The Tongue Drive System

Published Date: 02 Nov 2017

Abstract—we have developed a wireless, noncontact, unobtrusive, tongue-operated assistive Technology called the Tongue Drive System (TDS). The TDS provides people with minimal or no movement ability in their upper limbs with an efficacious tool for environmental control. A small magnet secured on the tongue by implantation, piercing, or tissue adhesives is used as a tracer, the movement of which is detected by an array of magnetic field sensors mounted on a headset outside the mouth or on an orthodontic brace inside. Our ultimate goal in developing the TDS is to help people with severe disabilities experience and preserve an independent, self-supportive life. The tongue movements can then be translated into various commands for environment control. To operate the Tongue Drive system, potential users only need to be able to move their tongues. We chose the tongue to operate the wheelchair, which are controlled by the brain through the spinal cord, the tongue is directly connected to the brain by a cranial nerve that generally escapes damage in severe spinal cord injuries or neuromuscular diseases. Tongue movements are also fast, accurate and do not require much thinking, concentration or effort.

Keywords— Assistive technologies, environment control, field sensors.

Introduction

Persons severely disabled as a result of causes ranging from traumatic brain and spinal cord injuries (SCI) to amyotrophic lateral sclerosis (ALS) and stroke generally find it extremely difficult to carry out everyday tasks without continuous help. In the U.S. alone, 11 000 cases of severe SCI add every year to a population of a quarter of a million as a result of acts of violence, falls, and accidents. Fifty-five percent of the SCI victims are between 16 and 30 years old, who will need lifelong special care that currently cost $4 billion each year. Assistive technologies (ATs) help individuals with severe disabilities communicate their intentions to others and effectively control their environments. These technologies would not only ease the individuals’ need for receiving continuous help, thus reducing the burden on family members, releasing a dedicated caregiver, and reducing their healthcare and assisted-living costs, but may also help them to be employed and experience active, independent, self-supportive, and productive lives, equal to the other members of the society. Despite the wide variety of existing ATs for individuals with lower levels of disabilities, those with severe disabilities are still considered underserved, and would greatly benefit from having more choices, especially in utilizing ATs that can take advantage of whatever remaining capabilities they might have.

A number of ATs have been developed in the past for helping individuals with severe disabilities control their environments by discerning the individual’s intention and directly communicating it to a computer that plays the role of an interface between the user and his/her intended target, such as a powered wheelchair (PWC). It is not hard to imagine that once paralyzed individuals are "enabled" to effectively use computers, they will have access to all the opportunities that able-bodied individual may have through using computers. It is well known that cranial nerves, which are protected by the skull, often escape injuries even in severe cases of the SCI. Many of these nerves are not afflicted by neuromuscular diseases either. Hence, those parts of the body which are innervated by the cranial motor nerves, such as eyes, jaws, facial muscles, and tongue, are good candidates to be employed for discerning users’ intentions as intermediate links to the brain. A major advantage of these ATs is that they can be non-invasive and potentially benefit a large population of individuals with different levels of disabilities. Tongue and mouth occupy an amount of sensory and motor cortex in the human brain that rivals that of the fingers and the hand. Therefore, they are inherently capable of sophisticated motor control and manipulation tasks with many degrees of freedom (DoF). The tongue muscle is similar to the heart muscle in that its rate of perceived exertion is very low and it does not fatigue easily. The tongue is noninvasively accessible and is not influenced by the position of the rest of the body, which can be adjusted for maximum user comfort. The above reasons have resulted in development of a number of tongue-computer interfaces (TCI) such as Tongue- Touch- Keypad (TTK), Tongue Mouse, Tongue Point, and a recent inductor- based system. These devices, however, require bulky components inside the mouth which may interfere with the user’s speech, ingestion, and sometime breathing. Our goal has been developing a minimally invasive, unobtrusive, easy to use, and reliable TDS that can substitute some of the arm and hand functions, which are perceived as the highest priorities among the individuals with severe disabilities. The TDS presented in this paper, called Tongue Drive, can wirelessly detect the tongue movements inside the oral cavity and translate them into a set of specific user-defined commands (tongue alphabet) without interfering with speech, ingestion, or breathing, and without the tongue touching anything. These commands can then be used to control the wheelchair and other devices in the user’s environment.

Ease of use

Testability

Testability is measure of how well system or component allows you to create test criteria and execute tests to determine if the criteria are met. Testability allow faults in a system to be isolated in a timely and effective manner

The key issues are:

Lack of test planning.

Start testing early during the development life cycle.

Supportbility

Supportability is the ability of the system to provide information helpful for identifying and resolving issue when it fails to work correctly.

The key issue for supportability is:

Lack of diagnostic information.

Identifying how you will monitor system activity and the performance such as Microsoft system centre.

System Implementation

User Interface

The user interface will be simple and consistent, using terminology commonly understood by the intended users of the system. The system will have a simple interface, consistent with industry standard interfaces, to eliminate the need for user training of infrequent users. The User testing will be used to ensure the user interface is clear (simple, commonly understood vocabulary, intuitive to use without training), complete (users can perform all functions from the interface), and consistent (buttons and wording are the same throughout the system)

Hardware Interface

The hardware interface in this system is basically interface card and parallel ports are used for communication between end-user (disable Person) and the hardware devices. The hardware devices such helical-gear motor and RF Transmitter-Receiver are controlled from the end-user system which signals the interface card through parallel port.

Software Interface

The system will use Microsoft.NET 2005 framework which is an open source, ASP.Net is used for designing web-application and VB.net is used for designing the drivers.

Communication Interface

In the propose system parallel port is used for communication

Parallel port provides advantage of transferring 8 data bit per I/O clock cycle.

On centenary serial port do not provide faster speed than parallel port.

At a time whole chunk of data is transfer thus increasing speed of operation.

Hence, Parallel port is chosen for data communication in

this system.

System Architecture

Following figure shows the external TDS-wheelchair wireless interface prototype, being used by one of the users. This prototype consists of a standard TDS headset, a permanent magnetic tracer attached to the user’s tongue, a wheelchair, a small RF module built in a wheelchair style connector (inset), and an application running on the wheelchair with a GUI customized for our current trial. In the following fig. 1. We have shown the system processing of the input signals in more detail.

Fig. 1. Processing of Input Signals

In the following fig. 2. We show the hardware component of the system and the operating system of the wheelchair with the help of relays.

Fig. 2. Circuit Diagram of TDS System

Advantages

It captures a wide variety of tongue movements.

In the human body our tongue is more flexible than other part of our body and there is direct connection between our tongue and brain through the cranial nerve so, it will capture more tongue movement.

It provides disabled people to have more freedom.

The ultimate goal to develop this kind of technology is to help disable people that they deserve an independent life. So, with the help of this disable person can control their own environment.

It is invasive.

Any instrument or equipment that we will use in this technology or the project is not harmful for human life. With that no any damages will occur to the human body so it is invasive.

Easy Signal Capturing

The signals from the magnetic sensors are linear functions the magnetic field, which is a Continuous position dependent property. Thus a few sensors are able to capture a wide variety of tongue movements.

Disadvantages

Computer battery could die when not around charger.

The head sensor can be affected due to external magnetic field

Conclusion

Tongue drive system technology is a gift for the physically challenged and disabled persons to lead their life equal to the normal persons in the society. A tongue operated magnetic sensor based wireless assistive technology has been developed for people with severe disabilities to lead a self-supportive independent life enabling them to control their environment using their tongue. This technology works by tracking movements of permanent magnet, secured on the tongue, utilizing an array of linear Hall- effect sensors.

The sensor outputs are a function of the position-dependent magnetic field generated by the permanent magnet. This allows a small array of sensors to capture a large number of tongue movements. Thus, providing quicker, smoother, and more convenient proportional control compared too many existing assistive technologies. Other advantages of the Tongue Drive system are being unobtrusive, low cost, minimally invasive, flexible, and easy to operate. A more advanced version with custom designed low-power electronics that entirely fit within the mouthpiece is currently under development.

Abbreviation and acronyms

TDS- Tongue Drive System

RF- Module- Radio Frequency Module

GUI- Graphical User Interface

SCI- Spinal cord injuries

ALS-Amyotrophic lateral sclerosis

ATs- Assistive technologies

PWC-Powered wheelchair

DOF- Degree of freedom

TCI- Tongue computer interfaces.

TTK- Tongue touch keypad.

Acknowledgment

We take this opportunity to thank our project guide Prof. P. A. Chaudhari and Head of the Department Prof. N. V. Alone for their valuable guidance and for providing all the necessary facilities, which were indispensable in the completion of this project. We also thankful to all the Staff members of the Department of Computer Engineering of Gokhale Education Society's R. H. Sapat College Of Engineering, Management Studies & Research, Nashik-5 for their valuable time, support, comments, suggestions and persuasion.

We would also like to thank the institute for providing the required facilities, Internet access and important books. At last we must express my sincere heartfelt gratitude to all staff members of Computer Engineering Department who helped us directly or indirectly during this course of work.