基于CAE技术的某中型卡车司机座椅振动舒适性分析及优化

座椅刚度和阻尼参数的选取,直接影响座椅的乘坐舒适性。采用CAE技术,对某中型卡车司机座椅进行动力学响应分析,并对座椅的弹簧刚度和减振器阻尼参数进行动力学优化,优化后座垫上的加速度峰值大幅降低,取得了比较好的效果。通过平顺性试验验证,优化后的座椅结构在各种车速下,总计权值明显低于原结构。摸索出了一条运用CAE技术对机械式座椅的乘坐舒适性进行分析和优化的途径。     

Ride dynamic evaluations and design optimisation of a torsio-elastic off-road vehicle suspension

The ride dynamic characteristics of a novel torsio-elastic suspension for off-road vehicle applications are investigated through field measurements and simulations. A prototype suspension was realised and integrated within the rear axle of a forestry skidder for field evaluations. Field measurements were performed on forestry terrains at a constant forward speed of 5 km/h under the loaded and unloaded conditions, and the ride responses were acquired in terms of accelerations along the vertical, lateral, roll, longitudinal and pitch axes. The measurements were also performed on a conventional skidder to investigate the relative ride performance potentials of the proposed suspension. The results revealed that the proposed suspension could yield significant reductions in magnitudes of transmitted vibration to the operator seat. Compared with the unsuspended vehicle, the prototype suspended vehicle resulted in nearly 35%, 43% and 57% reductions in the frequency-weighted rms accelerations along the x-, y- and z-axis, respectively. A 13-degree-of-freedom ride dynamic model of the vehicle with rear-axle torsio-elastic suspension was subsequently derived and validated in order to study the sensitivity of the ride responses to suspension parameters. Optimal suspension parameters were identified using the Pareto technique based on the genetic algorithm to obtain minimal un-weighted and frequency-weighted rms acceleration responses. The optimal solutions resulted in further reduction in the pitch acceleration in the order of 20%, while the reductions in roll and vertical accelerations ranged from 3.5 to 6%.     

汽车座椅舒适性的主观和客观评价研究

在对座椅机械结构及人体脊骨生理结构分析的基础上,从主观和客观两方面针对腰托对汽车座椅舒适性影响进行了理论和试验研究。研究表明腰托装置的设计及安装对人体的体压分布有显著影响,设计合理的腰托装置可明显改善汽车座椅的舒适性。     

Analytical description of ride comfort and optimal damping of cushion-suspension for wheel-drive electric vehicles

To provide initial design values of seat cushion and chassis suspension damping for wheel-drive electric vehicles (WDEVs), this paper presents an analytical estimation method and a practical damping parameters design method. Firstly, two formulae of the human body vertical acceleration in terms of the power spectrum density (PSD) and the root mean square (RMS) are deduced for WDEVs. Then, the coupling effects of the key vehicle parameters on ride comfort are revealed. Finally, with a practical example, the damping parameters of the cushion and the suspension are initially designed and analyzed. The results show that when every 10.0 kg increases for motor mass, the optimal damping values of the cushion and the suspension should be reduced by about 15.0 Ns/m and 50.0 Ns/m, respectively. However, the RMS acceleration increases 0.017 m/s² with a decrease of 2.5 % for ride comfort.     

对汽车平顺性评价方法的探讨与建议

首先分析了现行国家标准GB4970-1996<汽车平顺性随机输入行驶试验方法>与国际上通行的人体振动评价标准ISO2631-1997的区别.通过道路试验测量了驾驶员坐垫、靠背和脚部的平移振动以及坐垫的旋转振动共lO个方向的振动.分析发现汽车中人体振动的峰值因子一般小于9;而按照GB4970和ISO2631的试验数据对比表明,GB4970在一定程度上低估了人体振动.分析各方向振动所占的比例发现,坐垫垂向振动、靠背前后振动和坐垫侧倾振动影响最大.最后提出了对汽车平顺性评价方法的建议.     

An Original Feedback Control with a Reversible Electromechanical Actuator Used as an Active Isolation System for a Seat Suspension. Part I: Theoretical Study

This paper provides an overview of a theoretical study of an active seat suspension. The principal objective of this study is to improve ride passenger comfort by reducing transmitted seat acceleration. The seat is represented by a non-linear two degree of freedom model. The system is linearized for small perturbations around the equilibrium. To control the dynamic of the seat suspension, an original feedback control command with a reversible electromechanical actuator is achieved. The synthesis of the regulator is realized on the linearized model of the seat suspension and the root locus method is employed. Stability and robustness characteristics have been studied. Numerical simulations in time and frequency domain show the interests of the regulator and its capability to isolate seat passenger.     

换道操作对智能车辆乘客舒适性的影响研究

乘坐舒适性是决定乘客对智能车辆接受度的重要因素之一。为了提升智能车辆的舒适性,服务智能驾驶控制算法的设计和优化,开展了基于乘客主观感知的实车乘坐舒适性试验,试验中驾驶人驾驶传统车辆执行多次换道操作,获取了60名被试乘客对换道操作的舒适性评价数据,并采集了车辆的运动数据。选取换道时横向最大加速度、回正时横向最大加速度、横向最大加加速度、横向加速度转换幅值以及横向加速度转换频率这5个车辆运动参数作为研究对象。采用二元Logistic回归单因素分析法分析了这5个车辆运动参数对乘坐舒适性的影响,采用接收者操作特征(ROC)曲线分析法为不同晕车易感性的乘客分别确立了这5个车辆运动参数的舒适性阈值,并根据岭回归分析法确定了不同参数对乘坐舒适性的影响权重。结果表明：所选取的5个车辆运动参数对乘坐舒适性具有显著影响,易晕乘客的舒适性阈值小于不易晕乘客的舒适性阈值,在换道过程中,换道时横向最大加速度、回正时横向最大加速度和横向加速度转换幅值是影响乘坐舒适性的主要因素。最后根据车辆运动参数和乘客生理特征参数建立了基于动态时间归整(DTW)和K最近邻(KNN)算法的乘坐舒适性预测模型,该模型对乘坐舒适性的预测准确率为84%,可用于智能车辆控制算法的舒适性判断。     

An Original Feedback Control with a Reversible Electromechanical Actuator Used as an Active Isolation System for a Seat Suspension. Part I: Theoretical Study

This paper provides an overview of a theoretical study of an active seat suspension. The principal objective of this study is to improve ride passenger comfort by reducing transmitted seat acceleration. The seat is represented by a non-linear two degree of freedom model. The system is linearized for small perturbations around the equilibrium. To control the dynamic of the seat suspension, an original feedback control command with a reversible electromechanical actuator is achieved. The synthesis of the regulator is realized on the linearized model of the seat suspension and the root locus method is employed. Stability and robustness characteristics have been studied. Numerical simulations in time and frequency domain show the interests of the regulator and its capability to isolate seat passenger.     

Hybrid modeling of seat-cab coupled system for truck

For the complex structure and vibration characteristics of the seat and cab system of truck, there is no reliable theoretical model for the suspensions design at present, which seriously restricts the improvement of ride comfort. In this paper, a 4 degree-of-freedom seat-cab coupled system model was presented; using the mechanism modeling method, its vibration equations were built; then, by the tested cab suspensions excitations and seat acceleration response, its parameters identification mathematical model was established. Combining the tested signals and a simulation model with the parameters identification mathematical model, a new method of hybrid modeling of seat-cab coupled system was presented. With a practical example of seat and cab system, the parameters values were identified and validated by simulation and test. The results show that the model and method proposed are correct and reliable, and lay a good foundation for the optimal design of seat suspension and cab suspensions to improve ride comfort.     

基于磁流变阻尼器的半主动车辆座椅悬架模糊控制研究

设计基于磁流变阻尼器的半主动车辆座椅悬架系统的模糊控制器。用ADAMS对系统建立三维多刚体动力学模型,用MATLAB设计系统模糊控制器,并联合两者对整个系统进行仿真。仿真和台架试验结果表明,模糊控制策略能使该系统较好抑制垂直振动加速度,提高乘坐的舒适性。     

汽车悬架系统非线性参数时域优化及应用

针对国产某微型轿车,在建立汽车悬架系统5自由度模型和时域路面模型基础上,对悬架系统的线性弹簧和非线性阻尼参数进行了优化。根据优化结果,对悬架系统的刚度和阻尼进行了匹配设计。经试验表明:座椅加速度自谱峰值减小7.4%,加速度均方根值减小19.4%,有效地改善了该车的行驶平顺性,证明时域优化方法对于悬架系统非线性参数优化是可行的。     

An Original Feedback Control with a Reversible Electromechanical Actuator Used as an Active Isolation System for a Seat Suspension. Part II: Experimental Study

From the theoretical study presented in [1], we investigate the experimental feasibility of the active seat suspension to improve ride comfort. The prototype of the reversible electromechanical actuator used in the active seat suspension is presented. First, the kinematic guide with a vertical auto-levelling system is described. Second, the electromechamical actuator and the power drive transmission are presented. It is noticed that the prototype design is achieved with a systemic approach taking into account the industrial constraints. Then, the laboratory experimental setup is described. Several tests are performed on the prototype for model validation and performance purposes. Correct force feedback control in the actuator is verified. The real performances of the active seat suspension on a prototype is investigated for different pertubation inputs. Experimental results clearly show the efficiency of the active seat suspension to improve passenger comfort and demonstrate its feasability.     

An Original Feedback Control with a Reversible Electromechanical Actuator Used as an Active Isolation System for a Seat Suspension. Part II: Experimental Study

From the theoretical study presented in [1], we investigate the experimental feasibility of the active seat suspension to improve ride comfort. The prototype of the reversible electromechanical actuator used in the active seat suspension is presented. First, the kinematic guide with a vertical auto-levelling system is described. Second, the electromechamical actuator and the power drive transmission are presented. It is noticed that the prototype design is achieved with a systemic approach taking into account the industrial constraints. Then, the laboratory experimental setup is described. Several tests are performed on the prototype for model validation and performance purposes. Correct force feedback control in the actuator is verified. The real performances of the active seat suspension on a prototype is investigated for different pertubation inputs. Experimental results clearly show the efficiency of the active seat suspension to improve passenger comfort and demonstrate its feasability.     

Development of an experimental methodology to evaluate the influence of a bamboo frame on the bicycle ride comfort

In the current environment of increased emphasis on sustainable transport, there is manifold increase in the use of bicycles for urban transport. One concern which might restrict the use is the ride comfort and fatigue. There has been limited research in addressing the difficulty in bicycle ride comfort quantification. The current study aims to develop a methodology to quantify bicycle discomfort so that performance of bicycles constructed from bamboo and aluminium alloy can be compared. Experimentally obtained frequency response functions are used to establish a relation between the road input and the seat and rider response. A bicycle track input profile based on standard road profiles is created so as to estimate the acceleration responses. The whole-body-vibration frequency weighting is applied to quantify the perception of vibration intensity so that eventual discomfort ranking can be obtained. The measured frequency response functions provide an insight into the effect of frame dynamics on the overall resonant behaviour of the bicycles. The beneficial effect of frame compliance and damping on lower modes of vibration is very clear in the case of bamboo frame, in turn affecting seat and rider response. In the bamboo frame, because of multiple resonances, the frequency response of the handlebar is smaller at higher frequencies suggesting effective isolation. Further improvements may have come from the joints made from natural composites. Overall, based on the comparative analysis and the methodology developed, bamboo frame shows significant improvement in ride comfort performance compared with the aluminium frame.     

Hybrid modelling and damping collaborative optimisation of Five-suspensions for coupling driver-seat-cab system

For the complex structure and vibration characteristics of coupling driver-seat-cab system of trucks, there is no damping optimisation theory for its suspensions at present, which seriously restricts the improvement of vehicle ride comfort. Thus, in this paper, the seat suspension was regarded as ‘the fifth suspension’ of cab, the ‘Five-suspensions’ for this system was proposed. Based on this, using the mechanism modelling method, a 4 degree-of-freedom coupling driver-seat-cab system model was presented; then, by the tested cab suspensions excitation and seat acceleration response, its parameters identification mathematical model was established. Based on this, taking optimal ride comfort as target, its damping collaborative optimisation mathematical model was built. Combining the tested signals and a simulation model with the mathematical models of parameters identification and damping collaborative optimisation, a complete flow of hybrid modelling and damping collaborative optimisation of Five-suspensions was presented. With a practical example of seat and cab system, the damping parameters were optimised and validated by simulation and bench test. The results show that the model and method proposed are correct and reliable, providing a valuable reference for the design of seat suspension and cab suspensions.     

基于ADAMS/CAR软件的轻型客车悬架系统优化设计

文章以某轻型客车为研究对象,利用ADAMS、Car软件建立了该车虚拟仿真模型,取驾驶员座椅处的垂向加速度的均方根值为目标函数(响应),并基于ADAMS/Insight软件进行了优化;将优化前仿真结果与优化后得到的仿真结果进行了对比,结果表明优化后的仿真结果有效地改善了车辆的行驶平顺性。该研究对在车辆产品开发设计过程中提高其行驶平顺性、降低开发成本及缩短产品研发周期有着一定的指导意义。     

铰接式自卸车悬架系统动力学建模与仿真

建立了一个铰接式自卸车9自由度线性动力学模型，并用Matlab语言编写了基于Simpson算法的仿真程序，来仿真它对路面随机输入的响应，用以计算数种工况下座椅总加权加速度均方根值。仿真结果表明，所建模型能较好地吻合座椅的实际振动，不仅可以正确评估系统的平顺性性能，还可为新型铰接车辆悬架系统、橡胶弹簧的优化设计提供理论和方法支持。     

Influence of tyre–road contact model on vehicle vibration response

The influence of the tyre–road contact model on the simulated vertical vibration response was analysed. Three contact models were compared: tyre–road point contact model, moving averaged profile and tyre-enveloping model. In total, 1600 real asphalt concrete and Portland cement concrete longitudinal road profiles were processed. The linear planar model of automobile with 12 degrees of freedom (DOF) was used. Five vibration responses as the measures of ride comfort, ride safety and dynamic load of cargo were investigated. The results were calculated as a function of vibration response, vehicle velocity, road quality and road surface type. The marked differences in the dynamic tyre forces and the negligible differences in the ride comfort quantities were observed among the tyre–road contact models. The seat acceleration response for three contact models and 331 DOF multibody model of the truck semi-trailer was compared with the measured response for a known profile of test section.     

Decentralized neuro-fuzzy control for half car with semi-active suspension system

In this paper, a decentralized neuro-fuzzy controller has been created in order to improve the ride comfort and increase the stability for half car suspension system, which used the magneto-rheological damper as a semi-active device. Firstly, relative gain array and relative disturbance gain methods have been used for deriving a relation between inputs, disturbances and outputs to select pairing with minimum interaction to design a decentralize controller. Secondary, decentralized neuro-fuzzy controllers for front and rear chassis are designed to predict the required damping force taking the acceleration of the sprung mass and desired acceleration obtained by using pole-placement method as inputs. To predict the control voltage required for producing the force predicted by the controller, the inverse neuro-fuzzy model of MR damper has been designed. Simulation by using MATLAB programs has been created. The results show that the ride comforts and vehicle stability have been improved in comparison with the passive system.