Non-probabilistic Reliability Analysis Of Flexible Manipulator With Clearance Considering Parameter Uncertainty

The flexible manipulator has the characteristics of light weight,large load,high flexibility,low energy consumption,and fast operation speed,and has a very wide range of application prospects.In the mechanical system,due to assembly manufacturing errors,design tolerances,friction,wear and thermal deform ation,the geometric parameters,material parameters,model parameters used in the modeling process,and the clearance dimensions of the kinematic pair in the mechanical system are uncertain,and the uncertain parameters are expressed in the form of interv al variables.These interval variables make the movement of the actual mechanism deviate from the ideal mechanism,reduce the movement accuracy and stability of the mechanical system,and then affect the reliability of the mechanical system.Different from traditional probabilistic reliability,non-probabilistic reliability has relatively low requirements for data,which is very suitable for studying the reliability of mechanical systems under the influence of interval variables.In this paper,it studies the non-probabilistic reliability of the rigid-flexible manipulator system with clearance under the influence of uncertain parameters in detail,and the contents are as following:Firstly,the clearance model is established by the collision force model and the state function,the deformation of the flexible manipulator is described by the hypothetical mode method,and the dynamic model of the rigid-flexible manipulator system with clearance is established by using the Lagrange equation.On this basis,considering the uncertainty of the system parameters,the uncertain parameters of the system are described as interval variables,and the uncertainty dynamics model of the rigid-flexible manipulator system is established.Using Chebyshev expansion function as interval algorithm,the process of solving the dynamic equation of rigid flexible manipulator system with interval variables by Chebyshev expansion function is established.Then,based on the non-probabilistic reliability modeling method,and considering the motion accuracy and motion stability of the flexible manipulator system,the state functions of four non-probabilistic reliability models are established respectively,and the corresponding non-probabilistic reliability indexes are established.Combined with Chebyshev interval algorithm,the uncertain dynamic model of rigid-flexible manipulator system is solved.The four model indicators are calculated and simulated respectively,and compared with the Monte Carlo method,the characteristics of the four models are analyzed.Furthermore,the geometric material parameters of the flexible arm,the clearance dimensions of the kinematic pair,and the clearance model parameters are analyzed as interval variables,and the end displacement and angular acceleration o f the flexible arm are simulated and analyzed under the two cases of single interval variables and mixed interval variables.On this basis,combined with non-probabilistic reliability theory,simulation analysis of the changes of non-probabilistic reliability indicators under the influence of different interval variables.Finally,using the definition of non-probabilistic reliability sensitivity,a nonprobabilistic reliability sensitivity analysis method is established to analyze the reliability of the flexible manipulator system,and the degree of influence of different interval parameters on the reliability of flexible manipulator system is analyzed in detail through simulation.So as to provide guidance for the reliability design of the mechanical system.