Design of a Contact Assistive Robot for the Disabled, Elderly, and Infirm People: Case for Developing Countries

Design of a Contact Assistive Robot for the Disabled, Elderly, and Infirm People: Case for Developing Countries

Tawanda Mushiri (University of Zimbabwe, Zimbabwe), Panashe Adrian Mombeyarara (University of Zimbabwe, Zimbabwe) and Thanks Marisa (University of Zimbabwe, Zimbabwe)
DOI: 10.4018/978-1-5225-9818-3.ch006


The use of a wheelchair for normal routines or rehabilitation has various physiological and psychological implications. The use of contact assistive robots in developing countries is limited mainly due to their expensive nature. The benefits of exoskeleton use include health improvement, increased self-dependency, and self-sustenance. The chapter offers a solution through the design of a cheap contact assistive robot for the disabled. The design procedure includes the integration of acquired knowledge on gait training and existing exoskeletons acquired from intense research, visits to rehabilitation centers, and use of computer-aided software for design and simulations. A fully functioning scaled prototype was made that demonstrated the operating principle of the actual design. The design provides a successful baseline for further development of exoskeletons suitable and cheaper for developing countries with an initial estimated total material cost of USD$9000.
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Throughout the years there has been significant progress in terms of improving the wheelchair to better accommodate the user in terms of comfort, mobility and less physical strain. However sitting in a wheelchair maybe comfortable for a few hours but having to sit during the whole day has very serious physical consequences. Health implications of using a wheelchair include muscle atrophy, osteoporosis, muscle spasms, cardiovascular disease (CVD), urinary tract infections (UTI’s) and varicose veins (Erikson, 2014). There are also psychological effects of being a wheelchair user such as low self-esteem, depression, denial, shock and stress but some of these effects can be overcome when the person is able to live an independent life with attributes such as being able to stand and walk freely (Taormina-Weiss, 2012) . When bound to a wheelchair, simple daily tasks get more challenging. Having to sit at a lower level compared to a standing person, reaching higher surfaces or hard to reach things like the bathroom or kitchen faucets become very challenging. On top of the height disadvantage, doorways might be too narrow for the wheelchair. Thibodeaux (2011) indicates that disabilities sometimes mean that an employee is not able to work at a pace comparable to other employees. For example, it may take longer for someone with a physical disability to move equipment, this sometimes makes a difference in jobs where the ability to keep pace affects other functions of the company, such as in a factory with an assembly line. However, it is not necessarily a disadvantage in other companies, such as an art restoration business where the quality, not the speed, of each project is more important. Considering the scenario for students, some academic programs may not be recommended to a student with a disability since they anticipate that their mobility will be problematic. The workplace and school campuses maybe physically accessible to a wheelchair user but it does not mean they are not barrier free.

Over the past few years companies in developed countries have produced contact assistive robots that are aimed at reducing the effects of wheelchair use. The companies include the Japanese based company Cyberdyne that produced the HAL exoskeleton series and Rex Bionics from New Zealand with the Rex. Some of these robots are already on the market while others are still on clinical tests and trials however for developing countries such robots are not available and even if they were, there would not be affordable for most of the people. The Rex has a buying price of around USD (United States Dollars) $100 000 which makes it almost impossible for people or the government to purchase them for the elderly, infirm and disabled people and whilst not forgetting to maintain them although according to recent studies the market for assistive robots in developing countries is expected to increase. This actually points out that there is need for developing countries to enter into the race of developing contact assistive robots for themselves that are cheaper, more suitable to them and as well as easy to maintain. The chapter therefore outlines the design of a contact assistive robot or exoskeleton that:

  • 1.

    Mimics the use of legs and easy to operate.

  • 2.

    Can be easily attached to the user and does not physically injure the user.

  • 3.

    Is easy to maintain with a rechargeable battery that works for approximately 2 hours of continuous normal use

  • 4.

    Is cost effective for users in developing areas

The motivation of the chapter lies on the need to reduce the effects of disabilities, increase mobility and self-sustenance of the disabled (paraplegic), infirm and elderly people. The exoskeleton will need to be cost effective so that its application can venture into the rehabilitation centres thereby making the entire rehab process more efficient and cheaper. Above all the chapter is in line with the sustainable development goals mainly goal 3 that focus on healthy lives and promoting well-being for all at all ages. The ability to be upright and to walk about in two limbs is a vital and basic characteristic of a human being and this skill is both a natural and important requirement for enhancing the quality of life.

Key Terms in this Chapter

Developed Country: A sovereign state that has a highly developed economy and advanced technological infrastructure relative to other less industrialized nations.

Detent Torque: A stepper motor's detent torque is the amount of torque the motor produces when the windings are not energized. The effect of detent torque can be felt when moving the motor shaft by hand, in the form of torque pulsations or cogging.

Cardiovascular Disease (CVD): A term generally referring to conditions that involve narrowed or blocked blood vessels that can lead to a heart attack, chest pain (angina) or stroke.

Muscle Atrophy: A condition in which the tissues in the muscles start to weaken and waste away. This can occur as a result of lack of muscle use, malnutrition, disease, or injury.

Holding Torque: A stepper motor’s holding torque is the amount of torque needed in order to move the motor one full step when the windings are energized but the rotor is stationary.

Osteoporosis: A medical condition in which the bones become brittle and fragile from loss of tissue.

Gait: A person's manner of walking.

Varicose Veins: Veins that have become enlarged and twisted. The term commonly refers to the veins on the leg, although varicose veins can occur elsewhere. Veins have pairs of leaflet valves to prevent blood from flowing backwards (retrograde flow or venous reflux).

Contact-Assistive Robots: Robots that provide assistance to people through physical contact or perform physical tasks for the well-being of a person with a disability. The tasks are embedded in the context of normal human activities of daily living (ADLs). They are popularly referred to as exoskeletons or Exo in short.

Muscle Spasms: A sudden involuntary contractions of skeletal muscles which are often due to overuse and muscle fatigue, dehydration, and electrolyte abnormalities.

Developing Country: A country having a standard of living or level of industrial production well below that possible with financial or technical aid; a country that is not yet highly industrialized.

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