The Research On Excavator Modeling And Weighing Algorithm Based On Kane Method

When the traditional hydraulic excavator works,it will load the excavated materials into the truck,and use the weighbridge to measure the weight of the materials that need to be weighed.This kind of weighing method will prolong the working time of hydraulic excavator,cause unnecessary wear and tear of excavator and fatigue of operator.The hydraulic excavator with automatic weighing system does not need to be weighed by a third party,which saves working time and helps to realize intelligent excavator.It is the development direction of excavator products in the future.According to the above background,this paper designs a hydraulic excavator weighing algorithm,which uses the sensors installed on the boom,stick,bucket and the corresponding hydraulic cylinder of the excavator to collect data in real time,so as to realize the dynamic weighing of the hydraulic excavator.Firstly,combined with the structural characteristics of the hydraulic excavator,the dynamic analysis of the hydraulic excavator is carried out by using Kane equation,which simplifies the modeling process and establishes the dynamic model of the excavator.Secondly,according to the dynamic model,the parameter identification formula is derived and transformed into the least square format,and the weighing parameter set containing six parameters is obtained.In order to avoid the error caused by recursion of six weighing parameters at the same time,this paper adopts two-stage identification method to reduce the number of parameters recursion at the same time and improve the identification accuracy.Thirdly,the identified weighing parameters are substituted into the dynamic model as known quantities,and the weighing formula is derived.Combined with the recursive least square method,the online estimation of load quality is realized,and the weighing algorithm is designed.In order to optimize the weighing algorithm,according to the characteristics that the inclination sensor developed by the laboratory can measure the angle,angular velocity and acceleration of installation position in real time,the functional relationship between the angular acceleration of boom,stick and bucket joints and the data measured by the above inclination sensor is established,so as to avoid using the difference method to calculate the angular acceleration of joints,improve the measurement accuracy of angular acceleration and reduce the weighing error.Finally,in order to verify the effectiveness of the weighing algorithm,the experiment is carried out.The experiment platform is built with the designed weighing algorithm,the parameter identification experiment is designed,and the simulation program is written by MATLAB software,and the experimental data are analyzed and the relevant weighing parameters are identified online.The weighing experiments under different loads are designed by using weighing formula.The difference between the estimated value of load mass and the actual value of load mass is compared to observe the weighing effect.The weighing algorithm of hydraulic excavator designed in this paper has been verified by experiments that the weighing error is less than 8% when weighing more than 60 kg materials,and it still maintains a high weighing accuracy when the excavator works dynamically,which has a certain engineering practical value for the intelligent development of the excavator.