Preliminary Design Review (PDR)
The University Of Michigan
2011
1
Vehicle: i.
2
Vehicle: ii.
Nose
Main Chute Separation Bay
Main Chute Separation
3
Vehicle: iii.
Main Chute Seperation
Aviation Bay
Aviation Bay Access Cut
Apogee Separation Bay
Apogee Separation
4
Vehicle: iv.
Apogee Separation
Apogee Separation Bay
Motor
5
Vehicle Dimensions
 Body
Tube
◦ 5.5 in dia.
 Can
◦ 2.0 in dia.
6
Launch Vehicle Verification
 Vehicle/Payload
design justification
 Static stability analysis
 Materials/system justification
(discussed in further detail in proceeding slides)
7
Vehicle Design Justification
 Different
ideas for reducing drag
 Requirements
◦
◦
◦
◦
◦
Stable
Fast
Precise
Consistent
Highly variable
8
Vehicle Materials
 Nosecone
 Body
 Cans
 Fins
Polystyrene Plastic
Blue Tube (Apogee Comp.)
Blue Tube (Apogee Comp.)
G10 fiberglass
9
Material Justifications
 Phenolic
Tubing
◦ Cured paper fibers
◦ Cheapest, strong, brittle
 Blue
Tube 2.0
◦ High-density paper
◦ More expensive, durable, dense
 Carbon
Fiber
◦ Strands of woven carbon
◦ Most expensive, strongest, labor-intensive
10
Static Stability Margin
 1.5
in neutral configuration pre-launch
 2.4 after engine burnout
◦ Drag mechanism actuated
 RockSim
estimated CP/CG locations
 On the unstable side
 Add mass to nose of rocket
11
Recovery Scheme
 Two
Separations
◦ Apogee
 Drogueless
◦ 500 Feet
 Main Parachute
 Double
Redundancy
◦ Flight computer
◦ Altimeter
500 Feet
Apogee
12
Vehicle Safety Verification Plan
This matrix shows
detrimental failures in
red, recoverable
failures in yellow, and
failures with a minimal
effect in green
13
Testing Plans
 Ground
test proper body tube separation
during E-Charge ignition
 Use
a multimeter to measure the current
the Flight Computer sends to each ECharge during ground simulations
 Servo
selection through torque testing on
flap from collected simulation/wind tunnel
data
14
Motor Selection
 Motor
Manufacturer:
Loki
 Motor Designation:L1482-SM
 Total Impulse:
868.7 lb-s
 Mass pre/post burn:
Pre:7.8 lb

Post:3.8 lb
15
Thrust-To-Weight Ratio
16
Rail Exit Velocity
 Rail
Exit Velocity: 85.1 ft/s
 Rail Length:
10 ft
17
Recovery Avionics









Raven Flight Computer
Competition Altimeter
4 Total E-Charges
2 from Flight Computer
2 from Altimeter
1
◦
1
1
◦
1
Main Apogee Charge
@ 5280 feet
Backup
Main Chute Charge
@ 400 feet
Backup
Apogee TB
9V Batteries
AvBay
Flight
Computer
Competition
Altimeter
Positive TB
Main Chute
TB
18
Aerodynamics-Linear Flaps: i.
 Flap
Geometry
 0% closed corresponds to the position
where the flap is not exposed to air flow
 100% closed corresponds to where the flap
is fully extended into the flow
Flap Max % Closed
A
100
Flap End
Geometry
Semi-Circle
Can Inner Dia
[in]
1.504
Flap Width [in]
B
100
Semi-Circle
2.551
2.551
C
65
Rectangular
2.551
2.551
D
75
Rectangular
2.551
2.051
1.504
19
Aerodynamics-Linear Flaps: ii.
Flap A
Flap B
20
Aerodynamics-Linear Flaps: iii.
Flap C
Flap D
21
Aerodynamics-Linear Flaps: iv.
 Drag
data from cases run at 300 m/s
Flap
A
B
C
D
Maximum Drag [N]
81.7235
240.396
204.086
197.838
*NOTE: All flap data is for one flap and all rocket data is for half-body
22
Aerodynamics-Rotating Flaps: i.
 Moment
Concerns with the y component of
the force generated by the flap at various
angles
 Analyzed at the most extreme case (largest
can and flap size at 45 ̊)
 Force in the y direction caused by the flap
angle deflection is negated by the force it
creates on the wall of the can
Component
Rocket
Force in y-direction [N]
-199.8
Flap
199.61
*NOTE: All data is from a simulated wind speed of 300 m/s
23
Aerodynamics-Rotating Flaps: ii.
ANSYS Fluent CFD mesh
sizes were refined in areas
of interest such as the flap
and the interior wall for
optimal results.
24
Structures-Can Analysis
 Analyzed
the worst case scenario (flaps
100% closed)
 Pressure forces in front of the valve are
not a concern
 Low pressure pockets behind the valve are
not a concern
25
Controls: i.
 Proportional
Integral Derivative (PID)
controller that will induce pressure drag as
a means of regulating vehicle altitude
 Drag is calculated dynamically during flight
 Controller should respond to physical
system changes in no more than 50
milliseconds and recover within 2% of the
goal altitude
26
Controls-System Model: ii.
Dynamic Apogee-Rectifying Targeting (DART) Control System
Dynamic Target: Used to aid in assuring the mean energy path solution is
followed
Restrained Controller: Proportional Integral Derivative (PID) derived
controller with physical limits
Physics Plant: Simulation of vehicle-environment interaction given controller
commands
Instrument Uncertainty: Propagation of instrument uncertainty into system
values
Alt. Projection: Projection of rocket apogee altitude with same physics plant
model for consistency
27
Controls – Dynamic Target
Controls – Restrained Controller
Controls - Physics
Controls –Instrument Uncertainty
Controls – Apogee Calculation
Flight Avionics

Drag Servo
Competition Altimeter

Drag Computer

Drag Servo
9V Batteries
Drag
Computer
Competition
Altimeter
33
Propulsion
 Select
a motor such that it will allow our
rocket to exceed one mile in our minimum
drag configuration
34
Payload Design
Drag Control System
Actuating flaps
located within side
cans to control drag
Control system will
activate under
specific altitude
and/or velocity
conditions
35
Payload Test Plan i.
Flap
Drag Testing
Simulations/flow characterization using
compressible flow in ANSYS Fluent CFD over
a range of Mach numbers
Test drag flap mechanism in various
configurations to confirm results from
simulated model
Produce a function for control system
relative to drag, flow speed and flap
deflection
36
Payload Test Plan ii.
Drag Flap Control System Testing
 4 constants to vary (Kp, Ki, Kd, Dt)
 N^4 simulations for N possible different
constants
 Parallel processing in Matlab to tackle
Monte Carlo simulation
 NYX / FLUX supercomputers from UM
Center for Advance Computing used to
tune constants for best performance
37