Inverse kinematics analysis for incompletely restrained parallel wire mechanisms

This paper discusses parallel wire mechanisms where an end-effector of the mechanism is suspended by multiple wires. This mechanism enables not only three dimensional positioning but also three dimensional orientating of the end-effector, unlike typical wire suspension type mechanism such as overhead crane. To discuss the parallel wire mechanism, two forms of basic dynamic equations are presented. Then dynamical properties of the mechanism is described based on the basic equations. This paper mainly issues an inverse kinematics problem for general incompletely restrained type parallel wire mechanism. To distinguish some parallel wire mechanisms including the incompletely restrained type, the paper first defines constraint states of the end-effector, then parallel wire mechanisms are classified into three categories based on the definition. Each characteristic of the mechanism corresponding to the categories is described. Especially, incompletely restrained type parallel wire mechanism is mainly discussed in the view point of inverse kinematics problem. After arguing a general solution for the inverse kinematics problem of the incompletely restrained type parallel wire mechanism, an actual mechanism of the incompletely restrained type mechanism is presented and the inverse kinematics problem for this mechanism is analyzed.