Hindawi Publishing Corporation
Journal of Robotics
Volume 2011, Article ID 549489, 9 pages
doi:10.1155/2011/549489
Research Article
Optimal Search Strategy of Robotic Assembly Based on
Neural Vibration Learning
Lejla Banjanovic-Mehmedovic,
1
Senad Karic,
2
and Fahrudin Mehmedovic
3
1
Faculty of Electrical Engineering, University of Tuzla, 75000 Tuzla, Bosnia and Herzegovina
2
H&H Inc., 75000 Tuzla, Bosnia and Herzegovina
3
ABB, 71000 Sarajevo, Bosnia and Herzegovina
Correspondence should be addressed to Lejla Banjanovic-Mehmedovic, lejla.mehmedovic@untz.ba
Received 17 July 2011; Accepted 8 November 2011
Academic Editor: Ivo Bukovsky
Copyright © 2011 Lejla Banjanovic-Mehmedovic et al. This is an open access article distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
This paper presents implementation of optimal search strategy (OSS) in verification of assembly process based on neural vibration
learning. The application problem is the complex robot assembly of miniature parts in the example of mating the gears of one
multistage planetary speed reducer. Assembly of tube over the planetary gears was noticed as the most difficult problem of overall
assembly. The favourable influence of vibration and rotation movement on compensation of tolerance was also observed. With
the proposed neural-network-based learning algorithm, it is possible to find extended scope of vibration state parameter. Using
optimal search strategy based on minimal distance path between vibration parameter stage sets (amplitude and frequencies of
robots gripe vibration) and recovery parameter algorithm, we can improve the robot assembly behaviour, that is, allow the
fastest possible way of mating. We have verified by using simulation programs that search strategy is suitable for the situation
of unexpected events due to uncertainties.
1. Introduction
The planning is a key ability of intelligent systems, increas-
ing their autonomy, reliabilities, efficiently and flexibility
through the construction of sequences of actions to achieve
their goals [1]. In artificial intelligence, planning originally
meant a search for a sequence of logical operators or actions
that transform an initial world state into a desired goal
state. Robot motion planning usually ignores dynamics and
considers other aspects, such as uncertainties, differential
constraints, modeling uncertainties, and optimality. The
robotic assembly, wheelchair navigation, sewer inspection
robot, autonomous driving system in urban and off-road
environments, and machine’s task planning for the robotic
system all are examples of autonomous systems, which solve
path planning/replanning problems [2, 3].
Dynamic replanning is necessary because at any time
during execution of its tasks the robot might unexpect-
edly run into problems [2]. The typical approach used for
replanning is repair plans, which are prepared in advance and
invoked to deal with specific exceptions during execution.
This class of approaches may work well in relatively static and
predictable environment. In more dynamic and uncertain
environment where it is hard to anticipate possible excep-
tions, the replanning generates a (partially) new plan in case
when one or more actions have problems during execution
[4].
Very interesting area of research is using planning
strategies in robot assembly. The example components can
be assembled faster, gentle, and more reliably using the
intelligent techniques. In order to create robot behaviours
that are similarly intelligent, we seek inspiration from
human strategies date [5]. The working theory is that
the human accomplishes an assembly in phases, with a
defined behaviour and a subgoal in each phase. The human
changes behaviours according to events that occur during the
assembly, and the behaviour is consistent between the events.
The human’s strategy is similar to a discrete event system in
that the human progresses through a series of behavioural
states separated by recognizable physical events.