Hiroshi Ohsaki

A Consideration of nonlinear system modeling using the projection method

This paper considers modeling of nonlinear systems, especially nonholonomic systems, by the projection method proposed by W. Blajer. The projection method focuses on constraints of a system, and it can make a model of a non-holonomic system in the similar way of a holonomic system. The projection method also permits us the modeling as follows: first of all, the sub-model of each component is derived, and combining them gives the entire model. In this way, the complex and large system modeling can be decomposed into each easy-small sub-modeling.

Support control to promote skill of riding a unicycle

In this paper, we propose control system which supports unicycle operation for humans skill up. Therefore, the unicycle operation analysis method is proposed first, and it is shown usefulness by experiment. The element used for analysis are riders CP (Center of Pressure) and MBP (Moment Balancing Point) which negates a saddle rotation moment. Using those elements, we propose evaluation method of unicycle riders operation. Dynamic unicycle simulator is used for supports unicycle operation for humans skill up.

A consideration of human-unicycle model for unicycle operation analysis based on moment balancing point

The unicycle operation is a good exercise for training of the sense of balance, the agility and the ability to coordinate the body according to situations. This paper aims to give an interpretation of the relationship between the moment balancing point (MBP) and the center of pressure (CP) in a riding a unicycle from the human motion viewpoint. This paper shows derivations of Human-Unicycle model motion equations according to the Projection Method, and represents the relationship between the MBP and the CP of the the model by considering structure and constraint reaction forces of the model.

Rotational motion control design for cart-pendulum system with Lebesgue sampling

This study addresses a discretization method with Lebesgue sampling for a type of nonlinear system, and proposes a control method based on the discrete system model. A cart-pendulum system is used as this example. Applying this control method to some real system, how to implement the controller is a crucial problem. To overcome the problem, an impulsive Luenberger observer is introduced with a numerical forward mapping from the current system state to the one-step ahead state by well-known Runge-Kutta method. As the result, a cart-pendulum system with a quantizer, whose quantization interval is relatively large, can be controlled effectively. Numerical simulations are performed to verify the effectiveness of the proposed method.

Development of a control system for supporting to grow human skill of a unicycle

The riding operation of a unicycle attract attention, because it improves the balance sense and trains the coordinate ability to move the body dexterously according to a situation. This study regards a unicycle as the subject of research, and analyzes the process of achievement of the balance sense and the coordinate ability for riding the unicycle. Thus, we derive a motion equation of a system which considered a force and a torque to the system by the operator using the projection method. We develop a dynamic unicycle simulator, using the equation of motion, which prepare an environment for analysis, training, teaching, and assist of the unicycle operation.

Analysis of human's stabilization controller in a unicycle operation using Inverse Regulator Problem of optimal control

A purpose of this study is analyzing a humans controller to understand a mechanism of skill acquation processes for riding a unicycle. In order to analyze the controller, inputs which an operator gives to the unicycle and states of the unicycle are measured and a human-unicycle model as same as the experiment is derived. A weighting matrix to the state is obtained from the states, the inputs and the model solving Inverse Regulator Problem. The humans controller for riding the unicycle is discussed by the obtained weighting matrix.

Optimality recovery of feedback control system based on discrete-time state dependent riccati equation

In this paper, optimality recovery of a control method based on the discrete-time state-dependent Riccati equation (DSDRE) is discussed. The relationship between the DSDRE method and the Hamilton-Jacobi-Bellman equation (HJBE) concerned with optimal control for discrete-time nonlinear systems is addressed briefly. Based on the relationship, the stability of the DSDRE method is investigated with the Lyapunov theorem. As a result, the asymptotical stability holds for the DSDRE strategy is proven for some special case, and the optimality does not hold under infinite-horizon criteria in general. Hence an iterative numerical method is proposed to improve and recover the optimality along a state trajectory obtained by the DSDRE strategy. The method is verified through numerical simulations.

Human dexterity analysis in stabilizing operation of inverted pendulum

A final purpose of this study is to design a dexterity assistance system for operating a machine. In order to design a dexterity assistance system, analysis of human characteristics is necessary. And the study of stabilizing operation of an inverted pendulum is important for understanding the neural control of balance and skill acquisition. Therefore, this study focuses on stabilizing operation of an inverted pendulum, and analyzes the dexterity process of human operation. This paper assumes that the human operation is PD control. And feedback gains are identified at each danger in the operation, and relationship between the results of identification and skill level is discussed. Furthermore, we verify the proposed operation analysis technique by the variation of the order of the human controller.