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A series of work for distributed dynamic load identification is investigated in this paper considering unknown-but-bounded uncertainties in the aircraft structure. To facilitate the analysis, the complicated rudder structure is simplified to a plate structure based on the robust equivalence principle of mechanical property under multi-cases of flight environments. Aiming at the plate structure, a time domain–based model for distributed dynamic load identification is established through the acceleration response measured by sensors. Among them, the spatial distributed load is approximated by Chebyshev orthogonal polynomials at each sampling time, and load boundaries can be calculated by the Taylor-expansion-based uncertain propagation analysis. As keys to improve the reliability of recognition results, the optimization process for sensor placement is constructed by the particle swarm optimization algorithm, taking the robustness evaluation index and sensor distribution index into consideration. The validity and the feasibility of the proposed methodology are demonstrated by several numerical examples, and the results reveal that designer can make a rational tradeoff choice among the cost of sensor placement and the performance of load identification in a systematic framework.

This work investigates the challenge of steering system positional control with a specific view to autonomous driving. Positional control of steering systems has, until now, been under-researched to meet the performance scope of fully autonomous driving. As such, a parallel axis steering gear, found in luxury vehicles, is the target system for this work. The focus of this thesis is a model-based approach to steering control. Moreover, these models are developed using measurement based techniques, thereby determining the main factors reproducing the system behaviour.

When conducting the overall assembly design of the rudder compartment, a detailed optimization analysis of its assembly process is required. In this paper, the assembly process problem of the rocket rudder compartment is regarded as a combinatorial optimization problem of the assembly sequence, and the ant colony algorithm is adopted to optimize and analyze the assembly process of the rudder compartment. The interference matrix is used to deduce the feasible assembly schemes of the components in the rudder compartment. By adding key constraint conditions such as assembly position, assembly tool, and assembly direction, the path pheromone is updated to carry out the process planning of the assembled components. By setting specific parameters and verifying through experiments, the optimal assembly process sequence of the rudder compartment is obtained. The advantages and disadvantages of the proposed method are summarized.

The proper evaluation of the Rudder–Propeller interactions is mandatory to correctly predict the manoeuvring capability of a modern ship, in particular considering the commonly adopted ship layout (rudder often works in the propeller slipstream). Modern Computational Fluid Dynamics (CFD) solvers can provide, not only the performance of the whole system but also an insight into the flow problem. In the present paper, an open-source viscous flow solver has been validated against available literature experimental measurements in different conditions. After an extensive analysis of the numerical influence of the mesh arrangement and the turbulent quantities on the rudder provided forces, the study focused its attention on the forces generated by the rudder varying the propeller loading conditions and the mutual position between the two devices. These analyses give a hint to describe and improve a commonly-used semi-empirical method based on the actuator disk theory. These analyses also demonstrate the ability of these numerical approaches to correctly predict the interaction behaviour in pre-stall conditions with quite reasonable computational requests (proper also for a design stage), giving additional information on the sectional forces distribution along the span-wise rudder direction, useful to further develop a new semi-empirical rudder model.

X-rudder UUV is a typical redundant control system with high reliability and high control difficulty. This article researches the reconfigurable control allocation technology of X-rudder UUV control, analyzes and sorts out typical fault types of X-rudder UUV, and designs a reconfigurable control allocation algorithm without changing the high-level control law. In the case of partial failure of the rudder surface, the remaining rudder surface is used to complete the movement of UUV, improving the robustness of UUV to faults and damage. The effectiveness of the proposed fault-tolerant control allocation method is verified by simulation.

Byun, T.Y.; Lee, K.W.; Kim, J.W., and Kim, M.C., 2021. Comparative study on the performance of a twisted rudder with wavy configuration. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 569–573. Coconut Creek (Florida), ISSN 0749-0208. Because of recent serious human injuries and marine pollution caused by ship accidents, interest in maneuverability of ships has been increasing. In addition, because the International Maritime Organization (IMO) mandates the adoption of Energy Efficiency Design Index (EEDI), which is a total carbon dioxide regulation system, the demand for eco-friendly ships has increased. The energy saving device in the stern direction based on the propeller is called a post device, and most post devices are based on rudders. Various special rudders have been introduced to reflect this interest in eco-friendliness and steering safety. In this study, to confirm the ship applicability of a twisted rudder with wavy configuration, we reviewed the ship resistance, self-propulsion, and maneuverability. The target ship for analysis and experiment was a KRISO container ship, and the performance of Wavy Twisted Rudder (WTR) was compared and verified with a fishtail rudder, which is an existing special rudder. A Computational Fluid Dynamics (CFD) analysis was conducted using Star CCM+ ver.11.02, and it was computed using the Reynolds-Averaged Navier-Stokes (RANS) equation as the governing equation for turbulent flow analysis around the hull. The verification result revealed that the maneuverability of the proposed rudder was slightly lower than that of the existing special rudders. However, the maneuverability sufficiently satisfied the IMO standards and demonstrated improved results in terms of efficiency.

In this study, the berthing and unberthing performances of a single-propeller and single-rudder inland container ship with a flapped rudder and bow thruster were investigated using free-running model tests. A navigation method was used for the tests to adjust the bow thruster, so that the heading remained parallel to the pier and the ship berths or unberths while sailing in oblique conditions. As a result, the proposed method enables the target ship to berth or unberth in shallow water with h / d = 1.5 , where h is the water depth and d is the ship draft. Such a free-running test using the navigation method is useful for evaluating the berthing and unberthing performance of single-shaft ships with a bow thruster. In addition, a bow thruster impeller revolution controller was incorporated into the maneuvering simulation model proposed by the authors, and berthing calculations were performed. The calculation results were compared with free-running test results for validation. These results are consistent with the free-running test results with practical accuracy.

The complex interaction flow field induced by jet flow and supersonic free stream about large slenderness ratio missile including compound trajectory jet and rear rudder is numerically studied. Two types of cold jet flow parameters conversion method is researched by RANS. The detailed multiple jet interaction flow field and aerodynamic results are compared with binary hot jet flow. The research results show that several kinds of shock wave, vortex structures are generated due to interaction of multiple lateral trajectory jet flow with rudder. The jet flow affects the pressure distribution in the downstream area. There are obvious differences between two types of cold jet flow parameters. Consistent mass flow ratio conversion simulation result, named as cold 1 is more close to the simulation result of hot jet flow when compared with total temperature of 293.15K conversion simulation result, named as cold 2.

The mechanism and principles of the impact of nonlinear elements on the dynamic characteristics of the folding rudder structure under different states are investigated in this paper. A spring element dynamic modeling method is proposed, which uses uniformly distributed parallel spring elements to represent the contact stiffness nonlinearity caused by interface errors in the folding rudder. A stiffness simulation analysis model of the folding rudder under different states is established, and modal simulation analysis and experimental validation are conducted. The experimental validation results show that the relative error in the inherent frequency between the simulation analysis results and the experimental results for the folding rudder model under different states is less than 6%, indicating that the model can effectively replicate and predict the dynamic characteristics of the folding rudder. Therefore, a stiffness model that can accurately predict the dynamic characteristics of the folding rudder in different states is established. The results show that the inherent frequency of the folding rudder structure gradually increases with the increase in the equivalent stiffness of the spring elements and eventually stabilizes. Using the method of spring element equivalence to model the contact stiffness at the interface can effectively replicate the contact nonlinearity of the gaps in the folding rudder structure under different states. Moreover, increasing the number of equivalent springs on the contact surface improves the prediction accuracy of the folding rudder’s dynamic characteristics.

The joint clearance of rudder loop has a significant impact in achieving the high-precision attitude control of aircraft. This study proposed a novel revolute joint clearance contact model considering surface topography. Such a model identified that the impact dynamic characteristics were significantly influenced by parameters such as contact speed, roughness, and curvature radius of asperities. The dynamic model of the rudder loop was based on the Lagrange equation and the contact model of revolute joint clearance. The results indicated that rudder angle error, contact force, and impact frequency nonlinearly increased along with the increase of motor speed. The increment of joint clearance caused increased rudder angle error and contact force, but a decreased impact frequency. An increase in contact surface roughness decreased the contact force and exerted insignificant effects on rudder angle and impact frequency. To verify the dynamic model, a dynamic characteristic test rig of rudder loop was established. This study can improve the dynamic analysis accuracy of the rudder loop with clearance and provide a solid theoretical basis for solving the high-precision control of the discontinuous structure.