The other responses observed in the fingers after immersion in cold water are a continuous state of vasoconstriction, slow steady and continuous rewarming and a proportional control form in which the blood vessel diameter remains constant after an initial phase of vasoconstriction.
22.
The proportional control system is more complex than an on-off control system like a bi-metallic domestic thermostat, but simpler than a proportional-integral-derivative ( PID ) control system used in something like an automobile cruise control.
23.
In the late 1950s, RC hobbyists had mastered tricks to manage proportional control of the flight control surfaces, for example by rapidly switching on and off reed systems, a technique called " skillful blipping " or more humorously " nervous proportional ".
24.
Direct proportional control works well when each joint of the exoskeleton is actuated in one direction ( uni-directional actuation ), such as a pneumatic piston only bending the knee, but is less effective when two joint actuators work in opposition ( bi-directional actuation ).
25.
The radio gear used to control the rudder function on the American-developed Azon guided ordnance, however, was a fully proportional control, with the " ailerons ", solely under the control of an on-board gyroscope, serving merely to keep the ordnance from rolling.
26.
Experiments have shown that three other vascular responses to immersion of the finger in cold water are possible : a continuous state of vasoconstriction; slow, steady, and continuous rewarming; and a proportional control form in which the blood vessel diameter remains constant after an initial phase of vasoconstriction.
27.
These methods include the use of modulated infrared light in the optical system inside the sensor, the lightweight, easy-to-wrap finger cuff with velcro fixation, a new pneumatic proportional control valve principle, and a set point strategy for the determining and tracking the correct volume at which to clamp the finger arteries the Physiocal system.
