Abstract: In order to ensure the high precision and stability of fast docking and separation of two precision measuring instruments,a fast docking mechanism with high precision repeated positioning is designed.The three-point support method is adopted to ensure that the two instruments that need to be connected have high repeated positioning accuracy and constant error.The butt locking mechanism is formed by locking chuck and adjusting button,which realizes the high reliability and stability of the six degrees of freedom locking of two instruments,and realizes the rapidity of butt and separation.The installation limit function is designed to ensure the repeatability of the installation position.The principle of butt joint mechanism and the uncertainty factor of repeated positioning error is analyzed in brief.Finally,the design test is carried out to test the repeatable positioning accuracy of the two precision measuring instruments.The test results show that the fast docking mechanism has high repeatable positioning accuracy,which proves the design is reasonable.

Key words: Repeated positioning, Three-point support, Fast docking, Locking