Techniques are described for determining weight distribution of a vehicle. A method of performing autonomous driving operation includes determining a vehicle weight distribution that values for each axle of the vehicle that describe weight or pressure applied on a respective axle. The values of the vehicle weight distribution are determined by removing at least one value that is outside a range of pre-determined values from a set of sensor values. The method further includes determining a driving-related operation of the vehicle weight distribution. For example, the driving-related operation may include determining a braking amount for each axle and/or determining a maximum steering angle to operate the vehicle. The method further includes controlling one or more subsystems in the vehicle via an instruction related to the driving-related operation. For example, transmitting the instruction to the one or more subsystems causes the vehicle to perform the driving-related operation.

A system and method are provided for estimating progression in vehicle tire wear. A tread depth is stored at a first (e.g., initial or unworn) stage for a given tire, along with a first set of modal frequencies for the tire. At a later (e.g., worn) stage, for example in concert with a controlled excitation of tire structural modes, a second set of corresponding modal frequencies are sensed for the tire, and a tire wear status of the tire is determined at the second stage based on a calculated frequency shift between at least one corresponding modal frequency from each of the first and second sets. In one example, an initial mass of the tire is stored, and a change in mass is calculated based on the calculated frequency shift. Alternatively, a correlation of modal frequency shift may be performed with respect to tread depth for a given tire.

Sensor systems using piezoresistive materials are described that may be integrated with vehicle tires for use in a variety applications such as, for example, tire pressure monitoring, tread wear monitoring, anti-lock braking system control, suspension adjustment and/or control, wheel-drive system control, or road surface determination.

The invention relates to an acceleration sensor, especially a duplex acceleration sensor, an arrangement and a method for detecting a loss of road grip of a vehicle wheel (3). The acceleration sensor comprises a tube (5) having a longitudinal axis forming a circular arc segment, and two closed ends. A mass (15; 315) is arranged inside the tube (5) such that is able to move inside the tube (5) in the longitudinal direction thereof. A magnet arrangement (17; 203; 205; 317) is designed to counteract, by way of a magnetic force exerted on the mass (15; 315), a movement of said mass (15; 315) from an idle position (25), and a read-out unit (608) is designed to detect a movement of said mass (15) from the idle position (25).

A rear wheel regenerative braking control system for vehicle, may include a brake controller; a vehicle controller; a hydraulic controller; and a motor controller, wherein the system and the method may maximize an amount of rear wheel regenerative braking while easily securing braking stability of a vehicle.

A wheel speed detection device includes a detection element, a base member, and an affixing member. The detection element has a main body, leads, and protruding from the main body. The affixing member affixes the detection element to the base member by pressing the leads and against the base member without pressing the main body against the base member

A method is provided for estimating a road surface condition by accurately determining whether or not there has been any large input to a tire without increasing the number of sensors. An acceleration sensor is disposed on the tire to detect the vibration of the tire in motion. The positions of leading end point and trailing end point of tire contact patch are estimated from the peak positions appearing in the time-variable waveform of the vibration. At the same time, the contact time, extra-contact time, and revolution time of the tire are calculated from the estimated positions of leading end point and trailing end point. Then using one or more of the calculated data, it is determined whether or not the estimated positions of leading end point and trailing end point are equal to the actual positions of leading end point and trailing end point. And if the result of the leading and trailing position determination is incorrect estimation, the estimation of a road surface condition is not performed.

The present invention provides a graded braking control device and control method for vehicle tire burst, and belongs to the technical field of vehicles. It solves the problems of rear-end collision and more instability of the vehicle resulting from emergency brake after vehicle tire burst. The device includes a tire pressure sensor, a controller, a radar sensor, a stability detection module and an ESC, wherein the radar sensor and the stability detection module are respectively connected with input ends of the controller, the tire pressure sensor is in wireless connection with the controller, and the ESC is connected with an output end of the controller. The control method includes: 1. monitoring vehicle tire condition; 2. carrying out traffic state assessment and determining a first maximum braking deceleration value for preventing the rear-end collision with the follower vehicle after emergency brake of the present vehicle; 3. carrying out tire burst vehicle stability state assessment in combination with the current speed and setting the maximum braking deceleration under stable state; and 4. carrying out tire burst graded braking. The device and the method can ensure quick and stable braking of the tire burst vehicle, and avoid the rear-end collision of the present vehicle with the follower vehicle.

A road surface condition estimation device extracts a detection signal of a vibration power generation element during a ground contact section to detect a road surface condition. A threshold used for determination of the ground contact section is variable according to a traveling speed of a vehicle. As a result, even if a pulse level of an output voltage of the vibration power generation element changes according to the traveling speed of the vehicle, the threshold corresponding to the change can be set. The ground contact section is determined with the use of the above thresholds, thereby being capable of performing the determination with high accuracy. Therefore, the road surface condition can be detected with high accuracy based on the ground contact section determined with high accuracy.

The invention relates to an acceleration sensor, especially a duplex acceleration sensor, an arrangement and a method for detecting a loss of road grip of a vehicle wheel (3). The acceleration sensor comprises a tube (5) having a longitudinal axis forming a circular arc segment, and two closed ends. A mass (15; 315) is arranged inside the tube (5) such that is able to move inside the tube (5) in the longitudinal direction thereof. A magnet arrangement (17; 203; 205; 317) is designed to counteract, by way of a magnetic force exerted on the mass (15; 315), a movement of said mass (15; 315) from an idle position (25), and a read-out unit (608) is designed to detect a movement of said mass (15) from the idle position (25).