In this paper, we propose a method of control system design which takes actuator saturation into consideration. By using a hyperbolic tangential function in the saturation description, we introduce both the time derivative of controller output and the anti-windup control structure with a feedback loop of the error between the control output and the saturated input. Furthermore, we formulate a 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 study proposes a nonlinear adaptive control design using backstepping approach for output feedback type nonlinear control systems with unknown constant parameters. A class of nonlinear systems with parameter uncertainties and with some unmeasured states is of interest for nonlinear adaptive control. The proposed control design uses the control Lyapunov functions to maintain the stability of the control system and makes the parameter adaptation using tuning functions. One of the aim of this study is to prove the applicability of the proposed adaptive control design approach to the real control systems. For this aim, an active magnetic bearing system is used for experimental verification. The obtained results are encouraging for future studies.

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In this paper, we propose a method to apply a Two-Degree-of-Freedom (2DOF) control as such attempt of controlling a Multi-Axis Electro-dynamic shaking system has no requirement for iteration control and has real-time performance. We first introduce an ideal mathematical model and uncertainty weighting function for the system, and a feedback controller is designed using μ-synthesis. And we constitute 2DOF controller for a purpose to improve transient response. Then, an adaptive filter is added when control performance still can't be satisfied. Lastly, we show the performance of the controller by experiment using a resonant specimen.

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An existing adaptive version of the above result for the class of stable lumped systems with output delay, can achieve asymptotically tracking, but can not robustly achieve satisfactory transients for any system of this class. In this paper we derive an adaptive version with self-learning iteration of the above result for the class of stable lumped systems with output delay, so that asymptotically tracking and satisfactory transients are achieved for any system of this class.

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This study aims at establishing a robust intelligent control method with higher control performance and wider application region by developing the Cubic Neural Network (CNN) intelligent control method. In this study, the dynamical energy principle is embedded into the integrator of CNN that consists of multilevel parallel processing on different degree of abstraction. As a result of simulation and experiment, it was demonstrated that the integrated CNN controllers can stand up the double pendulum taking into account the cart position limit for the case of arbitrary initial condition of pendulum angle.

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This paper examines the potential enhancements to the liquid damping of a uni-directional Liquid Column Vibration Absorber (LCVA) through the inclusion of orifice plates. In previous work it has been found that use of an LCVA in its original configuration generally has damping that is less than optimum. Use of the LCVA could therefore result in a structure that may have a lower than optimal damping, and as a consequence may experience re-excitation. The work examined in this paper shows the damping enhancements that are possible by using orifice plates. The effect of orifice location and size is considered. The work conducted is both numerical [3] and experimental. As such the numerical work is also validated by experimentation.

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A new self-organizing fuzzy controller design algorithm suitable for multi-objective control problem is proposed based on the orthogonal array. The proposed algorithm uses a 3-level or the combined orthogonal array that has 3-level columns to adopt nonlinear search algorithm. The search algorithm is based on a region approach incorporated with the orthogonal array, not requiring any derivatives. The essence of the proposed algorithm is to introduce a multi-objective decision table (MODT) that contains the contribution ratio defined from its F-value, optimum level, sub-decision and decision for each rule. Rules of thumb are also proposed to enhance the rule decision process, although part of the guidelines still requires experts' judgment. It is shown that the proposed algorithm can be successfully applied to the fuzzy controller design of a rigid rotor-active magnetic bearing system with the strong non-linearity in dynamics and model uncertainty.

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A tracked vehicle is a kind of moving material, which moves with itself. Recently, it is required to move silently and with high velocity. With these requirements, the resonance problems have not been ignorant. In this study, the vibration characteristics of the crawler are investigated in order to recognize the actual vibration problems. At the controlling phase, we propose a bang-band feedback (FB) control method, which has the same control frequency as the vibration frequency. As a result, it is confirmed that both the bang-bang FB controls are effective and they have the sufficient control stability.

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We consider the attitude tracking problem of the axisymmetric underactuated spacecraft. It is known that the asymptotic stabilization of the system to any state is possible, and that the system admits flat output. Thus, the asymptotic model matching problem to itself is solvable. However, its flat output given in [6] include a singularity so that the control input which generates the state trajectory may not be unbounded. Tsiotras et al proposed a third order polynominal-type parametarization of the output trajectory which avoids the singularity. In this paper, the authors give a condition such that the given analytic output trajectory can avoid the singularity. Based on the result, we can use the broader class of output trajectories.

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A discrete output sliding control is studied for the discrete-time systems in this paper. This method carries insensitivity of the plant parameter variations and external disturbances. The switching surface design utilizes only the output and its delayed signals. And the closed-loop poles can be effectively assigned. A transformation method is given to convert the control system into a form of system with time-delayed inputs if necessary in certain cases. This method is applied to the position contact control of a high-speed rail system. Computer simulation is carried out to show the effectiveness of the proposed method.

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The aim of this paper is to design a sliding mode controller to regulate the speed and the flux of an induction motor to follow some desired references using a new sliding surface. The controller deals with the strong nonlinearities of induction motors. The design uses measurements of stator currents and the speed of the motor. Since the flux can not be measured directly, a mathematical model is used to calculate the values of the flux. In this work, the controller is tested and the results show that both the speed and the flux follow their references with fast response.

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This paper proposes a new control technique for compressor of Automotive Air-Conditioning System (AACS). It is based on Reference Model Following Based Sliding Mode Controller (RMFSMC) with disturbance observer. Variable Capacity Control (VCC) is widely attracted from saving energy and keeping the car comfortable. But it is difficult to realize it, since it has complex and nonlinear characteristics. To fix the problem, the mathematical model is derived from System Identification (System ID) and the RMFSMC has been designed. This paper introduces the developing process, simulations, and its experimental results.

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We developed a design method that can suppress the vibration from high-order resonant modes in a head-positioning system of a hard disk drive. We used the vector locus of an open-loop transfer function to design both the controller and the structure simultaneously. Application of the method to an actual hard disk drive showed that positioning accuracy under high-order resonant modes can be improved by 55%. In addition, when all resonances are in-phase, the developed method can suppress vibrations caused by all mechanical resonances. We concluded that the method can design a control system with high robustness and good following control performance.

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Shock-response-spectrum (SRS) analysis of a seeking current in a hard disk drive was used to predict acoustic noise frequencies. This analysis method can be used for optimizing the seeking current so that seeking noise is reduced. It was verified experimentally that the prediction accuracy is from -25% to +12% and seeking noise was reduced by about 4 dBA on average by optimizing the seeking current.

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A new method to measure the disturbance of the optical disc, the closed output disturbance estimator (CLOE), is proposed and its validity is evaluated. In this method, the optical pick-up model and the nominal sensor gain are acquired by experimental method and loop gain adjustment (LGA). Proposed algorithm is constructed on the MATLAB SIMULINK and downloaded to the DSP board. Test DVD disc is used to qualify and quantify the disturbance of ODD under various conditions. The disturbance characteristic of ODD is analyzed and the servo loop based on this result is designed.

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This paper presents the design of a Linear Quadratic Regulator (LQR) for a Toroidal Continuously Variable Transmission (TCVT) system for cars. This system is unstable in reverse mode and is nonlinear according to the car speed. A gain-scheduling technique is then associated to the LQR method. Several experiments with test-bed and with actual vehicle shows the effectiveness and the robustness against car speed and torque shift disturbance of the controller.

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For a traveling crane, various control methods such as fuzzy control and optimum control are studied. In the control of an actual traveling crane, it is important to accurately stop the crane at the desired position by positioning control and anti-sway control. In this pare, we used the H_∞ control theory which performs well even when there are modeling errors and parameter variations. The results of several experiments confirmed that the H_∞ control system is effective.

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Input shaping control for a planar gantry crane with load hoisting is investigated. The swinging motion after a move limits the performance of the system to do subsequent job. To reduce the residual vibration (swinging motion), a modified input shaping technique is used. The technique is easy to implement and does not require feedback of adaptive controller since it is a kind of feedforward method. The modified input shaping method offers more significant reduction in the swing angle of the gantry system, compared to those of the conventional and robust conventional methods.

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Rotary crane control based on several discretizing methods has been proposed in this paper. The motion of the crane load is described by a discrete time system by assuming zero order and trapezoidal hold for the boom rotation. The stabilization of the load boils down to a finite settling time problem with constraints. This problem is reduced to solving a 6-th order equation for five step case, and an optimizing problem with constraints for more step case. Various experiment results have been given to show the effectiveness of the proposed method.

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In this paper, attitude control of a spacecraft which consists of two rigid bodies coupled by a ball joint is discussed. First, we propose a time-invariant discontinuous feedback controller for a class of nonholonomic systems, first order systems, based on Lyapunov control. The first order system is a system where the input vector fields and the first level of Lie brackets between them span the tangent space at each configuration. Next, the controller is applied to the spacecraft when the angular momentum of the system is zero, and the effectiveness of the controller is verified by numerical simulations.

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In this paper, a dynamic impact control is proposed. To deal with impact phenomenon and to establish the control method, a pendulum-like juggling test system is developed. On this system, a slider hits a ball suspended by a wire and the energy is controlled via impact force from the slider. For stable juggling motion, it is necessary to make the slider reach to target position keeping specified velocity just on specified time. The reference trajectory for the slider control is generated and adjusted in real time, and the proposed variable structure (VS) servo control enables chattering-free precise tracking to the reference trajectory. Combining an estimator based on an exact VS-differentiator enhances the ability of the VS-servo control. The effectiveness of the whole juggling strategy is verified by simulation and experiment.

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Toroidal continuously variable transmissions (TCVTs) are being used for automobile power-train systems for the purpose of reducing energy consumption. In order to compensate for the non-linearity and time-variant properties of a TCVT, a gain scheduled non-linear servo controller has been designed. Its effectiveness has been verified through computer simulation results and experimental results obtained with an actual TCVT.

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This paper deals with a control technique of eliminating the transient vibration of a geared mechanical system with backlash. This technique is based on a model-based control. The control model estimates a load speed. The difference between the estimated load speed and the motor speed is calculated dynamically and is added to the velocity command to suppress the transient vibration of the load. This control model is easily obtained from design or experimental data and can be easily integrated into a DSP. This control technique is applied to a mechanical system composed of spur gears. Simulations and experiments show satisfactory control results.

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For the improvement of lifesaving rate and reduction of sequelae on serious illness patients who are transported by ambulance, we propose a new mobile communication system, i.e. motion pictures transmission from mobile ambulance via satellite to the emergency medical center for the adequate diagnosis by the medical doctors. For this purpose, satellite antenna tracking system onboard the experimental car has been developed. This paper describes the overall system of the mobile ambulance data transmission via highly inclined satellite for the avoidance of shadowing and then some details of the antenna tracking system.

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The purpose of this study is to realize horse-like walking by a quadruped robot. First, in order to understand the gait of horse, we analyzed the gait of a trotting horse in a sagittal plane. We also studied the structure and function of skeleton, equine muscles, and tendons. As a result, in this paper we proposed the model of horse-type quadruped robot. Its characteristics are those : Next the quadruped walking robot PONY was desighed and made. We analyzed the walking horse's video data, and proposed the horse-like gait. Next, we did the simulation experiment to examine the gait. The experiment of the transitional locomotion from walk to trot.

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Recently, land-mine clearance activities have been addressed in the world. We proposed the mine detecting method using six-legged robot. Concerning the mine detecting work by legged robot on the mine field where is uneven terrain, the legged robot is demanded the stable mine detecting work. In this research, we propose a new attitude control method for a six-legged robot using optimal control theory. The proposed attitude control method is examined by 3-D simulations and the experiments of mine detecting six-legged robot.

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Power grasp can hold an object much safer than precision grasp, e.g. pinching grasp, can do against disturbance forces applied to the grasped object. Nevertheless, it easily becomes unstable for impulsive disturbance forces and may drop or even crush the grasped object if the hand does not have suitable compliance. Now, it is known that a tendon-driven robotic mechanism can adjust the joint mechanical elasticity by controlling the extension (pulling) force of tendons. In this paper we investigate elasticity adjustable area with respect to the power grasped object with a tendon-driven robotic hand. After intorducing basic results about tendon-driven robotic machanisms, We formulate the elastic matrix with respect to an object grasped with a tendon-driven robotic hand. After this, we present the elasticity adjustable area numerically for a planar two finger robotic hand and show some experimental results.

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This paper presents a novel variable impedance control method for a human-robot cooperative task. There is a possibility that an impedance control system based on a positioning control of a robot with time delay of the robot and a human operator becomes unstable, when stiffness of a human arm is increased in the human-robot cooperative task. A proposed variable impedance controller varies a viscosity coefficient of the robot in proportion to an estimated value of the stiffness of the tip of the human arm. A proposed variable impedance control makes the human-robot cooperative system stable and the cooperative task easy.

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This paper is concerned with the analysis of a hopping robot with an impulsive actuator. A simple hopping robot model with two masses and a spring is analyzed to investigate the timing of jump action and strategy to maintain the jump height. We have proposed a mechanism to generate impulsive forces using a motor.

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Since timing belt drives have the advantages of low costs and accurate transfer characteristics, they are widely used in industrial machines and office automation equipment. However, timing belt drives have problems with periodic transfer variations caused by eccentric pulleys, interlocking belt and pulley teeth etc. Though it can be said that high feedback servo gain is effective in suppressing the periodic variations, the high gain easily makes the system unstable because of the elasticity of the drive system and the modeling errors. In this paper, we propose a control technique that suppresses periodic variations using a disturbance observer. First, we analyzed the mechanism of the generating variations caused by eccentric pulleys that are the most influential of all. Considering the periodic variations, we suggested the sinusoidal model for disturbances. The by implementing I-P speed control with disturbance compensation using the estimated disturbances from the observer, we verified the effectiveness of the disturbance compensation method.

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The purpose of this paper is to investigate behaviors of elastic joint robots driven by various types of controllers against external disturbances applied to them. The elasticity is introduced intentionally by installing elastic devises in their transmission. We consider about four types of controllers. commonly used to control elastic joint robots. We investigate the role of the compliance introduced by the mechanism and the controllers and show numerical simulations.

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In this paper, a vibration control system design for a flexible arm that possesses bending and torsional modes is investigated. First, an experimental flexible arm is made with an auxiliary mass connected to the other end via an extension bar so that the center of the stiffness of the arm may not exist in the direction of motion of the auxiliary mass. The auxiliary mass denotes payload. A three-degrees-of-freedom (3DOF) reduced order model is identified according to Seto's procedure. Based on the model obtained, a robust control design procedure utilizing H-infinity control theory is applied. Control experiments are carried out to verify the effectiveness of the presented design procedure.

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In this paper a new type of sliding mode controller with gain-scheduled variable hyper plane for position and force control is presented. In this controller the hyper plane in sliding mode controller is continuously adjusted according to the environmental stiffness identified in real time. This controller is applied to force control using a one-degree-of-freedom manipulator system. and the performance of this controller is verified on both simulation and experiments.

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Most robots are driven through reduction gear units. Because of the flexibility of the drive system, the vibratory behavior is caused. The drive system of the robot joint can be modeled as a two-inertia system. In this paper, we consider the two-inertia system with the torque, motor-acceleration and load-acceleration feedbacks. First, it is explained that the inertia-ratio is a very important factor. Second, it is shown that these feedbacks can change the inertia-ratio. Next, the performances of I-P speed control systems with feedbacks are compared. Finally, the experiments are performed. As a result, the torsion vibrations are suppressed effectively.

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The purpose of this study is to control simultaneously the motion and vibration of a very flexible flat-plate structure. For this purpose, we propose an extended physical modeling technique^<[2]> which is able to expand to multi-body dynamics in flexible structures. The 2DOF optimum integral control theory is applied to the control of motion and vibrations of a structure. The results of the simulation are compared to the results of experimentation. It is verified that this control method is effective for high-speed motion and provides good vibration control of the plate structure.

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The present paper proposes two kind of mine detection robots which mean the six-legged walking robot with two manipulators based on the added stability, mobility, and functionality. One robot is COMET-II which is driven by electric power and not so big robot. The another robot is a full autonomous robot COMET-III which is driven by hydraulic power. COMET-III has a crawler and six legs and its weight is 900Kg. The improved this kind of robot will be engaged for mine detection job in Afghanistan soon.

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This paper proposes a mine clearance hand for the existing mine detection robot COMET III and its successor COMET IV. The task of the robot hand installed on the robot is to neutralize/disarm or/and remove armed mines on an actual mine field. The different difficult environments of mine fields, mine types and mine clearance methods are described. The structure of the proposed hand and its control strategy is introduced.

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In this paper, we investigate the path following control strategy for a mobile robot with unknown obstacles detected on the planned path. For a known space with known obstacles, the path planning methods can generate the shortest collision-free path from the start to the end. The unknown obstacles may appear on the planned path and the mobile may not follow the original path. The obstacle avoidance mode is added into the controller in the research. Fuzzy controllers with the five distance sensors on the mobile can guide the mobile successfully. The computer simulations are given to verify the proposed algorithm. We find that locations and directions of the distance sensors will affect the results.

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In this paper, we propose the on-line adaptive trajectory planning by evaluating acceleration of designed trajectory. The tracking speed should be changed with curvature of the given trajectory. In order to change its speed, the time parameter is scaled by designed trajectory acceleration. We verify that the control performance is maintained oven if a drastic change of reference is given by means of changing time parameter.

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For linear nonholonomic constraint systems, we prove that Jourdain's principle is not derived from D'Alembert's principle but equivalent to it if the variation is defined in the phase space rather than the configuration space. For nonlinear nonholonomic constraint systems, that the virtual displacements are undefined causes the inability of D'Alembert's principle to treat them; Jourdain's principle can be proved to be applicable through the application of Gauss's principle. The Newton-Euler equations of motion for rigid bodies in the form of Jourdain variational principle is first derived. The merit of Jourdain's principle relative to Gauss's principle is that the former does not need to evaluate the acceleration in the derivation of the equations of motion as does the latter.

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The present paper proposes a sliding-mode control method that incorporates a strategy to avoid singularities which occur during target capture. The position and attitude of the end-effector of the manipulator are guided using the traditional sliding-mode control method based on the generalized Jacobian. In the proposed control algorithm, when the manipulator approaches a singularity, the attitude/position of the main body of the space robot is controlled such that the manipulability becomes greater. In order to effectively avoid the singularity, the direction in which to move the main body is selected and the acceleration direction of the end-effector is modified taking into account the acceleration of the main body. The effectiveness of the proposed method is verified through numerical simulations.

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A methodology is developed to simulate flexible multibody systems subject to the action of a digital control system. The mechanical model is built in the formalism of flexible multibody dynamics using the Finite Element Method. At the begining of each sampling period, the model of the control system is used to compute the control forces and torques applied to the mechanism. A second-order system with a direct velocity feedback controller is considered to study the performances of the method. A modification of the classical Newmark algorithm yields outstanding improvements in the results quality.

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In this paper we discuss about dynamic response of a tethered system under attitude control of end body. The system in consideration is composed of a string and rigid bodies attached at its end. We formulate the motion of the string taking into its flexibility. We attempt to control the attitude of the end body. The control technique is consists of attitude control by the reaction wheel, attitude control by the joint torque, and attitude control by the reaction wheel with the joint torque control to cancel accumulation of angular momentum of reaction wheel. First eigenvalue analyses were carried out for these cases where control gain changes. Second the motions of the controlled system are discussed under the free vibration and forced vibration.

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Impact processes can be implemented in the multi-body system approach using the coefficient of restitution which represents the energy loss during impact. Replacing costly experiments the coefficient of restitution may be determined by numerical computations on a fast time scale using finite elements. Experimental validation proves the accuracy of the impact simulations on multiple time scales for impacts on an aluminum rod and a brass rod as well as a half-circular plate.

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Due to the high nonlinearity of large displacement motions inverse dynamics is a standard control concept well established in robotics and walking machines. It is shown that inverse dynamics results in high energy consumption and requires large power supply. For autonomous robots and walking machines the power supply adds to the weight, and additional weight needs more power again. It is proposed to use local energy storage by springs to overcome the drawback of inverse dynamics. The design principles for reduced energy consumption are outlined with simple mechanical models and will include nonlinear characteristics of the springs to improve further the local energy storage capacity. An application to a robot arm modeled as multibody system is shown.

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A ladder of the ladder truck with the lift mechanism often generates a vibration at the time of the lift operation. This paper describes the simulation analysis of the dynamic behavior of extension motion and elevation motion which are one of the lift mechanism in order to make clear its vibration phenomena. We make the dynamic analytical model composed of 2 sections ladder using Multibody Dynamics. An equation of motion is derived using differential algebraic equation (DAE). We investigate the validity of our proposed simulation analytical method by comparing the simulation results with the experimental ones.

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A simplified dynamic model of a passenger car automatic transmission is developed for simulating transient vibration in gearshifts. A finite element method is proposed for presenting the transient dynamics of the parametric system. The element matrices are developed using variable speed rations and the global stiffness and damping matrices are then formulated corresponding to the defined global coordinate vectors. Free vibration analysis and the transient 2-3 upshift simulation are discussed and the results are presented.

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It is available to grasp the angular displacement of a human body for instruction on a sport performance. Provided the instantaneous angular velocity is known, the angular displacement may be obtained by the integration of it. However, although the angular velocity and the rotational axis of a rigid body can be easily derived, how should the angular velocity of a flexible body be defined? The main purpose of this paper is to define the angular velocity and the rotational axis of a whole flexible body system. A family of compact generalized formulations of rotational motion for a flexible body or multibody is derived by adopting an instantaneous rotational axis of the whole body. Here, the current angular momentum of the whole flexible system is equated with the sum of the individual angular momentum on each element over the system. As an example, simulation of a motion analysis of human body on a sport, especially throwing motion analysis of a shot put, is carried out in order to verify the derived equations in the paper

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In this paper a lumped mass model was used to simulate the behavior of the human body during vertical vibration. Force method as been used to obtain the differential equations of the model, which were solved using simulink toolbox of Matlab software the appropriate damping and stiffness coefficients of shoes were chosen by comparing the results with the experimental data. The model has been used to produce a useful package, which has various abilities. We obtained the kinematics characteristics for each links of the model, in response of sine wave stimulation. This package has also the ability of comparing results by changing the damping and stiffness coefficients for the contact point (shoe) of the model. One of the important specifications of the package is its flexibility. With a little change in the codes of the program we can obtain the curves in response of other kinds of stimulations like noises and pulses.

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This paper deals with a new countermeasure against wind-induced cable vibrations called "changing vibration modes method", in which growth of the unstable fundamental vibration mode is suppressed by dissipating vibration energy in higher mode generated by a permanent magnet installed near the lower end of the cable. In this paper, first, a parameter design method for "changing vibration modes method" is proposed and we showed its effectiveness by simulation results. Second, the proof that this countermeasure was effective against rain-wind induced vibration is demonstrated by trial application to an actual bridge.

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