Study On Structure Design And Stability Of Quadruped Chassis For Forestland Installed Barycenter Adjustable Mechanism

The intelligent degree of forest management and protection in China is gradually improved,including the use of mechanical equipment instead of human resources to complete the forest ecological environment monitoring,information collection,forest mapping and resource supervision etc.to improve the working efficiency and reduce the artificial error.This paper designs a legged chassis for forestland installed barycenter adjustable mechanism,which is mainly used to load light-duty equipment such as forest mapping and information collection.Each leg of the legged chassis moves independently and can realize various movements and postures according to the foot trajectory planning.Compared with the wheeled chassis and crawler chassis of the traditional forestry machinery,the legged chassis has better terrain adaptability and trafficability.Also,the barycenter adjustment mechanism can adjust the chassis barycenter according to the terrain,conducive to improve the stability of the chassis moving in the forestland.The main contents,results and innovations of this paper include the following aspects:1.Kwon3 D motion acquisition system and high-speed camera method is used to record and analyze the motion characteristic of goats climbing slope steps with different inclination,and the mathematical model of the linear relationship between joint angle,foot trajectory and time is established.2.A legged chassis for forestland with adjustable barycenter is proposed based on motion characteristics and simplified structure of goat.The correlation between the chassis barycenter and the counterweight adjustment parameters is analyzed,and the position model of chassis barycenter is established.The movement space of the chassis leg is calculated,the forward and inverse kinematics models are established,and the Jacobian matrix is obtained.The dynamics of a single leg is analyzed,and the simulation experiment is completed.3.The gait planning of chassis is studied according to the gait planning method and barycenter adjustment,and the gait sequence and counterweight adjustment process are determined.Based on the goat foot trajectory model,compound cycloid method is adopted to plan the foot trajectory,the simulation results illustrate the feasibility of gait planning and trajectory planning.4.The stability of the chassis with adjustable barycenter is studied.Based on the normalized energy stability margin,the correlation between slope inclination,chassis barycenter height and the overall stability margin is studied.According to the stability margin,the stable region of chassis on slope is studied,and an adjustment method of barycenter adjustment is proposed.The correlation model between the parameter value of the barycenter adjustment mechanism and the stability margin is established,and the optimal parameters are determined.The results show that the above method can effectively adjust the center of mass position and improve the stability margin.5.Based on the inverse kinematics and the foot trajectory,the correctness of the chassis movement and barycenter adjustment is verified by simulation test through Matlab and Adams,and the results are analyzed.The physical prototype is processed and assembled,the measured parameters of the prototype leg motion space are consistent with the theoretical value.Lab VIEW is used to write control program and the single leg test experiment is completed.In addition,the static stability test of the forestry chassis is completed.This paper proposes a new idea and method for the application of forestry machinery,and provides a theoretical and technical basis for the further improvement and development of the chassis for forestland.