We develop several types of actuator, driven under cryogenic and high magnetic fields. We develop thin electromagnetic motors driven without reduction mechanism, and mobile power source for pneumatic actuators. We use ultrasonic, electromagnetic or fluid phenomenon for these requests.
Ultralow temperature environment provide important measuring condition in advanced scientific research area. The ultralow temperature is near the liquid helium temperature, 4.2 K. In the condition, there are demands for actuators that can drive in ultralow temperature conditions. Although an actuator which has high rotation speed in ultralow temperature condition have not existed.
We have fabricated and evaluated a small ultrasonic motor that was driven under cryogenic temperature conditions. Our motor is simulated and designed for ultralow temperature using FEM thermal-structural analysis. In this simulation, we used material properties as non-linear with temperature.
We have succeeded in driving the motor at ultralow temperature. The rotation speed and initial torque was 422 rpm and 1.3 Nm when the temperature was 4.5 K. The rotation speed is 400 times that of the existing actuators.
Nuclear Magnetic Resonance (NMR) has been developed to the means indispensable to various fields. For example, acquisition of information of the molecular structure, observation inside the human body and so on. Solid state NMR is possible to study in detail the microscopic structure of amorphous samples and molecular motion. Pneumatic turbine capable of high-speed and high-precision rotation is generally used as a method of rotate the sample.
On the other hand, in cryogenic environment, NMR is possible to reduce the noise and examine the change of physical properties. But when using pneumatic turbine in extreme environments, the system becomes large and complex. It is very difficult to adapt Pneumatic system to vacuum, high pressure environment in terms of drive principle. Therefore, the actuator that can be used without using a complex system is needed.
Ultrasonic motors are suitable for miniaturization. In addition, ultrasonic motors have a feature that hardly affected by the magnetic field for friction drive. Ultrasonic motors are expected to application to a vacuum environment and a cryogenic environment. In this study, our aim is to apply an ultrasonic motor to rotating mechanism of a NMR method in a high magnetic field of 7 T.
Recently, several types of rotary switches are used for operational devices of the portable electric equipments. However, these switches can just present the designed force sensations only passively. This research aims at development of the thin electromagnetic motor which includes reduction mechanism and can be applied to portable electric equipment.
Stable rotational work of the thin electromagnetic nutation motor was realized by rubber skin courting. In addition, for the purpose of high-speed rotation and higher torque, we developed electromagnetic wabble motor. The wabble motor has a speed reducer built-in stepping motor (30 mm in diameter and 5 mm in thickness). Maximum rotational speed and torque of the wabble motor are 8.6rps and 0.37mNm. Moreover, the smooth rotation by drive frequency 280Hz could be checked, and improvement in performance. A system which can presents force sensation actively by using developed motors for rotary switch was fabricated.
While various types of pneumatic actuator have been developed, they need big and heavy pneumatic power source. This makes pneumatic actuators work with wired actuators. We focus on reversible chemical reaction, because it resolves energy efficiency and suitable mobility.
This new pressure source is controlled by a proton exchange membrane fuel cell (PEMFC). PEMFC consists of two platinum electrodes and a proton exchange membrane. Electrolysis/synthesis of water is reversible chemical reaction, and also it is controlled by electric current. So, that is easy to adjust and control the gas pressure.
It works as a fuel cell, when synthesis of water realizes energy recovering. This new pressure control device is compact, light-weight, silent and high energy efficient.
Pressure increase/decrease is controlled in a few seconds. Energy recovery ratio improves 14%.