This paper is concerned with adaptive filter and its application in SINS/GPS/DVS integrated navigation. A novel adaptive filter, namely, SH–STF, is presented by combining the Sage–Husa(SH) adaptive filter with the s...
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ISBN:
(纸本)9781467374439
This paper is concerned with adaptive filter and its application in SINS/GPS/DVS integrated navigation. A novel adaptive filter, namely, SH–STF, is presented by combining the Sage–Husa(SH) adaptive filter with the strong tracking filter(STF). For multirate sampling dynamic system and in consideration of observations randomly missing, SH–STF is applied to data fusion and SINS/GPS/DVS integrated navigation. Simulation results show the feasibility and effectiveness of the presented algorithm.
The problem of generating optimal paths for curvature-constrained unmanned aerial vehicles (UAVs) performing surveillance of multiple ground targets is addressed in this paper. UAVs are modeled as Dubins vehicles so...
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The problem of generating optimal paths for curvature-constrained unmanned aerial vehicles (UAVs) performing surveillance of multiple ground targets is addressed in this paper. UAVs are modeled as Dubins vehicles so that the constraints of UAVs' minimal turning radius can be taken into account. In view of the effective surveillance range of the sensors equipped on UAVs, the problem is formulated as a Dubins traveling salesman problem with neighborhood (DTSPN). Considering its prohibitively high computational complexity, the Dubins paths in the sense of terminal heading relaxation are introduced to simplify the calculation of the Dubins distance, and a boundary-based encoding scheme is proposed to determine the visiting point of every target neighborhood. Then, an evolutionary algorithm is used to derive the optimal Dubins tour. To further enhance the quality of the solutions, a local search strategy based on approximate gradient is employed to improve the visiting points of target neighborhoods. Finally, by a minor modification to the individual encoding, the algorithm is easily extended to deal with other two more sophisticated DTSPN variants (multi-UAV scenario and multiple groups of targets scenario). The performance of the algorithm is demonstrated through comparative experiments with other two state-of-the-art DTSPN algorithms identified in literature. Numerical simulations exhibit that the algorithm proposed in this paper can find high-quality solutions to the DTSPN with lower computational cost and produce significantly improved performance over the other algorithms.
The extended state observer, a crucial part of the active disturbance rejection control, was first proposed in 1995 by Jingqing Han. The discrete-time form of the extended state observer has been extensively used in m...
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ISBN:
(纸本)9781467374439
The extended state observer, a crucial part of the active disturbance rejection control, was first proposed in 1995 by Jingqing Han. The discrete-time form of the extended state observer has been extensively used in many practical applications in engineering such as quad-rotor robot control and non-circular machining control;the convergence property of the discrete-time n-dimensional extended state observer, however, remains unexplored and is investigated in this work. The main idea is to construct the error equations of the discrete-time extended state observer for an n-dimensional single-input-single-output nonlinear system with uncertainty, and to prove the convergence of the extended state observer through induction.
A near minimum time feedback control law is proposed for the agile satellite attitude control system. The real time controller is formed by specially designed cascaded subunits. Based on this, the rapid attitude maneu...
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ISBN:
(纸本)9781467374439
A near minimum time feedback control law is proposed for the agile satellite attitude control system. The real time controller is formed by specially designed cascaded subunits. Based on this, the rapid attitude maneuvering can be applied in tasks including the move to move case. The near optimal property of that is guaranteed by the rapid dynamic response with a modified bang-bang control logic while simultaneously ensuring non-saturation properties on 3-Axis. The near optimal method is utilized for an online attitude planning, and the generated attitude maneuver path in real time is tracked by a nonlinear back-stepping controller with its improved dynamic performance and by which the united closed loop control is *** simulations are conducted to verify the effectiveness of the proposed control strategy.
For the local path planning problem of autonomous vehicle in a complicated environment, a method combining cubic hermite spline curves with the kinematic model of autonomous vehicle is developed. And a novel algorithm...
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For the local path planning problem of autonomous vehicle in a complicated environment, a method combining cubic hermite spline curves with the kinematic model of autonomous vehicle is developed. And a novel algorithm for obstacle avoidance, called navigation circle, is proposed to take the road structure into account, which is a practical method for real-time path planning. In the new method, one of the trajectory generated by cubic hermite spline curves or navigation circle is optimized through the kinematic model of autonomous vehicle to get the kinematically feasible trajectory. The optimization is actually a numerical forward propagation and is easy to implement. The simulation experiment is conducted on the Robot Operating System (ROS) platform, which is based on replaying the data of the real world obtained from sensors or other modules on autonomous vehicle. Satisfactory simulation results verify the validity and the efficiency of the proposed method as well as the planner's capability to navigate in a realistic scenario.
The terminal guidance problem for an unpowered lifting reentry vehicle against a sta- tionary target is considered. In addition to attacking the target with high accuracy, the vehicle is also expected to achieve a des...
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The terminal guidance problem for an unpowered lifting reentry vehicle against a sta- tionary target is considered. In addition to attacking the target with high accuracy, the vehicle is also expected to achieve a desired impact angle. In this paper, a sliding mode control (SMC)-based guidance law is developed to satisfy the terminal angle constraint. Firstly, a specific sliding mode function is designed, and the terminal requirements can be achieved by enforcing both the sliding mode function and its derivative to zero at the end of the flight. Then, a backstepping approach is used to ensure the finite-time reaching phase of the sliding mode and the analytic expression of the control effort can be obtained. The trajectories generated by this method only depend on the initial and terminal conditions of the terminal phase and the instantaneous states of the vehicle. In order to test the performance of the proposed guidance law in practical application, numerical simulations are carried out by taking all the aerodynamic parameters into consideration. The effec- tiveness of the proposed guidance law is verified by the simulation results in various scenarios.
The state estimation of general nonlinear systems is investigated through a parameter-dependent approach. This paper adopts the polytopic approximation for the nonlinear systems, which facilitates the application of a...
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ISBN:
(纸本)9781467374439
The state estimation of general nonlinear systems is investigated through a parameter-dependent approach. This paper adopts the polytopic approximation for the nonlinear systems, which facilitates the application of analytical approaches for resultant convex-bounded linear systems into the given nonlinear systems. The design of a high performance H2 state estimator is firstly determined by solving a convex optimization problem constrained by relaxed linear matrix inequalities(LMIs). The tensor product(TP) model transformation is then adopted to obtain the polytopic linearization. Specifically, A new process is presented to correct the result of the TP model transformation such that a necessary condition to solve the state estimation problem is assured. Finally, a numerical simulation is performed to illustrate the design process and verify the performance.
A novel high-order sliding mode control strategy is proposed for the attitude control problem of reentry vehicles in the presence of parametric uncertainties and external disturbances, which results in the robust and ...
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A novel high-order sliding mode control strategy is proposed for the attitude control problem of reentry vehicles in the presence of parametric uncertainties and external disturbances, which results in the robust and accurate tracking of the aerodynamic angle commands with the finite time convergence. The proposed control strategy is developed on the basis of integral sliding mode philosophy, which combines conventional sliding mode control and a linear quadratic regulator over a finite time interval with a free-final-state and allows the finite-time establishment of a high-order sliding mode. Firstly, a second-order sliding mode attitude controller is designed in the proposed high-order siding mode control framework. Then, to address the control chattering problem, a virtual control is introduced in the control design and hence a third-order sliding mode attitude controller is developed, leading to the chattering reduction as well as the control accuracy improvement. Finally, simulation examples are given to illustrate the effectiveness of the theoretical results.
The optimal path planning for fixed-wing unmanned aerial vehicles(UAVs) in multi-target surveillance tasks(MTST) in the presence of wind is *** take into account the minimal turning radius of UAVs,the Dubins model is ...
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The optimal path planning for fixed-wing unmanned aerial vehicles(UAVs) in multi-target surveillance tasks(MTST) in the presence of wind is *** take into account the minimal turning radius of UAVs,the Dubins model is used to approximate the dynamics of *** on the assumption,the path planning problem of UAVs in MTST can be formulated as a Dubins traveling salesman problem(DTSP).By considering its prohibitively high computational cost,the Dubins paths under terminal heading relaxation are introduced,which leads to significant reduction of the optimization scale and difficulty of the whole ***,in view of the impact of wind on UAVs' paths,the notion of virtual target is *** application of the idea successfully converts the Dubins path planning problem from an initial configuration to a target in wind into a problem of finding the minimal root of a transcendental ***,the Dubins tour is derived by using differential evolution(DE) algorithm which employs random-key encoding technique to optimize the visiting sequence of ***,the effectiveness and efficiency of the proposed algorithm are demonstrated through computational *** results exhibit that the proposed algorithm can produce high quality solutions to the problem.
Aiming to improve the control precision of pump-HA(high pressure automatic variables) motor speed controlsystems, the characteristic of HA motor displacement control mechanism is analyzed, and the mathematical model ...
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ISBN:
(纸本)9781467371902
Aiming to improve the control precision of pump-HA(high pressure automatic variables) motor speed controlsystems, the characteristic of HA motor displacement control mechanism is analyzed, and the mathematical model of pump-HA motor system is established. Taking the nonlinear character of the system, the system is approximated to a few of first order plus time delay processes, according to the working conditions. Parameters of the system models under different working conditions are identified by step response identification, PID parameters are tuned by a parameter tuning algorithm. A UKF state estimator is designed to estimate the load torque on the basis of the state space model established, then PID parameters are switched according to the desired speed and load torque. The research results indicate that switched PID control can ensure the system always has a good dynamic performance under different conditions and improve the control precision, making the system deal with various complex working conditions.
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