Analysis On Motion Characteristics And Design Of A Novel Hybrid Redundant Humanoid Robotic Arm

As the most common and most important manupulator in the field of human-machine integration,the humanoid robotic arm(HRA)can not only complete a series of activities such as welding,handling,and throwing,but also cooperate with humans to complete specific tasks outside the structured environment of the manufacturing plant.With the development of production requirements and changes in service objects,the requirements for sensitivity and operability of HRA are becoming higher and higher.Therefore,in order to solve the limitations of the inherent characteristics of typical robotic arms and realize the design and application of lightweight smart arms,this dissertation proposes a serial-parallel hybrid redundant HRA,and carries out related research on the kinematics,dynamics and performance optimization of serial-parallel hybrid mechanisms.The main contents are as follows:Based on the anatomical analysis of the movement of the human arm,the design indexes of the HRA are set,and the joint arrangement and the degree of freedom(DOF)of the robotic arm are assigned according to the G_F theory of configuration synthesis.The humanoid shoulder joint(HSJ)is modeled on a 2-DOF spherical 5R parallel mechanism,the humanoid elbow joint(HEJ)is selected as a 3-DOF series mechanism,and the humanoid wrist joint(HWJ)is modeled on a 3-DOF 3-RRP parallel mechanism.According to the modified Grübler-Kutzbach formula,the nature of the DOF of each joint is analyzed,and it is verified that the selected joint configuration can meet the motion requirements of the design indexes.The modern mathematical tools(such as screw theory,exponential product formula,Lie Groups Lie Algebras and the principle of virtual work,etc.)are used to conduct research on the kinematics analysis of serial-parallel hybrid mechanisms,and a generalized analysis method is obtained.According to the generalized coordinate system and exponential product formula,the forward displacement solution is established.The inverse displacement problem is solved by using Paden-Kahan sub-problems,and the identification problem of the inverse solution is analyzed.Based on screw theory and Lie Groups Lie Algebras,the Jacobian matrix and the Hasson matrix of kinematics transfer are derived.Taking the proposed serial-parallel hybrid redundant HRA as an example,the kinematics analysis process of hybrid mechanisms is demonstrated in detail,and it provides a theoretical basis for dynamics modeling and performance optimization.Using the direct and simple kinematics analysis model established in this dissertation,the kinematic transfer matrix of the rod is obtained,and the standardized dynamics model formula of the HRA is derived based on the principle of virtual work.According to three different motion conditions,the contribution characteristics of acceleration torque,Coriolis torque and gravity torque in the dynamics model are analyzed.The simulation results show that the contributions of Coriolis force and acceleration cannot be simply ignored in the simplified calculation of the dynamic model,which provides a theoretical basis for parameter identification of the dynamic model.According to the motion transfer characteristics of the proposed HRA,the performance evaluation indexes of the mechanism are set up in a distributed manner,which avoids the complexity and discomfort of the global index of the whole machine.The boundary search method is used to draw the workspace,and the orientation space of the HSJ,the position space of the HEJ and the active orientation space of the end platform are analyzed emphatically.The heterogeneity of the transfer indexes of serial and parallel mechanisms is studied,and the transfer indexes of the parallel HSJ and parallel HWJ and the linear velocity performance index of the whole machine are set respectivel.Aiming at the problem of multi-parameter optimization design,a multi-parameter plane model is proposed to realize the visualization optimization design.Taking the workspace and transfer performance as evaluation indexes,based on the multi-parameter plane model,the structural parameter optimization results of the HRA are given,and the structure parameters of the joints of the HRA are finally determined by combining the requirements of the compact mechanism and the processing and assembly process.Based on the theoretical analysis results of this dissertation,a physical prototype of the HRA is designed and assembled.According to the existing experimental conditions,a motion test plan is set up,the corresponding experimental research platform is built,and a test control system is established based on the motion control mode of the drive motor.Through the analysis of the experimental research data,the rationality of the physical prototype configuration and the consistency of its motion performance with the theoretical analysis are verified.Finally,the shortcomings of the current research are summarized and the directions for future research are pointed out.