In the last few years, lasers have found new applications as tools for ceramic machining which is laser-assisted machining(LAM). LAM process for the machining of difficult-to-machine materials such as structural ceramics, has recently been studied on silicon nitride workpiece for a wide range of operating condition. However, there have been few studies on rake angle in LAM process. In this paper we analyzed difference of machinability between positive and negative rake angle in tools. We have obtained interesting results that we could eliminate chattering, lower specific cutting and cutting ratio in case of positive rake angle. The results suggest that positive rake angled tools can make more plastic deformation and stable cutting of silicon nitride in comparison with negative rake angled one.

This paper reports on the theoretical and experimental study of the pressure ripples in a pressure unbalanced type vane pump which have widespread use in industry. Because they can infinitely vary the volume of the fluid pumped in the system by a control. Pressure ripples occur due to the flow ripples induced by geometry of side plate, leakage flow, reverse flow from the outlet volume produced by pressure difference between pumping chamber and outlet volume when the pumping chamber connected with the outlet volume. In this paper, we measured the pressure variation of a pumping chamber, reaction force on a cam ring, the mathematical model for analyzing the pressure ripples which included vane detachment and fluid inertia effects in notch area has been presented, and was applied to predict the level and the wave form of the pressure ripples according to operating conditions.

A 3-0 rehabilitation robot system is developed in this paper. The robot system is for the rehabilitation of upper extremities, especially the shoulder and elbow joints, and has 3-0 workspace for enabling occupational therapy to recover physical functions in activities of daily living(AOL). The rehabilitation robot system, which is driven by actuators, has 1 OOF in horizontal rotational motion and 2 OOF in vertical rotational motion, where all actuators are set on the ground. Parallelogram linkage mechanisms lower the equivalent inertia of the control elements as well as control forces. Also the mechanisms have high mechanical rigidity for the end effector and the handle. Passive motion mode experiments have been performed to evaluate the proposed robot system. The results of the experiments show and excellent performance in simulating spasticity of patients.

The purpose of this paper is to accomplish the stable humanoid robot walking on the soft terrains. The goal of the humanoid robot development is to make the robotic system perform some tasks in human living environment. However, human dwelling environments are very different from those of laboratories, where varied experiments are performed by the robot. In many cases, the ground is soft or elastic unlike the floor of a laboratory. When a robot walks on the soft ground, the sale of robot contacts the uneven ground. This results in unstable walking or walking may be impossible according to the degree of softness. Therefore, the algorithm that facilitates stable walking on the soft ground surface is required. In this paper, we suggest an algorithm that controls the ankle to help the robot walk stably on the soft ground using the humanoid robot (ISHURO-Ⅱ) as a real model. A humanoid robot walking on the soft ground was simulated to verify that the proposed algorithm results in stable walking.

Pneumatic cylinder is one of the low cost actuation sources which have been applied in industrial and prosthetic application since it has a high power/weight ratio, a high-tension force and a long durability. However, the control problems of pneumatic systems, oscillatory motion and compliance, have prevented their widespread use in advanced robotics. To overcome these shortcomings, a number of newer pneumatic actuators have been developed such as McKibben Muscle, Rubber Actuator and Pneumatic Artificial Muscle (PAM) Manipulators. In this paper, one solution for position control of a robot arm, which is driven by two pneumatic artificial muscles, is presented. However, some limitations still exist, such as a deterioration of the performance of transient response due to the changes in the external load of the robot arm. To overcome this problem, a switching algorithm of the control parameter using a learning vector quantization neural network (LVQNN) is proposed in this paper This estimates the external load of the pneumatic artificial muscle manipulator The effectiveness of the proposed control algorithm is demonstrated through experiments with different external working loads.

Because of both precise measurement and efficient quality control, coordinate measuring machines(CMMs) have been widely used in the industry. The purpose of this paper is to present a method to estimate the CMM measurement uncertainty using design of experiments. A factorial design is applied to carry out the performance test proposed by ISO 10360 and to investigate CMM measurement errors associated to orientation and length of the length bar. In order to assess the measurement uncertainty for the performance test, an analysis of the uncertainty components that make up the uncertainty budget has been carried out. The procedure for evaluating the uncertainty of it follows GUM ("Guide to the expression of uncertainty in measurement"). The results show that the proposed method is suitable to investigate CMM performance and determine the contribution of machine variables to measurement uncertainty.

The current tendency toward light weight and fast machines has lead to a need to suppress vibration of flexible dynamic systems. Input shaping is an efficient tool to eliminate transient and residual vibration caused by motion of these systems. This paper proposes a new formulation of the design method for multi-mode input shapers to eliminate residual vibration in flexible dynamic systems. The essence of the proposed method is to minimize the number of impulses to be n+1 for n-mode input shapers. This paper also suggests a solution procedure to solve the complexvalued nonlinear matrix equation for the input shapers. The proposed method is applied to twomode input shapers. This paper discusses characteristics of several input shapers obtained under the same condition. Simulations and experiments show that the proposed method is very useful for designing multi-mode input shapers.

In this paper, we studied of measurement the vibration of natural frequency using optical fiber sensor. The boring bar for measurement of vibration in use optical fiber sensor has the advantage of direct measure for the frequency than accelerometer. Because it deal with output value on electrical signal of optical fiber in physical disturbance when it measures the frequency of vibration. The optical fiber sensor measured the vibration of boring bar by the gap in sensing jig while optical fiber just kept contact with boring bar. A prototype system was composed of jig part with gap and optical system part. In this paper, we found out the possibility to measurement of vibration by the gap in use optical fiber.

In this research, heat-acupuncture needle was coated with Al₂O₃ by applying a plasma spray coating method to prevent a skin burn. Al₂O₃, which is one of the representative bioceramics, does not have an influence on the chemical change in the body system. The ceramic coating thickness was about 100 μm. The experiments of heat conduction were performed for uncoated needle and coated needle. The results showed that the surface temperature of needle decreased as the needle was coated with Al₂O₃. The surface temperature of uncoated needle was about 48°C, while that of needle coated with Al₂O₃ was about 39°C.

Spindle units of machine tool are very important part in the manufacturing area. Recently high speed machining has become the main issue of metal cutting. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Due to increase of the rotational speed of the spindle, there has been renewal of interest in vibration of spindle. This paper concerns the improvement of spindle design using design of experiments. To improve the design of critical speed and weight of spindle, the experiments using central composite method have been carried out. The targets are critical speed and weight of spindle. For optimization of critical speed and weight and optimization of only critical speed by operation of all area search through response optimizer, the result of analysis has improved design of each factor. Finite element analyses are performed by using the commercial codes ARMD, CATIA V5 and ANSYS workbench. From the results, it has been shown that the proposed method is effective for modification of spindle design to improve critical speed and weight.