Toshiki Suzuki

The design method of two-degree-of-freedom controller using /spl mu/-synthesis and its application to two-mass system

This paper presents the design method of two-degree-of-freedom (2 dof) controller system based on the internal structure Firstly, we show the internal structure of the system and derive the condition which clearly shows the equivalence between the disturbance observer based controller and the generalized 2 dof controller. Secondly, we propose the design method of free parameter using /spl mu/-synthesis taking into account the structure of the system and the tuning of the Q so as to satisfy the derived conditions. Finally, we show some simulation results of velocity control of a 2-mass system and confirm the effectiveness of the proposed method.

The design method of two-degree-of-freedom controller using /spl mu/-synthesis

This paper presents the design method of a two-degree-of-freedom (2 DOF) controller system based on an internal structure. The authors show the internal structure of the system and derive the condition which clearly shows the equivalence between the disturbance observer based controller and the generalized 2 DOF controller. They then propose the design method of free parameters using /spl mu/-synthesis taking into account the structure of the system and Q tuning so as to satisfy the derived conditions. Finally, the authors show the simulation results of velocity control of a 2-mass system and confirm the effectiveness of the proposed method.

Improvement in response of position estimation for IPMSMs in low-speed regions including standstill using area calculation

This paper proposes a direct rotor-position estimation method for IPMSMs (Interior Permanent Magnet Synchronous Motors) in low-speed regions including standstill. Proposed estimation method does not require phase-locked-loop (PLL) which degrade the response of position estimation and it can improve the response of position estimation.

Evaluation of direct position estimation based on α-β axes inductance information for IPMSM sensorless control systems

This paper proposes a direct rotor-position estimation method for IPMSMs (Interior Permanent Magnet Synchronous Motors) in low-speed regions including standstill. In general, the rotor position is estimated indirectly by converging the position estimation error into 0 by the phase-locked-loop (PLL). The indirect rotor position estimation methods require the convergence time of position estimation error. On the other hand, the proposed direct rotor estimation method does not require a phase-locked-loop (PLL), which degrades the response of position estimation. The proposed method has possibilities of improving the position estimation response. This paper demonstrates the performance of sensorless control based on proposed direct position estimation.

Initial position estimation for IPMSMs using comb filters and effects on various injected signal frequencies

This paper proposes fast initial position estimation of IPMSMs (Interior Permanent Magnet Synchronous Motors), which is based on intentional pulse voltage injection and comb filters. Most initial position estimation methods utilize the amplitude or differential values of high-frequency currents and the performance of sensorless control depends on the algorithm to reconstruct these values. Although Fourier series expansion which requires some Low-Pass Filters(LPFs) is utilized in general, the filters degrade the response of position estimation. This paper focuses on the algorithm for initial position estimation of IPMSM at standstill, and proposes a new algorithm using comb filters which can rapidly calculate amplitude values of high-frequency currents and can improve the initial position estimation performance. In addition, this paper experimentally shows the performances of the initial position estimation, starting characteristics of sensorless control and characteristics of sensorless control including standstill under the load.

Fast initial position estimation for IPMSMs at standstill using comb filters

This paper proposes the fast initial position estimation of IPMSMs (Interior Permanent Magnet Synchronous Motors), based on intentional pulse voltage injection and comb filters. Generally, the rotor position can be estimated by detecting high-frequency current caused by injected high-frequency voltage because its response includes inductance information due to saliency. In general, sinusoidal current, sinusoidal voltage and pulse voltage are utilized for saliency excitation. Methods based on sinusoidal current and voltage, however, require a shorter control period for precise signal injection, making methods based on pulse voltage injection more desirable. Methods based on pulse voltage injection generally utilize the amplitude or differential value of high-frequency current. The algorithms used to calculate the currents amplitude or differential value, however, are complex and unsuitable for improving the response of position estimation. Especially, algorithms for calculating amplitude values require low-pass filters (LPFs), with the low cut-off frequency utilized for the amplitude calculation. This process degrades the response of the initial position estimation. In order to overcome this problem, this paper proposes a new algorithm using comb filters which can rapidly calculate the amplitude value of high-frequency current and improve the initial position estimation performance.

Fault tolerant flight controller design using /spl mu/-synthesis for the unmanned winged re-entry space vehicles

Unmanned winged re-entry space vehicles glide without any thrust in their re-entry phase. In this phase, one of the most possible and important faults in the airframe is jamming of the elevon. In order to make control systems tolerant to this failure, the flight control system is required to keep its stability and the performance, even if such a failure occurs. Since this kind of fault can be modeled as a structured parameter deviation from a robust control point of view, this paper presents some new ideas to realize a fault tolerant flight control system based on /spl mu/-synthesis, and apply it to the unmanned winged re-entry space vehicle HOPE-X (H-II Orbiting Plane-Experimental). Simulations are also demonstrated to verify the usefulness of the proposed method.

Switching of H/sub /spl infin// controller under existence of constraints on state variables

In real control systems, there are some constraints on the value of inputs, states and outputs. If such constraints are violated, systems may become unstable as the worst case scenario. One of the promising approaches to solve this problem is to switch the controller according to the state of the closed loop system. No useful design strategy for each controller, however, has been developed yet. In addition, the decision of controller state at the instance of controller switching has not been investigated. First of all, this paper presents a new design methodology which merges the switching control and H/sub /spl infin// controller design into one design algorithm. Secondly, this paper presents a way to decide the controller states at the instance of controller switching. Finally, the proposed method is applied to a force control of one DOF manipulator to demonstrate the usefulness of the proposed method.