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The capability of avoiding static obstacles independently is the premise for air cushion vehicle (ACV) operating safely. In this article, an ACV collision avoidance control based on improved artificial potential field method is designed as auxiliary operating system to ensure safe navigation of ACV. It builds mathematical model of the ACV and searches the data of static obstacles. Besides, the collision...
During the launching of the AUV especially in air-launching, the water entry problem is inevitable. The AUV will stir the flow field of surrounding fluid during the moving into water, while the fluid will act a strong force on the AUV in return, which may cause trajectory deflection problems or damage to their structure and inner components in severe cases. The water entry experiment of full-size...
In this paper, we employ a dynamics modeling method for investigating a multi-body dynamics system consisting of an unmanned surface vehicle (USV), an umbilical cable (UC), and an autonomous underwater vehicle (ROV). The ROV, which is towed by a UC for the purposes of exploration or mine hunting, is modeled with a Six-Degree-of-Freedom (6-DOF) equation of motion that reflects its hydrodynamics characteristics...
In this study, virtual planar-motion-mechanism (PMM) tests in pure sway motion at constant forward speed are carried out to determine the sway added mass values of a 6:1 prolate spheroid. Added mass values are obtained by solving the Euler equations and the Reynolds Averaged Navier-Stokes (RANS) equations across a range of frequencies and depths. The effect that distance from the surface and radiation...
In this paper, the conceptual design with integrating motion control and considering the cross current was applied to establish a submarine motion simulator, where the path motion stability is evaluated. The methods used to construct the simulator include the standard navigation approach by applying the LOS algorithms and PD control Euler-Rodriguez quaternion for conversion between submarines motion...
This paper presents the motion simulation of an autonomous underwater helicopter (AUH), a new type of underwater vehicle proposed by Zhejiang University. In order to determine whether its controllability meets the design requirements, a singularity-free unit quaternion stable control method is used for simulating the AUH performance in MATLAB, including its force and trajectory under different types...
In order to analyze the dynamic performance of a Remotely Operated Vehicle (ROV) during mission like ship hull inspection, it is necessary to establish the 6 degree-of-freedom equations of motion considering well modeled hydrodynamic force acting on a ROV. Typically, the hydrodynamic force is the model by polynomial functions and those coefficients are obtained by captive model tests or empirical...
The paper considers a reference-based control system for heaving wave energy converters. The proposed controller comprises two parts: lower level part (LLP) and higher level part (HLP). The HPL generates the buoy's velocity reference with the objective to maximize the power absorption with the constraints in the maximum control force and the power take-off device's utilization index. The index is...
A Complex Conjugate (CC) control is implemented with a Proportional-Derivative (PD) controller for WEC devices to improve and optimize power absorbed. Traditionally, CC control has not been realizable due to actual implementation that requires acceleration feedback or exact term cancellation. For the PD implementation, only the stiffness term is employed to modify the impedance and achieve resonance...
This paper addresses the problem of designing a control that maximizes the harvested energy of a wave energy converter, in the presence of displacement constraints. The feasible displacement range is split into two segments. In the first segment (the inner segment), an unconstrained optimal control is used. In the outer segment, a constraint control is used. For the unconstraint control in the inner...
This paper considers the application of finite-time control to a Cucker-Smale flocking model of autonomous agents with collision avoidance. A mathematical expression for the upper bound on the flocking time is derived. Previous results without considering collision avoidance showed that the flocking time decreases as the number of robots in the flock increases, which is counter-intuitive. We showed...
Due to the complexity of the mathematical and computational reproduction of collision movements performed by solids objects in the real world, alternately a common approach is to use dynamic models compound of elastic (spring) and dissipative (damper) forces with the theory of rigid bodies. In this paper, the modeling of translational and rotational movement of a solid cube in free fall colliding...
Unmanned Aerial Vehicles (UAVs) with different configurations exist to supply requirements for diverse applications. One of them is the tailsitter that gathers complementary advantages from Vertical Takeoff and Landing (VTOL) and fixed-wing UAVs. In this paper, we present a new design of a tailsitter UAV, named AVALON (Autonomous VerticAL takeOff and laNding). This UAV is composed of typical actuators...
This paper develops a linear parameter varying(LPV) based robust model predictive control(MPC) method for a multi-vectored airship, the speed of the forward flight channel is considered. The nonlinear model of the airship is introduced with kinematics and dynamics. Then, in order to obtain the LPV models, the small perturbation linearization method is used. After that, the higher order singular value...
In this paper, a completely numerical simulation model of a tilt rotor helicopter is established. Based on the hierarchical and modular modeling principles, the whole simulation model is finally realized on the Simulink platform. Then a sliding mode variable structure controller based on expansion state observer (ESO) is designed in order to realize the attitude control of this nonlinear and strong...
This paper presents a method for estimating object poses based on force sensor information using a particle filter. Autonomous robots often face uncertainty of measurement of object position when they manipulate objects. Related studies dealing with uncertainty in manipulation mainly focused on motions while grasping objects. In contrast, however, a non-grasp contact motion can be advantageous because...
Sea-crossing bridges are exposed to great waves. The wave induced dynamic effect on the structural response of the pier was carefully studied in this paper. The pier of Pingtan Strait railway bridge was taken as the example structure. The modal and dynamic response of the example pier under regular wave loadings were carried out using finite element software USFOS. The dynamic and static response...
In this paper, the stability problem of bilateral tele-operation systems with data sampling and communication time delays is considered. Two buffers are introduced in the bilateral teleoperation control framework to deal with the issue that the information transmitted between the master and slave sides suffer from time-varying delays. The mathematical model of bilateral teleoperation systems based...
As the air bearing flying height (a few nanometer levels) and the deformation of suspensions (micro-or millimeter level) run at two different scales, a dual-scale model for head disk interface (HDIs) has been proposed to analyze the unloading behavior of a subambient pressure slider. With the scheme developed, the unloading process can be simulated efficiently. The nonlinear vibrations of the air...
In order to accurately simulate vehicles' running states of lane changing and more effectively reflect its characteristics, based on the driving experience, this paper introduced three changing rules and their corresponding lane changing benefits and safety factors, and summarized the lateral and longitudinal motion of vehicles as the interaction result between lane changing benefits and safety factors...
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