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Designing Experiments with Control Theory in Mind
Published in Richard J. Jagacinski, John M. Flach, Control Theory for Humans, 2018
Richard J. Jagacinski, John M. Flach
A second example of opening the loop comes from the neural innervation of muscles. Alpha motor neurons have their cell bodies in the spinal chord, and the neurons extend out to individual muscles. The neural signals activate muscle fibers and cause them to contract. This contraction is a basic physiological mechanism for generating movement. The alpha motor neurons have short branches close to the spinal cord that excite other neurons called Renshaw cells. The Renshaw cells in turn inhibit the activity of the alpha motor neurons (Fig. 26.2, Roberts, 1967; see McMahon, 1984, for a review). Thus, there is a negative feedback loop that modulates the activity of the alpha motor neurons. The inhibitory connections of the Renshaw cells to the alpha motor neurons can be blocked by either strychnine or tetanus toxin. The result of this chemical blocking is that the muscles go into convulsion (e.g., see Thompson, 1967, pp. 202–207). An interpretation of this effect is that the chemical blocking agents have effectively opened the feedback loop that normally modulates the response of the alpha motor neuron. If the gain of the feedback loop is normally G/(1 + GH) (see chap. 2), then by blocking the feedback loop H is essentially set to zero, and the effective gain of the alpha motor neurons then becomes G. If G is considerably greater than G/(1 + GH), then the muscles will be overstimulated, and convulsions will result (Roberts, 1967).
IoT-based patient stretcher movement simulation in smart hospital using type-2 fuzzy sets systems
Published in Production Planning & Control, 2023
C. B. Sivaparthipan, M. Anand, Nidhi Agarwal, Mallika Dhingra, Laxmi Raja, Akila Victor, S. A. Amala Nirmal Doss
The bariatric algorithm is used when the above conditions are met. The first one is that the patient’s functional activity is dependent, and they can partially bear their weight. Then, they may not be cooperative but must understand the instruction. The guider must avoid the shearing force, and for all patients, the move should be ½ lower than the destination surface. The patient’s position is the right width, and make sure for it because the excess need from the caregiver is not required. The speciality beds are not used if transferring the patient from one place to another. In this case, the bariatric sling is used. We can’t move stretchers with the heavy weight of the patients for transferring. Alias with using a traditional stretcher, we can use a bariatric stretcher to transfer patients from one place to another, even if the patient is overweight (Tezel, Bilge, and Özkan 2021). The stretch reflex, also known as the myotatic reflex, is the increase in contractility of a muscle in response to passive stretching as long as the strain is within physiological limitations. When a stretch reflex is activated, it generates not only the contraction of the synergistic muscles but also relaxation, i.e. an inhibitory impact on the antagonist’s muscles. The impulse is delivered from the stretched muscle spindle to the alpha motor neuron when a stretch reflex occurs.