Changes

{{rocket-project

{{rocket-project

| header = Prometheus (ARES-4)

| header = Prometheus (ARES-4)

'''Mission Statement''' <br/>

'''Mission Statement''' <br/>

The goal of Prometheus is to demonstrate full roll control of a payload as it descends using actuated fins and a PID controller.

The goal of Prometheus is to demonstrate full roll control of a payload as it descends using actuated fins and a PID controller.

'''Success Criteria'''

'''Success Criteria'''

== Design ==

== Design ==

The rocket is comprised of two sections, the payload and the booster. The two sections completely separate with no shock cord running between them at apogee, allowing the payload to be tested independently with the PID controller while the booster is recovered as normal. The separation for Prometheus is unconventional in both its need for complete airframe separation and its use of cable cutters for a reefing system. The reefing allows us to implement a single tube dual deployment, which is necessary since the payload section must remain as one continuous piece.<br />

The rocket is comprised of two sections, the payload and the booster. The two sections completely separate with no shock cord running between them at apogee, allowing the payload to be tested independently with the PID controller while the booster is recovered as normal. The separation for Prometheus is unconventional in both its need for complete airframe separation and its use of cable cutters for a reefing system. The reefing allows us to implement a single tube dual deployment, which is necessary since the payload section must remain as one continuous piece in order to actuate the fins during decent. The addition of canards on the forward half of the rocket effectively push the CP forward such that we can attain a desired stability margin without the need for much additional weight. Our primary material of choice for our airframes and fins is fiberglass, due to its thermal and structural benefits.

 

The addition of canards on the forward half of the rocket effectively push the CP forward such that we can attain a desired stability margin without the need for much additional weight, allowing the rocket to reach superonic speeds. As such, our primary material of choice for our airframes and fins is fiberglass, due to its thermal and mechanical properties.

== Systems Overview ==

== Systems Overview ==

The unloaded mass of the system is 17.1 lbs and 27.8 lbs loaded, using a CTI M1230 motor. Both the forward and aft airframes contain an avionics bay with dual altimeters that will control the separation and reefing charges, executed by redundant cable cutters. The forward airframe will additionally contain the avionics necessary for the PID controller including a Raspberry Pi B+, a Teensy 3.2, 9-DOF Absolute Orientation Sensors from Adafruit, a Big Red Bee GPS Radio, servos to control the fins, and several cameras. The aft airframe will contain an additional GPS radio using a different frequency to ensure recovery of the booster section.

The unloaded mass of the system is 12.9 lbs and 25.5 lbs loaded, using a Cesaroni Pro75 L395. The center of gravity is at 52.19”, and the center of pressure is at 61.45”, giving us a stability of 2.55 cal. Both the forward and aft airframes contain an avionics bay with dual altimeters that will control the separation and reefing charges, executed by redundant cable cutters. The forward airframe will additionally contain the avionics necessary for the PID controller including a Raspberry Pi B+, a Teensy 3.2, redundant 9-DOF Absolute Orientation Sensors from Adafruit, a Big Red Bee GPS Radio, servos to control the fins, and several cameras. The aft airframe will contain an additional GPS radio using a different frequency to ensure recovery of the booster section.

== Propulsion ==

== Propulsion ==

The rocket will be powered by a M1230 from Cesaroni, which was chosen for several reasons. First, it allows us to attain our desired apogee ~ 10,000ft, and second, this is a 75mm M motor which will allow us sufficient room on the exterior of a 98-75mm motor adapter to mount our static stability fins.

The unloaded mass of the system is 12.9 lbs and 25.5 lbs loaded, using a Cesaroni Pro75 L395. The center of gravity is at 52.19”, and the center of pressure is at 61.45”, giving us a stability of 2.55 cal. Both the forward and aft airframes contain an avionics bay with dual altimeters that will control the separation and reefing charges, executed by redundant cable cutters. The forward airframe will additionally contain the avionics necessary for the PID controller including a Raspberry Pi B+, a Teensy 3.2, redundant 9-DOF Absolute Orientation Sensors from Adafruit, a Big Red Bee GPS Radio, servos to control the fins, and several cameras. The aft airframe will contain an additional GPS radio using a different frequency to ensure recovery of the booster section.

=== Motor Performance ===

=== Motor Performance ===

[[File:ThrustCurve M1230.png | right |650px]]

[[File:CTI_L395.png | right |550px]]

{|

{| class="wikitable"

|align="right"| Motor

|Motor

| M1230

| Pro75 4937L395-P

|-

|-

|align="right"| Type

| Type

| Reloadable

| Reloadable

|-

|-

|align="right"| Diameter

| Diameter

|

| 2.95 in (75 mm)

|-

|-

|align="right"| Length

| Length

|

| 29.8 in

|-

|-

|align="right"| Total Weight

| Total Weight

|

| 5706 g

|-

|-

|align="right"| Prop. Weight

| Prop. Weight

|

| 3423 g

 

|-

|-

|align="right"| Avg. Thrust

| Avg. Thrust

|

| 393.7 N

|-

|-

|align="right"| Max Thrust

| Max Thrust

|

| 587.5 N

|-

|-

|align="right"| Total Impulse

| Total Impulse

|

|936.8 Ns

|-

|-

|align="right"| Burn Time

| Burn Time

|

|12.54 s

|-

|-

|align="right"| ISP

| ISP

|

|147.08 s

|}

|}

=== Flight Characteristics ===

=== Flight Characteristics ===

{|

{| class="wikitable"

|align="right"| Apogee

| Apogee

| 10790 ft

| 11,889 ft

|-

|-

|align="right"| Max Velocity

| Max Velocity

| 1154 ft/s (Mach 1.04)

| 825 ft/s  

|-

|-

|align="right"| Max Acceleration

| Max Acceleration

| 374 ft/<math>\exp{s}{2}</math>

| 131ft/s²

|-

|-

|align="right"| Ground Hit Velocity

| Ground Hit Velocity

| 12.6 ft/s

| 12.6 ft/s

|-

|-

|align="right"| Time To Apogee

| Time To Apogee

| 23.7 s

| 23.7 s

|}

|}

=== Fins ===

=== Fins ===

We currently estimate the fins to be 4“ x 4” squares constructed out of fiberglass. As we develop a more realistic model for our system for our control law, we will be able to more accurately determine how large of an area our fins will need to cover to exert the necessary torque to resist rotation.

We currently estimate the fins to be 4” x 4” x 3/32” squares constructed out of fiberglass. As we develop a more realistic model for our system for our control law after we receive orientation data from a test flight, we will be able to more accurately determine how large of an area our fins will need to cover to exert the necessary torque to resist rotation. The fins will be connected on a worm gear mechanism, in order to prevent movement on accent, consequently protecting the fins from any kind of unintentional actuation.

For our stability fins on our aft airframe, we will be using off-the-shelf fins from Giant Leap Rocketry with the root chord of 8.5“, tip chord of 4”, and height of 8.5&quot;.

For our stability fins on our aft airframe, we will be using off-the-shelf fins with the root chord of 8.5”, tip chord of 4”, and height of 8.5”, and a Coefficient of drag of 0.14.

=== Airframes ===

=== Airframes ===

== Avionics ==

== Avionics ==

The payload and the booster sections will each contain two altimeters for redundancy (four altimeters total). Each altimeter will be wired up to the ejection charges mounted on the respective avionics bays as well as to a cable cutter for our reefing system. Since both the payload and booster section will be reefed, there will be redundant cable cutters for both parachutes as well (four cable cutters total). The reefing system will be discussed in detail in '''2.7 Recovery'''.

The payload and the booster sections will each contain two altimeters for redundancy (four altimeters total). Each altimeter will be wired up to the ejection charges mounted on the respective avionics bays as well as to a cable cutter for our reefing system. Since both the payload and booster section will be reefed, there will be redundant cable cutters for both parachutes as well (four cable cutters total). The reefing system will be discussed in detail in [[#Recovery|Recovery]].

=== APRS Transmission ===

=== APRS Transmission ===

== Avionics ==

== Avionics ==

The main controller for our payload will be a Teensy 3.2 from PJRC. This micro controller not only is compatible with Arduino code and the Arduino IDE, but contains a host of additional features including an ARM processor, 2 I<math>^{2}</math>C channels, and capabilities to connect to a CAN bus.

The main controller for our payload will be a Teensy 3.2 from PJRC. This micro controller not only is compatible with Arduino code and the Arduino IDE, but contains a host of additional features including an ARM processor, 2 I²C channels, and capabilities to connect to a CAN bus.

=== Sensor Fusion ===

=== Sensor Fusion ===

See https://www.overleaf.com/3972499sxgwkz. Kalman filtering and sensor fusion (see figure [fig:fusion]) will be used to get accurate and fault-tolerant values for orientation, position and velocity.

See [https://www.overleaf.com/3972499sxgwkz this document for our research].  

 

Kalman filtering and sensor fusion will be used to get accurate and fault-tolerant values for orientation, position and velocity.

[fig:fusion]

[fig:fusion]

(orientation) at (0.5,-2.5) <span>'''Orientation'''</span>; (velocity) at (2.5,-1.25) <span>'''Velocity'''</span>; (angvel) at (0,-1.25) <span>'''Angular velocity'''</span>; (position) at (3.5,-2.5) <span>'''Position'''</span>;

(orientation) at (0.5,-2.5) <span>'''Orientation'''</span>; (velocity) at (2.5,-1.25) <span>'''Velocity'''</span>; (angvel) at (0,-1.25) <span>'''Angular velocity'''</span>; (position) at (3.5,-2.5) <span>'''Position'''</span>;

(tmp) at (1.5,-1); (mag)–(tmp); (acc)–(tmp); (tmp)–(orientation); (gyro)–(angvel); (angvel)–(orientation); (acc)–(velocity); (gps)–(velocity); (velocity)–(position); (gps)–(position); (baro)–(position);

(tmp) at (1.5,-1); (mag)–(tmp); (acc)–(tmp); (tmp)–(orientation); (gyro)–(angvel); (angvel)–(orientation); (acc)–(velocity); (gps)–(velocity); (velocity)–(position); (gps)–(position); (baro)–(position); -->

= Manufacturing &amp; Assembly =

= Manufacturing &amp; Assembly =

| April 2, 2016

| April 2, 2016

|}

|}

= Conclusion =

= Conclusion =

 

[[Category:Rockets]]

[[Category: Rockets]]

[[Category: Documentation]]