自适应制动系统原理与功能浅析

本文针对梅赛德斯-奔驰轿车的自适应制动系统,介绍了汽车制动电子控制的发展历程、自适应制动系统的组成、工作原理与功能。

ABR自适应制动系统功能简介

针对梅赛德斯-奔驰轿车的自适应制动系统,介绍了汽车制动电子控制的发展历程及自适应制动系统的功能。

Adaptive terminal sliding mode control for high-order nonlinear dynamic systems

An adaptive terminal sliding mode control (SMC) technique is proposed to deal with the tracking problem for a class of high-order nonlinear dynamic systems. It is shown that a function augmented sliding hyperplane can be used to develop a new terminal sliding mode for high-order nonlinear systems. A terminal SMC controller based on Lyapunov theory is designed to force the state variables of the closed-loop system to reach and remain on the terminal sliding mode, so that the output tracking error then converges to zero in finite time which can be set arbitrarily. An adaptive mechanism is introduced to estimate the unknown parameters of the upper bounds of system uncertainties. The estimates are then used as controller parameters so that the effects of uncertain dynamics can be eliminated. It is also shown that the stability of the closed-loop system can be guaranteed with the proposed control strategy. The simulation of a numerical example is provided to show the effectiveness of the new method.

Fuzzy control on automatic frequency tracking of ultrasonic vibration system with high power and high quality factor Q

In order to realize automatic tracking drift of resonance frequency of ultrasonic vibration system with high power and high quality factor Q, adaptive fuzzy control was studied with a self-fabricated ultrasonic plastic welding machine. At first, relations between amplitude of vibration and frequency as well as main loop current and amplitude of vibration were analyzed. From this analysis, we deduced that frequency tracking process of the vibration system can be concluded as an optimizing problem of one dimensional fluctuant extremum of main loop current in vibration system. Then a method of self-optimizing fuzzy control, used for the realization of automatic frequency tracking in vibration system, is presented on the basis of serf-optimizing adaptive control approach and fuzzy control approach. The result of experiments shows that the fuzzy self-optimizing method can solve the problem of tracking frequency drift very well. Response time of tracking in the system is less than 50 ms, which basically meets the requirements of frequency tracking in ultrasonic plastic welding machine.

Design of the multirobot intelligent team formation's control architecture and performance analysis of the system

The layered control architecture is designed for the need of the multirobot intelligent team formation.There are three levels:the cooperation task level,the coordination behavior level and the action planning level.The cooperation task level uses the potential grid method,which improves the safety of the path and reduces the calculation complexity.The coordination behavior level uses the reinforcement learning which can strengthen the robots’ intelligence.The action planning level uses the fuzzy planning methods to realize the action matching.The communication model transfers the message in different level.This architecture shows not only the independence and the intelligence of the single robot but also the cooperation and the coordination among the robots.In each level,the task is distributed reasonably and clearly.Finally the feasibility of the architecture is verified further in the simulation of the experiment.The expansibility of the architecture is good and the architecture can be used in the similar system.

Global Robust and Adaptive Output Feedback Dynamic Positioning of Surface Ships

A constructive method was presented to design a global robust and adaptive output feedback controller for dynamic positioning of surface ships under environmental disturbances induced by waves, wind, and ocean currents. The ship's parameters were not required to be known. An adaptive observer was first designed to estimate the ship's velocities and parameters. The ship position measurements were also passed through the adaptive observer to reduce high frequency measurement noise from entering the control system. Using these estimate signals, the control was then designed based on Lyapunov's direct method to force the ship's position and orientation to globally asymptotically converge to desired values. Simulation results illustrate the effectiveness of the proposed control system. In conclusion, the paper presented a new method to design an effective control system for dynamic positioning of surface ships.

Study on rate ripple and its adaptive suppression method in inertia guidance test equipment

This paper discusses causes of the rate ripple in inertia guidance test equipment IGET, systematically analyses their effects an the rate ripple in IGTE. The analysis result shows： The rate ripple caused by the periodic errors of inductosyn and angular encoder is higher at high speed than that caused by magnetic ripple torque and friction torque, and it cannot be eliminated by adjusting control parameters of the system. And based on the nonlinear adaptive control system theory, the paper puts forward a new control system scheme to eliminate the rate ripple caused by the periodic errors of inductosyn and angular encoder, develops the adaptive control rules and makes simulation and test. Experimental result shows a significant improvement on those tables for the period disturbs under the system scheme designed. By this plan, with the input of rate 200°/s, the rate ripple falls from 5°/s to 0. 4°/s within about 6s adaptive adjustment time, being a twelfth of before adaptation, which can not be reached by common classical controls. The experimental results conform with the simulation, which proves the validity and practicability of the plan.

Adaptive Control of Active Balancing System for a Fast Speed-varying Jeffcott Rotor with Actuator Time Delay

Due to actuator time delay existing in an adaptive control of the active balancing system for a fast speed-varying Jeffcott rotor, if an unsynchronized control force (correction imbalance) is applied to the system, it may lead to degradation in control efficiency and instability of the control system. In order to avoid these shortcomings, a simple adaptive controller was designed for a strictly positive real rotor system with actuator time delay, then a Lyapunov-Krasovskii functional was constructed after an appropriate transform of this sys-tem model, the stability conditions of this adaptive control system with actuator time delay were derived. After adding a filter function, the active balancing system for the fast speed-varying Jeffcott rotor with actuator time delay can easily be converted to a strictly positive real system, and thus it can use the above adaptive controller satisfying the stability conditions. Finally, numerical simulations show that the adaptive controller proposed works very well to perform the active balancing for the fast speed-varying Jeffcott rotor with actuator time delay.

Robust adaptive cross-coupling position control of biaxial motion system

The stability and synchronous performance are usually hard to be improved simultaneously in the biaxial cross-coupling position motion control system.Based on analyzing the characteristics of the cross-coupling control system,a robust adaptive cross-coupling control strategy is proposed.To restrict influences of destabilizing factors and improve both of stability and synchronous performance,the strategy forces dual axes to track the same reference model using Narendra adaptive control theory.And then,a robust parameters adaptive law is proposed.The stability analysis of the proposed strategy is conducted by applying Lyapunov stability theory.Related simulations and experiments indicate that the proposed strategy can improve synchronous performance and stability simultaneously.

ADAPTIVE SYSTEMS THEORY: SOME BASIC CONCEPTS, METHODS AND RESULTS

The adaptive systems theory to be presented in this paper consists of two closely related parts: adaptive estimation (or filtering, prediction) and adaptive control of dynamical systems. Both adaptive estimation and control are nonlinear mappings of the on-line observed signals of dynamical systems, where the main features are the uncertain-ties in both the system's structure and external disturbances, and the non-stationarity and dependency of the system signals. Thus, a key difficulty in establishing a mathematical theory of adaptive systems lies in how to deal with complicated nonlinear stochastic dynamical systems which describe the adaptation processes. In this paper, we will illustrate some of the basic concepts, methods and results through some simple examples. The following fundamental questions will be discussed: How much information is needed for estimation? How to deal with uncertainty by adaptation? How to analyze an adaptive system? What are the convergence or tracking performances of adaptation? How to find the proper rate of adaptation in some sense? We will also explore the following more fundamental questions: How much uncertainty can be dealt with by adaptation ? What are the limitations of adaptation ? How does the performance of adaptation depend on the prior information ? We will partially answer these questions by finding some 'critical values' and establishing some 'Impossibility Theorems' for the capability of adaptation, for several basic classes of nonlinear dynamical control systems with either parametric or nonparametric uncertainties.