the braking force acting on the front wheel 13. Hereinafter, the control of the pressure of the brake fluid in the wheel cylinder 16 a will be collectively referred to as pressure control.

[0058] Here, in pressure control, the execution unit 62 can execute a pressure reducing operation to reduce the pressure of the brake fluid in the wheel cylinder 16 a. The pressure reducing operation is performed by releasing the brake fluid from the wheel cylinder 16 a to the accumulator 53. Specifically, in the pressure reducing operation, the execution unit 62 closes the inlet valve 51 and opens the release valve 52. As a result, the brake fluid flows from the wheel cylinder 16 a to the accumulator 53, the pressure of the brake fluid in the wheel cylinder 16 a decreases, and the braking force acting on the front wheel 13 decreases. Such a pressure reducing operation is performed when the rider of the lean vehicle 1 is braking using the brake operating unit 15, and is performed to stabilize the vehicle body posture.

[0059]

[0042] For example, the execution unit 62 can execute slip control as pressure control to suppress slip of the wheels (front wheels 13 in the above example) of the lean vehicle 1. In the slip control, the execution unit 62 executes a pressure reducing operation when it is estimated that the front wheels 13 are locking due to braking force acting on the front wheels 13. By performing such a pressure reducing operation, it is possible to stabilize the vehicle body posture by suppressing slip of the front wheels 13.

[0060] For example, when the degree of slip of the front wheel 13 exceeds a threshold value, the execution unit 62 estimates that the front wheel 13 is locked and performs a pressure reduction operation. The degree of wheel slip is an index showing the degree to which the wheel is slipping on the road surface, and can be expressed, for example, by a value obtained by dividing the difference between the vehicle speed of the lean vehicle 1 and the wheel speed of the wheel by the vehicle speed. The threshold value of the degree of slip is set to a value that can appropriately estimate whether the front wheel 13 is locked. Note that the acquisition unit 61 can acquire the degree of slip of the front wheel 13 by, for example, acquiring the vehicle speed of the lean vehicle 1 by a known method using the detection result of the front wheel speed sensor 22.

[0061]

[0044] Furthermore, the execution unit 62 can execute, for example, as pressure control, lift-up control to suppress lift-up of the rear wheels 14 of the lean vehicle 1. Note that lift-up of the rear wheels 14 refers to a state in which the front wheels 13 of the lean vehicle 1 are on the ground and the rear wheels 14 are off the ground, and occurs, for example, when the front wheels 13 are suddenly braked (that is, brakes accompanied by a sudden change in braking force) when the vehicle speed is relatively high. In the lift-up control, the execution unit 62 executes a pressure reducing operation when it is estimated that lift-up of the rear wheels 14 is occurring. By performing such a pressure reducing operation, it is possible to stabilize the vehicle body posture by suppressing lift-up of the rear wheels 14.

[0062] For example, when the occurrence of lift-up of the rear wheels 14 or the duration of the state in which there is a possibility of lift-up of the rear wheels 14 exceeds a minimum value, the execution unit 62 estimates that lift-up of the rear wheels 14 has occurred and performs a pressure reduction operation. For example, the execution unit 62 can determine whether lift-up of the rear wheels 14 has occurred or whether a state in which there is a possibility of lift-up of the rear wheels 14 has occurred based on information about the pitch angle of the lean vehicle 1 detected by the inertial measurement unit 23. The execution unit 62 can specify the duration of the above-mentioned state by repeatedly performing this determination. The minimum value of the above-mentioned duration is set to, for example, a value that can appropriately estimate whether lift-up of the rear wheels 14 has occurred.

[0063]

[0046] As will be described later, the information used to determine whether the rear wheel 14 has lifted up or whether a state in which the rear wheel 14 may lift up has occurred is not limited to the above example.

[0064]

[0047] For example, when the deceleration of the lean vehicle 1 exceeds a threshold value, the execution unit 62 estimates that lift-up of the rear wheels 14 has occurred and performs a pressure reduction operation. For example, the execution unit 62 can identify the deceleration of the lean vehicle 1 by calculating the time change rate of the vehicle speed of the lean vehicle 1. The threshold value of the deceleration is set to a value that can appropriately estimate whether lift-up of the rear wheels 14 has occurred.

[0065]

[0048] Unlike the hydraulic control unit 18 according to this embodiment, the hydraulic control unit may be provided with a pump that discharges brake fluid accumulated in the accumulator 53 from the accumulator 53. In this case, while the brake operation is continuing, the pump can discharge the brake fluid accumulated in the accumulator 53 by reducing the pressure.

[0066]

[0049] On the other hand, the hydraulic control unit 18 according to this embodiment is not provided with the pump. Therefore, the brake fluid accumulated in the accumulator 53 cannot be discharged until the brake operation is released, and the amount of brake fluid accumulated in the accumulator 53 increases each time a pressure-reducing operation is performed. This can lead to a situation where the accumulator 53 becomes full of brake fluid and pressure-reducing operation cannot be performed. Therefore, one possible measure to resolve this situation is to make it difficult to initiate the pressure-reducing operation. However, simply making it difficult to initiate the pressure-reducing operation may excessively suppress the pressure-reducing operation, which may reduce the stability of the vehicle posture.

[0067] Therefore, in this embodiment, the execution unit 62 of the control device 60 is devised to perform pressure control processing, thereby preventing the accumulator 53 from becoming filled with brake fluid and appropriately stabilizing the vehicle body posture, even when the hydraulic control unit 18 is not provided with a pump. Below, a first example, a second example, and a third example will be described in order as examples of processing performed by the control device 60.

[0068]

[0051] Fig. 4 is a flowchart showing a first example of the flow of processing performed by the control device 60. Step S101 in Fig. 4 corresponds to the start of the processing flow shown in Fig. 4.

[0069]

[0052] The processing flow in Fig. 4 is an example of processing related to slip control among pressure controls. Here, the execution unit 62 can switch the slip control mode among multiple modes. Specifically, the rider can select a mode by operating the input device 21, and the execution unit 62 switches the slip control mode to the mode selected by the rider.

[0070]

[0053] For ease of understanding, the following describes an example in which two slip control modes, a normal mode and an off-road mode, are provided. However, as will be described later, three or more slip control modes may be provided.

[0071]

[0054] The normal mode is a mode in which slip control suitable for driving on paved roads, for example. On the other hand, the off-road mode is a mode in which slip control suitable for driving on unpaved roads, i.e., off-road, is a mode in which slip control is performed. The processing flow of FIG. 4 is an example of processing related to slip control, particularly processing that is started when the slip control mode is set to off-road mode. Note that when the slip control mode is set to normal mode, steps S102 and S103, described below, can be omitted from the processing flow of FIG. 4.

[0072]

[0055] When the processing flow shown in FIG. 4 starts, in step S102, the acquisition unit 61 acquires remaining capacity information of the accumulator 53.

[0073]

[0056] The remaining capacity information of the accumulator 53 is information related to the remaining capacity of the accumulator 53. The remaining capacity of the accumulator 53 means the current capacity of the accumulator 53 to store brake fluid (i.e., an index of how much brake fluid the accumulator 53 can store in the future). For example, the remaining capacity of the accumulator 53 is the free capacity of the accumulator 53 at the current time (i.e., the remaining capacity).

[0074]

[0057] When the rider releases the brake operation, brake fluid is discharged from the accumulator 53 due to the differential pressure, and the available capacity of the accumulator 53 reaches its maximum capacity. Here, the maximum capacity of the accumulator 53 is pre-stored, for example, in a memory element of the control device 60. Then, when the brake operation is released, the acquisition unit 61 acquires, as remaining capacity information, information indicating that the available capacity of the accumulator 53 has reached its maximum capacity. Note that the acquisition unit 61 can determine whether the brake operation has been released, for example, based on the detection result of the hydraulic pressure sensor 24.

[0075]

[0058] After the brake operation is started, brake fluid accumulates in the accumulator 53 each time a pressure reduction operation is performed, and the available capacity of the accumulator 53 decreases. Here, the amount of decrease in the available capacity of the accumulator 53 resulting from one pressure reduction operation is stored in advance in, for example, a storage element of the control device 60. Then, the acquisition unit 61 subtracts the amount of decrease from the maximum capacity of the accumulator 53 each time a pressure reduction operation is performed, and acquires information indicating that the available capacity of the accumulator 53 has reached the value obtained in this way as remaining capacity information.

[0076]

[0059] As will be described later, the method of obtaining remaining capacity information is not limited to the above example.

[0077]

[0060] Next, in step S103, the execution unit 62 sets a threshold value for the degree of slip of the front wheels 13. As described above, in slip control, the execution unit 62 executes a pressure reduction operation when the degree of slip of the front wheels 13 exceeds the threshold value. In step S103, this threshold value is set.

[0078]

[0061] Figure 5 is a graph showing an example of the relationship between the remaining capacity RC and the threshold value TH. In Figure 5, the horizontal axis represents the remaining capacity RC, and the vertical axis represents the threshold value TH. In Figure 5, the solid line L1 represents the threshold value TH used in the off-road mode, and the dashed line L2 represents the threshold value TH used in the normal mode.

[0079]

[0062] As shown in Figure 5, in off-road mode, the minus value TH is larger than in normal mode. Generally, the more difficult it is to perform the pressure reduction operation, the less vehicle stability will be sufficiently improved. However, the longer the time the brake fluid pressure in the wheel cylinder 16a is high, and the shorter the braking distance will be. Therefore, the larger the minus value TH, the shorter the braking distance will be. Here, when riding in off-road mode, the rider places more importance on shortening the braking distance than on sufficiently improving vehicle stability. Therefore, by making the minus value TH in off-road mode larger than the minus value TH in normal mode, slip control suitable for off-road mode can be achieved.

[0080]

[0063] Here, as shown by the two-dot chain line L2 in Fig. 5, in the normal mode, the threshold value TH is constant regardless of the remaining capacity RC. Therefore, when the slip control mode is set to the normal mode, the execution unit 62 uses a constant value as the threshold value TH regardless of the remaining capacity RC.

[0081]

[0064] On the other hand, as shown by the solid line L1 in Fig. 5, in off-road mode, the lower the remaining capacity RC, the larger the min value TH. Therefore, when the slip control mode is set to off-road mode, the execution unit 62 changes the min value TH according to the remaining capacity information. Specifically, in the above case, when the remaining capacity information indicates that the remaining capacity RC is low, the execution unit 62 increases the min value TH compared to when the remaining capacity information indicates that the remaining capacity RC is high. For example, the execution unit 62 increases the min value TH as the remaining capacity RC decreases.

[0082]

[0065] As described above, in the first example, when the slip control mode is set to the off-road mode, the execution unit 62 increases the threshold value TH of the slip degree of the front wheels 13 when the remaining capacity information indicates that the remaining capacity RC is low, compared to when the remaining capacity information indicates that the remaining capacity RC is high. This makes it less likely that a pressure reduction operation will be performed. In other words, when the remaining capacity information indicates that the remaining capacity RC is low, the execution unit 62 changes the threshold value TH of the slip degree of the front wheels 13 so that a pressure reduction operation will be less likely to be performed, compared to when the remaining capacity information indicates that the remaining capacity RC is high. The operation of setting the threshold value TH for the degree of slip of the front wheels 13 in this manner is an example of an intervention suppression operation that makes it more difficult to initiate a pressure reduction operation when the remaining capacity information indicates that the remaining capacity RC is low, compared to when the remaining capacity information indicates that the remaining capacity RC is high.

[0083]

[0066] Next, in step S104, the execution unit 62 determines whether the degree of slip of the front wheel 13 has exceeded the threshold value TH. The determination in step S104 is made using the threshold value TH set in step S103.

[0067] If it is determined that the degree of slip of the front wheel 13 has not exceeded the threshold value TH (step S104 / NO), step S104 is repeated. On the other hand, if it is determined that the degree of slip of the front wheel 13 has exceeded the threshold value TH (step S104 / YES), the process proceeds to step S105.

[0084]

[0068] If the answer is YES in step S104, in step S105, the execution unit 62 performs a decompression operation and returns to step S102.

[0085]

[0069] In step S105, the execution unit 62 continues the pressure reduction operation for a predetermined time, for example (i.e., the inlet valve 51 is kept closed and the release valve 52 is kept open). Then, the execution unit 62 ends the pressure reduction operation when the predetermined time has elapsed (for example, after it is determined that the stability of the vehicle body has been ensured, the inlet valve 51 is gradually opened and the release valve 52 is closed).

[0086]

[0070] If a pressure reducing operation is performed while the brake operation is continuing, in step S102 after step S105, information indicating that the remaining capacity RC (e.g., free capacity) of the accumulator 53 is a smaller value than in the previous step S102 is acquired as remaining capacity information. Therefore, in step S103 after step S102, the minimum value TH of the degree of slip of the front wheels 13 is set to a larger value than in the previous step S103. In this way, each time a pressure reducing operation is performed, the minimum value TH becomes larger, making it more difficult to perform a pressure reducing operation.

[0087]

[0071] As described above, in the first example of Fig. 4, the execution unit 62 executes a pressure reduction operation when the degree of slip exceeds the threshold value TH in slip control. When the remaining capacity information indicates that the remaining capacity RC is low, the execution unit 62 executes an intervention suppression operation to change the threshold value TH so that the pressure reduction operation is less likely to be performed compared to when the remaining capacity information indicates that the remaining capacity RC is high. As described above, the intervention suppression operation is an operation that makes it less likely to intervene in the pressure reduction operation when the remaining capacity information of the accumulator 53 indicates that the remaining capacity RC of the accumulator 53 is low compared to when the remaining capacity information indicates that the remaining capacity RC is high.

[0088]

[0072] In the first example of Fig. 4, the above-mentioned intervention suppression operation is performed to prevent the accumulator 53 from becoming full of brake fluid. Furthermore, the above-mentioned intervention suppression operation makes it more difficult for the pressure reduction operation to intervene the lower the remaining capacity RC. Therefore, when the remaining capacity RC is high, excessive suppression of the pressure reduction operation can be prevented, and the vehicle body posture can be appropriately stabilized. Therefore, in slip control, the accumulator 53 can be prevented from becoming full of brake fluid, and the vehicle body posture can be appropriately stabilized.

[0089]

[0073] In the first example of Fig. 4, by executing the intervention suppression operation, when the remaining capacity RC of the accumulator 53 is reduced due to the pressure reduction operation by the slip control, the pressure reduction operation does not intervene and the brake fluid pressure in the wheel cylinder 16a is increased for a longer period of time, thereby shortening the braking distance of the lean vehicle 1. Therefore, the slip control can shorten the braking distance while ensuring the stabilization of the vehicle body posture through the pressure reduction operation. As a result, for example, when driving off-road, where shortening the braking distance is important, it is possible to appropriately shorten the braking distance. Therefore, the slip control can appropriately control the behavior of the lean vehicle 1.

[0090]

[0074] In particular, the execution unit 62 executes the intervention suppression operation in the off-road mode among the multiple modes. As a result, in the slip control, vehicle stability is maintained in modes other than the off-road mode (normal mode in the above example), while in the off-road mode where shortening the braking distance is important, the braking distance is appropriately shortened in consideration of the remaining braking capacity RC.

[0091]

[0075] In the above, an example has been described in which, when the remaining capacity information indicates that the remaining capacity RC is low, the operation of changing the threshold value TH of the slippage in the slip control so that the pressure reduction operation is less likely to be performed is executed as the intervention suppression operation, compared to when the remaining capacity information indicates that the remaining capacity RC is high. However, the execution unit 62 may execute an operation different from the above as the intervention suppression operation in the slip control that executes the pressure reduction operation when the degree of slippage exceeds the threshold value TH.

[0092] For example, when the remaining capacity information indicates that the remaining capacity RC is low, the execution unit 62 may execute an intervention suppression operation to delay the start timing of the pressure reduction operation, which is based on (specifically, the starting point) the point at which the degree of slip exceeds the minimum value TH, compared to when the remaining capacity information indicates that the remaining capacity RC is high. By executing such an intervention suppression operation, it is possible to prevent the accumulator 53 from becoming full of brake fluid, as in the above example. Furthermore, the above intervention suppression operation makes it more difficult to initiate the pressure reduction operation as the remaining capacity RC decreases. Therefore, it is possible to prevent the pressure reduction operation from being excessively suppressed when the remaining capacity RC is high, and to appropriately stabilize the vehicle body posture. Therefore, in slip control, it is possible to appropriately stabilize the vehicle body posture while preventing the accumulator 53 from becoming full of brake fluid.

[0093]

[0077] As in the above example, by executing the intervention suppression operation, when the remaining capacity RC of the accumulator 53 is low due to the pressure reduction operation by slip control, the brake fluid pressure in the wheel cylinder 16a can be increased for a longer period of time without the pressure reduction operation being performed, thereby shortening the braking distance of the lean vehicle 1. Therefore, slip control can shorten the braking distance while ensuring stabilization of the vehicle body posture through the pressure reduction operation. This makes it possible to appropriately shorten the braking distance, for example, when driving off-road, where shortening the braking distance is important. Therefore, slip control can appropriately control the behavior of the lean vehicle 1.

[0094]

[0078] The intervention suppression operation that changes the start timing as described above is also executed, for example, when the slip control mode is set to off-road mode. When the slip control mode is set to off-road mode, the execution unit 62, for example, sets a constant value for the min value TH regardless of the remaining capacity RC, and delays the start timing as the remaining capacity RC decreases. As a result, the time difference between the point at which the degree of slip exceeds the min value TH and the timing at which the depressurization operation starts becomes longer as the remaining capacity RC decreases. Note that when the slip control mode is set to off-road mode, the execution unit 62 may, for example, increase the min value TH as the remaining capacity RC decreases, and delay the start timing as the remaining capacity RC decreases.

[0095]

[0079] Fig. 6 is a flowchart showing a second example of the flow of processing performed by the control device 60. Step S201 in Fig. 6 corresponds to the start of the processing flow shown in Fig. 6.

[0096]

[0080] The processing flow in Fig. 6 is an example of processing related to lift-up control among pressure controls. Here, the execution unit 62 can switch the lift-up control mode between multiple modes, similar to the above-mentioned slip control modes. Specifically, the rider can select a mode by operating the input device 21, and the execution unit 62 switches the lift-up control mode to the mode selected by the rider.

[0081] For ease of understanding, an example will be described below in which two modes of lift-up control, a normal mode and an off-road mode, are provided, similar to the above-mentioned slip control modes. However, as will be described later, three or more modes may be provided as lift-up control modes.

[0097]

[0082] The normal mode is a mode in which lift-up control suitable for driving on paved roads, for example. On the other hand, the off-road mode is a mode in which lift-up control suitable for driving on unpaved roads, i.e., off-road, is performed. The processing flow in Fig. 6 is an example of processing related to lift-up control, which is started particularly when the lift-up control mode is set to the off-road mode. Note that when the lift-up control mode is set to the normal mode, steps S202 and S203, which will be described later, can be omitted from the processing flow in Fig. 6.

[0098]

[0083] When the processing flow shown in Fig. 6 starts, in step S202, the acquisition unit 61 acquires remaining capacity information of the accumulator 53. The processing in step S202 is the same as the processing in step S202 in Fig. 4 described above.

[0099]

[0084] Next, in step S203, the execution unit 62 sets a minimum value for the duration of the occurrence of lift-up of the rear wheels 14 or the state in which there is a possibility of lift-up of the rear wheels 14. As described above, in lift-up control, the execution unit 62 executes a pressure reduction operation if the duration exceeds the minimum value. In step S203, this minimum value is set.

[0100]

[0085] The relationship between the duration value and the remaining capacity RC is the same as the relationship between the value TH and the remaining capacity RC in Figure 5 described above. Specifically, in off-road mode, the duration value is larger than in normal mode. In normal mode, the duration value is constant regardless of the remaining capacity RC. Therefore, when the lift-up control mode is set to normal mode, the execution unit 62 uses a constant value as the duration value regardless of the remaining capacity RC. On the other hand, in off-road mode, the duration value increases as the remaining capacity RC decreases. Therefore, when the lift-up control mode is set to off-road mode, the execution unit 62 increases the duration value when the remaining capacity information indicates that the remaining capacity RC is low compared to when the remaining capacity information indicates that the remaining capacity RC is high. This makes it difficult for the pressure reduction operation to be performed. Therefore, the operation of setting the minimum value of the duration as described above corresponds to an example of an intervention suppression operation.

[0101]

[0086] Next, in step S204, the execution unit 62 determines whether or not the occurrence of lift-up of the rear wheel 14 or the duration of the state in which there is a possibility of lift-up of the rear wheel 14 exceeds a threshold value. The determination in step S204 is made using the threshold value of the duration set in step S203.

[0102]

[0087] If it is determined that the duration does not exceed the minimum value (step S204 / NO), step S204 is repeated. On the other hand, if it is determined that the duration exceeds the minimum value (step S204 / YES), the process proceeds to step S205.

[0103]

[0088] If the answer is YES in step S204, in step S205, the execution unit 62 performs a decompression operation and returns to step S202.

[0104]

[0089] If a pressure reducing operation is performed while the brake operation is continuing, in step S202 after step S205, information indicating that the remaining capacity RC (e.g., free capacity) of the accumulator 53 is a smaller value than in the previous step S202 is acquired as remaining capacity information. Therefore, in step S203 after step S202, the minimum value of the duration is set to a larger value than in the previous step S203. In this way, each time a pressure reducing operation is performed, the minimum value of the duration increases, making it more difficult to perform the pressure reducing operation.

[0105] As described above, in the second example of Fig. 6, the execution unit 62 executes a pressure reduction operation when the occurrence of lift-up of the rear wheels 14 or the duration of a state in which there is a possibility of lift-up of the rear wheels 14 exceeding the minimum value in the lift-up control. When the remaining capacity information indicates that the remaining capacity RC is low, the execution unit 62 executes an intervention suppression operation in which the minimum value of the duration is changed so that the pressure reduction operation is less likely to be executed compared to when the remaining capacity information indicates that the remaining capacity RC is high.

[0106]

[0091] In the second example of Fig. 6, the above-mentioned intervention suppression operation is performed to prevent the accumulator 53 from becoming full of brake fluid. Furthermore, the above-mentioned intervention suppression operation makes it more difficult for the pressure reduction operation to intervene the lower the remaining capacity RC. Therefore, when the remaining capacity RC is high, excessive suppression of the pressure reduction operation can be prevented, and the vehicle body posture can be appropriately stabilized. Therefore, in the lift-up control, the accumulator 53 can be prevented from becoming full of brake fluid, and the vehicle body posture can be appropriately stabilized.

[0107]

[0092] In the second example of Fig. 6, by executing the intervention suppression operation, when the remaining capacity RC of the accumulator 53 is reduced due to the pressure reduction operation by the lift-up control, the pressure reduction operation does not intervene and the brake fluid pressure in the wheel cylinder 16a is increased for a longer period of time, thereby shortening the braking distance of the lean vehicle 1. Therefore, the lift-up control can shorten the braking distance while ensuring stabilization of the vehicle body posture through the pressure reduction operation. As a result, it is possible to appropriately shorten the braking distance, for example, when driving off-road, where shortening the braking distance is important. Therefore, the lift-up control can appropriately control the behavior of the lean vehicle 1.

[0108]

[0093] In particular, the execution unit 62 executes the intervention suppression operation in the off-road mode among the multiple modes. As a result, in the lift-up control, vehicle stability is maintained in modes other than the off-road mode (normal mode in the above example), while the braking distance is appropriately shortened in the off-road mode, which places importance on shortening the braking distance, taking into account the remaining braking capacity RC.

[0109]

[0094] In the above, an example has been described in which, when the remaining capacity information indicates that the remaining capacity RC is low, the operation of changing the minimum value of the duration in the lift-up control so that the pressure reduction operation is less likely to be performed is executed as the intervention suppression operation compared to when the remaining capacity information indicates that the remaining capacity RC is high. However, the execution unit 62 may execute an operation different from the above as the intervention suppression operation in the lift-up control that executes the pressure reduction operation when the duration exceeds the minimum value.

[0110] For example, when the remaining capacity information indicates that the remaining capacity RC is low, the execution unit 62 may execute an intervention suppression operation to delay the start timing of the pressure reduction operation, using the point in time when the duration exceeds the minimum value as a reference (specifically, the starting point), compared to when the remaining capacity information indicates that the remaining capacity RC is high. By executing such an intervention suppression operation, it is possible to prevent the accumulator 53 from becoming full of brake fluid, as in the above example. Furthermore, the above intervention suppression operation makes it more difficult to initiate the pressure reduction operation as the remaining capacity RC decreases. Therefore, it is possible to prevent the pressure reduction operation from being excessively suppressed when the remaining capacity RC is high, and to appropriately stabilize the vehicle body posture. Therefore, in the lift-up control, it is possible to appropriately stabilize the vehicle body posture while preventing the accumulator 53 from becoming full of brake fluid.

[0111]

[0096] Furthermore, by executing the intervention suppression operation, similarly to the above example, when the remaining capacity RC of the accumulator 53 is reduced due to the pressure reduction operation by the lift-up control, the brake fluid pressure in the wheel cylinder 16a can be increased for a longer period of time without the pressure reduction operation being performed, thereby shortening the braking distance of the lean vehicle 1. Therefore, the lift-up control can shorten the braking distance while ensuring stabilization of the vehicle body posture through the pressure reduction operation. As a result, it is possible to appropriately shorten the braking distance, for example, when driving off-road, where shortening the braking distance is important. Therefore, the lift-up control can appropriately control the behavior of the lean vehicle 1.

[0112]

[0097] The intervention suppression operation that changes the start timing as described above is also executed, for example, when the lift-up control mode is set to off-road mode. When the lift-up control mode is set to off-road mode, the execution unit 62, for example, sets a constant value for the duration minimum regardless of the remaining capacity RC, and delays the start timing as the remaining capacity RC decreases. As a result, the time difference between the time when the duration exceeds the minimum value and the time when the pressure reduction operation starts becomes longer as the remaining capacity RC decreases. Note that when the lift-up control mode is set to off-road mode, the execution unit 62 may, for example, increase the duration minimum as the remaining capacity RC decreases, and delay the start timing as the remaining capacity RC decreases.

[0113]

[0098] Fig. 7 is a flowchart showing a third example of the flow of processing performed by the control device 60. Step S301 in Fig. 7 corresponds to the start of the processing flow shown in Fig. 7.

[0114]

[0099] The process flow of Fig. 7, like the process flow of Fig. 6 described above, is an example of a process related to lift-up control among pressure controls, and in particular, is an example of a process that is started when the lift-up control mode is set to the off-road mode. Note that when the lift-up control mode is set to the normal mode, Steps S302 and S303, which will be described later, may be omitted from the process flow of Fig. 7.

[0115]

[0100] When the processing flow shown in Fig. 7 starts, in step S302, the acquisition unit 61 acquires remaining capacity information of the accumulator 53. The processing in step S302 is the same as the processing in step S302 in Fig. 4 described above.

[0116]

[0101] Next, in step S303, the execution unit 62 sets a minimum value for the deceleration of the lean vehicle 1. As described above, in the lift-up control, the execution unit 62 executes a pressure reduction operation when the deceleration of the lean vehicle 1 exceeds the minimum value. In step S303, this minimum value is set.

[0117]

[0102] The relationship between the deceleration threshold and the remaining capacity RC is the same as the relationship between the threshold TH and the remaining capacity RC in Figure 5 described above. Specifically, in off-road mode, the deceleration threshold is larger than in normal mode. Also, in normal mode, the deceleration threshold is constant regardless of the remaining capacity RC. Therefore, when the lift-up control mode is set to normal mode, the execution unit 62 uses a constant value as the deceleration threshold regardless of the remaining capacity RC. On the other hand, in off-road mode, the deceleration threshold increases as the remaining capacity RC decreases. Therefore, when the lift-up control mode is set to off-road mode, the execution unit 62 increases the deceleration threshold when the remaining capacity information indicates that the remaining capacity RC is low compared to when the remaining capacity information indicates that the remaining capacity RC is high. Therefore, the operation of setting the deceleration threshold as described above corresponds to an example of an intervention suppression operation.

[0118]

[0103] Next, in step S304, the execution unit 62 determines whether the deceleration of the lean vehicle 1 exceeds the minimum value. The determination in step S304 is made using the minimum value of the deceleration set in step S303.

[0119]

[0104] If it is determined that the deceleration of the lean vehicle 1 does not exceed the minimum value (step S304 / NO), step S304 is repeated. On the other hand, if it is determined that the deceleration of the lean vehicle 1 exceeds the minimum value (step S304 / YES), proceed to step S305.

[0120]

[0105] If the answer is YES in step S304, in step S305, the execution unit 62 performs the decompression operation and returns to step S302.

[0121]

[0106] If a pressure reducing operation is performed while the brake operation is continuing, in step S302 after step S305, information indicating that the remaining capacity RC (e.g., free capacity) of the accumulator 53 is a smaller value than in the previous step S302 is acquired as remaining capacity information. Therefore, in step S303 after step S302, the minimum value of the deceleration is set to a larger value than in the previous step S303. In this way, each time a pressure reducing operation is performed, the minimum value of the deceleration increases, making it more difficult to perform the pressure reducing operation.

[0122] As described above, in the third example of Fig. 7, the execution unit 62 executes a pressure reduction operation when the deceleration of the lean vehicle 1 exceeds the minimum value during lift-up control. When the remaining capacity information indicates that the remaining capacity RC is low, the execution unit 62 executes an intervention suppression operation to change the minimum value of the deceleration so that the pressure reduction operation is less likely to be executed, compared to when the remaining capacity information indicates that the remaining capacity RC is high.

[0123]

[0108] In the third example of Fig. 7, the above-mentioned intervention suppression operation is performed, thereby preventing the accumulator 53 from becoming full of brake fluid. Furthermore, the above-mentioned intervention suppression operation makes it more difficult for the pressure reducing operation to intervene the lower the remaining capacity RC. Therefore, when the remaining capacity RC is high, excessive suppression of the pressure reducing operation can be prevented, and the vehicle body posture can be appropriately stabilized. Therefore, in lift-up control, the accumulator 53 can be prevented from becoming full of brake fluid, and the vehicle body posture can be appropriately stabilized.

[0124]

[0109] In the third example of FIG. 7, by executing the intervention suppression operation, when the remaining capacity RC of the accumulator 53 is reduced due to the pressure reduction operation by the lift-up control, the pressure reduction operation does not intervene and the brake fluid pressure in the wheel cylinder 16a is increased for a longer period of time, thereby shortening the braking distance of the lean vehicle 1. Therefore, the lift-up control can shorten the braking distance while ensuring stabilization of the vehicle body posture through the pressure reduction operation. As a result, it is possible to appropriately shorten the braking distance, for example, when driving off-road, where shortening the braking distance is important. Therefore, the lift-up control can appropriately control the behavior of the lean vehicle 1.

[0125]

[0110] In particular, the execution unit 62 executes the intervention suppression operation in the off-road mode among the multiple modes. As a result, in the lift-up control, vehicle stability is maintained in modes other than the off-road mode (normal mode in the above example), while the braking distance is appropriately shortened in the off-road mode, which places importance on shortening the braking distance, taking into account the remaining braking capacity RC.

[0126]

[0111] In the above, an example has been described in which, when the remaining capacity information indicates that the remaining capacity RC is low, the operation of changing the minimum value of the deceleration in the lift-up control so that the pressure reduction operation is less likely to be performed is executed as the intervention suppression operation compared to when the remaining capacity information indicates that the remaining capacity RC is high. However, the execution unit 62 may execute an operation different from the above as the intervention suppression operation in the lift-up control in which the pressure reduction operation is executed when the deceleration exceeds the minimum value.

[0127] For example, when the remaining capacity information indicates that the remaining capacity RC is low, the execution unit 62 may execute an intervention suppression operation to delay the start timing of the pressure reduction operation, which is based on (specifically, the starting point of) the point at which the deceleration exceeds the minimum value, compared to when the remaining capacity information indicates that the remaining capacity RC is high. By executing such an intervention suppression operation, it is possible to prevent the accumulator 53 from becoming full of brake fluid, as in the above example. Furthermore, the above intervention suppression operation makes it more difficult to initiate the pressure reduction operation as the remaining capacity RC decreases. Therefore, it is possible to prevent the pressure reduction operation from being excessively suppressed when the remaining capacity RC is high, and to appropriately stabilize the vehicle body posture. Therefore, in lift-up control, it is possible to appropriately stabilize the vehicle body posture while preventing the accumulator 53 from becoming full of brake fluid.

[0128]

[0113] Furthermore, by executing the above intervention suppression operation, as in the above example, when the remaining capacity RC of the accumulator 53 is reduced due to the pressure reduction operation by the lift-up control, the brake fluid pressure in the wheel cylinder 16a can be increased for a longer period of time without the pressure reduction operation being performed, thereby shortening the braking distance of the lean vehicle 1. Therefore, the lift-up control can shorten the braking distance while ensuring stabilization of the vehicle body posture through the pressure reduction operation. As a result, it is possible to appropriately shorten the braking distance, for example, when driving off-road, where shortening the braking distance is important. Therefore, the lift-up control can appropriately control the behavior of the lean vehicle 1.

[0129]

[0114] The intervention suppression operation that changes the start timing as described above is also executed, for example, when the lift-up control mode is set to off-road mode. When the lift-up control mode is set to off-road mode, the execution unit 62, for example, sets the deceleration minimum value to a fixed value regardless of the remaining capacity RC, and delays the start timing as the remaining capacity RC decreases. As a result, the time difference between the point at which the deceleration exceeds the minimum value and the timing at which the pressure reduction operation starts becomes longer as the remaining capacity RC decreases. Note that when the lift-up control mode is set to off-road mode, the execution unit 62 may, for example, increase the deceleration minimum value as the remaining capacity RC decreases, and delay the start timing as the remaining capacity RC decreases.

[0130]

[0115] The above describes an example of the process performed by the control device 60 with reference to Figs. 4 to 7. However, the process performed by the control device 60 may be a process obtained by adding modifications to the process example described above.

[0131]

[0116] For example, in the above, as the intervention suppression operation, the operation of changing the threshold value TH of the degree of slippage (see the first example), the operation of changing the start timing of the decompression operation based on the point when the degree of slippage exceeds the threshold value TH (see the first example), the operation of changing the threshold value of the duration (see the second example), the operation of changing the start timing of the decompression operation based on the point when the duration exceeds the threshold value (see the second example), the operation of changing the threshold value of the deceleration (see the third example), and the operation of changing the start timing of the decompression operation based on the point when the deceleration exceeds the threshold value (see the third example) have been described. However, the execution unit 62 may execute only any part of these operations as the intervention suppression operation, or may execute all of these operations as the intervention suppression operation.

[0132]

[0117] In the above example, the hydraulic pressure control unit 18 can control only the braking force acting on the front wheels 13 using the pressure of the brake fluid. However, the hydraulic pressure control unit 18 may be able to control both the braking force acting on the front wheels 13 and the braking force acting on the rear wheels 14 using the pressure of the brake fluid. For example, in the hydraulic pressure control unit 18, a brake fluid flow path and a solenoid valve for controlling the braking force acting on the rear wheels 14 may be added to the example of Fig. 2. In that case, the control device 60 can perform slip control to suppress slip of the rear wheels 14, and the above-mentioned slip control may be performed as such slip control.

[0133]

[0118] In the above example, the amount of decrease in the free capacity of the accumulator 53 resulting from one pressure reduction operation is stored in advance, and the remaining capacity information is acquired by subtracting the amount of decrease from the maximum capacity of the accumulator 53 each time a pressure reduction operation is performed. However, the method for acquiring the remaining capacity information is not limited to the above example. For example, the acquisition unit 61 may acquire the remaining capacity information using the detection result of a sensor that can detect the free capacity of the accumulator 53 or another physical quantity that can be substantially converted into the free capacity (for example, a sensor that detects the flow rate of brake fluid flowing into the accumulator 53, or a sensor that detects the deformation of the accumulator 53). Further, for example, the acquisition unit 61 may acquire remaining capacity information by estimating the flow rate of brake fluid flowing into the accumulator 53 based on the behavior of the wheel speed of the front wheels 13 or the amount of pressure reduction in the wheel cylinder 16 a.

[0134]

[0119] In the above example, for example, a case has been described in which it is determined whether or not the rear wheels 14 have lifted up or whether or not a state in which there is a possibility of the rear wheels 14 lifting up is occurring, based on information about the pitch angle of the lean vehicle 1 detected by the inertial measurement unit 23. However, the execution unit 62 may make the above determination based on other information. For example, if wheel speed sensors are provided for the rear wheels 14 in addition to the front wheels 13, the execution unit 62 may determine whether or not the rear wheels 14 have lifted up or whether or not a state in which there is a possibility of the rear wheels 14 lifting up is occurring, based on the difference between the wheel speeds of the front wheels 13 and the rear wheels 14. Furthermore, for example, if a stroke sensor is provided to detect the stroke amount of the suspension of the lean vehicle 1, the execution unit 62 may determine whether or not the rear wheels 14 have lifted up or whether or not a state in which there is a possibility of the rear wheels 14 being lifted up has occurred, based on the detection result of the stroke sensor.

[0135]

[0120] In the above example, the remaining capacity RC is used as a parameter to change the value TH of the slip degree in the slip control, the value TH of the duration in the lift-up control, or the value TH of the deceleration in the lift-up control. However, the execution unit 62 may adjust each of the above values ​​according to a parameter other than the remaining capacity RC.

[0136]

[0121] In the above example, for example, two modes, a normal mode and an off-road mode, are provided as pressure control (specifically, slip control or lift-up control). However, the number and names of the pressure control modes are not limited to those in the above example. For example, three or more pressure control modes may be provided. The names of the modes may be set appropriately depending on their intended use. In addition, in modes other than the off-road mode, the intervention suppression operation described above may be performed in the same way as in the off-road mode. Note that it may be impossible to switch the pressure control mode.

[0137]

[0122] In the above example, the execution unit 62 switches the pressure control mode based on manual setting information by the rider. The manual setting information is information related to manual setting by a lighter or a rider (for example, in the above example, information related to operation using the input device 21). However, the execution unit 62 may automatically switch the pressure control mode based on road surface information. For example, the acquisition unit 61 can acquire, as road surface information, information indicating whether the road surface on which the lean vehicle 1 is traveling is off-road, based on the detection result of the inertial measurement unit 23, map data, or the detection result of a suspension stroke sensor, etc. Then, when the execution unit 62 determines that the lean vehicle 1 is traveling off-road using such road surface information, it may automatically switch the pressure control mode to the off-road mode, and when it determines that the lean vehicle 1 is traveling on a paved road, it may automatically switch the pressure control mode to the normal mode. Furthermore, when the execution unit 62 automatically switches the pressure control mode, it may notify the rider that the pressure control mode has been switched. Note that the above notification can be made using various notification devices (for example, a display device or a sound output device provided on the lean vehicle 1).

[0138]

[0123] The execution unit 62 may execute a notification operation to notify the rider of the change in pressure control mode, without automatically switching the pressure control mode. For example, the execution unit 62 determines a mode suitable for the road surface (for example, off-road mode when the lean vehicle 1 is traveling off-road) based on road surface information, and suggests to the rider to switch to that mode in the notification operation. Then, when the rider performs an operation to permit the mode change using the input device 21 or the like, the execution unit 62 switches to that mode. The notification operation may be performed using various notification devices (for example, a display device or a sound output device provided on the lean vehicle 1).

[0139]

[0124] In addition, for example, in the above description, slip control and lift-up control have been described as examples of pressure control. However, the execution unit 62 may execute pressure control other than slip control and lift-up control as pressure control in which a depressurizing operation is executed, and may execute an intervention suppression operation in such pressure control.

[0140]

[0125] <Effects of the rider assistance system> The effects of the rider assistance system 1 according to the embodiment of the present invention will be described.

[0141]

[0126] The rider assistance system 100 includes a hydraulic control unit 18 that includes an accumulator 53 and controls the pressure of brake fluid in the wheel cylinder 16 a of the lean vehicle 1, and a control device 60 that includes an execution unit 62 that executes pressure control to execute a pressure reducing operation to reduce the pressure of the brake fluid in the wheel cylinder 16 a by releasing the brake fluid from the wheel cylinder 16 a to the accumulator 53. The hydraulic control unit 18 does not include a pump that discharges the brake fluid accumulated in the accumulator 53 from the accumulator 53. Then, in pressure control, when the remaining capacity information of the accumulator 53 indicates that the remaining capacity RC of the accumulator 53 is low, the execution unit 62 executes an intervention suppression operation that makes it more difficult to initiate a pressure reducing operation than when the remaining capacity information indicates that the remaining capacity RC is high. As a result, by executing the intervention suppression operation, it is possible to prevent the accumulator 53 from becoming full of brake fluid. Furthermore, the intervention suppression operation makes it more difficult to initiate a pressure reducing operation the lower the remaining capacity RC. Therefore, it is possible to prevent excessive suppression of the pressure reducing operation when the remaining capacity RC is high, and it is possible to appropriately stabilize the posture of the vehicle body. As described above, the rider assistance system 100 can appropriately stabilize the posture of the vehicle body while preventing the accumulator 53 from becoming full of brake fluid.

[0142]

[0127] According to the rider assistance system 100, when the remaining capacity RC of the accumulator 53 is reduced due to the pressure reduction operation, the brake fluid pressure in the wheel cylinder 16a can be increased for a longer period of time without the pressure reduction operation being performed, thereby shortening the braking distance of the lean vehicle 1. Therefore, the braking distance can be shortened while ensuring stability of the vehicle body posture through the pressure reduction operation. This makes it possible to appropriately shorten the braking distance, for example, when traveling off-road, where shortening the braking distance is important. Therefore, even when the hydraulic control unit 18 is not provided with a pump and the number of pressure reduction operations is limited, the behavior of the lean vehicle 1 can be appropriately controlled.

[0143]

[0128] Preferably, in the rider assistance system 100, the pressure control is slip control for suppressing slip of the wheels (in the above example, the front wheels 13) of the lean vehicle 1. As a result, in the slip control, the accumulator 53 can be prevented from becoming full of brake fluid, and the vehicle body posture can be appropriately stabilized.

[0144]

[0129] Preferably, in the rider assistance system 100, the execution unit 62 executes a pressure reduction operation in the slip control when the degree of slip exceeds a threshold value (in the above example, threshold value TH), and in the intervention suppression operation, the execution unit 62 changes the threshold value so that the pressure reduction operation is less likely to be executed when the remaining capacity information indicates that the remaining capacity RC is low compared to when the remaining capacity information indicates that the remaining capacity RC is high. This appropriately achieves the slip control to appropriately stabilize the vehicle posture while preventing the accumulator 53 from becoming full of brake fluid.

[0145] Preferably, in the rider assistance system 100, the execution unit 62 executes a pressure reduction operation in the slip control when the degree of slip exceeds a minimum value (in the above example, the minimum value TH), and in the intervention suppression operation, the execution unit 62 delays the start timing of the pressure reduction operation, which is based on the point in time when the degree of slip exceeds the minimum value, when the remaining capacity information indicates that the remaining capacity RC is low, compared to when the remaining capacity information indicates that the remaining capacity RC is high. This appropriately achieves, in the slip control, the vehicle posture being appropriately stabilized while preventing the accumulator 53 from becoming full of brake fluid.

[0146]

[0131] Preferably, in the rider assistance system 100, the pressure control is lift-up control for suppressing lift-up of the rear wheel 14 of the lean vehicle 1. As a result, in the lift-up control, the accumulator 53 can be prevented from becoming filled with brake fluid, and the vehicle body posture can be appropriately stabilized.

[0147]

[0132] Preferably, in the rider assistance system 100, the execution unit 62 executes a pressure reducing operation when lift-up occurs or the duration of a state where lift-up is possible exceeds a minimum value in the lift-up control, and the execution unit 62 changes the minimum value so that a pressure reducing operation is less likely to be executed when the remaining capacity information indicates that the remaining capacity RC is low compared to when the remaining capacity information indicates that the remaining capacity RC is high in the intervention suppression operation. This appropriately achieves the lift-up control to appropriately stabilize the vehicle posture while preventing the accumulator 53 from becoming full of brake fluid.

[0148]

[0133] Preferably, in the rider assistance system 100, the execution unit 62 executes a pressure reducing operation when lift-up occurs or the duration of a state where lift-up is possible exceeds a minimum value in the lift-up control, and the execution unit 62 delays the start timing of the pressure reducing operation, which is based on the point in time when the duration exceeds the minimum value, when the remaining capacity information indicates that the remaining capacity RC is low compared to when the remaining capacity information indicates that the remaining capacity RC is high in the intervention suppression operation. This appropriately achieves the lift-up control to appropriately stabilize the vehicle posture while preventing the accumulator 53 from becoming full of brake fluid.

[0134] Preferably, in the rider assistance system 100, the execution unit 62 executes a pressure reduction operation when the deceleration of the lean vehicle 1 exceeds a threshold value in the lift-up control, and the execution unit 62 changes the threshold value so that the pressure reduction operation is less likely to be executed when the remaining capacity information indicates that the remaining capacity RC is low compared to when the remaining capacity information indicates that the remaining capacity RC is high in the intervention suppression operation. This appropriately stabilizes the vehicle body posture while preventing the accumulator 53 from becoming full of brake fluid in the lift-up control.

[0149]

[0135] Preferably, in the rider assistance system 100, the execution unit 62 executes a pressure reducing operation when the deceleration of the lean vehicle 1 exceeds a minimum value in the lift-up control, and the execution unit 62 delays the start timing of the pressure reducing operation, based on the point in time when the deceleration exceeds the minimum value, when the remaining capacity information indicates that the remaining capacity RC is low, compared to when the remaining capacity information indicates that the remaining capacity RC is high, in the intervention suppression operation. This appropriately stabilizes the vehicle body posture while preventing the accumulator 53 from becoming full of brake fluid in the lift-up control.

[0150]

[0136] Preferably, in the rider assistance system 100, the execution unit 62 switches the pressure control mode between a plurality of modes, performs an intervention suppression operation in some of the plurality of modes, and does not perform an intervention suppression operation in other of the plurality of modes. As a result, in the other modes, vehicle stability is maintained, while in the above-mentioned some modes, shortening the braking distance is appropriately realized in consideration of the remaining braking capacity RC. Therefore, it is possible to switch between a mode that prioritizes vehicle stability and a mode that prioritizes shortening the braking distance.

[0151]

[0137] Preferably, in the rider assistance system 100, the multiple modes include an off-road mode, which is a mode for off-road driving (i.e., a mode for off-road driving), and the execution unit 62 executes intervention suppression operation in the off-road mode of the multiple modes. As a result, in modes other than the off-road mode (in the above example, the normal mode), vehicle stability is maintained, while in the off-road mode, the braking distance is appropriately shortened in consideration of the remaining braking capacity RC. Therefore, in the off-road mode, where shortening the braking distance is important, the braking distance is appropriately shortened.

[0152]

[0138] Preferably, in the rider assistance system 100, the execution unit 62 switches the pressure control mode based on manual setting information by the rider. This allows the pressure control mode to be switched in accordance with the rider's intention.

[0153]

[0139] Preferably, in the rider assistance system 100, the execution unit 62 automatically switches the pressure control mode based on road surface information. This reduces the effort required for the rider to switch modes and optimizes the pressure control mode according to the road surface on which the lean vehicle 1 is traveling.

[0154]

[0140] Preferably, in the rider assistance system 100, the execution unit 62 performs a notification operation to notify the rider of a change in pressure control mode. This allows, for example, the rider to be suggested a mode suitable for the road surface on which the lean vehicle 1 is traveling, and the rider to be prompted to switch to that mode.

[0155]

[0141] The present invention is not limited to the description of the embodiments. For example, only a part of the embodiments may be implemented.

[0156] [Explanation of symbols]

[0142] Lean vehicle, 10 Brake system, !1 Frame, !1a Head tube,

[0157] , lib top tube, 11c down tube, lid seat tube, lie stay, 12 turning part, 12a steering column, 12 handle stem, 12c handlebar, 12d front fork, 13 front wheel, 14 rear wheel, 15 brake operating part, 15a brake lever, 15b master cylinder, 15c reservoir, 16 front wheel braking part, 16a wheel cylinder, 16b rotor, 17 rear wheel braking part, 18 hydraulic control unit, 18a base, 18b master cylinder port, !8c wheel cylinder port, 2! Input device, 22 Front wheel speed sensor, 23 Inertial measurement unit, 24 Hydraulic pressure sensor, 31 Fluid pipe, 32 Fluid pipe, 41 Main flow path, 42 Secondary flow path, 51 Inlet valve, 52 Release valve, 53 Accumulator, 6〇 Control device, 61 Acquisition unit, 62 Execution unit, 100 Rider assistance system, L1 Solid line, L2 Dot-dash line, RC Remaining capacity, TH Min value.

Claims

[Document name] Scope of claims

1. A rider assistance system (100) for assisting a rider of a lean vehicle (1) in driving, comprising: a hydraulic control unit (18) for controlling the pressure of brake fluid in a wheel cylinder (16a) of the lean vehicle (1), including an accumulator (53); and a control device (60) including an execution unit (62) for executing pressure control to execute a pressure reducing operation for reducing the pressure of the brake fluid in the wheel cylinder (16a) by releasing the brake fluid from the wheel cylinder (16a) to the accumulator (53), wherein the hydraulic control unit (18) is not provided with a pump for discharging the brake fluid accumulated in the accumulator (53) from the accumulator (53), and the execution unit (62) In the pressure control, when the remaining capacity information of the accumulator (53) indicates that the remaining capacity of the accumulator (53) is low, an intervention suppression operation is performed to make it more difficult to intervene in the pressure reduction operation compared to when the remaining capacity information indicates that the remaining capacity is high.

2. The rider assistance system according to claim 1, wherein the pressure control is a slip control for suppressing slip of the wheels (13) of the lean vehicle (1).

3. The rider assistance system according to claim 2, wherein the execution unit (62) executes the pressure reduction operation when the degree of slip exceeds a threshold value in the slip control, and the execution unit (62) changes the threshold value so that the pressure reduction operation becomes less likely to be performed when the remaining capacity information indicates that the remaining capacity is low compared to when the remaining capacity information indicates that the remaining capacity is high in the intervention suppression operation.

4. The rider assistance system according to claim 2, wherein the execution unit (62) executes the pressure reduction operation when the degree of slip exceeds a minimum value in the slip control, and the execution unit (62) delays the start timing of the pressure reduction operation, which is based on the point in time when the degree of slip exceeds the minimum value, in the intervention suppression operation when the remaining capacity information indicates that the remaining capacity is low compared to when the remaining capacity information indicates that the remaining capacity is high.

5. The rider assistance system according to claim 1, wherein the pressure control is lift-up control for suppressing lift-up of a rear wheel (14) of the lean vehicle (1).

6. The rider assistance system according to claim 5, wherein the execution unit (62) executes the pressure reducing operation when the occurrence of the lift-up or the duration of the state in which the lift-up is likely to occur exceeds a minimum value in the lift-up control, and the execution unit (62) changes the minimum value so that the pressure reducing operation becomes less likely to be executed when the remaining capacity information indicates that the remaining capacity is low compared to when the remaining capacity information indicates that the remaining capacity is high in the intervention suppression operation.

7. The execution unit (62) executes the lift-up control by: 22 6. The rider assistance system according to claim 5, wherein when the occurrence of a lift-up or the duration of the state where there is a possibility of lift-up exceeds a minimum value, the pressure reduction operation is executed, and the execution unit (62) delays the start timing of the pressure reduction operation, based on the time when the duration exceeds the minimum value, in the intervention suppression operation when the remaining capacity information indicates that the remaining capacity is low compared to when the remaining capacity information indicates that the remaining capacity is high.

8. The execution unit (62) executes the lift-up control by:

6. The rider assistance system according to claim 5, wherein when the deceleration of the remaining capacity information exceeds a minimum value, the pressure reducing operation is performed, and when the remaining capacity information indicates that the remaining capacity is low, the execution unit (62) changes the minimum value so that the pressure reducing operation is less likely to be performed compared to when the remaining capacity information indicates that the remaining capacity is high.

9. The execution unit (62) executes the lift-up control by:

6. The rider assistance system according to claim 5, wherein when the deceleration of the remaining capacity information exceeds a minimum value, the pressure reduction operation is executed, and when the remaining capacity information indicates that the remaining capacity is low, the execution unit (62) delays the start timing of the pressure reduction operation, which is based on the point in time when the deceleration exceeds the minimum value, in the intervention suppression operation compared to when the remaining capacity information indicates that the remaining capacity is high. [Claim 1 ○] A rider assistance system as described in any one of claims 1 to 9, wherein the execution unit (62) switches the pressure control mode between a plurality of modes, executes the intervention suppression operation in some of the plurality of modes, and does not execute the intervention suppression operation in other some of the plurality of modes.

11. The plurality of modes includes an off-road mode which is a mode for off-road driving, and the execution unit (62) executes the intervention suppression operation in the off-road mode among the plurality of modes. A rider assistance system as described in claim 10.

12. The rider assistance system described in claim 10, wherein the execution unit (62) switches the pressure control mode based on manual setting information by the rider.

13. The rider assistance system according to claim 10, wherein the execution unit (62) automatically switches the pressure control mode based on road surface information.

14. The rider assistance system described in claim 10, wherein the execution unit (62) executes an alarm operation to notify the rider of the change in pressure control mode.

15. A control method for a rider assistance system (100) that assists a rider in driving a lean vehicle (1), the rider assistance system (100) comprising: The control device (60) includes a hydraulic pressure control unit (18) including an accumulator (53) and controlling the pressure of brake fluid in a wheel cylinder (16a) of the lean vehicle (1), and an execution unit (62) that executes pressure control to execute a pressure reducing operation to reduce the pressure of the brake fluid in the wheel cylinder (16a) by releasing the brake fluid from the wheel cylinder (16a) to the accumulator (53), wherein the hydraulic pressure control unit (18) is not provided with a pump that discharges the brake fluid accumulated in the accumulator (53) from the accumulator (53), and the execution unit (62) executes the pressure control by receiving information on the remaining capacity of the accumulator (53) from the accumulator (53). When the remaining capacity information indicates that the remaining capacity is low, an intervention suppression operation is performed that makes it more difficult to intervene in the pressure reduction operation compared to when the remaining capacity information indicates that the remaining capacity is high.

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