1. DE/kv 12/1/03 AES Technology Centers of Excellence Organic Air Vehicle (OAV) Flight Control An Application of Multi-Application Control (MACH) Dale Enns Honeywell 4 March 2005 SAE AEROSPACE CONTROL AND GUIDANCE SYSTEMS COMMITTEE Salt Lake City, Utah

2. DE/kv 12/2/03 AES Technology Centers of Excellence Introduction Takeoff, ascend, hover, rotate, translate, descend, land autonomously and with pilot in the loop MissionsVehicle

3. DE/kv 12/2/03 AES Technology Centers of Excellence Design Theory l True Aircraft Model (TRAC) l Controlled Variable (CV) l Calculus and On-board Aircraft Model (OBAC) l Dynamic Inversion l Feedback Controls x = States incl. p, q, r, u, v, w, … u = Control Surfaces y = p, q, r x x x x x x X TRAC OBAC C K a(x) f(x,u)h(x) xyu

4. DE/kv 12/2/03 AES Technology Centers of Excellence Basic Feedback Loop l Proportional Gain = l Integral Gain = l Command Gain = l Anti-Integral Windup Gain = l Closed Loop Transfer Function = l Loop Transfer Function (at y) = _ _ _

5. DE/kv 12/2/03 AES Technology Centers of Excellence Heading Command Position Commands Velocity Commands Attitude Commands Angular Rate Commands Vane Commands Throttle Command Inner loop pair Outer loop pair Control Law Structure

6. DE/kv 12/2/03 AES Technology Centers of Excellence Control Allocation Approach Given B and d find u to minimize || Bu – d || 2 Subject to constraints u min < u < u max u1u1 u2u2 d1d1 d2d2 d = B u Constraints include worst case of Position and rate limits Solution involves finding the intersection of two ellipsoids Desired d is unachievable so find Closest approximation with axis prioritization

7. DE/kv 12/2/03 AES Technology Centers of Excellence Unique Inverse l Montontonicity for scalars l Example for 2 dimensions We require that the Jacobian not change sign over the region of interest Jacobian = Such that the solution to has a unique solution for a given d Solution 1Solution 2 Jacobian > 0Jacobian < 0 f (u) d u

8. DE/kv 12/2/03 AES Technology Centers of Excellence 2x2 Example of Non-Unique Inverse In Quadrant 1 f 1 = u 1 + 3/2 u 2 f 2 = 1/3 u 1 + u 2 In Quadrant 2 f 1 = u 1 + 3/2 u 2 f 2 = u 1 + u 2 In Quadrant 3 f 1 = u 1 + 1/2 u 2 f 2 = u 1 + u 2 In Quadrant 4 f 1 = u 1 + 1/2 u 2 f 2 = 1/3 u 1 + u 2 f(u) is piecewise linear, continuous Slopes of diagonal are equal to 1 Off-diagonal slopes change at the origin Mapping of -2 < u 1 < 2 -2 < u 2 < 2 Jacobian = 1/2 Jacobian = -1/2 Jacobian = 1/2 Jacobian = 5/6

9. DE/kv 12/2/03 AES Technology Centers of Excellence Closed Loop Poles = Open Loop Zeros Open Loop Dynamic Inversion Closed Loop for Theorem

10. DE/kv 12/2/03 AES Technology Centers of Excellence OAV Integrated Avionics – AV2 FMU WOW Magnetometer Altimeter Air Data A/D Engine Speed Temperature Battery State x-axis y-axis z-axis 1 2 6 5 8 3 7 4 Servo 3 Servo 4 Servo 1 Servo 2 Engine Throttle IMU +5V +V GND +5V GND GPS Rcvr +3.3V GND +15V-15V +5V Interim Radio Receiver µHard Modem Base Station CMOS Camera InfraRed Camera Serial FMU H/W External H/W Payload H/W Comm. H/W Serial 2.4GHz Video Transmitter Engine Temp I2C Serial PWM Pulse Train Serial

11. DE/kv 12/2/03 AES Technology Centers of Excellence OAV Avionics IMU FMU l Flight Management Unit –MEMS IMU HG-1900 –GPS –Blended GPS/Inertial Nav & Attitude information –Flight Control Laws –Actuation commands F Flight Control Surfaces F Engine Throttle –Payload selection –Payload pointing l Commonality of hardware leads to lower cost - common gun-launched IMU entering high volume production Honeywell Intl. Proprietary

12. DE/kv 12/2/03 AES Technology Centers of Excellence Flight Controls Adverse Weather Issues l Hover in steady wind –Vehicle will tilt into the wind –More tilt for more wind l Gusting winds –Vehicle will tilt back and forth to adjust to changing wind –Non-minimum phase response l Measurements of airspeed relative to vehicle lead to improved performance –Direct sensing –Estimation –3 components of relative wind

13. DE/kv 12/2/03 AES Technology Centers of Excellence Hover in Steady Wind  Tilt from Vertical Force Balance Moment Balance T L D mg Duct Nose Up Vanes Nose Down 10 203040 Pitch Axis Roll Axis Vane Deflection for Trim (Degrees) Horizontal Wind Speed (Knots) Large Roll Vane Deflection Required for Trim at Intermediate Speeds Wind Wind Along aa ee

14. DE/kv 12/2/03 AES Technology Centers of Excellence OAV Specifics l On-board Aircraft Model (OBAC) –3 Forces and 3 Moments are Dependent Variables – –Combine table lookup and analytical expressions for forces and moments –Rigid body with propeller/engine momentum equations of motion l Wind Estimator Estimation Gains OBAC Measurements Modeled Accels Accels Wind Estimate

15. DE/kv 12/2/03 AES Technology Centers of Excellence Robust Stability Analysis K M Satisfactory Negotiable Unacceptable log 10 0 Introduce Multiplicative Perturbations at all interfaces between Plant & Control Law _ Plant

16. DE/kv 12/2/03 AES Technology Centers of Excellence MOVIE OF OAV FLIGHT TEST 1 July 2004 Ft. Benning, Georgia

17. DE/kv 12/2/03 AES Technology Centers of Excellence Conclusions l Multi-Application Control (MACH) –Reusable control law –Robust, versatile, modular, nonlinear, multivariable design l Other Applications of Dynamic Inversion –X-35 Lockheed Martin Joint Strike Fighter –X-38 Prototype Crew Return Vehicle