Abstract: In a technique of monitoring whether a physical system is normal or abnormal by continuously comparing a phenomenon taking place in the system and a phenomenon taking place in a model and also in a technique of control adopting evaluation functions using an error quantity in the model, the phenomena in both the physical system and model can be optimized. An equivalent electric circuit to the physical system is produced, and an input is provided to both of the system and the circuit. In this state, the output of the physical system and the reference value of the equivalent electric circuit are compared. The use of the equivalent electric circuit permits solving the problem inherent in the prior art that the time necessary for analog-to-digital conversion and numerical calculations is longer than the time of the actual phenomenon and disables real time simulation.

Abstract: A rotational actuator includes an actuator case, a first rotor supported on the actuator case for rotation about an axis of rotation, a second rotor supported on the actuator case coaxially with the first rotor and for rotation independent of the first rotor, an expandable member having one end secured to the second rotor and the other end secured to the first rotor for relatively rotating the first and second rotors by expansion or contraction thereof, and an expandable member controller for controlling the extent of expansion and contraction of the expandable member. The momentum of the first rotor in the rotational direction thereof when the expandable member is expanded or contracted is set to be higher than the momentum of the second rotor in the rotational direction thereof at this time.

Abstract: A stepping motor includes a stator and a rotor. The stator has pole teeth projecting from the inner surface at a constant pitch. The rotor has first through fourth rotor sections, and permanent magnets are embedded into the outer surface of each of the first through fourth rotor sections at a pitch equal to the pitch of the pole teeth. Two coils are provided in the stator so as to generate looped magnetic fluxes in the stator. A first offset corresponding to one half of the pitch of the permanent magnets is provided between each permanent magnet of the first rotor section and a correspond permanent magnet of the second rotor section, and a second offset equal to the first offset is provided between each permanent magnet of the third rotor section and a correspond permanent magnet of the fourth rotor section.

Abstract: It is difficult to use in combination a technique of detecting a collision of an arm due to application thereto of an external force and a technique of alleviating the degree of impact of the arm by covering the arm with a cushioning material. This is so because if it is intended to alleviate the impact degree, the timing of detection of the generation of the collision is delayed. The disclosed technique is to overcome the relation of the opposing factors by using a visco-elastic material. Particularly, by selecting the viscosity coefficient and the elasticity coefficient of the material in predetermined ranges, it is possible to alleviate the impact degree without excessive delay of the impact detection timing and forcibly stop the arm before the force acting between the arm and the object exceeds a permissible level.

Abstract: An induction motor capable of producing an increased torque has a stator for generating a rotating magnetic field, a stator fixed to a shaft, a cylindrical member disposed within an inner space defined by the rotor and rotatably supported by the shaft, and magnets attached to the circumference of the rotor such that the magnets face the rotating magnetic field. The induction motor may be provided with a mechanism for adjusting the effective magnetic force of the magnets. The magnets may be permanent magnets or electromagnets. Also, a synchronizing mechanism may be provided to prevent the cylindrical member from lagging behind the rotor. A linear induction motor includes a straight primary coil assembly and a straight secondary coil assembly. One of the primary coil assembly and the secondary coil assembly is movable relative to the other. Also, a plurality of magnets are disposed in the secondary coil assembly.