Unified Theoretical Model And Type Synthesis Method For Decoupling Of Generalized Hybrid Mechanism

Output freedom of the decoupled mechanism can be realized separately through corresponding driving input.The decoupled mechanism has good kinematic performance,control characteristics and maneuverability.The decoupled mechanism is the first choice of all kinds of mechanical equipments,and attracts much attention of scholars and industries.With the expansion of decoupled mechanism configuration,the unified theoretical model is the basic theoretical content for defining the decoupled mechanism.The configuration of parallel decoupled mechanism and hybrid decoupled mechanism are expanded based on decoupled kinematic chain,which provide an important theoretical base for synthesizing various kinds of high-tip decoupled mechanical equipments.Taking the generalized hybrid mechanism(including series mechanism,parallel mechanism,hybrid mechanism and module hybrid mechanism)as the object,this paper mainly carried out the following research work.(1)The unified theoretical model of the generalized hybrid mechanism is established.The decoupling mathematical description of the generalized hybrid mechanism is presented and classified based on the matrix theory and differential geometry.Based on the unified mode of functional algebra,the joint space and the operation space of the mechanism with the driving information space and the motion pattern space of the mechanism are uniformly described as the mapping relations of the topological space.The topological relation mapping model for decoupling of the generalized hybrid mechanism is established,which provides a unified theoretical basis for the configuration decision of the generalized hybrid mechanism.(2)The synthesis procedure of the decoupling of series limb is established.The axis migration principle of plane axes,spatial axes and concurrent axes are analyzed according to the rules of movement synthesis.The canonical decouple synthesis principle and realized conditions of limb are provided.The limb configuration relationship is established according to output moving characteristics of parallel mechanism.Three canonical decoupled limbs and complex kinematics are proveded.The synthesis procedure of limb decoupled is proposed based on morphological algorithm.(3)Parallel decoupled mechanism is synthesized based on screw theory and Lie groups.The limbs,which satisfy the requirements of movement output,are synthesized using Lie group theory.The limb movement screw can be obtained based on the reciprocal relationship of movement screw and constraint screw of the mechanism and the constraint screw relationship between the mechanism and the limb.The canonical decoupling limbs can be selected from the limbs synthesized using Lie group theory.A parallel decoupled mechanism is constructed using decoupled limbs with different degrees of freedom to connect the moving platform and the base.Taking 2T1 R parallel mechanism as an example,the decoupling configuration synthesis is carried out.(4)The parallel decoupled mechanism is synthesized based on redundant constraint.The moving characteristics kinematic chain is synthesized based on the output moving characteristics.The other kinematic chains are synthesized based on redundant constraint subset of the moving characteristics kinematic chain.The decoupled configurations are proposed by connecting the moving platform and the base with different kinematic chains.The driving pairs are selected based on output moving requirements.Taking 2R1 T parallel mechanism as an example,the decoupling configuration synthesis is carried out.(5)Decoupled hybrid mechanism is synthesized based on generalized basic kinematic chain.Based on the characteristics of canonical movememt,a generalized basic kinematic chain which is consisted of the moving platform of parallel translatioal decoupled mechanism and the canonical rotational kinematic pairs is established through separation of position and orientation.Through integrating the decoupling of driving chains between canonical translation and canonical rotation,the decoupling type synthesis of the hybrid mechanism is proposed.Taking 3T2 R hybrid mechanism as an example,the decoupling type synthesis is carried out.