Path planning is a core problem of the mobile robot navigation technology. However, few path plan methods that have been proposed consider the path smoothness and the robot attitude in the path. In this paper, a novel...
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Path planning is a core problem of the mobile robot navigation technology. However, few path plan methods that have been proposed consider the path smoothness and the robot attitude in the path. In this paper, a novel path planning method is proposed which considers three optimizing targets, including the path length, the path smoothness and the distance between the path and the obstacles. Firstly, a localization method which the path planning method relies on is explained. Secondly, a path planning model considering the path smoothness and the robot posture is discussed in detail. Thirdly, a solution based on particle swarm optimization (PSO) algorithm is discussed. Fourthly, simulation results are shown and analyzed. At last, conclusion and future work are provided.
In this paper,we proposed a hybrid method in extracting the attitude parameters of unmanned aerial vehicle(UAV), which is based on computer vision and improved artificial bee colony(ABC) *** is used as a characteristi...
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ISBN:
(纸本)9781479900305
In this paper,we proposed a hybrid method in extracting the attitude parameters of unmanned aerial vehicle(UAV), which is based on computer vision and improved artificial bee colony(ABC) *** is used as a characteristic line, whose two parameters,Φandσare utilized to obtain UAV's parameters:roll angleΨand pitch angleθ.Defogging Algorithm is used to make the original pictures clearer and gain the transmission image for horizon *** UAV could obtain the horizon through improved ABC *** also analyzed the relationship between line parameters and UAV parameters and calculated the UAV *** results verified the feasibility and effectiveness of our presented approach.
In this paper, we present a systematic control design for strict-feedback nonlinear systems with output constraints using tangent Barrier Lyapunov Functions (BLFs-Tan). Both symmetric and asymmetric BLF-Tan based back...
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In this paper, we present a systematic control design for strict-feedback nonlinear systems with output constraints using tangent Barrier Lyapunov Functions (BLFs-Tan). Both symmetric and asymmetric BLF-Tan based backstepping control design methods are developed. It is proved that with the proposed approach and Lyapunov synthesis, the output constraints are not violated, all signals in the closed-loop systems are bounded, and asymptotical tracking is achieved. Through the simulation, we also perform a comparison study between BLF-Tan and the logarithmic BLF (BLF-Log) to illustrate the difference in control performance, and show that the performance of asymmetric BLF-Tan based controller depends on the position of initial tracking error with respect to the transformed constraint boundary.
A ground control system (GCS) for unmanned aerial vehicles (UAV) is developed in this paper. Different tasks, which include real time communication between GCS and UAVs, data processing and storing, localization, path...
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A ground control system (GCS) for unmanned aerial vehicles (UAV) is developed in this paper. Different tasks, which include real time communication between GCS and UAVs, data processing and storing, localization, path planning and so on, can be accomplished in the proposed GCS. To address the issue of path planning problem for UAVs, a new path planning algorithm based on potential function is proposed to drive the UAV to its destination in this paper. Time-varying gain adjusting method is used to enable the UAV obstacle avoidance ability under the constraints for the translation velocity. Lyapunov based analysis is used to prove the stability of the proposed algorithm. Numerical simulation results are included to demonstrate the performance of the proposed path planning design.
Deployable structures, as an important kind of structure, have been widely used in a variety of satellite antennas and space *** research of deployable structures usually faces a series of theoretical and technical ch...
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Deployable structures, as an important kind of structure, have been widely used in a variety of satellite antennas and space *** research of deployable structures usually faces a series of theoretical and technical challenges because the size and mass are not only the limitations of deployable structure but also the key issues in the design ***, the appearance of bionic provides a new concept to develop the deployable *** by the eclosion and development
This paper investigates the optimal feet forces distribution and control of quadruped robots under external disturbance forces. First, we formulate a constrained dynamic model of quadruped robots and derive a reduced ...
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This paper investigates the optimal feet forces distribution and control of quadruped robots under external disturbance forces. First, we formulate a constrained dynamic model of quadruped robots and derive a reduced order dynamical model of motion/force. Consider an external wrench on quadruped robots, the distribution of required forces and moments on the supporting legs of a quadruped robot is handled as a tip-point force distribution and used to equilibrate the external wrench. Then, a gradient neural network is adopted to minimize the optimized objective function with linear equality and inequality constraints, and hybrid motion/force control based on adaptive neural network is used to compensate for the external perturbation in the environment and approximate feedforward force and impedance of the leg joints on line. The verification of the proposed control is conducted using the extensive simulations.
US (Ultrasonic) motors have potential applications as MR-compatible actuators for MRI-guided surgical robots. MR compatibility test of US motors (Shinsei USR 30 and USR 60) were performed in 3T MRI scanner under basel...
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US (Ultrasonic) motors have potential applications as MR-compatible actuators for MRI-guided surgical robots. MR compatibility test of US motors (Shinsei USR 30 and USR 60) were performed in 3T MRI scanner under baseline, power-off, power-on, and moving configurations with mounting orientations parallel and perpendicular to the longitudinal bore axis. Normalized SNR was used to calculate the MR compatibility of US motors. The results show that the safe distances for USR 30 and USR 60 from the isocenter are 15cm and 20cm, respectively. Moving configuration decreased the normalized SNR by 15%-25%. In the same mounting orientation, three imaging sequences performed differently in terms of quality of MR images. To conclude, the Shinsei USR 30 and USR 60 are suitable for providing actuation of MRI-guided surgical robot during real-time imaging, and the MR compatibility could be improved by selecting suitable safe distance and mounting orientation.
Delamination is a major problem in drilling of fiber-reinforced composite materials. Thrust force is an important factor leading to propagation of delamination during drilling process. One of effective methods to redu...
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Delamination is a major problem in drilling of fiber-reinforced composite materials. Thrust force is an important factor leading to propagation of delamination during drilling process. One of effective methods to reduce machining forces is application of ultrasonic vibrations. In this study ultrasonic assisted drilling is applied to reduce thrust force in drilling of GFRP laminates. In order to conduct experiments a setup is designed and fabricated to apply both vibrations and rotation to drill bits. Using Taguchi method, a set of experiments is conducted with feed rate, spindle speed, and ultrasonic vibration amplitude as control factors. The results show that applying ultrasonic vibration reduces the thrust force and therefore the drilling induced delamination dramatically.
A method for road boundary detection and tracking using laser ladar with respect to a vehicle' s local coordinates is proposed. It can be applied to different types of road conditions, such as roads with or without c...
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A method for road boundary detection and tracking using laser ladar with respect to a vehicle' s local coordinates is proposed. It can be applied to different types of road conditions, such as roads with or without curbs, having relatively rough road surface and with obstacles on road surface. In the method, some line segments are extracted after a series of preprocessing on range data. The extracted line segments are combined and further selected. They are then united to match the road models and generate the road boundary points which are tracked by Kalman filter. Then the obtained road boundary points are transformed to build a precise vector map by least squares fitting algorithm. These fitted line segments represent road boundary vectors. The vector map is precise enough to provide ample road information such as the orientation of road, the road width and the passable road region. Finally, extensive experiments conducted in urban and semi-urban environment demonstrate the robustness, effectiveness and viability of the proposed method.
Due to the intense vibration durirLg launching and rigorous orbital temperature environment, the kinematic parameters of space robot may be largely deviated from their nominal parameters. The disparity will cause the ...
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Due to the intense vibration durirLg launching and rigorous orbital temperature environment, the kinematic parameters of space robot may be largely deviated from their nominal parameters. The disparity will cause the real pose (including position and orientation) of the end effector not to match the desired one, and further hinder the space robot from performing the scheduled mission. To improve pose accuracy of space robot, a new self-calibration method using the distance measurement provided by a laser-ranger fixed on the end-effector is proposed. A distance-measurement model of the space robot is built according to the distance from the starting point of the laser beam to the intersection point at the declining plane. Based on the model, the cost function about the pose error is derived. The kinematic calibration is transferred to a non-linear system optimization problem, which is solved by the improved differential evolution (DE) algoritlun. A six-degree of freedom (6-DOF) robot is used as a practical simulation example, and the simulation results show: 1) A significant improvement of pose accuracy of space robot can be obtained by distance measurement only; 2) Search efficiency is increased by improved DE; 3) More calibration configurations may make calibration results better.
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