Browsing by Subject "microprocessors"

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Open Access
COMPARATIVE ANALYSIS OF MICROPROCESSORS IN UPPER LIMB PROSTHETICS
(2002) Lake, Christopher; Miguelez, John M.
The recent emergence of microprocessor based prosthetic control for the individual with upper limb deficiency has significantly expanded the spectrum of treatment options and inclusion criteria for this patient population. Microprocessors can accept a wide variety of input devices and ranges enhancing an individual’s prosthetic function allowing control options for individuals who were at one time not candidates for such prosthetic management. Additionally, myoelectric control parameters can be adjusted to optimize function while retaining the flexibility to individualize each prosthesis.
Open Access
MICROPROCESSOR CONTROL FEATURES
(2002) Sjonnesen, Gary; Prigge, Pat
The very Underlying Principle of Control for the Otto Bock Myoelectric System is “Muscle contraction should lead to function.” If you think about picking up an object with your sound hand, you simply pick up the object. An amputee must concentrate on more activities than that of an individual with a sound hand. If an amputee wears a prosthesis they must first open their hand, then position their hand over the object, then close their hand around the object and finally determine how much grip force should be applied to the object. With all of those things to consider, the relationship between their input signal (EMG) and the output of the hand (motor speed or grip force) must remain constant to minimize the learning curve. If the relationship is variable, the patient must relearn how to control the hand depending on the variables and thus control can be very unpredictable. The analogy is getting into someone’s car that just had a brake job done. You are used to putting high pressure on the pedal in your car in order to slow the car down so when you touch the pedal in the other car, it brakes very abruptly. You need to relearn the relationship between pedal pressure and braking speed. This is something we need to avoid in myoelectric fittings. Therefore, the microprocessor control in the Otto Bock system contains features to minimize the effects of outside influences.
Open Access
UNIQUE DEVICE-SELECTION STRATEGIES FOR POWERED ELBOWS
(2002) Wallace, Craig
In an upper limb prosthetic system Mode Selection gives the user the ability to utilize one or two input signals to control more than one prosthetic device. Mode Selection is defined here as the means by which a user shifts control to the different electric devices in their prosthetic system. Mode selection has been done for many years in several forms, each of which has a benefit to the user. The simplest mode selection scheme uses a simple switch. Other types involve the use of myoelectric signals that cross a specific threshold, or a rapid co-activation of two myoelectric signals to perform the mode selection. This latter method of mode selection has become a basic cornerstone for mode selection. However, the performance of the prosthesis must match the desired goals of the user. If such a technique cannot be mastered then other approaches must be made available.