Path tracking control of a manipulator considering torquesaturation

When the minimum-time trajectory of a manipulator along a geometrically prescribed path is planned taking into consideration the manipulator's dynamics and actuator's torque limits, at least one of the joints should be at the torque limit. The execution of such a trajectory by a conventional feedback control scheme results in torque saturation. Consequently, the tracking error cannot be suppressed and the manipulator may deviate from the desired path. In this paper, the author's propose a feedback control method for path tracking which takes the torque saturation into account. Based on the desired path, a coordinate system called path coordinates is defined. The path coordinates are composed of the component along the path and the components normal to the path. The equation of motion is described in terms of the path coordinates. Control of the components normal to the path is given priority in order to keep the motion of the manipulator on the path. Simulations of a two-degree-of-freedom manipulator show the effectiveness of this method     

Benign partial epilepsy with affective symptoms: hyperkinetic behavior during interictal periods

We report a 4-year-old boy with benign partial epilepsy (BPE) with affective symptoms associated with hyperkinetic behavior during interictal periods. He had had hypermobility and restlessness since about age 3. At 4 years, 6 months, he developed episodes consisting of an expression of terror without complete loss of consciousness. Although we first suspected an acute psychic problem, the ictal EEG was abnormal. After carbamazepine (CBZ) therapy, the frequency of the attacks decreased dramatically and the hyperkinetic behavior gradually diminished.     

Advanced microwave scanning radiometer (AMSR): requirements andpreliminary design study

An investigation on users' requirements for future passive microwave scanning radiometers, especially the advanced microwave scanning radiometer (AMSR), which is one of the Earth Observing System instruments, has been conducted together with a preliminary design of the AMSR system. As a result, mission parameters for the AMSR have been determined while the feasibility of the electronically scanning type of AMSR has been confirmed. In particular, it is found that a beam-switching antenna system that was developed makes possible multifrequency measurement, and multiple beam conical scanning, while preserving polarization purity     

Rheological behavior and microstructure of bimodal suspensions of core‐shell structured swollen particles

The rheological behavior and microstructure of bimodal suspensions of core‐shell structured swollen particles have been examined with changing volume ratio of two different sized particles. As the volume fraction of large particles increases, the viscosity, degree of shear‐thinning, and the critical shear stress σ_c decreases, while the interparticle distance ξ of the microstructure increases. The suspensions exhibit single mode rheological behavior and have a single diffraction peak in the SAXS profiles. These results suggest that the bimodal suspensions of the core‐shell structured swollen particles behave likely to unimodal suspensions of hard spheres with alloy like single mode microstructure composed of hypothetical intermediate size particle. The relationship between σ_c and ξ can be represented as σ_c = 3kT/4πξ³, which corresponds to the dynamics of the Brownian hard sphere model with ξ being the particle diameter. These findings indicate that the shear‐thinning of the suspensions can be attributed to dynamical competition between the thermal motion and the hydrodynamic motion under shear flow and that the mechanism can be applied to bimodal suspensions of the swollen particles as well as unimodal suspensions of hard spheres. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 102: 2212–2217, 2006     

Vision-based sensor for real-time measuring of surface traction fields

The desire to reproduce and expand the human senses drives innovations in sensor technology. Conversely, human-interface research aims to allow people to interact with machines as if they were natural objects in a cybernetic, human-oriented way. We wish to unite the two paradigms with a haptic sensor as versatile as the sense of touch and developed for a dual purpose: to improve the robotic capability to interact with the physical world, and to improve the human capability to interact with the virtual world for emerging applications with a heightened sense of presence. We designed a sensor, dubbed GelForce, that acts as a practical tool in both conventional and novel desktop applications using common consumer hardware. By measuring a surface traction field, the GelForce tactile sensor can represent the magnitude and direction of force applied to the skin's surface using computer vision. This article is available with a short video documentary on CD-ROM.     

Wilms' tumor suppressor gene (WT1) as a target gene of SRY function in a mouse ES cell line transfected with SRY

With the aim of identifying the gene(s) located downstream from SRY, we transfected an ES cell line with XX karyotype, TMA-18, with a Sry DNA construct and established cell lines, TS18-1 and TS18-2, where the transfected Sry was expressed in the functional linear mRNA form. Among the five potential SRY-target genes examined, i.e., MIS, SF1, P450arom, Sox9 and WT1, only the expression of WT1 was induced de novo by the unscheduled expression of Sry in the transfected cell lines. No clear indication of Sry-induced enhancement of Sox9 expression was obtained in the present series of experiments. Function of a yet unidentified gene(s) located on the Y chromosome might be needed for the up-regulation of Sox 9 expression which takes place during the development of male gonads. Quantitative RT-PCR analysis of the patterns of WT1 expression in developing fetal gonads revealed that although both male and female fetal gonads express WT1, male gonads invariably expressed WT1 mRNA at higher levels than female ones after the Sry expression. Immunohistochemical analysis of the male fetal gonads between 10.5 and 13.5 dpc demonstrated the presence of strong WT1 immunoreactivity in Sertoli cells of the primordial testes. Suggestions were made in the past indicating that both SF1 and WT1 proteins might be active in a common pathway upstream from Sry. Our results showed that WT1 is located downstream, rather than upstream from Sry and behaves independently from SF1. Analysis using an appropriate in vitro system will be essential to understand the molecular mechanisms of SRY action within cells.     

Development of anthropomorphic multi-D.O.F. master-slave arm for mutual telexistence

We developed a robotic arm for a master-slave system to support "mutual telexistence", which realizes remote dexterous manipulation tasks and close physical communication with other people using gestures. In this paper, we describe the specifications of the experimental setup of the master-slave arm to demonstrate the feasibility of the mutual telexistence concept. We developed the master arm of a telexistence robot for interpersonal communication. The last degree of the 7-degree-of-freedom slave arm is resolved by placing a small orientation sensor on the operator's arm. This master arm is made light and impedance control is applied in order to grant the operator as much freedom of movement as possible. For this development stage, we compared three control methods and confirmed that the impedance control method is the most appropriate to this system.     

Asymptomatic Becker muscular dystrophy: expression of dystrophin and dystrophin-related protein

We report a patient with systemic lupus erythematosus (SLE), who had developed metabolic alkalosis during plasmapheresis. The metabolic alkalosis could be promptly corrected by reducing the amount of citrate load. The development of metabolic alkalosis can be explained by the citrate load during plasmapheresis. Careful monitoring of acid base status is mandatory in patients with limited renal function and the reduction of citrate load may be advisable in plasmapheresis.     

Locations of crossover breakpoints within the CMT 1 A-REP repeat in patients with hereditary neuropathy with liability to pressure palsy--detection by recombinant chromosome-specific polymerase chain reaction

The "short Achilles tendon" syndrome, characterised by limited dorsiflexion of the tibiotarsal joint, is not well-known but could be a disposing factor for trophic disorders and plantar ulcer related to hypersupport in the diabetic subject. We report two cases of multicomplicated diabetic patients treated during several months for plantar ulcer superinfected with underlying osteoarthrits, whose course became rapidly favourable after tenotomy of the Achilles tendon. This simple surgical act can be performed in ambulatory conditions under local anaesthesia. Functional disability is negligible. The benefit of this treatment as part of the curative or preventive therapeutic arsenal for care of the diabetic foot remains to be evaluated.     

Measurement of internal stresses in coatings using time resolved fluorescence

This paper describes a new nondestructive technique for detecting internal stresses in coatings using time resolved fluorescence. The measurement principle is based upon an experimental result that the decay time of fluorescence from poly(3-octylthiophene), P3OT, dispersed in uniaxially-stretched polymer films decreases with increasing tensile stress acting on the films. Internal stresses in the clear coat and in the base coat of a multilayer structure, which was composed of electrodeposited coat, surface coat, base coat, and clear coat, were estimated from the decay time of fluorescence from P3OT in both coats. The order of internal stresses in the clear coat and base coat of the multilayer system was 1 MPa. When the coatings were piled up, the internal stress decreased as the distance from a metal substrate was increased. It was found that moisture and temperature influenced internal stresses in the clear coat rather than in the base coat. Internal stress in the clear coat, which was one layer coated on a metal substrate, was measured by the traditional bimetallic method or by the time resolved fluorescence technique. Comparing both methods, it was concluded that the time resolved fluorescence technique gave reliable values for internal stresses in coatings.