Research On Innovative Design Method And Configuration Synthesis Of Variable Degree Of Freedom Mechanism

The variable degree of freedom mechanism is a special mechanism that can change the constraint form of the motion pair and the rod during its own movement,thereby completing different forms of movement.It can start from the needs of movement,and achieve the functions of safety protection,sequential action and balanced force that conventional mechanisms require multiple complex designs to complete.The advancement and development of variable-degree-of-freedom mechanisms has enriched the theoretical and applied research of modern mechanism.By analyzing the traditional formation methods of variable-degree-of-freedom mechanisms and their differences with other similar institutions,a systematic and innovative design method is proposed.First,the design task is decomposed into different stages of motion requirements;secondly,conventional mechanisms of each sub-stage before and after the change in degrees of freedom are designed according to the motion requirements;finally,sub-stage mechanisms are merged into the variable degree of freedom mechanism.Through the constraints of the moving components in different stages to achieve the transformation of degrees of freedom,complete the design task.This method aims at the two basic design principles of "constraint" and "variable degree of freedom" of variable-degree-of-freedom mechanisms.It uses conventional mechanisms to solve the design problems of special mechanisms,and provides a new idea for the innovative design of variable-degree-of-freedom mechanisms.In the design process of the sub-stage mechanism,the evolution theory is introduced to realize the innovative design of the structural form.The entire evolution process sets a constraint function according to the design task and adds directional discrimination criteria to enable the mechanism to achieve directional evolution in evolution.The entire evolutionary design process has expanded the mechanism form around the movement requirements,and the design process has also been simplified.Aiming at the problem that the topological graph and the adjacency matrix cannot represent the transitions between the various degrees of freedom of the mechanism in the same model,the sub-stage mechanisms are merged and expressed on the tree graph model.The special level of the tree graph model is used.Structure,the different moving parts in the model are packaged and constrained,and the degrees of freedom can be converted,and the positional relationship between the moving parts and the overall mechanism at each stage can be clearly understood.Finally,based on the design method,a variable-degree-of-freedom mechanism intelligent design prototype system is constructed.The system includes four modules: design knowledge base,demand analysis,evolutionary calculation,and evaluation and screening.The transmission mechanism design of the picking system of the high-cluster blueberry picking machine is taken as an example to verify the feasibility and rationality of the prototype system,which enriches the application of intelligent design in the mechanism.