In a vehicle steering control system, an actuating torque is applied to steerable wheels according to a steering torque applied to a steering wheel in a conventional manner, and an additional actuating torque is applied to the steering wheel by an electric motor according to lateral dynamic conditions of the vehicle so as to control the lateral stability of the vehicle even in the presence of external interferences such as crosswind. Such external interferences are detected as a lateral dynamic condition of the vehicle such as the yaw rate of the vehicle, and the steering control system produces a steering reaction which counteracts such a lateral dynamic condition by applying the additional actuating torque to the steerable wheels so that the vehicle may maintain a straight course in spite of such external interferences without requiring any intentional efforts by the vehicle operator. In particular, by suppressing the additional actuating torque in an understeer condition, the handling of the vehicle can be improved.

Vehicle steering control system

The present invention relates to a vehicle recorder system that is configured with a video camera, a light weight memory system, and a radio communications facility suitable for use in conjunction with an moving vehicle. An automobile equipped with such video recorder system that is used throughout a day of service provides a video record of unusual events which may occur from time-to-time. For example, events such as accidents, near-misses, and excessive speed, among others, trigger a system to preserve video images collected before and after the moment of the event. Replaying these images provides information regarding the cause and true nature of the event. These systems are particularly suitable for vehicle fleets, or other groups of vehicles that can communicate with a common system.

Vehicle event recorder systems

A stability control system 24 for an automotive vehicle as includes a plurality of sensors 28-37 sensing the dynamic conditions of the vehicle and a controller 26 that controls a distributed brake pressure to reduce a tire moment so the net moment of the vehicle is counter to the roll direction. The sensors include a speed sensor 30 , a lateral acceleration sensor 32 , a roll rate sensor 34, and a yaw rate sensor 20. The controller 26 is coupled to the speed sensor 30, the lateral acceleration sensor 32, the roll rate sensor 34, the yaw rate sensor 28. The controller 26 determines a roll angle estimate in response to lateral acceleration, roll rate, vehicle speed, and yaw rate. The controller 26 changes a tire force vector using brake pressure distribution in response to the relative roll angle estimate.

Roll over stability control for an automotive vehicle

A method of on-demand energy delivery to an active suspension system comprising an actuator body, hydraulic pump, electric motor, plurality of sensors, energy storage facility, and controller is provided. The method comprises disposing an active suspension system in a vehicle between a wheel mount and a vehicle body, detecting a wheel event requiring control of the active suspension; and sourcing energy from the energy storage facility and delivering it to the electric motor in response to the wheel event.

Active vehicle suspension system

A vehicle steering system has a steering handle as well as steered vehicle wheels connected with one another with respect to the effect at least in the normal operation only by way of a control device ("steer by wire") which compares the signals of a steering angle actual value generator operated by the vehicle wheels and of a steering angle desired value generator operated by the handle The control device controls a motor used as a manual force adjuster which is coupled with the handle by way of a torsionally elastic shaft arrangement The extent of the torsionally elastic deformation is analyzed for determining the actual value of the manual force

Vehicle steering system

A suspension control system for automotive vehicles automatically adjusts the damping strength of variable shock absorbers or other dampers in accordance with road surface conditions as recognized by frequency analysis of a vehicle height or vibration sensor signal. The sensor signal reflects vertical displacement of the vehicle body from the road surface and includes high-frequency components due solely to displacement of the wheels or unsprung mass relative to the road surface and low-frequency components due to displacement of the vehicle body or sprung mass. The sensor signal is filtered into these separate frequency bands, the amplitude of each of which is compared to a corresponding reference level. The results of comparison give an indication of the degree and scale of irregularities in the road surface; specifically, a high-amplitude low-frequency component indicates larger-scale bumps and dips capable of bouncing the vehicle whereas a strong high-frequency component reflects a rough-textured road surface, such as gravel. The comparison information is sent to a suspension system controller which causes actuation of the shock absorbers to a stiffer mode of operation when the low-frequency sensor signal components are relatively strong.

Automotive suspension control system with road-condition-dependent damping characteristics

A system for estimating the state of a controlled vehicle's motion has a steering wheel angle sensor, a vehicle speed sensor, a sensor for sensing a first motion variable such as a yaw rate, a sensor for sensing a second motion variable such as a yaw acceleration, and a processing unit such as a microcomputer. In accordance with the sensor output signals, the processing unit produces a condition signal which is in a first signal state when the unit determines that the vehicle is in a steady-state turning motion, and in a second signal state when the unit determines that the vehicle is in a transient state turning motion. The processing unit determines estimated values of the first and second motion variables corresponding to the steering wheel angle and vehicle speed by solving a first predetermined mathematical vehicle model, and further determines an estimated value of a third motion variable such as slip angle or steer angle by solving a second mathematical vehicle model which may be identical to or different from the first model. The processing unit adjusts a value of a vehicle characterizing parameter such as a cornering power of the second model in accordance with the result of comparison between the sensed and estimated values of the first motion variable when the condition signal is in the first state, and in accordance with the result of comparison between the sensed and estimated value of the second motion variable when the condition signal is in the second state.

Vehicle motion estimating system

A control system for steering front wheels and rear wheels of a controlled vehicle has a processing unit such as a microcomputer which determines a desired value of at least one of dynamical variables such as yaw rate, yaw acceleration, and lateral acceleration from sensed steering input and sensed vehicle speed by solving equations of motion of a vehicle in which parameters inherent to the vehicle are set equal to desired values so determined as to provide desired cornering characteristics. From the desired value of the dynamical variable, the processing unit determines desired values of front and rear steering angles of the front and rear wheels required to achieve the desired value of the dynamical variable in the controlled vehicle. The control system further has a front wheel steering actuator for steering the front wheels in accordance with the desired value of the front steering angle, and a rear wheel steering actuator for steering the rear wheels in accordance with the desired value of the rear steering angle.

Steering control system for wheeled vehicle

A control system for a controlled vehicle has a steering wheel angle sensor, a vehicle speed sensor, a turning behavior sensor such as a side speed sensor and a yaw rate sensor, an actuator such as a hydraulic system for altering a rear wheel steer angle in accordance with a desired angle value, and a controller such as a microcomputer for determining the desired angle value by solving three distinct vehicle models. The controller first solves a reference model representing a desired vehicle to determine a desired vehicle response to the steering wheel angle and vehicle speed, and then solves a first actual model representing the actual controlled vehicle to determine the desired rear wheel steer angle value required to cause the controlled vehicle to produce the desired response. The controller further solves a second actual vehicle model representing the controlled vehicle to estimate the turning behavior resulting from the desired rear wheel steer angle, identifies front and rear wheel cornering powers of the second actual model by comparing the estimated and sensing turning behavior, and then adjusts the front and rear wheel cornering powers gradually in accordance with the result of the identification.

Model solving type vehicle steering control system with parameter identification

A vehicle steering control system has a steering wheel angle sensor, a vehicle speed sensor, a control unit and an actuator for steering either (or both) of front and rear wheel pairs of a controlled vehicle. The control unit determines desired values of yaw rate and lateral acceleration corresponding to the sensed steering wheel angle and vehicle speed by using at least one desired mathematical vehicle model having desired vehicle response characteristics. Then, the control unit determines a desired value of a front or rear wheel steer angle (or both of the front and rear wheel angles) theoretically required to achieve the desired value of the yaw rate, and another desired value of the steer angle theoretically required to achieve the desired value of the lateral acceleration. Finally, the control unit determines a weighted average of two desired values of the steer angle by using weights which are functions of vehicle speed and/or steering wheel angular speed. The actuator steers the front or rear wheel pair so that an actual steer angle is maintained equal to the weighted average.

Ken Ito

Papers

Automotive suspension control system with road-condition-dependent damping characteristics

Vehicle motion estimating system

Steering control system for wheeled vehicle

Model solving type vehicle steering control system with parameter identification

Vehicle steering control system using desired vehicle model