Master Thesis - Hochschule Bonn-Rhein-Sieg

2. Overview on human-robot Master Thesis Björn Ostermann page 14 of 126
2.3 Overview of the project at the BGIA
Prior to this master thesis two project reports have been created [77] [78], which have laid the
foundation of this thesis and their results are included in this report.
This chapter summarizes the complete framework project, consisting of both reports and this thesis.
The overall goal of the complete project is to develop a collaborative workspace, consisting of an
industrial jointed arm robot, a sensor system and a control system that allows a human operator to
work safely in close proximity of the robot.
In the R&D 1 report: “Development of a prototype of an autonomous motion control for assisting
industrial robots” [77] several approaches to this topic were evaluated (see chapter 2.2) and a solution
to the topic was developed.
At the beginning of the R&D 2 project the developed theoretical approach to the above mentioned
solution was discussed on the point of feasibility. An optimal tradeoff between functionality and
feasibility was found, which is briefly described in chapter 2.3.1, along with the different algorithms in
chapter 2.3.2 that are needed for the completion of the project in this master thesis.
The hard- and software, discussed in the R&D 1 report, on which the project is implemented, was
selected in the R&D 2. A description of this hard- and software, as well as its assembly in this master
thesis, can be found in chapter 3.
The main attention of this report is on the designed program that shows how the robot can be
controlled to evade dynamic objects in its working place. Additionally, in chapter 6.4, the performance
of the system is evaluated and compared to an optimal system.
2.3.1 Path planning approach
As described in the previous R&D 1 report [77], there are several modes of safe human-robot
collaboration that can be achieved. The easiest is to separate the human and the robot completely, thus
allowing no cooperation at all. The most difficult is to allow the human and the robot touching each
other, while still executing tasks. To collaborate with a human, robots have to sense their complete
environment and act accordingly, because safety, mainly of the human operator, is always the biggest
issue.
The approach described in the R&D 1 report has been designed to allow a high degree of collaboration
between human and robot, enabling the human to touch and interact with the robot at all times. This
approach not only puts high demands on the required hardware, using for example at least two high
tech 3D cameras, but also needs a lot of computational effort, which in turn puts high demands on the
processing capabilities of the logical unit.
Based on the knowledge, acquired in the first report, a practical approach was found. This approach is
a tradeoff between the functionality of the previously developed algorithm and the simplicity of a
fence. It was develop in the R&D 2 report [78] and can best be described as a flexible fence. Human