A stabilization strategy of rotary cranes has been proposed in this paper. Since the linearized system of the rotary crane becomes uncontrollable for radial motion, nonlinear control is required. An easy algorithm can be found for stabilizing the load at the specified position by moving the boom at each half periods of the load swing. The effectiveness of the proposed method has been shown by simulations and experiments.
A method of levitation control of an induction-type motor is proposed. It is assumed that the stator has a current sheet which can produce an arbitrarily distributed magnetic flux, while the rotor is assumed to have a uniform magnetic property where the induced current is produced of the same form as that of the rotor magnetic flux. The levitation force can be produced and controlled by a proposed ±2 pole algorithm. A horizontal experimental apparatus is fabricated to validate the proposed method. In this paper, the load torque and the radial force capability are tested using a torque test apparatus and the rotor gravity as the radial load. The results obtained are discussed in detail.
Two-legged hopping robot has been developed, and its control has been studied. The robot is composed of a four-linkage crank mechanism and a parallel linkage mechanism. Efficient movement of both legs for higher jumping height has been obtained by simulation, and experiment has been pursured.
We have proposed a posture control method for a hopping robot. Feedback gains for flight and stance modes are obtained by solving a certain optimization problem for the posture stabilization. The robot has a crank mechanism and hip drive mechanism.
Hybrid magnetic bearing is recognized as an efficient one even with wide airgap and is suitable for such application. Previously sub-pole type IPM hybrid magnetic bearing has been proposed. However the sub-pole produces bias flux and cannot produce control force. To overcome this problem, two new types of hybrid magnetic bearings are proposed which have permanent magnet within the stator core. This paper introduces structure and principle of the proposed magnetic bearings. The geometric parameters of these new type mechanisms are optimized by FEM analysis. The experimental setups are made based on these analytical results. The fundamental characteristics are measured and compared with the estimate bearing performances. The results show stable levitation and good rotated levitation.
This paper describes the standing stabilization for people with a disability in lower limbs wearing an exoskeletal robot. There is a problem that people with a disability in lower limbs do not have sense of sole which is important for maintaining standing posture. Zero moment point or center of gravity are presented to the subject using visual and tactile method. As for tactile method, experiments are conducted for various skin part and various distance of adjacent solenoid pins of the tactile device.
This paper is concerned with the method of stabilizing the posture of a hopping robot. The conventional stabilizing method is to feedback the instantaneous state of the current mode: the flight mode or the stance mode. We have proposed the hybrid control law that feedbacks the final state of the previous mode as well as the state of the current mode. It is shown by simulation that we can improve the maneuverability of characteristic eigenvalues and the stability of the hopping robot by the proposed method.
New six pole type hybrid magnetic bearing is introduced. It is intended to apply to high speed turbo-machinery. Traditionally turbo-machinery uses standard electromagnet (EM) type active magnetic bearing (AMB) which requires PWM power amplifiers. Recently turbo manufacturers want to develop their own magnetic bearing. Sometimes they are not accustomed to developed standard EM type magnetic bearings. The proposed magnetic bearing uses bias Permanent Magnet (PM), hence it is easily manufactured. The developed magnetic bearing also has good characteristics due to six directional control pole compared with the standard four directional control one. An experimental setup is fabricated and tested with good results. Finally auto balancing control is applied to the free side of proposed magnetic bearing.
