Biomedical Engineering Reference
In-Depth Information
1.4
SUMMARY OF CONTENTS
Most biomechatronic systems operate by sensing some particular aspect of the environment
or the human body, processing the information, and then responding in some way. It is
therefore important that the student is aware of sensor technology, processing methods, and
actuation systems. These are all covered in the first half of this topic. Chapter 2 introduces
the concept of biometrics, the science of measuring physiological signals, and myriad
sensors that can be used to measure these. Such measurements include bioelectric signals
in the form of the electrocardiogram, the electroencephalogram, and the electromyogram.
Microphones can be used to measure heart sounds, while pressure and flow sensors measure
the characteristics of the cardiovascular and respiratory systems. Other sensors measure the
position and rates of limb elements, real and prosthetic. Chapter 3 considers various forms
of actuation that use electrics, hydraulics, or pneumatics. Chapter 4 closes the loop around
the measurement and actuation process. It examines various feedback types and methods
of analysis. Chapter 5 is the last of the background chapters, and it introduces concepts of
both analog and digital signal processing that are applicable to biomechatronic systems.
These include filtering in the analog and digital domains, rectification and detection of
signals, and sampling and digitization. It also introduces the reader to machine learning
algorithms, which are becoming important in improving our ability to interpret complex
physiological processes.
The second half of this topic is focused on specific aspects of human physiology with
respect to biomechatronic possibilities for their improvement or rehabilitation. Chapter 6
is concerned with hearing, and it considers conventional hearing aids, bone-anchored
hearing aid (BAHA) devices, middle ear implantable hearing devices (MEIHDs), as well
as cochlear and brainstem implants. Chapter 7 examines one of the less mature fields—
sensory substitution and ocular prosthetics based on neural and cortical implants. The
following three chapters address the rehabilitation or replacement of organs or systems
that move, with Chapter 8 focusing on the cardiovascular system, particularly in regard
to the total artificial heart and ventricular assist devices. Chapter 9 examines respiration
with a focus on negative pressure ventilators (iron lungs) and positive pressure respiration
devices. Finally, Chapter 10 examines powered and passive limb prostheses in detail, as
these are some of the most important biomechatronic devices.
1.5
THE FUTURE OF BIOMECHATRONIC
SYSTEMS
An introductory text cannot hope to cover even a small fraction of the biomechatronic
devices and systems that exist or will be available in the foreseeable future. This topic
provides some insight into the technology and applications that have been developed
over the last 60 years or so. But, as with all technology, the rate of advance in the field is
accelerating, so it is expected that some amazing new biomechatronic devices will become
available within the next decade.
Improvements in our ability to interface directly to the human neural system will
provide the greatest advances in a range of applications. Already, neural reinnervation
that offers both actuation and feedback is providing better interfaces to prosthetic limbs
(MacIsaac and Englehart, 2006; Kuiken, Miller et al., 2007). This is just an interim
measure, and direct interface to neurons in the brain will allow seamless integration of
