The Trajectory Planning Of The Silk Laying Robot And The Analysis Of Its End Vibration Characteristics

The Automated Fiber Placement(AFP)robot have been widely used in the placing variable stiffness composite laminates.The fiber placing device is an end effector of the AFP robot,which has the characteristics of large process size,large mass,and complicated system.However,in practical engineering applications,the fiber placing device will generate vibration,as a result,the track accuracy is declined and the positioning accuracy is inaccurate of the AFP robot.In the working process of the AFP robot,How to control the accuracy of the placement track and the stability of the device has become a hot issue in the application field of AFP robots.Therefore,it is great significance to carry out trajectory planning and vibration characteristics analysis of the AFP robot.The kinematic model was established,which is based on the structural parameters of the AFP robot.The correct kinematic inverse solution is obtained on the basis of the industrial robot structural characteristics and the space requirements,which lays the foundation for the next trajectory planning.With the secondary development platform provided by SolidWorks,the offline simulation environment of the AFP robot was completed,which provided a platform for verifying the rationality and correctness of the planned trajectory.The mechanical requirements of the automatic fibre placing equipment and the physical property constraints of the narrow band of the carbon fiber prepreg are taken into consideration.Variable stiffness lays the baseline trajectory,which is compliant with the maximum stress direction of the laminate and has C2 smoothing properties.The method of constructing the trajectory is based on the finite element stress analysis,and the maximum principal stress point within the allowable range of the diagonal deviation on the diagonal is used to reverse the cubic non-uniform B-spline curve.The B spline curvature formula is used to verify the curvature variation range of the baseline and whether the variation range is within the required range.The placement reference trajectory is translated by the control point translation method,and the next adjacent trajectory is proposed.The golden section method is used to search for andcalculated the shortest distance between adjacent trajectories,and based on the requirements of the overlap pressing process,the trajectory is corrected by using control point translation.Cycle this way until the trajectory planning of the entire laminate is completed.The vibration characteristics of the AFP robot were studied experimentally,the first-order and second-order frequencies of the AFP device were determined at different pose points under the shutdown and working states.The xy coordinate range of the workpiece placement is used as the optimization parameter,If the first order frequency is constant,the second order natural frequency of the placement device is the objective function,the actual workspace of the robot and the specific size of the workpiece are the constraints,the vibration frequency at the test point is used to optimize the placement of the workpiece.Finally,The purpose of reducing the vibration of the fiber placing device and improving the position accuracy of the fiber placing trajectory is achieved.Based on the above work,the efficiency of placing can be improved as much as possible on the premise of satisfying the placing technology and quality of the AFP robot.Based on the maximum principal stress,the cubic non-uniform B-spline curve variable stiffness placement trajectory planning of laminated plate is realized,which meets the requirements of stable,smooth and fast completion of placement tasks of the wire laying robot.