Geometric Analysis And Palm Synthesis Of The Spherical Five-bar Metamorphic Robotic Hand

This dissertation describes a novel robotic hand with a metamorphic palm, which is different from the traditional structure of a robotic hand. Based on analysis of the grasping operation and workspace of the robotic hand, a new approach of synthesis for spherical five-bar metamorphic palm is presented in the dissertation.At first, the kinematics model of a 2-DOF spherical 5R parallel mechanism is established. This model is discussed through displacement matrix method in details. The finger-operation plane and the workspace triangle are introduced to study the capability of the metamorphic palm.Secondly, the question for forming a spherical five-bar metamorphic palm is broken down into two relatively independent sub-questions. The first one is to create an open loop of three spherical links, on which the three fingers can achieve a maximum workspace. Its mathematical model is nonlinear and non-differential with multiple constraints. The problem is resolved by genetic algorithm followed by BFGS's method. The second one is to search approximate character points on moving spherical link with designed workspace and to then generate the metamorphic palm, whose mathematic model is also nonlinear and non-differential, constrained by many conditions. This is a kind of special non-differential max-mini optimal problem with inequality constraints. By the method of Saddle-point Programming and maximum entropy, the problem can be transformed into a differential optimal problem with single objective. Generally an optimal result depends on the initial point. In this dissertation, a series of good initial points is produced automatically by genetic algorithm.Finally, synthesis results are given to illustrate the effectiveness of the approach. 3D CAD modeling is provided to show the designed poses of the robotic hand.