josh report

8/9/2019 Josh Report

http://slidepdf.com/reader/full/josh-report 1/29

SNAKE ROBOTS



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



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



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,



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.



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.



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.



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.



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.



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.



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 .



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



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



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



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.



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:



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.



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.



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.



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.



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.



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



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.



\

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.



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.



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.



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

josh report

Documents