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.
This paper proposes a finite-time robust flight controller, targeting for a reentry vehicle with blended aerodynamic surfaces and a reaction controlsystem(RCS). Firstly, a novel finite-time attitude controller is p...
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This paper proposes a finite-time robust flight controller, targeting for a reentry vehicle with blended aerodynamic surfaces and a reaction controlsystem(RCS). Firstly, a novel finite-time attitude controller is pointed out with the introduction of a nonsingular finite-time sliding mode manifold. The attitude tracking errors are mathematically proved to converge to zero within finite time which can be estimated. In order to improve the performance, a second-order finite-time sliding mode controller is further developed to effectively alleviate chattering without any deterioration of robustness and accuracy. Moreover, an optimization control allocation algorithm, using linear programming and a pulse-width pulse-frequency(PWPF) modulator, is designed to allocate torque commands for all the aerodynamic surface deflections and on–off switching-states of RCS *** are provided for the reentry vehicle considering uncertain parameters and external disturbances for practical purposes, and the results demonstrate the effectiveness and robustness of the attitude controlsystem.
Moving object detection is usually used in gray image, and the color image should be converted to gray images to achieve detection. However, the color object can’t be described by simple gray information completely. ...
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ISBN:
(纸本)9781479947249
Moving object detection is usually used in gray image, and the color image should be converted to gray images to achieve detection. However, the color object can’t be described by simple gray information completely. In order to achieve automatic color moving object detection, the method based on automatic color clustering is especially proposed. Because the difference between adjacent pixels in an image is very small, the initial cluster center can be moved in the maximum distance. The proposed method can reduce the number of iterations and quicken convergence speed, meanwhile determine the number of color cluster and the location of the color object automatically. The proposed algorithm is validated in the actual system, experimental results show that the proposed method can automatically achieve color clustering for color image, while detect color objects.
As an important research field of intelligent Transport system(ITS),Unmanned Ground Vehicles(UGV)can lessen traffic accidents and relieve traffic congestion by high intelligence,thereby improving the efficiency of the...
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ISBN:
(纸本)9789881563842
As an important research field of intelligent Transport system(ITS),Unmanned Ground Vehicles(UGV)can lessen traffic accidents and relieve traffic congestion by high intelligence,thereby improving the efficiency of the entire *** and more complex urban traffic environment forces UGV to perceive a lot of environmental information,and the Geographic Information system(GIS)has strong capabilities of storage and management for geographic ***,a new method for constructing GIS database is proposed in this paper,which combines the characteristics of urban traffic and needs for perceiving the environment of UGV,to assist UGV in moving in the urban traffic environment ***,Google Earth is used to create the city ***,an urban road network model is proposed and the GIS database of urban traffic environment is constructed based on the ***,the GIS database is used to achieve the least-time route based on improved Dijkstra ***,the GIS database can provide the attributive information of roads in the real vehicle experiment,which guides UGV to perceive the environment *** have shown that the proposed GIS database performs well in assisting UGV to move autonomously in the urban traffic environment.
Hydro-viscous speed clutch(HVC) is a central control element of the driver system. Because of nonlinearities and hysteresis of the clutch, the setting of control parameters has a significant impact on the performance ...
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Hydro-viscous speed clutch(HVC) is a central control element of the driver system. Because of nonlinearities and hysteresis of the clutch, the setting of control parameters has a significant impact on the performance of the speed controlsystem. This paper studies the HVC of a vehicle temperature controlsystem, and analyzes the parameters tuning method of a PID controller for the closed-loop controlsystem. By employing a two-storey optimized control framework, the resulting model from identification can be used to complete the control parameters auto-tuning. Simulation and experimental results have showed that this auto-tuning method can obtain a group of parameters in terms of a desired performance index, which guarantees the balance of dynamic characteristics, stability and anti-jamming in closed-loop system.
This paper studies a coordinated transportation problem of a group of unmanned ground vehicles(UGVs). These ground vehicles belong to two categories: master vehicles and slave vehicles. A two-step strategy is proposed...
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ISBN:
(纸本)9781467374439
This paper studies a coordinated transportation problem of a group of unmanned ground vehicles(UGVs). These ground vehicles belong to two categories: master vehicles and slave vehicles. A two-step strategy is proposed to solve this problem. First, let the master vehicles move along ideal trajectories. Then, let the slave vehicles move into the area surrounded by master vehicles and move together with them. By the two-step strategy, the coordinated transportation problem is divided into a tracking problem and a containment problem. A P In-type tracking protocol and a P In-type containment protocol(P and I stand for Proportion and Integration, respectively;Inimplies that the protocol includes high-order integral terms) are proposed to solve these two problems. It is proved that the coordinated transportation problem can be solved by two proposed protocols with proper parameters if for each follower there exists at least one leader which has a directed path to this follower. Finally, a simulation example is presented to demonstrate the effectiveness of the proposed algorithms.
This paper introduces the similarity evaluation on humanoid facial expression. For the purpose of understanding easily, firstly, the process of designing humanoid robot's facial expressions is explored in brief. T...
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ISBN:
(纸本)9781479970995
This paper introduces the similarity evaluation on humanoid facial expression. For the purpose of understanding easily, firstly, the process of designing humanoid robot's facial expressions is explored in brief. Then, a similarity function is proposed to evaluate the similarity of the robot facial motion compared with the human being quantitatively based on both the kinematics and dynamics factors, also including how to select the key value of parameter in similarity function. Finally, the effectiveness of the similarity function is confirmed by an experiment of facial expressions based on BHR-4 robot.
Considering two disadvantages in traditional gravity matching aided inertial navigation system,low matching accuracy and error accumulation,we propose an improved gravity matching algorithm and aided method for inerti...
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ISBN:
(纸本)9789881563842
Considering two disadvantages in traditional gravity matching aided inertial navigation system,low matching accuracy and error accumulation,we propose an improved gravity matching algorithm and aided method for inertial navigation *** of using the sequence sampling,the single point sampling is applied to improve the structure of proposed algorithm,enhancing the matching speed and *** the aided navigation system method,we use combination of Sage-Husa adaptive filter and strong-tracked Kalman filter to make further optimal estimation of the matching *** results show the effectiveness of the real-time ICCP algorithm and the combined filter *** to the traditional methods,proposed method provides higher matching and navigation accuracy.
Analysis and design of simulation scenario, design and application of scenario system are problems needed to be solved in the development and performance verification of simulation system. Consequently, a standardized...
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ISBN:
(纸本)9781479947249
Analysis and design of simulation scenario, design and application of scenario system are problems needed to be solved in the development and performance verification of simulation system. Consequently, a standardized development method for developing scenario based on a kind of combat information simulation system is proposed in this paper. Firstly, according to the requirements for generation of scenario which are decided by simulation system, the combining of military conceptual model and the entity oriented modeling method(EATI method) is used to build scenario structure model accurately and without distortion. Secondly, description of content and realizing form for scenario are constrained and standardized by extensible markup language(XML). Finally, a visualized and flexible scenario system model is built based on former theory analysis, which is independent of simulation system. This paper not only solves the problem existed in scenario and scenario system, but also implements rapid development of scenario, which provides important theory guiding meaning.
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