Ryou Kondo

H ∞ control problem with jΩ-axis zeros

Abstract In this paper we discuss the so-called one-block H∞ control problem in the case where the plant has jω-axis (including infinity) poles and zeros. First, we derive a necessary and sufficient condition for the H∞ model matching problem to have a solution in the transfer function setting. Second, we give a solvability condition which enables us to check the solvability by (i) examining matrix norm conditions related to jω-axis zeros and (ii) solving two generalized Riccati equations. Finally, we extend our result to the standard H∞ problem.

Development of Single Step Grinding System for Large Scale ϕ300 Si Wafer: A Total Integrated Fixed-Abrasive Solution

This research has developed an integrated manufacturing system for ϕ300mm silicon wafer, using fixed abrasive instead of conventional free slurry, to provide a totally integrated solution for achieving the surface roughness Ra < 1nm (Ry < 5∼6 nm) and the global flatness < 0.2μm/ϕ300mm. In addition to the space saving, this integrated system also significantly reduces the total energy consumption by 70%, compared with the current process used for ϕ200mm Si wafer. Three core technologies: the hybrid process mechanics, the GMM (giant magnetostrictive material) actuated positioning/alignment device and the ecologically friendly coolant circulation system are described in this paper. The system performance and results are then presented and discussed.

Characterization of discrete time H/sub infinity / controllers via bilinear transformation

A unified state space approach using bilinear transformation is proposed for continuous/discrete time H/sub infinity / optimal control problems. It is shown that Riccati equations and related factorizations of continuous time and discrete time systems can be formulated by the same Hamiltonian matrices. All H/sub infinity / sub-optimal compensators for continuous and discrete time systems are parametrized in a completely parallel way.<<ETX>>

Anti-sway control of a rotary crane via switching feedback control

A stabilization method of a rotary crane via switching control has been proposed in this paper. When boom motion is restricted to the rotation about the vertical axis, dynamics of the crane payload is a kind of non-holonomic system, and it cannot be stabilized by a smooth control law. We consider two linear systems which are linearized about different equilibriums. Each linearized system has an uncontrollable mode, but the union of controllable subspaces of those systems spans all the space. The basic idea of stabilization is that by switching the linearized system, the uncontrollable mode in one system can be settled in the other system using the energy control method. Furthermore, we have introduced an intermediate control step for making a transition of equilibriums to improve the final settling precision. The effectiveness of the method has been shown by simulation.

Proposal of Flux Concentrated Radial and Axial Magnetic Bearings

New flux concentrated hybrid (HB) type radial and axial magnetic bearings are proposed in this paper. It is intended to use ferrite permanent magnet (PM) for producing high bias flux. The capability of proposed magnetic bearings is confirmed using commercial FEM code “ANSYS”. The results show high possibility with less expensive PMs.

Wearable leg support system based on manual control

A wearable leg support system based on manual control has been proposed in this paper. Power assist suits, which are studied by many researchers lately, are not applicable to those people with lower limb paralysis caused by spinal cord injury or stroke. We have developed a wearable leg support system, Manipuleg-1, in which an exoskeletal leg support system is manually controlled with a control lever mounted on the normal side of shoulders. We will show that the wearer could walk if one made much practice and properly operated the control lever.

Energy Regenerative and Active Control of Automobile Suspension

A new energy regenerative and active control of automobile suspension is introduced. It is intended to improve vibration reduction capability using the regenerated energy. A PM type linear AC motor is used as an energy regenerative and active control suspension. This idea is applied to a quarter-car model and vibration control is performed. Energy regenerative and active control modes can not operate at the same time. A new control law is introduced to switch control modes and to follow the ideal force. The ideal force is calculated using the LQ control theory. The PWM switches are driven in proportion to the difference between the ideal control force and the actuator force using the modulation circuit. Experimental setup is made to confirm the proposed technique and the damping capability is tested.Copyright

Control of wire driven multi-link robot

The paper is concerned with the control of a multi-link robot driven by elastic wires. We have designed a servo controller to control the link angles and wire tensions to avoid the wire to loosen. Various simulations and experiments are given to show the effectiveness of the control.

Geometric Study of Space Motor and Power Assist Leg Motor

Generally, commercial motors are produced as the lineup of series of outer diameter. The output power is changed with their length. However, the production number of space motor or power assist leg motor is small, while the power ratio versus motor weight is very important factor. The geometric study is proposed in this paper; especially, such problems of outer rotor versus inner rotor motor, outer diameter versus length. The motor characteristics are assumed with the FEM simulation. These constants depend on the motor pole number and driving amplifiers. Hence the exact geometrical dimensions should be determined with the careful simulation. Before simulation rough geometrical size can be determined, then the exact simulation will be carried out to determine the motor dimension and estimate the produced motor characteristics. The results are planned to compare with some of the experimental results.

Proposal of Linear Oscillatory Actuator with Two Movers using Three Coils

Electromagnetic type linear oscillatory actuators are used in many devices because of high controllability and small size. In previous studies, a linear oscillatory actuator with two movers and two coils that effectively generates vibrations in a wide frequency range by impressing same-phase or reverse-phase current, is developed. However, two H bridge circuits are needed for driving the actuator. In this paper, a new actuator with two movers that can drive using a threephase inverter, are proposed. First, the characteristics of the proposed actuator are clarified by finite element analysis. Finally, there are compare with those of the conventional actuator.