Actuator dynamic

This analysis is based on an idealized model of the level of a tank and does not consider sensor or actuator dynamics and does not consider that horizontal tanks do not have a constant cross section. For these reasons, it is recommended that Equations (15.14) and (15.15) be used as initial estimates of the tuning parameters and that an on-line tuning factor, F be used to tune for the desired level control performance ... 

Modeling the actuation response of IPMC for robust control of IPMC actuators is described in references 12 and 13. [12—13] Step response of actuators can be used for identification of actuator dynamics to derive a second order transfer... 

Leaks, back pressure, and actuator dynamics all influence the performance of peristaltic pumps. Leaks and back pressure effects will alter the distribution of fluid as actuators open and close. The dynamics of the actuators determines the maximum actuatitm rate, which in turn limits the maximum flow rate. These effects can be incorporated into lumped-parameter models for analysis and simulation. We do not pursue this further in this entry, but refer the reader to the literamre. One general approach is presented in Ref. [7]. Also relevant for further smdy are Refs. [6, 8], and [13], which present dynamic models for pneumatic and electrostatic pumps, respectively. All of these works are applied to liquid pumps. For gas pumps, or robustness to bubbles, compressibility becomes a factor. Some considerations of micropumps for compressible fluids may be found in Ref. [1]. Finite-element analysis of individual chambers can also be used to obtain detailed predictions of pump dynamic performance. 

Despite its simple looking, (5.12) captures the dominant structure of the actuator dynamics and, as shown in experimental results, is instrumental in effective control design. 

As an example of modeling IPMC-based robotic systems, in this section we present a model for robotic fish propelled by an IPMC caudal fin. The model captures the intrinsic actuation dynamics of IPMCs, as presented in Section 4.2, and the complex hydrodynamic interactions between the IPMC, fluid, and a passive attachment for enhancing propulsion. Given... 

Lee, W. Polymer Gel Based Actuator Dynamic model of gel for real-time control. Ph.D. Thesis, MIT (1996)... 

This chapter describes an actuated dynamic hand splint with variable compliance regulated by new DE contractile actuators. The concept is described below, with reference to Figure 24.4. 

Other practical effects include control-structure interaction, actuator dynamics, and digital control implementation. The reliability of applied semi-active structural control systems and practical apphcations and verification for active and semi-active vibration control of buildings in Japan have been studied by Ikeda (2009). 

The stiffness characteristic of the positioner/actuator varies with frequency. Figure 8-75Z indicates the stiffness of the positioner/actu-ator is high at low frequencies and is directly related to the locked-stem pressure gain provided by the positioner. As frequency increases, a dip in the stiffness curve results Trom dynamic gain attenuation in the pneumatic amplifiers in the positioner. The value at the bottom of the dip is the sum of the mechanical stiffness of the spring in the actu-... 

FIG. 8-75 Frequency response curves for a pneumatic positioner/actuator (a) input signal to stem travel for a 69-inch spring and diaphragm actuator with a 1.5-inch total travel and. 3-15 psig input pressure (h ) dynamic stiffness for the same positioner/actuator. 

An alternative form of split injection is the timed split technique, Figure 6.11 [130,131,133]. In this case the column is connected directly to the valve and the valve actuator is controlled electronically to turn the valve to the inject position and back very rapidly with only a portion of the sample in the loop displaced to the column. Timed split allows variable volumes to be injected by changing the valve actuator tine and provides more reproducible splitting than the dynamic split technique. However, it suffers from many of the same problems as dynamic split, namely, poor accuracy, split ratios that depend on pressure, and high detection limits. 

To make use of empirical tuning relations, one approach is to obtain the so-called process reaction curve. We disable the controller and introduce a step change to the actuator. We then measure the open-loop step response. This practice can simply be called an open-loop step test. Although we disconnect the controller in the schematic diagram (Fig. 6.1), we usually only need to turn the controller to the manual mode in reality. As shown in the block diagram, what we measure is a lumped response, representing the dynamics of the blocks Ga,... 

S. Martin, J. Ha, J. Kim, T. Strong, G. Cha, and R. Brown, ISE arrays with improved dynamic response and lifetime, in Tech. Digest of the Solid-State Sensor, Actuator, and Microsystems Workshop, pp. 396-399. Hilton Head, SC (2004). 

A. Steinschaden, D. Adamovic, G. Jobst, R. Glatz, and G. Urban, Miniaturised thin film conductometric biosensors with high dynamic range and high sensitivity. Sens. Actuators B. B44, 365-369 (1997). 

In a comprehensive test program the characteristic functions of the ionization current and the primary air ratio as well as of the primary air ratio and the fan supply voltage have been gathered. A closed loop control has been designed on this basis, which also includes appliance start-up and calibration as well as a suitable, dynamic set point and actuator controls. 

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