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Posted: December 15, 2009
Help Noliac Pick the Best Amplified Actuators
(Nanowerk News) Noliac has developed a new amplified diamond actuator which allows large controllable displacements, stability with varying temperatures together with high forces for a minimal weight. The scope of combinations between free stroke and blocking force is extensive – will you help us evaluate which combinations could become interesting standard products?
The combinations of the amplified actuators are based upon CMAPs of different sizes, e.g. 3x3 mm, 5x5 mm, 7x7 mm, 10x10 mm and 15x15 mm.
High stroke, high forces and low weight
This new amplified actuator will find applications in systems requiring large controllable displacements together with high forces for a minimal weight.
The diamond frame is also more compact than many commercially available amplification systems. In addition, the lower mass and optimised stiffness imply higher mechanical resonance compared to other solutions, allowing operation at higher frequency.
This could be in other fields such as aeronautics, space, optics, military applications and others where you wish for high stroke, high force and low weight.
The diamond principle
The new design was developed to address the limitations in terms of energy density and temperature stability. It is based on four piezoelectric stacks, connected in pairs. Each stack is hinged at its ends and maintained in place with a small angle.
The whole assembly is preloaded through the use of a tension member maintaining the fixed members in place. This ensures that the piezoelectric stacks operate in optimal conditions.
The actuator is operated as follows. When the applied voltage is increased on one pair of stacks, it is decreased on the other pair. This contributes to a movement of the output member in one direction. It should be noted that in the case of a free displacement, the tension in the piezoelectric stacks as well as in the tension members (therefore the preload) remains almost constant.
Upon temperature change, differential thermal expansion between the ceramic and the other materials in the assembly will lead to a change in force repartition. This will result in a change in the internal preload. However unlike most of the existing schemes presented in the literature, this will not result in a movement of the output member.
Thanks to the compact design and the large proportion of active material, this design was expected to provide high performance levels as well as high energy density.