Moksha - Unmanned Ground Vehicle

Published on June 2016 | Categories: Types, Research, Math & Engineering | Downloads: 32 | Comments: 0 | Views: 419
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M S Ramaiah Institute of Technology, INDIA presents

“Moksha” Unmanned Ground Vehicle

Planning

Design

Implementation

Integration

Testing

Fig: Stages of Development of Moksha – UGV

Split Frame Chassis

• Better stability and drive control in terrain conditions. • Ramp climbing ability. • Can take load of 150 kg.

Fabrication
• Laser cut mild steel frame with







welded joints. Steel platform for laptop & compartment for payload. CPVC mounts for camera and GPS. Slide out battery box under the frame. Hood for solar panels.

Power Supply Board and Solar Panels

• Connectors that can handle power surge. • Voltage regulator IC 7805 for providing constant 5v DC supply. • Use of solar cells for recharging the batteries and promoting renewable energy sources.

Sensors Used:
1.

2.
3.

Camera – 5 MP Webcam SONAR Garmin 18x GPS

Material Mild steel Length 3 feet 10 inches Width 2 feet

Height
Wheels Motors Weight

3 feet
4 2(24 VDC,1.8 Amax,120 W) 62 Kg
Hardware Specifications

Motor Controller: RS160D Motors (24VDC 120W) Power Supply System Battery Chassis Safety:
Mechanical stop, Wireless E-Stop, Manual Brake

LV-MaxSonar-EZ1
 The LV-MaxSonar®-EZ1™ is The

EZ1™ is an excellent choice for use were sensitivity is needed along with side object rejection.  The sensor offers three standard outputs (analog voltage, serial data, and pulse width)  The LV-MaxSonar®-EZ products also operate with very low voltage from 2.5V to 5V with less then 3mA nominal current draw.

Garmin 18x USB




The GPS 18x is a, highsensitivity GPS sensor for use in automotive, fleet vehicle, and electronics applications that require a small, highly accurate GPS receiver. Supports non-volatile memory for storage of configuration information, a real-time clock and raw measurement output data in NMEA 0183 format.

RS 160D
 The motor control used is the

RS160D by Robot-Solutions, LLC.The RS160D servo uses custom software to implement a 2.5 channel high-powered servo system.  The RS160D operates in the PWM mode communicating serially with the processor through a RS232 cable.

1. The different devices on the UGV are controlled by a C++

program which includes an algorithm which uses the data from the sensors. 2. The different devices are connected to the processor using the USB ports which are interfaced to the devices using USB to RS232 converters. 3. This is done since the data is exchanged between the processor and the sensors and motor controller serially. 4. From the motor controller, output is sent to the actuators to move the robot.

The camera is placed at an angle facing the ground in front of the vehicle at about 3 feet height The processing of image is done as shown below:
• First the RGB image is converted

Black & White Image

to a gray scale image. • The gray scaled image is processed using Canny algorithm to detect the edges in the image. • Then the resulting image is processed using Hough (Probabilistic) transform to detect only line segments in the image.

After Canny Edge detection

Line Detected using Hough Transform

The data from the GPS is extracted using serial data transfer functions. 2. The destination point is taken by the program and the area around the GPS is divided into 4 quadrants. 3. The current location of the GPS lies in one of the 4 quadrants and based on the quadrant the UGV is located at, the direction and the turning angle is calculated and data is sent to motor controller.
1.

1. The co-ordinates are obtained from the Garmin 18x USB, and then we manually input the destination co-ordinates into a sub-controlling program,

which then continuously calculates the relative angle between the destination point and the present direction of the vehicle.
2. It decides, first, which point is closest to its present location, selects that point, and then makes its angle calculations as follows using “Haversine Formula”.
R = Earth’s radius (mean radius = 6,371km) Δlat = lat2− lat1 Δlong = long2− long1 a = sin²(Δlat/2) + cos(lat1).cos(lat2).sin²(Δlong/2) c = 2.atan2(√a, √(1−a)) d = R.c

3. This data is returned continuously to the main controlling program, where decisions are made.

C++ is used to send data serially instead of HYPERTERMINAL. Data is sent in ASCII format from the processor. The RS160D is a 2 channel controller. Each channel controls 2 different motors(right and left). Data is sent as : “@0sm1” sent as "(right and channel controls one motor. One of the channels is used to control the left motor and the other motor selects mode 1 i.e., PWM mode “@0sj0” selects serial communication mode “@0st255” torque control
LEFT MOTOR @0st120 @0st130 @0st170 @0st170 @0st140 RIGHT MOTOR @0st120 @0st130 @0st170 @0st140 @0st170 UPSHOT
BOTH MOTORS OFF LOW VOLTAGE,VEHICLE MOVES WITH JITTER MOTION,NOT STABLE VEHICLE MOVES STRAIGHT SMOOTHELY AT AVERAGE SPEED OF 2 MPH VEHICLE MOVES RIGHT VEHICLE MOVES LEFT

1.

The implementation of the GPS is based on C++ code to provide high level functions. This algorithm evaluate the safest, shortest path to a given location based on cost calculations.

PRN 2 PRN 12 PRN 18 PRN 8

2. We are using a Brute force algorithm.

Reference Station Differential Correction Pathway

Roaming GPS

3.

Sub-controlling program, continuously calculates the relative angle between the destination point and the present direction of the vehicle.

Hardware Specifications:
 

Software Specifications:




  

Split frame chassis for better stability and drive control. Strong steel frame that can take a weight of 150kg. Rear wheel drive powered by powerful 24V 180W motors controlled by RS 160D Motor Controller. Very small turning radius. Max Speed of 5MPH. Compact size:

Simple and efficient code using Visual C++ and Open Computer Vision library. Image Processing based on Hough Transform. GPS based navigation code capable of driving to specified locations. Mechanical stop, wireless E-Stop and Manual Brakes for enhanced safety.

 

Safety Features:


Length 3ft Width 2 ft Height 4ft.

Sensors Used:
  

LV Max Sonar EZ1 Garmin 18x USB USB PC Camera

REFERENCES
      

Real-Time, Multi-Perspective Perception for Unmanned Ground Vehicles- Anthony Stentz, Alonzo Kelly, Peter Rander, Herman Herman, Omead Amidi, Carnegie Mellon University The Intelligent Ground Vehicle Competition, Rules and Regulations igvc.org/IGVCRules2011V5updatedflagpartnumbers.pdf IGVC Design Reports- igvc.org/reports.htm The Open CV 2.1 C++ approach opencv.willowgarage.com/documentation/cpp/index.html RD 160D by Robot Solutions- robot-solutions.com/RS2/RS160DManual.pdf Distance betwwen latitude/ longitude points using Haversine Formulamovable-type.co.uk/scripts/latlong.html Garmin 18x OEM Manual- delcom-eng.com/downloads/ USBPRGMNL.pdf

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