Integrated Actuators

Besides microfluidics the human-machine interaction, especially the imaging systems, could enormously benefit from the availability of large-scale integrated actuator systems. Such systems could provide an additional mechanical data channel intended for the sense of touch of the human, which is a very sensitive aesthesia. A first impression about the performance of a high-resolution tactile display gives the artificial skin (Fig. 15a). 

Main drives High demands on the static, dynamic and thermal stiffness, and on the life of bearings and spindles Autonomous adjustment of pre-loading by integrated actuators... 

Park et al. fabricated a microfluidic biochip with integrated actuation electrodes to isolate an MCF7 cell and actively manipulated the cell by the DEP force into desired locations [11]. 

Shape control and active flow, the mainly static deformation of space and aerodynamic structures to either improve communication performance of antennas or adapt structures to optimum aerodynamic fluid flow, both achieved by integrated actuation mechanisms. 

One adaptronic approach to reduce torsional vibrations was to integrate actuators within the diagonal stiffening struts of the car underbody (Fig. 8.24) [150,151]. Different actuators have been investigated, piezoceramic stacks, hydraulic cylinders and hydraulic muscles. Control approaches like adaptive feed-forward and feedback were implemented and significant vibration reductions were achieved (Fig. 8.24). To commercialize this affirmative active concept system cost, size, complexity and power consumption must be further reduced. 

Finally, it is worth noting that the development of adaptronic components to be used for the most diverse machine tools and manufacturing plants is a multidisciplinary task requiring the collaboration of production, civil, machine and control engineers. A multidisciplinary approach of this task is crucial for the successful implementation of optimised systems with structurally integrated actuators and sensors and adaptive control algorithms in machine tool applications. 

In this article we refer to an actuator as closed when the associated chamber or channel volume is minimized, and as open when that volume is maximized. The volume in the closed position is called the dead volume, and the difference between the volume in the open position and the dead volume is the stroke volume. The stroke volume divided hy the dead volume is the compression ratio. Compression ratio is particularly important when purrping gases, since the amount of gas ejected from the actuator is reduced hy the compressihility of the fluid. In pure liquids this effect is much less, hut compression ratio plays an important role in determining how severely bubbles impact a particular purrp. In classifying micro-pumps, a distinction is sometimes made between integrated actuators - fabricated along with the other components of the microfluidic system - and external actuators - fabricated separately and attached later. It is common to see peristaltic micropumps of either kind. 

The sequence of theories developed throughout the foregoing chapters, leading the way from piezoelectric composites via adaptive laminated composite shells to adaptive thin-walled beams, allows for examinations of almost arbitrary complexity. The attempt to provide examples for the full spectrum of capabilities will be dropped in favor of an application-oriented approach. Hence, the subsequent investigations will be carried out in view of the integral actuation of structures with certain similarity to helicopter rotor blades. 

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