scholarly journals Oscillation Amplitude-controlled Resonant Accelerometer Design using Aautomatic Gain Control Loop

1997 ◽  
Vol 200 (9) ◽  
pp. 1383-1402 ◽  
Author(s):  
R Kittmann

An adaptive gain control system of a proprioceptive feedback system, the femur­tibia control loop, is investigated. It enables the joint control loop to work with a high gain but it prevents instability oscillations. In the inactive stick insect, the realisation of specific changes in gain is described for tibial torque, for extensor tibiae muscle force and for motoneuronal activity. In open-loop experiments, sinusoidal stimuli are applied to the femoral chordotonal organ (fCO). Changes in gain that depend on fCO stimulus parameters (such as amplitude, frequency and repetition rate), are investigated. Furthermore, spontaneous and touch-induced changes in gain that resemble the behavioural state of the animal are described. Changes in gain in motoneurones are always realised as changes in the amplitude of modulation of their discharge frequency. Nevertheless, depending on the stimulus situation, two different mechanisms underlie gain changes in motoneurones. (i) Changes in gain can be based on changes in the strength of the sensorimotor pathways that transmit stimulus-modulated information from the fCO to the motoneurones. (ii) Changes in gain can be based on changes in the mean activity of a motoneurone by means of its spike threshold: when, during the modulation, the discharge of a motoneurone is inhibited for part of the stimulus cycle, then a change in mean activity subsequently causes a change in modulation amplitude and gain. A new neuronal mechanism is described that helps to compensate the low-pass filter characteristics of the muscles by an increased activation, especially by a sharper distribution of spikes in the stimulus cycle at high fCO stimulus frequencies.


Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1335
Author(s):  
Daishin Isobe ◽  
Noriyuki Hori ◽  
Shin Kawai ◽  
Keisuke Yagi ◽  
Triet Nguyen-Van

Nowadays, stepping motors are usually used as precise actuators in various new scientific fields, such as syringe pumps, blood analyzers, and bio-3D printers. Controlling rotation of the stepping motor without speed fluctuation under no-load conditions plays an important role in improving the accuracy of the machine’s drive. This paper proposes a digital control method for a five-phase hybrid stepping motor. The proposed controller includes an original control loop and a PI adaptive integration gain control loop. The original digital control loop is redesigned from the analog controller by using the direct PIM method. The PI adaptive control loop is added to the original control loop in a parallel way to remove a steady deviation of the motor and suppress a physical saturation factor inside the plant. Lyapunov stability theory is used to prove a stability condition of the PI regulator gains. Experimental results show that the proposed controller can suppress the chattering caused by the switching structure and gives performances as good as that of the commercial analog controller in a high rotation speed range without fluctuation.


1985 ◽  
Vol 2 (2) ◽  
pp. 132-140
Author(s):  
Yang Yipei ◽  
Zheng Yijia
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document