It is a basic need for robot teaching not to stop production lines while robots are taught their movements. To realize this off-line teaching it is important to check up on teaching data not to cause interference between robots and objects in working environment. This paper proposes an interference check method based on the idea of minimum distance between a robot and an object. This method is aimed at being implemented mainly on workstations at production sites rather than on large computers in design rooms, and so it is required to use less memories and calculation time than most of the past methods do. In this paper, first, classification of the interference is given from the viewpoint of approximated shapes of robots and objects which includes rectangular columns, circular cylinders, plane patches and so on. Next, this method is given concrete forms in regard to several kinds of the interference between these approximated shapes which used to be difficult to find out immediately. Finally, this method is evaluated by comparison with another method and has been estimated to be one seventh in calculation time.

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The servo-actuator using shape memory alloy, or SMA actuator, has the potentioal capability to be developed into novel Robot actuator. The paper discusses the fundamental problems and their solves to realise practical SMA actuator. First of all, it is pointed out that the SMA actuator can be an actuator with high output weight ratio, because the shape memory alloy is based on martensitic transformation of the material itself. To the contrary, it is shown that the SMA actuator is limited in its energy efficiency and response velocity because it is regarded as the low temperature difference thermal engine.
Some of these disadvantages is then shown to be eliminated by the introduction of a specific design method of SMA actuator. It is called c-array, which arrays the SMA wire in parallel and connects serially as a electric circuit. The a-array increases SMA's surface area and the electric resistance. Thus it enables the following characteristics, i) comparatively fast response time, ii) minimization of the diameter of lead wires which supply electricity from power unit, iii) feasibility to use commercially available high voltage low current power unit, iv) possibility of the positive use of SMA's electric resistance change as a feedback signal of servo control. Finally these considerations are verified by the experiment of the SMA actuator model.

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When an industrial robot grinds a curved surface of a workpiece, an operator must accurately teach the configuration of the surface. This teaching, however, is a very troublesome job because of the large number of the teaching points.
This paper proposes a teachingless grinding robot to save that trouble. This robot system consists of a manipulator mounted a cylindrical grindstone on the end-effector, instruments to measure the three different forces and a computer equipped with an AD converter. One of the force informations is a grinding torque, and the others are the two components of a grinding force which is applied to the grindstone from the workpiece. The coordinates of the points where the grindstone contacts with the workpiece is calculated from these force informations by the computer. Therefore, the robot is able to recognize the contour of the workpiece and to grind it without teaching. The experiments using an articulated robot arm with five degrees of freedom show that the proposed robot system is applicable to the grinding of the continuous curved surface of a workpiece.

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Pantograph mechanisms for force generation called PMFG are proposed. The mechanisms are based on four-bar linkage mechanisms and are effective in energy saving, simplification, and miniaturization of a total system of force generation. Static relationship between the motion of the mechanism and its output force is analyzed for optimization of structure and dimensions. For optimization of pulley shapes, analytical and approximate methods are discussed. Experimental results show that eccentric non-circular pulleys are more effective than the circular pulleys in producing accurate force to satisfy conditional relations between the force and displacement of mechanism. The mechanism is useful in fulfilling various kinds of force versus displacement characteristics requirements.

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Metal hydrides can absorb and desorb hydrogen in reversible reaction by heating or cooling the hydrides. We have developed an actuator consisting of metal hydrides covered with a copper case (23mm diameter, 6mm hight), Peltier elements (38mm×38mm×5mm) to heat or cool the hydrides and a cylinder (46mm diameter, 73mm hight) with metal bellows.
From the experimental results, it was found that the velocity of hydrogen absorption was faster than the desorption, however, its velocity increased as the weight of load on the cylinder increased. The actuator could produce the one stroke displacement of 25 mm within 50 sec in the case of 22.5kg load weight.

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