发布时间 : 星期日 文章汽车转向控制中英文对照外文翻译文献更新完毕开始阅读fe70602566ec102de2bd960590c69ec3d5bbdb6d
system,\officer.
\monitors what the vehicle controls indicate should be happening, compares that to what is actually happening, then works to compensate for the difference,\said Johannes Graber, ASMS program manager at ITT Automotive Europe. ITT's system should begin appearing on vehicles worldwide near the end of the decade, according to Tom Mathues, director of engineering of Brake & Chassis Systems at ITT Automotive North America. Company engineers are now adapting the system to specific car models from six original equipment manufacturers.
A less-sophisticated and less-effective Bosch stability control system already appears on the 1995 750iL and 850Ci V-12 models from Munich-based BMW AG. The BMW Dynamic Stability Control (DSC) system uses the same wheel-speed sensors as traction control and standard anti-lock brake (ABS) systems to recognize conditions that can destabilize a vehicle in curves and corners. To detect such potentially dangerous cornering situations, DSC measures differences in rotational speed between the two front wheels. The DSC system also adds a sensor for steering angle, Utilizes an existing one for vehicle velocity, and introduces its own software control elements in the over allantilock-brake/traction-control/stability-control system.
The new Bosch and ITT Automotive stability control systems benefit from advanced technology developed for the aerospace industry. Just as in a supersonic fighter, the automotive stability control units use a sensor-based computer system to mediate between the human controller and the environment - in this case, the interface between tire and road. In addition, the system is built around a gyroscopelike sensor design used for missile guidance.
BEYOND ABS AND TRACTION CONTROL
Stability control is the logical extension of ABS and traction control, according to a Society of Automotive Engineers paper written by van Zanten and Bosch colleagues Rainer Erhardt and Georg Pfaff. Whereas ABS intervenes when wheel
lock is imminent during braking, and traction control prevents wheel slippage when accelerating, stability control operates independently of the driver's actions even when the car is free-rolling. Depending on the particular driving situation, the system may activate an individual wheel brake or any combination of the four and adjust engine torque, stabilizing the car and severely reducing the danger of an uncontrolled skid. The new systems control the motion not only during full braking but also during partial braking, coasting, acceleration, and engine drag on the driven wheels, circumstances well beyond what ABS and traction control can handle.
The idea behind the three active safety systems is the same: One wheel locking or slipping significantly decreases directional stability or makes steering a vehicle more difficult. If a car must brake on a low-friction surface, locking its wheels should be avoided to maintain stability and steerability.
Whereas ABS and traction control prevent undesired longitudinal slip, stability control reduces loss of lateral stability. If the lateral forces of a moving vehicle are no longer adequate at one or more wheels, the vehicle may lose stability, particularly in curves. What the drive?逾",半",??????? \spinning around the vehicle's axis. A separate sensor must recognize this spinning, because unlike ABS and traction control, a car's lateral movement cannot be calculated from its wheel speeds.
SPIN HANDLERS
The new systems measure any tendency toward understeer (when a car responds slowly to steering changes), or over-steer (when the rear wheels try to swing around). If a car understeers and swerves off course when driven in a curve, the stability control system will correct the error by braking the inner (with respect to the curve) rear wheel. This enables the driver, as in the case of ABS, to approach the locking limit of the road-tire interface without losing control of the vehicle. The stability control system may reduce the vehicle's drive momentum by throttling back the engine and/or by braking on individual wheels. Conversely, if the hteral stabilizing force on the rear axle is insufficient, the danger of oversteering may result in rear-end