Configuration Design And Motion Analysis Of Centrally Driven Humanoid Robotic Arm

Rigid humanoid robot arm,as an important actuator that can best fit the configuration and motion characteristics of the human arm,has been widely used in the field of humanoid robot because of its characteristics of easy manufacturing and installation,stable motion and accurate motion control.It performs diversified target tasks and has a broad application background.Due to the limitation of space and transmission distance,the driving source of most rigid humanoid manipulator is dispersed in each moving joint,which leads to the increase of joint size and the weight of the whole arm,the increase of motion inertia,and the decrease of motion rapidity and flexibility At the same time,some of the manipulator also has the link offset at the joint,which leads to the structure offset phenomenon between adjacent arm segments.The offset distance will increase the complexity of kinematics modeling solution and the stability of actual motion.Starting from centralization of driving device and integration of moving joints,a4-DOF rigid serial humanoid manipulator with driving motors concentrated on the upper arm is designed in this paper,in which the two DOF of the shoulder are directly driven,and the two DOF of the elbow are indirectly driven,and the elbow is driven by two sets of independent four-link mechanism as the transmission device.This design of structure can reduce the inertia of motion,improve the accuracy of movement,achieve the centralization of driving source,through the configuration design to make the elbow more compact,can also avoid the structure bias phenomenon,improve the movement stability of the manipulator.This paper focuses on the configuration design of the manipulator,the analysis of kinematics and dynamics,the integration of experimental prototypes and the test of motion,as follows:(1)A new 4-DOF rigid serial humanoid manipulator with centralized drive was proposed,the configuration characteristics of the transmission mechanism were analyzed,and the humanoid motion form of the manipulator was demonstrated.(2)The equivalent motion model of the manipulator is presented,and the forward and inverse kinematics process of the manipulator is analyzed.The velocity Jacobian matrix is constructed and the singularity of motion is analyzed theoretically.The workspace of the manipulator was drawn,and flexibility analysis was carried out to determine the appropriate kinematic dimensions of the big and small arms and the range of joint motion.The path planning analysis was carried out.The joint angles were optimized and selected according to different optimization methods,and the interpolation calculation was carried out to obtain the trajectory of different joint angles and the motion path of the end of the manipulator.The performance indexes under the two paths were compared and analyzed.(3)The dynamics theory of the manipulator was analyzed,and the mathematical relationship between the output torque of each driving motor and the joint Angle was obtained by Lagrange method.The dynamic simulation software is used to analyze the variation of motor performance parameters during the movement of the manipulator,and then the load capacity of the manipulator under dynamic and static conditions is analyzed.(4)The experimental prototype was developed to realize various motion forms of the manipulator;The test results were compared with the theoretical analysis and dynamic simulation results.These studies provide important reference for later optimization.