Honda Giken Kogyo Kabushiki Kaisha

Honda Motor Co., Ltd.

Keiyu Kin

Shuji Shiraishi

Osamu Yano

Hiroyuki Urabe

Yoshimitsu Akuta

Osamu Yamamoto

Yuji Sakaki

Makoto Sato

Hiromi Inagaki

Mitsuya Serizawa

Yoshihiro Iwagawa

Fumikage Yamanaka

Wataru Saito

Yutaka Kichima

Makoto Taniguchi

Jun Miyakawa

Takeshi Nishihara

A vehicle C is provided with four wheel speed sensors VS (VSfl, VSfr, VSrl, VSrr) (wheel vibration detection means) for detecting wheel speed V (Vfl, Vfr, Vrl, Vrr) at respective four wheels W (left and right front wheels Wfl, Wfr and left and right rear wheels Wrl, Wrr). When the tire pressure is in the normal value, a tire pressure monitoring systemprepares vibration frequency reference spectrum data for predetermined vehicle speed bands based on the detection values of each wheel speed sensor VS. The tire pressure monitoring systemcompares the current vibration frequency spectrum data and the vibration frequency reference spectrum data corresponding to the current vehicle speed band, and determines that the tire is underinflated if the comparison result exceeds a predetermined value.

Tire pressure monitoring system

A radius of a corner is determined by using a corner radius calculating device based on road data and data related to position of a vehicle on the road. An actual turning radius when the vehicle enters the corner is estimated by an actual turning radius calculating device based on at least a vehicle speed and motion parameters of the vehicle, and the motion state of the vehicle is controlled by the motion state control device so that an actual turning radius of the vehicle becomes close to the radius of the corner based on a calculation by radius difference calculating device for calculating a difference between the calculated corner radius and the actual turning radius. Thus, a motion state of the vehicle at a time of traveling around the corner is properly controlled to enable the vehicle to pass the corner reliably.

Motion control apparatus for vehicle

A vehicle speed measuring apparatus includes front and rear wheel side vibration detection sensors for detecting vibrations from a road surface through tires, an input section through which the vibration detection sensors input their detection values, and a processing unit for calculating vehicle speed of the vehicle based on a change pattern of the detection values inputted. When the detection values are inputted through the input section, the processing unit feature extracts a change pattern of the detection values for the respective front and rear wheel sides by excluding inherent tire influences on the detection values, executes pattern matching between the front and rear wheel sides on the basis of the feature extracted change patterns of the detection values, and obtains a time difference from a coincidence of the change patterns, and thereafter calculates vehicle speed based on the time difference and a reference distance such as a wheel base.

Vehicle speed measuring apparatus

A rotational speed Vof a left front wheel T, a rotational speed Vof a right front wheel T, a rotational speed Vof a left rear wheel T, and a rotational speed Vof a right rear wheel Tare detected by rotational speed sensors S-S, respectively. A front-wheel yaw rate &#x3b3;F arising due to a rotational speed difference between the front wheels T, Tand a rear-wheel yaw rate &#x3b3;R arising due to a rotational speed difference between the rear wheels T, Tare monitored. When a significant disparity between the both rotational speed differences is observed, it is determined that tire inflation pressure of any of the wheels T-Thas decreased. Upon detection, correction is made to an apparent yaw rate that would be observed in the properly inflated wheel as a result of steering for correction by a driver, thereby improving detection accuracy of underinflation of the tires.

Underinflation detector

A four-wheel vehicle is equipped with rotational speed sensors S -S that detect a rotational speed V of a left front wheel T , a rotational speed V of a right front wheel T , a rotational speed V of a left rear wheel T and a rotational speed V of a right rear wheel T , respectively, and a yaw rate sensor S&ggr; that detects a yaw rate of the vehicle. An underinflation detector includes a controller that calculates a front-wheel yaw rate &ggr;F derived from a difference in rotational speed between the front wheels T , T , a rear-wheel yaw rate &ggr;R derived from a difference in rotational speed between the rear wheels T , T , and deviations of the yaw rates &ggr;F, &ggr;R from an actually measured value output from the yaw rate sensor S&ggr;. A rate of change of the deviation with respect to change of vehicle speed is determined to thereby detect insufficiency of inflation pressure of tires with high reliability. Utilizing this underinflation detector , the outputs of the yaw rate sensor S&ggr; can be corrected.

Underinflation detector and method of correcting output of sensor using the same

In a vehicle motion control system based on a target yaw rate scheme, a brake force computing unit brakes an outer front wheel in a controlled manner when a sign of the yaw rate has changed and the yaw rate increment has become equal to or greater than a threshold value after a counter steer action has been detected and the vehicle body slip angle has become equal to or greater than a threshold value. Thus, suppose that a vehicle travels a winding road and a counter steer action is taken. If the vehicle body slip angle and actual yaw rate increment exceed threshold values, the outer front wheel is braked. Therefore, even when the vehicle body slip angle reaches a maximum value and an attempt is made to reduce it again by a counter steer action in a similar manner as a swinging pendulum, because the increases in the yaw rate and actual yaw rate increment are predicted and monitored before the vehicle body slip angle reaches its maximum value, the vehicle is enabled to travel in a stable fashion.

Vehicle motion control system

In a system for computing a road surface frictional coefficient for controlling a motion of a vehicle, the road surface frictional coefficient is estimated according to the deviation of the estimated vehicle body fore-and-aft/lateral acceleration from the actually detected vehicle body fore-and-aft/lateral acceleration, instead of estimating it directly from the tire slip ratio so that the road surface frictional coefficient is prevented from being estimated substantially higher than it actually is. In particular, by judging a sudden change in the road surface frictional coefficient only when a change in the road surface frictional coefficient, in particular an increase in the frictional coefficient, has persisted for more than a prescribed time period, an error in the estimation of the road surface frictional coefficient can be minimized, and a favorable vehicle motion control based on the estimated road surface frictional coefficient can be ensured under all conditions.

System for computing a road surface frictional coefficient

An electrically operated parking brake apparatus that includes an electric motor and a screw mechanism The screw mechanism includes a screw-threaded shaft adapted to be rotationally driven by the electric motor, and a nut member meshing with the screw-threaded shaft, the nut member being movable along the screw-threaded shaft by the rotation of the screw-threaded shaft. The parking brake apparatus also includes a transmission member connected to the nut member for transmitting a brake operating force to a wheel brake, and a rotation preventing unit for preventing the rotation of the screw-threaded shaft so as to hold the brake operating force by fixing the position of the nut member relative to the screw-threaded shaft. The rotation preventing unit in one embodiment is an electromagnetic brake for confining the screw-threaded shaft to a stationary portion of a vehicle body.

Electrically operated parking brake apparatus

The turning behavior state of a vehicle is determined by a determining device, by comparing a front wheel slip angle and a rear wheel slip angle calculated based on a lateral slip angle of a vehicle body by a wheel slip angle calculating device, with a front wheel slip angle limit value and a rear wheel slip angle limit value which are determined based on a vehicle speed detected by a vehicle speed detecting device and a friction coefficient presumed by a friction coefficient presuming device. Thus, even in a state in which the road surface friction coefficient is low, the turning behavior state of the vehicle can be detected precisely.

Turning behavior state detecting system for vehicle

A travel state of a vehicle is detected by a travel-state detecting device. A lateral slip angle of a vehicle body is calculated as a first lateral slip angle in a first lateral slip angle calculating device by integrating a differentiated value of lateral slip angle determined based on a non-linear four-wheel vehicle's motion model. A lateral slip angle of the vehicle body is calculated as a second lateral slip angle in a second lateral slip angle calculating device by a calculation in a linear two-wheel vehicle's motion model. One of the first and second lateral slip angles is selected alternatively in a selecting device in accordance with the travel state detected by the travel-state detecting device such that the second lateral slip angle is selected when the travel-state detecting device detects a state in which the vehicle is traveling straightforwardly at a low speed. A slip angle of each of wheels is calculated by a slip angle calculating device based on the lateral slip angle selected in the selecting device. Thus, the lateral slip angle of the vehicle body can be calculated with good accuracy using an appropriate calculating equation depending on the travel state of the vehicle, and the wheel slip angle can be determined with good accuracy using the lateral slip angle of high accuracy.

Wheel slip angle detecting system for vehicle

A hydroplaning detection system comprising AM specific frequency component extraction AM, which comprises a band-pass filter for extracting signal components PS in a main frequency band corresponding to the wheel rotation speed or the vehicle speed from wheel rotation speed signals, and a band-pass filters for respectively extracting signal components PL in other frequency bands, and AM determining the occurrence of hydroplaning based on the ratio PL/PS between the signal components PS in the main frequency band and the signal components PL in other frequency bands.

Hydroplaning detector apparatus

An apparatus for detecting a wheel grip on a road has a wheel speed sensor for detecting a revolution speed of a wheel of a vehicle, a plurality of band-pass filters for filtering an output of the wheel speed sensor at a plurality of frequency bands, and a reference value memory device for storing in memory reference values dependent on the revolution speed of the wheel. The reference values are set for each of the frequency bands of the plurality of band-pass filters. The wheel grip on road is detected based on the correlation between that signal output for each of the frequency bands which is obtained through the band-pass filters and that reference value for each of the frequency bands which is stored in memory in the reference value memory device.

Apparatus for detecting wheel grip on road

A hydroplaning detecting system comprises wheel rotational speed detecting apparatus for detecting a wheel rotational speed of a wheel of a vehicle, reference pattern storage apparatus for previously storing a reference pattern of wheel rotational speed which varies over a period of time and is characteristic of hydroplaning generation, actual variation pattern extracting apparatus for extracting a actual variation in the wheel rotational speed over a period of time, and judgment apparatus for judging the matching between the reference pattern and the actual variation pattern. Thus, this hydroplaning detecting system is capable of accurately detecting the generation of hydroplaning.

Hydroplaning detecting system

A pneumatic tire pressure determining system on a motor vehicle detects an actual rotational speed difference between rotational speeds of front or rear left and right road wheels of the motor vehicle, detects an operating condition of the motor vehicle, and calculates an adequate rotational speed difference between rotational speeds of the front or rear left and right road wheels based on the detected operating condition of the motor vehicle. The system compares the adequate rotational speed difference and the actual rotational speed difference, and when the difference between the compared actual and adequate rotational speed differences exceeds a predetermined value, the system determines a pneumatic tire pressure reduction.

System for determining pneumatic tire pressure for motor vehicle by

A physical quantity control device includes first and second control elements having different sensitivities from one another, the first and second control elements providing outputs to change at least one physical quantity in response to first and second operational quantities individually input to the first and second control elements. First and second computing circuits are provided for computing the first and second operational quantities in response to a deviation between a predetermined target value and the physical quantity, wherein the physical quantity is feedback controlled to converge with the predetermined target value. Further, first and second filters for passing frequencies individually corresponding to the sensitivies of the first and second control elements, respectively, the first filter being provided in a feedback loop including the first control elements and the first computing circuit, and the second filter being provided in a second feedback loop including the second control element and the second computing circuit. Further, the output of the first and second control elements is preferably input to an operation means to generate the physical quantity, wherein the physical quantity controlled is a vehicle motion.

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Keiyu Kin