ABHYAST

1. ABHYAST An Autonomous Navigation Vehicle for Surveillance

2. introduction ABHYASTis amobile robotic device designed to be a reliable and rugged platform for autonomous navigation in both structured and unstructured environment, communicationand 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.

3. Description • ABHYAST accepts location coordinates in 3 formats:- • Short distance navigation(<100 mt) • Latitude/Longitude accepted • Displacement Vector accepted • Long Distance Navigation • Latitude/Longitude accepted • Locations 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.

5. DEVELOPMENT OF NAVIGATION TECHNIQUES

6. State of Art 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

7. Proposed System Overview • 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

8. Body engineering

9. Design 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.

10. Choice of locomotion system

11. 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.

12. Vehiclestructure Motor Chassis Battery Electronic components Tracks Support beam Worm gear box Sprocket

13. Passive double track mechanism • 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

14. Flipper Assist mechanism • Flippers change orientation • to adapt to the terrain. • They help to scale obstacles. • Flippers oriented • parallel to the ground. b. Flippers changing orientation. c. Flippers oriented at required incline.

15. mechanism: an example Flipper assist (1) (2) (3) (4) (5) (6)

16. Kinematics of the vehicle

17. Drive Mechanism • Skid steering mechanism • In skid steering, the thrust of one track isincreased and the otherisreduced , so as to create a turning moment. * Theory of Land Locomotion by M.G Bekker

18. Somefeatures of skid steering • Simplerfrommechanicalstandpoint. • Turning radius is not bounded but maximum speed islimitedproportional to the curvature. • Slippagemakesskid steering less power efficient thanother configurations.

19. Torque and power transmission • High torque motor of 30kgcm • Provides a rpm of 300. • Worm gear box provides a high gear ratio • Also effectively locks the flippers

20. Batteries • 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

21. GSM MODULEGlobal System for Mobile communications • 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.

22. Advantages of gsm modem Tasks Achieved • 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. Sending sms to operator’s mobile calls to operator’s mobile NOTE • Data encryption will be implemented to ensure security. • GPRS functionality likely to be used for direct interface via internet also. Other functionalities checked

23. Navigation and Localization Describes the tools used by the vehicle for navigating and positioning itself

24. The Fundamental Problems • Localizing the vehicle with respect to its environment • Provide Obstacle Avoidance and Path Planning SOLUTIONS • 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

25. GPS Global 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 ACQUIRED IN OPEN ENVIRONMENT Data consistency checked

26. $GPGGA: Position Response Message $GPGSA: Satellite Used Response Message $GPRMC: Recommended Minimum Course Response Message $GPGSV: Satellites-in-View Response Message

27. 3D Compass • 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

28. 3DCOMPASS • 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

29. Laser Scanner • 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

30. Feature Extraction and Association • 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

31. IMMEDIATE Obstacle Avoidance • 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

32. Relative Localization Techniques • Refers to localizing the vehicle with respect to some reference position • Would be accomplished using the principle of Odometry • Odometry-Inertial Measurement Unit(IMU) Y X

33. 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

34. 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

35. ON BOARD COMPUTER

38. Main Functions of OBC • 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.

39. SIMULATION ENVIRONMENTS

40. MRPT • 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

42. Microsoft Robotics Studio • 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

43. Navigation Technique “Subsumption Technique” will be used for navigation Highest Priority • Escape maneuvers • Collision Avoidance and Path planning • Navigation towards target location Lowest Priority 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.

44. Open Street Map • Freely available from the open street map (OSM) website • Easily accessible xml format • User defined map of any region possible • Consists of:- • 1- Node • 2- Way • 3- 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>

45. Navigation Code Output • MATLAB Code of our initial algorithm • The Robots trajectory always targets the final destination • In case of Obstacle in the range of its sensors it follows their boundary. Case of scattered Obstacles

46. Case of concentrated obstacles

47. C H A L L E N G E S Tough Terrain Safe Navigation Path Planning ABHYAST Size, weight and Power Self Localization Reliable communication Computation Data Handling

49. Future Directions • Disaster Management:- • Improvement:-Satellite Phone , Robust Structure • Improved Path Planning with SLAM and Global map making implemented.

50. Advantages to IIT Kanpur • 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.