Research To Optimize The Digging Trajectory Of WK35 Cable Shovels And Analysis Of Random Vibration

Digging trajectory can affect the performance and productivity of cable shovels. Their running environment and load characteristic possess great randomness and uncertainty. They mainly include:soil characteristic has randomness; the working boundary condition and operation of cable shovel have uncertainty; the digging process is an irreversible physical process. The digging trajectory is the original question of design and the basis to build independent design system and digging theory. Therefore, this subject is under research through National 863 sub-project (No.2012AA062001). Moreover, the randomness of arm components concerns their stability, fatigue and service life while working. Thus, both of digging trajectory and the randomness of arm components are important research contents. It is significant in reality and theory for improving the working performance of cable shovel to discover optimal digging trajectory, research the vibration law of arm components.Represented by WK35, based on test data of onsite stripping, a kinematic model of working mechanism is built. On the calculating condition of 17 samples with a cycle of 45s and 13 samples with a cycle of 33s from 286 samples in total, the discrete motion curve points of bucket tip are reduced. In addition, all velocity, force and energy variables are calculated and stored in designated tables. Then, according to three criteria:soil volume in the bucket should meet the requirement of bucket volume when being putting out, the digging cycle should be reasonable, and the energy consumption of per unit soil volume in the bucket should be minimal, the suitable samples are screened. Among them, there are 6 samples with a cycle of 45s and 4 samples with a cycle of 33s. And 2 groups of actual trajectories including 10 samples in total are plotted. According to the shapes and positions of trajectories, the screened samples are rearranged and divided into different groups. Finally,3 optimal digging trajectories are obtained. The optimal digging trajectories of samples with a cycle of 45s are ρ= 11.16e03375θ and ρ=11.30e0276θ, while the optimal digging trajectory with a cycle of 33s is,ρ＝11.018e0.2459.Aiming for the random vibration question when cable shovels are working and considering that the driving caused by random factors and system variables are random, a dynamic response model is built. Then, dynamic responses are figured out and the question that whether cable damp is neglected or not doesn’t change the final vibration law is tested.To calculate key variables and optimal trajectories in the digging process quickly, accurately and in standard way, a software system is developed. This software can figure out process variables such as tangential and normal digging resistance, energy consumption, relief angle and material volume and representative optimal. Moreover, it can also plot curves and store final calculation results. Thus, the shortcoming of hand computation, such as being time-consuming and causing error easily, are avoided.Besides, the working efficiency is improved and the design cycle is also reduced.