Numerical Control Study Of A C-shaped Gantry Parallel Machine Tool With Two Redundant Drives

With the continuous exploration of parallel mechanism,redundant actuation has been confirmed to improve the singularity and increase the stiffness and stability of workspace.To further expand and regular the workspace of C-shaped Gantry Parallel Machine Tool(C-PMT),and improve the processing adaptability,in this thesis,a redundant drive is added to the original machine tool,thus the research on C-PMT with two redundant actuation is carried out.The dissertation focuses on the following aspects.Firstly,the kinematics and workspace are analyzed.Based on the parameters of C-PMT and linear module,the inverse kinematics,forward kinematics equations and Jacobian matrix are derived,and the method of forward solution is given.By using the method of limit boundary searching,the workspace of C-PMT when redundant sliders are located at different positions is obtained,and the workspace boundary of different sections is analyzed.Secondly,the method of trajectory planning in joint space is determined.Based on the proposed transmission angle constraint criterion and dexterity criterion,different planning methods are adopted for the two redundant drives according to the actual situation of C-PMT.The motion simulation results of MATLAB verify the feasibility of the planning methods.Then transmission system of the branched chain is analyzed.By converting the load torque and the moment of inertia to the shaft side of servo motor,motion equation of the system is derived.By using transfer function,mathematical model of the control system of branched chain is established and performance of the system is analyzed.Finally,configuration of the electrical appliance and the numerical control system is completed.Driving motor of the parallel branched chain and the redundant branched chain is selected.According to the open numerical control system of this thesis,the version,quantity and connection of numerical control host,shaft module,I/O module and electronic handwheel are analyzed,and the whole machine tool is debugged.Configuration of other electrical appliances is also analyzed.