Technical Articles and Newsletters

MATLAB and Simulink in the World: Medical Devices

In nearly 2000 medical device companies worldwide, engineers use MATLAB® and Simulink® to analyze image and signal data, design controls and signal processing algorithms, implement their designs in software after thorough verification and validation, and automatically generate reports for standards compliance.

Virginia Commonwealth University

Simulating cardiovascular conditions using a fully automated mock circulatory loop

Mock circulatory loops (MCLs) simulate the human circulatory system to enable testing of cardiac assist devices. When conducting tests using an MCL, investigators must adjust the settings on each component in the loop. VCU researchers modeled a fully automated MCL in which the mechanical pump, compliance chamber, and peripheral resistance valve settings are dynamically adjusted via microprocessors. The complete Simulink model of the system enables the user to apply parameter estimation routines to patient data to determine the settings needed to replicate a wide range of cardiac conditions and dynamics.

Cleveland FES Center and Case Western Reserve

Restoring movement to paralyzed limbs with functional electrical stimulation

For individuals with neurological impairments, functional electrical stimulation (FES) can help make real what was once only imagined: the restoration of movement to paralyzed arms and legs. FES devices send electrical impulses to electrodes—implanted in the body, worn on the skin, or operating through the skin—to produce and control movement. Researchers at Case Western Reserve University developed a flexible, configurable system technology platform that enables rehabilitation engineers to change an FES controller in the clinic and build FES control software. The Simulink based Universal External Control Unit enables clinicians to develop and refine their own FES applications up to 10 times faster than before.

Cochlear Limited

Streamlining development of cochlear implant sound processing algorithms

Noise reduction algorithms help cochlear implant recipients perceive speech in challenging acoustic settings. Engineers at Cochlear use Simulink to model and simulate candidate algorithms. After identifying a promising algorithm, the engineers generate C code from the model using Simulink Coder™. The code is compiled and deployed to a Speedgoat turnkey real-time system with Simulink Real-Time™. In clinical validations, the Simulink Real-Time system is linked via custom hardware to a recipient’s implant, enabling the clinician to measure the performance of the algorithm using simulated real-life acoustic conditions, including live speech in quiet and noisy environments.


Accelerating FPGA development of an intravascular imaging system

A patient with lipid core plaques (LCP) is vulnerable to coronary artery disease, the number one killer in developed countries. Infraredx developed the only FDA-approved medical device for LCP detection. The TVC Imaging System™ combines near-infrared spectroscopy with intravascular ultrasound (IVUS) in a single coronary catheter to provide information about vessel composition and structure. Infraredx engineers modeled and simulated the IVUS signal and image processing algorithms in Simulink, and implemented the design on the Altera® Cyclone FPGA using VHDL® code generated from the Simulink model with HDL Coder™. The generated HDL used the same number of multipliers as their handwritten HDL while using 9% less logic and 3% less memory.

ITK Engineering

Developing IEC 62304–compliant controller software for a dental drill motor

Sensorless brushless DC (BLDC) motors cause less abrasion than brushed motors, and are more reliable, quieter, and easier to maintain, but they require complex control algorithms. ITK Engineering developed a production BLDC motor controller that complies with the IEC 62304 medical device software standard. They modeled the motor, including its electrical and mechanical components, in Simulink. They developed a Simulink controller model, and used Stateflow® to model startup, shutdown, and error modes, as well as user-selectable operating modes. After running closed-loop simulations of the plant and the controller, they generated more than 5000 lines of C code from their controller model, and compiled the code for an ARM® Cortex®-M3 processor.

University of Pennsylvania

Closed-loop real-time testing of pacemakers with virtual heart models

One-third of the more than 600,000 cardiac medical device recalls that occurred between 1990 and 2000 were due to software problems. To enable early verification of pacemaker software, University of Pennsylvania engineers developed a first-of-its-kind heart-on-a-chip that can be configured to match a patient’s specific electrophysiological characteristics. The team built an electrophysiological model of the heart in Simulink and Stateflow, and deployed multiple versions of the heart model on an Altera FPGA using automatically generated HDL code. Using the virtual heart model running on the FPGA in real time they simulated several closed-loop scenarios, including pacemaker-mediated tachycardia and atrial flutter, as well as failure conditions, such as a displaced pacemaker lead.

Published 2014 - 92204v00