A self-bearing motor (SBM) is an electric motor with a magnetically integrated bearing function, that is, it can provide levitation and rotation simultaneously as a single actuator. This paper presents the design, operating principle and control system for the slotless self-bearing motor (SSBM). In this design, the stator has no iron core but includes six-phase coils. The rotor consists of a permanent magnet and an enclosed iron yoke. Magnetic forces generated by the interaction between stator currents and the magnetic field of the permanent magnet are used to control the rotational speed and radial position of the rotor. In this paper, the torque and radial bearing forces are analyzed theoretically with the aim to develop an improved control system. In order to confirm the proposed control method, an experimental system was constructed and tested. Simulation and measurement results show that the SSBM can work stably in modes such as start, reverse, rotation load and external radial pulse forces.

This paper discusses the stability of a tilt-controlling axial gap self-bearing motor with a single stator. The motor consists of a stator and a disc rotor and is capable of controlling motor torque, axial position, and tilt angles. The stator has six coils, which are driven by separate amplifiers. By adding two types of current (a motor current, which has the same poles as the rotor, and a tilt control current, which has plus two or minus two poles of the rotor), four degrees of freedom of the rotor can be actively controlled. In this paper, the motor torque, axial force, tilt torques, and radial forces are theoretically analyzed and their control methods of them are derived. The stability of the rotor is discussed and the influence of the position of the center of gravity is shown. The experimental results confirm the analytical results, and it is shown that the stable levitation and rotation are achieved with 2-pole and 4-pole rotors.

In this paper, a method to posture maintenance control of 2-link object by nonprehensile two-cooperative-arm robot without compensating friction is proposed. In details, a mathematical model of the 2-link object is firstly built. Based on the model, stable regions for holding motion of nonprehensile two-cooperative-arm robot are obtained while the 2-link object is kept stable on the robot arms with static friction. Among the obtained stable regions, the robust pairs of orientation angles of the 2-link object are found. Under the robust orientation angles, a feedback control system is designed to control the arms to maintain the 2-link object's posture while it is being held or lifted up. Finally, experimental results are shown to verify the effectiveness of the proposed method.

In this paper, a new model of magnetically levitated (Maglev) vertical axis wind turbines (VAWTs) is presented for power generation purposes. The rotor is suspended by two permanent magnet attractive type passive magnetic bearings and one control coil; it is possible to rotate the rotor without any mechanical contact. The proposed model solves the most common problems which are found on the other Maglev VAWTs such as reducing the power consumption during the levitation to zero amperes by the zero-power control method and reducing rotation loss during rotation. In addition, the model has some main advantages consisting in the ability to avoid the resonance at the critical speed and increase the maximum rotation speed by changing the air gap between the rotor and passive magnetic bearings to adjust the radial stiffness of the rotor. The design of the passive magnetic bearings is investigated by the finite element analysis, and the optimum shape is discussed. The results of levitation tests are presented for the model to show the effectiveness of levitation current reduction and the adjustment of radial stiffness. The results of rotation tests show that the resonance can be avoided by changing the radial stiffness which also makes it possible to rotate the rotor over the critical speed. Moreover, the results of free-run tests show that the rotation loss of the proposed Maglev system is quite low.