Fundamentals of the fluid mechanics

In this paper, accurate trajectory tracking problem of a surface vehicle disturbed by complex marine environments is solved by creating a finite-time control (FTC) scheme whereby the nonsingular fast terminal sliding mode (NFTSM) and finite-time disturbance observer (FDO) techniques are deployed. Salient features are as follows. By devising an FDO, complex disturbances arising from marine environments can be exactly identified within a short time, in conjunction with the defined NFTSM manifold, and thereby contributing to exact trajectory tracking. Finite-time disturbance observation is completely decoupled from the nominal FTC scheme, and achieves stronger disturbance rejection and faster transient response, simultaneously. Both disturbance observation and trajectory tracking errors can exactly reach to zero in a finite time. Simulation results and comparisons are comprehensively conducted on CyberShip II and demonstrate remarkable superiority of the FTC scheme.

Accurate Trajectory Tracking of Disturbed Surface Vehicles: A Finite-Time Control Approach

Finite- and fixed-settling time differentiators utilizing a nonrecursive higher order sliding mode (HOSM) observer are studied. Fixed convergence time estimation is achieved independent of initial conditions of the differentiation errors. The corresponding convergence/settling times are estimated. The finite- and fixed-time HOSM differentiators’ performance is compared against the Levant recursive one via a hypersonic missile control simulation case study during the missile's terminal phase of flight. A continuous adaptive HOSM control is utilized. The double-layer adaptive algorithm is based on an equivalent control concept and does not allow overestimation of the control gains that mitigates control chattering. The robustness and high-accuracy output tracking in the presence of matched and unmatched external disturbances and missile model uncertainties is demonstrated for both the differentiators and the controller.

Hypersonic Missile Adaptive Sliding Mode Control Using Finite- and Fixed-Time Observers

Finite- and fixed-settling time of real-time differentiators utilising a higher-order sliding mode (HOSM) observer based on both non-recursive and recursive algorithm formulations are studied using constant observer gains. Fixed convergence time estimation is achieved independent of initial conditions of the differentiation errors. The corresponding convergence/settling times are estimated. The HOSM differentiators are compared with the ideal differentiation formulation and MATLAB's differentiator. The analysis incorporates input noise to demonstrate via simulations the improved performance for real-time noisy input signals.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-cta.2016.1256

Finite- and fixed-time differentiators utilising HOSM techniques

This report is a summary of selected national transportation statistics from a wide variety of government and private sources. Included are cost, inventory, and performance data describing the passenger and cargo operations of the following modes: air carrier, general aviation automobile, bus, truck, local transit, rail, water, oil pipeline, and gas pipeline. The report includes basic descriptors of U.S. transportation, such as operating revenues and expenses, number of vehicles and employees, vehicle miles and passenger miles, etc. A supplementary section includes Transportation and the Economy and Energy in Transportation Energy in Transportation is divided into four parts: Energy Consumption, Energy Transport, Energy Intensiveness, and Energy Supply and Demand. Also included are the operating costs of automobiles of different sizes. In this edition, the edition, the selected data cover the period 1971 through 1981/1982.

National transportation statistics

Both steering angle and sideslip angle are important states for vehicle handling and stability control. Instead of directly measuring these angles, indirect estimation of these states will provide a cost-effective way for the implementation of vehicle control systems. In the past, model-based methods have been proposed to estimate the sideslip angle with the measured steering angle. In this paper, a novel observer design is presented for simultaneous estimation of vehicle steering angle and sideslip angle so that the estimation of sideslip angle does not require the measurement of steering angle and the estimate of steering angle can also be used for other purposes, such as automatic steering control, steering system fault diagnosis, and driving performance monitoring. To enable this observer design, the Takagi–Sugeno (T–S) fuzzy modeling technique is applied to represent the vehicle lateral dynamics model with nonlinear Dugoff tyre model and time-varying vehicle speed. A T-S observer is then designed to simultaneously estimate the steering angle and sideslip angle with the measurements of yaw rate and vehicle speed, and is designed to be robust against parameter uncertainties and unknown inputs. The conditions for designing such an observer are derived in terms of linear matrix inequalities (LMIs). Experimental results are used to validate the effectiveness of the proposed approach. The results show that the designed observer can effectively estimate steering angle and sideslip angle despite the variation of vehicle longitudinal speed.

A Novel Observer Design for Simultaneous Estimation of Vehicle Steering Angle and Sideslip Angle

https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1204&context=eispapers1

Disturbance observer based Takagi-Sugeno fuzzy control for an active seat suspension

This paper is aimed at developing a computationally efficient approach to simulate the vertical dynamic behavior of vehicle–track coupled system. With the finite element method, the car body, bogies, and rail are modeled as Euler beams supported by springs and dashpots, which can investigate the influence of flexibility of the vehicle on structural dynamic response. By a variant of component-mode synthesis (CMS), the degrees-of-freedom (DOFs) within the substructures are condensed and the two substructures are coupled through nonlinear Hertzian theory. Although the system matrix is updated and factorized during the calculation, the total computational efficiency is significantly improved due to the much smaller size of the equations of motion and direct solution algorithm instead of iterative procedure. Compared with an existing model, the accuracy and efficiency of the method are investigated. Application of the model is shown by numerical example.

A Condensation Method for the Dynamic Analysis of Vertical Vehicle–Track Interaction Considering Vehicle Flexibility

The trade-off between handling stability and ride comfort is a disadvantage for the bus fitted with passive suspension due to its high center of gravity and heavy load. A novel suspension configura...

Improvement of both handling stability and ride comfort of a vehicle via coupled hydraulically interconnected suspension and electronic controlled air spring

This study presents a technique that uses a model reduction method for the dynamic response analysis of a beam structure to a moving load, which can be modeled either as a moving point force or as a moving body. The nature of the dedicated condensation method tailored to address the moving load case is that the master degrees of freedom are reselected, and the coefficient matrices of the condensed model are recalculated as the load travels from one element to another. Although this process increases computational burden, the overall computational time is still greatly reduced because of the small scale of motion equations. To illustrate and validate the methodology, the technique is initially applied to a simply supported beam subjected to a single-point load moving along the beam. Subsequently, the technique is applied to a practical model for wheel-rail interaction dynamic analysis in railway engineering. Numerical examples show that the condensation model can solve the moving load problem faster than an analytical model or its full finite element model. The proposed model also exhibits high computational accuracy.

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Bangji Zhang

Papers

A Novel Observer Design for Simultaneous Estimation of Vehicle Steering Angle and Sideslip Angle

Disturbance observer based Takagi-Sugeno fuzzy control for an active seat suspension

A Condensation Method for the Dynamic Analysis of Vertical Vehicle–Track Interaction Considering Vehicle Flexibility

Improvement of both handling stability and ride comfort of a vehicle via coupled hydraulically interconnected suspension and electronic controlled air spring

Model Reduction Technique Tailored to the Dynamic Analysis of a Beam Structure under a Moving Load