Some people have limitations such that they could not proceed even a single step without the help of a wheelchair, and some are impaired such that they have limited upper body mobility. The powered wheelchair is a one-stop solution for all these problems since it can be customized according to the needs of every single individual.

A power wheelchair provides greater mobility and they are sophisticated wheelchairs that bring top-level comfort to the user. This type of wheelchair can be used outdoors, for long-distance travel or excursion, etc., The special features of a power wheelchair include power seat and tilt adjustments, leg rest, and backrest adjustments. These wheelchairs can be connected to other adaptive devices such as communication devices, computer access devices, respirators, and reclining seating systems. They are user-friendly for users who have severe mobility impairments.

Power wheelchairs are made up of three main components that are combined into a single system. They are

  1. The base
  2. The seating
  3. The driving mechanism

BASE

The basic types of bases are

  • Rear wheel drive – The real wheelbase has the power wheel facing toward the back of the chair. The real wheel drive chairs are easier to drive.
  • Front wheel drive – This is a rear wheel drive chair but can be flipped around. The power wheel is present in the front and this is a major advantage for getting over the obstacles.
  • Mid-wheel drive– The smallest turning radius is present in the mid-wheel drive chairs. This type is the predominant design in today’s market.

THE SEATING

The sky is the limit for seating arrangements in the power wheelchair. It is separated from the base and the armrests, leg-rests, back, cushion, etc., are chosen in such a way that suits the client/user. The power wheelchairs can be fitted with power tilt and seat elevators.

THE DRIVING MECHANISM

The joystick is used as the standard driving mechanism

The joystick is the common control interface between the user and the wheelchair. It produces voltage signals proportional to voltage, displacement, etc., For example, the farther the joystick is moved from the center, the faster the chair will go.

The various types of joysticks include

  • Displacement joysticks
    • They use potentiometers or optical sensors to convert the displacement to voltage
  • Inductive joysticks
    • They are the most common ones and are quite sensitive.
  • Force sensing joysticks
    • These joysticks use three basic transducers and rely on fluid pressure generally.
  • Beam-based force-sensing joysticks
    • These types of joysticks require negligible motion and so are used for people with limited motion abilities.

Mini joystick, Switch controls such as Head array and sip & puff systems are the alternate driving mechanisms.

SWITCH CONTROL

It simply uses a set of switches for controlling the wheelchair. The input of the user is latched by the controller and the wheelchair performs tasks according to the commands given. It is slower than joystick control and can be generated in many ways. Sip and puff and head array are the methods of switch control. These switches are mounted on armrests/lap tray for hand activation, or on the footrests for foot activation, or on the head rest for head activation.

INTEGRATED CONTROL

Integrated control facilitates the use of a single input device(e.g joystick) to control multiple actuators (e.g power wheelchair, environmental control unit, and manipulator) that helps the user for greater control over the environment.

M3S- Multiple Master Multiple Slave bus provides simple and reliable access for accessing a variety of assistive devices and this is based on CAN(Computer Area Network) standard.

POWER SYSTEM

Various types of motors are required to design the power wheelchairs. These wheelchairs use bi-directional drives without dynamic braking. The servo amplifiers used here employ PWM( Pulse width modulation).

So analyzing all these advantages and modern technologies implemented in a power wheelchair, is a greatly added power to the medical devices industry.

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