An electronic tire maintenance system is provided for measuring a parameter of a device at a first location. The system includes a sensor for measuring the device parameter and generating a data signal representing the measured parameter. The system also includes a microprocessor coupled to the sensor for activating the sensor on a first periodic basis to measure the device parameter. The microprocessor includes a memory for storing the generated data signal representing the measured parameter. A transmitter and a receiver are coupled to the microprocessor. The microprocessor periodically partially awakens to determine, on a second periodic basis, if a received transmission is a valid interrogation signal and, if so, fully awakens and responds to the valid interrogation signal, via the transmitter, by at least transmitting the last stored measured parameter. In one embodiment, the device is a tire tag mounted inside a tire that measures tire data and transmits that data to a remote source in response to an interrogation request, an alert condition, or automatically on a periodic basis.

Electronic tire management system

A stabilizing observer-based control algorithm for an in-wheel-motored vehicle is proposed, which generates direct yaw moment to compensate for the state deviations. The control scheme is based on a fuzzy rule-based body slip angle (beta) observer. In the design strategy of the fuzzy observer, the vehicle dynamics is represented by Takagi-Sugeno-like fuzzy models. Initially, local equivalent vehicle models are built using the linear approximations of vehicle dynamics for low and high lateral acceleration operating regimes, respectively. The optimal beta observer is then designed for each local model using Kalman filter theory. Finally, local observers are combined to form the overall control system by using fuzzy rules. These fuzzy rules represent the qualitative relationships among the variables associated with the nonlinear and uncertain nature of vehicle dynamics, such as tire force saturation and the influence of road adherence. An adaptation mechanism for the fuzzy membership functions has been incorporated to improve the accuracy and performance of the system. The effectiveness of this design approach has been demonstrated in simulations and in a real-time experimental setting.

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Direct Yaw-Moment Control of an In-Wheel-Motored Electric Vehicle Based on Body Slip Angle Fuzzy Observer

A tire characteristic monitoring method allows automatic programming of tire position information in a remote tire pressure monitoring system (10). The method includes, from a remotely located exciter (16) using a primary coil (18) to transmit a relatively low frequency signal to a secondary coil (L1) of a tire monitor (12) associated with a tire of a vehicle. The method further includes the step of, at the tire monitor, in response to the relatively low frequency signal, transmitting a relatively high transmitting signal to convey data. The data are received at the exciter and subsequently loaded into a receiving unit (14) of the vehicle.

Method and apparatus for a remote tire pressure monitoring system

A vehicle stability enhancement control algorithm for a four-wheel-drive hybrid electric vehicle (HEV) is proposed using rear motor driving, regenerative braking control, and electrohydraulic brake (EHB) control. A fuzzy-rule-based control algorithm is proposed, which generates the direct yaw moment to compensate for the errors of the sideslip angle and yaw rate. Performance of the vehicle stability control algorithm is evaluated using ADAMS and MATLAB Simulink cosimulations. HEV chassis elements such as the tires, suspension system, and steering system are modeled to describe the vehicle's dynamic behavior in more detail using ADAMS, whereas HEV power train elements such as the engine, motor, battery, and transmission are modeled using MATLAB Simulink with the control algorithm. It is found from the simulation results that the driving and regenerative braking at the rear motor is able to provide improved stability. In addition, better performance can be achieved by applying the driving and regenerative braking control, as well as EHB control.

Vehicle Stability Enhancement of Four-Wheel-Drive Hybrid Electric Vehicle Using Rear Motor Control

Selected vehicle operational parameters such as tire pressure, wheel temperature and vibration are sensed by sensors mounted on wheel modules secured to the individual vehicle wheels. The sensed parameters are converted to digital format and the resulting digital data is manipulated to determine if the data falls within predetermined operating ranges. The data and information resulting from the manipulation are used to modulate an RF signal transmitted to another location on the vehicle. Additional parameters are sensed at the second location, and calculations are performed on the data received from the wheel modules and the data sensed at the second location to display operational, efficiency and safety information to the vehicle operator and to make such information available to others such as vehicle owners and maintenance personnel.

Vehicular data collection and transmission system and method

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.

System for determining pneumatic tire pressure for motor vehicle

To enhance both vehicle stability and steerability, vehicle dynamic parameters such as vehicle side slip angle, road friction coefficient and tire side forces were precisely estimated in real time. Utilizing four wheel slip control, a logic for optimizing vehicle dynamics was formulated. Tests on ice- and snow-covered roads demonstrated the effectiveness of the control, and confirmed the validity of the logic.

Enhancements in vehicle stability and steerability with slip control

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 characteristic; and in a wheel pressure-reduction determining means M8, a reduction in tire pressure is determined from a difference in diameter between the follower wheels and the driven wheels by comparing the deviation CKID with a reference value.

Wheel pressure-reduction determining system for vehicle

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 λL and λR. 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 λL and λR 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. A tire pressure-reduction determining means M6 then determines a reduction in pressure from a difference in diameter between the follower wheels and the driven wheels by comparing the rotation-number ratios CVWL and CVWR with a reference value.

Tyre pressure-reduction determining system for wheels of a vehicle

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.

Osamu Yano

Papers

System for determining pneumatic tire pressure for motor vehicle

Enhancements in vehicle stability and steerability with slip control

Wheel pressure-reduction determining system for vehicle

Tyre pressure-reduction determining system for wheels of a vehicle

Road surface frictional coefficient estimating apparatus