|
INTROUCTION to Snake Robot
In the past two decades it
is estimated that disasters are responsible for about 3 million deaths worldwide,
800million people adversely affected, and property damage exceeding US$50 billion.
The recent earthquake in Turkey in November of 1999 left 700 dead and 5000 injured.
Many of these deaths were from structural collapse as buildings fell down onto
people. Urban Search and Rescue involves the location, rescue (extrication), and
initial medical stabilization of victims trapped in confined spaces. Voids formed
when a buildings collapse is one instance of a confined space. Urban Search and
Rescue may be needed for a variety of situations, including earthquakes, hurricanes,
tornadoes floods, fires, terrorist activities, and hazardous materials (hazmat)
accidents. Currently, a typical search and rescue team is composed of about ten
people, including canine handlers and dogs, a paramedic, a structural engineer,
and various specialists in handling special equipment to find and extract a victim.
Current state of the art search equipment includes search cameras and listening
devices. Search cameras are usually video cameras mounted on some device like
a pole that can be inserted into gaps and holes to look for signs of people. Often
a hole is bored into the obstructing walls if a void is suspected to exist on
the other side. Thermal imaging is also used. This is especially useful in finding
warm bodies that have been coated with dust and debris effectively camouflaging
the victim. The listening devices are highly sensitive microphones that can listen
for a person who may be moving or attempting to respond to rescuers calls. This
hole process can take many hours to search one building. If a person is found
extrication can take even longer. This paper presents the developments of a modular
robot system towards USAR applications as well as the issues that would need to
be addressed in order to make such a system practical. SERPENTINE
RESCUE ROBOTS: LEADING APPROACHES Sensor-Based
Online Path Planning This
section presents multisensor-based online path planning of a serpentine robot
in the unstructured, changing environment of earthquake rubble during the search
of living bodies. The robot presented in this section is composed of six identical
segments joined together through a two-way, two degrees-of- freedom (DOF) joint
enabling yaw and pitch rotation (Fig.), while our prototype mechanism (to be discussed
later in this article) is made of ten joints with 1 DOF each.
Configuration
of each segment The
robot configuration of this section results in 12 controllable DOF. An ultrasound
sensor, used for detecting the obstacles, and a thermal camera are located in
the first segment (head). The camera is in a dust free, anti shock casting and
operates intermittently when needed Modified
distance transform The
modified distance transform (MDT) is the original distance transform method modified
for snake robot such that the goal cell is turned in to a valley of zero values
within which the serpentine robot can nest. Other modifications are also made
to render the method on line
"
Distance transform is first computed for the line of sight directed towards the
intermediate goal, without taking into account sensorial data about obstacles
and free space. This is the goal-oriented planning.
" The obstacle cells
are superimposed on the cellular workspace. This modification to the original
distance transform integrates IR data that represent the obstacles are assigned
high values
<<back |