K. Ikuta

Real three dimensional micro fabrication using stereo lithography and metal molding

A technique for three-dimensional micro fabrication using stereo lithography is proposed. It is called the IH process (integrated hardened polymer stereo lithography) and is suitable for microstructures made of both polymer and metals. The experimental apparatus developed and the fabrication of various 3-D microstructures, such as bending pipe, connected pipe, microcoil spring, and one-way valve, are described.<<ETX>>

Mathematical model and experimental verification of shape memory alloy for designing micro actuator

An advanced mathematical model of a shape memory alloy (SMA) useful for designing SMA micro-devices is proposed and applied to coil spring theory to analyze the appropriate mechanical and electrical characteristics. This model can handle three phases of the SMA: the parent phase, the martensitic phase, and the R-phase. of three steps. First, the mechanical properties of the three phases are modeled at the solid mechanics level. Second, a model of thermoelectric transformation is obtained at the thermodynamic level. Finally, the first and second steps are combined. The model was applied to coil spring theory and was verified successfully by experiments under general conditions.<<ETX>>

Non-contact magnetic gear for micro transmission mechanism

A unique transmission mechanism using a non-contact magnetic gear (NCMG) is proposed for micro and miniature electromechanical systems. A miniature NCMG has been produced and the basic characteristics were evaluated experimentally. The theoretical approach for analyzing the transmittable torque of the NCMG was developed and verified experimentally. It is concluded that the NCMG system has great potential for use in safe miniature transmission mechanisms for medical applications and in micro transmission systems for microelectromechanical systems.<<ETX>>

Tiny silent linear cybernetic actuator driven by piezoelectric device with electromagnetic clamp

A type of miniature linear actuators called a cybernetic actuator for biomedical applications is described. This actuator has four driving states: free, increasing, decreasing, and lock. The free and lock states can release excessive applied load from outside to provide safety characteristics for both human and micromechanisms. Miniaturized linear cybernetic actuators combining a piezoelectric impact drive with electromagnetic clamping were designed and developed. Feasibility and basic performance of the actuators were confirmed by theory and experiments. Improved performance in terms of maximum speed, energy efficiency, and silent drive as a miniature linear actuator were verified successfully by using a controlled friction impact drive.<<ETX>>

Miniature cybernetic actuators using piezoelectric device

A new type of miniature actuator, the so-called cybernetic actuator, for medical application has been proposed and developed. The cybernetic actuator has four driving states: free, increasing, decreasing and locked. A rotary-type cybernetic actuator and a linear-type cybernetic actuator driven by piezoelectric devices have been constructed. The feasibility of both actuators was verified by driving experiments.<<ETX>>

Two dimensional mathematical model of shape memory alloy and intelligent SMA-CAD

A generalized mathematical model for a shape memory alloy in a two-dimensional field is formulated, and the alloys characteristics are calculated numerically. Solid mechanics and thermodynamics of phase transformations are used in the model, which can be used to estimate not only the two-dimensional distribution of the stress but also the transformation ratio of any SMA device. This model is used in an intelligent CAD system for designing and simulating micro/macro SMA devices.<<ETX>>

Development of miniature cybernetic actuator driven by piezoelectric device

New types of miniature actuators so called cybernetic actuator for biomedical robotics are developed. The cybernetic actuator has four driving states: free, increasing, decreasing and lock. The state of free and lock provides safety characteristics for both human and mechanism by avoiding damage from overload. The rotary type and linear type of cybernetic actuators are designed and developed. Feasibility of both actuators is verified by experiments. Four driving states are confirmed and unique driving principle is verified successfully.<<ETX>>

Development of micro actuator using shape memory alloy thin film

Basic research for the micro actuator using TiNi shape memory alloy (SMA) is conducted from the crystallographic point of view. SMA (TiNi) thin film is fabricated by sputter deposition. First, the influence of substrate temperature on crystal structure is verified by measuring resistivity-temperature curve and X-ray diffraction. Though high temperature substrate conditions make TiNi film in regular crystal, an amorphous structure appears at low substrate temperature. Next optimal composition of sputtered SMA thin film is found by SSQ. The negative slope of the resistivity curve due to phase transformation between R-phase and parent phase is observed. Finally, annealing methods are examined to crystallize amorphous TiNi.<<ETX>>