Bio-mechatronics is an applied interdisciplinary science that aims to integrate biology and mechatronics (electrical, electronics, and mechanical engineering). It also encompasses the fields of robotics and neuroscience. Biomechatronic devices cover a wide range of applications, from developing prosthetic limbs to engineering solutions concerning respiration, vision, and the cardiovascular system.

Bio-mechatronics mimics how the human body works. For example, four different steps must occur to lift the foot to walk. First, impulses from the brain's motor center are sent to the foot and leg muscles. Next, the nerve cells in the feet send information, providing feedback to the brain, enabling it to adjust the muscle groups or amount of force required to walk across the ground. Different amounts of energy are applied depending on the type of surface being walked across. The leg's muscle spindle nerve cells then sense and send the position of the floor back up to the brain. Finally, when the foot is raised to step, signals are sent to muscles in the leg and foot to set it down.

Biosensors detect what the user wants to do or their intentions and motions. In some devices, the information can is relayed by the user's nervous or muscle system. This information is related by the biosensor to a controller, which can be located inside or outside the biomechatronic device. In addition biosensors receive information about the limb position and force from the limb and actuator. Biosensors come in a variety of forms. They can be wires which detect electrical activity, needle electrodes implanted in muscles, and electrode arrays with nerves growing through them.

The purpose of the mechanical sensors is to measure information about the biomechatronic device and relate that information to the biosensor or controller. Additionally, many sensors are being used at schools, such as Case Western Reserve University, the University of Pittsburgh, Johns Hopkins University, among others, with the goal of recording physical stimuli and converting them to neural signals for a subarea of bio-mechatronics called neuro-mechatronics.

The controller in a biomechatronic device relays the user's intentions to the actuators. It also interprets feedback information to the user that comes from the biosensors and mechanical sensors. The other function of the controller is to control the biomechatronic device's movements.

The actuator can be an artificial muscle but it can be any part of the system which provides an outward effect based on the control input. For a mechanical actuator, its job is to produce force and movement. Depending on whether the device is orthotic or prosthetic the actuator can be a motor that assists or replaces the user's original muscle. Many such systems actually involve multiple actuators.

Bio-mechatronics is a rapidly growing field but as of now there are very few labs which conduct research. The Shirley Ryan AbilityLab (formerly the Rehabilitation Institute of Chicago), University of California at Berkeley, MIT, Stanford University, and University of Twente in the Netherlands are the researching leaders in bio-mechatronics. Three main areas are emphasized in the current research.

A great deal of analysis over human motion is needed because human movement is very complex. MIT and the University of Twente are both working to analyze these movements. They are doing this through a combination of computer models, camera systems, and electromyograms.