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8/9/2019 Josh Report
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SNAKE ROBOTS
8/9/2019 Josh Report
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CONTENTS
1. INTRODUCTION
2. FUNCTIONS OF RESCUE ROBOTS
3. MAJOR RESCUE PROLEM
4. DESIGN OF THE SNAKE ROBOT
5. WORKING OF THE SNAKE ROBOR TO THE RESCUE
6. REQUIREMENTS OF THE RBOCOP RESCUE7. SENSOR BASED ON LINE PATH PLANNING
8. DIFFERENT TYPES OF MOVEMENT
9. FUTURE WORKS
10. CONCLUSION
11. REFERENCES
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ABSTRACT
The utilization of autonomous intelligent roots in search and
rescue (SAR) is a new and challenging field of Robotics dealing
with the task in extremely hazardous and complex disaster
environments. Autonomy, high mobility, robustness and
modularity is critical design issues of rescue robotics requiring
dexterous devices equipped with the ability to learn from prior experience, adaptable to variable types of usage with a wide
enough functionality under different sensing modules and
compliant to environmental and victim conditions. Intelligent,
biologically inspired mobile robots and in particular serpentine
mechanisms have turned out to Widely used robot effective,
immediate and reliable responses to many SAR operations. This
article puts a special emphasis on the challenges serpentine search
robot hardware, Sensor-based path planning and control design.
Presented by:
JOSHUA CLEMENT .C
Roll No: 40
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INTRODUCTION
The utilization of autonomous intelligent robots in the search
and rescue (SAR) is a new and challenging field of robotics,
dealing with tasks in extremely hazardous and complex disaster
environments. High mobility, robustness etc are design issues of
rescue robots equipped with various devices such as devices
having ability to learn from previous rescue, devices adaptable to
variable types of working conditions. Looking to the future,intelligent biologically inspired mobile robots, i.e. serpentine
mechanisms are widely used robots in the field of SAR operations.
Recent natural disasters and man-made catastrophes have
focused attention on the area of emergency management arid
rescue. These experiences have shown that most government¶s
preparedness and emergency responses are generally inadequate in
dealing with disasters. Considering the large number of people
who have died due to reactive, spontaneous, and unprofessional
rescue efforts resulting from a lack of adequate equipment or lack
of immediate response, researchers have naturally been developingmechatronic rescue tools and strategic planning techniques for
planned rescue operations. Research and development activities
have resulted in the emergence of the field of rescue robotics,
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which can be defined as the utilization of robotics technology for
human assistance. This article puts a special emphasis on the
challenges of serpentine search robot hardware, sensor based path
planning and control design.
RESCUE ROBOTS
y Recent natural disasters and man-made catastrophes have
focused attention on the area of emergency management andrescue. These experiences have shown that most
government¶s emergency responses are generally inadequate
in dealing with disasters.
y Considering the large number of people died due to reactive,
spontaneous and unprofessional rescue efforts research have
naturally been developing mechatronic tools and planning
techniques for research operation.
y This factor lead to the development of rescue robots for
human assistances in any phase of rescue operations which
may vary from country to country(different type of disaster,
different regional policies).y The main aspects of rescue robots are detection and
identification of living bodies with the help of most modern
mechatronic tools.
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FUNCTIONS OF RESCUE ROBOTS
1. Detection and identification of livings bodies using modern
tools. Sensors are used to detect the bodies.
2. Clearing of debris in accessing the victim.
3. Physical, emotional and medical stabilization of the survivor
by bringing to him or her automatically administered first aid.4. Fortification of the living body for preventing further damage.
5. Transportation of the victim with necessary first aid.
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MAJOR RESCUE PROBLEMS
y Nondexterous tools are generally cumbersome and
destructive . So the operation of tool is very complicated and
requires great attention.
y Debris-clearing machines are heavy construction devices. So
when they function on the rubble, trigger the rubble.
y Tool operation is generally very slow . It takes so much time
which might result in the death of victim.
y Although a few detectors are available , the search for
survivors is mainly based on sniffing dogs and human voices,
where calling and listening requires silences and focused
attention that is very difficult.
y The supply of first aid can only be done at close distances.
y The retrieval of bodies generates extra injuries since
professional stabilization of the victim is seldom obtained.
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Aiming at enhancing the quality of rescue and life after
rescue, the field of rescue robotics is seeking dexterous devices
that are equipped with learning ability, adaptable to various
types of usage with a wide enough functionality under multiple
sensors, and compliant to the conditions of the environment and
that of the person being rescued.
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DESIGN AND CONSTRUCTION
This chapter contributes a novel design combining the simplicities
of trunk with the agility of trunk, resulting in a continuum robotthat is not only mechanically simple and easy to build but alsorobust and efficient.
Trunk is flexible, elastic and has good strength, but iscomplex to build and control because of the multiple pressurizedcentral members that make the design mechanically challenging.trunk, on the other hand, is much less complex to build and control
because of the single central member and the use of cables asactuators but lacks flexibility and strength due to high cablefriction which cannot be overcome by low pressure in the centralmember, resulting in cable binding which in turn causesundesirable movements of the trunk.
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The trunk presented in this chapter is not only easy to buildand control but also provides good strength and flexibility for thecontinuum robot. This chapter presents a novel approach for
building a continuum robot that replaces the dryer hose, the problematic central member of trunk, with a latex rubber tube thathas more strength and flexibility . Like many previous designs , thecentral member is surrounded by three cables separated by 120degree intervals . Figure shows a cross-sectional view of the trunk explaining the arrangement of cables around the trunk. The lengthsof these three cables define the shape of the continuum robot . The
central member is made up of a latex rubber tube covered with anexpandable nylon sleeve. A rubber tube is a better choice for
building a continuum robot than a dryer hose because of itsflexibility, elasticity and strength. A rubber tube can handle
pressures up to 483 kPa whereas a dryer hose can be pressurizedonly up to 13.8 kPaIn addition, this approach uses only one pressurized member per section which makes it a simpler mechanical design than that of
trunk. The length of this member can be changed by varying the pressure in the member. When pressurized, a rubber tube expandsin all directions like a balloon. To restrict the expansionlongitudinally without losing its cylindrical shape, it is coveredtightly with an expandable nylon sleeve. Various sizes of rubber tubes and matching sizes of nylon sleeves that were experimentallydetermined are shown in Table 1. The rubber tube is sealed on bothsides with a metal tube fitting. One end is permanently blocked. Asmall air inlet is placed on the other end. Hose clamps are used tohold the sleeve, tube and fittings in place. The physical dimensionsof the tube and sleeve affect the amount of expansion at a given
pressure.
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CONTROLING OF SNAKE ROBOT
This section of the chapter presents the design of an electricalsystem to control a continuum robot. Figure provides an overviewof the electrical setup. A host PC calculates the lengths , andneeded to obtain the required shape of a trunk. It then passes these
parameters to the PC/104 module, a compact form-factor single board computer suitable for executing real-time applications andsupported by a wide variety of off-the-shelf I/O boards. 1l 2l 3l
The PC/104 module acts as a driver that actuates the motorsto adjust the lengths of cables. The striking feature of this design isthe two-level control using a PC and PC/104, which accelerates thedevelopment and prototyping process. A Simulink model isdeveloped on the host PC and converted to executable code usingthe Real Time Workshop .
This executable code is then downloaded from the host PC tothe PC/104 running the xPC Target real-time kernel . The PC/104handles the I/O operations through its add-on boards and acts as adriver for the end effectors. The wide variety of commercial, off-the-shelf I/O add-on boards for PC/104 systems coupled with theavailability of drivers for many of these included in Matlab¶s xPCTarget provides a cost-effective rapid-prototyping environment. In
addition, this two-level design utilizes the greater computationalability of a host PC by tasking it with performing the major computational work required to calculate the kinematics of acontinuum robot and providing a real-time graphical representationof a continuum robot .
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This graphical model provides essential feedback to the userswhile they operate the robot. The overview of the electrical designarchitecture is shown in the block diagram. The process is initiatedwhen the user uses the joystick connected to PC to control the
continuum trunk. The joystick used is standard joystick that iswidely available in the market which features three axes, 12
buttons and one throttle. The joystick is connected. The input datareceived from the joystick is then assembled into packets of data to
be transmitted to the PC/104 via the UDP protocol.
Next, the PC/104 receives the joystick data sent by the PCvia the UDP protocol and unpacks it into positions for all joystick
axes and buttons . The required signals are then routed to thedigital-to-analog converter, a Diamond Ruby-mm-1612 expansion board for the PC/104 capable of providing 16 analog outputs with12-bit resolution and supported by drivers included in Matlab¶sxPC target toolbox.
The digital-to-analog converter converts the joystick axis positionto an analog voltage which supplies input to an Advanced MicroControls Z12A8 dual H-bridge . Three motors powered by the H-
bridges actuate the trunk by determining the lengths of threeequally-spaced cables which travel along a trunk composed of a
pressurized latex rubber tube covered with a nylon sleeve andsealed on one end. By varying the cable lengths differentconfigurations of the continuum robot can be obtained.13l d to PC via a USB port.
The receive module receives the motor actuation signals from the
PC via UDP and the send module sends the encoder values to thePC in the same way. The motors can be mounted with encodersthat continuously measure the rotation of the shaft. With thediameter of the shaft known, the encoder reading can be used tofind the lengths of the three cables 13l . These measured lengthscan then be compared against the desired lengths to provide
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closed-loop control over cable length. An Accessio 104-quad-8, aquadrature encoder expansion board for the PC/104 reads theencoder values.
Because Matlab does not provide built-in support for this board, a custom driver was developed in the C language for the board to work with Matlab¶s xPC target toolbox . The capturedencoder values are then packed and transmitted to the PC via theUDPprotocol
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The host PC then receives the encoder values and can compare theactual values against the required values and make corrections tothe lengths 13l to achieve the desired configuration of thecontinuum robot. A simulation of the actual and required
configurations of the robot can also be seen on the PC during this process. A 3D graphical view of the trunk can be drawn using theactual values from user and encoder feedback which can enable theuser to understand the operation of continuum robot much easier during real-time operation. The fourth chapter provides an in-depthdiscussion of the creation of a 3D view of the robot
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WORK ING OF THE SNAKE ROBOT TO THE RESCUE
Ultra sonic sensors and thermal camera are located on its head
the main function of the ultra sonic sensors is detect and
identification of the living body six to seven segments are joined
together by TWO DEGREE OF FREEDOM then all modes are
controlled over here they are as follows:
1. Twisting modeIn this mode the robot mechanism folds
certain joints to generate a twisting motion within its body,
resulting in side wise movement.
2. Wheeled-locomotion modeThis is one of the common
wheeled-locomotion modes where passive wheels are
attached on the units, resulting in low friction along thetangential direction of the robot body line and increasing the
friction in the direction perpendicular to that.
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3. Bridge modeIn this mode the robot configures itself to
³stand´ on its two legs in a bridge-like shape. The basic
movement consists of left-right swaying of the center of
gravity (bipedal locomotion). Motions such as somersaulting
may be other possibilities.
4. Ring modeThe two ends of the robots are brought together
by its own actuation to form a circular shape. The drive to
make uneven circular shape is achieved by proper
deformation and shifting of the center of gravity.5. Inching modeThe robots generates a vertical wave shape
using its units from the rear end and propagates the ³wave´
along its body, resulting in the net advancement in its
position.
Stepper motor is located below, it take the snake from line mode
to the bridge mode then ultra sonic sends the signals and it detects
the human voice or the body heat and goes to the final goal (i.e.
where the victim is there) after moving the debris. Then the victim
is taken out and the first aid is given to the victim with the human
help. It will be occupied with the rescue equipments. Diagram of
the snake robot to the rescue is shown below:
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REQUIRMENTS OF ROBOCUP RESCUE
Basic Real Disaster:
Disaster information collector- Real world interface- Action
command transmission
1) Seismometer 1) Traffic signals2) Tsunami meters 2) Evacuation Signals
3) Video cameras 3) Electricity controls
4) Mobile Telecommunications 4) Rescue Robots
Design of rescue robots mainly aims at the flexibility of
design rescue usage in disaster areas of varying property. Any two
disaster do no have damage alike and no to regions are likely to
exhibit similar damage. Thus rescue robots should be adaptable,
robust and predictive in control when facing different and
changing needs. They should be intelligent enough in order to
handle all disturbances generated from different source.
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The rescue robot needs virtual experiences and training. It
should take optimal action in disaster. It should be equipped with
parties of rescue, fire fighters and back supports.
Rescue robots should be equipped with a multitude of sensors
of different types. Sensors are the weakest component of the rescue
system. They should be robust enough in data collection and
enough intelligence to minimize errors. Multiple inexpensive and
accurate sensors should be used so that the robotic structure can bemanufactured cheaply and used in rescue operations.
SENSOR BASED ON LINE PATH PLANING
This sections 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). The robot configuration of this section results
in 12 controllable degrees of freedom. Ultrasound sensors used
for detecting the obstacles and a thermal camera are located in
the first segment (head). The camera is dust free, anti-shock
casting and operates intermittently when needed. Twelve
infrared (IR) sensors e=are located on the left and right of the
joints of the robot along its body.
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DIFFERENT TYPES OF MOVEMENT
The locomotion of the snake-like robot is achieved by
adapting the natural snake motions to the multisegment robot
configuration. For the current implementation, the robot has four
possible gaits that result in four possible next states.
Move forward with rectilinear motion or lateral undulation (two
separate gaits):In rectilinear motion, the segments displacethemselves as waves on the vertical axis. In lateral undulation,
the snake segments follow lines of propagating waves in the
horizontal 2-D plane.
Move right/left with flapping motion (flap right/left): In
flapping, two body parts of the robot undergo a rowing motion
in the horizontal plane with respect to its center joint and then
pull that center. This results in parallel offset displacement.
Change of direction right/left with respect to the pivot located
near the middle of the robot: The robot undergoes a rotation in
the horizontal plane to the right or left with respect to the joint at
or nearest to the middle of the snake.
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j Twisting mode: In this mode, the robot mechanism folds
certain joints to generate a twisting motion within its body,
resulting in a side-wise movement.
j Wheeled-locomotion mode: This is one of the common
wheeled-locomotion modes where passive wheels (without
direct drive) are attached on the units, resulting in low
friction along the tangential direction of the robot body line
and increasing the friction in the direction perpendicular to
that .j Bridge mode: In this mode the robot configures itself to
³stand´ on its two end units in a bridge-like shape. This
mode has the possibility of implementing two-legged
walking-type locomotion. The basic movement consists of
left-right swaying of the center of gravity in synchronism
by lifting and forwarding one of the supports like, bipeclal
locomotion. Motions such as somersaulting may be other
possibilities.
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j Ring mode: The two ends of the robot body are brought
together by its own actuation to form a circular shape. The
drive to make the uneven circular shape rotate is expected
to be achieved by proper deformation and shifting of the
center of gravity as necessary.
j Inching mode: This is one of the common undulatory
movements of serpentine mechanisms. The robot generates
a vertical wave shape using its units from the rear end and
propagates the ³wave´ along its body, resulting in a net
advancement in its position.
The following sections will consider the twisting mode and the
wheeled locomotion mode and will present some of the
preliminary results.
Twisting Mode of LocomotionIn the twisting mode, two of the joints of the robot body are
bent in a way that the rest of the body experiences a twisting force,
resulting in a side-wise shift after each twist. Since, in this case, no
other parts of the robots are moved, the robot can effectively be
considered as a three link robot. Since, in this mode, the number of
actuated joints is very small, this is a very fault-tolerant mode of
movement. Even in the case of the failure of a number of joints,
this mode may be applicable.
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Wheeled Locomotion Mode
To realize smooth, undulatory serpentine movement, it has
been shown that there must be a large difference between the
friction along the tangential direction and the perpendicular
direction at any point of the robot body. In the present work,
drive-less, passive wheels are attached to the units. This makes
it possible to achieve that necessary condition of undulatory
motion.
If a sinusoidal drive is applied to the joints with proper
positional phase difference, the mechanism will move forward
following a serpentine curve. In this mode, it is possible to get
faster locomotion on a relatively flat surface. On the other hand, onuneven or irregular surfaces, this mode of locomotion is not likely
to be an effective option. Also, in the case of surfaces with very
low friction (e.g., over ice), efficiency is likely to be low.
The frames are taken at an interval of 4 s, and the distance
scale is marked with 50-cm separation. In the prototype, ten units
are connected with 90° offset of the joint axis. Thus, five of the
units are actually in contact with the floor. In the experiment
shown, actuation was given to those five units only, and the other
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joints are kept fixed. Those fixed joints may also be driven if
movement in the third dimension is desired. In the experiment, the
actuations are designed to generate a sinusoidal angular
displacement of joint axes with a frequency of 0.12 Hz. The
amplitude of angular oscillation of the active joints was selected to
be 24°. The sinusoidal drives between the consecutive active joints
are time shifted by an amount of 1.75 s. The resulting net forward
motion of the robot was 4.0 cm/s.
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\
CONCLUSION
Recent natural disasters and man-made catastrophes have focused
attention on the area of emergency management rescue .Theseexperiences have shown that most government¶s preparedness and
emergency responses are generally inadequate in dealing with
disasters. Considering the large number of people who have died
due to reactive, spontaneous, and unprofessional rescue efforts
resulting from a lack of adequate equipment or lack of immediate
response, researchers have naturally been developing mechatronic
rescue tools and strategic planning techniques for planned rescue
operations.Aiming at the enhancing the quality of rescue and life
after rescue, the field of rescue robotics is seeking dexterous
devices that are equipped with learning ability , adaptable to
various types of situations.
Considering various natural disasters and man-made catastrophes
need for rescue robots is focused.
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Research and development activities have resulted in the
emergence of the field of rescue robotics, which can be defined as
the utilization of robotics technology for human assistance in any
phase of rescue operations, which are multifaceted. Research and
development are going on for further modification of rescue
robots.
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Future Work
There is a wide possibility for improvement in mechanical
design, where lighter and stronger materials can be used to
increase the overall strength, accuracy and flexibility of the trunk
can be improved. Replacing PC104 modules with PIC24
microcontrollers may provide much simpler, cheaper and faster
prototyping.
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REFERENCE
1. Snake Robots to the Rescue: by Aydan M.Erkmen, Ranjaith
Chatterjee and Tetsushi Kamegawa.IEEE-ROBOTICS AND
AUTOMATION.SEPTEMBER 2002
2. Working with Robots in disasters: by Tomoichi takahashi
and Satoshi Tadokoro.IEEE-ROBOTICS AND
AUTOMATION DECEMBER 2002
3. Be Prepared: by Louise K.Comfort.IEEE-ROBOTICS ANDAUTOMATION.SEPTEMBER 2002
4. Design ,construction of snake robots :by Srinivas Neppalli
5. www.snakerobots.com