Aspects of Biomechatronics
Hearing and Balance
Mechatronic engineering can be defined as the synergistic combination of electronic, mechanical, control and computer systems. The application of mechatronic engineering in human biology is known as biomechatronics. It is a key area of study in biomedical engineering.
The components of biomechatronic systems are as follows:
- A human subject
- Sensors and transducers
- Signal processing systems
- Recording and display systems
- Feedback elements
These are explained in detail in the following sections.
A human subject – This subject represents the “bio” part of biomechatronics systems and makes these systems unpredictable due to their adaptability to a surrounding environment.
Stimulus – A stimulus is an input delivered naturally or mechanically to a feedback system. Common stimuli includes a tone, an electrical stimulus, tactile stimulus, a light source, or airflow.
Sensors and transducers – These are devices capable of transforming physiological outputs such as temperature or pressure into electrical signals.
Signal processing systems - They are generally used for modifying the electrical signal into an output signal that can be used in some way. This involves transforming analog signals to digital signals in order to apply complex algorithms.
Recording and display systems - A biomechatronic gadget is used to track a physiological process or a response, and then display and store the information in a user-friendly format for analysis and future use. An electrocardiograph is common example of a biomechatronic device.
Feedback elements - Processed sensor outputs can be connected to the stimulus by a feedback link, which can be further processed using control elements. This feedback loop is helpful in synchronization of the stimulus.
Biomechatronics can be used in the following applications:
- Bio-interfaces for diagnostics and control
- Robotics for high-speed screening and analysis
- Passive and active prosthetic limbs and joints
- Bio electrical signal processing
- Sensing and biofeedback
- Medical imaging and diagnostics
- Rehabilitation Systems
- Neural and brain stimulation
- Tele and robot assisted surgery
- Mobility aids
- Home care and elderly care
In future, biomechatronics can find applications in the following areas:
- Brain prostheses
- Autonomous hospital
- Memory down/upload
- Nano-machines and micro-robots
- Powered exoskeletons
- Hyper spectral vision – artificial eyes
- Pervasive neural interfaces
Aspects of Biomechatronics
Some key aspects of biomechatronics are given below:
- Hearing and Balance
These are explained in the following sections:
Hearing and Balance
Virtual reality can be used for stimulating the visual vestibular. A low cost and flexible system is built for determining the subject’s sway response to galvanic vestibular stimulation. The components of this system include the following:
- Electrical stimulator and electrodes
- Inertial measurement unit
- Nintendo Wii balance board
A handheld text reader and image pre-processing is utilized for performing optical character recognition (OCR). It is a device used in mobile phones for converting text into speech. It can be used for dewarping, interfacing to tesseract OCR, and enhancing poor illumination. The capability of a smartphone-based image processor can be evaluated for visual prosthesis.
Movements of eye and head are required to provide simulated prosthetic vision. Within a VR environment, two visual tasks should be carried out. The first task is identifying a room and the second task is finding an object in the room. Finally, the performance was assessed using different eye and head tracking combinations in order to move the visual mosaic.
A doppler SIDS monitoring system was used to reduce the occurrence of SIDS. A 24GHz doppler radar produces phase information, which can be used to read a baby’s breathing patterns. A mechanical lung simulator was used to simulate the lung in order to reduce sleep-disordered breathing. It requires programmable waveform, and is low in cost.
Chris Larkin developed an inexpensive fleisch pneumotachograph from low cost materials. It works based on Poiseuille’s law. A fleisch cell consists of 190 syringe needles.
Here, a myoelectric interface was used for controlling a robotic arm. A skin-surface electrode produced myoelectric signals that were sent to a myoelectric amplifier and signal conditioning hardware. Single-ended differential output was digitalized via GUI and C++ software. A control string was sent to RS 232 resulting in relaxed contraction, mid contraction and maximum contraction. The following video by NAIST(Nara Institute of Science and Technology, Graduate School of Information Science in Japan) Robotics Laboratory, is an example of the application of myoelectric interface for controlling a robotic hand.
A robotic orthotic device was developed for treating post stroke and other patients suffering from neurological damage. Finger sequences, fingers or whole hand can be subjected to the open loop exercise. Muscle strength was increased using programmable resistance force.
An assistive robotic power glove acts as an assistive orthotic for the human hand. This was used as a rehabilitation tool to restore functionality of the hand. It also helps the patients having low hand strength to carry out normal work in a simple manner.
After orthopaedic surgery, wireless monitoring devices are easily fixed in order to measure recovery of the knee. Two projects were performed in association with the Sydney Orthopaedic Research Institute. One is accelerometer and gyro-based measurement of shock absorption capability. Another one is Goniometer-based measurement of knee flexion and extension.
Accelerometer attachment method has two types of trials. One is five trials with sports tape, and another is five trials with sleeve. According to Clare Young, accelerometers can also be used for determining the functionality of the human knee.