Satoshi Ohdaira

Brief paper: Adaptive output feedback control of general MIMO systems using multirate sampling and its application to a cart-crane system

In adaptive output feedback control based on almost strictly positive real conditions, a technical difficulty arises when the multi-input multi-output (MIMO) system under consideration is non-square, and in particular, has less inputs than outputs. To overcome this, we propose the idea of multirate sampled-data control-by carefully choosing faster input sampling rates, we obtain a lifted discrete-time system, which has the same number of inputs and outputs and does not give rise to the causality constraint. The adaptive control strategy is then applied to the lifted system, resulting in a multirate adaptive output feedback controller which is implementable digitally and provides closed-loop stability under certain conditions. The results reported here are validated on an experimental cart-crane system.

Brief paper: Output feedback strict passivity of discrete-time nonlinear systems and adaptive control system design with a PFC

In this paper, a passivity-based adaptive output feedback control for discrete-time nonlinear systems is considered. Output Feedback Strictly Passive (OFSP) conditions in order to design a stable adaptive output control system will be established. Further, a design scheme of a parallel feedforward compensator (PFC), which is introduced in order to realize an OFSP controlled system, will be provided and an adaptive output feedback control system design scheme with a PFC will be proposed.

Adaptive PID controller design based on output feedback passivity for discrete-time nonlinear systems

This paper deals with the design of an adaptive PID control system for discrete-time SISO non-linear systems. The proposed method is based on the output feedback strictly passive (OFSP) property of the controlled system. A fundamental design scheme of an adaptive PID control system with a parallel feedforward compensator (PFC) introduced in order to realize an OFSP augmented controlled system will be provided.

Output Feedback Strict Passivity of Discrete-time Nonlinear Systems and Adaptive Control System Design

Abstract In this paper, a necessary and sufficient condition for a discrete-time nonlinear system to be strictly passive is derived and OFSP (Output Feedback Strictly Passive) conditions will be established. Based on the obtained OFSP conditions, an adaptive output feedback controller design method which can solve causality problems will be proposed for a discrete-time nonlinear system.

Output feedback control of multirate sampled systems with an adaptive output estimator

This paper deals with a controller design problem for multirate sampled systems with a slow output sampling rate and a fast input updating rate. An adaptive output estimator based on a reduced first order system will be proposed in order to design an output feedback controller with a fast-rate input updating period.

Dual-rate Robust Adaptive Control of a Cart-crane System

In this paper, the application of the adaptive output feedback control based on ASPR conditions to a cart-crane system is considered. The multirate sampling and lifting technique and dual-rate control is adopted in order to apply the ASPR based adaptive control scheme. Further, for the obtained dual-rate discrete-time system, a robust adaptive output feedback control which can solve the causality problem is proposed and the boundedness of all the signals in the resulting closed loop control system is analyzed

Adaptive Output Feedback Control of General MIMO Systems Using Multirate Sampling

In adaptive output feedback control based on almost strictly positive real conditions, a technical difficulty arises when the multi-input multi-output (MIMO) system under consideration is non-square, and in particular, has less inputs than outputs. To overcome this, we propose an idea of multirate sampled-data control. That is, a lifted discrete-time system, which has the same number of inputs and outputs and does not give rise to the causality constraint, is made by carefully choosing faster input sampling rates. The output feedback based adaptive control strategy can then be applied to the lifted system under certain conditions. The results reported here are validated on numerical simulations through a cart-crane model.

Output feedback control of dual-rate sampled systems using an adaptive output estimator

This paper deals with a controller design problem for dual-rate sampled systems with a slow output sampling rate and a fast input updating rate. An adaptive output estimator based on a reduced first order model of the controlled system will be proposed in order to design an output feedback controller with a fast-rate input updating period.

Robust Adaptive Output Feedback Control of MIMO Systems Using Multirate Sampling

In adaptive output feedback control based on almost strictly positive real (ASPR) conditions, a technical difficulty arises when the controlled multi-input multi-output (MIMO) system is non-square. To overcome this, the idea of multirate sampled-data control has been proposed. That is, through careful choice of faster input sampling rates create a lifted discrete-time system which has the same number of inputs and outputs and does not give rise to the causality constraint. The output feedback based adaptive control strategy can then be applied to this lifted system under certain conditions. In this report, we propose a robust adaptive controller design scheme for non-square MIMO systems using the multirate sampling strategy without the causality problem