Research On Motion Characteristics And Gait Trajectory Planning Of Bionic Tree Climbing Robot

Bionic robots are a rapidly developing field of research,their main research directions are prototype design,development,and applications,bionic robots have been widely researched and applied in many fields,but there are few studies on tree climbing robots,at the same time,aiming at the current problems of mechanization,low level of operation,shortage of mechanization and automation in forestry,agriculture,fruit picking,etc.This paper combined with the characteristics of primate tree climbing,carried out in-depth theoretical analysis of a bionic tree climbing robot studied,the main contents include:Firstly,the overall structure design idea and climbing gait of the tree climbing robot are analyzed,and gait simulation and prototype physical model made are carried out.On this basis,the number of degrees of freedom of the legs mechanism is calculated using the screw theory,and the D-H principle is used to solve the forward and inverse kinematics equations of each leg based on the angle change of the waist of the frame,and a specific calculation example is given and simulated.According to the singularity principle of the parallel mechanism,the singularity analysis and classification of the leg mechanism are carried out.The vector product method is used to solve the speed Jacobian matrix of the supporting foot,and the Jacobian matrix of the speed of the swinging foot is obtained by used the direct differential method,and established the mapping relationship expression between foot end space velocity and joint velocity.In addition,the functional relationship between hydraulic cylinder driving displacement and the angle is determined.Secondly,combining the primate tree climbing gait and the quadruped climbing robot gait,the walk gait and trot gait of the tree climbing robot studied in this paper are obtained and analyzed specifically.The acceleration trigonometric function guidance method and the low contact impact gait planning method with particular attention on foot motion trajectory are used to calculate the trajectory planning of the supporting foot-end and swinging foot-end respectively,and the simulation analysis is carried out.The calculation and simulation of the movement trajectory in the lateral direction.And the joint trajectory of each swinging foot is calculated by using cubic polynomial and quintic polynomial interpolation,and the joint trajectory equation is established,and the simulation analysis is carried out.Furthermore,static balance analysis is performed on the overall force of the tree climbing robot,and its load capacity is calculated and verified,finally,the tree climbing robot is subjected to path selection analysis and obstacle angle calculation,and simulation analysis is performed.Thirdly,the motion analysis of the leg mechanism of the tree climbing robot is carried out,and the relationship between the length of the links and the joints driving angle under the four conditions of different numbers of drive motors are obtained,and the value range of driving displacement and angle of each joint is obtained,and numerical simulation analysis is carried out.The genetic algorithm is used to optimize the design of the length and angle parameters of the legs based on the three aspects of avoiding singular position,friction coefficient and avoiding leg interference,at the same time,specific calculation examples and simulation analysis are given.Finally,according to the optimized links length and angle,numerical simulation analysis is carried out on the foot-reachable working space,and the relationship between the length and angle of the optimized links based on the friction coefficient and avoided leg interference is analyzed by numerical simulation,and then the joint trajectory equations obtained by using differentpolynomial interpolation methods are respectively carried out numerical simulation analysis.The virtual prototype technology is use to simulate the kinematics of the tree climbing robot,and compare it with the corresponding numerical simulation results to verify the accuracy of the kinematics modeling.