Papers by Author: Jing Feng He

Abstract: In this study, we analyze the influence of passive joint viscous friction on modal space decoupling for a class of symmetric spatial parallel mechanisms. The Jacobian matrix relating the platform movements to each passive joint velocity is first gained by vector analysis and the passive joint damping matrix is then derived by applying the Kane method. Next, an analytic formula index measuring the damping non-proportionality is proposed using classical modal analysis of dynamic equations in task space. Based on the index, a new optimal design method is found which establishes the kinematics parameters for minimizing the non-proportional part of damping and achieves optimal fault tolerance for modal space decoupling. To illustrate the effectiveness of the theory, the new method was used to redesign two configurations of an actual group manipulator.

Abstract: On the basis of introducing the latest research status of processing methods of waste printed circuit boards, the physical mechanism of eddy current separation was explained, and the component configuration of eddy current separator was described. A series of single-factor and orthogonal experiments were carried out to prove the separation effect of multiple metals with eddy current separator. The result indicates that the separation efficiency of above 92.0% and concentrate grade of above 95.0% can be obtained in the recycling of aluminum and brass with the delivery rate of 20~40%, rotate speed of rotor of 5~15Hz and belt speed of 7~9Hz.

Abstract: The reutilization of waste Printed Circuit Boards (PCB) is a focused topic in the field of environment protection and resource recycling, and the crushing is the crucial process for recycling waste PCB. A hamper impacting crusher was used to achieve metals crushing liberation from non-metals, the liberation mechanism of PCB can be explained by dispersion liberation accompanied disengaging liberation. The Rosin-Rammler distribution model of crushed PCB particle was put forward. The evaluation indexes show that Rosin-Rammler function can accurately describe size distribution of PCB particles because the convergence property R2 is 0.99694 and fitting error E is 4.80658. The selective crushing is appearance with metals concentrated in coarser fraction and non-metals in finer size during comminution processing. The impact crushing is an effective method to metals liberation of PCB particles.