The Degree Of Freedom And Workspace Analysis Of End Platform Of Hybrid Mechanism Composed Of 3-RPS And 3-SPR Mechanism

The hybrid mechanism combines the advantages of the series mechanism and the parallel mechanism.The large working space,compact structure,rapid dynamic response characteristics,and the high speed movement make it has wide application prospect in aerospace,medical equipments and CNC machine tools.In this paper,a kind of hybrid mechanism composed of 3-RPS and3-SPR mechanism is used as the object of study.Through the analysis of the constrained screw of the hybrid mechanism,the problem of the degree of freedom of the hybrid mechanism is discussed.The research results of hybrid mechanism are of great significance to its research and application.The main contents of this paper are as follows:Firstly,a class of two-layer hybrid mechanism composed of 3-RPS and3-SPR mechanism is introduced.Based on the screw system and the order theorem of the screw system,the method of solving the degree of freedom of such mechanism is obtained.The linear space intersection problem is discussed by different methods,and the constraint condition of the two-layer hybrid mechanism is obtained.Then,the degree of freedom of the(3-SPR)+(3-RPS)mechanism and the(3-RPS)+(3-SPR)mechanism is analyzed by the inverse operation of the constrained screw.Finally,a numerical example of the 3-SPR+ 3-RPS mechanism is given to verify the result of the intersection of constraint screw.Secondly,a mixed hybrid mechanism composed of 3-SPR and 3-RPS mechanism is introduced.Based on the research results of(3-SPR)+(3-RPS)and(3-RPS)+(3-SPR)mechanism,the number and property of degrees of freedom of seven different hybrid mechanisms are analyzed.The input mode and the input number of the two hybrid mechanisms are determined.Finally,a solution system suitable for working space of multi-layer hybrid mechanism is established by using Visual Basic language and CAD software secondary development technology.The working space solution system is suitable for multi-layer type of linear drive,angle drive and hybrid drive.In this paper,the concrete steps of the workspace solution system are given,and the feasibility of the system is verified by some examples.