Development of a compact chin-operated force-sensing joystick

Abstract EN

Position sensing joysticks and switch arrays have been the traditional means of interface for chin control users of electric powered wheelchairs.

In this study, a force-sensing chin operated joystick has been developed as an alternative to these devices.

The important difference between a position sensing joystick and a force-sensing joystick is that the latter requires no range of motion, which may allow for easier, more comfortable chin control.

The mechanical design of the chin-controlled force-sensing joystick includes a base, force-sensing beam, covering case, and mounting bracket.

The electrical design is comprised of two strain gage bridges, two instrumentation amplifiers, Tattletale control board, and a digital to analog converter.

Software has been designed so that it determines the output characteristics.

The result is an output curve that allows for proportional control, limits maximum speeds, and creates a dead zone that corresponds to no motion of the wheelchair.

The software was able to change output characteristics to both a large and small degree without modifying the hardware.

This software flexibility allows for customization of performance characteristics such as asymmetric or symmetric force, adjustable force sensitivities, and filter tuning.