Design Review

ELECTRO-MAGNETIC MANUAL/AUTONOMO

US CONTROLLED LAUNCHING SYSTEM

(EMMA CLS)

• Thomas Jacobson• Max Macri• Paul Sadaukas

EMMA CLS is a turret that can autonomously track moving objects using image processing.

The device is also capable of user-control via a manual override mode.

The turret provides the user with the ability to launch a projectile from the turret utilizing the onboard electromagnetic launcher.

WHAT IS EMMA CLS?

A device that can perform surveillance work to track moving targets

Can launch a projectile to deter threatsCan rotate or pan to stay fixed on a moving target

CUSTOMER NEEDS

1. Must accurately find moving targets, and track them continuously

2. Must provide video feedback to the user3. User must be able to override the autonomous mode

and manually control the device4. User must be able to fi re a projectile by means of a

user interface

MARKETING REQUIREMENTS

ENGINEERING REQUIREMENTS

Marketing Requirements

Engineering Requirements Justification

1,2,3 Device should contain webcam for transmitting video from device to computer

The device needs to have some way of using video feed both to display the feed to the user, and to use that feed for image processing. A webcam is both a cheap and a widely available means.

1,3 Device should have 270 degrees of horizontal rotation, and 90 degrees of vertical rotation, using at least two servos.

Two servos are the absolute minimum for full 2-dimensional targeting.

1,4 Device should be capable of launching a projectile up to 10 feet away.

The force required to propel the projectile 10 feet should be sufficient to ensure accuracy at closer ranges (the ideal “strike zone”).

3, 4 UI should contain at least four buttons for controlling the turret, a button for firing the turret, and a toggle between auto and manual mode. UI should also contain a section of the screen devoted to displaying the image.

This is the basic user interface that contains all of the basic utilities for controlling the device. Based on actual testing, this design may be subject to change (using the mouse instead of arrow keys to control the device).

4 System must be able to step a nominal voltage of 12V to 300V, with an input current of 100mA (± 20mA).

The voltage of 300V for the capacitor is required to be able to provide enough power to launch the projectile the desired distance. The current requirement ensures that the capacitors will charge at a reasonable rate, with overall charge times of under 60 seconds.

EMMA can be broken down into three main sections: The Software, the Turret, and the Launcher, as can be seen on the next slide.

DESIGN

SYSTEM ARCHITECTURE

Previous designs used pneumatics, which are large and diffi cult to transport

Using an electromagnetic launcher allows for the same amount of force to be used, while maintaining a higher level of mobility

The only moving parts are the servos, which also reduces the wear and tear, and increases the lifespan of the device

CONCEPT SELECTION

Capacitors were chosen as the power source for the launcher because of their ability to hold a large amount of energy and dispel the energy rapidly

Two stage coil design was used to provide a varying amount of power for the launcher, while avoiding the complexity of larger power control circuits

SCR was chosen over other switching mechanisms because it allowed for digital control, triggers faster then relays, and because of its low activation energy requirement

LAUNCHER DESIGN CONCEPT

TURRET DESIGN CONCEPT

Wooden Slab

Servo 2Servo 1

Launcher

Servo inputs (from software)

Video output (to software)Webcam

Charge and Fire commands (from software)

Design 1

Design 2

Design 2 was selected for the project

Design 1 requires Servo 1 to support a large amount of weight

Design 2 has the center of mass directly in the middle of the turret, which makes it sturdier

Design 2 provides a better supported platform for the launcher and webcam

Optical was used over other types of sensors because humans are familiar with vision. Also webcams are cheap, and easy to interface with.

Lucas-Kanade algorithm was used over others, because it provides good balance between resource intensity, and details to track. It can be fine tuned to provide more details, if the computer can handle it.

TRACKING DESIGN CONCEPT

LAUNCHER SUBSYSTEM

S

L 1

13

S

L 0

13

R L 1

43

12

R L 0

43

12

D 1

D 2

MICROCONTROLLER

High Voltage DC-DC

HV- HV+

LV- LV+

R L 2

43

12

V 1

1 2 V d c

R 1 1 kR 21 0 0 k

Bleeder Resistors

] Cap Charge Control

] Read Cap Voltage

Coil1 Trigger

Coil0 Trigger

C h a rg e

C o il1 A c t iv e

S e n s o r0

F ire

S e n s o r1

P ro je c t ile S t a t u s

C h a rg e S t a t u s

+

C 1

1 0 m F

Launcher Design Circuit

THE LAUNCHER SUBSYSTEM

LAUNCHER SUBSYSTEM

R 33 9 0

R 41 0 k

R 55 1 0

U 11

2 4

3

Q 12 N 3 9 0 4

V 45 V d c

0

S e n s o rN

Sensor circuit

THE TURRET SUBSYSTEM

The turret receives new positions from the software subsystem (from either the user, or the tracking software) and updates both servos

SOFTWARE SUBSYSTEM

Steps: 1)Acquire Image2)Compare to next image3)Get the offset between images4)Send difference to driver in (x,y) format

5)Driver sends new position commands to MCU6)MCU sends new position to servos7)Servos are updated to new position, go to 1

THE SOFTWARE SUBSYSTEM

The User Interface

Item Retail Price (per unit) Our Price (per unit) Quantity

Servo $10-20 $0 X2

Webcam $40 $30 X1

450V Capacitors $40 $0 X2

Arduino Microcontroller $25 $25 X1

SCR $12.50 $12.50 X4

IR Emitter/ Collector $3 $0 X2

440V Capacitor $1.65 $0 X1

4.7Kohm resistor $0.20 $0 X1

15Kohm resistor $0.20 $0 X4

500V Capacitor $0.22 $0 X1

SE555P Precision Timer $0.51 $0 X1

68ohm resistor $0.20 $0 X1

1Kohm resistor $0.20 $0 X1

1Mohm resistor $0.20 $0 X1

FEP16HTD Rectifier $1.30 $0 X1

12Kohm resistor $0.20 $0 X1

10Kohm potentiometer $2.75 $0 X1

LM311PE4 TI Comparator $0.72 $0 X1

2200HT-121-V-RC 120uH Inductor

$3.22 $0

 

X1

STW25NM60ND 600V N-channel MOSFET

$5.68 $0 X1

Total Cost $248.85 $105.00 N/A

REQUIRED MATERIALS

All of these parts are standard and have lead times of roughly 1 week (Standard shipping)

The launcher uses large voltages (~400V), which can be dangerous to handle The final design will have a casing around all high voltage

components to prevent accidental shockThe launcher needs to be light enough to that the

turret can move it Non-critical launching components will be placed in the

base of the turret to minimize the amount of weight needed to be moved by the turret’s servos.

The launcher has the potential of breaking if fi red with no ferromagnetic projectile in the barrel. Sensors are used not only to accurately fire the projectile,

but to ensure that the system actually contains a projectile.

LAUNCHER RISKS

Speed: The turret needs to be able to keep up with moving targets. This requires using high speed servos

Torque: The turret needs to be able to bear the weight of the components located on the launching platform

TURRET RISKS

The tracking algorithm needs to balance between computing resources consumed, and accuracy of tracking.

Software needs to switch between tracking a target, and moving to the new position (alternating between the two)

Both of these risks can be avoided through early testing.

SOFTWARE RISKS

Testing will be a cumulative eff ort to ensure any bugs, or design flaws can be caught early, to minimize downtime.

Each Component will undergo separate testing to ensure the components operate as defined in the design documentation, followed by a suite of integration tests to ensure that the pieces all function together properly.

SYSTEM TESTING

The launcher’s sensor system must be tested to ensure the critical projectile sensing features operate properly and in a timely manner.

The charging circuit of the launcher must be extensively tested to ensure that the circuit can handle multiple recharges without damaging components from overwork.

The launcher must be tested to ensure not only that the SCR’s trigger the EM coils and launch a projectile, but that the launching capabilities are repeatable.

TESTING THE LAUNCHER

The turret will be tested to see how fast the servos can turn, while under a variety of loads.

The servo controller will need to be tested to ensure that based on a set of predefined control inputs, that the servos orient in the proper direction.

Tests will also be performed to make sure the servos can maintain continuous movement without breaking down.

TESTING THE TURRET

Initial testing of the control software will just verify that control via the UI/automation software will produce sets of outputs that can appropriately control the turret.

Following the completion of these test, the turret (or servos at least) will be integrated with the software for the remainder of the testing.

Test such as tracking a target and moving the servos “simultaneously” will need to be performed.

The tracking software will be tested to see how well it works in a variety of conditions Variances in lighting, indoor vs. outdoor, against different

backdrops, using different targets.

TESTING THE SOFTWARE

Following the completion of all the individual system tests, the systems will be fully integrated. At this time a series of integration tests will be performed to verify that the pieces function as expected when interacting with each other.

The system will need to hit a moving RC car driving in circles of 2,5,7, and 10 feet from the turret. While the turret is tracking the car, it will need to accurately hit the car upon user input.

FINAL TESTING

We got answers!

QUESTIONS?