Analysis And Control System Research Of A New Type Of Overconstrained Five Degrees Of Freedom 2PRPU+PRPS Parallel Mechanism

The five-degree-of-freedom parallel mechanism demonstrates superior performance in terms of workspace,flexibility,and controllability compared to its three-degree-of-freedom and four-degree-of-freedom counterparts,enabling it to cover a larger operating range and meet the demands of more complex tasks.Although its flexibility and controllability are slightly inferior to six-degree-of-freedom parallel mechanisms,its simple structure results in lower manufacturing and maintenance costs.The five-degree-of-freedom parallel mechanism exhibits good adaptability in various practical applications,such as surface polishing and gear machining.In summary,the five-degree-of-freedom parallel mechanism achieves an effective balance between performance and cost,making it an ideal choice for widespread use in engineering fields.This thesis proposes a novel overconstrained 2PRPU+PRPS five-degree-offreedom parallel mechanism.The main research contents are as follows:(1)Detailed configuration description and analysis of the parallel mechanism were conducted.Firstly,the mechanism coordinate system was established,followed by the application of screw theory to analyze the constraint forces within the mechanism,determining the number of degrees of freedom and verifying the accuracy of the analysis results using the modified G-K formula.(2)Kinematic analysis of the parallel mechanism was carried out.The inverse solution equation of the mechanism was calculated using the vector method.Subsequently,a mapping between the driving velocity and acceleration and the motion platform velocity and acceleration was established,with MATLAB being used for the example calculations to obtain the displacement,velocity,and acceleration curves of the driving branches over time.The workspace of the mechanism was analyzed using the Monte Carlo method,and dexterity analysis was performed.(3)The dynamic model of the mechanism was established using the virtual work principle.MATLAB was used for example calculations of the dynamic model,yielding the time-varying curve of the driving force of the mechanism’s driving branches.(4)The 3D model of the parallel mechanism was created using Solid Works software and imported into Simulink to build a virtual prototype.Motion simulation was conducted in Simulink software,recording the displacement,velocity,acceleration,and driving force of the virtual prototype during the simulation process and comparing them with the results obtained from MATLAB.(5)A control system for the overconstrained five-degree-of-freedom parallel mechanism was designed in Twin CAT3 and connected to the virtual prototype simulation platform in Simulink for control simulation.The control program of the mechanism was tested in the virtual simulation interface,and the Twin CAT3 Scope View module recorded the simulation results of the driving branch displacement,velocity,acceleration,and driving force,which were compared with the simulation results in Simulink,thus verifying the feasibility of the software control system and laying a solid foundation for future physical prototype control experiments.