Numerical Imitation Simulation of Assembly Mechanism Dynamics

Abstract

Numerical simulation is widespread method to investigate machines and robotic mechanisms in different applications. Program complexes such as MATHLAB Simulink and similar ones are based on the assumption that mechanism kinematics can be described by kinematic scheme and it does not change on time interval of simulation. This is used to generate equations of dynamics automatically and then calculate the mechanism motion. Formulated assumption does not take place for numerous applications cause a set of contact points between mechanism parts is not permanent. This circumstance restricts application area of simulation method and accuracy of investigations. "Physical drives" are software systems for motion simulation of interacting bodies in real time. This restricts the complicity of dynamics model that are used in simulation. The paper describes the simulation method in which mechanism is represented as mechanical system of geometrical bodies. Their motion is defined by Lagrange virtual movement principle. Simulation algorithm generates equations automatically when all contact points between mechanism parts and with external environment are found. Simulation program was been used to investigate the motion of cylindrical shaft in assembly operation. It was been became all scenarios of shaft motion relatively hole. Each of them is defined by initial position of shaft and hole and also mechanical features of assembly device units or features of assembly manipulator servo control system. Simulation algorithm calculates assembly force, forces and moments are acted in mechanism and between mating surfaces. Developed simulation program can be used for choosing of constructive parameters and defining acceptable deviation in initial shaft position.