Abstract: A control input for operating an actual vehicle actuator and a control input for operating a vehicle model are determined by an FB distribution law based on a difference between a reference state amount determined by a vehicle model and an actual state amount of an actual vehicle such that the state amount error is approximated to zero, and then an actuator device of the actual vehicle and the model vehicle are operated based on the control inputs. The FB distribution law determines a control input for operating the model such that a state amount error is approximated to zero while restraining a predetermined restriction object amount from deviating from a permissible range. A vehicle control device capable of enhancing robustness against disturbance factors or their changes while performing operation control of actuators that is as suited to behaviors of an actual vehicle as possible is provided.

Abstract: A control input for operating an actual vehicle actuator and a control input for operating a vehicle model are determined by an FB distribution law based on a difference between a reference state amount determined by a vehicle model and an actual state amount of an actual vehicle such that the state amount error is approximated to zero, and then an actuator device of the actual vehicle and the model vehicle are operated based on the control inputs. The FB distribution law determines a control input for operating the model such that a state amount error is approximated to zero while restraining a predetermined restriction object amount from deviating from a permissible range. A vehicle control device capable of enhancing robustness against disturbance factors or their changes while performing operation control of actuators that is as suited to behaviors of an actual vehicle as possible is provided.

Abstract: A cockpit is supported by a motion base in a state of being capable of making swinging movement. A host computer calculate vehicle motion information in accordance with operation of various operation equipments performed by a driver accommodated in the cockpit. A simulation image is formed, the cockpit is controlled for swinging movement, and various meters or the like in the cockpit are controlled on the basis of an obtained result of the calculation. Thus, the drive simulation is carried out in a state approximate to that of a real vehicle.

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.

Abstract: When a steady straight advancing state presuming device presumes that the vehicle is in a steady straight advancing state, and a slip rate calculating device calculates a small slip rate, based on an output from a driving-state detecting device, or when the steady straight advancing state presuming device presumes that the vehicle is in the steady straight advancing state, and a driven wheel torque calculating device calculates a small driven wheel torque, based on the output from the driving-state detecting device, a correction execution determining device determines that the vehicle is in a stable state suitable for correcting the wheel speed. By a command from the correction execution determining device, a correcting device corrects the driven wheel speed or the follower wheel speed based on a speed ratio of the driven wheel speed to the follower wheel speed calculated by a speed ratio calculating device.

Abstract: A technique to indicate a different-diameter wheel such as a temporary tire and to accurately correct the wheel speed of the different-diameter wheel is determined. Wheel speeds of a pair of left and right driven wheels are detected by wheel speed sensors and wheel speeds of a pair of left and right follower wheels are detected by wheel speed sensors. Yaw rates are calculated from the wheel speeds of the left and right wheels, and yaw rates are calculated from the wheel speeds of the wheels located diagonally. Which wheel of the four wheels is a different-diameter wheel is determined based on the magnitudes of the four yaw rates and the wheel speed of the different-diameter wheel is corrected based on a ratio in wheel speed between the different-diameter wheel and the other wheels.

Abstract: A first longitudinal grip force FGG is calculated by differentiating a vehicle body speed by time. A driven wheel torque is calculated from an engine torque and a second longitudinal grip force FGT is calculated from the driven wheel torque. The first longitudinal grip force FGG and the second longitudinal grip force FGT are compared with each other, and the higher one of such grip force is selected as a longitudinal grip force TG. When the vehicle travels on a normal flat road, the first longitudinal grip force FGG obtained from the vehicle body speed is selected. But when the vehicle travels on an ascent road, on which the first longitudinal grip does not indicate an accurate value, the second longitudinal grip force FGT obtained from the engine torque is selected. With this arrangement, the longitudinal grip force is accurately estimated even if the vehicle travels on such an ascent road.

Abstract: The rotational speed difference between rotational speeds of front and rear road wheels of a motor vehicle is weighted by a first ratio, and the difference between the rotational speed difference between rotational speeds of front left and right road wheels and an average signal of reference steering angle or between the rotational speed difference between rotational speeds of rear left and right road wheels and the average signal of reference steering angle is weighted by a second ratio. A sum signal representative of the sum of the rotational speed difference weighted by the first ratio and the difference weighted by the second ratio is used to determine a pneumatic tire pressure reduction highly accurately even when running conditions of the motor vehicle change such as when the motor vehicle makes a turn.

Abstract: A system is provided to prevent suspension judder from being generated at the start of a vehicle which includes a traction control system. If the starting of the vehicle is detected based on driving-wheel speeds RL and RR, a shift position and an accelerator opening degree .theta.th1, an initial torque TQ2 and a delay time are map-searched based on the accelerator opening degree .theta.th1 and a steering angle .theta.st. The driving force for driven wheels is limited to the initial torque TQ2, until a delay time from the starting of the vehicle has elapsed, to prevent the generation of suspension judder. When the delay time has elapsed, an accelerating increment torque TQ3 is map-searched based on the accelerator opening degree .theta.th1 and the steering angle .theta.st, and is added to the initial torque TQ2, thereby ensuring the accelerating performance of the vehicle.

Abstract: A method for determining the fully-closed state of a subsidiary throttle valve. If a stable state judging circuit judges that there is no outside influence exerted on the operational state of the engine (a state in which the vehicle is stopped and the engine is in an idling state) even if the subsidiary throttle valve is fully closed, a valve closing circuit closes the subsidiary throttle valve and a fully-closed state determination is carried out. If the opening degree of the subsidiary throttle valve or the engine revolution number is largely varied during the determination process of the fully-closed state determination circuit, a valve-closing inhibiting circuit inhibits the closing of the subsidiary throttle valve to discontinue the determination.

Abstract: A traction control system for a vehicle includes a calculator for calculating a speed of a driven wheel of the vehicle, a calculator for calculating a vehicle speed and a calculator for calculating a slip rate of the driven wheel on the basis of the driven wheel speed and the vehicle speed, such that the feed-back control of a throttle valve is carried out to reduce the output torque from an engine to inhibit the excessive slipping of the driven wheel, when the slip rate exceeds a predetermined threshold value. The system further includes a calculator for calculating a total grip force of the vehicle, a calculator for calculating an initial engine required torque at the start of the feed-back control of the throttle valve on the basis of the total grip force, and a calculator for calculating an initial throttle opening degree of the throttle valve on the basis of the initial engine required torque.

Abstract: A subtractor calculates an actual wheel speed difference between rotational speeds of left and right wheels on a motor vehicle, and a steering angle converter calculates an actual steering angle from the actual wheel speed difference. The difference between the actual steering angle and an adequate steering angle which is produced based on a lateral acceleration is compared with a predetermined reference range. If the difference between the actual and adequate steering angles exceeds the predetermined reference range, then the pneumatic pressure of a tire on one of the left and right wheels is determined as being lowered. In the steering angle converter, a weight value is established according to a running condition of the motor vehicle, and the calculated actual steering angle or comparative sensitivity is varied according to the weight value.