Presentation given during ICRA 2013 to accompany the following paper: C. Papachristos, K. Alexis, A. Tzes “Model Predictive Hovering-Translation Control of an Unmanned Tri-TiltRotor”, IEEE International Conference on Robotics and Automation, ICRA 2013, Karlsruhe, Germany

1. University of Patras
Laboratory of
Automation & Robotics
ETH Zurich
Autonomous
Systems Lab
Christos Papachristos Kostas Alexis
University of Patras
Laboratory of
Automation & Robotics
Anthony Tzes
C. Papachristos, K. Alexis, A. Tzes

2. C. Papachristos, K. Alexis, A. Tzes

3. The multitude & increased demands of modern applications impose
the design of specialized vehicles
Monitoring & Surveillance
 Monitoring of wildfire breakouts
 over forested areas
 Continuous & uninhibited monitoring
 in populated areas
 Border interdiction detection
Assistance provision
 Missions in hazardous locations
 (e.g. Nuclear Reactors inspection)
 Search & Assist missions
 Aerial Photography & Mapping
 for Civilian & Civil Engineering
 Applications
C. Papachristos, K. Alexis, A. Tzes

4. Reconfigurable Aircraft
for
Flight-Mode Conversion
Fixed-Wing Aircraft
 High-Speed Flight
 Endurance
VTOL Rotorcraft
 Vertical Flight
 High-Precision
Maneuvers
C. Papachristos, K. Alexis, A. Tzes

5. Rigid-Body Dynamics
Newton-Euler Formulation
Roll
Pitch
Yaw
Longitudinal
Lateral
Vertical
Actuation Subsystem Dynamics
–
Frequency Domain Identification
Augmented Linear Model around Hovering
Compact Representation of Rigid-Body + Actuator Dynamics
Generalized Hovering Operating Point
Actuators Control Inputs
Rigid-Body States (Rotation & Translation)
Actuator States (Rotors Thrust & Angles)
C. Papachristos, K. Alexis, A. Tzes

6.  1.6 GHz Atom MCU
 Cortex-M3 ARM
 100 Hz AHRS
 Sonar
 Optic Flow Camera
 Rotor RPM Encoders
 High-Update Rate ESCs
 800 W Main Motors
 High-Torque Servos
 Ubuntu Linux OS
 Matlab Real-Time
 Workshop
 OpenCV
Specifications
Software
Mechanical
 CAD-based Design
C. Papachristos, K. Alexis, A. Tzes

7. State Estimation – Control Computation – Communications
Control Computation
AHRS
Measurements
Low-Level Interfacing
Almost Real-Time
Execution Control
Wireless
Communications
Vision - Optical Flow
Camera Model-based
Rotation-Compensated
Translational States Estimation
Optical Flow + IMU
C. Papachristos, K. Alexis, A. Tzes

8. Attitude Controller: Gain-Scheduled P-D-dD
Roll Tracking Response
&
FD-Identified Closed-Loop Roll Model
Translation Controller: Constrained Model Predictive Control
State, State setpoint
Control Input Move Input, Input
Setpoint
Gain Scheduling provides
Improved Tracking Response
Without Violating Constraints:
State & Control Input Constraints
accounting for limitations based on
dynamics & mechanical limitations
of the UAV (i.e. Adverse Reaction
Moment during Rotor-Tilting)
C. Papachristos, K. Alexis, A. Tzes

9. Translation External DisturbanceTranslation Step Reference
3D-Trajectories
C. Papachristos, K. Alexis, A. Tzes

10. Hovering Setpoint
Go-and-Return
Maneuvers
Z – step
Y – step
X – step
By employing Rotor-
Tilting
Faster Longitudinal
Dynamics
are Achieved
Video Results corresponding to Illustrated Datasets
C. Papachristos, K. Alexis, A. Tzes

11. Current Work: Exploitation of Yet-Unexplored Capabilities of Reconfigurable UAVs
Mock-Up: Desired UAV Path: Heavy Obstacle Blocking Doorway Entrance
Rotor-Tilting
gives
Full Longitudinal
Actuation
C. Papachristos, K. Alexis, A. Tzes
Push
Heavy Obstacle
(5kg)
Aside

12. Christos Papachristos
papachric@ece.upatras.gr
Kostas Alexis
konstantinos.alexis@mavt.ethz.ch
Anthony Tzes
tzes@ece.upatras.gr
C. Papachristos, K. Alexis, A. Tzes