Linear actuated device

Linear actuated devices Pressure driven laminar flow WIicrofluidic large scale integration Segmented flow microflu id tcs... 

Linear actuated devices control liquid movement by mechanical displacement (e.g. a plunger). Liquid control is mostly limited to a one-dimensional liquid flow (no branches or alternative paths) with the corresponding possibilities and limitations to assay implementation. The degree of integration is very high, with liquid calibrants and reaction buffers pre-stored in pouches. 

One of the first examples of a linear actuated device was the i-STAT for quantitative bedside testing, introduced in the early 1990s by Abbott Point of Care Inc., NJ, USA. It relied on active liquid actuation by displacement... 

Mechanical force can be more easily controlled using fluid power. The simple use of valves and rotary or linear actuators control speed, direction and force. The simplicity of hydraulic and pneumatic components greatly increases their reliability. In addition, components and overall system size are typically much smaller than comparable electrical transmission devices. 

The energy within a hydraulic system is of no value until it is converted into work. Typically, this is accomplished by using an actuating device of some type. This actuating device may be a cylinder, which converts the hydraulic energy into linear mechanical force a hydraulic motor, that converts energy into rotational force or a variety of other actuators designed to provide specific work functions. 

One of the outstanding features of fluid power systems is that force, generated by the power supply, controlled and directed by suitable valving, and transported by lines, can be converted with ease to almost any kind of mechanical motion. Either linear or rotary motion can be obtained by using a suitable actuating device. 

In a sKght modification to this solid-state actuator configuration, Lu et al. [108] reported the fabrication and performance of sohd-state electrochemical linear actuators with a unique polyanOine soKd-in-hoOow fiber configuration. The basic device structure consists of a polyanOine solid fiber... 

It is interesting to analyse the behavior of linear actuators because most applications are based on such actuators. To simplify the presentation, we can consider an actuator with one end working either free (no load) or against a purely resistive load i ioad (in kg/s) the other end of the actuator is clamped. The vibration against this load produces an output power (either mechanical or acoustic), and its behavior is representative of any magnetostrictive device. Most of them can be analysed as whole systems, including a compliance (at constant field), an effective mass M and a mechanical... 

State-of-the-art CP devices need very low driving voltages (order of 1 V), producing strains of the order of 1... 10% for linear actuators and rotations up to 90° for benders, with large active stresses (up to tens of MPa). Nevertheless, such interesting performances correspond to several drawbacks, such as high response times and short lifetimes, whose relevance has to be evaluated in relation to the specific application of interest. 

Carpi, F. and De Rossi D. Contractile monoUthic linear actuators, in Dielectric elastomers as electromechanical transducers. Fundamentals, materials, devices, models applications of an emerging electroactive polymer technology, (Carpieds, F., De Rossi, D., Kombluh, R. et al.), Elsevier Press, Amsterdam, The Netherlands, 2008. 

In the near future, further development in new soft microelectrochemical devices based on conjugated polymer actuators will require their complete conception, operation, and interfacing systems all integrated on a single substrate to allow easy and independent operation. This still poses a real challenge that remains to be overcome. Also, it would be of great interest to develop microactuators with linear actuation to further extend the tool box of CP microactuator devices. 

Along the same lines, MEMS devices with on-chip force sensors and actuators have been developed to measure the load-displacement relationship of single nanofibres (Fig. 4.21a) [231]. A MEMS system which is composed of two movable components, namely pulling and bending cantilevers was used by Jaeger et al. (Fig. 4.21b) [232]. Fee et al. [230] utilised a precise screw-type linear actuator and a 1.1 N load cell that were both controlled by a customised LabView program. 

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