Monoform Structures for Amplifying Motion or Force
Compliant monoform mechanisms can produce significant amplification (65X) of small deflections in a compact, high frequency system without the links and joints of a conventional mechanism. These large movements can be achieved with zero backlash and without bearings or lubrication at high speed with exceptional reliability due to the distribution of mechanical stresses throughout the whole mechanism. It also means that at any scale, a compliant mechanism can also be designed to amplify force (with small displacements) or displacement (with little force) to suit a desired outcome.
In high frequency systems, at micro-scale, it’s possible to design a mechanism that does not rely on resonance to achieve a desired displacement. This greatly extends the applicability of smart materials actuators, which by themselves are typically limited to small strains and correspondingly small deflections (10 µm - 1000 µm). By integrating a joint-less, backlash-free compliant mechanism with a smart materials actuator, the force and stroke can be tailored to suit a wide range of specific needs.
Illustrated above shows how a compliant mechanism alters the force-displacement characteristic of a smart materials or conventional actuator or actuators. The compliant mechanism can increase the displacement (displacement multiplication), or increase the force (force multiplication). Using newly developed optimization techniques, it is possible to design compliant mechanisms that can achieve multiplication factors of 65X or more.
A voice coil actuator is the simplest type of electric motor and generates linear motion in one direction, and oscillating motion by reversing polarity. Adding a compliant displacement amplifier can simultaneously provide rectilinear motion guidance to the voice-coil as well as amplifying the force or displacement output capability of the actuator. By exploiting low impedance motion amplification, it is possible to obtain large amplitude output motion at frequencies where the voice coil motor cannot directly produce the required motion alone.
Applying a compliant monoform mechanism to a piezoelectric actuator greatly increases the working envelope of this sort of smart material actuator. Piezoelectric translators (transducers) are high precision ceramic actuators that convert electrical energy directly into linear motion. They are ideal for high speed, or force, with virtually unlimited resolution applications such as semiconductor testing and inspection, super-resolution microscopy, bio-nanotechnology, astronomy and aerospace technology. Because of the compliant mechanism The performance capabilities of this actuator far exceed that of currently competing piezo-amplifier systems and bender-type configurations in terms of block force, stroke, and frequency capability - opening the door to new, compact, high-power actuation systems.