Papers by Keyword: Longitudinal Dynamics

Abstract: The paper originally investigates the influence of the admitted ranges of slow-acting filling time of brake cylinder on longitudinal dynamics of freight trains, using experimental air pressure data obtained in tests on filling characteristics. Mechanical and pneumatic models are summarized and numerical simulations were performed for a train composed of six wagon train, in different filling characteristics configurations. The results reflect significant effects on in-train forces values, while evolution and disposition of compression and tensile forces between neighbored vehicles in the long of the train are also affected.

Abstract: A stability estimation approach is proposed to support complementary stability criterion design in vehicle planar motion. The comprehensive effect of tangential force and axle load transfer on tire cornering characteristics is considered corresponding to the longitudinal dynamics effects. The effectiveness of different stability concept is discussed in terms of the physical meaning of state variables in 3DOF differential systems. Based on the sense of technical stability, the 3DOF model is simplified according to longitudinal dynamics characteristic within definite observation time interval. The central equilibrium points continuum properties of the simplified model can be used to estimate the vehicle behavior in planar motion.

Abstract: The objective of the present work is to evaluate the static and dynamic stability of the Flying Wing Unmanned Aircraft Vehicle (UAV) model using the Tornado software. The longitudinal and the lateral-directional aerodynamics were studied using the model with incompressible flow, asymmetric, conditions. The stability coefficients were calculated and give proof that the aircraft is statically stable. Using the stability coefficients, the longitudinal and lateral-directional equations of motion were written to evaluate the dynamic stability of the vehicle. Good flying qualities were obtained, rating in Level 1 for the Cooper and Harper scale.

Abstract: To solve the vehicle longitudinal dynamics problems of driving control, this paper takes the electric off-road vehicle with separated driven axles as the research object. An 8-DOF system dynamics model of vehicle with independently driven front and rear wheels was built by using the MATLAB/Simulink software. The recognition algorithm of the separated road surface was proposed and corresponding driving control strategy was researched. The simulation results show that the proposed drive control strategy can adapt to separated road surface, and ensure vehicle driving safely in accordance with the driver's intention.

Abstract: According to the principle of the train longitudinal dynamics, the heavy haul longitudinal dynamics nonlinear model is established to analyze the influences of the load distribution pattern and the locomotive position on train longitudinal dynamics. The study of this paper is divided into two parts. The first, train model is composed by a locomotive and six trailers, researching the influences of the load distribution pattern on train longitudinal dynamics, the analysis results show that, the best load distribution pattern is the descending from head to tail of the train, in this case, the coupler force is minimum, and the train longitudinal dynamics is best; the second, train model is composed by two locomotives and five trailers, researching the influences of the position of the locomotive on train longitudinal dynamics. The analysis results show that, if the first locomotive is at the head of the train, then the second locomotives best position is at the end of the train, in this case, the coupler is minimum. But the train longitudinal dynamics performance is the worst with two locomotives are located in the head.

Abstract: The purpose of this paper is to simulate flight path of Boeing-747 for longitudinal motion at selected flight conditions using 6 DoF (Degrees of freedom) nonlinear equations with MATLAB and SIMULINK. The equations are solved to compute the flight path within 100 seconds of Boeing 747 at three flight conditions, for cruise flight with different Mach numbers at same altitudes, and then Mach number at high altitude with MATLAB programming (ode45). Simulation results for different conditions are presented and analyzed.

Abstract: Controlling the flight of Micro Aerial Vehicles (MAV) is a highly challenging task, mostly due to nonlinearity of their models and highly varying longitudinal and lateral derivatives coefficients [. As such, it requires a proper form of robust control. The demand for such control is very high, as it is required in many applications. The following paper presents the application of Unfalsified Control Theory developed by Michael G. Safonov [1, 2, 6, . This interesting approach is based on the adaptive switching control, and does not require any previous knowledge of the controlled plant. The controlled dynamics is decoupled due to longitudinal and lateral motion of the Bell 540 single-delta wing micro aerial vehicle. The work involves design and simulation of the proper robust controller. The simulation is based on already obtained nominal model of the Bell 540 vehicle [. The developed controllers were proved to be efficient, based on performed calculations and simulation in Matlab.

Abstract: A Continuous Sliding-Mode Controller (CSMC) using integral action is implemented to control the response of the longitudinal dynamics of an aircraft. Model-following of the pitch rate q is obtained through this method. Asymptotic regulation achieved by integral control has its downsides because transient performance is reduced. A solution to this problem consists in using the integral action only “conditionally”, thus eliminating the performance downgrade. Finally a comparison will show how Sliding-mode control will minimize the chattering phenomenon and also reduce “integrator windup” problem, thus minimizing the loss of transient performance.

Abstract: Regulating line with the optimum fuel economy performance is investigated based on the universal characteristic map of the engine equipped on the snowmobile. The engine is supposed to run in a range near the optimum fuel economy performance regulating line with CVT speed regulating control. The dynamic model of the snowmobile is proposed, and simulation with Simulink is investigated. Though acceptable deviation occurs when compared with experimental results, reliability is validated for the model. With further amendments of the model, such as a further consideration of the slip state of the CVT when launching the snowmobile, the model can be applied to the practical engineering as an effective design tool.

Abstract: The traction tonnage has important effect on train longitudinal impact. An integrated model of train longitudinal dynamics was established based on simulation and test results. The effect of the traction tonnage on train longitudinal dynamics was investigated through modeling different types of heavy-haul trains. The model was validated by using measured longitudinal force time histories from on-track tests. Case study shows that the traction tonnage has significant influence on train longitudinal impact; Train longitudinal force increases with traction tonnage. The relationships between the maximum coupler forces (including tensile and compressive forces) and traction tonnage were obtained with the least square method for cases of train under emergency baking and release condition. The established train longitudinal dynamics model provides a platform for car body and coupler structure optimization and train control.