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Abstract: The dynamics of a new concept of a high-speed cable car developed for fast urban transport have been analysed and improved via active control. A mathematical model, which takes into account all the mechanical complexities of a coupled cable-vehicle dynamic system, has been built. From the complete FE cable model, a simpler model has been derived to be used with the vehicle model in the design of control strategies of the active suspension. In order to validate the results experimentally, a reduced scale quarter vehicle test rig has been built simulating the real time cable behaviour by means of a stiffness controlled hydraulic actuator [ABSTRACT FROM AUTHOR]

This paper presents a computer-controlled suspension design for tractors and semi-trailers cabs and driver's seats. Two separate models representing the vehicle with a cab suspension and the seat with an operator modeled as a lumped mass system are presented. The vehicle is represented by an 8 degrees-of-freedom (DOF) model, which includes a 3-axle tractor semi-trailer and a separated cab with suspensions. The seat/operator system is modeled by a 6 DOF model to simulate the vertical dynamic response of the driver including the seat suspension. The cab is supported by a set of controllable suspensions at both of the front and rear ends of the cab. The seat is attached to the floor of the cab by another controllable suspension. Each controllable suspension is modeled by a set of linear spring and non-linear damper whose coefficient is time dependent. First, a sky-hook based semi-active controller was designed to seek optimum cab suspension. Then, the second state controller was used with the cab's velocity and displacement as input to minimize the parameters of the seat/operator model. The seat suspension parameters were optimized to yield the best ride quality under the prescribed input road conditions. The ride comfort is measured using the absorbed power under stochastic road excitation. [ABSTRACT FROM AUTHOR]

Ride and handling simulation of a heavy off-road military vehicle was simultaneously performed using DADS software. A non-linear vehicle simulation model, complete with a total of 66 degrees of freedom, was developed. After adding constraints, joints and a driver model, 14 unconstrained degrees of freedom remained. Ride comfort and handling/stability evaluations were combined in a single simulation run by driving the vehicle over Belgian paving whilst simultaneously performing a double lane change handling manoeuvre. The aim of the study was to determine the "best" spring and damper characteristics for ride comfort and handling/stability respectively. These characteristics will be used to design a semi-active, hydropneumatic spring-damper, able to switch both spring and damper characteristics electronically between two discrete values. The simulation results indicated that, for best ride comfort, the suspension natural frequency should be in the region of 0.6 Hz while the damper characteristic should be reduced to a value between 20 and 50% of the baseline damper value. For best handling and stability, a suspension natural frequency of 2 Hz is required while the baseline damping should be doubled. [ABSTRACT FROM AUTHOR]

The objective of this paper is to describe the simulation of a vehicle, paying special attention to behaviour at low velocities. The main aim of this research is to simplify the development process of special automotive controllers, and to enable the engineer to use modern CAE techniques to reduce expensive and sometimes dangerous driving tests. [ABSTRACT FROM AUTHOR]

First, a driver model is presented which, conceived as an information processing unit, reproduces human driving behaviour and controls the vehicle up to its physical limits. Second, a new issue is introduced in the subjective assessment of vehicle handling characteristics. It is shown that subjective ratings are essentially based on the effort a driver has to summon up to successfully solve the driving task. Combining the driver model and the effort issue generates a dynamic rating driver model. This rating driver model may be used together with vehicle models in simulation for vehicle handling design. [ABSTRACT FROM AUTHOR]

The paper discusses some of the common speed and steering control strategies of drivers for negotiating curved roads under normal, obstacle-free driving conditions. An analysis is given of the dynamic behaviour of the driver-vehicle system for two typical strategies. A driver model is developed to take into account the application of steering and speed control before approaching a curve and during driving on curved roads. The driver's anticipatory speed-control is based on the desired lateral acceleration and estimated maximum curvature of the road ahead. The well-known two-level model is adapted for describing the steering activity of the driver. The primary control of steering is anticipatory tracking of the road-curvature previewed at a look-ahead distance. It is assumed that the driver's mental model for anticipatory steering is based on a simple, linear and non-adaptive vehicle model assuming a vehicle driving with constant forward speed. A non-linear model with variable forward speed represents the actual vehicle. When both steering input and speed control using brake/throttle are applied simultaneously the driver's anticipatory steering estimate leads to tracking errors. The driver's compensatory steering input for reducing tracking errors uses feedback of error in lateral displacement at a near-field viewpoint of the driver. The results of analysis of the driver-vehicle system demonstrate the significant influence of the driver's internal model and control strategies on the overall performance of the driver-vehicle system. [ABSTRACT FROM AUTHOR]

The prediction of driver behaviour by means of models is a research topic almost as long as models of vehicles were presented as tools for vehicle development. The principal motivation was always the benefit of computer simulation as an instrument for a prospective assessment of vehicle developments. Several fields of industrial application are presented and future developments outlined. [ABSTRACT FROM AUTHOR]

Simulations of closed-loop manoeuvres where the driver is modelled in a vehicle-road environment axe of increasing importance in car development. To be able to investigate manoeuvres with large local deviations from a desired road trajectory the 2-level standard driver model, which is based on previewed steering, is extended by a 3rd level which initiates a smooth transition to the road trajectory. The corresponding control design is based on the two-wheel vehicle model and the sliding control technique, and more over it can be adapted to different steering intensities and driving situations. The simulation results are based on a complex 3D vehicle model and consider different tyre-road friction conditions. An obstacle avoidance manoeuvre and the entering of a curve (with clothoide) with a μ-low section in the circular part prove the quality of this 3-level approach. [ABSTRACT FROM AUTHOR]

An existing state—space based numerical method (see Reference [1]) to simulate vertical dynamic interaction between a rolling train and a railway track has been improved and extended. The modified method allows for non—linear track model properties and flexible vehicle model components. Track model properties are separated into linear contributions corresponding to a non—loaded track configuration and increments which are state—dependent. Linear finite element models represent the train and the track modelled as separate components. Model reduction techniques are employed for computational efficiency. State—dependent track model properties tire accounted for by applying counter—acting state—dependent forces to the corresponding nodes of the linear track model. The train/track simulations are carried out in the time—domain. The need for a state—dependent track model is discussed with respect to laboratory and field measurements. [ABSTRACT FROM AUTHOR]

Examines the validation of a nonlinear automotive seat cushion vibration model. Description of the vertical vibration compliance of an automotive seat; Inclusion of the nonlinear stiffness and damping effects of the model; Mimicry of the properties of open cell foams used in the construction of a seat cushion.

Examines a computational procedure for non-linear dynamic analysis of vehicles. Interest on the accurate simulation of the dynamic behaviors of vehicles; Necessity of the application of large mechanical models for the correct information; Presentation of the applicability of the procedure by the use of a bus finite element model.

Examines the feedback controls for an active preview suspension applied to a half-car model. Details of the requirements of measurements relative to the road; Arbitrariness of the front and rear spring rates; Effects of the preview on the performance.