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

With the development of modern high technology, position precision, the reliability of the mechanism of aerospace precision, control, long life and environment adaptability requirements continue to increase. As a theoretical tool to measure and predict the above performance, the research of system dynamics has a very important position in the design and control of Aerospace Precision mechanism. Joint clearance and lubrication are the key factors that affect the dynamic characteristics of the mechanical system. Therefore, scholars at home and abroad pay more and more attention to the influence of joint clearance and lubrication on the dynamic characteristics of Aerospace Precision mechanism. However, according to public information, the current research in this field is mainly confined to the effect of joint clearance on the dynamic characteristics of the mechanism, while the impact of joint lubrication is less. Therefore, in this paper, under the premise of joint clearance and lubrication, the dynamic characteristics of multi body mechanism are studied and analyzed, including the following:In order to make the dynamic model of multi-body system and the actual situation of the work is close contact, two state models of the "contact separation" as the rotating hinge mechanism. Based on this model, respectively established the multi-body system in the working process of the collision force model, friction model and Jiao Runhua model, and by using the Lagrange multiplier method of the agency’s kinetic equation.For bodies in multibody single revolute joint. In this paper, the nonlinear spring damping model to describe the gaps between the hinge contact process, by Pinkus-Sternlicht model to describe the effect of joint lubrication on the process of mechanism motion. Based on the above model, considering joint clearance and lubrication conditions using gear method is used to solve the dynamics equations of the mechanism, and comprises a pin shaft and sleeve of the collision force, required to maintain a constant speed driving torque and a pin shaft center trajectory, the dynamic characteristic dynamic parameters of main research. Under the joint gap, by considering the joint lubrication is to study the effect of joint lubrication, the dynamic characteristics of the institutions; and on this basis, and further study of the gap size, input speed, lubricant viscosity and friction coefficient on the dynamical characteristics.In consideration of the joint clearance and lubrication conditions, using ADAMS software on a single rotating hinge for the dynamics simulation and the theoretical calculation of the dynamic characteristics and simulation to obtain the dynamic characteristics are compared and analyzed. The results show that the two are basically consistent, which verifies the validity and accuracy of the lubrication theory model.