Intelligent Algorithms Solve Differential-algebraic Equations Of Multi-body System Dynamics

With the rapid development of computer technology,the research of multi-body system dynamics has been widely used in aerospace,vehicle machinery,robotics,military and other fields.The design and optimization of complex mechanical system need dynamic analysis of multi-body system dynamics simulation,which urgently needs efficient and stable modeling method and numerical solution method to solve the dynamic equation of multi-body system.In this paper,the intelligent optimization method is studied to solve the differential algebraic equations of multibody system dynamics.Firstly,the differential algebraic equation of index 3 can be obtained by modeling the multibody system.Then,the generalized coordinates and generalized velocities are interpolated by Lagrange,and the problem of solving differential algebraic equations can be transformed into the problem of solving optimization by combining the method of variable reduction and Gauss numerical integration.The traditional optimization method is very difficult to solve the nonlinear complex space optimization problem.Intelligent optimization method is an effective method to solve this kind of optimization problem.Particle swarm optimization(PSO)which simulates bird swarm foraging,firefly which simulates firefly swarm activity and genetic algorithm which simulates biological genetic evolution theory are several typical intelligent optimization methods,which have the characteristics of simple algorithm,no need of derivative information and adapt to complex space.In this paper,the algorithm idea of these three methods is introduced in detail,and the algorithm is designed to solve the differential algebraic equation.The effectiveness of particle swarm optimization(PSO),firefly algorithm and genetic algorithm in solving the dynamic equations is verified by the multi-body system simulation experiment of planar double link manipulator.In order to reduce the difficulty of optimization,the variable merging method is used.The experimental results show that this method not only keeps the constraints but also ensures the energy accuracy,and further shows that the intelligent optimization algorithm has a good application prospect in solving multi-body dynamics problems.