铰接式履带车辆转向特性仿真研究

针对深海富钴结壳行走装置必须适应复杂恶劣地形和较强的越障性能,提出一种具有四个液压缸的主动式联结装置的铰接式履带车辆,通过对铰接式履带车辆进行转向运动学分析,以及对联接装置的转向工作机理进行分析,得出了转向液压缸活塞杆伸长量与车辆理论转向半径的关系,并采用多体动力学仿真软件ADAMS的履带车辆工具箱ATV 建立了铰接式履带车辆的虚拟样机模型,仿真得到了铰接转向角速度,铰接转向半径,铰接转向所耗功率与差速转向所耗功率的关系,仿真结果表明,仿真模型具有较高的精度,能够对转向过程中主要参数随时间的变化历程进行仿真,可以为铰接式履带车辆转向过程的研究提供理论分析根据.     

履带动态张紧力的动力学仿真

履带车辆的履带动态张紧力在很大程度上决定行动部分各元件的载荷、履带寿命、功率损失和履带脱落的概率.该文用多体动力学软件RecurDyn,以某履带车辆为原形建立履带车辆的多刚体模型,并建立有效的不同等级的路面模型.模型中履带子系统有六个自由度,能够真实的模拟履带运动的实际情况.通过对车体上几个固定位置处履带张紧力的变化和履带上参考履带板的受力变化,来检测履带动态张紧力的变化.分别改变路面、速度、预张紧力等相关影响因素做多组计算,对比分析了履带动态张紧力的变化情况.     

Adaptive Robust Three‐dimensional Trajectory Tracking for Actively Articulated Tracked Vehicles*

A new approach is proposed for an adaptive robust three‐dimensional (3D) trajectory‐tracking controller design. The controller is modeled for actively articulated tracked vehicles (AATVs). These vehicles have active sub‐tracks, called flippers, linked to the ends of the main tracks, to extend the locomotion capabilities in hazardous environments, such as rescue scenarios. The proposed controller adapts the flippers configuration and simultaneously generates the track velocities, to allow the vehicle to autonomously follow a given feasible 3D path. The approach develops both a direct and differential kinematic model of the AATV for traversal task execution correlating the robot body motion to the flippers motion. The benefit of this approach is to allow the controller to flexibly manage all the degrees of freedom of the AATV as well as the steering. The differential kinematic model integrates a differential drive robot model, compensating the slippage between the vehicle tracks and the traversed terrain. The underlying feedback control law dynamically accounts for the kinematic singularities of the mechanical vehicle structure. The designed controller integrates a strategy selector too, which has the role of locally modifying the rail path of the flipper end points. This serves to reduce both the effort of the flipper servo motors and the traction force on the robot body, recognizing when the robot is moving on a horizontal plane surface. Several experiments have been performed, in both virtual and real scenarios, to validate the designed trajectory‐tracking controller, while the AATV negotiates rubble, stairs, and complex terrain surfaces. Results are compared with both the performance of an alternative control strategy and the ability of skilled human operators, manually controlling the actively articulated components of the robot.     

新型铰接转向机构参数优化设计

该文介绍了一种新型的铰接转向机构,采用特殊的双摇杆转向型式,以采用此转向机构的某重载车辆为研究对象,利用CAE软件ADAMS,建立了机构铰点参数化的虚拟样机,采用Design study方法,得出转向机构参数性能的变化情况以及设计参数的近似敏感度,得到关联度最大铰点。采用OPTDES-SQP优化模型,设置目标函数,建立了以综合转向性能最优为优化目标的优化设计模型。经过优化,转向力臂差变化比率 为﹣74.6%,转向角度增加+2.22%,通过实际应用,减小了转向过程转向液压系统的振动和冲击,增加了系统转向稳定性,取得了良好的效果,为该转向系统的控制与操作提供了必要的依据。     

铰接履带式海底采矿车越障性能仿真研究

针对产于复杂恶劣地形海山表面的深海矿产资源钻结壳,提出了钴结壳采矿车采用铰接式履带车的技术方案,利用机械系统动力学仿真软件ADAMS/ATV履带车工具包,开发了铰接履带式海底采矿车的三维动力学模型和虚拟样机,进行了其通过垂赶障碍和沟槽地形的越障性能仿真研究和结果分析.仿真研究表明,铰接履带式海底采矿车建模正确,仿真真实,越障性能优良,且超过我国钴结壳采矿车技术要求,仿真数据可为物理样机研制提供技术参考.     

履带模型与仿真

仿真技术应用于履带车辆的研究，降低了研究成本，缩短了研制周期，有力地推动了履带车辆的发展。履带模型在履带车辆建模与仿真中是棘手问题。本文对履带车辆仿真中常见的两类履带模型-柔性履带模型和刚性履带模型的模型机理进行了分析，并分别将两类履带模型应用到履带车辆的平稳性模型中，通过仿真比较了两类履带模型的差异。     

Motion Control of a 6WD/6WS wheeled platform with in-wheel motors to improve its maneuverability

Multi-axle driving mobile platform that are favored in special environments require high driving performance, steering performance, and stability. Among these, six wheel drive and six wheel steering vehicles hereinafter called 6WD/6WS, gain structural safety by distributing the load and reducing the pitching motion during rapid acceleration and braking. 6WD/6WS mobile platforms are favorable for military use, particularly in off-road operations because of their high maneuverability and mobility on extreme terrains and obstacles. 6WD vehicles that use in-wheel motors can generate independent wheel torque without a need for additional hardware. Conventional vehicles, however, cannot generate an opposite driving force on wheels on both sides. In an independent steering and driving system six-wheel vehicles show better performance than conventional vehicles. This paper discusses the improvement of the cornering performance and maneuverability of 6WD/6WS mobile platform using independent wheel torque and independent steering on each wheel. 6WD/6WS vehicles fundamentally have satisfactory maneuverability under low speed, and sufficient stability at high speed. Consequently, there should be a control strategy for improving their cornering performance using the optimum tire forces that satisfy the driver’s command and minimize energy consumption. From the driver’s commands (i.e., the steering angle and accelerator/brake pedal stroke), the desired yaw moment with virtual steering, desired lateral force, and desired longitudinal force are obtained. These three values are distributed to each wheel as torque and steering angle, based on the optimum tire force distribution method. The optimum tire force distribution method finds the longitudinal/lateral tire forces of each wheel that minimize cost function, which is the sum of the normalized tire forces. This paper describes a 6WS/6WD vehicle with improved cornering performance and the results are validated through TruckSim simulations.

     

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.     

基于RecurDyn的滑转对履带车辆加速性能影响研究

采用多体动力学仿真软件RecurDyn的履带车辆子系统Track(HM),建立履带车辆多体动力学模型,并在MATLAB/Simulink下建立了整车动态系统仿真模型。对履带车辆在硬、软两种地面的加速过程进行动力学仿真和对比分析,着重讨论在不同滑转的条件下履带车辆的加速性能以及滑转率对加速性能的影响,为履带车辆加速性能的研究与滑转的控制提供指导。     

The Indirect Shared Steering Control Under Double Loop Structure of Driver and Automation

Due to the critical defects of techniques in fully autonomous vehicles, man-machine cooperative driving is still of great significance in today’s transportation system. Unlike the previous shared control structure, this paper introduces a double loop structure which is applied to indirect shared steering control between driver and automation. In contrast to the tandem indirect shared control, the parallel indirect shared control put the authority allocation system of steering angle into the framework to allocate the corresponding weighting coefficients reasonably and output the final desired steering angle according to the current deviation of vehicle and the accuracy of steering angles. Besides, the active disturbance rejection controller (ADRC) is also added in the frame in order to track the desired steering angle fleetly and accurately as well as restrain the internal and external disturbances effectively which including the steering friction torque, wind speed and ground interference etc. Eventually, we validated the advantages of double loop framework through three sets of double lane change and slalom experiments, respectively. Exactly as we expected, the simulation results show that the double loop structure can effectively reduce the lateral displacement error caused by the driver or the controller, significantly improve the tracking precision and keep great performance in trajectory tracking characteristics when driving errors occur in one of driver and controller.      

JSAE-SICE benchmark problem for vehicle dynamics control

Recently many new types of small vehicles for future urban societies have been proposed and developed. Such small vehicles tends to have reduced stability and handling ability than conventional vehicles because of their lighter weight and reduced tire performance. To cope with this problem by active collaboration of Japanese academia and industries, a benchmark problem of designing vehicle control logic for an articulated In-Wheel-Motor vehicle was settled by Japanese society of automotive industries and academia. For this purpose, simulation models of the new vehicle using multi-physics acausal modeling language Modelica were provided from the industry side. Challengers were requested to design controllers of tire steering angle, tire camber angle and tire driving force to satisfy requested vehicle dynamic characteristics. There also were some restrictions about the range of actuators. Four test scenarios were given to evaluate the control performance. Many challengers from Japanese Universities have tackled with this benchmark problem. Some results of their researches are also introduced in this paper.     

Directional control–response compatibility of joystick steered shuttle cars

Shuttle cars are an unusual class of vehicle operated in underground coal mines, sometimes in close proximity to pedestrians and steering errors may have very serious consequences. A directional control–response incompatibility has previously been described in shuttle cars which are controlled using a steering wheel oriented perpendicular to the direction of travel. Some other shuttle car operators are seated perpendicular to the direction of travel and steer the car via a seat mounted joystick. A virtual simulation was utilised to determine whether the steering arrangement in these vehicles maintains directional control–response compatibility. Twenty-four participants were randomly assigned to either a condition corresponding to this design (consistent direction), or a condition in which the directional steering response was reversed while driving in-bye (visual field compatible). Significantly less accurate steering performance was exhibited by the consistent direction group during the in-bye trials only. Shuttle cars which provide the joystick steering mechanism described here require operators to accommodate alternating compatible and incompatible directional control–response relationships with each change of car direction.

Practitioner Summary: A virtual simulation of an underground coal shuttle car demonstrates that the design incorporates a directional control–response incompatibility when driving the vehicle in one direction. This design increases the probability of operator error, with potential adverse safety and productivity consequences.     

履带车辆高速转向动力学仿真

采用多体动力学仿真软件MSC Adams 的履带车辆工具箱ATV,建立某型履带车辆三维动力学模型,对履带车辆在硬、软两种地面的高速转向过程进行动力学仿真和对比分析,着重讨论履带车辆在软地面高速转向的动力学特性,为履带车辆转向性能的研究与高速转向的正确操作提供指导.     

Human Factors Assessment of Vehicle Power Steering

Abstract

The handling and steering of an in-service wheeled vehicle were investigated, following a number of adverse reports. This paper presents the subjective assessments of the vehicle's power steering, which were included in that investigation.

The effects of three different power steering settings were appraised by driving the vehicles on a road-test track and cross-country. In addition, two questionnaires enabled the drivers' overall views and comments on specific factors to be recorded. Analysis of variance showed that the subjectively assessed differences between the three vehicle power steering settings were statistically significant at the 2 per cent level. The six civilian and six military drivers' views were congruent and course differences (road or cross-country) did not consistently and significantly affect the overall assessment. The drivers' stated preferences among the vehicles supported the analysis of variance results.

Incidents observed during the trials showed that drivers could lose control of the vehicle because of excessive speed and/or faulty driving technique, independently of power steering characteristics. This suggests that many incidents could be prevented by giving specific instructional guidelines to drivers during training and by the incorporation of a speed limiting device in any modifications to the vehicle tested.     

基于MotionView整车虚拟试验场仿真的后转向节强度分析

由于车辆行驶状况复杂多样,传统静态工况无法复现各类恶劣路况下后底盘转向节真实应力,因此在利用MotionView建立整车刚柔耦合多体动力学模型的基础上,将后转向节利用柔性体进行模拟;在进行虚拟试验场仿真分析的同时采用模态综合法计算结构动应力,得到后转向节最高应力位置及发生时刻.仿真结果与整车道路试验结果的对比表明仿真方法准确.     

电传动履带车辆转向行驶性能仿真分析

该文首先采用一种优选电传动方案建立了新的电传动履带车辆模型。然后在对电传动履带车辆转向行驶基本理论分析的基础上，对电传动履带车辆的转向行驶性能进行了仿真分析。结果表明：履带车辆采用电传动在转向性能方面具有很大的优势，可以实现小半径甚至是原地中心转向，转向为无级的，且转向的灵活性和快速性很好。再生转向时产生的再生能量很大，可以通过控制充分利用再生能量。为在不同的地面情况下提高转向的灵活性和快速性，应尽量在转向前降低车速，使驱动电机在低速大扭矩下工作，由于低速时车辆实现的转向半径可以很小，转向角速度可以很大，从而实现快速、灵活转向。     

基于反步法的四轮车体跟踪控制半实物仿真研究

人机共驾是非自动驾驶迈向全自动驾驶的中间过渡技术,其半实物仿真能显著减少实车的实验消耗.针对不具备四轮车体模型的仿真平台以及传统坐标系转换方法的局限,基于两轮差速移动车体模型和四轮车体模型的位姿状态误差,利用一种非线性反步控制方法,实现对四轮车体模型运动轨迹的有效实时跟踪.通过方向盘和踏板在虚拟现实环境下进行人机共驾模拟,为开发更逼真的人机共驾及模拟辅助驾驶系统提供了参考.以车体前进方向速度和导向轮角度作为系统输入,通过考察两轮差速移动车体和四轮车体的位姿状态误差,分别在数值仿真和半实物仿真实验条件下,对比并验证了所提出方法的有效性,行驶方向上10km的平均累积误差为4.56m.     

四轮转向半挂汽车列车行驶稳定性仿真研究

通过分析四轮转向(4WS)半挂汽车列车行驶性能,为在牵引车上采用4WS技术能提高整个汽车列车行驶稳定性提供依据.建立4WS半挂汽车列车简化三自由度单轨动力学模型,在小角度转向和直线行驶两种行驶工况下对操纵稳定性能进行时域仿真研究.理论分析和基于MATLAB的仿真研究表明,4WS技术能使车辆的横摆角速度等状态量保持较小数值.稳定性好.最后,与只有前轮转向(FWS)牵引车列车的稳定性能作对比分析,验证出4WS对列车的高速稳定性和低速机动性有明显的好处.     

Adaptive rollover prevention controller for driver–vehicle systems

In the paper, we propose an adaptive rollover prevention controller for heavy vehicles. At first, a design method for an ideal vehicle model is proposed. The designed ideal vehicle model has the property that good rollover prevention performance can be assured even if the driver steering characteristics vary. If the behavior of the actual heavy vehicle tracks that of the designed ideal vehicle model, rollover prevention can be achieved. Therefore, next, to realize good rollover prevention, we propose an adaptive steering controller. In the heavy vehicle system using the controller, the actual heavy vehicle can track the ideal vehicle model. Then, rollover prevention can be achieved. Finally, to demonstrate the usefulness of the proposed controller, numerical simulations are carried out.     

Lane-keeping assistance control algorithm using differential braking to prevent unintended lane departures

This paper describes a hierarchical lane keeping assistance control algorithm for a vehicle. The proposed control strategy consists of a supervisor, an upper-level controller and a lower-level controller. The supervisor determines whether lane departure is intended or not, and whether the proposed algorithm is activated or not. To detect driver′s lane change intention, the steering behavior index has been developed incorporating vehicle speed and road curvature. To validate the detection performance on the lane change intention, full-scale simulator tests on a virtual test track (VTT) are conducted under various driving situations. The upper-level controller is designed to compute the desired yaw rate for the lane departure prevention, and for the guidance with ride comfort. The lower-level controller is designed to compute the desired yaw moment in order to track the desired yaw rate, and to distribute it into each tire′s braking force in order to track the desired yaw moment. The control allocation method is adopted to distribute braking forces under the actuator’s control input limitation. The proposed lane keeping assistance control algorithm is evaluated with human driver model-in-the-loop simulation and experiments on a real vehicle.