外文翻譯----非線性pid控制在一系列卡車abs問題中的應(yīng)用-展示頁
2025-05-27 11:18本頁面
【正文】 ower in response and harder to control than a hydraulic brake system. The control action of the brake system is discrete. The brake pressure is controlled by discrete valves (open or close). The brake pressure can be controlled to increase, hold constant or decrease. Through PWM (Pulse Width Modulation), the actions of the discrete valves are mapped into a continues analog control signal ranging from –1 to +1, where –1 means fully exhausting pressure, +1 means fully building up pressure and 0 means holding pressure as constant. 2. The measurement of the brake pressure is not available, which makes the control of the pneumatic brake system even more difficult. The ABS controller must deal with the brake dynamics and the wheel dynamics as a whole plant. 3. The measurement of the vehicle velocity or vehicle acceleration is not available. The only feedback signals are two or four channels of wheel angular velocity. It poses a challenging problem for the vehicle velocity estimation since the vehicle velocity is necessary to set the wheel reference velocity. A separate study was carried out to resolve this issue in [2]. 4. The plex dynamics of the tractor/trailer system and the large variations of the truck operation condition set a very stringent requirement for the ABS controller. The tuning and testing of a truck ABS are also much more difficult than an ABS for passenger cars. Current Technology Various control strategies have been implemented in real ABS products or discussed in publications. Since the technologies used in mercial ABS products are usually kept as trade secrets, it is very difficult to determine their detailed control algorithms. From the literature available [3, 4, 5, 6], a few algorithms use an approach similar to bangbang control. They usually have two or more threshold values for the wheel deceleration or the wheel slip. Once the calculated wheel deceleration or wheel slip is over one of the threshold values, the brake pressure is manded to increase, hold constant or decrease. This algorithm will result in a peakseeking strategy in the μ?slip curve or forcing the wheel deceleration/slip to be within a particular range. Finite state machine methods are also widely applied in the industry. Based upon the measured signals such s wheel velocity, vehicle
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