Design And Analysis Of Series-parallel Connection 4-DOF Torso Of A Biped Robot

As a highly complex comprehensive system,biped robot involves mechanism,bionics,artificial intelligence,mathematical method and many other disciplines.As a new challenging research direction,a lot of work had been done by research institutions and universities at home and abroad these years.Aiming at biped robot,this article put forward a new kind of 4-DOF series-parallel structure torso,and a concrete analysis of this mechanism was made.The main research contents of this paper were as follows.First of all,the structure and motion mechanism of the human body were introduced in detail.The design requirements of the biped robot's torso configuration were analyzed according to the principle of bionics.Summing up research achievements of domestic and foreign predecessors,many current existing problems were found.Therefore,a new kind of 4-DOF series-parallel structure torso in biped robot was proposed.Secondly,the kinematics of biped robot's torso structure was analyzed.A schematic of the torso mechanism was finally got on the basis of the analysis of the foregoing certain torso configuration.The kinematics model of the parallel mechanism was built,where we could obtain the driving mechanism's displacement by solving the problem of inverse kinematic,taking advantage of the inter-coordinate relations of set locations and positions.Considering that the solution process of the positive kinematic of the parallel mechanism is more complicated,we transformed it into an optimization problem to solve.Then plot and analyze the related curve which described that the torso's rotation angle varied with the changing of the bar's length.Due to the series structure,the influence of the fluctuation of the center of gravity was mainly considered and the curve was plotted which described movement of the center of gravity,which could verify the selected type of the compensation device in the vertical direction as mentioned above.Thirdly,the torso configuration and structure design in biped robot was introduced in detail,including selecting types of the driving system and electrical components,doing the preliminary design and material reducing design at the chest structure,specifically designing and analyzing the torso,and designing anti-impact structure of the torso.At the same time,non-impact trajectory was planned.And the entity prototype simulation of the torso in biped robot was done by taking advantage of the professional analysis software of mechanical system dynamics.The dynamic simulations for the three degree of freedom of the torso in biped robot,including pitching,rolling and moving in the vertical direction,were all done,which verified the reasonability of the structure design.Finally,the whole paper was summarized and the better prospect was made for the future research direction.