Mechanism optimal design of backhoe hydraulic excavator working device based on digging paths

In order to solve the problem that hydraulic excavator in the real working process cannot meet the design requirements and reveals insufficient digging force, a new method on mechanism optimal design of backhoe hydraulic excavator working device based on digging paths is introduced and discussed in this paper. Considering the characteristics of consecutive digging process of hydraulic excavator, a digging path is composed of bucket digging trajectories and arm digging trajectories. The feasible working region is divided into a series of uniform paths according to the working position of boom. The practical digging performance of excavator is evaluated based on the digging force parameters under combined work condition of the discrete points on the digging paths. It is turned out that the method is more accurate to analyze excavator’s real-world digging performance via the analysis of some practical cases. Based on the new digging performance analysis method, the optimization mathematical model is built to ensure the digging force under combined work condition and the average digging force of every operating path as big as possible. The layout design of hinge position on the working device is optimized through genetic algorithm. The optimization result shows that a certain model of an excavator’s maximum digging force on the customary digging paths is improved by 10% and the average digging force is improved by 4% after the optimization on the working device of the excavator with weak digging force.