Study On The Bio-inspired Mixed Phase Activated Flexible Arm

Water Hydraulic Flexible Arm(WHFA)is one of the most popular biomimetic actuators,showing good flexible structure characteristics and environmentally friendly advantages.In particular,their water hydraulic actuators offers the similar force to the oil ones while takes lower energy resources and lower finance resources.As the excellent driving performance,WHFAs are widely used in the field of food,medical,robot and automatic production line,especially suitable for a variety of works under the unstructured environment,such as in the deep ocean operation,which has brought great economic and social benefit.The working principle of the hydrostatic skeleton of leech has been researched and the biomimetic model has been developed based on the theory of bionic design.Then a new kind of Mixed Phase Activated Flexible Arm(MPFA)has been presented on the basis of the structure of Water Hydraulic Muscle(WHM).Themixed phase are composed of low density solids and water which reducing the gravity of the overall structure that under high injected pressure significantly.At the same time,the rigid characters of the solids improves the anti-bending-moment capacity of the overall structure that under low injected pressure.The structure presented in this paper is composed of some modules in series,and the module is composed of three flexible units in parallel.This unique structure is more security and can be easily installed and modified.The flexible unit is analysed in the curved plane coordinates,by which the length,the diameter and the bending angle of the flexible unit are calculated to estimate the deformation and the space position.And then the same calculation is utilized in the MPFA.A three-dimensional model of MPFA is built by ProE and the simulation is carried out by ANSYS Workbench in which the structure is established as the hyperelastic model.The relationship between the strain and the stress are obtained with the changing of the structure size.Still further,a multi-objective parameter optimization function is established to determine the structure parameters,on purpose of low stress,light weight and large deformation while the arm working.After that the structure is simulated under different injected pressure,the strain and the stress generated are obtained respectively.At last,the design of experiment(DOE)is applied and the appropriate experimental equipment is chosen on the basis of the above theoretical analysis.The experiment contains three parts of study between MPFA and WHFA,which are the stiffness of the structure,the workload response and the load-deformation relationship.Furthermore,MPFA is set to thereal work condition to research the load capability and the work space.