Shun Ushida

Successive wide viewing angle appearance manipulation with dual projector camera systems

In this study, we investigated the use of successive omnidirectional appearance manipulation for the cooperative control of multiple projector camera systems. This type of system comprises several surrounding projector camera units, where each unit projects illumination independently onto a different aspect of a target object based on feedback from the projector cameras. Thus, the system can facilitate appearance manipulation from any viewpoint in the surrounding area. An advantage of this system is that it does not require information sharing or a geometrical model. However, this approach is problematic because the stability of the total control system cannot be guaranteed even if the feedback system of each projector camera is stable. Therefore, we simulated the feedback from the cooperative projector camera system to evaluate its stability. Based on hardware experiments, we confirmed the stability of omnidirectional appearance manipulation using two projector camera units in an interference condition. The results showed that the objects appearance could be manipulated throughout approximately 296 degrees of the total circumference of the target object.

Control performance improvements due to fluctuations in dynamics of stochastic control systems

Human motor control mechanisms are distinguished by two remarkable properties: time delays and random fluctuations. In this work, we focus on these two properties and investigate the effects of fluctuations on the stability and behavior of a stochastic linear time-delay system. The control performance improvements due to fluctuation are presented using numerical simulations as well as its theoretical analyses. In conventional controller design, a random component such as fluctuation is targeted for removal from the system as a factor causing performance reduction. However, the results presented in this paper suggest that an appropriate fluctuation component in control systems can help to achieve better control performances.

MIMO Closed-Loop Subspace Model Identification and Hovering Control of a Coaxial Mini Helicopter with 3 DOFs

Abstract This paper reports the experimental results of the dynamic modelling using MIMO closed-loop system identification, controller design and implementation for hovering flight of a coaxial radio-controlled helicopter. The helicopter is set on our handcrafted supporting device, and it has the roll, side-to-side and up-and-down motions. The maneuvers are done by the aileron and the throttle. Hence, our system is with 2 inputs and 3 outputs. A dynamic model is derived for hovering flight conditions from closed-loop system identification experiments with the MOESP-type closed-loop subspace model identification method (CL-MOESP). Then, LQR with a full state observer is designed and implemented.

Adaptive modeling and compliance control for RC servo motor

This paper concerns compliance motion control for joints of a humanoid robot for the external force. Our strategy is to estimate the amount of the external force by measuring the motor drive current of the RC servo motor since auxiliary current sensors can be attached easily. However, we did not consider about the dynamics of RC servo motor. The aim of this paper is to propose the adaptation scheme to identify the dynamics model of RC servo motor. We construct a time-varying adaptive identifier of the parameters with adaptation law based on adaptive control theory and give successful results in our numerical simulation.

Optimization on lens contour data with measurement error for the lens edger

In this paper, we focus on optimization problem of a lens contour data for high precision in the lens edger. When the lens edger recognizes a lens contour, the measurement error in the lens contour data appears due to some factors. In this paper, we modify the lens contour data to suitable one to grind lens based on nonlinear optimization scheme, which realizes higher precision and quality of lens shape data in the lens edger system.

Closed-loop subspace model identification of dual-rate systems with input fast sampling

In this paper, we consider closed-loop identification for an unstable dual-rate system with the sampling period of the output being an integral multiple of the hold period of the input. Using the well-known lifting technique, the relation of a stack of the succeeding input samples to the output, i.e., the lifted model, is estimated using CL-MOESP, which is a closed-loop subspace model identification method. Finally, a numerical example illustrates the effectiveness of the proposed closed-loop identification method to the lifted model.