An embodiment system for monitoring a tire pressure includes a wheel speed sensor mounted on each wheel of a vehicle, a set button for resetting a pressure setting, and a controller configured to determine whether the tire pressure is low using the wheel speed sensor, output a low pressure warning, determine whether a user has an intention to reset the pressure setting when a manipulation of the set button is sensed after the low pressure warning is output, and reset the pressure setting in response to a response of the user.

A tire side device is provided with a vibration detection unit that outputs a detection signal corresponding to the magnitude of tire vibration, a control unit that performs to generate road surface data indicating a road surface condition that appears in the waveform of the detection signal, and a first data communication unit that transmits the road surface data. Furthermore, a vehicle body side system is provided with a second data communication unit that receives the road surface data transmitted from the first data communication unit, and a road surface determination unit that determines the condition of the road surface that the vehicle is traveling on the basis of the road surface data. In addition, sensing is performed by the control unit under different sensing conditions at the tire side device of at least one tire among a plurality of tires and the tire side device of at least one other tire among the plurality of tires, and road surface data generated on the basis of the different sensing conditions is transmitted from the first data communication unit.

A control unit of a tire-mounted sensor determines whether a tire has been exchanged. When the tire has been exchanged, the control unit changes the threshold value of a road surface state determination condition used for detecting the road surface state from vibration data of the tire detected by an acceleration sensor of the tire-mounted sensor. For example, the threshold value of the road surface state determination condition is reset upon determining that the tire has been exchanged, by transmitting an instruction to the tire-mounted sensor through a tool at an automobile maintenance shop, etc.

A method for estimating a condition of a tire is provided. The tire supports a vehicle and is mounted on a wheel. The wheel is rotatably mounted on an axle. A sensor is mounted on at least one of the tire, the wheel, the axle, and a component of the brake system. Vibrational data is measured with the sensor. The data from the sensor is transmitted to a processor, and the data is processed. The processed data is normalized and at least one of the normalized data and pre-processed data is input into a machine learning model. A condition estimation for the tire is generated, which includes at least one of a tread depth of the tire, a pressure of the tire, and a dual tire mismatch.

A method for efficiently estimating a degree of wear of a tire in which a normalized deformation speed index is set as a wear measure. The normalized deformation speed index is obtained by normalizing an index of a deformation speed near an edge of a tire contact patch, the index being calculated from magnitudes of peaks appearing in a radial acceleration waveform obtained by differentiating tire radial acceleration detected by an acceleration sensor. The degree of wear of the tire is estimated using using the wear measure, the ground contact time ratio, a worn tire approximate formula and an approximate formula when a tire is new, which have been obtained in advance and each represents a relationship between the wear measure and the ground contact time ratio obtained by running a plurality of tires having tire sizes different from each other.

A tire side device is provided with a vibration detection unit that outputs a detection signal corresponding to the magnitude of tire vibration, a control unit that performs to generate road surface data indicating a road surface condition that appears in the waveform of the detection signal, and a first data communication unit that transmits the road surface data. Furthermore, a vehicle body side system is provided with a second data communication unit that receives the road surface data transmitted from the first data communication unit, and a road surface determination unit that determines the condition of the road surface that the vehicle is traveling on the basis of the road surface data. In addition, sensing is performed by the control unit under different sensing conditions at the tire side device of at least one tire among a plurality of tires and the tire side device of at least one other tire among the plurality of tires, and road surface data generated on the basis of the different sensing conditions is transmitted from the first data communication unit.

A time series waveform of detected vibration of a tire during travel is multiplied by a window function of a prescribed time width and a time series waveform for each time window is extracted to calculate a feature vector from the time series waveform for each time window. Thereafter, when determining the state of the road surface during travel using the feature vector for each time window and road surface models, a plurality of the aforementioned road surface models is constructed depending on the magnitude of a braking/driving force, the braking/driving force acting on the aforementioned tire is estimated, and the state of the road surface is determined using the road surface models, which depend on the aforementioned feature vector and the magnitude of the estimated braking/driving force. The aforementioned road surface models are constructed with learning data comprising time series waveform data of tire vibration obtained by causing a vehicle mounted with a tire provided with an acceleration sensor to travel on road surfaces in multiple road surface states.

A method for ascertaining the instantaneous roadway roughness in a vehicle. In the method, the frequency-dependent amplitude response is determined from the wheel speed, and a roughness characteristic variable is ascertained as a measure of the roadway roughness.

A road surface state determination device includes a tire-side device and a vehicle-body-side system. The tire-side device is attached to each of a plurality of tires included in a vehicle. The vehicle-body-side system is included in a body of the vehicle. The tire-side device may output a detection signal corresponding to a magnitude of vibration of the tire. The tire-side device may sense the detection signal and generate road surface data indicative of a road surface state appearing in a waveform of the detection signal. The tire-side device may transmit the road surface data. The vehicle-body-side system may perform bidirectional communication with the tire-side device and receive the road surface data. The vehicle-body-side system may determine the road surface state of a road surface on which the vehicle is traveling based on the road surface data.

A road surface state estimation device includes a tire-side device and a vehicle-body-side system. The tire-side device is disposed in a tire. The vehicle-body-side system is disposed in a vehicle body. The tire-side device outputs a detection signal corresponding to a magnitude of vibration of the tire, generates road surface data based on the detection signal, and performs data communication with the vehicle-body-side system. The vehicle-body-side system acquires information related to the road surface state, performs the data communication with the tire-side device, transmits vehicle-body-side information indicating that the change in the road surface state occurs to the tire-side device when determining that a change in the road surface state occurs based on the information related to the road surface state, and estimates the road surface state based on the road surface data received by the second transceiver.