Liang Hou

The Integrated Testing System for Performance Parameters of the Hydraulic Excavator

This paper designed and developed an integrated testing system for performance parameters of the Hydraulic excavator. Combined with sensing technology, computer technology and virtual instrument technology this system can detect six key parameters of the excavator including motor speed, hydraulic system pressure, attachment action time, swing speed, walking speed, current characteristics, so as to evaluate the performance of the excavator. The testing system takes full consideration of the interaction between the tester and driver, meanwhile, can automatically detect all parameters by using the parallel test method in order to make sure the whole test completed in one hour. As the testing system is designed base on the idea of modularization, it can add new modules to meet the functional requirements alone with the development of research in the future. This testing system can not only improve the test efficiency, but also be used as analysis tools for the research and optimization of performance parameters of excavators.

Simulation of ride comfort of tracked vehicle based on road random excitation

By simplifying the triangular tracked engineer vehicle into dynamic model of half-tracked vehicle with five freedom degrees which includes four vertical jumps and one rotation, a corresponding dynamic differential equation is set up to each degree of freedom. A method of road roughness simulation, based on the time series of White Noise, is also represented and then verified. The simulation analysis of the tracked vehicle ride comfort is built on MATLAB/SIMULINK, based on the incentive signal of an imitated road. The simulation results show that the method that White Noise generated road roughness is applicable and prove efficient in the ride comfort research of the triangular tracked engineer vehicle. Thus a theoretical foundation is established for the optimization for ride comfort of the triangular tracked engineer vehicle.

Using wavelet denoising in automatic online efficiency estimation of a hydraulic excavator

A hydraulic excavator has a number of devices attached, the operating speeds of which are important performance indicators for performance evaluation and end-of-line inspection. This paper proposes an online and low-cost detection method to estimate the operating speed based on the peak detection of the main pump outlet pressure. A pressure sensor is installed on the main pump discharge point of a hydraulic excavator to collect real-time pressure data during operation. Then the wavelet method is deployed to denoise the obtained pressure data so that two special peak points are captured as start and end points for accurately estimating the operating time and speed of excavator devices. The proposed system is used for end-of-line inspection and performance evaluation of hydraulic excavators. Experimental results from 510 groups of data show that the proposed method can achieve a high success rate of 95.1%, and a high detection efficiency that is 60% faster than manual measurement.

Evolution Balancing of the Small-Sized Wheel Loader Assembly Line

Assembly line balancing not only directly determines production efficiency but also influences precision and quality of key assemblies or even the overall performance of final products. Driven by market demand and development of science and technology, product family must evolve constantly, which necessitates frequent adjustment and rebalancing of product family assembly line (PFAL). In order to maintain production efficiency, improve assembly quality and precision, and reduce costs for adjustment, the evolution balancing problem of PFAL for small-sized wheel loader is solved in this paper. Firstly, the evolution balancing model of PFAL is put forward. Then, with minimizing the number of workstations, the in-station and between-station load indexes and adjustment costs, and maximizing relevancy between activities as optimization objectives, meanwhile regarding product platform planning, modularity design and the critical chain technology in concurrent engineering as constraint conditions, the evolution balancing problem of PFAL is optimized using improved genetic algorithm (IGA). Finally, the whole analysis procedure is demonstrated by the small-sized wheel loader PFAL case study and the effectiveness of the proposed method is verified.

Evaluation and analysis in product evolution design

aiming at the difficulty of dynamic evaluation and realizing innovation in Product Family Evolution (PFE), an evaluation method of the product family for mass customization is presented by analyzing the influences of customer needs, enterprise resources and product data in the implementation process of Product Family (PF). From the perspective of time and space, the dynamic and static relative of PFE is summarized. In order to judge the situation of current product family and achieve the evolution innovation of product family, a comparative evaluation model for the product family based on Grey Conjunction Degree is established. Finally, the effectiveness and feasibility of the method were proved by evaluation and analysis of Small Wheel Loaders (SWLs).

Commonality Index of Outsourced Function Module Based on Generalized Dice Coefficient

Commonality analysis is the starting point of product family redesign, providing guidance for enterprises to improve commonality, reduce product cost and manufacturing complexity. Firstly, the component-based commonality indices introduced so far are analyzed and the deficiency in respect to commonality evaluation of outsourced function module is indicated. Then, the generalized performance matrix of outsourced function module is established and the commonality index based on generalized Dice coefficient is introduced. Finally, the calculation process is demonstrated by a case study of engine modules. The proposed index is of certain significance to reduce the types of outsourced module instances, save procurement and management cost and reduce the complexity of manufacturing systems.

Research on tooth profile design of spur gears based on line of action

This paper aims to propose a design method for tooth profiles of spur gears based on given line of action. A simplified derivation of the mathematical model of tooth profiles is introduced according to the meshing theory. Tooth profiles of spur gears, using a parabola as line of action, is established. The result shows that it will be better to control the performances of a gear set by specifying the shape of the line of action rather than specifying tooth profiles of mating gear.

Research on the evolution & innovation for modular product family

Focusing on the shortage of dynamic evolutionary mechanism and systematic innovation methods of current product family,an innovative and evolutional method at the technical level of modular product family is put forward.The current technical condition of the modular product family is analyzed by constructing requirement-function-technology(R-F-T) mapping model of product family,and the importance of future technology of modular product family is predicted by GM(1,1) model.The multiple conflicts of product family is identified and resolved using PFN technology in the OTSM –TRIZ process,through the analysis of the initial problem of modular product family in support of enterprise data.Moreover,based on prediction of technology importance and the new function module-technical matrix(FMTM),the conceptual planning of product family is obtained by calculating the diversity of function modules of conceptual product family according to platform ratio.An analysis example of product family of small wheel loader show the effectiveness of the method.

Method to aid product innovation by TRIZ, DSM and patent knowledge

For effectively use patents as information resource for aiding product innovation and avoid patent infringement, a method using patent knowledge based on Design Structure Matrix (DSM) and Theory of Innovative Problem Solving (TRIZ) is proposed. First the couple relationship between different components in objective patent of product is analyzed by DSM. Next deep knowledge of component which has least couple relationship with other components and lower restriction of creation is acquired from patent. Last the component is redesigned by TRIZ according to the design requirements. The method is illustrated by the innovation design of an ATV with shock-absorption function.

Identification of Cabin Noise Source Based on Wavelet Transform

In order to solve the problem of error and abstract in the identification process caused by current wavelet methods using grayscale to identify noise sources, a cabin noise source identification method based on wavelet transform(WT) was proposed. Firstly, multi-wavelet reconstruction signals were constructed from original time-domain signals through Matlab Wavelet Toolbox. Secondly, the eigenvectors were defined by calculating the energy value of reconstructed signals at all levels. And the correlation coefficients between cabin noise signal and other signals were obtained by these eigenvectors. Then the extent of vibration or noise energy radiation influence on the cabin noise was estimated by the size of correlation coefficients. Finally, an example was also given to show the effectiveness of the method.