Study On The Optimized Dynamic Load Distribution For Series-parallel Hybrid Humanoid Arm

At present,the structure of most humanoid arms is dominated by a tandem mechanism,which has the problems of cumulative error,small carrying capacity and poor dynamic characteristics.The parallel mechanism has the advantages of strong bearing capacity,small motion inertia and good dynamic characteristics,which effectively makes up for the shortcomings of the tandem mechanism.In order to overcome the defects of the present humanoid arms,a novel serial-parallel hybrid humanoid arm is proposed.The humanoid arm is studied,including the kinematics,dynamics and dynamic load distribution etc.The following work has been achieved:(1)A novel serial-parallel hybrid humanoid arm is proposed,and the spherical 5R parallel mechanism,4-bar mechanism and 3-UPS/S parallel mechanism are adopted as the shoulder,elbow and wrist joint.3-DOF shoulder joint,1-DOF elbow joint and 3-DOF wrist joint are connected in series.The humanoid arm has a lot of advantages of the parallel and series mechanisms.(2)The kinematic model and dynamic model of shoulder joint and wrist joint is established.The dynamic performance evaluation index and force mapping performance evaluation index are defined.And the distribution of each performance index in the working space is drawn and analyzed.(3)The kinematic model and dynamic model of the series-parallel hybrid humanoid arm is established.The dynamic performance evaluation index and force mapping performance evaluation index are defined.And the distribution of each performance index in the working space is drawn and analyzed.(4)An optimization method of dynamic load distribution of the humanoid arm is proposed.The trajectory equation with the best overall performance is established.By considering the time,energy consumption and stability,the generalized time optimization objective is defined.The shortest generalized time for optimal trajectory motion is obtained by genetic algorithm.In this paper,the optimization method of dynamic load distribution of the humanoid arm is studied.And the distribution of the dynamic performance evaluation index and the force mapping performance evaluation index in workspace are studied.The optimal trajectory and the shortest generalized time is obtained.These research results provide a theoretical basis for the engineering application of humanoid arms.