Steering angle

We recall that, for flat array, the steered angle beam, 9, depends only on ultrasound celerity in the propagation medium, ci, the time delay between each element, 5t, and the pitch element, p, through the relation ... 

The vision of braking and steering by wire will demand new, extremely reliable sensors. Even in early implementations of steer-by-wire systems, in which manual control can override any system failure, more than one sensor is normally used for the sake of redundancy. Many of the sensor principles required are already established in the market, including steering-angle sensors (e.g., for vehicle dynamics control) and pedal-position sensors. Mechanical action or feedback control, however, will drive the emergence of torque and force sensors. 

One high-volume application is the wheel speed detection for anti-lock braking (ABS) systems. Wheel speed information is also needed in modern vehicle dynamics control (VDC) and navigation systems. Both require, in addition to the wheel speed, the steering angle as an input value, which is also often provided by magnetic sensors. A classic field of application is the power train, in which magnetic sensors deliver information about the cam and crank shaft positions as well as the transmission speed. 

Electronic control systems such as ESP, EPS, ABC, ECD, ACC, and navigation systems need steering-angle data as part of the information available on the vehicle network (CAN = control area network). Some ESP system suppliers and car manufacturers require an SAS to fulfill safety requirements. Fig. 7.11.2 shows a modular approach around an SAS core technology. 

Fig. 7.11.2 Building a steering-angle measuring system (source Valeo)...

Function Modeling of Steering-Angle Sensor Principles... 

Fig. 7.11.3 Contactless steering-angle sensors with active and fixed transmitter...

Fig. 7.11.8 Steering-angle sensor using Gray code technique [15]...

Fig. 7.11.9 Steering-angle sensor principle based on an optical array [9]...

Fig. 7.11.19 True power on and absolute steering-angle sensor measuring principle (source Bosch)...

Main Application Fields for Steering-Angle Sensors... 

Steering-Angle Sensor an Important Part of the Electronic Stability Program... 

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