Post on 01-Jan-2016
description
Digitally-Bypassed Transducers: Interfacing Digital Mockups to Real-
Time Medical EquipmentScott Sirowy*, Tony Givargis‡ and Frank
Vahid*‡
This work was supported in part by the National Science Foundation
*Department of Computer Science and Engineering
University of California, Riverside{ssirowy,vahid}@cs.ucr.edu
‡Center for Embedded Computer SystemsUniversity of California, Irvine
givargis@ics.uci.edu
Introduction: Medical Device SW Development
Matlab, MML, VisSim, etc
Lung
Ventilator
PC Simulation Simulate medical device
and physiological system completely in software
Supports rapid software changes, faster than real-time execution, and avoids potential safety concerns
Introduction: Medical Device SW Development
Physical Mockups Later in development, migrate
simulated physiological models to physical models
Used when medical device software is running on actual hardware
Potential inability to adapt to new features
Introduction: Medical Device SW Development
Digital Mockups Combines the benefits of faster than real-time
execution of simulation with advantages of developing software on real device
Potentially cheaper than physical mockups too
Matlab, MML, VisSim, etc
Lung
Ventilator
PC Simulation Physical Mockups
(Flexibility, speed, no real hardware) (Real Hardware, more realistic, costly, some scenarios difficult to model )
Introduction: Medical Device SW Development
PC Simulation Supports rapid software changes, faster than real-time
execution, and avoids potential safety concerns
Physical Mockups Used when medical device software is running on actual
hardware Potential inability to adapt to new features
Digital Mockups Combines the benefits of faster than real-time execution of
simulation with advantages of developing software on real device
Potentially cheaper than physical mockups too
Introduction: Medical Device SW DevelopmentPhysical Mockups
Ventilator Physical Lungs Mockup
SW Core
Physical Tube
TransducersPressure and Volume Sensors
Introduction: Medical Device SW DevelopmentDigital Mockups
Ventilator Digital Lungs Mockup
SW Core
Left Unconnected
Digital Interface
Digital MockupsDigitally-Bypassed Transducers
Medical Device Digital Mockup
SW Core
Output 1Input 1
(Digital)SensedInput …
Input n Output n
SensedInput
(Digital)
(Digital)
(Digital)
Control/Synchronization Channel
Input 1
…
Physical Value
Physical ValueInput n
Output 1
= Digitally-bypassed Transducer
Output n
Digital Bypass
Digital MockupsDigitally-Bypassed Transducers
Transducer
Digital input
Sensed Value
Bypass Transducer
(to medical device)
Digital output
Input Digitally-Bypassed Transducer Output Digitally-Bypassed Transducer
Transducer
Digital output
Physical Value
Digital input
(from medical device)
Simple and inexpensive hardware additions enable bypassing the transducer inputs and outputs, and enable working completely in the digital domain
Digital MockupsMedical Device-Digital Mockup Synchronization
Rate Synchronization: Dedicated Control/Synchronization Channel used to exchange connectivity information, sampling rates, and mockup execution speeds
Step 1: On initial connection, digital connectivity handshake
Step 2: Medical device sends required sampling rate
Step 3: Medical device and Digital Mockup agree on execution speed (real time, 2X faster, etc)
Step 4: Begin Execution
Medical Device Digital Mockup Step 1
Step 2
Step 3
Step 4
All communication done on the bi-directional control/synchronization channel
Medical Software Development with Digitally-Bypassed Transducers
Ventilator
SW Core
Ventilator
SW Core
Ventilator
SW Core
Digital Lungs Mockup
Digital Lungs Mockup
1) All Digitally-Bypassed Transducers
2) Combined Digital and Transducers
3) Full Interaction withPhysical System
TubePhysical Interface
Digitally-Bypassed TransducersEarly Prototype
Medical Device (Pacemaker)
Digital Mockup of a Heart
Control/Synchronization Channel
Digital Inputs/Outputs
Open leads for real physical analog connections
Transducers
Medical Software DevelopmentPrototype Results
Heart Digital Mockup and Pacemaker Implemented both pacemaker model
and digital model using a number of off-the-shelf microcontrollers
Digital Mockup based off a simple physical heart model
Able to test pacemaker in real-time, and faster and slower than real time
Medical Software DevelopmentPrototype Results
Lung Digital Mockup and Ventilator Lung Mockup Ventilator based off of
models from the NSR Physiome Projects
Plan on augmenting a real ventilator with digitally-bypassed transducers in the near future
Conclusions With a small amount of hardware
and software additions, we introduced the digitally-bypassed transducer Digitally-bypassed transducers enable
interfacing to digital mockups, enable medical software development at faster than real-time execution while still developing software on the real medical device