Patent Description:
As a conventional technique related to a motorcycle, a technique of assisting with an operation by a driver has been available.

For example, a driver assistance system is disclosed in <CIT>. Based on information detected by a sensor that detects presence of an obstacle in a travel direction or substantially in the travel direction, the driver assistance system warns a driver of the motorcycle that the motorcycle inappropriately approaches the obstacle.

Further, <CIT> describes a motorcycle comprising a brake control unit that is configured to automatically control operation of a brake/drive system in order to adjust and maintain a desired speed of the motorcycle or to maintain a predefined distance to a vehicle driving ahead of the motorcycle. <CIT> describes a method to control skid motion of a wheel of a motorcycle by decelerating or accelerating a respective wheel of the motorcycle, wherein, for calculating skid motion acceleration, a bank angle, a velocity of the motorcycle, a yaw rate, and a lateral acceleration.

In order to assist with the operation by the driver, use of an automatic cruise travel mode is considered. The automatic cruise travel mode is a travel mode in which the motorcycle continues traveling with behavior thereof being at least partially controlled automatically. In the automatic cruise travel mode, for example, the motorcycle is controlled that a distance therefrom to a preceding vehicle approximates a distance reference value. For this reason, the motorcycle is possibly controlled to perform an automatic cruise deceleration operation in which the motorcycle decelerates regardless of presence or absence of the operation by the driver in the automatic cruise travel mode. Here, the motorcycle tends to have unstable posture when compared to a four-wheeled vehicle, for example. This leads to such a problem that the motorcycle possibly falls over due to deceleration by the automatic cruise deceleration operation.

The invention has been made with the above-described problem as the background and therefore obtains a controller and a control method capable of appropriately assisting with an operation by a driver while preventing a motorcycle from falling over.

As a solution to this problem, the invention provides a controller in accordance with claim <NUM> and a control method in accordance with claim <NUM>.

In the controller and the control method according to the invention, in the control mode to make the motorcycle perform the automatic cruise deceleration operation, the automatic deceleration that is the deceleration of the motorcycle generated by the automatic cruise deceleration operation is controlled in accordance with the lean angle of the motorcycle. In this way, the automatic deceleration can appropriately be controlled in accordance with posture of the motorcycle. Therefore, an operation by a driver can appropriately be assisted while falling of the motorcycle is prevented.

A description will hereinafter be made on a controller and a control method according to the invention by using the drawings. Note that a description will hereinafter be made on a case where a motorcycle is a two-wheeled motor vehicle; however, the motorcycle may be another motorcycle such as a three-wheeled motor vehicle. In addition, a 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; however, at least one of the front-wheel brake mechanism and the rear-wheel brake mechanism may be provided in multiple units.

A configuration, an operation, and the like, which will be described below, constitute merely one example, and the controller and the control method according to the invention are not limited to a case with such a configuration, such an operation, 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. In addition, a detailed structure will appropriately be depicted in a simplified manner or will not be depicted.

A description will be made on a configuration of a brake system <NUM> according to an embodiment of the invention. <FIG> is a schematic view of an exemplary configuration of a motorcycle <NUM> on which a brake system <NUM> according to the embodiment of the invention is mounted. <FIG> is a schematic view of an exemplary configuration of the brake system <NUM> according to the embodiment of the invention. <FIG> is a block diagram of an exemplary functional configuration of a controller <NUM> according to the embodiment of the invention. <FIG> is a view illustrating a lean angle.

As depicted in <FIG> and <FIG>, the brake system <NUM> is mounted on the motorcycle <NUM>. The motorcycle <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 the freely turnable manner with the handlebar <NUM>; and a rear wheel <NUM> that is held by the trunk <NUM> in a freely rotatable manner.

For example, the brake system <NUM> includes: a first brake operation section <NUM>; a 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 a rear-wheel brake mechanism <NUM> that brakes the rear wheel <NUM> in the interlocking manner with at least the second brake operation section <NUM>.

The first brake operation section <NUM> is provided on the handlebar <NUM> and is operated by a driver's hand. The first brake operation section <NUM> is a brake lever, for example. The second brake operation section <NUM> is provided in a lower portion of the trunk <NUM> and is operated by the driver's foot. The second brake operation section <NUM> is a brake pedal, for example.

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 depicted) 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 depicted) ; a wheel cylinder <NUM> that is provided in the brake caliper <NUM>; a primary channel <NUM> through which brake fluid in the master cylinder <NUM> is delivered to 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 in 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 from 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. A first valve (USV) <NUM> is provided in a portion of the primary channel <NUM> that is between an end of the primary channel <NUM> on the master cylinder <NUM> side and a portion of the primary channel <NUM> to which a downstream end of the secondary channel <NUM> is connected. The supply channel <NUM> communicates between the master cylinder <NUM> and a suction side of the pump <NUM> in the secondary channel <NUM>. A second valve (HSV) <NUM> is provided in 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 the unenergized state and opened in the energized state, for example. The first valve <NUM> is an electromagnetic valve that is opened in the unenergized state and is closed in the energized state, for example. The second valve <NUM> is an electromagnetic valve that is closed in the unenergized state and is opened in the energized state, for example.

A hydraulic pressure control unit <NUM> is configured by including: members 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>; a base body <NUM> that is provided with those members and is formed with channels constituting the primary channels <NUM>, the secondary channels <NUM>, and the supply channels <NUM> therein; and the controller (ECU) <NUM>. In the brake system <NUM>, the hydraulic pressure control unit <NUM> is a unit that has a function of controlling a hydraulic pressure of the brake fluid in each of the wheel cylinders <NUM>, that is, a braking force to be applied to the front wheel <NUM> by the front-wheel brake mechanism <NUM> and a braking force to be applied to the rear wheel <NUM> by the rear-wheel brake mechanism <NUM>.

The members may collectively be provided in the single base body <NUM> or may separately be provided in the multiple base bodies <NUM>. In addition, the controller <NUM> may be provided as one unit or may be divided into multiple units. Furthermore, the controller <NUM> may be attached to the base body <NUM> or may be attached to a member other than the base body <NUM>. Moreover, the controller <NUM> may partially or entirely be constructed of a microcomputer, a microprocessor unit, or the like, may be constructed of a member in which firmware and the like can be updated, or may be a program module or the like that is executed by a command from a CPU or the like, for example.

In a normal state, that is, in a state where an automatic cruise deceleration operation, which will be described below, is not performed, 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 depicted) 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 depicted) of the brake caliper <NUM> is then pressed against a rotor 3a of the front wheel <NUM>, and the braking force is thereby applied to the front wheel <NUM>. Meanwhile, when the second brake operation section <NUM> is operated, in the rear-wheel brake mechanism <NUM>, the piston (not depicted) 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 depicted) of the brake caliper <NUM> is then pressed against a rotor 4a of the rear wheel <NUM>, and the braking force is thereby applied to the rear wheel <NUM>.

As depicted in <FIG> and <FIG>, the brake system <NUM> includes master-cylinder pressure sensors <NUM>, wheel-cylinder pressure sensors <NUM>, a front-wheel rotational frequency sensor <NUM>, a rear-wheel rotational frequency sensor <NUM>, a lean angle sensor <NUM>, a peripheral environment sensor <NUM>, a steering angle sensor <NUM>, and an input device <NUM>, for example. Each of the sensors and the input device <NUM> is communicable with the controller <NUM>.

Each of the master-cylinder pressure sensors <NUM> detects a hydraulic pressure of the brake fluid in the master cylinder <NUM> and outputs a detection result. Each of the master-cylinder pressure sensors <NUM> may detect another physical quantity that can substantially be converted to the hydraulic pressure of the brake fluid in the master cylinder <NUM>. The master-cylinder pressure sensor <NUM> is provided in each of the front-wheel brake mechanism <NUM> and the rear-wheel brake mechanism <NUM>.

Each of the wheel-cylinder pressure sensors <NUM> detects the hydraulic pressure of the brake fluid in the wheel cylinder <NUM> and outputs a detection result. Each of the wheel-cylinder pressure sensors <NUM> may detect another physical quantity that can substantially be converted to the hydraulic pressure of the brake fluid in the wheel cylinder <NUM>. The wheel-cylinder pressure sensor <NUM> is provided in each of the front-wheel brake mechanism <NUM> and the rear-wheel brake mechanism <NUM>.

The front-wheel rotational frequency sensor <NUM> detects a rotational frequency of the front wheel <NUM> 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 rear-wheel rotational frequency sensor <NUM> detects a rotational frequency of the rear wheel <NUM> 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 front-wheel rotational frequency sensor <NUM> and the rear-wheel rotational frequency sensor <NUM> are respectively provided on the front wheel <NUM> and the rear wheel <NUM>.

The lean angle sensor <NUM> detects a lean angle of the motorcycle <NUM> and an angular velocity of the lean angle thereof, and outputs a detection result. For example, the lean angle corresponds to a tilt angle θ of the motorcycle <NUM> in a rolling direction with respect to an upper vertical direction depicted in <FIG>. Note that the motorcycle <NUM> is tilted in the rolling direction with respect to the upper vertical direction during turning travel. More specifically, an inertial measurement unit (IMU) that includes a three-axis gyroscope sensor and a three-directional acceleration sensor is used as the lean angle sensor <NUM>. The lean angle sensor <NUM> may detect another physical quantity that can substantially be converted to the lean angle of the motorcycle <NUM> and the angular velocity of the lean angle thereof. The lean angle sensor <NUM> is provided in the trunk <NUM>.

The peripheral environment sensor <NUM> detects peripheral environment of the motorcycle <NUM> and outputs a detection result. For example, as the peripheral environment, the peripheral environment sensor <NUM> detects a distance from the motorcycle <NUM> to a preceding vehicle that travels ahead of the motorcycle <NUM>. The peripheral environment sensor <NUM> may detect another physical quantity that can substantially be converted to the distance from the motorcycle <NUM> to the preceding vehicle. More specifically, a camera that captures an image in front of the motorcycle <NUM> or a distance measurement sensor that can detect the distance from the motorcycle <NUM> to the preceding vehicle is used as the peripheral environment sensor <NUM>. The peripheral environment sensor <NUM> is provided in a front portion of the trunk <NUM>.

The steering angle sensor <NUM> detects a steering angle of the motorcycle <NUM> and an angular velocity of the steering angle thereof, and outputs a detection result. The steering angle sensor <NUM> may detect another physical quantity that can substantially be converted to the steering angle of the motorcycle <NUM> and the angular velocity of the steering angle thereof. The steering angle sensor <NUM> is provided on the handlebar <NUM>.

The input device <NUM> receives a travel mode selection operation by the driver and outputs information indicative of the received operation. As the travel mode, the input device <NUM> at least receives the selection operation in which an automatic cruise travel mode is selected. The automatic cruise travel mode is a travel mode in which the motorcycle <NUM> continues traveling with behavior thereof being at least partially controlled automatically. In the automatic cruise travel mode, for example, the motorcycle <NUM> is controlled that the distance therefrom to the preceding vehicle approximates a distance reference value. As the distance from the motorcycle <NUM> to the preceding vehicle, the distance reference value is set to such a value that the driver's safety can be secured. In the automatic cruise travel mode, the motorcycle <NUM> may be controlled that a body speed thereof approximates a speed reference value. For example, the speed reference value may appropriately be set by the driver. The body speed of the motorcycle <NUM> may be computed on the basis of the rotational frequencies of the front wheel <NUM> and the rear wheel <NUM>. For example, a lever, a button, or a touch panel may be used as the input device <NUM>. The input device <NUM> is provided on the handlebar <NUM>, for example.

The controller <NUM> controls the behavior of the motorcycle <NUM>. The controller <NUM> includes an acquisition section <NUM> and an execution section <NUM>, for example. The acquisition section <NUM> acquires the information that is output from each of the sensors and the input device <NUM>, and outputs the acquired information to the execution section <NUM>. The execution section <NUM> includes a control section <NUM>, a deceleration request determination section <NUM>, a change rate determination section <NUM>, and a lean angle determination section <NUM>, for example. Each of the determination sections executes determination processing by using the information that is output from each of the sensors. When the driver selects the automatic cruise travel mode, the execution section <NUM> initiates a control mode to make the motorcycle <NUM> perform the automatic cruise deceleration operation in accordance with a determination result by the deceleration request determination section <NUM>. In the control mode, the control section <NUM> outputs a command that governs the operations of the inlet valves <NUM>, the outlet valves <NUM>, the pumps <NUM>, the first valves <NUM>, the second valves <NUM>, and the like in accordance with the determination result by each of the determination sections, so as to control automatic deceleration that is deceleration of the motorcycle <NUM> generated by the automatic cruise deceleration operation.

More specifically, in the control mode, the control section <NUM> controls the automatic deceleration in accordance with the lean angle of the motorcycle <NUM>. In the control mode, the control section <NUM> may also control the automatic deceleration in accordance with a change rate of a state amount that is related to posture of the motorcycle <NUM> during the turning travel. Note that the control of the automatic deceleration includes control to permit or prohibit the automatic cruise deceleration operation in addition to the control of the automatic deceleration of the motorcycle <NUM> that is generated during the automatic cruise deceleration operation.

The controller <NUM> includes a storage element, and the information such as the reference values used in the processing executed by the controller <NUM> may be stored in the storage element in advance.

The automatic cruise travel mode includes an automatic cruise acceleration operation in which the motorcycle <NUM> is accelerated regardless of presence or absence of the operation by the driver. The automatic cruise acceleration operation is controlled by another controller that is a separate component from the controller <NUM> or is integrated with the controller <NUM>, for example. Automatic acceleration as acceleration of the motorcycle <NUM> that is generated during the automatic cruise acceleration operation may be controlled when the other controller controls engine output of the motorcycle <NUM>.

A description will be made on an operation of the brake system <NUM> according to the embodiment of the invention. <FIG> is a flowchart of an example of a processing procedure that is executed by the controller <NUM> according to the embodiment of the invention. A control flow depicted in <FIG> is repeated while the automatic cruise travel mode is selected. Step S110 and step S190 in <FIG> respectively correspond to initiation and termination of the control flow. In step S110, the control flow is initiated in a state where the control mode is not initiated.

In step S113, the deceleration request determination section <NUM> determines whether a deceleration request has been made. If it is determined that the deceleration request has been made (step S113/Yes), the processing proceeds to step S115. On the other hand, if it is determined that the deceleration request has not been made (step S113/No), step S113 is repeated. For example, in the case where the distance from the motorcycle <NUM> to the preceding vehicle falls below the distance reference value, the deceleration request determination section <NUM> determines that the deceleration request has been made. Note that, in the case where the motorcycle <NUM> is controlled in the automatic cruise travel mode such that the body speed thereof approximates the speed reference value, the deceleration request determination section <NUM> may determine that the deceleration request has been made when the body speed of the motorcycle <NUM> exceeds the speed reference value.

The above description has been made on the case where the deceleration request determination section <NUM> compares the distance from the motorcycle <NUM> to the preceding vehicle with the distance reference value or compares the body speed of the motorcycle <NUM> with the speed reference value. However, these comparisons may be made by the other controller that differs from the controller <NUM>. In such a case, the other controller outputs information indicative of results of these comparisons or information that directly indicates whether the deceleration request has been made to the controller <NUM>. In this way, the deceleration request determination section <NUM> can make the determination.

In step S115, the execution section <NUM> initiates the control mode to make the motorcycle <NUM> perform the automatic cruise deceleration operation.

Next, in step S117, the acquisition section <NUM> acquires the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel. The state amount that is related to the posture of the motorcycle <NUM> during the turning travel includes the lean angle, the angular velocity of the lean angle, the steering angle, or the angular velocity of the steering angle, for example.

Next, in step S119, the change rate determination section <NUM> determines whether the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel exceeds a change rate reference value. If it is determined that the change rate exceeds the change rate reference value (step S119/Yes), the processing proceeds to step S127. On the other hand, if it is determined that the change rate does not exceed the change rate reference value (step S119/No), the processing proceeds to step S121. The change rate reference value is set to such a value that a determination on whether the driver has his/her intention to avoid the preceding vehicle can be made.

In step S121, the acquisition section <NUM> acquires the lean angle of the motorcycle <NUM>.

Next, in step S123, the lean angle determination section <NUM> determines whether the lean angle of the motorcycle <NUM> exceeds a lean angle reference value. If it is determined that the lean angle exceeds the lean angle reference value (step S123/Yes), the processing proceeds to step S127. On the other hand, if it is determined that the lean angle does not exceed the lean angle reference value (step S123/No), the processing proceeds to step S125. The lean angle reference value is such a value that a determination on whether a possibility of falling of the motorcycle <NUM>, which is resulted from generation of the deceleration of the motorcycle <NUM>, is excessively high can be made, and is set in accordance with a friction coefficient of a travel road surface, a design specification of the motorcycle <NUM>, or the like, for example.

In step S125, the control section <NUM> permits the automatic cruise deceleration operation. Once permitting the automatic cruise deceleration operation, the control section <NUM> causes the generation of the automatic deceleration that is the deceleration irrespective of the driver's operation, and makes the motorcycle <NUM> perform the automatic cruise deceleration operation. For example, the control section <NUM> causes the generation of the automatic deceleration through generation of the braking force that is applied to the wheel by at least one of the front-wheel brake mechanism <NUM> and the rear-wheel brake mechanism <NUM>. More specifically, the control section <NUM> drives the pump <NUM> in 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, so as to cause the generation of the braking force that is applied to the wheel.

The control section <NUM> controls a rotational frequency of the pump <NUM> and thereby controls the braking force that is applied to the wheel. More specifically, the control section <NUM> computes reference target deceleration that is a reference value of a target value of the automatic deceleration. For example, as a difference between the distance from the motorcycle <NUM> to the preceding vehicle and the distance reference value is increased (in other words, as the motorcycle <NUM> comes closer to the preceding vehicle), the control section <NUM> computes a high value as the reference target deceleration. Here, the control section <NUM> may compute a constant value as the reference target deceleration irrespective of a magnitude of the difference between the distance from the motorcycle <NUM> to the preceding vehicle and the distance reference value. Then, the control section <NUM> decides target deceleration on the basis of the computed reference target deceleration. For example, the control section <NUM> decides a value that is acquired by multiplying the reference target deceleration by a coefficient as the target deceleration. Next, based on the target deceleration, the control section <NUM> decides a target hydraulic pressure that is a target value of the hydraulic pressure of the brake fluid in the wheel cylinder <NUM>. Then, the control section <NUM> controls the rotational frequency of the pump <NUM> such that the hydraulic pressure of the brake fluid in the wheel cylinder <NUM> matches the target hydraulic pressure. In this way, the automatic deceleration is controlled to match the target deceleration.

In the case where the motorcycle <NUM> is controlled in the automatic cruise travel mode such that the body speed thereof approximates the speed reference value, the control section <NUM> computes the higher value as the reference target deceleration as a difference between the body speed of the motorcycle <NUM> and the speed reference value is increased, for example. Here, the control section <NUM> may compute a constant value as the reference target deceleration irrespective of a magnitude of the difference between the body speed of the motorcycle <NUM> and the speed reference value.

The above description has been made on the case where the control section <NUM> computes the reference target deceleration. However, the other controller that differs from the controller <NUM> may compute the reference target deceleration. In such a case, the other controller outputs information indicative of the reference target deceleration to the controller <NUM>. In this way, the control of the automatic deceleration by the control section <NUM> can be realized.

For example, in the case where the lean angle is large, the control section <NUM> makes the motorcycle <NUM> perform the automatic cruise deceleration operation in which the automatic deceleration is lower than the automatic deceleration in the automatic cruise deceleration operation that is performed when the lean angle is small. More specifically, the control section <NUM> decides the value that is acquired by multiplying the reference target deceleration by the coefficient as the target deceleration, and the coefficient becomes smaller as the lean angle is increased. In this way, the control section <NUM> controls the automatic deceleration.

Alternatively, for example, in the case where the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel is high, the control section <NUM> makes the motorcycle <NUM> perform the automatic cruise deceleration operation, and the automatic deceleration therein is lower than the automatic deceleration in the automatic cruise deceleration operation that is performed when the change rate is low. More specifically, the control section <NUM> decides the value that is acquired by multiplying the reference target deceleration by the coefficient as the target deceleration, and the coefficient becomes smaller as the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel is increased. In this way, the control section <NUM> controls the automatic deceleration.

The control section <NUM> may decide the target deceleration in accordance with both of the lean angle and the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel. In such a case, the control section <NUM> multiplies the reference target deceleration by both of the coefficient corresponding to the lean angle and the coefficient corresponding to the change rate of the state amount, and decides the acquired value as the target deceleration, for example.

Note that the above description has been made on the case where the control section <NUM> controls the automatic deceleration by controlling the braking force that is applied to the wheel. However, the control section <NUM> may control the automatic deceleration by controlling the engine output of the motorcycle <NUM>. More specifically, the control section <NUM> may control the automatic deceleration by using an operational effect of engine brake that is exerted when the engine output is lowered. Alternatively, the control section <NUM> may control the automatic deceleration by controlling both of the braking force that is applied to the wheel and the engine output.

In step S127, the control section <NUM> prohibits the automatic cruise deceleration operation. When prohibiting the automatic cruise deceleration operation, the control section <NUM> brings the motorcycle <NUM> into the normal state where the deceleration is generated in accordance with the driver's operation. More specifically, the control section <NUM> brings the motorcycle <NUM> into a state where the inlet valves <NUM> are opened, the outlet valves <NUM> are closed, the first valves <NUM> are opened, and the second valves <NUM> are closed, so as to prohibit driving of the pumps <NUM>.

Following step S125 or step S127, in step S131, the deceleration request determination section <NUM> determines whether the deceleration request has been made. If it is determined that the deceleration request has been made (step S131/Yes), the processing returns to step S117. On the other hand, if it is determined that the deceleration request has not been made (step S131/No), the processing proceeds to step S133.

As described above, if it is determined in step S131 that the deceleration request has been made (step S131/Yes), the control mode continues, and the processing from step S117 to step S131 is repeated. In the case where the control mode continues, the control section <NUM> appropriately switches between a state where the automatic cruise deceleration operation is permitted and a state where the automatic cruise deceleration operation is prohibited in accordance with determination results of the determination processing by the change rate determination section <NUM> and the lean angle determination section <NUM> (step S119 and step S123).

In the case where the determination results in step S119 and step S123 are No in the state where the automatic cruise deceleration operation is permitted, the control section <NUM> continues the state where the automatic cruise deceleration operation is permitted. In this case, for example, the control section <NUM> controls the automatic deceleration of the motorcycle <NUM>, which is generated during the automatic cruise deceleration operation, in accordance with the lean angle that is acquired during the automatic cruise deceleration operation. In addition, for example, the control section <NUM> controls the automatic deceleration of the motorcycle <NUM>, which is generated during the automatic cruise deceleration operation, in accordance with the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel and that is acquired during the automatic cruise deceleration operation.

In the case where at least one of the determination results in step S119 and step S123 is Yes in the state where the automatic cruise deceleration operation is permitted, the control section <NUM> cancels the state where the automatic cruise deceleration operation is permitted, and prohibits the automatic cruise deceleration operation. For example, in the case where the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel and that is acquired during the automatic cruise deceleration operation exceeds the change rate reference value, the control section <NUM> cancels the state where the automatic cruise deceleration operation is permitted, and prohibits the automatic cruise deceleration operation. In addition, for example, in the case where the lean angle that is acquired during the automatic cruise deceleration operation exceeds the lean angle reference value, the control section <NUM> cancels the state where the automatic cruise deceleration operation is permitted, and prohibits the automatic cruise deceleration operation.

In the case where at least one of the determination results in step S119 and step S123 is Yes in the state where the automatic cruise deceleration operation is prohibited, the control section <NUM> continues the state where the automatic cruise deceleration operation is prohibited.

In the case where the determination results in step S119 and step S123 are No in the state where the automatic cruise deceleration operation is prohibited, the control section <NUM> cancels the state where the automatic cruise deceleration operation is prohibited, and permits the automatic cruise deceleration operation. For example, in the cases where the determination result in step S119 is No and the lean angle that is acquired during prohibition of the automatic cruise deceleration operation falls below the lean angle reference value, the control section <NUM> cancels the state where the automatic cruise deceleration operation is prohibited, and permits the automatic cruise deceleration operation. Note that the determination processing in step S119 may be eliminated from the control flow depicted in <FIG>. In such a case, in the case where the lean angle that is acquired during the prohibition of the automatic cruise deceleration operation falls below the lean angle reference value, the control section <NUM> cancels the state where the automatic cruise deceleration operation is prohibited, and permits the automatic cruise deceleration operation.

In step S133, the execution section <NUM> terminates the control mode.

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

In the brake system <NUM>, the automatic deceleration is controlled in accordance with the lean angle of the motorcycle <NUM> in the control mode in which the motorcycle <NUM> performs the automatic cruise deceleration operation. In this way, the automatic deceleration can appropriately be controlled in accordance with the posture of the motorcycle <NUM>. Therefore, the operation by the driver can appropriately be assisted while falling of the motorcycle <NUM> is prevented.

Preferably, in the control mode, in the case where the lean angle is large, the brake system <NUM> performs the automatic cruise deceleration operation, and the automatic deceleration therein is lower than the automatic deceleration in the automatic cruise deceleration operation that is performed when the lean angle is small. Here, grounding areas of tires of the motorcycle <NUM> are reduced as the lean angle is increased. In addition, a friction characteristic in a grounding portion of each of the tires of the motorcycle <NUM> possibly has such a characteristic that a friction force is less likely to be generated in an advancing direction as the lean angle is increased. Accordingly, the possibility of falling of the motorcycle <NUM>, which is resulted from the generation of the deceleration of the motorcycle <NUM>, tends to be increased as the lean angle is increased. Thus, in the case where the lean angle is large, the automatic cruise deceleration operation is performed, and the automatic deceleration therein is lower than the automatic deceleration in the automatic cruise deceleration operation that is performed when the lean angle is small. In this way, falling of the motorcycle <NUM> can effectively be prevented.

Preferably, in the control mode, the brake system <NUM> controls the automatic deceleration of the motorcycle <NUM>, which is generated during the automatic cruise deceleration operation, in accordance with the lean angle that is acquired during the automatic cruise deceleration operation. In this way, the automatic deceleration of the motorcycle <NUM>, which is generated during the automatic cruise deceleration operation, can appropriately be controlled in accordance with a change in the lean angle over time during the automatic cruise deceleration operation. For example, the automatic deceleration can be increased along with a decrease in the lean angle that is resulted from the automatic cruise deceleration operation. Therefore, an effect of appropriately assisting with the operation by the driver can be enhanced while falling of the motorcycle <NUM> is prevented.

According to the invention, in the control mode, the brake system <NUM> prohibits the automatic cruise deceleration operation in the case where the lean angle exceeds the lean angle reference value. In this way, in the case where the possibility of falling of the motorcycle <NUM>, which is resulted from the generation of the deceleration of the motorcycle <NUM>, is excessively high, the automatic cruise deceleration operation can be prohibited. Therefore, falling of the motorcycle <NUM> can effectively be prevented.

Preferably, in the control mode, the brake system <NUM> permits the automatic cruise deceleration operation in the case where the lean angle that is acquired during the prohibition of the automatic cruise deceleration operation falls below the lean angle reference value. In this way, in the case where the possibility of falling of the motorcycle <NUM>, which is resulted from the generation of the deceleration of the motorcycle <NUM>, becomes relatively low even during the prohibition of the automatic cruise deceleration operation, the automatic cruise deceleration operation can appropriately be performed. Therefore, the effect of appropriately assisting with the operation by the driver can be enhanced.

Preferably, in the control mode, the brake system <NUM> controls the automatic deceleration in accordance with the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel. In this way, the automatic deceleration can further appropriately be controlled in accordance with the posture of the motorcycle <NUM>. Therefore, the effect of appropriately assisting with the operation by the driver can further be enhanced while falling of the motorcycle <NUM> is prevented.

Preferably, in the control mode, the brake system <NUM> prohibits the automatic cruise deceleration operation in the case where the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel exceeds the change rate reference value. In this way, in the case where it is assumed that the driver has his/her intention to avoid the preceding vehicle, the automatic cruise deceleration operation can be prohibited. Thus, the generation of the automatic deceleration against the driver's intention can be prevented. Therefore, falling of the motorcycle <NUM> can effectively be prevented.

Note that, in the control mode, the control section <NUM> may prohibit the automatic cruise deceleration operation in the case where an operation amount of the motorcycle <NUM> by the driver exceeds an operation amount reference value. The operation of the motorcycle <NUM> by the driver includes an accelerator pedal operation, a brake operation, and a clutch operation, for example. The operation amount reference value is set to such a value that a determination on whether the driver has operated the motorcycle <NUM> can be made. Accordingly, in the case where the operation amount exceeds the operation amount reference value, the automatic cruise deceleration operation is prohibited. In this way, the generation of the automatic deceleration against the operation of the motorcycle <NUM> by the driver can be prevented. Therefore, falling of the motorcycle <NUM> can effectively be prevented.

In addition, in the control mode, in the case where the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel exceeds the change rate reference value, the control section <NUM> may reduce the operation amount reference value in comparison with the case where the change rate does not exceed the change rate reference value. In this way, in the case where it is assumed that the driver has his/her intention to avoid the preceding vehicle, sensitivity to detection of the operation of the motorcycle <NUM> by the driver can be improved. Therefore, the automatic cruise deceleration operation can further reliably be prohibited.

Preferably, in the control mode, in the case where the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel is high, the brake system <NUM> performs the automatic cruise deceleration operation, and the automatic deceleration therein is lower than the automatic deceleration in the automatic cruise deceleration operation that is performed when the change rate is low. Here, it is assumed that the possibility of the driver having his/her intention to avoid the preceding vehicle is higher as the change rate of the state amount is increased. Accordingly, in the case where the change rate of the state amount is high, the automatic cruise deceleration operation is performed, and the automatic deceleration therein is lower than the automatic deceleration in the automatic cruise deceleration operation that is performed when the change rate is low. In this way, the automatic deceleration can appropriately be controlled in accordance with the possibility of driver having his/her intention to avoid the preceding vehicle. Therefore, falling of the motorcycle <NUM>, which is resulted from the generation of the automatic deceleration against the driver's intention, can be prevented.

Preferably, in the control mode, the automatic deceleration of the motorcycle <NUM>, which is generated during the automatic cruise deceleration operation, is controlled in the brake system <NUM> in accordance with the change rate of the state amount that is related to the posture of the motorcycle <NUM> during the turning travel and that is acquired during the automatic cruise deceleration operation. In this way, the automatic deceleration of the motorcycle <NUM>, which is generated during the automatic cruise deceleration operation, can appropriately be controlled in accordance with a change in the change rate of the state amount over time during the automatic cruise deceleration operation. Therefore, falling of the motorcycle <NUM>, which is resulted from the generation of the automatic deceleration against the driver's intention, can effectively be prevented.

Claim 1:
A controller (<NUM>) for controlling behavior of a motorcycle (<NUM>), the controller (<NUM>) comprising:
an acquisition section (<NUM>) configured to acquire a lean angle of the motorcycle (<NUM>); and
an execution section (<NUM>) configured to initiate a control mode to make the motorcycle (<NUM>) perform an automatic cruise deceleration operation, in the case where a distance from the motorcycle (<NUM>) to a preceding vehicle falls below a distance reference value, or in the case where a body speed of the motorcycle (<NUM>) exceeds a speed reference value, wherein the execution section (<NUM>) includes a control esction (<NUM>) and in the control mode, the control esction (<NUM>) is configured to control automatic deceleration that is deceleration of the motorcycle (<NUM>) generated by the automatic cruise deceleration operation is controlled in accordance with the lean angle, and
in the control mode, in the case where the lean angle exceeds a lean angle reference value, the automatic cruise deceleration operation is prohibited.