Dynamic Optimization And Control Of 2R1T Parallel Spindle Head

With the development of industry,machining and manufacturing in aviation field has attracted more and more attention.Five-axis machine tool is widely used in the machining of aviation field.For the reconfigurable redundant drive 2R1 T parallel spindle head,due to the singularity in its workspace,and under the singular configuration,the internal force distribution of the driving force of the pseudo-inverse solution of dynamics has a mutation.In this paper,the reconfigurable redundant drive 2R1 T parallel spindle head is taken as the research object.By establishing the dynamics model of the mechanism,the dynamic driving force under the singular configuration is optimized,and the control mode of the drive joint under the motion path is determined by the motion/force performance graph.The error modeling of the parallel spindle head is analyzed.First of all,in order to study the optimal distribution of the redundant driving force of the parallel spindle head,a dynamic model of the parallel spindle head needs to be established.In this paper,the relationship between the velocity acceleration of the joint and the branch and the velocity acceleration of the parallel spindle head is obtained by means of vector closed-loop derivation,and combined with the principle of virtual work,a system dynamic model with the end of the parallel spindle head as the generalized coordinate system is established.Secondly,on the optimization of force distribution and control strategy of redundant driving force of parallel spindle head,the condition number of Jacobian matrix of force was taken as the evaluation index,and some driving forces were interpolated by cubic polynomial to eliminate force abrupt change,and the curves of other driving forces were solved quadratic by dynamic balance equation,so as to eliminate the problem of force abrupt change of parallel spindle head through singular configuration.Based on the force transfer performance map,the global singular configuration distribution was analyzed,and the force-position control was assigned to the driving joint.Then,the error model of the parallel spindle head was established through the vector closed-loop first-order perturbation,and the sensitivity of the end error of the parallel spindle head to the error source was analyzed to provide guidance for the machining,manufacturing and assembly of the machine tool and the control of the drive joint.The error source was identified and simulated by the quantum particle swarm optimization algorithm.Finally,the control of the parallel spindle head is simulated,and the position control under the non-redundant drive,the force-bit mixed control under the non-singular path and the force-bit mixed control under the singular path are simulated respectively,which verifies the feasibility of the theory.