Solving Inverse Kinematics Problem of Discretely Actuated Hyper-redundant Manipulators using Multi-module Searching Method

The manipulators whose degrees of freedom are high are called “hyper-redundant manipulators”. High degrees of freedom make them dexterous and able to avoid the obstacles. Here, the term hyper-redundant manipulator is used for the manipulators which are produced by cascading the serial or parallel mechanisms on top of each other, as modules. The discrete actuators can have a few stable states. These actuators usually need no feedback in their control. This causes them to have a simpler control, to be cheaper, more precise, and to improve the repeatability. So far, several methods have been proposed to solve inverse kinematics problem of discretely actuated hyper-redundant manipulators. The two-by-two searching method is better than the other methods in terms of CPU-time and error. In this paper, the mentioned method is generalized by choosing an arbitrary number of modules as pending modules in each step of searching, instead of necessary two. Also, the effect of the number of pending modules on CPU-time and error is investigated. For this purpose, two planar and spatial manipulators are introduced to define the inverse kinematics problems and then the results are analyzed and compared.