| With the continuous improvement of industrial technology,the research of mechanism has also been flourishing.In recent years,the mechanical components have been extensively developed in the aspects of light weight,high efficiency and high positioning accuracy.The unique feature of the Cable-driven Parallel Manipulator(CDPM)approach is to use cables and winches instead of parallel links as actuators.It combines with the characteristics of parallel structure and formed a new flexible low quality,low inertia,high accuracy and high load capacity of the cable parallel mechanism,which becomes a focus of attention at home and abroad.In this paper,a new type of three flexible cable driven parallel mechanism with a restraint component was studied,and supported by rigid rods,a rigid-flexible coupling parallel mechanism is formed.The main tasks and findings of this paper are summarized below:(1)Theoretical research.The configuration of the mechanism is studied,and the degree of freedom of the mechanism is analyzed and discussed.The cable-driven parallel mechanism adopts the cable instead of the connecting rod and relies on the redundant actuation to realize the complete constraint.The kinematic model of the mechanism is established using closed vector method.Using MATLAB Software,the rotation of motion platform around x' and y' axes was simulated,and the curve of the movement of the cable was obtained.The work space of the cable-driven parallel mechanism was studied and its movement was analyzed based on the area that can be reached by the end of the unit normal vector of the motion platform.According to the movement of the mechanism,the trajectory planning of the mechanism was carried out,and simulated using MATLAB.The static equilibrium equation is established for the force analysis of the motion platform and the force Jacobian matrix is solved.Kinetic model is the basis of control system design,and the dynamic model of the system includes the establishment of dynamic equations of motion platform and actuators.The deformation of the cable-driven parallel mechanism is related to the stiffness of the mechanism and the size of the force.The factors that influence the stiffness of the mechanism,especially the cables,are analyzed.The stiffness matrix is established and its evaluation index is obtained.(2)Simulation modeling.This part includes modeling of rigid body structure and flexible cable.SolidWorks software was used to model the moving platform,the fixed platform and the restrained bracing rod connected to the above two platforms and assembling them into a binding ligand.Based on ADAMS software,the soft cable part of the flexible cable driven parallel mechanism was modeled.Several different modeling methods are discussed,and the modeling process of ADAMS/Machinery Cable module and Bushing method is emphatically analyzed.The model of the flexible cable driven parallel mechanism was simulated,and the mechanism was rotated around the two axes of x' and y' respectively,and the continuous change curves of the flexible cables are obtained.The validity of the simulation is verified by comparing the simulation curves of the MATLAB.(3)Application development.The application of the cable-driven parallel mechanism is analyzed briefly,which was mainly discussed in two aspects.First,the winding types.Connecting the similar joints end to end,it can be applied to the bionic elephant nose mechanism and the bionic snake mechanism,etc.Two kinds of driving methods are designed for the mechanism.One is composed of three flexible cables to connect all the serial mechanism,and the control box control the overall movement of the mechanism;the other is a piecewise control box control,each joint has its own control box.Second,the load types.a new type of mechanism is formed by connecting the movement platform with other mechanisms.It can be applied to the bionic eye positioning mechanism,multi finger joint mechanism,bionic spine mechanism and medical ankle rehabilitation mechanism,etc.The force analysis was carried out on the loaded moving platform,and the simulation was carried out by MATLAB software. |
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