Tvarově měnitelné segmenty nosných prvků robotických systémů

Abstract

Robotic systems in today's manufacturing processes have fixed connecting segments between joints. These elements are very often made from commonly available semi-finished products such as tubes, rods, castings, etc. These elements are mostly straight and their shape and dimensions define the working envelope of the robotic system. A robotic system with these elements has a rigid kinematic structure. This brings advantages with respect to the requirements such as, good repeatability of positioning, load capacity, etc. The disadvantage is that these systems are not flexible and mostly serve a single purpose. In case of a change in the work task, a situation may arise where the existing kinematics of the system is not sufficient or optimal. One way to solve this problem is to reconfigure the robotic system and thus the manipulator workspace by increasing the degree of freedom (DoF) by adding a module. Increasingly, systems are emerging that do not increase the number of degrees of freedom, but do change the shape of the connecting segments. With a suitable change in the shape of the connecting segment, the system can achieve a change in the working envelope that is sufficient and optimal for the new task. The present thesis deals with the topic of shape changing segments as supporting elements of robotic systems. The introductory part of this thesis explores the possibilities of increasing flexibility by adding modules to existing structures. The types of modules and the possibilities of connecting them are described. Furthermore, the introduction of the work deals with systems with variable stiffness and shape changing capabilities. The principles of how systems achieve variation in stiffness and thus shape are described. Then, the objectives of the thesis are stated, which are based on a survey of the current state of the art of shape changeable segments. The actual part of the thesis is divided into subchapters, according to the individual defined objectives of the thesis. The thesis describes the determination of the bending possibility of a shape-changing segment and the method of defining its length. The possibilities of robotic systems with curved elements are presented by simulation. Furthermore, an experimental segment with variable stiffness based on the use of a low melting point material is presented. Three experiments were performed on the experimental segment to determine its mechanical parameters. Subsequently, the paper discusses the necessary variation of the low melting temperature material and the method of changing its stiffness. In the penultimate and last chapter, the results are summarized and the contributions to science, practice and recommendations for further research are defined.