| Hydraulic excavator is a kind of earth moving machine, it can excavate foundation pit and groove and do the operation of surface stripping in building construction, water conservancy engineering and mining. Thus hydraulic excavator has very important position in all kinds of engineering machine. If replacing its work device, hydraulic excavator also can be used for crushing, loading and unloading, lifting, piling and demolition etc. Therefore,the design quality of the working device determines the performance of the whole machine.Failure of working device is due to the unreasonable design in a large extent, because of the traditional methods and means for design can’t meet with the needs of engineering. Based on the common problems of optimization design for kinematic and dynamic properties in working device of excavator, a certain type of backhoe hydraulic excavator is used for the research object in this paper. The operation performance of the working device were visualized and analyzed and the comprehensive kinematic optimizations for parameters of performance and structure are done by programming. The GUI design in MATLAB software is used for accomplishing the module ‘analysis of visualization and optimization design for the working device in the backhoe excavator’. The main works of research are shown as follows:(1) The kinematics mathematical model of the working device is established by using the method of odd transformation for Denavit-Hartenberg coordinate, and the function expression of the position and orientation ?,,?TX Y Z for the key hinge points are obtained.Besides, the motion state of three parts in the working device is analyzed according to the method of geometric. The D-H global coordinate system is established based on the relationship between the hinge points. The dynamics model of working device is established by using the method of Lagrange modeling and its expression of function is solved. The programs for kinematics simulation are written and GUI interface is designed in the environment of MATLAB. It provides necessary preparation for analysis of visual performance and comprehensive optimization of hybrid algorithm in the follow-up section.(2) In Pro/E, the classical design method of bottom-up modeling is used for constructing the three-dimensional model of working device. Virtual prototype of working device is established by importing the assembly in Adams. The kinematics simulations and experiments of virtual prototyping are done. Besides, GUI module of movement simulation is written in MATLAB through the kinematics mathematical model, results of simulation are consistent with the virtual prototype.(3) The theoretical digging force models of bucket rod hydraulic cylinder and bucket hydraulic cylinder are established. With considerations of the constraints such as the resistance of digging, the blocking of the oil cylinder, the stability of whole machine and ground adhesion properties etc. The theoretical digging force models for the whole machine of bucket rod excavation and bucket mining are established. The maximum stress at the main hinge point in the theoretical digging force model for the whole machine is analyzed and corresponding calculation module in GUI MATLAB is programmed. It provides an analytical tool and design method for the visual analysis of mining performance. Taking a certain type of excavator as an example, relevant analyses are done.(4) The comprehensive optimization mathematical model for working device is established, the optimization module of working device is programmed under the environment of MATLAB by using the penalty function of simulated annealing hybrid algorithm. Besides the problems that are proposed by the analysis of cloud chart are optimized. The results of optimization show that the overall mean digging force is significantly improved, at the same time, the atresia restricted area is reduced, the active mining area is expanded and the operation performance of machine is greatly improved.Programming the optimization design module of working device into the GUI user interface to make the optimization design becomes modular and simple. The cloud chart module of mining stress and motion simulation module are called through the function handler to compare the results of operating performance before and after the optimization by visualize graphics. The change of operating performance of working device can be obtained simple and intuitive understanding. It can provide theoretical basis for the following works. |
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