Biomechatronic Components

Orthotics vs. Prosthetics
Orthotic devices artificially assist human movement without replacing the impaired limb. In contrast, prosthetic devices replace the lost or injured limb to restore movement.

Why use biomechatronics rather than conventional orthotic/prosthetic devices? While many new orthotic/prosthetic devices use microelectronics and robotic components, they cannot accurately emulate the complex motions of human limbs. Current orthotic/prosthetic devices do not feedback to people or adjust to variable loads or complex terrains. They do not adjust on a moment-to-moment basis to the individual wearer. Biomechatronic devices promise to overcome these limitations by interfacing directly with the wearer's muscle and nervous systems to assist/restore motor control.

Any biomechatronic system must have the same types of components.:

Biosensors
Biosensors detect the user's "intentions." Depending upon the impairment and type of device, this information can come from the user's nervous and/or muscle system. The biosensor relates this information to a controller located either externally or inside the device itself, in the case of a prosthetic. Biosensors also feedback from the limb and actuator (such as the limb position and applied force) and relate this information to the controller or the user's nervous/muscle system.

Biosensors may be wires that detect electrical activity such as galvanic detectors (which detect an electric current produced by chemical means) on the skin, needle electrodes implanted in muscle, and/or solid-state electrode arrays with nerves growing through them.

Mechanical Sensors
Mechanical sensors measure information about the device (such as limb position, applied force and load) and relate to the biosensor and/or the controller. These are mechanical devices such as force meters and accelerometers.

Controller
The controller is interfaces the user's nerve or muscle system and the device. It relays and/or interprets intention commands from the user to the actuators of the device . It also relays and/or interprets feedback information from the mechanical and biosensors to the user. The controller also monitors and controls the movements of the biomechatronic device.

Actuator

Thank You
Thanks to Dr. Scott Bernstein for his assistance with this article,

The actuator is an artificial muscle that produces force or movement. The actuator can be a motor that aids or replaces the user's native muscle depending upon whether the device is orthotic or prosthetic.

See the animation below to view how the system works. Next, learn about the progress made in the field of biomechatronics.