Michael Dzura and I have been working for quite a while now in the development of strategies that would allow users of power wheelchairs (and others) to access and control complex devices (including MOR-PLAY).
Michael developed a neat strategy for navigating multidimensional spaces that could be eventually used to control a robotic or prosthetic arm using a single switch! (i.e. a single binary control) I have used Blender (an open source software for 3-D modelling and animation) to create a simulation that allows positioning a virtual pointer in a 3-D space using only the mouse left button. You can download the blender file here.
The idea behind this is to allow the user to navigate a type of cursor or pointer to a specific target just by using one switch. To illustrate this, an easy example would be moving a mouse pointer on the screen. To do so, a series of directions and functions can be cycled through. The first direction would be “UP”. This would be activated by pressing and holding the button. Soon as the button is released the direction would stop. Apply this theory to other directions and functions but have them cycled in whatever order that is the fastest and easiest for the user. You should now have a good fast reliable method of user control.
Michael’s Strategy can be used in conjunction with an inverse kinematics algorithm to control, for instance, the end point of a robotic arm with multiple joints. The user would be in direct control and no artificial sensory feedback (e.g. graphical user interface) is required.