Embed Size (px)
Citation preview
MATLAB AND CARDIOVASCULAR ENGINEERING
SOLVING PROBLEMS, SAVING TIME
Dr Michael Stevens
INNOVATIVE CARDIOVASCULAR ENGINEERING AND TECHNOLOGY LABORATORY
Using MATLAB in the ICET LAB
• Numerical Model (Computer Simulation)
• Mock Circulation Loop (Mechanical Simulation)
• Design and Tuning of Feedback Control Loops
1. Terracciano, C.M., L.W. Miller, and M.H. Yacoub, Contemporary use of ventricular assist devices. Annu. Rev. Med., 2010. 61: p. 255-70.2. Heidenreich, P.A., et al., Forecasting the Future of Cardiovascular Disease in the United States: A Policy Statement From the American Heart Association. Circulation, 2011. 123(8): p. 933-944.3. Thunberg, C.A., et al., Ventricular assist devices today and tomorrow. Journal of Cardiothoracic and Vascular Anesthesia, 2010. In Press.
• Prevalence: About 3% of population1,2
• Hospital admissions: Over 1M in US alone per year3
• Costs: $35B USD per year in US2
• Projections: $95B USD per year in US by 2030.2
• Less than 4000 heart transplants performed worldwide per year.
HEART FAILURE
Ventricular Assist Devices - VADs
• Bridge to transplantation
• Bridge to destination
Rise of VAD implantations
About The ICET LabThe Prince Charles Hospital
Combating cardiovascular disease by serving as a bridge between the engineering department and clinic.
ICET LAB - OUR AIM
Using MATLAB in the ICET LAB
• Numerical Model (Computer Simulation)
• Mock Circulation Loop (Mechanical Simulation)
• Design and Tuning of Feedback Control Loops
Testing VADs
High CostLow repeatabilityRequires proof of
concept
Low CostHigh repeatability
Numerical Model – Lumped Parameter Model
• Developed Dr Einly Lim – University of Malaya
Simulink Model – Cardiovascular System
• Created by PhD Student Frank Nestler
Simulink Model – Pump and Cannula
Validation – Left Ventricular Pressure
Literature Numerical Model
Using MATLAB in the ICET LAB
• Numerical Model (Computer Simulation)
• Mock Circulation Loop (Mechanical Simulation)
• Design and Tuning of Feedback Control Loops
Mock Circulation Loop
Instrumentation and Actuation
P
V
Q
PV
S&R
P
PP P
P
P
P
P
P
V
Q
Q
Q
PV
S&RS&R
16+ Analog inputs5+ Digital outputs7+ Analog OutputsControl @ 2000HzSample @ 100 Hz
S&R
S&R
Simulink Control Model for MCL
Controlling MCL with MATLAB and dSPACE
Simulink Model
dSpace Processor
Compile
DA out
AD in
Mock Circulation Loop In Action
MCL Validation Literature
MCL
Numerical Model
MCL Additions – Cerebral Circulation
Literature
Numerical Model
Using MATLAB in the ICET LAB
• Numerical Model (Computer Simulation)
• Mock Circulation Loop (Mechanical Simulation)
• Design and Tuning of Feedback Control Loops
Physiological Control:‘Smart’ Cruise Control for Rotary VADs
Automatically adjust speed to respond to physiological changes• Prevent collapse of ventricle
• Increase flow during exercise
Control System Tuning
• Very complex plant model
• High-order
• Non-linear
• Time and patient variance
• Tuning was performed using gradient descent optimisation.
• Initially developed own optimisation script
• Now use MATLAB Optimisation Toolbox
Optimisation Objective Function
Define Ideal Control + Plant
Behaviour
𝜔𝑛2
𝑠2 + 2ζ𝜔𝑛𝑠 + 𝜔𝑛2
+
- 0
𝑇Value to minimise
𝑥2
C(s) G(s)+-
Controller Plant
Target
Rise TimeSettling TimeOvershoot
Optimising to achieve an ideal response
Control Tuning using Optimisation: Some Considerations.
• Local vs. Global minima.
• Initial Guess of Gains.
• Requires careful selection of objective function and optimisation parameters.
• MATLAB documentation for Optimisation Toolbox very helpful.
Using MATLAB in the ICET LAB
• Numerical Model (Computer Simulation)
• Mock Circulation Loop (Mechanical Simulation)
• Design and Tuning of Feedback Control Loops
Solving Problems, saving time
Thank you
