This paper deals with the control of temperature of distillation column. This distillation column is very difficult to control because operational conditions are changed day by day. Dynamical models are built from operational data with ARMAX model. The generalized predictive control (GPC) method is very effective to control temperature in this system. The control derived this method is applied to estimate PID control equivalently. Control results are excellent and will be applicable for practical plant.

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Various adaptive controls were suggested up to now. However, the adaptive controls are not widely recognized as practical control method. Practical adaptive control is thought to be established successfully by being only provided two suitable elements, one of which is robust and adaptive estimation corresponding to a system signal aspect and the other is feedback control applied with less exceptinal treatment even for nonminimum phase and/or delay system. After an daptating period, the two elements adaptive control can guarantee good performance, but in the period, often raises extreme action. This paper deals with the suitable estimation and feedback control, and improvement of control action in the adapting period by setting a control target in a zone instead of a point.

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An approach to Nonlinear Model Predictive Control(NMPC) is presented on the basis of the process models described by nonlinear differential equations in time-domain. Since NMPC is formulated in discrete-time space, the continuous process models must be converted to discrete-time equivalents by some approximation such as Taylor series expansion. In this paper, the continuous process models are converted to discrete-time equivalents using orthogonal collocation in order to reduce the truncation error. Simulation study shows that the performance of proposed control system is applicable to start-up of batch chemical process which shows nonlinear behaviour.

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A new control technology for building HVAC system to save energy is presented in the paper. Recently many inverter driven mortars are introduced in buildings for energy saving. For HVAC systems, mortars are mainly used for air-conditioning fans and water pumps. Due to the flexibility of the inverter driven mortars, more energy saving operation has become feasible than ever. The control strategy we proposed consists two functions, that is, (1) optimum temperature calculation function and (2) model predictive controller for cooperative operations for fans and pumps.

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Automatic generation of process operation sequences is considered for batch process systems. Knowledge of process equipments and material processing procedures are represented by directed graphs respectively. Many series of operation sequence are obtained efficiently with these graphs by introducing subgraph isomorphism algorithm. Among the sequences, parallel operations in different equipments in the same time are realized. Operation procedures treating multiple products in parallel are also realized. Moreover, alternative operation sequences in abnormal situation can be generated on-line by dynamically applying this algorithm. Several examples of sequence generation are demonstrated and the performance of the algorithm is studied.

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In the chemical process industry, batch processes are becoming important increasingly. But there is a problem in the present control system regarding human management and maintenance. Therefore, this paper is proposed a framework of autonomous decentralized control system for chemical batch processes. In this framework, the control systems become easy to supervise and interrupt by human operators. The management of recipe and facility is becoming simple to maintain and modify. Through a case study, it has been shown that the proposed framework can provide a useful implementation of batch control system.

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In this paper, we propose a fault diagnosis method to detect and identify faults which occur in plants. In our approach, we first describe the behavior of a plant by Petri nets, then construct monitors to detect and identify faults using Petri net embeddings. The monitors detect faults by performing parity checks for reachable markings. We also discuss briefly how to detect faults where some places and/or some transitions are unobservable.

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Extracting essential variables, which drive a process, from measured variables and monitoring them will improve the process monitoring performance. In the present work, a new multivariate statistical process control (MSPC) method based on independent component analysis (ICA) is proposed for realizing this concept. In addition, to cope with changes in operating conditions such as load changes, SPC techniques are integrated with external analysis. The simulation results have clearly shown the superiority of the procesed ICA-based MSPC over univariate SPC and conventional MSPC using principal component analysis (PCA) and also the usefulness of external analyisis.

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This paper considers quadratic-in-the-state representations, which consist of state equations that are at most quadratic with respect to the states, as representations for a broad class of nonlinear systems. A necessary and sufficient condition is shown for existence of a quadratic-in-the-state representation that has the identical input-output relation with a given nonlinear, system. That condition is characterized by the algebraic structure of the observation space of the given system and is so mild that many types of nonlinear systems have a quadratic-in-the-state representation. The quadratic-in-the-state representation is expected to be useful as a general model structure in identification of unknown nonlinear systems.

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In this note it is shown how the n-dimensional rigid body equation naturally leads to a Hamilton’s canonical equation, and how this may be used for controller and observer designs, by using the geometry of mechanical systems on manifolds and avoiding the parameterization of Lie group SO(n). Based on this approach, it is possible to focus on the intrinsic property of the system.

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This paper proposes a new approach to the Input-to-State Stable(ISS) small-gain theorem. A new proof of the ISS small-gain theorem is obtained by constructing a Lyapunov function explicitly, which contrasts with existing proofs based on input-output analysis. The construction of Lyapunov functions through the use of state-dependent scaling motivates the author to formulate a new criterion for stability and performance of interconnected nonlinear systems. Furthermore, a nonlinearly-scaled version of the ISS small-gain condition is addressed.

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In this paper, a new approach to stability and performance of nonlinear interconnected systems is developed by smoothly generalizing a recently-introduced method of the state-dependent scaling. A set of popular Lyapunov stability criteria, the Input-to-State Stability(ISS) small-gain theorem and the scaled H^∞ small-gain condition (or structured singular value) are included as special cases. The criteria show us how to construct Lyapunov functions explicitly.

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In this paper, an angle tracking (position control) problem of a planer manipulator by digital feedback control is considered. It is well known that the angle tracking is accomplished by continuous-time PD feedback control, however, the stability is not guaranteed any more with digital implementation of the PD control law. In fact, unstable response is observed with larger PD gains. In this paper a stability condition for a manipulator with digital PD feedback control is derived. The usefullness of the derived condition is also demonstrated through experimental examples.

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For discrete-time constrained systems, a minimax control problem is discussed in terms of LP-based approach. By introducing a solution to linear minimax problems, the optimal control and worst-case disturbance are characterized in the finite time horizon setting. Offline calculation method of receding horizon control law is also obtained via parametric linear minimax game.

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This paper deals with analysis of the worst-case bumpy response due to disturbances for systems with switching and uncertainty. Bumpy responses are often caused by switching in control systems. Since those responses are harmful, several methods of bumpless transfer have been proposed. However, most of the existing results do not deal with robustness. Recently, a method has been proposed to analyze the worst-case gain from past disturbance to future output based on LMIs. Although that result guarantees robustness, it may not be suitable for further applications to e.g. synthesis problems since the result lacks duality. This paper proposes a method to analyze the worst-case L₂ gain from past disturbances to future controlled output based on linear matrix inequalities. The condition given in this paper has symmetry in terms of duality. Moreover, a numerical example shows that the proposed method gives a less conservative result than existing methods.

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This paper discusses the finite-time optimal control problem of a class of piecewise affine (PWA) systems, where the switching action of the discrete state is determined at each sampling time according to a condition on the continuous state. An issue in the control design of the continuous-time PWA system is pointed out to motivate the use of such PWA systems, and then an optimal continuous-time controller is proposed.

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This paper addresses an interesting switching strategy of gain-scheduled controllers for linear parameter-varying systems. Dividing a whole of an operating range into some small subranges which are covered with a set of convex hulls, we design gain-scheduled controllers via linear matrix inequalities for each subrange while using a common Lyapunov function for each but non-common for others. We then switch from one gain-scheduled controller to another in an intersection of two neighbor convex hulls online. Although switching action generally generates non-smooth control input which may cause undesired behavior and even instability, our proposed method guarantees perfect smooth switching to avoid such behavior. A design example of aircraft longitudinal motion control is included.

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In this paper, we discuss trajectory tracking control of a wafer transfer robot. In order to establish an accurate model that is required in high performance control of the robot, we derive weighting functions from the models obtained by system identification at several attitudes. The weighting functions will be interpolated between the robot’s operating range. We design a controller for such model by gain scheduling techniques. Finally, we demonstrate numerical simulation of tracking control.

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In this paper we propose a control system design method in consideration of actuator saturation. By applying hyperbolic tangential function to the saturation description, we introduce both the time differentiation of contol input and the anti-windup control structure with feedback of the error between the input and the output of the saturation function. Furthermore, we formulate the linear parameter-varying system to design the gain-scheduled controller. The effectiveness of our proposed method is verified by carrying out experiments of positioning control for a cart and inverted pendulum system.

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This paper proposes the gain-scheduled inverse system and its design method. The inverse property of this system is characterized with a weight function and the induced L₂ norm. As for design methods, the usual dynamic gain-scheduled controller has derivatives of parameters or the existence condition is formulated with BMIs owing to a parameter-dependent Lyapunov function. But with the proposed method, the gain-scheduled inverse system does not have derivatives of parameters and the existence condition is formulated with LMIs despite using a parameter-dependent Lyapunov function. So the proposed design method makes a realistic gain-scheduled inverse system with ease.

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The backstepping method is applied to a tank system to control the flow and temperature at the exit. A robust backstepping control law is developed for the plant with uncertainties. The validity of the proposed method is demonstrated through simu1ations.

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In this report, we consider the application of a robust adaptive backstepping method based on the high-gain feedback strategy to a continuous stirred tank reactor (CSTR) model. The designed robust adaptive control system shows a good performance in spite of the CSTR model has highly nonlinearities and uncertainties at control input terms.

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In this study, a nonlinear control design based on backstepping approach is proposed for an energy storage flywheel rotor-zero power AMB system. A vertically constructed flywheel rotor magnetic bearing system is modeled with nonlinearity. The rotor is assumed to be rigid and the cylindrical and conical modes of the rotor are considered. The equation of the rotor-AMB system is transform to have a collocated system between control input and displacement of the rotor. One of the improvements obtained in this study is the low loss of the AMB system due to decreased control currents. Simulation and experimental results showed good improvements for practical implementations.

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This paper considers the position tracking problem of a magnetic levitation system in the presence of modelling errors due to uncertainties of physical parameters. A robust nonlinear controller is designed to achieve excellent position tracking performance. The recently developed dynamic surface control is modified and applied to the system under study, to overcome the problem of “explosion of terms” associated with the backstepping design procedure. Input-to-state stable property of the control system is analyzed, and experiment results are included to show the excellent position tracking performance of the designed control system.

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Crane lifters are widely used in industrial plants and rehabilitation equipment. To improve the efficiency of cargo handling with cranes, it is necessary to control the crane trolley position so that the swing of the handling load is minimized. Crane lifters have the dynamics with nonlinearities and time varying parameters. The backstepping method is powerful technique to design a nonlienar daptive controller. In this paper, a nonlinear controller for the anti-sway control of crane lifters is designed via backstepping method.

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In this paper, the asymptotic tracking control problem of a rigid spacecraft is considered. Three type control laws are presented by using backstepping technique in the framework of the globally nonsingular unit quaternion representation of a spacecraft. The first one is a PD-type control law which doesn’t require much information about the spacecraft model. The second is model-dependent, that is, the inertia matrix of the spacecraft needs to be exactly known. And the last one is derived by adaptive control assuming that the inertia matrix is unknown. Furthermore, an application of rendezvous docking to an uncooperative target is presented.

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We address nonlinear attitude control problem of flexible spacecraft. For this issue, we must consider elastic vibration of flexible structure. In this paper, we treat the affect of elastic vibration as uniformly bounded disturbance and derive stabilizing controller of flexible spacecraft by using backstepping method and concept of nonlinear damping. By the approach, boundedness and asymptotic stability of attitude angle and angular velocity of this system are shown to be guaranteed. Effectiveness of proposed method is verified by simulations.

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The backstepping method is an effective approach for non-linear models, which can be easily extended to an adaptive control. However, since it has been mainly developed from the theoretical point of view, it requires more examples of the application to real systems. This paper considers about a design method for attitude control of a helicopter model whose model is described based on non-linear models.

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Advanced safety vehicle (ASV) assists drivers’ manipulation to avoid tra±c accidents. A variety of researches on automatic driving systems are necessary as an element of ASV. Among them, we focus on visual feedback approach in which the automatic driving system is realized by recognizing road trajectory using image information. The purpose of this paper is to examine the validity of this approach by experiments using a radio-controlled car. First, a practical image processing algorithm to recognize white lines on the road is proposed. Second, a model of the radio-controlled car is built by system identi¯on;cation experiments. Third, an automatic steering control system is designed based on H₁ control theory. Finally, the e®ectiveness of the designed control system is examined via traveling experiments.

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This paper is concerned with a new direct adaptive algorithm which is applicable when the secondary path dynamics are uncertain. In order to reduce the actual canceling error, the two artificial errors are introduced and are forced into zero by adjusting three adaptive FIR filters in an on-line manner. The distinctive feature of the methed is that the adjusted parameters do not have to converge to the true FIR parameters but some constants, then the reduction of the two errors can attain the canceling at the objective point. The effectiveness of the proposed algorithm is validated in experiments using an air duct.

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This paper presents a robust stabilization of large space structures with rigid interconnections. It is shown that direct velocity and displacement feedback or simple dynamic displacement feedback can robustly stabilize the structures against any purturbations in mass, damping, and stiffness. Furthermore, the stability of the overall system is preserved even if the controller of a subsystem fails. These facts mean that these control laws have the same ability about robust stability and fault tolerance.

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A suspension system is proposed whose compliance for direct disturbance forces is zero. The zero-compliance property is realized by connecting a conventional spring and an active suspension mechanism with a linear actuator in series. The active suspension is designed to have negative stiffness for disturbance forces acting on the suspended mass. The fundamental properties of the proposed system are studied both theoretically and experimentally.

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In this paper a new lane detection method is proposed for highway lane departure warning. Its cost is reduced by using an existing back monitor camera and an embeded CPU on the market. The extended Hough transform and a bird’s-eye view image are effectively applied to perform high-speed lane detection. The method was built on an embeded CPU (Hitachi SH2E) as software. Then the extended Hough transform was executed at less than 66 milliseconds.

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The Toyota Intelligent Multi-mode Transit System(IMTS) is realized through combining the ITS technology for fully-automated cars with existing rail-way technology as an innovative transit system. At the Awaji Farm Park we have developed the IMTS specifically designed for the transport of visitors between two major areas. This is the first introduction of the IMTS as a practical transport. The system is composed of fully automated buses and a road-side system. The significant features of the bus controls are automated steering and pratooning. In this paper, the system configuration, bus control and operating system are described.

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In this paper, active steering systems and automated steering systems are provided based on model reference D^* control of a single-truck model which can treat the tire nonlinear characteristic between the tire slip angle and the tire lateral force. The automobile has two wheel steering (2WS) which is equipped with steer-by-wire technology. In manual driving, the driving safety increases by active steering and the driving easiness is attained by model reference D^* control.

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The slip of the automobile often arises in acceleration and in braking. As the result, the travel performance remarkably causes the adverse effect, since the grip force of the tire is lost. The driving force of automobiles is transmitted by a frictional force between tires and road surface. The frictional force is a function of the friction coefficient between tires and road surface and the weight of car-body. Due to a variation of this friction coefficient, the controlled object has an uncertainty. Hence, the drive-control of the automobiles with uncertain parameters is a very difficult problem. In this paper, we report the drive control system of automobiles by using sliding mode control theory which is a superior control method for uncertainty.

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A control-oriented uncertainty modeling on frequency domain is presented for a class of spectral systems with unknown high-order modal parameters. At any user-specified frequency, the set of all the frequency responses of the feasible systems is characterized on the complex plane in terms of the convex hull of several circle segments, where the system is said to be feasible if partial modal parameters are given and some other conditions are satisfied by the unknown parameters. We emphasize that such a characterization enables us to quantify the least upper bounds of errors for any specified nominal models, and to develop further efficient results using some additional information. It is shown that, if the dc gain information of the system is available, it reduces the size of the feasible set at all frequencies, and a finite-dimensional nominal model gives explicit tight error bounds. The efficiency of the presented scheme is demonstrated by a simple example of ideal flexible beam.

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In this paper, we analyze robustness of adaptive gradient algorithms against continuous-time disturbance signals. It is shown that a kind of H^∞ property holds for the adaptive gradient algorithms in the case where continuous-time outputs can be observed while it might not hold in the case where only sampled outputs can be observed. We also show an implementable method using the output over-sampling technique which gives better performance than the conventional and standard adaptive gradient algorithms. A numerical example is given to illustrate the effectiveness of the proposed method.

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Bias-compensated least-squares method is a consistent estimation method for parameters of pulse transfer functions in the presence of input and output noise. The method is based on compensation of asymptotic bias on the least-squares estimates by making use of noise variances estimates. In this paper, a new type of noise variances estimation method is proposed to overcome drawbacks of previously proposed methods. The main feature of the proposed method is to introduce a generalized least-squares type estimator in order to estimate noise variances. Results of computer simulations are presented to verify the performance of the method.

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Parametric estimation of the monocomponent noisy signals is considered in this paper. The Wigner distribution-based maximum likelihood (ML) estimator is used as estimation tool. Various types of the FM signals and noisy environments are considered.

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In this paper, an extremely simple control approach is proposed for the multichain systems. This method is based on a switching of two sets of control laws. Each law is given by a product of the generator and a time-invariant linear function of the state. The switching is based on the sign change of the generator. Global exponential convergence of all states is guaranteed. More importantly, the convergence rate is given explicitly. A remarkable feature of the proposed approach is that in each phase of the switching control, the ratio of state convergency is an exponential function of the displacement of the state driven by the generator. For the design of each control law, two methods are proposed.

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In this paper, we discuss grasping and manipulation of an object by two-fingered robot hand, each of which has six degree of freedom. The contact motion between the object and each fingertips is assumed to be the pure rolling. First, we provide a general formulation of a linearizing compensator for the motion of the object, the grasping force and some of the contact points. Second, we propose a control method which regulates of all contact points by utilizing a closed path of the controlled contact points. Numerical examples are shown to prove the efficiency.

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This paper describes position control of an RC hovercraft. The hovercraft has two fixed thrusters, and the thrusters generate thrusts of only three discrete values, that is, forward, backward and zero. Nonlinear receding horizon control is applied to position control of the hovercraft with the discrete inputs approximated by constrained continuous inputs. Although the nonlinear receding horizon control requires real-time constrained optimization, a fast algorithm is successfully implemented for the hardware experiment. This paper compares experimental results and simulation results of two dimensional motion.

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Time-State Control Form was proposed as one of the control method for nonholonomic systems. But this method needs input switching, so there is a demerit that the switching conditions may spoil the stability of the system. From the above backgrounds, this research considers the property of the control method based on Time-State Control Form from the viewpoint of hybrid systems. The control objects are limited to chained systems, and the conditions to stabilize the systems asymptotically are shown by introducing the Lyapunov functions which are invariant to input switching.

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This paper addresses the well-posedness problem of control systems composed of a bimodal piecewise-linear plant and a dynamic controller. First, we give a characterization of the controlled plant that is rendered well-posed via dynamic state feedback. Second, based on this characterization, we discuss an explicit structure of dynamic controllers that make the closed loop system well-posed.

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This paper proposes a model predictive control system for a max-plus linear system with a linear parameter-varying structure. Although the design method of model predictive control for the max-plus linear system has already been proposed, the conventional method has just dealt with the constant parameter case. Hence, the proposed method can deal with the wider class in max-plus linear systems than the conventional method.

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This paper deals with a class of hybrid systems whose dynamics changes discontinuously according to modes, which are determined by the state location. The dynamics of each mode is governed by continuous differential equations. First, we derive a condition of the mode transition which is robust against the initial error. Second, a procedure to apply the condition for the optimal control is shown. Furthermore, we reduce them to forms which are suitable for numerical methods.

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This paper is concerned with the initial conditions of an interconnected system that is composed of two linear implicit systems. For a single implicit system, an initial condition is called admissible if the system has a solution trajectory satisfying this condition. In the interconnected system, the set of admissible initial conditions of each sub-system may be reduced to a smaller subset due to the constraint imposed by the interconnection. We say that the admissible initial condition sets of the sub-systems are invariant under interconnection if they are not made smaller by interconnection. It is shown in this paper that the feedback and regular feedback structures of the interconnected system guarantee the invariance of the admissible initial condition sets under interconnection in the senses of impulsive-smooth distributions and usual smooth functions, respectively.

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In this paper, we consider a dynamic model of TCP/AQM(Transfer Control Protocol/Active Queue Management) networks and derive the dynamic model using linear systems with self-scheduling parameters. Here we focus on the constraints on the maximum queue length and tcp window-size, which are the network resources in TCP/AQM networks, and design a state feedback controller considering the constraints.

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In recent years, the Internet spreads widely, and Broadband communication services, such as ADSL and B Flet’s, become common to end users. As a result, packet loss and the fall of throughput, caused by the increase of router loads, come into question. To solve these problems, we focus on current TCP congestion control, which does not address the state of network congestion adequately, and suggest two new congestion control technique-rewriting header information of TCP packet by router, considering the state of network, and then evaluate its performance by simulation. The result demonstrate the effectiveness of proposing technique.

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