共查询到20条相似文献，搜索用时 31 毫秒
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Nonlinear path-following control of an AUV 总被引：3，自引：0，他引：3
A new type of control law is developed to steer an autonomous underwater vehicle (AUV) along a desired path. The methodology adopted for path-following deals explicitly with vehicle dynamics. Furthermore, it overcomes stringent initial condition constraints that are present in a number of path-following control strategies described in the literature. Controller design builds on Lyapunov theory and backstepping techniques. The resulting nonlinear feedback control law yields convergence of the path-following error trajectory to zero. Simulation results illustrate the performance of the control system proposed. 相似文献
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Antonelli G. Caccavale F. Chiaverini S. Villani L. 《Oceanic Engineering, IEEE Journal of》2000,25(3):399-413
In this paper, the problem of tracking a desired motion trajectory for an underwater vehicle-manipulator system without using direct velocity feedback is addressed. For this purpose, an observer is adopted to provide estimation of the system's velocity needed by a tracking control law. The combined controller-observer scheme is designed so as to achieve exponential convergence to zero of both motion tracking and estimation errors. In order to avoid representation singularities of the orientation, unit quaternions are used to express the vehicle attitude. Implementation issues are also considered and simplified control laws are suggested, aimed at suitably trading off tracking performance against reduced computational load. Simulation case studies are carried out to show the effectiveness of the proposed controller-observer algorithm. The obtained performance is compared to that achieved with a control scheme in which the velocity is reconstructed via numerical differentiation of position measurements. The results confirm that the chattering on the control commands is significantly reduced when the controller-observer strategy is adopted in lieu of raw numerical differentiation; this leads to lower energy consumption at the actuators and increases their lifetime 相似文献
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程国胜 《数字海洋与水下攻防》2019,2(1):86-94
工程中矢量物理量的测量,例如水中目标的磁场、电场的测量,通常测量传感器的姿态角是任意或随机的,因此需要对传感器平台的姿态角进行测量,并由此将矢量物理量的测量数据修正到确定的参照坐标系。 分析了文献中通常使用的修正算法,即根据传感器平台姿态角测量值直接引用欧拉角旋转变换公式,分析表明这一算法存在原理性误差。 在此基础上,推导出了合理的变换计算式,可以直接应用在任意姿态下矢量物理量的测量数据修正计算,以及类似的坐标变换计算中。 相似文献
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The formation control problem for underactuated unmanned surface vehicles (USVs) is addressed by a distributed strategy based on virtual leader strategy. The control system takes account of disturbance induced by external environment. With the coordinate transformation, the advantage of the proposed scheme is that the control point can be any point of the ship instead of the center of gravity. By introducing bio-inspired model, the formation control problem is addressed with backstepping method. This avoids complicated computation, simplifies the control law, and smoothes the input signals. The system uniform ultimate boundness is proven by Lyapunov stability theory with Young inequality. Simulation results are presented to verify the effectiveness and robust of the proposed controller. 相似文献
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In this paper, a robust path following control law is proposed for a deep-sea manned submersible maneuvering along a predeterminated path. Developed in China, the submersible is underactuated in the horizontal plane in that it is actuated by two perpendicular thrusts in this plane. The advanced non-singular terminal sliding mode （NTSM） is implemented for the design of the path following controller, which can ensure the convergence of the motion system in finite time and improve its robustness against parametric uncertainties and environmental disturbances. In the process of controller design, the close-loop stability is considered and proved by Lyapunov＇ s stability theory. With the experimental data, numerical simulations are provided to verify the control law for path following of the deep-sea manned submersible. 相似文献
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Unmanned underwater vehicles (UUVs) typically operate in uncertain and changing environments. Globally convergent Lyapunov-based parameter-adaptive controllers for six-degree-of-freedom position and attitude trajectory-tracking control of astable UUVs have been successfully derived and applied. We propose an efficient adaptive-control scheme for UUVs based on existing parameter-adaptation schemes popular in the robotics literature. Specifically, we customize bounded-gain-forgetting composite adaptation, which utilizes information about both the tracking and model-prediction errors to yield faster parameter convergence than the traditional tracking-error-based (TEB) adaptation. Hence, better transient behavior of tracking errors is achieved by using fewer control efforts in most cases. We show the effectiveness of applying the suggested adaptation scheme on UUVs through simulation. 相似文献
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Shipborne GPS attitude determination during MMST-93 总被引：1，自引：0，他引：1
Lachapelle G. Cannon M.E. Lu G. Loncarevic B. 《Oceanic Engineering, IEEE Journal of》1996,21(1):100-104
The attitude parameters of a ship underway were measured using a configuration of four 10-channel NovAtel Model 951 narrow-correlator-spacing receivers. These C/A code receivers have output rates of up to 10 Hz and maintain effective carrier phase lock under relatively harsh ship dynamics. The attitude parameters are calculated independently at each epoch using differential carrier phase measurements, carrier phase ambiguities are resolved on-the-fly by constraining the approximately known distances between the antennas that are rigidly mounted on the ship. Carrier phase thermal noise and multipath are minimized by mounting the antennas as far apart as possible. The four-antenna configuration provides redundancy and further improves accuracy. During the Matthew Motion Sensor Trials (MMST-93) conducted off the coast of Halifax, Nova Scotia, in June-July 1993, the GPS-derived attitude parameters were compared with those obtained with a Honeywell HG1050 ring laser gyro inertial navigation system (INS) which provides roll and pitch with an accuracy of 15 arcsecs and heading with an accuracy of 2 arcmins. To simulate rough weather conditions, sharp maneuvers were performed to induce roll angles in excess of 10°. No accuracy degradation nor any loss of GPS measurements occurred. The RMS agreement between GPS and INS derived attitude parameters is better than 2 arcmins in heading, 1 arcmin in pitch and 3 arcmins in roll. This level of accuracy demonstrates the capability of GPS for cost-effective shipborne attitude determination at an accuracy level of 0.05 相似文献
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State-dependent Riccati equation-based robust dive plane control of AUV with control constraints 总被引：1，自引：0，他引：1
The paper treats the question of suboptimal dive plane control of autonomous underwater vehicles (AUVs) using the state-dependent Riccati equation (SDRE) technique. The SDRE method provides an effective mean of designing nonlinear control systems for minimum as well as nonminimum phase AUV models. It is assumed that the hydrodynamic parameters of the nonlinear vehicle model are imprecisely known, and in order to obtain a practical design, a hard constraint on control fin deflection is imposed. The problem of depth control is treated as a robust nonlinear output (depth) regulation problem with constant disturbance and reference exogenous signals. As such an internal model of first-order fed by the tracking error is constructed. A quadratic performance index is chosen for optimization and the algebraic Riccati equation is solved to obtain a suboptimal control law for the model with unconstrained input. For the design of model with fin angle constraints, a slack variable is introduced to transform the constrained control input problem into an unconstrained problem, and a suboptimal control law is designed for the augmented system using a modified performance index. Using the center manifold theorem, it is shown that in the closed-loop system, the system trajectories are regulated to a manifold (called output zeroing manifold) on which the depth tracking error is zero and the equilibrium state is asymptotically stable. Simulation results are presented which show that effective depth control is accomplished in spite of the uncertainties in the system parameters and control fin deflection constraints. 相似文献
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Application of multiple hybrid underwater gliders (HUGs) is a promising method for large scale, long-term ocean survey. Attitude coordination has become a requisite for task execution of multi-HUG formation. In this paper, a multibody model is presented for attitude coordination among agents in the HUG formation. The HUG formation is regarded as a multi-rigid body system. The interaction between agents in the formation is described by artificial potential field (APF) approach. Attitude control torque is composed of a conservative torque generated by orientation potential field and a dissipative term related with angular velocity. Dynamic modeling of the multibody system is presented to analyze the dynamic process of the HUG formation. Numerical calculation is carried out to simulate attitude synchronization with two kinds of formation topologies. Results show that attitude synchronization can be fulfilled based on the multibody method described in this paper. It is also indicated that different topologies affect attitude control quality with respect to energy consumption and adjusting time. Low level topology should be adopted during formation control scheme design to achieve a better control effect. 相似文献
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This paper addresses the problem of simultaneous depth tracking and attitude control of an underwater towed vehicle. The system proposed uses a two-stage towing arrangement that includes a long primary cable, a gravitic depressor, and a secondary cable. The towfish motion induced by wave driven disturbances in both the vertical and horizontal planes is described using an empirical model of the depressor motion and a spring-damper model of the secondary cable. A nonlinear, Lyapunov-based, adaptive output feedback control law is designed and shown to regulate pitch, yaw, and depth tracking errors to zero. The controller is designed to operate in the presence of plant parameter uncertainty. When subjected to bounded external disturbances, the tracking errors converge to a neighbourhood of the origin that can be made arbitrarily small. In the implementation proposed, a nonlinear observer is used to estimate the linear velocities used by the controller thus dispensing with the need for costly sensor suites. The results obtained with computer simulations show that the controlled system exhibits good performance about different operating conditions when subjected to sea-wave driven disturbances and in the presence of sensor noise. The system holds promise for application in oceanographic missions that require depth tracking or bottom-following combined with precise vehicle attitude control. 相似文献
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A four‐antenna GPS attitude determination system was used to estimate roll, pitch, and heading parameters of a 52‐meter surveying vessel in an operational marine environment. The least squares algorithm for platform attitude estimation using multiple baseline vector observables is presented. An efficient on‐the‐fly carrier phase ambiguity searching method is derived, which utilizes the Cholesky decomposition method and the known baseline constraints between the GPS antennas to construct the potential ambiguity sets on the sphere. The accuracy of the estimated attitude parameters from the GPS multi‐antenna system was assessed with an independent inertial navigation system (INS). Results from sea trials show that the proposed GPS multi‐antenna system and processing algorithms delivered a satisfactory performance under various ship maneuvers. The accuracy of GPS estimated ship attitude parameters is better than 0.06 degrees at an output rate of 10 Hz. Such a performance demonstrates a new alternative means to provide accurate, reliable, and cost‐effective ship attitude information for hydrographic applications. 相似文献
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《Ocean Modelling》2011,40(3-4):351-361
In large-scale ocean flows diffusion mostly occurs along the density surfaces and its representation resorts to the Redi isopycnal diffusivity tensor containing off-diagonal terms. This study focuses on the Lagrangian/particle framework for simulating such diffusive processes. A two-dimensional idealised test case for purely isopycnal diffusion on non-flat isopycnal surfaces is considered. Implementation of the higher order strong Euler, Milstein and order 1.5 Taylor schemes on our idealised test case shows that the higher order strong schemes produce the better pathwise approximations. The effective spurious diapycnal diffusivity is measured for each Lagrangian scheme under consideration. The propensity of the particles to move away from the isopycnal surface on which they were released is also measured. This shows that for non-flat isopycnals the order of convergence of the Euler scheme is not sufficient to achieve the desired accuracy. However, the Milstein scheme seems to be a good choice to achieve in an efficient way a fairly accurate result. 相似文献
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A discrete time-delay control (DTDC) law for a general six degrees of freedom unsymmetric autonomous underwater vehicle (AUV) is presented. Hydrodynamic parameters like added mass coefficients and drag coefficients, which are generally uncertain, are not required by the controller. This control law cancels the uncertainties in the AUV dynamics by direct estimation of the uncertainties using time-delay estimation technique. The discrete-time version of the time-delay control does not require the derivative of the system state to be measured or estimated, which is required by the continuous-time version of the controller. This particularly provides an advantage over continuous-time controller in terms of computational effort or availability of sensors for measuring state derivatives, i.e., linear and angular accelerations. Implementation issues for practical realization of the controller are discussed. Experiments on a test-bed AUV were conducted in depth, pitch, and yaw degrees of freedom. Results show that the proposed control law performs well in the presence of uncertainties. 相似文献
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Pradeep R. Nambisan 《Ocean Engineering》2009,36(2):158-167
A multi-variable adaptive autopilot for the dive-plane control of submarines is designed. The vehicle is equipped with bow and stern hydroplanes for maneuvering. It is assumed that the system parameters are not known, and the disturbance force is acting on the vehicle. Based on a back-stepping design approach, an adaptive control law is derived for the trajectory control of the depth and the pitch angle. To prevent singularity in the control law, the SDU decomposition of the high-frequency gain matrix is used for the design. In the closed-loop system, asymptotic tracking of the reference depth and pitch angle trajectories is accomplished. Simulation results are presented which show that the submarine performs dive-plane maneuvers in spite of the uncertainties in the system parameters and disturbance forces. 相似文献
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We present a new type of model-free adaptive control (MFAC) method based on an adaptive forgetting factor for unmanned surface vehicle (USV) heading control under uncertain influence. Firstly, we analyze the compact form dynamic linearization based MFAC (CFDL-MFAC) method and its main problems with regard to USV heading control. Secondly, in order to address the problems of overshoot, oscillation, and slow convergence of the heading control with the MFAC method and considering the dynamics of the USV heading control subsystem, we introduce an adaptive forgetting factor into the CFDL-MFAC to arrive at the CFDL-MFAC with variable forgetting factor (CFDL-MFAC-VFF) method. Our simulation studies show that the CFDL-MFAC-VFF method yields low overshoot and low oscillations and is insensitive to changes in the system parameters and output error. Finally, our field experiments with the small USV “Dolphin-I” demonstrate the effectiveness and engineering practicability of our proposed method. 相似文献
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Zero-G Class Underwater Robots: Unrestricted Attitude Control Using Control Moment Gyros 总被引：1，自引：0，他引：1
The "Zero-G" is designated as a new class of underwater robot that is capable of unrestricted attitude control. A novel control scheme based on internal actuation using control moment gyros (CMGs) is developed to provide Zero-G class autonomous underwater vehicles (AUVs) with this unique freedom in control. This is implemented in the CMG-actuated Zero-G class internal kinematic underwater robot actuation (IKURA) system that was developed as part of this research. A series of experiments are performed to demonstrate the practical application of CMGs and verify the associated theoretical developments. The ability to actively stabilize the translational dynamics of the robot is assessed and unrestricted attitude control is demonstrated in an experiment that involves vertically pitched diving and surfacing in surge. Finally, potential applications for Zero-G class AUVs are discussed. 相似文献