Abstract: A road surface frictional coefficient estimating apparatus has a device for determining a first estimated value of a yaw moment Mnsp_estm generated at an NSP of a vehicle due to the resultant force of road surface reaction forces acting on each wheel by using, for example, a frictional coefficient estimated value that has been determined, and a device for determining a second estimated value of a yaw moment Mnsp_sens generated at the NSP from the observed value of motional state amounts defining an inertial force moment at the NSP. The increasing/decreasing manipulated variable of the frictional coefficient estimated value is sequentially determined on an error (Mnsp_sens?Mnsp_estm) such that the error is converged to zero, and the road surface frictional coefficient is updated on the basis of the increasing/decreasing manipulated variable.

Abstract: A road surface frictional coefficient estimating apparatus has a device for determining a first estimated value of a yaw moment Mnsp_estm generated at an NSP of a vehicle due to the resultant force of road surface reaction forces acting on each wheel by using, for example, a frictional coefficient estimated value that has been determined, and a device for determining a second estimated value of a yaw moment Mnsp_sens generated at the NSP from the observed value of motional state amounts defining an inertial force moment at the NSP. The increasing/decreasing manipulated variable of the frictional coefficient estimated value is sequentially determined on an error (Mnsp_sens?Mnsp_estm) such that the error is converged to zero, and the road surface frictional coefficient is updated on the basis of the increasing/decreasing manipulated variable.

Abstract: A picture display apparatus which has a control-data storage section which stores signal-processing control data generated by a control-data generating section, the stored data being related to an input terminal designated by an operating section, and which reads out signal-processing control data relating to another input terminal when the designated input terminal is switched to the other input terminal. When the signal-processing control data is generated by the control data generating section, signal processing is made in accordance with the generated signal-processing control data. When signal-processing control data is read out from the control-data storage section, the signal processing is made in accordance with the read-out signal-processing control data.

Abstract: A display apparatus is provided with a reverse gamma conversion circuit, an image signal processing circuit, and a display device. The display device is a PDP in which the light-emitting characteristics are linear. The image signal processing circuit is provided with a smoothing signal generator for smoothing image signals after reverse gamma conversion. Also provided is a detector whereby patterns that are to be processed as signals are detected from the image. The patterns include points of variation in which the gradation difference prior to reverse gamma conversion is a single gradation and in which the gradation difference is made to be two gradations or more due to reverse gamma conversion. A substitution unit is provided for substituting the smoothed gradation values in place of a portion of the gradation values of the pattern, and outputting the result to the display device.

Abstract: A rotational speed V1 of a left front wheel T1, a rotational speed V2 of a right front wheel T2, a rotational speed V3 of a left rear wheel T3, and a rotational speed V4 of a right rear wheel T4 are detected by rotational speed sensors S1-S4, respectively. A front-wheel yaw rate ?F arising due to a rotational speed difference between the front wheels T1, T2 and a rear-wheel yaw rate ?R arising due to a rotational speed difference between the rear wheels T3, T4 are 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 T1-T4 has 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.

Abstract: A four-wheel vehicle is equipped with rotational speed sensors S1-S4 that detect a rotational speed V1 of a left front wheel T1, a rotational speed V2 of a right front wheel T2, a rotational speed V3 of a left rear wheel T3 and a rotational speed V4 of a right rear wheel T4, respectively, and a yaw rate sensor S&ggr; that detects a yaw rate of the vehicle. An underinflation detector 1 includes a controller 2 that calculates a front-wheel yaw rate &ggr;F derived from a difference in rotational speed between the front wheels T1, T2, a rear-wheel yaw rate &ggr;R derived from a difference in rotational speed between the rear wheels T3, T4, 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.

Abstract: A rotational speed V1 of a left front wheel T1, a rotational speed V2 of a right front wheel T2, a rotational speed V3 of a left rear wheel T3, and a rotational speed V4 of a right rear wheel T4 are detected by rotational speed sensors S1-S4, respectively. A front-wheel yaw rate &ggr;F arising due to a rotational speed difference between the front wheels T1, T2 and a rear-wheel yaw rate &ggr;R arising due to a rotational speed difference between the rear wheels T3, T4 are 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 T1-T4 has 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.

Abstract: A four-wheel vehicle is equipped with rotational speed sensors S1-S4 that detect a rotational speed V1 of a left front wheel T1, a rotational speed V2 of a right front wheel T2, a rotational speed V3 of a left rear wheel T3 and a rotational speed V4 of a right rear wheel T4, respectively, and a yaw rate sensor S&ggr; that detects a yaw rate of the vehicle. An underinflation detector 1 includes a controller 2 that calculates a front-wheel yaw rate &ggr;F derived from a difference in rotational speed between the front wheels T1, T2, a rear-wheel yaw rate &ggr;R derived from a difference in rotational speed between the rear wheels T3, T4, 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A traction control system for a vehicle, which, during normal driving of the vehicle, if a driven wheel speed becomes less than a deceleration-control starting reference value which is set lower than a vehicle speed, a feed-back control of an opening degree of a throttle valve is started so as to converge the driven wheel speed into a target driven wheel speed. If a downshifting is conducted, the feed-back control of the throttle valve opening degree is feed-back controlled by using, in place of the driven wheel speed, a pseudo driven wheel speed calculated based on the number of revolutions of an engine and a gear position. With this arrangement, it is possible to open the throttle valve at an earlier stage to increase a driven wheel torque, and to avoid a deceleration slip at the time of downshifting at a high speed.

Abstract: A reduction in tire pressure in follower wheels and driven wheels is precisely determined irrespective of slipping states of the driven wheels through the use of apparatus wherein in a driven wheel slip amount calculating means M4 calculates a driven wheel slip amount KIDD as a left and right follower wheel speed difference FID and a left and right driven wheel speed difference RID; in a driven wheel torque calculating means M5, a driven wheel torque TQDW is calculated; in a driven wheel slip amount estimating means M6, a characteristic of variation in driven wheel slip amount KIDD relative to the variation in driven wheel torque TQDW is estimated using a least squares method; in a deviation calculating means M7, a deviation CKID between the follower wheel speed difference FID and the driven wheel speed difference RID in a state in which the driven wheels are not slipping, is calculated as an intercept of the driven wheel slip amount KIDD at a driven wheel torque equal to 0 (zero) in a graph of the variation

Abstract: A slip rate of the driven wheel is calculated (at step S1). When the slip rate is smaller and when the slip rate is larger (at steps S2 and S3), estimated road surface friction coefficients MUTG and MUFG are determined by searching a table, based on a total grip force TGS or a longitudinal grip force FG determined from a vehicle acceleration (at steps S4, S7, S5 and S9). The larger one of the estimated road surface friction coefficients MUTG and MUFG is selected as MUCON (at steps S10, S11 and S12). A minimum total grip force TGMIN determined by searching a table and based on MUCON is compared with the total grip force TGS determined from the vehicle acceleration (at step S13), and the larger one of the minimum total grip force TGMIN and total grip force TGS is delivered as a total grip force TG for traction control (at steps S14 and S15). Thus, it is possible to estimate a correct total grip force, taking the road surface friction coefficient into consideration.

Abstract: A wheel diameter judging system and wheel speed correcting system which calculates a driven wheel slip rate, and a driven wheel torque. A variation characteristic of the driven wheel slip rate relative to the variation in driven wheel torque is presumed using the method of least squares. A correction value corresponding to a ratio of the number of revolutions of a follower wheel to the number of revolutions of a driven wheel in a condition in which the driven wheel is not in a slipping state is calculated as an intercept of the driven wheel slip rate at the driving torque equal to zero in a graph of the variation characteristic. The driven wheel speed is corrected by the correction value. The driven wheel speed is corrected by the correction value. Thus, even if the driven wheel is in the slipping state, a difference in diameter between the follower and driven wheels can be accurately judged, and the follower wheel speed or the driven wheel speed can be accurately corrected.

Abstract: A reference value for a traction control is calculated based on a vehicle speed. When a vehicle is in a predetermined turning state, so that a driven wheel speed is equal to or lower than a predetermined value and a lateral acceleration is equal to or larger than a predetermined value, a correction value is searched from a table based on the vehicle speed and a steering angle to correct an error of the reference value generated due to a difference between the locus of the driven wheels and the locus of the follower wheels during turning of the vehicle. The reference value is corrected by subtracting the correction value from the reference value (when the vehicle is a rear wheel drive vehicle) or by adding the correction value to the reference value (when the vehicle is a front wheel drive vehicle. Thus, the reference value for the fraction control such as a reference value for a target slip rate can be accurately in accordance with the turning state of the vehicle.

Abstract: A reduction in pressure in tires fitted to follower wheels and driven wheels is precisely determined irrespective of slipping states of the driven wheels. A driven wheel slip rate calculating means M1 calculates driven wheel slip rates .lambda.L and .lambda.R. A driven wheel torque calculating means M2 calculates a driven wheel torque TQDW. A driven wheel slip rate estimating means M4 estimates a characteristic of variation in driven wheel slip rates .lambda.L and .lambda.R relative to the variation in driven wheel torque TQDW using a least squares method. A rotation-number ratio calculating means M5 calculates ratios CVWL and CVWR of the numbers of rotations of the follower wheels to the numbers of rotations of the driven wheels in a state in which the driven wheel torque in a graph of the variation characteristic is equal to zero.

Abstract: In a traction control system, an initial engine torque for a traction control is selected from the following engine torques: an engine torque calculated from a throttle opening degree and an engine revolution-number; a required engine torque calculated from a total acceleration and a vehicle speed; and an engine torque corresponding to a road surface of an extremely low friction coefficient, depending upon a slipping state determined by comparing a driven wheel speed with slip reference values. When the driven wheel speed repeatedly exceeds the slip reference value, it is determined that a hunting has been generated, and the engine torque corresponding to the road surface of the extremely low friction coefficient is selected, and the engine torque is largely reduced. Thus, when the friction coefficient of the road surface is low, the driven wheel speed is prevented from hunting.