Research On Analysis And Evaluation Of Reachability Based On Maintainability Design

The reachability can improve the efficiency of maintenance, and reduce the life cycle cost of the mechanical product. Reachability is the inner quality characteristic of product, it should be considered well at the stage of design.By analyzing the different factors which have effect on reachability, three criterions for evaluation of reachability are put forward i.e. visibility, entity reachability and operating space. The synthetic evaluation model of maintenance reachability is built. To evaluate the visibility, firstly, construct the visible area of maintenance part which is just the feasible space of the eyes' position. Then according to the field of human being's physiological view, the visual cone is constructed. Finally, the visibility of maintenance part is evaluated according to its position in the filed of the visual cone. To evaluate the entity reachability, firstly, search the best posture of the upper arm by particle swarm optimization. Then based on the kinematics model of human being's arm, compute the angles of forearm by D-H method. Finally, according to the human comfort of the best posture of arms, the entity reachability is evaluated. The evaluation of operating space includes two sub problems i.e. tool's motion space and arm's motion space. For one thing, the tool's motion space is evaluated by simulating its maintenance movement and real-time collision detecting method. For another, the arm's space is primarily analyzed by measure method. Then, by sample on the hand's motion track, convert the problem of area's motion space to the problem of entity reachability. Finally, according to the satisfaction degree of space, the operating space is evaluated.In the end, the fastener in a main wheel box in tank as an example is evaluated by the method of maintenance reachability. The result is reasonable and it is useful to maintenance design.