For a ground target tracking system using an unmanned helicopter, an on-board pan-tilt controller is proposed to adjust the attitude of the camera, so that to keep the target staying at the center of the image plane w...
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For a ground target tracking system using an unmanned helicopter, an on-board pan-tilt controller is proposed to adjust the attitude of the camera, so that to keep the target staying at the center of the image plane when the target is in sight. When the target is temporarily out of view due to various reasons, the designed controller will make the camera quickly re-capture the target by estimating its state and then regulating the orientation of the camera correspondingly. Specifically, a novel state transformation is firstly introduced to make the error system independent of the target image. Subsequently, a nonlinear pan-tilt controller is designed for the transformed error system. Lyapunov techniques are then employed to prove that the target tracking error in the image plane is driven to zero exponentially fast. To facilitate the implementation of the constructed controller, a visual estimator is also utilized to obtain the state information of the target even if it is occasionally out of the view of the camera by introducing an effective nonlinear filter. Simulation results are provided to validate the performance of the presented control system.
In order to quickly operate large quantities of cells and obtain optimized operation sequence, it is ideal to get location information of overall cells to be operated. Therefore this paper collects low-resolution micr...
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In order to quickly operate large quantities of cells and obtain optimized operation sequence, it is ideal to get location information of overall cells to be operated. Therefore this paper collects low-resolution microscopic images in which we can observe a large sum of cells. To obtain their accurate locations, this paper puts forward Improved Circle Similarity Algorithm for solving the problem of positioning large quantities of cells, which improves the Circle Similarity Algorithm. The method has been applied into experimental environment and its results in positioning accuracy, positioning precision and image rotation invariance aspects meet the need of application in the micro-manipulator systems. The method successfully solves the problem of positioning large quantities of cells in microscopic images.
In this paper, we are concerned with the registration of two 3D data sets with large-scale stretches and noises. First, by incorporating a scale factor into the standard iterative closest point (ICP) algorithm, we for...
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In order to realize the miniaturized nano-positioning stage, a novel 2-DOF Single Crystal Silicon (SCS) nano-positioning micro X-Y stage with the function of displacement detection is successfully developed by using s...
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In order to realize the miniaturized nano-positioning stage, a novel 2-DOF Single Crystal Silicon (SCS) nano-positioning micro X-Y stage with the function of displacement detection is successfully developed by using silicon bulk-micromachining;the X-Y stage is drived by an electrostatics comb actuator. The theories of electromechanical coupling and energy conservation are used to analyze electrostatic actuated mechanism, X-Y stage static characteristic and X-Ystage dynamic characteristic. Some failure modes of X-Y stage are also presented and the electromechanical side instability and the stable travel range of comb-drive actuators are investigated. The stable travel range depends on the finger gap spacing, the initial finger overlap and the spring stiffness ratio of the compliant suspension. Additionally, by taking into account the effect of the air damping on the X-Ystage dynamic characteristic, the maximum velocity, stable travel range and critical driving voltage are given to an experiment on closed-loop control. The experimental results indicate that the analyzed characteristics are useful in the design and control of the micro X-Ystage. Under 30 V driving voltage, the single-axis displacement output is 10 μm, and the closed-loop step response is only 2.5 ms.
A modified APF (artificial potential field) based method is proposed for mobile robot path planning. To address the local minima problem in the classical APF, a method composed of robot regression and potential field ...
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A modified APF (artificial potential field) based method is proposed for mobile robot path planning. To address the local minima problem in the classical APF, a method composed of robot regression and potential field filling is proposed. Futhermore, by adjusting potential field in the environment dynamically, the collision problem is also well settled. Simulation experiments, in which eight sonar transmitters are supposed to be used for environment measurement, are carried out to verify the performance of the path planning method proposed in the paper. The simulation results show that the modified APF has a better performance than the classical APF in an unknown environment.
A global localization method is proposed for mobile robot. This algorithm is based on Bayesian filtering theory and Markov process. A set of particles is utilized to describe the distribution of robot localization. Th...
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A global localization method is proposed for mobile robot. This algorithm is based on Bayesian filtering theory and Markov process. A set of particles is utilized to describe the distribution of robot localization. The set is updated according to the map information and sonar data step by step. In this way the particles converge to the true localization rapidly. In this paper, the map is recorded as set of sections of line, which takes little storage space and benefit calculation. Simulation results show the effectiveness of this algorithm.
This paper firstly described the technical performances required for the robot that could be used in the micro-surgery. Then it made a simple introduction to the prototype of Robot Assistant Micro-Surgery (RAMS) syste...
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This paper firstly described the technical performances required for the robot that could be used in the micro-surgery. Then it made a simple introduction to the prototype of robot assistant micro-surgery (RAMS) syste...
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This paper firstly described the technical performances required for the robot that could be used in the micro-surgery. Then it made a simple introduction to the prototype of robot assistant micro-surgery (RAMS) system. After an analysis to the typical operations of micro-surgeries, we developed a simple and practical motion planning algorithm based on S-curve. Both kinematical and dynamical simulations were carried out as verifications to its validity and efficiency. At last, the article presented the results of micro-surgical experiment with animal
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