荒木 望

The coefficient of static friction is one of the basic factors of actuator performance; it influences the operational characteristics of actuators. In this present study we focus on the dependence of the coefficient of static friction on the time of stationary contact through experiments .We start with the development of a static friction measurement device that can control extremely short contact time durations (approximately 5 ms), using an inertia drive system.

This paper describes novel biaxial tensile test technique for a film specimen to investigate material responses to uniaxial and biaxial tensile forces. We have developed biaxial tensile tester that consists of four sets of actuator, loadcell, and displacement meter in order to apply an arbitrary amount of tensile force to a film specimen in each axis. With the uniaxial test specimen of sputtered Al-Si-Cu film at room temperature (RT), average Young's modulus of 66.4 GPa and yield stress of 139.1 MPa have been obtained. With the biaxial test specimen, the yield locus has been evaluated by applying biaxial stresses with various strain rate ratios. The obtained yield stresses could be fitted by the yield criterion based on Hill equation, indicating that the flow stress under biaxial stress condition differ from that under uniaxial condition. Information about the yield locus would be useful for the structural design of MEMS including Al-Si-Cu film structures subjected to biaxial stresses.

This paper considers camera calibration method for stereo camera systems. Recently, the technique using planar patterns has been proposed in this subject. In this technique, multi-camera systems calibration is realized only by capturing a planar calibration pattern with known reference points that placed at three or more locations. Although this planar-based method is easy to apply to real stereo-camera system, it has the problem that camera parameters are not obtained with enough accuracy when observation noise of reference point on a camera image plane is large. To solve this problem, we proposed a new approach that applies the Unscented Kalman filter (UKF) to planar-based method. UKF is the state estimation method for nonlinear systems developed in recent years. The proposed method's effectiveness has been clarified through computer simulation and experiment.

Surface roughness and specular glossiness are generally used as evaluation indexes of processing surfaces. In evaluating a metal surface, it is important to know how external fineness of the processing surface and an ideal specular surface are different. Here, this difference is called a "specular rate". It is impossible to evaluate specular rate using surface roughness or specular glossiness. Consequently, this paper considers new evaluation indexes for quantitatively evaluating specular rate of a metal surface. First, the method for estimating the impulse response between a certain pattern image and it's reflected image on an evaluated surface is proposed. This impulse response indicates the optical sharpness of a reflected image. Then, the surface's specular rate and directionality indexes are defined by estimated impulse response. The validity of these indexes has been verified by surface evaluation experiments on processed SUS304 stainless steel samples.

This paper considers parameter identification of a 2 link underactuated Acrobat robot called Acrobot. According to parameter identification studies, the method using Extended Kalman Filter (EKF) has been proposed. The Acrobot considers here is assumed to be influenced kinematic and viscouse friction, and it's equation of motion includes discontinuous terms. Unfortunately, EKF can't be executed such an indifferentiable nonlinear systems. Then we proposed a new method using the Unscented Kalman Filter (UKF) for parameter identification of the Acrobot. UKF is the state estimation method for nonlinear systems developed in recent years, and this method is applicable even when there is a discontinuity in nonlinear systems. The proposed method's effectiveness has been clarified through computer simulation and experiment.