An Autonomous Navigation Vehicle for Surveillance

Abhilash Jindal Ankur Jain

Faez Ahmed Gaurav Dhama

Mayank Baranwal Palash Soni

Shishir Pandya Sriram Ganesan

ABHYAST is a mobile robotic device designed to be a reliable and rugged platform for

autonomous navigation in both structured and unstructured environment, communication and imaging.

1)Accepts the co-ordinates (latitude, longitude or name) of its destination from GSM network

(e.g. – BSNL, Idea, etc.)

2) Navigates autonomously using obstacle detection ,collision avoidance and path planning

techniques to the destination using IMU assisted GPS, Digital compass and proximity

sensors(Laser Scanner and Infrared Sensor) 3) Takes images in the vicinity of the destination point.

ABHYAST accepts location coordinates in 3 formats:-• Short distance navigation(<100 mt)

Latitude/Longitude acceptedDisplacement Vector accepted

• Long Distance NavigationLatitude/Longitude acceptedLocations name accepted and pre-stored map followed(in structured

environment). Uses GPS and Compass for Absolute Positioning and IMU and Proximity

Sensors for relative short distance navigation. Laser Scanner and IR sensors help in Obstacle detection, Collision

avoidance and Path Planning in short term. Camera used for imaging/video of target location and images stored in

Memory. Task completion communicated to User and Abhyast returns to original

position or as commanded by user.

Packbot

PackBot is a series of military robots by iRobot. More than 2000 PackBots are currently on station in Iraq and Afghanistan, with hundreds more on the way

PackBot easily climbs stairs, rolls over rubble and navigates narrow, twisting passages

The robot relays real-time video, audio and other sensor readings while the operator stays at a safe standoff distance. The operator can view a 2-D or 3-D image of the robot on the control unit, allowing for precise positioning.

Source:- www.irobot.com

Abhyast mass ~8kg

Abhyast Dimensions 30cm x 30cm x 15cm [According to problem statement

OBC BEAGLE BOARD

600 MHz,256 MB RAM & 128 MB Flash

GSM board GSM unit,Simmortal Ltd,SIDBI

Laser Scanner R283-HOKUYO-LASER1 Detectable distance : 0.02 to 4m

IR Sensor SHARP Distance Measuring Sensor Unit

GPS PARALLAX Accuracy:~2m

IMU Sparkfun IMU with 6 Degree of freedom

Digital Compass OceanServer Accuracy – 0.5 degrees

Motors High Torque MECHTEX MOTORS

Camera OMNIVISION Colour Camera

Design considerationsDesign considerations

Terrain adaptation.

Physical space and weight of the vehicle.

Obstacle scaling mechanism.

Choice of Locomotion System.

Choice of Drive System.

Mechanical complexity.

Control complexity.

Choice of locomotion Choice of locomotion systemsystem

Why tracks ?Why tracks ?

Adapt to surface undulations.

Scale obstacles using Flipper Assist Mechanism.

Achieve good stability with its large ground contact area.

Turn in minimum space.

Requires slipping to turn.

Coupled speed and direction.

High frictional losses.

Chassis

Worm gear box

Support beam

Motor

Battery

Sprocket

Electronic components

Tracks

Passive double track Passive double track mechanismmechanism

Passive double track Passive double track mechanismmechanism

This mechanism gives passive adaptability based on a link structure.

Double track mechanism is composed of two tracks driven by a single motor for each side.

Passivity is acquired by attaching the flipper track with the main track through a hinge joint without an actuator.

hinge motor

Flipper tracks

Main tracks

Flipper Assist Flipper Assist mechanismmechanism

Flipper Assist Flipper Assist mechanismmechanism

a. Flippers oriented parallel to the ground.

b. Flippers changing orientation.

c. Flippers oriented at required incline.

Flippers change orientation to adapt to the terrain. They help to scale obstacles.

mechanism: an example mechanism: an example Flipper assistFlipper assist

mechanism: an example mechanism: an example Flipper assistFlipper assist

(1) (2) (3)

(4) (5) (6)

Skid steering mechanism

In skid steering, the thrust of one track

is increased and the other is reduced ,

so as to create a turning moment.

* Theory of Land Locomotion by M.G Bekker

Simpler from mechanical standpoint.

Turning radius is not bounded but maximum speed is limited proportional to the curvature.

Slippage makes skid steering less power efficient than other configurations.

High torque motor of 30kgcm Provides a rpm of 300.

Worm gear box provides a high gear ratio Also effectively locks the flippers

4 Li ion battery packs of 12.6V and 6000mAh. Total power of the 250Wh

Can power the vehicle for approximately1hr. Power losses are quite significant during skid steering. Path planning should minimize the total amount of steered angle as much

as the robotic task can admit. Smooth trajectories are not necessary and turns can be concentrated in a

sharp way.

SOURCE:--Power Analysis for a Skid-Steered Tracked Mobile RobotJes´us Morales, Jorge L. Mart´ınez, Anthony Mandow, Alfonso J. Garc´ıa-Cerezo,Jes´us M. G´omez-Gabriel and Salvador Pedraza

Communication medium will be SMS(Short Message Service). The main functions of the GSM board are as follows:-• Receives destination point coordinates/location name.• Sends the status of the vehicle (Co-ordinates and Health

monitoring) whenever asked by the user.• Sends its co-ordinates if it gets stuck somewhere

A GSM modem is connected to a PC serial port (or to a USB port with an appropriate modem driver) and a GSM Sim Card is inserted in it. This device is capable of most Mobile phone capabilities like SMS ,call and GPRS and it can be controlled via On Board Computer.

Globally prevailing Mobile phone network. Pre established network hence zero cost

input in communication infrastructure development.

Very large distance communication with operator possible.

Low power consumption and reliable mode.

Tasks Achieved

Sending sms to operator’s

mobile

calls to operator’s

mobile

Other functionalities checked

NOTNOTEEData encryption will be implemented to

ensure security.GPRS functionality likely to be used for direct interface via internet also.

Describes the tools used by the vehicle for navigating and positioning itself

Localizing the vehicle with respect to its environment Provide Obstacle Avoidance and Path Planning

SOLUTIONSSOLUTIONS

Effective localization requires both Global and local positioning methods Path Planning is achieved through combined data from various sensors onboard such as GPS ,IMU , Compass and a Laser Scanner

GPSGlobal Positioning System

Satellite transmits messages containing•Sending time•Orbital information

Receiver•Measures the transit time of each message•Computes the distance to each satellite.•Combines these distances with the location of the satellites to determine the receiver's location using geometric trilalteration

Specifications:-•Number of channels: 12•Position accuracy: 2m•Baud Rate: 4800bps (optional 9600, 19300,38400)•Interface: RS232/TTL

Tasks Achieved

Acquiring of NMEA data

Interfacing with PCs

Data consistency

checked

DATA ACQUIRED IN OPEN ENVIRONMENT

$GPGGA: Position Response Message$GPGSA: Satellite Used Response Message

$GPRMC: Recommended Minimum Course Response Message$GPGSV: Satellites-in-View Response Message

• Used to determine the absolute orientation in terms of Roll , Pitch and Yaw data• Would be required on the vehicle to compare its current orientation with respect to the Global map

Image adapted from Wikimedia Commons

Proposed Component :- OS-5000-US compass Specifications :- Provides Roll & Pitch full rotation, typical 1° accuracy

<±30° tilt Pitch Angles +/-90 degrees, Roll Angles +/- 180 degrees Tiny size, 1”x1”x0.3”, less than 2 grams weight Interface through RS-232 and USB Rugged Design :- 10000G Shock Survival High Data Update Rate to 40HZ

• Consists of a LASER rangefinder in a rotating mirror assembly• Proposed Component :- Hokoyu URG-04LX

• Specifications :-

• Gives data with pencil beam viewing at high data rates(38.4 Kbaud or more)• Has an embedded processor which packages data for the host computer• Range- approx. 0.02 to 4m(depends on reflecting surface)• Scanning Area-240 degrees• High Accuracy-10 mm• Resolution-0.36 degrees

Consists of chalking out a strategy for effective terrain traversal

Uses the Laser Scanner to discriminate between drivable and non-drivable terrain

Discrimination is done by extracting the features of the environment pertinent for navigation

Required to provide protection to the vehicle from collisions from objects that may have been overlooked by the laser sensor

Uses IR sensors at carefully placed positions on the vehicle Proposed Sensor :- SHARP GP2D12 distance measuring

sensor Distance measuring range- 10 to 80 cm

Refers to localizing the vehicle with respect to some reference position

Would be accomplished using the principle of Odometry Odometry-Inertial Measurement Unit(IMU)

X

Y

Inertial Measurement Unit•Used for short term navigation via Dead Reckoning•Helps navigation in covered areas•Sensors to measure the acceleration and angular velocities along 3-axis•Design: Strapdown system

•Sensors are mounted rigidly•Output quantities are in body frame instead of global frame

•Proposed component: SEN-08454(IMU 6 degree of freedom)•Features:

•Input voltage: 3.7 V to 7 V •LPC2138 ARM7 processor

•10 bit ADC•SRAM: 32 kB and Flash: 512kB

•3-axis MMA7260Q accelerometer •Range upto +/- 6g•Sensitivity: 200mV/g (for +/6g range )

•Two 2-axis IDG300 gyroscope•Range: +/- 500 °/sec•Sensitivity: 2mV/°/sec

•Minimum acceleration reading: 5 mg•Minimum rate reading: 0.5 °/sec

To assess the obstacle profile as provided by the laser scanner and IR sensors and avoid obstacles accordingly.

To plan the shortest and most optimized pathway to the destination based on the obtained variables.

To calculate the speed, acceleration, angular velocity, inclination etc of the robot and hence monitoring its stability.

To implement motor control as per the requirement. To communicate the position, orientation, locomotion and health data

to the controller unit.

Stands for Mobile Robot Programming Toolkit.

Open Source with extensive online support.

Aids designing and implementation of algorithms for SLAM, computer vision and path planning.

Features extensive support for crucial components and algorithms like probability functions, occupancy grid, kalman filters, ICP etc

Includes a lot of graphical support for mapping and localization and a 3-D simulator as well

Simulation with MRPT

Supports a number of languages including C# and python

Features visual programming capabilities Easy access to sensors and actuators using

premade .NET libraries. Provides a 3-D Simulator with graphic

acceleration for testing of algorithms in simulated world.

Supports a wide range of hardware. Pretty easy to use Academics Version is available for free.

Simulation with Microsoft Robotics Studio

Navigation Technique “Subsumption Technique” will be used for navigation

Escape maneuvering:- Vehicle will try to escape when it gets stuck.In case if the vehicle can’t get unstuck then it will SMS its location to the user and stop all other processes.

Collision Avoidance:- It will navigate through the path avoiding the obstacles based upon the sensor output. Standard algorithms are available for path planning.

Escape maneuversCollision Avoidance and Path planningNavigation towards target location

Highest Priority

Lowest Priority

Freely available from the open street map (OSM) websiteEasily accessible xml formatUser defined map of any region possibleConsists of:-

1- Node2- Way3- Closed way

Example of xml format:-<node id="245737798" lat="25.7341" lon="81.9364" user=“ABHILASH" visible="true" timestamp="2008-02-04T18:14:47+00:00"></node>

Open Street Map

MATLAB Code of our initial algorithmThe Robots trajectory always targets the final destinationIn case of Obstacle in the range of its sensors it follows their boundary.

Case of scattered Obstacles

Case of concentrated obstacles

ABHYAST

ToughTerrain

Safe Navigation

Path Planning

Size,weight

and Power

Reliable communicatio

n

Self Localizatio

n

ComputationData

Handling

CHALLENGES

Disaster Management:-Improvement:-Satellite Phone , Robust Structure

Improved Path Planning with SLAM and Global map making implemented.

Good industry-academia relationship.Exposure to new technologies.Innovation motivated by implementation of ideas in an open ended problem.Gradual development of new technologies.Team Work and standard work practices followed to achieve final goal.

Thank YouThank You