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Ch20-I044963.fm Page 93 Tuesday, August 1, 2006 5:47 PM
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ANALYZING AND EVALUATING ROBOT MOTION ALGORITHM
FOR SWEEPING TASK
Yuki Saito, Masanori Ezawa, Yusuke Fukumoto, Hiroyuki Ogata, and Akira Torige

Department of Mechanical Engineering, Seikei University
3-3-1 Kichijojikitamachi, Musashino-shi, Tokyo, Japan

ABSTRACT
Recently, sweeping robots, such as cleaning robots for home use, have been actively developed. Most
of these robots generate their motion by reactive algorithm with easy sensors mounted. However, with
these algorithms, the sweeping task would be done uneven to the sweepable areas. So there are still
rooms for developing a more efficient algorithm. To develop an efficient algorithm, evaluation method
is in need. However, the methodology to evaluate the efficiency of state informed algorithm has not
yet established. Cleaning robots do not always clean the same environment, so the difficulty of this
research is that consideration of various kinds of environments is in need. We developed sweeping
robot simulator to analyze the existing sweeping algorithms, and reveal their inefficient features to
improve the existing algorithms. The algorithms that commercial robot cleaners install were analyzed,
and those efficiencies were estimated.

KEYWORDS
sweeping task, motion planning, robot cleaner, planning-based method, reactive method

I. INTRODUCTION
Generating motion is important for the robots over doing some kind of task. Especially, generating
motion to cover certain area utilizing the size of the robot is used to realize robotic tasks such as
sweeping floors [1].
The method of generating sweeping task motion can be roughly classified into two groups. One is
called planning-based method and the other is called reactive method. Planning-based method plans
the sweeping task motion from the information of the environment given beforehand to carry it out.
This method can consider optimization of the amount of the task of robots. Reactive method generates
task motion on the fly based on information that was gained by sensors. It is often installed on the
robots that are on sale or under development. Base of those robots' motion is generated by the
combination of moving forward and reflecting in random as it collides. Here, we will name this
motion, air-hockey motion.
Sweeping robot use can be classified into two; for domestic and for affair. To consider about the latter,
because owner uses it as a substitute for an employee, high quality task performance will be required.
So the robot will be equipped with lots of sensors and functions, though it will cost. The environment
could be regarded as static, and also, the algorithm to sweep vast areas is in need. From this point of
view, planning-based approach is suitable to it, because planning-based approach often assumes that
the environment is static, and can generate effective motion to sweep a large area.
The specification on demand of robot cleaners between for domestic and for affair completely differs.
To consider about the sweeping robot for domestic, the operation is asked to be simple, thus