CAESAR's capabilities are audio, video and data communication regardless of the orientation of the robot and antennas. Developed analytical models determine the risk of gas concentrations for victims, rescuers and robots.
INTRODUCTION
- Mechatronics
- Motivation for Research and Literature Survey
- Thesis Contribution
- Research Objectives
- USAR Robot Specifications and Requirements
- Mechanical Specifications and Requirements
- Communication Specifications and Requirements
- Electronic and Sensory / AI Specifications and Requirements
- Training and Courses
- Peer-Review Research Publications, Conferences and Presentations
- Summary
The results of tests conducted on 13 different robots confirmed, "limited mobility and unreliable wireless communication are issues that need to be addressed." The recommendation from these studies is that information should be filtered for errors in data. The body had to be designed to withstand temperatures of 200 °C for the duration of the search and rescue operation.
COMMUNICATION
Implemented Communication
- Radio Modules
- Protocols
- IEEE 802.11 Standard
- Robot Communication Protocol
- Communication Procedure
- Modular Approach for Layered Model
- Procedures for Micro-controller Code
This field must be a printable character and not a control character (that is, the character must have an ASCII value between 31 and 127). In the case of the USAR robot, these will be the radio modules that will act as transceivers.
Voice Communication
- Yaesu VX-7R Modifications
- Microphone and Speaker Adapter
The useful features of the Yaesu VX-3E are that it is small in size, light in weight, and can operate at temperatures that may occur at the robot. An earpiece with a microphone was connected to the Yaesu VX-7R radio to allow the controller to communicate with any victims.
Video Communication
A block diagram of the interconnection between the PathFindIR, converter/modulator, microphone, audio preamplifier, video amplifier, and antenna is shown in Figure 2-15. The TV antenna had very poor performance and was replaced with the egg beater antenna.
Antennas
- Quarter-wave Antenna Design
- Eggbeater Shaped Antenna Design
- Loop Shaped Folded Dipole Antenna
- Eggbeater Antenna
Millimeters of the antenna were cut away until the SWR value was very close to 1:1. The quarter wavelength coaxial cable stub must be shortened depending on the speed factor of the transmission line.
Summary
BODY DESIGN & CONSTRUCTION
Chassis Design
- Materials Selection and Design
- Construction
The chassis dimensions were determined by the size of the various modules needed for the robot's performance. Further modeling of the robot was done to evaluate how it would react in certain scenarios and conditions. After the varnish had dried, it was ready to apply the release agent.
Before applying composite materials and phenolic resin, aerosol oil was applied to the surface. After each half of the robot body was cut to the same height and 0.8mm mild steel. After complete assembly of the robot, aluminized Kevlar was glued to the robot body.
Leverage / Flipper Arms
These were spot welded together to allow a snug fit over each half of the chassis. These straps helped pull the two halves of the chassis together with clips. The needle thrust bearings allow the flipper to rotate freely relative to the mounted gear and main drive shaft at the same time.
Diagrams of needle roller bearing, needle thrust bearing, and ball bearing are shown in Figure 3-15. A bracket is attached to the body at the outer ends of the shafts and supports the shaft with another thrust needle roller bearing. To keep the flipper stationary, an 06B sprocket was attached to the flipper via a stud screw which would abut against the lower part of the ball bearing.
Drive / Actuator System
In order to minimize the space taken up by the engines, it was decided not to mount the engines on the body until the fin mechanism was assembled. This was necessary to take into account the needs of the thermal camera, which was supposed to be installed on the front side of the central cavity. The smallest available gear, i.e. 06B 13 tooth, was used on the inside of the body.
Using the scenario of the torque diagram in figure 3-20, the maximum force on the rocker arm can be calculated as shown in equation 14. Each rocker arm set at the front or back will support half the weight of the robot, that is 28 kg. The stress and strain analysis of the flipper arms was performed to determine if these arms could withstand the weight of the robot for the different scenarios.
Tracks
The U-channeling allowed traction over rough terrain, but there was still a possibility of slipping on smooth surfaces. The traction system implemented allows for mobility on smooth and rough terrains of both high and low temperatures. In the event that CAESAR were to tip over, it could change the flipper arms orientation and still keep moving.
Assembly
- Camera Lens
- Body Assembly
A hole is made in the front of the chassis to allow a vantage point for the thermal camera. This was then milled to the correct width to give the shape of the C-channeling. There is also a slot cut into this to allow tensioning of the track by adjusting the sprocket position.
Screw threads were turned into the sides of the axles to allow nuts to be attached where necessary. The gears were milled to the desired thickness so that the tracks could run in the center of the flipper arms. Testing of the pinball arm movement, traction, and movement was performed while the robot was being constructed and assembled.
Summary
A gasket was made with 'Siltech 300 Silicone HT' high temperature acetoxy silicone sealant around the edge of the casings. Siltech 300 Silicone HT' has the properties of being resistant to UV radiation, moisture, extreme temperature fluctuations and tensile stresses and can withstand a maximum temperature of 300 °C. This allowed the two joined halves of the enclosures to be waterproof and keep heat out.
All joints and inserts were sealed with this silicone to make the inside of the robot watertight and to prevent internal explosions that could cause flammable gases.
ELECTRONIC DESIGN
- Power Supply
- Control Unit
- Sensors
- Ultra Sound Sensors
- Flipper and Body Orientation
- Micro-controller Configuration
- Micro-controller Code
- Motor Controller
- Sensor Controller
- Summary
Future research can be performed on the AI from the data received from the robot and the computer can be upgraded if necessary. Avago Technologies HEDS 5500 encoders were used on the flipper arm shafts to determine the angle of the front or rear arms. It was useful to be able to determine the orientation of the robot in relation to the speed and roll of the chassis.
One discontinuity was applied to the angle of the front fin arms, while the other discontinuity was applied to the angle of the rear fin arms. GUI control allows the cursor to hover over the arrow buttons, which then sends instructions to the robot. Body orientation feedback enables local autonomy for best fin arm orientation and pitch angle feedback to the controller.
ARTIFICIAL INTELLIGENCE
- Localization Methods
- CAESAR Localization Method for Semi-Autonomy
- Gas Concentration Decisions
- Gas Analysis
- CAESAR PC AI for Gases
- CAESAR Gases Detection
- RCP Decisions
- Serial Data Received Interrupt
- Packet Analysis and Transmission Packet
- Conclusion
The reference to the front of the CAESAR robot refers to the side moving forward, while the rear is considered the opposite side. A summary of the flipper arm orientation for the CAESAR robot in the normal orientation or upside down orientation is shown in table 5-1. Concentrations of the gases up to the level of the Threshold Level Value (TLV) are considered safe.
Should any of the values become positive, this indicates that the gas concentration is either unsafe, dangerous or flammable. All the solutions of the different gases are needed to determine the safety of the environment. In case the character is not a "#", the array position is incremented and the received character is stored in the receive array.
TESTING AND VERIFICATION
- Communications
- Ultrasonic Distance Sensor Testing
- Gas Sensory System / Control System
- Traction System and Transformability
- CAESAR Prototype
- Field and Scenario Testing
- Summary
Measurements were taken from the output of the circuit connected directly to the microcontroller. The gas sensors were monitored to determine the consistency of the output in a non-fluctuating gas environment. Calibrated sensors available from the fire department verified the gas concentrations.
The CAESAR robot was tested on various terrains to determine the feasibility of towing. The initial velocity is measured for the robot chassis weight, which is 56.5 kg. Lifting is possible with the weight of the robot chassis, but nothing more than that was possible.
CONCLUSION
Achieved Objectives, Specifications and Requirements
CAESAR is capable of withstanding temperatures higher than 200 degrees Celsius, common in lightning fires, for short periods of time. CAESAR is capable of forcing an inclination of 45° for short distances and 30° for longer distances. The weight of CAESAR is 56 kg, but using lighter materials will result in a weaker construction.
Omni-directional communication is possible with the designed antennas, as the robots can be oriented differently in a disaster scenario. With the thermal camera, audio communication with the victims and video feedback of the environment is possible. Research has been done on the telemetry sensor system required in the search for survivors.
Future Work
3] Human-robot interaction during the robot-assisted urban search and rescue at the World Trade Center, Jennifer Casper, Dr. Robin Murphy, IEEE Transactions on Systems, Man and Cybernetics, Part B, Vol. 6] Better Robots Can Help Save Disaster Victims, Kurt Kleiner, January 2006. [7] Robots in Urban Search and Rescue Operations, David Greer, Philip. 12] Evaluating Awareness of Human-Robot Interaction in Search and Rescue, Jean Scholtz, Jeff Young, Jill L.
14] Development of a shape-shifting mobile robot for urban search and rescue, YE Changlong, MA Shugen, LI Bin, Chinese Journal of Mechanical. 19] Performance Standards for Urban Search and Rescue Robots, Elena Messina, Adam Jacoff, Intelligent Systems Division, National Institution of Standards and Technology, 2006. 56] Threshold Limit Values (TLV) and Immediately Dangerous to Life and Health (IDLH) values Reference Information, www.mathesontrigas.com, 25.
Motor Driver Controller Code
Timer/Counter 1 initialization // Clock source: System Clock // Clock value: Timer 1 Stopped // Mode: Normal top=FFFFh // OC1A output: Discon. Noise Canceller: Off // Input Capture on Falling Edge // Timer 1 Overflow Interrupt: Off // Input Capture Interrupt: Off // Compare A Match Interrupt: Off // Compare B Match Interrupt: Off TCCR1A=0x00;. Timer/Counter 2 initialization // Clock source: System Clock // Clock value: Timer 2 Stopped // Mode: Normal top=FFh // OC2 output: Disabled ASSR=0x00;.
Sensor Controller Code
Control Station RCP Code
If the received packet is valid and transmission is required, create the packet to be sent.
Robot Station RCP Code
GUI Interface
GUI Control Code
Private Sub BattCheckBox_CheckedChanged (ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BattCheckBox.CheckedChanged. Private Sub TempCheckBox_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TempCheckBox.CheckedChanged. Private Sub CO2CheckBox_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CO2CheckBox.CheckedChanged.
Private Sub MethCheckBox_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Hanteer MethCheckBox.CheckedChanged. Private Sub H2SCheckBox_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Hanteer H2SCheckBox.CheckedChanged. Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Dim toetser As String.
