Papers by Author: Koichi Maru

Abstract: A method of inexpensive material tester is proposed for realizing an instrument based on the levitation mass method without the use of pneumatic linear bearings and a Zeeman type two frequency He-Ne laser. As an example a material tester using the pendulum, which evaluates the mechanical response of general objects against impact forces, is developed. The characteristics of the restoring force are determined using the same instrument under the free-swing condition without the object under test. To demonstrate the performance of the developed instrument, the impact response of a gel block is determined.

Abstract: A simple single-axis tilt mechanism for precision control of the down-slope component of gravitational force is proposed. Precise tilt motion is realized by using a wedge shaped block and a linear actuator driven by a stepping motor. The proposed mechanism can be easily constructed by standardized aluminum frames for the skeletal structure. The measurement result indicates that the tilt angle can be controlled by adjusting the position of the linear actuator and good reproducibility of the tilt angle is achieved by using the proposed tilt mechanism.

Abstract: This paper introduced how to estimate motion pose using binocular stereo camera. The Euler angle of the moving object was computed by a rotation matrix. The result of the experiment shows astronaut was rotated during the parabola experiment. This work was useful for space research and space scale.

Abstract: A method for reducing the size and cost of optical system for precision measurement based on the Levitation Mass Method (LMM) is proposed. In the LMM, a mass levitated using a pneumatic linear bearing with sufficiently small friction is made to collide with the object being tested. The velocity and acceleration of the mass are measured using a compact optical interferometer. The size of the optical system can be drastically reduced by using a planar lightwave circuit (PLC), in which several optical elements are arranged on a planar surface of a silica or semiconductor substrate. Several applications of the PLC to precision measurement will be discussed.

Abstract: Integrated laser Doppler velocimeters (LDVs) using integrated waveguide technology are reviewed. LDVs have been widely used to measure the velocity of a fluid flow or rigid object in various research and industries. However, bulk optical systems used in conventional measurement need special care from temperature change and vibration, which become the expected sources of uncertainty in measurement, due to large optical path length. Therefore, the optical system should be more compact. The LDV can be drastically reduced by using a planar lightwave circuit (PLC). The possibility for realizing several types of novel integrated LDVs, including a wavelength-insensitive LDV, a scanning LDV and a multi-point LDV, is discussed.

Abstract: A testing method for precision force measurement using a small pendulum based on the levitation mass method (LMM) has been developed. In this method, the force acting on the material to be tested is measured using an optical interferometer. In this paper, a collision test of the spring and the pendulum is performed. As the result of the test, the maximum force on the spring was evaluated as approximately 0.533 N. To demonstrate the performance of the developed instrument, the impact responses of the pendulum are accurately evaluated. The possible applications of the developed method are also discussed.

Abstract: This paper reviewed the present status and the future prospects of a method for precision mass and force measurement based on levitation mass method (LMM). The LMM has been proposed and improved by the author The mass which levitated using a pneumatic linear bearing in LMM is used to producte a inertial force which used as the reference force applied to the objects under test, such as to force sensor calibration, material and structure test. The inertial force is calibrated only from Doppler shift frequency. The stability of laser’s wavelength has improved in the LMM. The futhure work and the method to improve the precision have described.

Abstract: In this paper, mass measurement devices (MMDs) developing by the authors for use in the International Space Station (ISS) are reviewed. First, Space Balance, which is a small mass measurement device (SMMD), is reviewed. In Space Balance, the momentum conservation between two objects, the subject mass and the reference mass, are compared. Then Space Scale, which is a body mass measurement device (BMMD), is reviewed. In Space Scale, a human subject is pulled using rubber string. Force is measured using a force transducer and acceleration is measured using optical interferometer. Both Space Balance and Space Scale have shown high accuracies in the ground experiments.