Satoko Yamakawa

The necessary conditions of the scaling ratio in master-slave systems based on Human Difference limen of force sense

In the use of master-slave systems designed ignoring human perception abilities, there are threats of missing or misunderstanding important information because the range of the displayed information may be unsuitable for the perception abilities of the operator. Therefore, we aim at incorporating human perception abilities into the necessary conditions for designing the scaling methods in master-slave systems. This work focuses on one of the inner characteristics of force perception, namely the difference limen. Taking account of the well-known Webers law, we assume that the difference limen is described as a linear function of the standard stimulus. Then, in general, we derive the necessary conditions of scaling methods to recognize changes of stimuli generated on the slave side. Simultaneously, the lower limit of the scaling ratio is clarified. The difference limen at fingertips is measured for constant, elastic, and viscous forces, which are typical force elements. The obtained measurement results confirm the previous assumption of linear dependency. Finally, we conclude with discussions of the necessary conditions based on the measurement data with variations.

Adaptive visual tracking of moving object with neural-PID controller

In this paper, an adaptive approach is presented to nonlinear system for real-time robotic visual tracking of a moving polyhedral object. A light stripe vision system consists of a laser-stripe sensor and a CCD camera fixed to robot end-effector, and projects planar light on the polyhedral object. The geometric conditions can be provided to assure location of features of the polyhedral faces. The objective is to predict the location of features of the object on the image plane based on the light stripe vision system and then to determine an optimal control input that will move the camera so that the image features align with their desired positions. We first give the equations of observation and stat-space by using the motion rules of the camera and the object. Then, the system can be represented as an MIMO ARMAX model and an efficient estimation model. The estimation model can process on-line estimation of the 3D related parameters between the camera and the object. Those parameters are used to calculate the system sensitivity of a neural network. The control scheme adopts a neural-PID controller that can adjust the PID controller parameters. The paper concludes with the simulation results and the compute stimulation shows that the proposed method is effective to visual tracking of combining vision and control

An Interactive Approach to Fuzzy-based Robust Design

In order to win in the violent global competition, it is necessary for vendors to shorten the product development of novel, better product on quality consideration. It is expected to be an efficient way to extend robust design to the early stage of design. In this paper, we define multiple aspects of robust design from the view of multi-objective optimization. For the existing two problems in related researches, a new robust design model is proposed and embedded into an interactive approach as a decision making procedure. Fuzzy LR Number is used in this model to deal with asymmetric distributed variables and capture the imprecision in design variables in the early phases of design. Assisting by the proposed approach in which a proposed reference mechanism is embedded, designer is available to use progressively generating preference structure to select satisfactory solution from the optimized Pareto solution set. Pressure vessel design is used as an example to demonstrate the proposed approach.