Using improved particle swarm optimization to tune PID controllers in cooperative collision avoidance systems

The introduction of proportional-integral-derivative (PID) controllers into cooperative collision avoidance systems (CCASs) has been hindered by difficulties in their optimization and by a lack of study of their effects on vehicle driving stability, comfort, and fuel economy. In this paper, we propose a method to optimize PID controllers using an improved particle swarm optimization (PSO) algorithm, and to better manipulate cooperative collision avoidance with other vehicles. First, we use PRESCAN and MATLAB/Simulink to conduct a united simulation, which constructs a CCAS composed of a PID controller, maneuver strategy judging modules, and a path planning module. Then we apply the improved PSO algorithm to optimize the PID controller based on the dynamic vehicle data obtained. Finally, we perform a simulation test of performance before and after the optimization of the PID controller, in which vehicles equipped with a CCAS undertake deceleration driving and steering under the two states of low speed (≤50 km/h) and high speed (≥100 km/h) cruising. The results show that the PID controller optimized using the proposed method can achieve not only the basic functions of a CCAS, but also improvements in vehicle dynamic stability, riding comfort, and fuel economy.     

考虑车辆横向主动安全的智能驾驶员模型

结合智能车面临的横向安全问题, 设计了一种具有横向安全性的智能驾驶员模型. 该系统由转向控制、速度控制和决策规划三个模块组成. 该系统的主要作用包括: 一是通过在转向控制中加入主要约束提高车辆在转向过程中的横向稳定性, 减小车辆发生侧滑、侧倾、侧偏等风险; 二是在换道场景下, 决策规划单元合理分析交通环境中的车间距并计算出驶入临近车道的速度和轨迹, 使智能车实现安全换道. CarSim/Simulink仿真结果表明, 该智能驾驶员系统提高了车辆行驶的横向安全性.     

虚拟轨道列车全轮主动转向控制研究

针对多铰接式虚拟轨道列车的转向问题,基于后车跟随首车行驶轨迹运行的思路,提出了一种全轮主动转向控制方法.首先,利用移位寄存器储存首车的行驶轨迹作为目标路径;其次,根据车体后轴实际路径和目标路径间的横向偏差量,基于PID控制器和Stanley算法确定车体后轮转角,进一步利用阿克曼转向几何原理计算后车前轮的转角;最后,搭建TruckSim与Matlab/Simulink联合仿真平台,结合典型工况进行仿真分析.仿真结果表明,本文设计的控制方法有效提高了拖车模块对牵引车模块的跟随性能,减小了车间铰接处的作用力、车体的质心侧偏角和轮胎侧向力,从而提高了列车在转弯时的稳定性.     

Educational training software for modelling and synthesis of controllers for robotic manipulators and robotized manufacturing cells

A general software system aimed at computer-aided design of controllers for robots and robotized technological systems is described in this paper. The software system includes modules for the synthesis of various levels of robot controller as well as controllers of complex robotized technological systems. The software includes simulation of robotic systems within manufacturing cells using various types of models: complete dynamic models, kinematic models and simple models in the form of finite automata. Using these modelsvarious algorithms for all controls levels in robot controllers may be synthesized taking into account the actual interaction between the robot and its environment. The software system enables the solution of the important problem of the interaction between higher and lower levels of controllers. Finally, a general purpose controller as a target system for the proposed software is described. The controller is designed as an open system allowing the user to apply various control laws and to run in conjunction with an actual robot. The general software system together with the controller represents a powerful educational tool in modern robotics.     

Fuzzy Logic Based Approach to Design of Flight Control and Navigation Tasks for Autonomous Unmanned Aerial Vehicles

This paper proposes a fuzzy logic based autonomous navigation controller for UAVs (unmanned aerial vehicles). Three fuzzy logic modules are developed under the main navigation system for the control of the altitude, the speed, and the heading, through which the global position (latitude–longitude) of the air vehicle is controlled. A SID (Standard Instrument Departure) and TACAN (Tactical Air Navigation) approach is used and the performance of the fuzzy based controllers is evaluated with time based diagrams under MATLAB’s standard configuration and the Aerosim Aeronautical Simulation Block Set which provides a complete set of tools for rapid development of detailed six-degree-of-freedom nonlinear generic manned/unmanned aerial vehicle models. The Aerosonde UAV model is used in the simulations in order to demonstrate the performance and the potential of the controllers. Additionally, FlightGear Flight Simulator and GMS aircraft instruments are deployed in order to get visual outputs that aid the designer in the evaluation of the controllers. Despite the simple design procedure, the simulated test flights indicate the capability of the approach in achieving the desired performance.     

Fuzzy logic techniques for navigation of several mobile robots

In this paper, navigation techniques for several mobile robots as many as one thousand robots using fuzzy logic are investigated in a totally unknown environment. Fuzzy logic controllers (FLC) using different membership functions are developed and used to navigate mobile robots. First a fuzzy controller has been used with four types of input members, two types of output members and three parameters each. Next two types of fuzzy controllers have been developed having same input members and output members with five parameters each. Each robot has an array of ultrasonic sensors for measuring the distances of obstacles around it and an infrared sensor for detecting the bearing of the target. These techniques have been demonstrated in various exercises, which depicts that the robots are able to avoid obstacles as well as negotiate the dead ends and reach the targets efficiently. Amongst the techniques developed, FLC having Gaussian membership function is found to be most efficient for mobile robots navigation.     

Evolution of a Negative-Rule Fuzzy Obstacle Avoidance Controller for an Autonomous Vehicle

A fuzzy obstacle avoidance controller is designed for an autonomous vehicle. The controller is given the capability for obstacle avoidance by using negative fuzzy rules in conjunction with traditional positive ones. Negative fuzzy rules prescribe actions to be avoided rather than performed. A rule base of positive rules is specified by an expert for directing the vehicle to the target in the absence of obstacles, while a rule base of negative rules is experimentally determined from expert operation of the vehicle in the presence of obstacles. The consequents of the negative-rule system are codified into a chromosome, and this chromosome is evolved using an evolutionary algorithm. The resulting fuzzy system has far fewer rules than would be necessary for an obstacle avoidance controller using purely positive rules, while in addition retaining greater interpretability.     

Adaptive steering control without using measurements of lateral velocity of vehicles

In this paper, we propose an adaptive steering controller without using measurements of lateral velocity of vehicles. At first, we show a new dynamic expression suitable for the design of a stable adaptive steering controller without using the lateral velocity. Next, we develop an ideal vehicle model. In the designed ideal vehicle model, a good steering performance can be achieved even if the drivers’ steering characteristics vary. Finally, an adaptive steering controller is developed, so that the actual vehicles can track ideal vehicle model and realize good steering performance.     

Collision avoidance by fuzzy logic control for automated guided vehicle navigation

A fuzzy approach to collision avoidance for automated guided vehicle (AGV) navigation is proposed. Static obstacles with no a priori position information as well as moving obstacles with unknown trajectories are considered in this study. Intuitive and subjective human ideas of collision avoidance are modeled into fuzzy rules. Fuzzy logic is applied in the inference procedure for AGV navigation, such that the AGV is guided from the starting point toward the target without colliding with obstacles. Furthermore, the proposed method can also be used for the navigation of multiple AGVs, where each AGV must avoid other AGVs as well as obstacles in the environment. Simulation results are presented to show the feasibility of the proposed fuzzy approach. © 1994 John Wiley & Sons, Inc.     

Mobile robot tracking of pre-planned paths

A method of mobile robot steering control around pre-planned paths is presented. The system can maneuver accurately at low speeds by deriving control parameters as functions of vehicle velocity. The peak demand on the steering controller is reduced, by distributing steering curvature changes evenly over the extent of a maneuver.     

Selected methods of control of the scanning and tracking gyroscope system mounted on a combat vehicle

At present, remotely controlled modules of weaponry are becoming the basic equipment of modern army. The device for searching and observing air targets is one of the most significant elements of a weapon module. The device of that type in the form of the scanning and tracking gyroscope system is considered in the article. The process of automatic search of a target is carried out during the movement of a combat vehicle as well as during its manoeuvres. After a target is detected, it is tracked till it has been destroyed by the fired missile. The algorithm of control of the scanning and tracking gyroscope system, mounted on the deck of a combat vehicle, was developed. The optimized, classic PD controller, fuzzy controller PD type, fuzzy controller PID type and adaptive fuzzy controller were designed. Numerical research of the dynamics of the controlled gyroscope system and the assessment of the quality of control were conducted. The results of research are presented in a graphical form.     

Fuzzy Logic Based Approach to Design of Autonomous Landing System for Unmanned Aerial Vehicles

This paper is concerned with autonomous flight of UAVs and proposes a fuzzy logic based autonomous flight and landing system controller. Besides three fuzzy logic controllers which are developed for autonomous navigation for UAVs in a previous work as fuzzy logic based autonomous mission control blocks, three more fuzzy logic modules are developed under the main landing system for the control of the horizontal and the vertical positions of the aircraft against the runway under a TACAN (Tactical Air Navigation) approach. The performance of the fuzzy logic based controllers is evaluated using the standard configuration of MATLAB and the Aerosim Aeronautical Simulation Block Set which provides a complete set of tools for rapid development of 6 degree-of-freedom nonlinear generic manned/unmanned aerial vehicle models. Additionally, FlightGear Flight Simulator and GMS aircraft instruments are deployed in order to get visual outputs that aid the designer in evaluating the performance and the potential of the controllers. The simulated test flights on an Aerosonde indicate the capability of the approach in achieving the desired performance despite the simple design procedure.     

A geometric approach to target convergence and obstacle avoidance of a nonstandard tractor‐trailer robot

In this article, a solution to target convergence and obstacle avoidance problem of an underactuated nonstandard n‐trailer robot is proposed. With a new geometric approach, we propose autonomous velocity and steering angle controllers for the car‐like tractor robot such that the tractor‐trailer system moves from an initial position to a designated target. The proposed method simultaneously takes into account the dynamics constraints of the system and also ensures that the robot avoids any fixed obstacles on its way to the target. We also generalize the results to control the motion of the nonstandard n‐trailer system with an arbitrary number of passive trailers, a mathematically challenging nonlinear underactuated system, given that the angular velocity of a trailer is dependent on the angular velocity of the preceding trailer. The effectiveness of the new geometric approach and the stabilizing control inputs is verified using computer simulations.     

Coordinated circumnavigation by multiple agents under directed topology

ABSTRACT

This paper focuses on the coordinated circumnavigation problem for multiple agents with directed communication topology. All agents are required to be evenly spaced around a moving target, and orbit around it with prescribed radii and circular velocity. We divide the coordinated circumnavigation system into a cascaded system consisting of a standoff tracking subsystem and a spacing distribution subsystem. A tracking controller and an additional controller for the two subsystems are developed, respectively. The global uniform stability of the coordinated circumnavigation system is analysed using the cascaded control theory. The presented controllers render each individual agent circumnavigating the target with the desired requirements. More importantly, we show that the derived tracking controller is a general extension of existing controllers for single agent circumnavigation problem. Another feature of the proposed controllers is that the directed topology considered only needs to have a directed spanning tree. Furthermore, the proposed controllers take the velocity constraints into consideration, that is more rational for practical applications. Numerical simulations are provided to verify the effectiveness of the proposed methods.     

基于FPGA的千兆以太网终端显示系统的设计

VGA（视频图像阵列）作为一种标准的显示接口得到广泛应用;千兆以太网具有传输速度快、传输距离远、稳定可靠等优点,是当前嵌入式系统的应用热点;FPGA拥有丰富的逻辑和光脚资源,常用于高速数据处理和通信的嵌入式系统。文中结合以上三点,介绍了基于FPGA的千兆以太网终端显示系统的设计。通过对该系统方案进行分析,将设计分为3个模块：数据包接收及解析模块、双口RAM缓存模块和VGA控制器模块。文中详细介绍了这3个模块的设计方法,并在此技术上实现了3个模块协同工作完成整个系统的功能,并给出了系统仿真结果和显示效果。     

Autonomous intelligent vehicle and its performance in automated traffic systems

In this paper, we develop a completely self-contained controller (SCC) for implementing all functions of autonomous intelligent cruise control (AICC). SCC consists of two modules: the decision module analyses the current scenario and infers control mode that associates with a certain manoeuvre; the control module implements the command provided by the decision. A rule-based logic is used in the decision to infer an appropriate manoeuvre. To execute the manoeuvre, a control scheme in the control module is designed to implement this task. It is proven that the proposed SCC can avoid slink-effect occurring when a vehicle string is moving on a highway. Examples are given to show that SCC can handle all possible traffic scenarios with satisfactory performance. The potential flow increases when all vehicles on a highway equipped with the proposed controller are examined by running a highway simulator in which the traffic is under very realistic assumptions.     

基于SPEAr320和STM32的GLC设计

图形化逻辑控制器（GLC）是人机界面（HMI）和可编程逻辑控制器（PLC）相结合的产品.详细阐述了基于SPEAr320和STM32的GLC设计方案,解析其主模块和IO模块的硬件及软件框架,着重分析了两个模块之间的通信机制,展示了一个真正的产品级设计方案.     

A Novel LQG Controller of Active Suspension System for Vehicle Roll Safety

To improve vehicle roll safety during steering operation at high running speed, a new design approach for Linear Quadratic Gaussian (LQG) controller of active suspension system is proposed. Key steps of the new approach are as follows: 1) The front axle steered angle is written into a differential equation in accord with the minimum phase system and combines with the original system into the augmented system equation; 2) positive infinitesimals respectively including controls are added to the index; Thirdly, weights of the evaluating indicators of the LQG controller are determined by using analytic hierarchy process (AHP) and normalization methods based on vehicle motion statistics under the double-lane change maneuver as the typical steering maneuver. Performance comparisons are implemented between the active suspension system and the passive one under the double-lane change, slalom and fish-hook maneuvers. Results verify that the active suspension system with the proposed controller can achieve better vehicle roll safety and has a good adaptability under different steering maneuvers.     

Four wheel steering control by fuzzy approach

This study introduces a fuzzy four-wheel steering control design method for automotive vehicles. After the analysis of some stability aspects of the vehicle lateral motion, including front steering angle variations, the representation of vehicle nonlinear model by Takagi-Sugeno (T-S) fuzzy model is presented. Next, based on the fuzzy model, a fuzzy controller is developed to improve the stability of the vehicle. Sufficient conditions for stability and stabilization of the T-S fuzzy model using fuzzy feedback controllers is given. To demonstrate the effectiveness of the proposed fuzzy controller, simulation results are given showing the performance improvements of the vehicle in terms of the stability and the maneuverability in critical situations.     

高速公路实时交通流模糊逻辑优化控制系统设计

高速公路交通流特征复杂多变,受到诸多影响因素的共同作用,如天气、道路状况、车辆类型等等。因此,如何获取交通流逻辑控制条件并实现精准调节难度较大。为此,本研究设计新的高速公路实时交通流模糊逻辑优化控制系统。对于系统的硬件部分,设计车流控制模块、无线传输车载终端、实时交通流逻辑调度模块、模糊控制器模块,并确定各个模块之间实时连接关系。对于系统的软件部分,求解交通流逻辑控制条件,联合高速公路实时通行相位条件,调节模糊控制器,并根据高速公路交通路网模型,推导交通流优化控制条件的求解表达式,完成高速公路实时交通流模糊逻辑优化控制系统的设计。实验结果表明,本系统可以解决逻辑协调错误的问题,且能够有效控制高速公路车流量。