| In modern manufacturing industry,the robot is more and more widely used.With the accelerating of the manufacturing automation process,robot must be endowed the more flexible way of working and wider applications.Because the traditional robot configurations were fixed after the completion of the design,there is poor flexibility of them so that they can be applied to the task as its design goal or other similar work merely.It not only needs more cost that designing a special robot system according to the different work but also has long development cycle.It cannot meet the increasing change of the working environment.In order to overcome these restrictions of traditional robots,reconfigurable modular robot was invented and used to the field of industrial manufacturing quickly.In aerospace,automobile and other fields,the elastic sheets and flexible slightness beams are always need to be moved and assembled by robot.In the process of the robot operating flexible load,it will inevitably occur vibration,which greatly reduces the robot's operating accuracy.Based on the research background,this paper has carried out the dynamic modeling of the flexible load of the reconfigurable robot,and the research on the vibration suppression of the robot trajectory planning is carried out on the basis of this research.Robot handling flexible load is a nonlinear and strong coupling complex system,and the reconfigurable robot operating flexible load modeling not only has flexible load modeling system of the difficulties of traditional robot operation,also need to consider the effects on the model of the robot configuration changes.Firstly,this paper puts forward a layer sequence array and use it to describe the mathematical configuration of the reconfigurable robot,and combined with exponential product formula to achieve the automatic generation of reconfigurable robot kinematics;secondly the deformation spinor and modal coordinates are combined to describe the deformation of flexible load and supported at any point on its fixed coordinate transformation relation,by robot end clamps and flexible load between relations determine the load at any point in the reference coordinate position and velocity.Flexible load dynamics modeling of reconfigurable robot is the basis of the research of load vibration.In this paper,the dynamic equation of the system is established by using Lagrange equation.Firstly,on the basis of kinematics studied the kinetic and potential energy of the robot system and will be brought to the Lagrange equation,then the dynamics model of the robot is obtained;Secondly,on flexible load analysis for the in the reference coordinate system of kinetic energy and potential energy,and derive the dynamic equation;finally,the robot end clamps and flexible load between the relationship of force to establish the dynamics model of the whole system.The robot can generate vibration during the operation of flexible load,which affected the end operation accuracy.Aiming at which problem,the trajectory planning method based on particle swarm optimization algorithm is proposed to restrain the vibration of the load end.Firstly,establishing the relationship between vibration modal coordinates and robot joint variables load.Secondly using piecewise polynomial interpolation methods of joint variables planning,indirectly established the relationship between the objective optimization(load end vibration)and the optimized parameters(polynomial time).Finally,the vibration suppression problem will be converted into the time interpolation parameter optimization problem,and the particle swarm algorithm is used to complete the optimization process.Because of the formulas are general formulas derived by the unknown configuration,this paper finally to a three degree of freedom can be reconfigurable modular robot operation flexible bar system as a model to carry on the simulation computation.The simulation results show the effectiveness of the modeling method and the trajectory planning method. |
PDF Full Text Request