Papers by Keyword: Error Analysis

Abstract: The visual measurement technology is prerequisite to implement high accuracy pose measurement tasks for space manipulator. Firstly, a Newton Downhill-Least Square (ND-LS) algorithm is presented to optimize the object’s pose in this paper. Secondly, the pose measurement error caused by the focal ratio, the principal point, image coordinates and world coordinates is analyzed separately. Finally, the performance of suggested algorithm and the results of pose error analysis are evaluated respectively by re-projection error (RPE) and mean absolute of pose error (MAPE). Experimental results validate that the ND-LS algorithm is superior than Newton method or Least Square (LS) method in pose optimization. In general, solved by ND-LS algorithm, the RPE reduces nearly 3 times contrasted to initial value, and it also reduces to half of that obtained by both Newton method and LS method. On the other hand, the results of pose error analysis indicates that the error influenced by the principal point approximately equals to the one caused by image coordinates, about 2 and 15 times higher than what caused by both focal ratio and world coordinates, respectively, to orientation error with MAPE. Moreover, the relationships above are about 2 and 20 times separately as for the position error.

Abstract: The tool setting error model is put forward in this paper, according to the characteristics of the numerical control lathe tool setting error. On the basis of analyzing the influence factors of tool setting error, the influence of the tool setting error on the part shape error is discussed. Analysis shows that the shape error and size error is produced by the tool setting error, and the error will increase with the diameter size of tool setting error, the cutter diameter, amount of feed and other factors.

Abstract: Blades are important components of aviation-engine, with complex shape and high precision machining. The radius of curvature of the leading and trailing edges of the precision forging blades is small and the curvature changes fast. In this paper, the adaptive machining scheme about the leading/trailing edge of the precision forging blade is proposed. Firstly, the measurement model based on theoretical model of the blade is established. Secondly, according to the measurement model, the measurement path planning is proposed. Thirdly, measurement data processing and registration, then blade model reconstructed to generate the new NC code for machining.

Abstract: With the increasing complexity of the space mission, the ability of fast reconstruction of manipulator is more and more important. To solve the problem of space manipulator’s fast reconstruction, this paper designs a novel manipulator that contains mechatronics modular joints and a connecting mechanism. Compared to the traditional manipulator, the manipulator in this paper have the advantage of great convenience of assembling and replacement of the modular joint. In this paper, we analyze the relationship between tolerance ability and structural parameters and computed the tolerance ability after optimization of the connecting mechanism; Using the perturbation method, we conducted the simulation of analysis error. Results show that relationship between the end position error and the error of the modular joints is approximate linear, which providing a theory instruction for the design of manipulator.

Abstract: In this article the micro flow self-sensing actuator has carried on the theoretical analysis and experimental research. Using output micro-displacement generated by the first inverse piezoelectric effect to realize cell micro flow injection, using output voltage generated by secondary direct piezoelectric effect of piezoelectric ceramic to self-sensing the output displacement in the process of the micro flow injection. The experimental results show that the micro-displacement of micro-flow self-sensing actuator has nonlinear error, error is 5.03%. The error between measured micro-displacement and self-sensing micro-displacement is 63.13%. In this paper, the error causes analysis of micro-flow self-sensing actuator is from non-linearity and hysteresis, external factors, it lay the foundation for the further study of micro-flow self-sensing actuator.

Abstract: In order to describe the generalization ability, this paper discusses the error analysis of neural network with multiply neurons using rational spline weight functions. We use the cubic numerator polynomial and linear denominator polynomial as the rational splines for weight functions. We derive the error formula for approximation, the results can be used to algorithms for training neural networks.

Abstract: Based on research carried out for the most fuel-lunar soft landing trajectory optimization problem. First, by improving the function approximation method, the lunar soft landing trajectory optimization problem into a parameter optimization problem, and the optimization variables and state variables have a clear physical meaning. Then use the decimal ant colony algorithm adds local search strategy to study the optimization problem. Finally, the optimization algorithm to optimize term direction angle simulation and error analysis.

Abstract: With the development of science and technology , the position of the strength measurement^[1] in national economic development is more and more important, In recent years, along with the computer technology, electronic technology and the development of numerical control technology, force standard machine also obtained the rapid development^[2-6],dead weight force standard machine strength measuring accuracy is the highest power source device by far, in the process of weight loading, considering the axial load affect the performance of the whole machine and in order to guarantee the machine safe and reliable, it is necessary to eccentric loading conditions for mechanical properties analysis.

Abstract: In order to satisfy the orientation measuring requirements of rigid-body such as work piece, cutting tool in industry, the paper presents a binocular vision detection technique based on spatial position information of markers to extract rigid-body pose information and analyzes the pose accuracy of rigid-body using the principal component analysis (PCA) when spatial position error of markers exist. The simulation experiment demonstrates the maximum angle error of orientation is about 0.59 degree when the position error of markers satisfy the Gaussian distribution with the mean is zero and the standard deviation is 0~3mm. The experimental results verify this method can robustly solve the orientation of rigid body using the position information of markers with position errors, and it provides a theoretical and experimental basis for orientation measurement of rigid body.

Abstract: Based on the chirp signal radar using DDS technology, the waveform of the wideband chirp signal source is analyzed. By analyzing the system error model, the method that selecting the chirp steps in accordance with the digits of DDS phase truncation is proposed. It reduces the system errors caused by the phase truncation.