| Robotic hand plays an important role in daily life and engineering.However,when the robotic hand is grasping for large-sized objects,it often faces problems such as excessive volume,inconvenience in transportation or enough grasping force and rigidity.This paper presents a novel quadrangular truss-shaped deployable robotic manipulator with metamorphic mobility,which has higher stiffness than the traditional serial robotic manipulator and therefore suitable for grasping of the large-scale unknown objects.Firstly,a quadrangular prism mechanism module is introduced as the basic unit of robotic manipulator,general procedures for designing this type of robotic manipulator is provided.The grasping simulation in Inventor is also conducted,which shows that the proposed manipulator has shape adaptability to different types of the grasping objects.The drive of the mechanism and the limit joints were designed so that the mechanism can be successfully driven to verify its feasibility.Secondary,the mobility of the basic metamorphic mechanism module in this kind of robotic manipulator is analyzed by using the general Grübler-Kutzbach equation.Thirdly,Kinematics of the robotic hand is provided and the singularity of unit is analyzed,which demonstrate it is non-singular robotic hand.The workspace for the proposed manipulator consisting of six identical units is also analyzed,which demonstrates that the manipulator has large reachable space,the kinematic equation of the proposed model is also analyzed.Finally,the mechanism dynamics and statics are established based on Lagrange equation and the virtual work theorem.The relationship between the stiffness coefficient of the mechanism as the angle rotates is studied by using the virtual work theorem.A set of standards for evaluating the performance of robotic hand is proposed.The simulation of grasping is carried out and the evaluations are given according to this standard. |
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