Research Of The Gait Planning And Modeling Simulation For The Forestry Quadruped Walking Machine

With the rapid economic development, the demands of automated machining are becoming increasingly high. In order to improve the forestry operation efficiency, researchers begin to pay more attention to the mechanization and automation of forestry machinery. However, due to the complexity of the forest terrain conditions and operating environment in our country, there are many drawbacks in crawler and wheeled mobile machinery. For example, wheeled mobile machinery is not suitable for rugged or soft terrain conditions, and the crawler mobile machinery has poor obstacle capacity. So it is necessary to design a kind of walking machine which can walk in the forest with complex terrain conditions in order to meet the market demands. Recently, in the field of robotics research researchers are giving more and more focus on multi-legged walking machines, which becomes an important branch of robotics research. Nowadays, two-foot, quadruped and six-foot walking machines are familiar to us. And among them, the quadruped walking machine has the advantages of the simple structure, good stability and strong carrying capacity, and it not only can achieve static slow walk, but also can achieve dynamic high velocity. This paper proposes a kind of quadruped walking machines for forestry operations with the program of its mechanical structure, and conducts in-depth analysis and research.This paper, on the basis of the analysis and summary of the history and present research of the quadruped walking machine in the world, proposes a structural model of a new kind of forestry quadruped walking machine based on the principle of the bionics, and gives the total design scheme. Conducting gait planning for the quadruped walking machine, identifying the dynamic gait of diagonal trotting, and its gait stability has been investigated to find out the main factors that influence its stability.In addition, the kinematic model of forestry quadruped walking machine has been established, kinematics problem of the quadruped walking machine via the D-H method has been studied, a positive solution of the equation has been given and further the motion characteristics of the walking machine have been analyzed to obtain the speed Jacobian of the forestry quadruped walking machine. Then in this paper, the dynamic model of the quadruped walking machine has been established, and the dynamic equation of the leg link mechanism of the quadruped walking machine with the lagrange functional balance method has been analyzed and deduced and part of which has been solved.With virtual prototyping technology, a three-dimensional virtual model of forestry quadruped walking machine in Solid works has been established, the trotting gait simulation has been given, and the feasibility of motion planning has been verified, and these provide the basis for improvement of the whole structure. In addition, the three-dimensional model of walking machine has been imported into ADAMS software, and then physical parameters have been added according to the actual situation to give motion simulation research for the quadruped walking machine. What’s more, the forestry quadruped walking machine that studied in this paper has been well manufactured and assembled, and been given the gait test in the laboratory. The experiment shows that the forestry quadruped walking machine has basically met the design requirements of gait and step length and obstacle height.Finally, in this paper, a study for the shell structural characteristics of the forestry quadruped walking machine has been conducted. And according to the research, the external shell modeling of the walking machine has been designed, and the mechanical model of the shell has been established, the strength of the compacts in the role of the collision force has been analyzed, and the displacement equation and the impact force equation of thin wood veneer shell have been obtained and the position of the maximum displacement deformation has been confirmed. The material of the shell is a innovation which breaks the tradition, using thin wood veneer. Therefore, not only the weight of the whole machine has been reduced, but also it can contribute to surface modeling, and the purposes of environmental conservation and beautification of the appearance have been achieved.The study of this paper provides a theoretical basis for the development of forestry walking machinery. In the future, the forestry mechanization will become more and more perfect, the forestry walking machines with good obstacle crossing ability must have broad market prospects.