By combination of parallelogram link and gear, a new type of exoskeleton mechanism is developed. As placed on the back of extra vehicular activity (EVA) glove in an external way, this mechanism is able to drive the EV...
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By combination of parallelogram link and gear, a new type of exoskeleton mechanism is developed. As placed on the back of extra vehicular activity (EVA) glove in an external way, this mechanism is able to drive the EVA glove finger to extent or flex like human finger grasp *** force sensor located at the tip of exoskeleton mechanism measures the EVA glove damping force during flexion or extension. The force reaches even to 10 N and the hysteresis of the force approaches to 31%.To predict the force which corresponds to an angular displacement of EVA glove and simulate the human factors performance metrics of extra vehicular activity, an unified Preisach numerical calculating strategy is presented by recording the number of vertices of the interface line in discrete Preisach plane and getting a series of first order reversal curves. A distance-weighted interpolation is chosen to evaluate at the points belonging to the Preisach plane except the discrete grid points. The proposed method is validated by the experiments.
In order to searching the best threshold of Otsu rule rapidly, a modified strategy to the inertia weight in Particle Swarm Optimization (PSO) is introduced. The strategy correlates the inertia weight in PSO with the g...
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In order to searching the best threshold of Otsu rule rapidly, a modified strategy to the inertia weight in Particle Swarm Optimization (PSO) is introduced. The strategy correlates the inertia weight in PSO with the globally best position and the individual best position in particle swarm and modifies the inertial weight by the distance between the best individual position and the globally best position. With the reduction of the distance between the globally best position and the individual best position, the inertia weight of the individual particle will be reduced, vice versa. The experimental results indicate that this algorithm decreases computational work and improves average convergence rate by 21.0726% as compared with that of traditional methods. It can speed up on-line image segmentation using this method.
In this paper, an improved algorithm to measure China's EMU spacesuit joint damping parameters for the old passive robot system is presented. The measuring principle is based on robot kinematics and dynamics. Firs...
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In this paper, an improved algorithm to measure China's EMU spacesuit joint damping parameters for the old passive robot system is presented. The measuring principle is based on robot kinematics and dynamics. Firstly, a kinematic model of the passive robot and the EMU spacesuit's arm is built according to the special mechanical structure. Secondly, improved methods of solving the inverse kinematics of the EMU spacesuit arm including flexible joints are proposed. And finally, a new algorithm that eliminates the gravity effect is implemented to calculate the damping torques of the EMU spacesuit joints. Experimental results and verification on SGI workstation proved the correctness and effectiveness of the proposed measuring method.
In order to analyze the performance of lunar rover, drawbar pull and motion resistance are analyzed in this paper based on terramechanics. The relationships between configuration parameters (like wheel width, wheel ba...
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ISBN:
(纸本)9781424424948
In order to analyze the performance of lunar rover, drawbar pull and motion resistance are analyzed in this paper based on terramechanics. The relationships between configuration parameters (like wheel width, wheel bases et al.) and mobility performance parameters are obtained from the analysis. Meanwhile, the sensitive factors of the motion resistance are found. Then main performance evaluation metrics and indexes of mobility performance are presented, based on which performance comparison of LER-1 and ALR (a new configuration lunar rover) locomotion systems is performed. The method of evaluating mobility performance of lunar rover by simulation is introduced. The analysis results indicate that the new locomotion system configuration ALR has good mobility performance. The study results can apply to the design of planetary exploration rovers for reference.
After analyzing the reasons related to the pixel nonuniformity in details, an algorithm based on least square method is presented to correct the pixel nonuniformity of a CCD. The grey level datum sets of each pixel ar...
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After analyzing the reasons related to the pixel nonuniformity in details, an algorithm based on least square method is presented to correct the pixel nonuniformity of a CCD. The grey level datum sets of each pixel are acquired on the cases of different irradiances, then a least square method is used to estimate the relation between irradiance and desired grey level data. The correct parameters of each pixel are computed, and the correct matrix is established. Finally, the pixel response uniformity is achieved by using the matrix to correct the grey level data of each pixel. The maximum deviation is 76.5 before correcting, while correcting by the proposed method, the maximum deviation is only 0.00108. The experimental results indicate that the method is effective to correct CCD nonuniformity.
A control strategy that combines input shaping with PD feedback control is presented in this paper. Input shaping was used to cancel the swing of the bucket, and feedback was used to detect and eliminate the position ...
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ISBN:
(纸本)9781424425020
A control strategy that combines input shaping with PD feedback control is presented in this paper. Input shaping was used to cancel the swing of the bucket, and feedback was used to detect and eliminate the position error of the trolley. Simulation of the bucket dynamics was carried on to evaluate the performance of the controller.
An integrated micro XY-stage with a 2 × 2 mm2 movable table is designed and fabricated for application in nanometer-scale operation and nanometric positioning precision. The device integrates the functions of bot...
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This paper presents the design, fabrication, and application of an electrostatically driven microgripper integrated piezoresistive force sensor. The microgripper is designed to manipulate two microobjects at the same ...
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This paper presents the design, fabrication, and application of an electrostatically driven microgripper integrated piezoresistive force sensor. The microgripper is designed to manipulate two microobjects at the same time with force sensing ability. Surface and bulk micromachining technology is employed to fabricate the microgripper from single crystal silicon wafer. The end effector of the gripper is a four arms structure, two fixed cantilever beams integrated with piezoresistive sensor are designed to sensing the gripping force, and an electrostatically driven microactuator is designed to provide the force to operate the other two movable arms. In this way, the four fingers structure enables the gripper to grasp two samples with different sizes at the same time. Experimental results show that it can successfully provide force sensing and play a main role in preventing damage of microparts in micromanipulation and microassembly tasks.
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