Teachingless spray-painting of sculptured surface by an industrial robot

金沢大学工学部The study deals with the automatic spray-painting by a 6-DOF industrial robot equipped with an air spray gun. Since the robot control commands generation for the spray-painting is manually performed by skilled workers using a teaching-playback function of a robot controller, the time, experience and patience are required. The study aims at making robot control commands without any special knowledge on spray-painting, in the case of bumpers of a car as an example of sculptured surfaces. The system can automatically generate a spraying path for the air spray gun on the basis of CAD date of the workpiece, and change the spraying path into robot control commands. From experimental results, the system is found to effective in painting bumpers of a car with an uniform paint thickness

Automation of chamfering by an industrial robot; for the case of hole on free-curved surface

金沢大学工学部The study deals with the automatic chamfering for the case of hole on free-curved surface on the basis of CAD data, using an industrial robot. As a chamfering tool, a rotary-bar driven by an electric motor is mounted to the arm of the robot having six degrees-of-freedom in order to give an arbitrary position and attitude to the tool. The robot control command converted from the chamfering path is transmitted directly to the robot. From the experimental results, the system is found effective to remove a burr along the edge of a hole on a workpiece with free-curved surface. © 2002 Elsevier Science Ltd. All rights reserved

Automation of chamfering by an industrial robot; for the case of machined hole on a cylindrical workpiece

金沢大学工学部The study deals with the automatic chamfering for the case of a machined hole on a cylinder on the basis of CAD data, using an industrial robot. As a chamfering tool, a rotary-bar driven by an electric motor is mounted to the arm of the robot having six degrees of freedom in order to give an arbitrary position and attitude to the tool. The robot control command converted from the chamfering path is transmitted directly to the robot. From the experimental results, the system is found effective to remove a burr along the edge of a hole on a cylindrical metallic workpiece

Dexterous Machining of Unstable Thin Plate

In recent years, miniaturization and light weightedness are required for industrial products as well as high functionality. Thin plates are appropriate in terms of weight, however they are usually difficult to produce only by cutting operation due to the deformation by cutting force or vibration of the thin plate. This study deals with the machining of a twisted thin plate, whose height, width and thickness are 50 mm, 30 mm and 0.1 mm respectively, without using any auxiliary tool. Such a thin plate with high aspect ratio is easily broken down by the cutting force. Thus, the machining of thin plate with high aspect ratio is approached by devising a tool path strategy in this study. As the cutting force easily allows for deformation of twisted thin plate with high aspect ratio, two methods are devised with regard to the generation of the tool path, the method with a supporting frame and the peeling method so that the stiffness of the plate can be kept high. Then, the actual machining of thin plate with high aspect ratio, made of aluminum alloy, was realized without any breakage. As a result, it is found that such cutting method allows the possibility of fabricating such a twisted thin plate

Contacts between the commissural axons and the floor plate cells are mediated by nectins

AbstractDuring development of the central nervous system (CNS), commissural axons grow toward the ventral midline. After crossing the floor plate, they abruptly change their trajectory from the circumferential to the longitudinal axis. The contacts between the commissural axons and the floor plate cells are involved in this axonal guidance, but their mechanisms or structures have not fully been understood. In this study, we found that nectin-1 and -3, immunoglobulin-like cell–cell adhesion molecules, asymmetrically localized at the contact sites between the commissural axons and the floor plate cells, respectively. In vitro perturbation of the endogenous trans-interaction between nectin-1 and -3 caused abnormal fasciculation of the commissural axons and impairment of the contacts, and resulted in failure in longitudinal turns of the commissural axons at the contralateral sites of the rat hindbrain. These results indicate that the contacts between the commissural axons and the floor plate cells are mediated by the hetero-trans-interaction between nectin-1 and -3 and involved in regulation of the trajectory of the commissural axons

Cast: a novel protein of the cytomatrix at the active zone of synapses that forms a ternary complex with RIM1 and munc13-1

The cytomatrix at the active zone (CAZ) has been implicated in defining the site of Ca2+-dependent exocytosis of neurotransmitter. We have identified here a novel CAZ protein of ∼120 kD from rat brain and named it CAST (CAZ-associated structural protein). CAST had no transmembrane segment, but had four coiled-coil domains and a putative COOH-terminal consensus motif for binding to PDZ domains. CAST was localized at the CAZ of conventional synapses of mouse brain. CAST bound directly RIM1 and indirectly Munc13-1, presumably through RIM1, forming a ternary complex. RIM1 and Munc13-1 are CAZ proteins implicated in Ca2+-dependent exocytosis of neurotansmitters. Bassoon, another CAZ protein, was also associated with this ternary complex. These results suggest that a network of protein–protein interactions among the CAZ proteins exists at the CAZ. At the early stages of synapse formation, CAST was expressed and partly colocalized with bassoon in the axon shaft and the growth cone. The vesicles immunoisolated by antibassoon antibody–coupled beads contained not only bassoon but also CAST and RIM1. These results suggest that these CAZ proteins are at least partly transported on the same vesicles during synapse formation