Research On A Large Angle Swaying Test Platform With Folders

With the development of China's national defense and military industry,it is urgent to break the monopoly of foreign technology,and the development of high-performance motion simulator has been on the agenda.In this paper,a novel swaying test platform with folders is proposed.The advantage of this mechanism is its wide motive range,no parasitic motion,strong bearing capacity and impact resistance.In order to give full play to tis characteristics,it is necessary to analyze its kinematics,dynamics and related characteristics in detail.Firstly,the degree of freedom of the swaying test platform with folders is calculated based on the screw theory.The folding is very difficult for kinematics modeling of parallel robot,this paper carries out the calculation of Jacobian matrix of plane based on geometry principle and velocity projection on the hinge chain.The analytic solution of inverse kinematics is obtained in kinematics analysis.The numerical solution of forward kinematics of parallel mechanism is obtain by Newton iterative method.The workspace of the swaying test platform is drawn according to the forward kinematics,invers kinematics and leg length constraint.The multi-rigid body dynamic model of swaying test platform is established by Kane method,and the whole dynamic model of swaying test platform is constructed with the model of hydraulic power mechanism.Secondly,the 6 legs of the swaying test platform with folders are equivalent to 6 springs.The vibration equation of the system is established by the general stiffness matrix and the general mess matrix of the system.The natural frequencies and the natural modes of the system.The natural frequencies and the natural modes of the system are derived theoretically.The correctness of the natural frequency calculation is verified by comparing with the ADAMS simulation results.For the non-redundant variant mechanism of the original mechanism,the condition number of Jacobian matrix is calculated to find the singular configuration,and classify the singular configuration.The singular configuration of the swaying test platform with folders is analyzed by the manipulability.The reasons of singularity elimination of redundant outrigger are revealed.Finally,the PID controller in joint space control strategy is used to control the swaying test platform,and the control performance is satisfied by the dynamic pressure feedback correction.The internal force model is established based on inverse dynamic equation.Through the internal force coordinated control strategy,the internal force in each actuator is greatly reduced,and the effectiveness of internal force coordinated control is proved.The internal force in the ideal and non-ideal case are analyzed,and the reasons of the internal forces in the ideal case are explained.The impact force of parallel robot under actual working conditions is simulated and analyzed,and the stability of parallel robot under impact load is proved.