Development of a robotic fish using electrostatic film motors: the Seidengyo II robot

We previously built a fish-like robot named Seidengyo I (based on the Japanese words for electrostatic (seiden) and fish (gyo)), which is a light and flexible robot actuated by a novel electrostatic film motor. This paper describes the design features that underlie the operation of Seidengyo II, which is an evolutional prototype of Seidengyo I. These features include an elaborate three-layer electrostatic film motor, a unique power transmission system and a compact robot controller. The power transmission system permits reciprocating power from the three-layer electrostatic actuator to be converted to periodic oscillations of a caudal fin. The robot controller is capable of easily generating high-frequency and high-voltage driving signals. As a result, we can control the oscillations of the caudal fin of Seidengyo II via synchronous operation to achieve open-loop swimming. We present the experimental results regarding the performance of the constructed controller and verify the validity of the design of the Seidengyo II robot by these experimental results.     

High-speed visual servoing of a 6-d.o.f. manipulator using multivariable predictive control

This paper presents a new approach to model and control high-speed 6-d.o.f. visual servo loops. The modeling and control strategy take into account the dynamics of the velocity-controlled 6-d.o.f. manipulator as well as a simplified model of the camera and acquisition system in order to significantly increase the bandwidth of the servo loop. Multi-input multi-output generalized predictive control (GPC) is used to optimally control the visual loop with respect to the proposed dynamical model. The predictive feature of the GPC is used for optimal trajectory following in Cartesian space. Experimental results on a 6-d.o.f. industrial robot are presented that validate the proposed model. The visual sensor used in the experiments is a high-speed camera that acquires 120 non-interlaced images. Using this camera, a sampling rate of 120 Hz is achieved for the visual loop. Furthermore, a precise synchronization method is used to reduce the delays due to image transfer and processing. The experiments show a drastic improvement of the loop performance with respect to more classical control strategies for 6-d.o.f. visual servo loops.     

Kinematic analysis of a translational 3-d.o.f. micro-parallel mechanism using the matrix method

In this paper, we applied the matrix method to kinematic analysis of our translational 3-d.o.f. micro-parallel mechanism for an instance of general flexure mechanisms. The matrix method has been well developed in architecture to analyze frame structures. We found that this method is well suited to such a flexure mechanism with circular notched hinges as our micro-parallel mechanism because it can be approximated to a Rahmen structure. Our matrix method can calculate a compliance matrix with less matrix nodes than the conventional finite element method. First, the compliance matrices of a circular notched hinge and some other beams are defined, and the coordinate transformations of the compliance matrix are introduced. Secondly, an analysis of our micro-parallel mechanism is demonstrated.     

TORSO: Development of a Telexistence Visual System Using a 6-d.o.f. Robot Head

In telexistence master–slave systems, it is important to transmit visual information from remote places to the operator. Conventional imaging devices in head-mounted displays (HMDs) can only express the three-axis rotation of the neck. However, humans can obtain broader visual fields and motion parallax information from the translational motion of their necks. We have proposed a system that can acquire natural and comfortable visual information, and can accurately track the head motion of a person. Our proposed device can express the head motion and the translation movements of the neck. We have developed a robot, called 'TORSO', and constructed a telexistence visual system with a display device, HMD. In this paper, by means of a broader field of view achieved by motion involving looking around, we demonstrate the advantage and novelty of our proposed system. In addition, we suggest the evolution of the TORSO–HMD system.     

Inverse Dynamics Analysis of a 4-d.o.f. Parallel Robot H4

This paper addresses the inverse dynamics of a 4-d.o.f. parallel robot, H4. Simplified inverse dynamics models have been proposed so far in which the inertia of a rod is neglected. Computation of the inertia of the rod was a heavy load for past computers and, hence, the simplified inverse dynamics were useful for online computation. However, owing to the recent great progress in computer hardware, online computation of the full dynamics is no longer a heavy load for modern computers. Therefore, a detailed inverse dynamics model of H4 is proposed in this paper. The Newton–Euler method is adopted for generating inverse dynamics solutions for H4 which have four (S–S)₂ (two spherical–spherical) chains in each rod. In order to evaluate the proposed inverse dynamics model, three controllers are tested: (i) PD controller, (ii) PD controller with velocity feed-forward and (iii) dynamic compensation controller based on the proposed dynamics model. The experimental results are presented and analyzed. It is also shown that the simplified dynamics model can be used without clear deterioration of control quality.     

Dynamic Formulation and Performance Evaluation of the 6-d.o.f. Parallel Structure Seismic Simulator

This paper presents the dynamic formulation and performance evaluation of the 6-d.o.f. parallel structure seismic simulator. By means of the principle of virtual work and the concept of link Jacobian matrices, the inverse dynamic model of the seismic simulator is set up. Then, a series of new dynamic performance indices with obvious physical meanings have been proposed. The dynamic performance index combining the acceleration, velocity and gravity terms of the dynamic equations has been achieved by decoupling the inverse dynamics in an exhaustive way. By using the index, it is possible for us to evaluate the performance in different directions. The index has been applied to the dynamic characteristic evaluation of the 6-d.o.f. parallel structure seismic simulator in the numerical simulation. Conclusions and results are provided at the end of the paper.     

Sensing of 2-chloroethyl ethyl sulfide (2-CEES) – a CWA simulant – using pure and platinum doped nanostructured CdSnO3 thin films prepared from ultrasonic spray pyrolysis technique

Nanostructured perovskite CdSnO₃ and Pt-CdSnO₃ thin films were prepared using ultrasonic spray pyrolysis technique. The nozzle (driven by ultrasonic frequency of 120 kHz) fixed on microprocessor controlled motorized arm could move in X–Y direction and spray onto heated (300 °C) glass substrate to give the films of repeatable thickness and microstructure. Structural and microstructural properties of the films were studied using X-ray diffraction and transmission electron microscopy (TEM), respectively. The sensing performance of the films was tested for CWA simulants, such as, CEES (2-chloroethyl ethyl sulfide C₄H₉ClS), DMMP (dimethyl methyl phosphonate C₃H₉O₃P) and CEPS (2-chloroethyl phenyl sulfide C₈H₉ClS). Both CdSnO₃ and Pt-CdSnO₃ showed higher response, better selectivity and faster speed of response to CEES as compared to their responses of DMMP and CEPS. CEES response of Pt-CdSnO₃ is larger than the response of CdSnO₃. The results are discussed and interpreted.     

Development of a dehydrogenase-based glucose anode using a molecular assembly composed of nile blue and functionalized SWCNTs and its applications to a glucose sensor and glucose/O2 biofuel cell

A simple and new way to immobilize glucose dehydrogenase (GDH) enzyme onto nile blue (NB) covalently assembled on the surface of functionalized single-walled carbon nanotubes (f-SWCNTs) modified glassy carbon (GC) electrode (GDH/NB/f-SWCNTs/GC electrode) was described. The GDH/NB/f-SWCNTs/GC electrode possesses promising characteristics as glucose sensor; a wide linear dynamic range of 100-1700 μM, low detection limit of 0.3 μM, fast response time (1-2 s), high sensitivity (14 μA cm⁻² mM⁻¹), anti-interference ability and anti-fouling. Moreover, the performance of the GDH/NB/f-SWCNTs/GC bioanode was successfully tested in a glucose/O₂ biofuel cell. The maximum power density delivered by the assembled glucose/O₂ biofuel cell could reach 32.0 μW cm⁻² at a cell voltage of 0.35 V with 40 mM glucose. The present procedure can be applied for preparing a potential platform to immobilize different enzymes for various bioelectrochemical applications.     

Development of a 42‐in. 2‐D/3‐D switchable display using multi‐view technology for public‐information‐display applications

Abstract— A 42‐in. 2‐D/3‐D switchable display operating in a parallax‐barrier‐type system consisting of liquid‐crystal displays (LCDs) has been developed. The system displays 2‐D images in full resolution, without any degradation to the original 2‐D images, and 3‐D autostereoscopic images with resolutions higher than SVGA with wide viewing zones electrically controlled by the parallax‐barrier system. The system is intended for use in public‐information displays (PIDs), a booming field, and as displays for gaming, medical, and simulation applications.