Research On The Compliant Assembly Force Control Of Large-diameter Precision Parts

In the area of aerospace,automobile manufacturing,ship and so on,the precise assembly of large scale components is an important requirements.At present,there are few theoretical researches and experimental verification researches.With the strategic deployment of artificial intelligence in the new and old energy conversion,the range of assembly precision requirement is covered from meters to millimeters.As a consequence,the span of assembly operation space is increasing.The precise positioning of assembly position and the detection of contact force between precision components and external environment has become an important part of automatic assembly of large scale precision components during assembly process.In this paper,the technical problems of assembly force control for automatic assembly process of large scale precision components are studied.A set of active compliant assembly control system is designed for each contact state during the assembly process.The main contents and contributions of this paper are as follows:(1)Hand-eye calibration is done in the hole searching stage through deep camera during the peg-in-hole assembly process.The offline modeling of CAD model and the feature extraction of the peg-in hole edge is used to roughly located the position of the hole.The central axis of the peg is basically parallel to the central axis of the hole by the path planning of the robot motion.(2)The six-dimension force sensor is installed at the end of the robot flange to analysis force of different load assembly.A method gravity compensation and load system error calibration is put forward to accurately detect the actual contact force for disturbance of the external environment to the sensor's force feedback information.(3)The contact state of peg and hole and the contact force in different state is analyzed.Under the foundation of the algorithm in every contact state,the method of active compliant automatic assembly based on controlstrategy of force/position coupling is proposed.(4)Design a human-machine interaction interface,which includes monitoring state of force sensor and a message reminder window.Therefore,the interface is conducive to freely control for developers and operators and avoid damage to components.The assembly system contains visual positioning,force feedback and integrated control functions.The validity of the algorithm and feasibility of the active compliant assembly force control system of large scale precision components is verified based on control strategy of force/position coupling.The research results provides valuable experience and technology for automatic assembly in the manufacturing area of the artificial intelligence our country in the field of automatic assembly.