Most biomechanical systems involve some sort of motion or an action, which can range from the articulation of a large exoskeleton to the mechanical stimulation of the tiny bones in the middle ear. These actions are created by a force or torque that leads to acceleration and displacement. In most cases these actuators operate by the conversion of electrical power; however, in biomechatronics, pneumatic and hydraulic devices offer some advantages, discussed in this chapter. Electrical devices that produce or trigger a physical or physiological response by stimulating the body's musculature or nerves are also considered to be actuators. These include pacemakers, defibrillators, transcutaneous electrical nerve stimulation (TENS) devices, and other electrode arrays such as retinal, neural, or cochlear implants. They are discussed in other chapters in this book.

Chapter Contents:

• 3.1 Introduction
• 3.2 Electromechanical Actuators
• 3.2.1 Solenoids and Voice Coils
• 3.2.2 Direct Current Motors
• 3.2.3 Brushless DC Motors
• 3.2.4 Stepper Motors
• 3.2.5 Linear Actuators
• 3.2.6 Servo Motors
• 3.2.7 AC Motors
• 3.3 Hydraulic Actuators
• 3.4 Pneumatic Actuators
• 3.4.1 Pneumatic Muscles
• 3.5 Shape Memory Alloy
• 3.5.1 Principle of Operation
• 3.5.2 Biomechatronic Applications
• 3.6 Mechanical Amplification
• 3.6.1 Linkages and Levers
• 3.6.2 Cams
• 3.6.3 Gears and Belt Drives
• 3.6.4 Translation Screw Devices
• 3.7 Prosthetic Hand Actuation
• 3.7.1 Shape Memory Alloys
• 3.7.2 Electric Motors
• 3.7.3 Pneumatic Artificial Muscles
• 3.8 References

Inspec keywords: electromechanical actuators; hydraulic actuators; bone; mechatronics; ear; neuromuscular stimulation; pneumatic actuators; biomechanics

Other keywords: biomechatronics; exoskeleton articulation; mechanical stimulation; physiological response; pacemaker; defibrillator; bone; ear; actuator; pneumatic device; electrode array; transcutaneous electrical nerve stimulation; biomechanical system; hydraulic device; electrical power

Subjects: Hydraulic and pneumatic control equipment; Bioelectricity; Microactuators; Biomechanics, biorheology, biological fluid dynamics; Biological and medical control systems; Electrical activity in neurophysiological processes