The 2-DOF linkage mechanism system is investigated in this paper. Based on the air-gap field of non-uniform airspace of motor caused by the vibration eccentricity of rotor, the electro- mechanical coupling relation in the real running state of motor is analyzed. And the electro- mechanical coupling nonlinear dynamic model of the system is established by the finite element method. The dynamic equation is the bases on which the subharmonic resonance properties of the system caused by self-excited inertial force effected by the actual operating frequency of the rotor of the controllable motor are analyzed by the multiple scales method. The first-order stationary solution is obtained under that condition. The work presented in the paper is benefit for further studies on the inner connections between dynamic characteristics and motors electromagnetism parameters of such mechanism system, a numerical example is presented.

A lateral-torsional coupled vibration model of the slewing mechanism of a hydraulic excavator is developed with consideration of the effect of lateral vibration and torsional vibration of sun gear and planetary gear on mesh displacement, the mesh stiffness of gear pairs, the bearing stiffness of the planetary and the coupling relationship of two stage planetary gear trains. The dynamic response of the slewing mechanism of a hydraulic excavator is obtained. Compared to the pure torsional vibration, the lateral-torsional vibration model is more reasonable.

Metamorphic mechanism would result in impact when it was changing from one configuration to the next. As a result, the internal impact force would bring about great vibration for the mechanism. What was more, it would make the mechanism be unstable. Therefore, the internal impact for metamorphic mechanism was expected to be analyzed. The controllable metamorphic palletizing robot mechanism was investigated in this paper. First of all, its kinetic characteristic was analyzed. In addition, the total momentum of the link which suffered impact was calculated. Furthermore, the impact force of the link was known. Finally, the relationship between the impact time when the mechanism was changing configuration and the momentum of the link was described through example study. The work of this paper provides some references for stability study of metamorphic mechanism.

The palletizing robot mechanism was investigated in this paper. The concepts of the metamorphic mechanism and controllable mechanism were introduced into the design of palletizing robot mechanism, a novel controllable metamorphic palletizing robot mechanism with geometric limit, which can achieve a variety of flexible action, was designed. The working space of output of the controllable metamorphic palletizing robot mechanism was obtained through simulation study, and the kinematics characteristics of the mechanism were analyzed. The work of this paper provides some references for the practical application of such kind of mechanism in the palletizing robot.