Patent Description:
Various techniques for improving safety of lean vehicles such as a motor cycle are known.

For example, PLT <NUM> discloses a driver assistance system. The driver assistance system has a sensor that detects an object located ahead of or substantially ahead of the lean vehicle in a travel direction. The driver assistance system makes a driver of the lean vehicle be informed that the lean vehicle approaches the object inappropriately based on information detected by the sensor.

A technique for a vehicle having four wheels as disclosed by prior art document <CIT> is known to increase a braking force based on a collision possibility while a brake is operated so that a driver can drive the vehicle safely. Such brake operation may be referred to as emergency brake assist (EBA). Here, it is considered to adopt the EBA for a lean vehicle to improve safety of the lean vehicle. However, a posture of the lean vehicle tends to be unstable as compared to a posture of the vehicle having the four wheels. As such, when the EBA increases the braking force automatically regardless of driver's operation, the lean vehicle may lose a balance. Losing the balance may results in unsafety of the driver.

The present invention addresses the above-described issues. It is an objective of the present disclosure to provide a controller and a control method capable of appropriately improving safety of a lean vehicle.

As one aspect of the present invention, a controller that controls behavior of a lean vehicle is provided as defined by independent claim <NUM>. The controller has a control section that performs a brake control to increase a braking force of the lean vehicle in a situation where a brake operation is performed by a rider of the lean vehicle. The control section performs the brake control based on a collision possibility that is determined in response to an output result from an environment sensor. The control section, in the brake control performed based on the collision possibility in the situation where the brake operation is performed by the rider, controls the braking force based on posture information of the lean vehicle. The control section, in the brake control performed based on the collision possibility in the situation where the brake operation is performed by the rider, changes an upper limit value of a degree of increase in the braking force and/or an upper limit value of the braking force, according to an operation amount of the brake operation.

As one aspect of the present invention, a control method for controlling behavior of a lean vehicle is provided, as defined by independent claim <NUM>. The control method includes: performing, with a control section, a brake control to increase a braking force applied to the lean vehicle in a situation where a brake operation is performed by a rider of the lean vehicle. The control section performs the brake control based on a collision possibility that is determined in response to an output result from an environment sensor. The control section, in the brake control performed based on the collision possibility in the situation where the brake operation is performed by the rider, controls the braking force based on posture information of the lean vehicle. The control section, in the brake control performed based on the collision possibility in the situation where the brake operation is performed by the rider, changes an upper limit value of a degree of increase in the braking force and/or an upper limit value of the braking force, according to an operation amount of the brake operation.

According to the present invention, the controller controls behavior of the lean vehicle. The controller has the control section that performs the brake control to increase the braking force of the lean vehicle. The control section performs the brake control based on the collision possibility that is determined in response to the output result from the environment sensor. The control section, in the brake control, controls the braking force based on posture information of the lean vehicle. According to the present invention, it is possible to suppress a posture of the lean vehicle from becoming unstable when the braking force is increased by the brake control. Therefore, it is possible to appropriately improve safety of the lean vehicle.

A description will hereinafter be made on a controller according to the present invention with reference to the drawings.

The following description will be made on the controller that is used for a two-wheeled motorcycle (see a lean vehicle <NUM> in <FIG>). However, a vehicle as a control target of the controller according to the present invention only needs to be a lean vehicle that travels in a state of being tilted in a turning direction during a turn, and may be a three-wheeled motorcycle, a pedal-driven vehicle, or the like, for example. The motorcycles include: a vehicle that has an engine as a propelling source; a vehicle that has an electric motor as the propelling source; and the like, and examples of the motorcycle are a bike, a scooter, and an electric scooter. The pedal-driven vehicle means a vehicle in general that can travel forward on a road by a depression force applied to pedals by a rider. The pedal-driven vehicles include a normal pedal-driven vehicle, an electrically-assisted pedal-driven vehicle, an electric pedal-driven vehicle, and the like.

In addition, the following description will be made on a case where each of a front-wheel brake mechanism and a rear-wheel brake mechanism is provided in one unit (see a front-wheel brake mechanism <NUM> and a rear-wheel brake mechanism <NUM> in <FIG>). However, at least one of the front-wheel brake mechanism and the rear-wheel brake mechanism may be provided in multiple units. Alternatively, one of the front-wheel brake mechanism and the rear-wheel brake mechanism may not be provided.

A configuration, action, and the like, which will be described below, merely constitute one example. The controller and a control method according to the present invention are not limited to a case with such a configuration, such action, and the like.

The same or similar description will appropriately be simplified or will not be made below. In the drawings, the same or similar members or portions will not be denoted by a reference sign or will be denoted by the same reference sign. A detailed structure will appropriately be illustrated in a simplified manner or will not be illustrated.

A description will be made on a configuration of the lean vehicle <NUM> according to an embodiment of the present invention with reference to <FIG>.

<FIG> is a schematic view illustrating an outline configuration of the lean vehicle <NUM>. <FIG> is a schematic view illustrating an outline configuration of a brake system <NUM>. <FIG> is a block diagram illustrating an exemplary functional configuration of a controller <NUM>.

The lean vehicle <NUM> is a two-wheeled motorcycle that corresponds to an example of the lean vehicle according to the present invention. As illustrated in <FIG>, the lean vehicle <NUM> includes: a trunk <NUM>; a handlebar <NUM> that is held by the trunk <NUM> in a freely turnable manner; a front wheel <NUM> that is held by the trunk <NUM> in a freely turnable manner with the handlebar <NUM>; a rear wheel <NUM> that is held by the trunk <NUM> in a freely rotatable manner; the brake system <NUM>; a hydraulic pressure control unit <NUM> that is provided to the brake system <NUM>; and the controller (ECU) <NUM> that is provided to the hydraulic pressure control unit <NUM>. The lean vehicle <NUM> is also provided with, as sensors, a front-wheel rotational frequency sensor <NUM>, a rear-wheel rotational frequency sensor <NUM>, an inertial measurement unit (IMU) <NUM>, an environment sensor <NUM>, and a master-cylinder pressure sensor <NUM> (see <FIG>). The lean vehicle <NUM> includes a drive source such as an engine or a motor and travels by using power that is output from the drive source.

As illustrated in <FIG> and <FIG>, the brake system <NUM> includes: a first brake operation section <NUM>; the front-wheel brake mechanism <NUM> that brakes the front wheel <NUM> in an interlocking manner with at least the first brake operation section <NUM>; a second brake operation section <NUM>; and the rear-wheel brake mechanism <NUM> that brakes the rear wheel <NUM> in an interlocking manner with at least the second brake operation section <NUM>. The brake system <NUM> also includes the hydraulic pressure control unit <NUM>, and the front-wheel brake mechanism <NUM> and the rear-wheel brake mechanism <NUM> are partially included in the hydraulic pressure control unit <NUM>. The hydraulic pressure control unit <NUM> is a unit that has a function of controlling a braking force to be generated on the front wheel <NUM> by the front-wheel brake mechanism <NUM> and a braking force to be generated on the rear wheel <NUM> by the rear-wheel brake mechanism <NUM>.

The first brake operation section <NUM> is provided to the handlebar <NUM> and is operated by the rider's hand. The first brake operation section <NUM> is a brake lever, for example. The second brake operation section <NUM> is provided to a lower portion of the trunk <NUM> and is operated by the rider's foot. The second brake operation section <NUM> is a brake pedal, for example. However, like a brake operation section of the scooter or the like, each of the first brake operation section <NUM> and the second brake operation section <NUM> may be the brake lever that is operated by the rider's hand.

Each of the front-wheel brake mechanism <NUM> and the rear-wheel brake mechanism <NUM> includes: a master cylinder <NUM> in which a piston (not illustrated) is installed; a reservoir <NUM> that is attached to the master cylinder <NUM>; a brake caliper <NUM> that is held by the trunk <NUM> and has a brake pad (not illustrated) ; a wheel cylinder <NUM> that is provided to the brake caliper <NUM>; a primary channel <NUM> through which a brake fluid in the master cylinder <NUM> flows into the wheel cylinder <NUM>; a secondary channel <NUM> through which the brake fluid in the wheel cylinder <NUM> is released; and a supply channel <NUM> through which the brake fluid in the master cylinder <NUM> is supplied to the secondary channel <NUM>.

An inlet valve (EV) <NUM> is provided to the primary channel <NUM>. The secondary channel <NUM> bypasses a portion of the primary channel <NUM> between the wheel cylinder <NUM> side and the master cylinder <NUM> side of the inlet valve <NUM>. The secondary channel <NUM> is sequentially provided with an outlet valve (AV) <NUM>, an accumulator <NUM>, and a pump <NUM> from an upstream side. Between an end on the master cylinder <NUM> side of the primary channel <NUM> and a portion of the primary channel <NUM> to which a downstream end of the secondary channel <NUM> is connected, a first valve (USV) <NUM> is provided. The supply channel <NUM> communicates between the master cylinder <NUM> and a portion on a suction side of the pump <NUM> in the secondary channel <NUM>. A second valve (HSV) <NUM> is provided to the supply channel <NUM>.

The inlet valve <NUM> is an electromagnetic valve that is opened in an unenergized state and closed in an energized state, for example. The outlet valve <NUM> is an electromagnetic valve that is closed in an unenergized state and opened in an energized state, for example. The first valve <NUM> is an electromagnetic valve that is opened in an unenergized state and is closed in an energized state, for example. The second valve <NUM> is an electromagnetic valve that is closed in an unenergized state and is opened in an energized state, for example.

The hydraulic pressure control unit <NUM> includes: components such as the inlet valves <NUM>, the outlet valves <NUM>, the accumulators <NUM>, the pumps <NUM>, the first valves <NUM>, and the second valves <NUM> used to control a brake hydraulic pressure; a base body <NUM> to which those components are provided and in which channels constituting the primary channels <NUM>, the secondary channels <NUM>, and the supply channels <NUM> are formed; and the controller <NUM>.

The base body <NUM> may be formed of one member or may be formed of multiple members. In addition, in the case where the base body <NUM> is formed of the multiple members, the components may separately be provided to the different members.

The controller <NUM> controls action of each of the components in the hydraulic pressure control unit <NUM>. As a result, the braking force generated on the front wheel <NUM> by the front-wheel brake mechanism <NUM> and the braking force generated on the rear wheel <NUM> by the rear-wheel brake mechanism <NUM> are controlled.

During a normal time (that is, when the braking force corresponding to a brake operation by the rider is set to be generated on the wheels), the controller <NUM> opens the inlet valves <NUM>, closes the outlet valves <NUM>, opens the first valves <NUM>, and closes the second valves <NUM>. When the first brake operation section <NUM> is operated in such a state, in the front-wheel brake mechanism <NUM>, the piston (not illustrated) in the master cylinder <NUM> is pressed to increase a hydraulic pressure of the brake fluid in the wheel cylinder <NUM>, the brake pad (not illustrated) of the brake caliper <NUM> is then pressed against a rotor 3a of the front wheel <NUM>, and the braking force is thereby generated on the front wheel <NUM>. Meanwhile, when the second brake operation section <NUM> is operated, in the rear-wheel brake mechanism <NUM>, the piston (not illustrated) in the master cylinder <NUM> is pressed to increase the hydraulic pressure of the brake fluid in the wheel cylinder <NUM>, the brake pad (not illustrated) of the brake caliper <NUM> is then pressed against a rotor 4a of the rear wheel <NUM>, and the braking force is thereby generated on the rear wheel <NUM>.

The front-wheel rotational frequency sensor <NUM> is a rotational frequency sensor that detects a rotational frequency of the front wheel <NUM> (for example, a rotational frequency of the front wheel <NUM> per unit time [rpm], a travel distance of the front wheel <NUM> per unit time [km/h], or the like), and outputs a detection result. The front-wheel rotational frequency sensor <NUM> may detect another physical quantity that can substantially be converted to the rotational frequency of the front wheel <NUM>. The front-wheel rotational frequency sensor <NUM> is provided to the front wheel <NUM>.

The rear-wheel rotational frequency sensor <NUM> is a rotational frequency sensor that detects a rotational frequency of the rear wheel <NUM> (for example, the rotational frequency of the rear wheel <NUM> per unit time [rpm], a travel distance of the rear wheel <NUM> per unit time [km/h], or the like), and outputs a detection result. The rear-wheel rotational frequency sensor <NUM> may detect another physical quantity that can substantially be converted to the rotational frequency of the rear wheel <NUM>. The rear-wheel rotational frequency sensor <NUM> is provided to the rear wheel <NUM>.

The inertial measurement unit <NUM> includes a three-axis gyroscope sensor and a three-directional acceleration sensor, and detects a posture of the lean vehicle <NUM>. For example, the inertial measurement unit <NUM> detects a pitching angle of the lean vehicle <NUM> (more specifically, a tilt angle in a pitching direction with respect to a horizontal direction in a front direction of the lean vehicle <NUM>), and outputs a detection result. The inertial measurement unit <NUM> may detect another physical quantity that can substantially be converted to the pitching angle of the lean vehicle <NUM>. In addition, for example, the inertial measurement unit <NUM> detects a lean angle of the lean vehicle <NUM> (more specifically, a tilt angle in a rolling direction with respect to a vertical direction in an upward direction of the lean vehicle <NUM>), and outputs a detection result. The inertial measurement unit <NUM> may detect another physical quantity that can substantially be converted to the lean angle of the lean vehicle <NUM>. The inertial measurement unit <NUM> is provided to the trunk <NUM>, for example.

The environment sensor <NUM> detects environment information on environment in front of the lean vehicle <NUM>. For example, the environment sensor <NUM> detects a preceding vehicle that is a vehicle located in front of the lean vehicle <NUM>, and detects an inter-vehicular distance between the lean vehicle <NUM> and the preceding vehicle and a relative speed of the lean vehicle <NUM> to the preceding vehicle. The environment sensor <NUM> may detect another physical quantity that can substantially be converted to the inter-vehicular distance between the lean vehicle <NUM> and the preceding vehicle. In addition, the environment sensor <NUM> may detect another physical quantity that can substantially be converted to the relative speed of the lean vehicle <NUM> to the preceding vehicle. The environment sensor <NUM> is provided to a front portion of the trunk <NUM>, for example. Here, the environment sensor <NUM> may detect, instead of the preceding vehicle, an object (for example, a road facility, a fallen object, a person, an animal, or the like) that is located in front of the lean vehicle <NUM>, and may detect an inter-vehicular distance between the lean vehicle <NUM> and the object and a relative speed of the lean vehicle <NUM> to the object.

As the environment sensor <NUM>, for example, a camera that captures an image in front of the lean vehicle <NUM> and a radar that can detect a distance from the lean vehicle <NUM> to a target in front are used. When the preceding vehicle is detected by using the image captured by the camera and the detection result of the preceding vehicle and a detection result by the radar are used, it is possible to detect the inter-vehicular distance between the lean vehicle <NUM> and the preceding vehicle and the relative speed of the lean vehicle <NUM> to the preceding vehicle. The configuration of the environment sensor <NUM> is not limited to that in the above example. For example, a stereo camera may be used as the environment sensor <NUM>.

The master-cylinder pressure sensor <NUM> detects the brake hydraulic pressure in the master cylinder <NUM> (that is, a master cylinder pressure), and outputs a detection result. The master-cylinder pressure sensor <NUM> may detect another physical quantity that can substantially be converted to the master cylinder pressure. More specifically, the master-cylinder pressure sensor <NUM> is provided to each of the front-wheel brake mechanism <NUM> and the rear-wheel brake mechanism <NUM>. In this way, the master cylinder pressure of the master cylinder <NUM> attached to the first brake operation section <NUM> and the master cylinder pressure of the master cylinder <NUM> attached to the second brake operation section <NUM> are separately detected.

The controller <NUM> controls behavior of the lean vehicle <NUM>. For example, the controller <NUM> is partially or entirely constructed of a microcomputer, a microprocessor unit, or the like. Alternatively, the controller <NUM> may partially or entirely be constructed of a member in which firmware or the like can be updated, or may partially or entirely be a program module or the like that is executed by a command from a CPU or the like, for example. The controller <NUM> may be provided as one unit or may be divided into multiple units, for example.

As illustrated in <FIG>, the controller <NUM> includes an acquisition section <NUM> and a control section <NUM>, for example.

The acquisition section <NUM> acquires information from each of the devices mounted to the lean vehicle <NUM>, and outputs the acquired information to the control section <NUM>. For example, the acquisition section <NUM> acquires information from the front-wheel rotational frequency sensor <NUM>, the rear-wheel rotational frequency sensor <NUM>, the inertial measurement unit <NUM>, the environment sensor <NUM>, and the master-cylinder pressure sensor <NUM>.

In order to control the behavior of the lean vehicle <NUM>, the control section <NUM> executes braking control (that is, control of the braking force generated on the lean vehicle <NUM>). More specifically, in the braking control, the control section <NUM> controls the action of each of the components of the hydraulic pressure control unit <NUM> in the brake system <NUM>.

As described above, during the normal time, the control section <NUM> controls the operation of each of the components in the hydraulic pressure control unit <NUM> such that the braking force corresponding to the brake operation by the rider is generated on the wheels. Meanwhile, in a particular case, the control section <NUM> executes different braking control from that during the normal time.

For example, in the case where the wheel is locked or possibly locked, the control section <NUM> executes anti-lock brake control. In the anti-lock brake control, the braking force of the wheel is adjusted to such a braking force with which locking of the wheel can be avoided.

During execution of the anti-lock brake control, the control section <NUM> brings the lean vehicle <NUM> into a state where the inlet valve <NUM> is closed, the outlet valve <NUM> is opened, the first valve <NUM> is opened, and the second valve <NUM> is closed, and drives the pump <NUM> in such a state, so as to reduce the hydraulic pressure of the brake fluid in the wheel cylinder <NUM> and thereby reduce the braking force generated on the wheel. Then, the control section <NUM> closes both of the inlet valve <NUM> and the outlet valve <NUM> from the above state, so as to keep the hydraulic pressure of the brake fluid in the wheel cylinder <NUM> and keep the braking force generated on the wheel. Thereafter, the control section <NUM> opens the inlet valve <NUM> and closes the outlet valve <NUM>, so as to increase the hydraulic pressure of the brake fluid in the wheel cylinder <NUM> and thereby increase the braking force generated on the wheel.

During the execution of the anti-lock brake control, the above control for reducing the braking force generated on the wheel (that is, braking force reduction control), the above control for keeping the braking force generated on the wheel (that is, braking force keeping control), and the above control for increasing the braking force generated on the wheel (that is, braking force increase control) are repeatedly executed in this order.

Here, in the case where a collision possibility with the preceding vehicle exceeds a reference in a situation where the brake operation is performed by the rider of the lean vehicle <NUM>, the control section <NUM> performs a brake control referred to as an emergency brake assist (EBA). The EBA increases the braking force of the lean vehicle <NUM>. Increasing the braking force of the lean vehicle <NUM> means increasing the braking force of the lean vehicle <NUM> to be larger than the braking force that corresponds to the brake operation. In the EBA, the braking force of the lean vehicle <NUM> is adjusted to such a magnitude of a braking force that can improve avoidability of the collision with the preceding vehicle.

The collision possibility is acquired based on an output result of the environment sensor <NUM>. For example, based on the inter-vehicular distance between the lean vehicle <NUM> and the preceding vehicle and the relative speed of the lean vehicle <NUM> to the preceding vehicle, the control section <NUM> determines whether the collision possibility with the preceding vehicle exceeds the reference. For example, in the case where duration before reaching the preceding vehicle, which is determined from the inter-vehicular distance and the relative speed, is excessively short, the control section <NUM> determines that the collision possibility with the preceding vehicle exceeds the reference, and initiates the EBA.

During actuation of the EBA, the control section <NUM> brings the lean vehicle <NUM> into a state where the inlet valve <NUM> is opened, the outlet valve <NUM> is closed, the first valve <NUM> is closed, and the second valve <NUM> is opened, and drives the pump <NUM>, so as to increase the hydraulic pressure of the brake fluid in the wheel cylinder <NUM>. In this way, it is possible to increase the braking force generated on the wheel to be larger than the braking force that corresponds to the brake operation. That is, it is possible to increase the braking force on the lean vehicle <NUM>. In the EBA, the control section <NUM> separately controls the front-wheel brake mechanism <NUM> and the rear-wheel brake mechanism <NUM>, and can thereby separately control the braking force on the front wheel <NUM> and the braking force on the rear wheel <NUM>. In the EBA, for example, the braking forces on the front wheel <NUM> and the rear wheel <NUM> are controlled such that a ratio between the braking force on the front wheel <NUM> and the braking force on the rear wheel <NUM> becomes a target ratio, which is set in advance.

As described above, in the controller <NUM>, the control section <NUM> performs the EBA according to the collision possibility in the situation where the brake operation is performed by the rider of the lean vehicle <NUM>. Here, in the EBA, the control section <NUM> controls the braking force of the lean vehicle <NUM> based on posture information of the lean vehicle <NUM>. In this way, safety of the lean vehicle <NUM> is appropriately improved. A detailed description will be made below on such processing related to the EBA and performed by the controller <NUM>.

A description will be made on action of the controller <NUM> according to the embodiment of the present invention with reference to <FIG>.

As described above, in this embodiment, the control section <NUM> performs the EBA according to the collision possibility in the situation where the brake operation is performed by the rider of the lean vehicle <NUM>.

<FIG> is a schematic graph illustrating an exemplary relationship between the braking force that corresponds to the brake operation in the EBA and the braking force of the lean vehicle <NUM>. In <FIG>, a horizontal axis T represents time, and a vertical axis B represents the braking force. In addition, in <FIG>, a broken line L1 represents the braking force that corresponds to the brake operation, and a solid line L2 represents the braking force of the lean vehicle <NUM>.

As illustrated in <FIG>, in the EBA, the braking force of the lean vehicle <NUM> represented by the solid line L2 is controlled to be larger than the braking force corresponding to the brake operation and represented by the broken line L1. That is, the braking force of the lean vehicle <NUM> is increased. In this way, the avoidability of the collision with the preceding vehicle is improved.

Here, when the braking force applied to the lean vehicle <NUM> is increased rapidly and drastically, the posture of the lean vehicle <NUM> may become unstable. For example, when the braking force is increased rapidly and drastically, a suspension of the lean vehicle <NUM> may shrins rapidly, and therefore the posture of the lean vehicle <NUM> changes rapidly and drastically.

The present embodiment addresses the above-described issues. Specifically, the control section <NUM>, during the EBA, controls the braking force of the lean vehicle <NUM> based on the posture information of the lean vehicle <NUM> so that the posture of the lean vehicle <NUM> is prevented from being unstable. More specifically, the control section <NUM> adjusts a degree of increase in the braking force based on the posture information of the lean vehicle <NUM> so that the braking force is prevented from increasing rapidly and drastically. Thus, the posture of the lean vehicle <NUM> can be kept stable even when the braking force is increased during the EBA. Hereinafter, a flow of a processing relating to the EBA performed by the controller <NUM> will be described with a first example and a second example.

<FIG> is a flowchart illustrating the first example of the processing procedure related to the EBA and executed by the controller <NUM>. A control flow illustrated in <FIG> is initiated when an initiation condition of the EBA (that is, a condition that the collision possibility with the preceding vehicle exceeds the reference) is satisfied. Step S101 in <FIG> corresponds to the initiation of the control flow illustrated in <FIG>. In the control flow illustrated in <FIG>, processing in steps S102 to S105 corresponds to a single calculation cycle, and each calculation cycle is repeated at specified time intervals. However, in the case where a termination condition of the EBA is satisfied in the middle of the control flow illustrated in <FIG>, the control flow illustrated in <FIG> is terminated. As the termination condition of the EBA, for example, a condition that the brake operation by the rider is canceled can be used.

When the control flow illustrated in <FIG> is initiated, in step S102, the control section <NUM> determines a target increase amount of the braking force (that is, a target value of an increase amount of the braking force) of the lean vehicle <NUM> in the current calculation cycle.

Here, in the control flow illustrated in <FIG>, as will be described below, the control section <NUM> increases the braking force of the lean vehicle <NUM> by a specified increase amount in each calculation cycle. That is, the increase amount of the braking force that is determined in each calculation cycle is an amount by which the braking force is increased per calculation cycle. In other words, the increase amount of the braking force determined in each calculation corresponds to the degree of increase in the braking force of the lean vehicle <NUM>.

The control section <NUM> sets, as the target increase amount, such an increase amount of the braking force that can improve the avoidability of the collision with the preceding vehicle. For example, the control section <NUM> determines the target increase amount based on the inter-vehicular distance between the lean vehicle <NUM> and the preceding vehicle and the relative speed of the lean vehicle <NUM> to the preceding vehicle. However, the control section <NUM> may determine the target increase amount in consideration of relative acceleration of the lean vehicle <NUM> to the preceding vehicle.

Next, in step S103, the control section <NUM> determines whether the target increase amount of the braking force is equal to or smaller than an maximum increase amount (that is, an upper limit value of the increase amount). If it is determined that the target increase amount of the braking force is equal to or smaller than the maximum increase amount (step S103/YES), the processing proceeds to step S104, and the control section <NUM> increases the braking force of the lean vehicle <NUM> by the target increase amount. On the other hand, if it is determined that the target increase amount of the braking force is larger than the maximum increase amount (step S103/NO), the processing proceeds to step S105, and the control section <NUM> increases the braking force of the lean vehicle <NUM> by the maximum increase amount.

After step S104 or step S105, the processing returns to step S102, and the next calculation cycle is performed.

As described above, in the control flow illustrated in <FIG>, the increase amount of the braking force of the lean vehicle <NUM> is limited to the maximum increase amount in each calculation cycle. Here, the maximum increase amount corresponds to an upper limit value of the degree of increase in the braking force of the lean vehicle <NUM>. The control section <NUM> changes the maximum increase amount (i.e., the upper limit value of the degree of increase in the braking force of the lean vehicle <NUM>) based on the posture information of the lean vehicle <NUM>. The posture information is information on a physical quantity that is reflected to the posture of the lean vehicle <NUM>.

For example, the posture information includes pitching angle information of the lean vehicle <NUM>. The pitching angle information is information on the pitching angle of the lean vehicle <NUM> and can include, for example, information indicative of the pitching angle or information indicative of a pitch angular velocity (that is, a time rate of change of the pitching angle).

For example, the control section <NUM> reduces the maximum increase amount as an absolute value of the pitching angle or an absolute value of the pitch angular velocity of the lean vehicle <NUM> is increased. Here, the posture of the lean vehicle <NUM> is more likely to be changed in the pitching direction as the absolute value of the pitching angle or the absolute value of the pitch angular velocity of the lean vehicle <NUM> is increased. Accordingly, when the posture of the lean vehicle <NUM> is changed in the pitching direction easily, the control section <NUM> prevents the braking force of the lean vehicle <NUM> from increasing rapidly and drastically. Thus, the posture of the lean vehicle <NUM> can be prevented from changing rapidly in the pitching direction.

For example, the posture information includes lean angle information of the lean vehicle <NUM>. The lean angle information is information on the lean angle of the lean vehicle <NUM> and can include, for example, information indicative of the lean angle or information indicative of a lean angular velocity (that is, a time rate of change of the lean angle).

For example, the control section <NUM> reduces the maximum increase amount as an absolute value of the lean angle or an absolute value of the lean angular velocity of the lean vehicle <NUM> is increased. Here, the posture of the lean vehicle <NUM> is more likely to be changed in the rolling direction as the absolute value of the lean angle or the absolute value of the lean angular velocity of the lean vehicle <NUM> is increased. Accordingly, when the posture of the lean vehicle <NUM> is changed in the rolling direction easily, the control section <NUM> prevents the braking force from increasing rapidly and drastically. Thus, the posture of the lean vehicle <NUM> can be prevented from changing rapidly in the rolling direction.

For example, the posture information includes acceleration/deceleration information of the lean vehicle <NUM>. The acceleration/deceleration information is information on acceleration/deceleration of the lean vehicle <NUM>. For example, the control section <NUM> can acquire the acceleration/deceleration information based on the rotational frequency of the front wheel <NUM> and the rotational frequency of the rear wheel <NUM>.

For example, the control section <NUM> reduces the maximum increase amount as the deceleration of the lean vehicle <NUM> is increased. In this way, the control section <NUM> controls the degree of increase in the braking force of the lean vehicle appropriately so that the posture of the lean vehicle <NUM> is kept stable. That is, the control section <NUM> prevents the posture of the lean vehicle <NUM> from changing rapidly due to the rapid increase of the braking force of the lean vehicle <NUM>. For example, such a rapid change in the posture of the lean vehicle <NUM> may be a rear lift-p, which is lifting of a rear portion of the lean vehicle <NUM>.

Here, in the EBA, the control section <NUM> may control the braking force of the lean vehicle <NUM> in consideration of an operation amount of the brake operation by the rider. The operation amount of the brake operation is an index indicative of an operation amount of the brake operation section (more specifically, the first brake operation section <NUM> or the second brake operation section <NUM>). For example, the operation amount related to the first brake operation section <NUM> may be the master cylinder pressure of the master cylinder <NUM>, which is attached to the first brake operation section <NUM>, or may be the operation amount itself of the first brake operation section <NUM> (that is, a brake operation amount). In addition, for example, the operation amount related to the second brake operation section <NUM> may be the master cylinder pressure of the master cylinder <NUM>, which is attached to the second brake operation section <NUM>, or may be the operation amount itself of the second brake operation section <NUM> (that is, the brake operation amount).

For example, in the control flow illustrated in <FIG>, the control section <NUM> may change the maximum increase amount (i.e., the upper limit value of the degree of increase in the braking force of the lean vehicle <NUM>) according to the operation amount by the rider. For example, the control section <NUM> may limit the maximum increase amount to be equal to or smaller than a value that is acquired by multiplying the increase amount per unit time of the braking force corresponding to the brake operation by a specified factor. Alternatively, for example, the control section <NUM> may limit the maximum increase amount to be equal to or smaller than a value that is acquired by adding a specified value to the increase amount per unit time of the braking force corresponding to the brake operation. In this way, it is possible to suppress the rapid increase in the braking force of the lean vehicle <NUM> that contradicts the rider's intention. Here, the rider may be able to set the maximum increase amount. In such a case, the control section <NUM> may determine the maximum increase amount according to a setting operation for the maximum increase amount by the rider.

<FIG> is a flowchart illustrating the second example of the processing procedure related to the EBA and executed by the controller <NUM>. A control flow illustrated in <FIG> is initiated when the initiation condition of the EBA is satisfied. Step S201 in <FIG> corresponds to the initiation of the control flow illustrated in <FIG>. In the control flow illustrated in <FIG>, processing in steps S202 to S205 corresponds to the single calculation cycle, and each calculation cycle is repeated at the specified time intervals. Similar to the control flow illustrated in <FIG>, in the case where the termination condition of the EBA is satisfied in the middle of the control flow illustrated in <FIG>, the control flow illustrated in <FIG> is terminated.

When the control flow illustrated in <FIG> is initiated, in step S202, the control section <NUM> determines the target braking force (that is, the target value of the braking force) of the lean vehicle <NUM> in the current calculation cycle.

The control section <NUM> sets, as the target braking force, such a magnitude of the braking force that can improve the avoidability of the collision with the preceding vehicle. For example, the control section <NUM> determines the target braking force based on the inter-vehicular distance between the lean vehicle <NUM> and the preceding vehicle and the relative speed of the lean vehicle <NUM> to the preceding vehicle.

Next, in step S203, the control section <NUM> determines whether the target braking force is equal to or smaller than an maximum braking force (that is, an upper limit value of the braking force). If it is determined that the target braking force is equal to or smaller than the maximum braking force (step S203/YES), the processing proceeds to step S204, and the control section <NUM> controls the braking force of the lean vehicle <NUM> to the target braking force. On the other hand, if it is determined that the target braking force is larger than the maximum braking force (step S203/NO), the processing proceeds to step S205, and the control section <NUM> controls the braking force of the lean vehicle <NUM> to the maximum braking force.

After step S204 or step S205, the processing returns to step S202, and the next calculation cycle is performed.

As described above, in the control flow illustrated in <FIG>, in each calculation cycle, the braking force of the lean vehicle <NUM> is limited to the maximum braking force. In this way, similar to the control flow illustrated in <FIG>, the control section <NUM> prevents the degree of increase in the braking force of the lean vehicle <NUM> from becoming excessively acute. The control section <NUM> changes the maximum braking force (that is, the upper limit value of the braking force of the lean vehicle <NUM>) based on the posture information of the lean vehicle <NUM>. As described above, the posture information is the information on the physical quantity that is reflected to the posture of the lean vehicle <NUM>, and can include the pitching angle information, the lean angle information, or the acceleration/deceleration information, for example.

For example, the control section <NUM> reduces the maximum braking force as the absolute value of the pitching angle or the absolute value of the pitch angular velocity of the lean vehicle <NUM> is increased. Accordingly, when the posture of the lean vehicle <NUM> is changed in the pitching direction easily, the control section <NUM> prevents the braking force of the lean vehicle <NUM> from changing rapidly and drastically. Thus, the control section <NUM> suppress the rapid change in the posture of the lean vehicle <NUM> in the pitching direction.

In addition, for example, the control section <NUM> reduces the maximum braking force as the absolute value of the lean angle or the absolute value of the lean angular velocity of the lean angle of the lean vehicle <NUM> is increased. In this way, when the posture of the lean vehicle <NUM> changes in the rolling direction easily, the control section <NUM> prevents the braking force of the lean vehicle <NUM> from increasing rapidly and drastically. Thus, the control section <NUM> suppress the rapid change in the posture of the lean vehicle <NUM> in the rolling direction.

In addition, for example, the control section <NUM> reduces the maximum braking force as the deceleration of the lean vehicle <NUM> is increased. In this way, the control section <NUM> adjusts the degree of increase in the braking force of the lean vehicle <NUM> appropriately. Thus, the posture of the lean vehicle <NUM> is kept stable.

As described above, in the EBA, the control section <NUM> may control the braking force of the lean vehicle <NUM> in consideration of the operation amount of the brake operation by the rider. For example, in the control flow illustrated in <FIG>, the control section <NUM> may change the maximum braking force (that is, the upper limit value of the braking force of the lean vehicle <NUM>) according to the operation amount by the rider. For example, the control section <NUM> may limit the maximum braking force to be equal to or smaller than a value that is acquired by multiplying the braking force corresponding to the brake operation by a specified factor. Alternatively, for example, the control section <NUM> may limit the maximum braking force to be equal to or smaller than a value that is acquired by adding a specified value to the braking force corresponding to the brake operation. In this way, it is possible to suppress the rapid increase in the braking force of the lean vehicle <NUM> that contradicts the rider's intention. Here, the rider may be able to set the maximum braking force. In such a case, the control section <NUM> may determine the maximum braking force according to a setting operation for the maximum braking force by the rider.

A description will be made on effects of the controller <NUM> according to the embodiment of the present invention.

In the controller <NUM>, the control section <NUM> controls the braking force of the lean vehicle <NUM> based on the posture information of the lean vehicle <NUM> in the EBA. In this way, in the EBA, the control section <NUM> adjusts the degree of increase in the braking force appropriately based on the posture information of the lean vehicle <NUM>. Specifically, the control section <NUM> suppresses the degree of increase in the braking force from becoming excessively acute. Thus, it is possible to suppress the posture of the lean vehicle <NUM> from becoming unstable when the EBA increases the braking force. Therefore, it is possible to appropriately improve the safety of the lean vehicle <NUM>.

According to an aspect of the invention, according to the controller <NUM> of the present invention, the control section <NUM> changes the upper limit value of the degree of increase in the braking force of the lean vehicle <NUM> based on the posture information of the lean vehicle <NUM> during the EBA. In this way, the control section <NUM> adjusts the degree of increase in the braking force appropriate not to become excessively acute. Therefore, it is possible to appropriately suppress the posture of the lean vehicle <NUM> from becoming unstable when the EBA increases the braking force.

According to an aspect of the invention, in the controller <NUM>, the control section <NUM> changes the upper limit value of the braking force of the lean vehicle <NUM> based on the posture information of the lean vehicle <NUM> in the EBA. In this way, the control section <NUM> adjusts the degree of increase in the braking force appropriately so that the degree of increase in the braking force does not become excessively acute. Therefore, it is possible to appropriately suppress the posture of the lean vehicle <NUM> from becoming unstable when the EBA increases the braking force.

Preferably, in the controller <NUM>, the posture information includes the pitching angle information of the lean vehicle <NUM>. In this way, the controller <NUM> adjusts the degree of increase in the braking force appropriately based on the pitching angle information of the lean vehicle <NUM>. Accordingly, when the posture of the lean vehicle <NUM> changes in the pitching direction easily, the controller <NUM> suppresses a rapid change in the posture of the lean vehicle <NUM> in the pitching direction by preventing the braking force of the lean vehicle <NUM> from increasing rapidly and drastically.

Preferably in the controller <NUM>, the posture information includes the lean angle information of the lean vehicle <NUM>. In this way, the controller <NUM> adjusts the degree of increase in the braking force appropriately based on the lean angle information of the lean vehicle <NUM>. Accordingly, in the case where the posture of the lean vehicle <NUM> is likely to be changed in the rolling direction, it is possible to suppress a rapid change in the posture of the lean vehicle <NUM> in the rolling direction by preventing the braking force of the lean vehicle <NUM> from increasing rapidly and drastically.

Preferably, in the controller <NUM>, the posture information includes the acceleration/deceleration information of the lean vehicle <NUM>. In this way, the controller <NUM> adjusts the degree of increase in the braking force appropriately based on the acceleration/deceleration information of the lean vehicle <NUM>. Therefore, the posture of the lean vehicle <NUM> is kept stable.

Preferably, in the controller <NUM>, the control section <NUM> controls the braking force of the lean vehicle <NUM> in consideration of the operation amount of the brake operation by the rider in the EBA. In this way, it is possible to suppress the rapid increase in the braking force of the lean vehicle <NUM> that contradicts the rider's intention. Therefore, it is possible to further improve the safety of the lean vehicle <NUM>.

Preferably, in the controller <NUM>, the control section <NUM> changes the upper limit value of the degree of increase in the braking force of the lean vehicle <NUM> according to the operation amount by the rider in the EBA. In this way, it is possible to appropriately suppress the rapid increase in the braking force of the lean vehicle <NUM> that contradicts the rider's intention.

Preferably, in the controller <NUM>, the control section <NUM> changes the upper limit value of the braking force of the lean vehicle <NUM> according to the operation amount by the rider in the EBA. In this way, it is possible to appropriately suppress the rapid increase in the braking force of the lean vehicle <NUM> that contradicts the rider's intention.

Claim 1:
A controller (<NUM>) that controls behavior of a lean vehicle (<NUM>), the controller comprising:
a control section (<NUM>) configured to perform a brake control to increase a braking force of the lean vehicle (<NUM>) in a situation where a brake operation is performed by a rider of the lean vehicle (<NUM>), the control section (<NUM>) configured to perform the brake control based on a collision possibility that is determined in response to an output result from an environment sensor (<NUM>), wherein
the control section (<NUM>), in the brake control performed based on the collision possibility in the situation where the brake operation is performed by the rider, controls the braking force based on posture information of the lean vehicle (<NUM>), and characterised in that
the control section (<NUM>), in the brake control performed based on the collision possibility in the situation where the brake operation is performed by the rider, changes an upper limit value of a degree of increase in the braking force and/or an upper limit value of the braking force, according to an operation amount of the brake operation.