Analysis With Mechanical Properties Of Manipulator With Clearance Joint In Different Gravity Envirenment

With the development of modern machinery towards high speed and precision, the influence of clearance on mechanism motion has attracted much attention of home and abroad scholars. Aimed at the general phenomenon of joint with clearence in mechanism, take the manipulator with clearence joint, a series of key problems about the dynamic and static mechanics are studied deeply, including the followings:Firstly, the various clearence of the mechanism joint are described in detail, three kinds of clearence joints model used in the present research were compared and analyzed, and the two-state model of the "contact-separation" is chosen to be the motion model in this paper. The mathematical model is carried out based on the current multibody system theory when in the study of dynamic problems. Compared with the analysis among the existing multibody dynamics modeling theory, the Newton-Euler method is chosen to set up dynamics equation of the manipulator.Secondly, adopt the nonlinear spring-damp model to simulate the issue of the contact force around joint. The established dynamics equation shows the feature of nonlinear and rigidity because of considering joint clearance. By comparing the existing methods of solving differential equation, Gear method is chosen to solve dynamic equations of manipulator with clearance joint. When the driving force of manipulator of single clearance joint is given, the curves of contact force and the central trajectory of shaft are obtained in different gravity environment. And the curves of the contact force and the central trajectory of shaft in different clearance, different contact stiffness, different speed are also obtained when manipulator rotate constantly. and the simulation curves mentioned above are deeply discussed. On the basis of the analysis of manipulator movement features with single clearance joint, the movement features of manipulator with double clearance joints also have been deeply disscussed.Finally, based on the ANSYS software, the static analysis and the modal analysis of both the manipulator with ideal double joints and double clearance joints were carried on. The deformation, strain and stress curves of the two kinds of manipulators are obtained through the static analysis. The vibration modal figure of the two kinds of manipulators are obtained through the model analysis.