Finalized Prototype

Shown below is the finalized prototype. The purpose of the prototype was to demonstrate the feasibility of a small, highly maneuverable search and rescue robot. As such, the completed prototype was successful. Capabilities include a ground speed of 10 inches per second, battery life of 50 minutes, wireless range of between 50 and 150 feet (depending on interference), weight of 14.5 pounds and the ability to climb stairs. The prototype is also capable of crossing a gap of at least 10 inches and of climbing a 21 inch tall ramp angled at 49 degrees from horizontal. It provides the operator with a color video feed (with nighttime illumination) and two-way audio communication.

Finished Prototype

Finished Prototype



Arm Rotation Sensors

The robot also features 4 arm position sensors to indicate the orientation of each leg relative to the body. The sensors are designed similarly to potentiometers with a C-shaped piece of resistive paper. As the arm rotates, it makes contact between the resistive paper and the output terminal. The output voltage is measured with the Arduino's analog inputs.

Schematic of Arm Sensor

Finished Arm Sensor with Wiper



First Entirely Wireless Test

First fully wireless test

This was the second major test of the prototype, the first test done entirely without external connections. Again, the laptop used to send commands and view the camera feed (as well as send and receive audio) is not shown. This test brought to light yet more software and hardware issues, which are being addressed.



Line of sight wireless range test

With the robot set up in the configuration shown in the above video, the team tested the line of sight wireless range. The team was able to remain in control of the robot at a distance of approximately 160 ft. More tests are planned to analyze the impact of structural interference.



First Full Motor Test

First full motor test with wireless control

This was the first major test of the prototype. 6 of 8 motors were connected (all except front left rotation and translation). Some software bugs were discovered in the test and are being fixed. Not shown is the laptop connected wirelessly to the robot which is being used to control the motors. Also note that the camera is working with a video feed being sent to the desktop computer shown in the video.



Construction - March-April 2012

Circuit Board

Circuit Board (with Arduino)

Shown above is the motor controller board connected to an Arduino microcontroller. The board has an accelerometer (red square in first image), a connector for a GPS (small bottom left connector), eight individually controllable motor drivers and power regulation circuitry. Most of the motor drivers are driven by an additional output expanding IC.

The motor drivers and voltage regulators are collinear so that two heat sinks may be attached. Also shown is an ethernet cable to connect the arduino to the ethernet shield.

Electronics testing

Once the motor driver board had been populated the team tested it outside of the robot. At first, a battery was used to power the router, camera and microcontroller. An additional battery was then used to run the motors. The team decided to use two batteries because of the large voltage drops when a motor was turned on. This voltage drop caused undesireable resets by the router and camera.



Construction - February 2012

Prototype Gearbox

Prototype Gearbox

These gearboxes are to be connected to the arms of the robot and will allow the robot to dynamically change the track shape. The gearboxes were constructed and were tested to make sure the assembly would provide enough torque to lift the robot. Shown below is the test setup. Weights were attached to a temporary gear fixed to the end of the output shaft. Voltage and current were recorded and were used to find an appropriate battery.

Gearbox Test

The team also designed and constructed a printed circuit board using Calvin's electronics lab. The finalized design is shown below.

Printed Circuit Board Design



Electronics

Electrical Block Diagram

The RESCUE robot utilizes a WiFi router connected to an ethernet camera and a microcontroller. The operator uses a laptop with a wireless card to communicate with the robot. This provides a simple method for streaming video from the robot to the laptop and allows the robot to operate in tethered mode if desired.



CAD Modeling

Gearing Assembly

Gearing Assembly (with body removed)

Arm assembly with side cover removed

The team developed a CAD model of the RESCUE robot including gearboxes and motor mounts. Most body pieces will be constructed from aluminum due to its light weight.



Preliminary Prototype

Prototype of senior design project

The team plans construction of a robot with four caterpillar tracks which can rotate 360 degrees independently. Target market is reconnaissance in search and rescue situations as well as identification and exploration of a hazardous material environment. First prototype constructed out of legos, but later revisions to be more durable.



About the prototype

For additional details, see design specifications in the Final Report

Prototype Drawing


Meet the team

Matthew DeVries - Mechanical

Matt Johnson - Mechanical

Paul Lyzenga - Electrical

Karl Stough - Electrical


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