Vehicle Dynamics
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12-14 Nov.
CAD courtesy of Kelly Klima
2001 Conference on Cooperative Control and Optimization
9
Project Structure
Vehicle(s)
Planning Group M-ship NTG User Interface
2001 Conference on Cooperative Control and Optimization
6
Current Physical Layout
Vision PC Command & Control PC dSPACE card Programmable Interrupt Controller (PIC) Trainer Port Cable RC Transmitter
• • • • A number of wireless vehicles Vision system (emulates GPS) Command system Inter-vehicle communication
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
12-14 Nov. 2001 Conference on Cooperative Control and Optimization 11
Camera Image
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
12
Vision Calibration
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
21
Preliminary Graph Theory Results
• Model information topology as a directed graph • Changes in interconnection affect stability of configuration • Nyquist-based criterion for formation stability
The Caltech Multi-Vehicle Wireless Testbed: Initial Implementation
Lars Cremean, Jason Meltzer, Ben Lee, Richard Murray
(In collaboration with Steven Low, Jason Hickey, Eric Klavins, Reza Olfati, Bill Dunbar and Dave van Gogh)
“
ref x,y
Kd Kθ
T
P
”
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
16
Initial data – Theta control
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
12-14 Nov. 2001 Conference on Cooperative Control and Optimization 1
Outline
• What is the Multi-Vehicle Wireless Testbed (MVWT)? • Implementation of closed-loop vehicle control • Preliminary control results • Extension to multiple vehicles • Conclusions and future work
Command Center
Simulation
Planning Group M-ship NTG
Vehicle Control Real-Time OS Onboard Onboard Comp. Comms. Vehicle HW
12-14 Nov.
Vehicle Control
Real-Time Monitor
12-14 Nov. 2001 Conference on Cooperative Control and Optimization 7
Future Physical Layout
Vision PC Command PC dSPACE card (optional) • Vision computer broadcasts states
12-14 Nov. 2001 Conference on Cooperative Control and Optimization 2
What is the MVWT?
• Experimental platform for investigating the intersection of control, computation and communications • Consists of:
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
14
Simulation Environment
• Dynamic simulation by Working Model 2D • DDE interface to MATLAB (and C/C++) for control design • Collision detection/ handling
17
Movie – Point-to-point automatic control
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
18
Data – Point-to-point automatic control
3
Prototype Vehicle Design
• Actuation: Two high-power unidirectional ducted fans • No onboard sensing • Receive fan input signals via radio link
12-14 Nov.
12-14 Nov.
δu
Local Control
2001 Conference on Cooperative Control and Optimization
20
Extension to Multiple Vehicles
• Currently two prototype vehicles built Eight next-generation vehicles planned • Each vehicle, in general, will have knowledge of the states of itself and some subset of all other vehicles
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
13
Vision Performance Specs
• 60 Hz • 16.8mm max. calibration error • 90% · 8mm • ~16msec latency
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
19
Trajectory Tracking Methodology
• • • • More general framework for control Compute feasible trajectory in real-time Compute associated inputs Control about nominal trajectory
Reference: Fax, Murray; Information Flow and Cooperative Control of Vehicle Formations, IFAC 2002 submitted
• Assuming linear friction acting at CoM ⇒ vehicle is linear in state, nonlinear in input • Input-constrained, underactuated (0· FS/P· Fmax)
12-14 Nov.
ref Trajectory Generation D Plant P
ud xd
noise
output
Reference: Milam, Mushambi, Murray, A Computational Approach to Real-Time Trajectory Generation for Constrained Mechanical Systems, CDC 2000
of all vehicles via wireless ethernet (UDP) • Command PC broadcasts individual or coordinated tasks • Each vehicle has own control and communication
12-14 Nov. 2001 Conference on Cooperative Control and Optimization 8
CAD courtesy of Kelly Klima
2001 Conference on Cooperative Control and Optimization
9
Project Structure
Vehicle(s)
Planning Group M-ship NTG User Interface
2001 Conference on Cooperative Control and Optimization
6
Current Physical Layout
Vision PC Command & Control PC dSPACE card Programmable Interrupt Controller (PIC) Trainer Port Cable RC Transmitter
• • • • A number of wireless vehicles Vision system (emulates GPS) Command system Inter-vehicle communication
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
12-14 Nov. 2001 Conference on Cooperative Control and Optimization 11
Camera Image
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
12
Vision Calibration
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
21
Preliminary Graph Theory Results
• Model information topology as a directed graph • Changes in interconnection affect stability of configuration • Nyquist-based criterion for formation stability
The Caltech Multi-Vehicle Wireless Testbed: Initial Implementation
Lars Cremean, Jason Meltzer, Ben Lee, Richard Murray
(In collaboration with Steven Low, Jason Hickey, Eric Klavins, Reza Olfati, Bill Dunbar and Dave van Gogh)
“
ref x,y
Kd Kθ
T
P
”
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
16
Initial data – Theta control
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
12-14 Nov. 2001 Conference on Cooperative Control and Optimization 1
Outline
• What is the Multi-Vehicle Wireless Testbed (MVWT)? • Implementation of closed-loop vehicle control • Preliminary control results • Extension to multiple vehicles • Conclusions and future work
Command Center
Simulation
Planning Group M-ship NTG
Vehicle Control Real-Time OS Onboard Onboard Comp. Comms. Vehicle HW
12-14 Nov.
Vehicle Control
Real-Time Monitor
12-14 Nov. 2001 Conference on Cooperative Control and Optimization 7
Future Physical Layout
Vision PC Command PC dSPACE card (optional) • Vision computer broadcasts states
12-14 Nov. 2001 Conference on Cooperative Control and Optimization 2
What is the MVWT?
• Experimental platform for investigating the intersection of control, computation and communications • Consists of:
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
14
Simulation Environment
• Dynamic simulation by Working Model 2D • DDE interface to MATLAB (and C/C++) for control design • Collision detection/ handling
17
Movie – Point-to-point automatic control
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
18
Data – Point-to-point automatic control
3
Prototype Vehicle Design
• Actuation: Two high-power unidirectional ducted fans • No onboard sensing • Receive fan input signals via radio link
12-14 Nov.
12-14 Nov.
δu
Local Control
2001 Conference on Cooperative Control and Optimization
20
Extension to Multiple Vehicles
• Currently two prototype vehicles built Eight next-generation vehicles planned • Each vehicle, in general, will have knowledge of the states of itself and some subset of all other vehicles
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
13
Vision Performance Specs
• 60 Hz • 16.8mm max. calibration error • 90% · 8mm • ~16msec latency
12-14 Nov.
2001 Conference on Cooperative Control and Optimization
19
Trajectory Tracking Methodology
• • • • More general framework for control Compute feasible trajectory in real-time Compute associated inputs Control about nominal trajectory
Reference: Fax, Murray; Information Flow and Cooperative Control of Vehicle Formations, IFAC 2002 submitted
• Assuming linear friction acting at CoM ⇒ vehicle is linear in state, nonlinear in input • Input-constrained, underactuated (0· FS/P· Fmax)
12-14 Nov.
ref Trajectory Generation D Plant P
ud xd
noise
output
Reference: Milam, Mushambi, Murray, A Computational Approach to Real-Time Trajectory Generation for Constrained Mechanical Systems, CDC 2000
of all vehicles via wireless ethernet (UDP) • Command PC broadcasts individual or coordinated tasks • Each vehicle has own control and communication
12-14 Nov. 2001 Conference on Cooperative Control and Optimization 8
