Traditional control of complex mechanical or other controlled systems has been through the use of direct mechanical connections between a control input and the controlled system component.  For example, steering wheels mechanically connected to the wheels of a car have been used for controlling the steering of the car.  As a further example, pedals have been used for controlling car speed and braking.  As still further examples, joysticks have been used for controlling aircraft ailerons and elevators, and levers have been used for controlling aircraft engine power, etc.  These traditional control mechanisms are effective, but require the operator to have relatively full physical capabilities.  In addition, the need to provide room for such inputs and their associated connections limit cockpit design options. 
More recently, “fly by wire” type systems have been developed.  Such systems replace mechanical connections between the input and the control mechanism with electronic communication channels.  Such systems can provide increased flexibility in the packaging of the control systems.  In addition, such systems can facilitate the application of filters and other overlays on control inputs provided by a user, and can also facilitate the integration of such systems with “autopilot” systems.  However, mechanical input devices, which require sufficient space to accommodate their range of motion, and access by the human operator, continue to be required. 
In addition to packaging limitations, traditional control inputs have been difficult or impossible for individuals with physical limitations to use.  For example, quadriplegics and paraplegics are unable to control conventional vehicles using standard control inputs.  Although modifications to vehicle control systems can be made, for example, “hand controls” can be used in place of foot operated pedals in a motor vehicle to enable paraplegics to drive, such systems are typically cumbersome, and require good motor control on the part of the operator.  For quadriplegics, joysticks, “sip and puff”, and tongue controlled input devices are available.  Although such devices are promising, additional options would be desirable.  In addition, for critical activities, such as driving an automobile or flying an airplane, accurate interpretation of control inputs, and distinctions between different inputs, are critical.