| Excavator working device is the main direct performer of the operating conditions. The rationality of the structure of excavator working device links closely to the excavator machine working performance, and the optimization design of the excavator working device mechanism has always been a key problem to improve the excavator machine working performance. Digging working conditions of hydraulic excavator are complicated, and the system efficiency is very low. Moreover, the domestic hydraulic components are lack and manufacturing quality is not stable. However, most of high pressure hydraulic parts still rely on foreign imports. In this topic, the mechanism optimization method fom the point of view of mechanism is used to reduce pressure and flow rate of hydraulic system, in the premise of meeting the requirements of the existing conditions. This topic tries something new in reducing the energy loss and improving the service life of the domestic hydraulic system, and enlarging the using range of domestic hydraulic system, and improving the domestic excavator working device mechanism design technology.The content of this paper are as follows.(1)The motion analysis of Active Groups with offset of grade â…¡ (RPRR) is presented. And the Active Groups Method and Assur Group Method is used to analyze the direct kinematics of excavator working device, and the assur groups method is used to analyze the inverse kinematics analysis of the excavator working device.(2)The concept of excavator working device motion planning is put forward. The cylinder movement planning method and bucket movement planning method are proposed, which are respectively based on direct kinematics and inverse kinematics. And the motion of excavator working device is planned.(3)The motion and force analysis of the offset type oscillating hydraulic cylinder are proposed to research the influence of the offset to the flow rate and pressure of the hydraulic cylinder. And the offset of the oscillating hydraulic cylinder is added as optimization variables, and the constraint conditions of the offset are given.(4)Through the analysis of the working condition and digging resistance of excavator, the foundation for determining the optimal working condition of the optimization of the excavator working mechanism is laid. Through the static analysis of excavator working device, the relationship among the excavating force, the cylinder thrust of working device and location of the hinge points are obtianed.(5)The optimization conditions of the excavator working device are determined. By working in the main operationg area, set the maximum input power of the cylinder of the working device being minimum as the optmizing goal, to establishe the optimization methematical model of excavator working device. And the MATLAB software Optimization Toolbox is used to optimize the optimization mathematical model.(6)An optimization example of optimization of WY200 type hydraulic backhoe excavator working device mechanism is given, to verify the optimization theory of working device mechanism in this topic. |
