Pneumatic rubber artificial muscles are nearly ideal for power assistance, medical care, and rehabilitation due to their lightweight drive unit made of rubber, which is soft and safe for human use. However, they have complex nonlinearities, including input saturation, hysteresis, and changes in static characteristics due to shrinkage. Additionally, when used with a human subject, the artificial muscle control system’s characteristics may vary based on the person’s physique, fitness, temperature, and the rubber’s deterioration. Therefore, it is desirable to be able to auto-tune the PID and other controllers in a short time before use. Data-driven controls such as FRIT and VRFT are suitable for auto-tuning in a short time. Among them, V-Tiger presented a procedure for predicting the actual closed-loop response and its Confidence interval. However, V-Tiger is not applicable to nonlinear systems with input saturation. This paper describes a procedure for (1) tuning PID gains by predicting the closed-loop response with V-Tiger in the presence of input saturation, (2) obtaining Confidence intervals for the predicted response affected by input saturation, and (3) how to use the Confidence intervals to apply this method to nonlinear systems.

Fictitious Reference Iterative Tuning (FRIT) have been reported for many applications, in which the control gain can be optimized so that the closed loop system corresponds with the reference model based on only one experiment data. However, when the reference model is not appropriate, there is a problem that not only the control performance is deteriorated but also the control system may become unstable. Instead of using model matching to the closed-loop reference model, we thought that this problem could be solved by optimizing the settling time and overshoot. To measure settling time and overshoot, the time response is required. The time response can be predicted using Kaneko's method [Takahashi, 2019], but this method requires the order of the closed loop transfer function. In this paper, the method [Takahashi, 2019] is reconsidered as a frequency response based method so that the order is not required. Furthermore, as another approach of FRIT, this paper proposes a method called ‘Virtual Time-response based Iterative Gain Evaluation and Redesign’ (V-Tiger) which iterates to measure the overshoot and settling time from the virtual time responses, and to evaluate and redesign the controller gain.

Since Artificial Intelligence (AI) has won over human pros such as Chess, Shogi and Go, expectations for AI have been increasing dramatically. One of the reasons why AI has developed so much is the tremendous increase in the processing speed of computers, which makes it possible to virtually repeat simulated competitions such as Othello, Shogi, Go and so on in the computer very fast. Finally, AI has gained strength over human pros. Also in control engineering, if gain tuning experiments of controllers can be virtually performed in a computer, it can be expected to dramatically improve control performance with an AI-like approach. This paper proposes a new method called 'Virtual Time-response based Iterative Gain Evaluation and Redesign' (V-Tiger) which iterates: 1) to calculate virtual time responses of the closed-loop system when a certain controller is inserted based on one-shot experimental data, 2) to measure the overshoot and settling time from the virtual time responses, and 3) to evaluate and redesign the controller gain considering the stability margin.

© 2017, Fuji Technology Press. All rights reserved. This study develops teaching materials for mechatronics in higher education. Industrial societies require numerous mechatronics engineers, and most technical universities provide mechatronics exercises in their curriculums. However, it is difficult for teachers and students to modify and improve the mechatronic teaching materials because the provided materials are finished products. Therefore, a simple and inexpensive educational system is developed to overcome the disadvantages of the finished products. In this paper, an experimental apparatus is proposed for mechatronics education, and a practical example is presented that involves learning control methods, sensors, actuators, and mechanics.

© 2017 IEEE. Bio-information is important to confirm the body condition. Especially, the muscle fatigue is related to injury or decrease of concentration. Therefore, it is required to evaluate muscle fatigue to make subject enjoy sports. In previous study, muscle fatigue is evaluated by using electromyogram (EMG). However, the electrode for EMG measurement is generally used for contact manor. The electrodes are disposable and it might cause the irritation of skin. Therefore, it isn't fitted for measurement of muscle fatigue. We developed wearable muscle fatigue detection system using capacitance coupling electrodes. Developed system isn't caused the irritation by electrodes and can reuse it. We compared the conventional system using disposable electrode system and our system to evaluate performance. We evaluated muscle fatigue from electromyogram before and after futsal. An integrated electromyogram and an intermediate frequency were used for the evaluation of muscle fatigue. As a result, half of subjects showed tendency of muscle fatigue. Therefore, we showed the possibility as muscle fatigue detection system using the capacity coupling electrodes.

Bio-information is important to confirm the body condition. Especially, the muscle fatigue is related to injury or decrease of concentration. Therefore, it is required to evaluate muscle fatigue to make subject enjoy sports. In previous study, muscle fatigue is evaluated by using electromyogram (EMG). However, the electrode for EMG measurement is generally used for contact manor. The electrodes are disposable and it might cause the irritation of skin. Therefore, it isn't fitted for measurement of muscle fatigue. We developed wearable muscle fatigue detection system using capacitance coupling electrodes. Developed system isn't caused the irritation by electrodes and can reuse it. We compared the conventional system using disposable electrode system and our system to evaluate performance. We evaluated muscle fatigue from electromyogram before and after futsal. An integrated electromyogram and an intermediate frequency were used for the evaluation of muscle fatigue. As a result, half of subjects showed tendency of muscle fatigue. Therefore, we showed the possibility as muscle fatigue detection system using the capacity coupling electrodes.

© 1999 EUCA. It is useful for the system engineer to initialize the tuning parameters of the adaptive control automatically. The adaptation gain and the width of the dead zone are the tuning parameters of the estimation law using the dead zone, and the control law also has additional tuning parameters. In this paper, we propose a new automatic initialization method of an adaptive control with a few tuning parameters that are determined by input and output data measured a priori. The width of dead zone in the estimation law is changed at each iteration depending on the input signal by the function determined by a priori input and output signals. The control law used here is an H∞-suboptimal one referring to complementary sensitivity function against unstructured uncertainty. Furthermore, we apply the proposed method to the electro-hydraulic servo system and verify the effects by an experiment.

The proof of Nyquist's criterion for stability requires the assumption that frequency s goes along the closed contour enclosing the right-half complex plane in a clockwise direction. This paper presents a new proof that does not require the assumption.

It is useful to develop robots that can be used instead of guide dogs because the number of the guide dogs is significantly less than that of visually impaired humans demand. This paper describes desired capacity for locomotion such as walking speed and climbing steps that the guide dog robots should have in the practical use in daily life, and proposes the way to stabilize the posture of the robot by controlling roll, pitch and yaw angle detected by a gyro-sensor mounted in the trunk. The guide dog robot is manufactured and verified the practicability by experiments of walking and climbing a step. © 2013 Springer-Verlag GmbH.

The proof of Nyquist's criterion for stability requires the assumption that frequency goes along the closed contour enclosing the right-half complex plane in a clockwise direction. This paper presents a new simple proof that does not require the assumption.© International Science Press.

It is known that some rotational machines such as compressors, pumps and so on often generate noises and vibrations due to periodic disturbances synchronised with the rotational speed. Vibration suppressing systems such as repetitive control are known to be effective to suppress the periodic disturbances. However, the control input of the repetitive controller may become larger and larger when the control input is saturated. This paper designs a generalised disturbance observer using the internal model principle that is effective to suppress periodic disturbances, and proposes a method that can make control performance deterioration minimal even if the control inputs are saturated. First, the proposed system estimates disturbances using the disturbance observer. Next, the estimated disturbances are passed into a filter of which the gain is one and phase lag is zero at the disturbance's frequencies, and are added into the control input in order to cancel the periodic disturbance. This filter is designed using the internal model principle, and the reason is explained why the filter should not be set to one. Some motor system simulations show that the phase lag of the estimated disturbances correspond to that of the periodic disturbances so that the method can make control performance deterioration minimal. The method is appropriate to rotational machine systems such as compressors and pumps in which the vibrations and noises should be avoided.

It is known that some rotational machines such as compressors, pumps and so on often generate noises and vibrations due to periodic disturbances synchronised with the rotational speed. Vibration suppressing systems such as repetitive control are known to be effective to suppress the periodic disturbances. However, the control input of the repetitive controller may become larger and larger when the control input is saturated. This paper designs a generalised disturbance observer using the internal model principle that is effective to suppress periodic disturbances, and proposes a method that can make control performance deterioration minimal even if the control inputs are saturated. First, the proposed system estimates disturbances using the disturbance observer. Next, the estimated disturbances are passed into a filter of which the gain is one and phase in is zero at the disturbance's frequencies, and are added into the control input in order to cancel the periodic disturbance. This filter is designed using the internal model principle, and the reason is explained why the filter should not be set to one. Some motor system simulations show that the phase lag of the estimated disturbances correspond to that of the periodic disturbances so that the method can make control performance deterioration minimal. The method is appropriate to rotational machine systems such as compressors and pumps in which the vibrations and noises should be avoided.

In this paper, a new parameter identification method for Interior Permanent Magnet Synchronous Motor (IPMSM) sensorless control is proposed. Noise and vibration in mechanical plant is increased if rotor position estimation error occurs. Furthermore, the rotor position estimation error causes noise and vibration. When load torque and reference motor speed are constant, and phase voltages and phase currents in multiple stationary states are measured, motor parameters can be identified even if an estimated rotor position does not correspond with the actual rotor position. Furthermore, this paper proposes a new sensorless control method that derives the position by solving the motor voltage equation. It is shown that the method is able to estimate the true position even if the motor is in acceleration. Numerical simulations with the implementation of a Pulse Width Modulation (PWM) inverter are illustrated to verify the effect of the methods.

Andrews et. al. developed an indoor rowing system for paraplegia using functional electrical stimulation (FES), and presented that the system was safe and healthy for paraplegia. However, the system would be better if the following three terms are improved: Firstly, only quadriceps and hamstrings in both thighs are activated by FES. Secondly, in order to switch FES, it is required to push periodically manual on-off FES switches set on a handle bar at effective timing in every rowing cycle. That might lead to fail to operate switches. Thirdly, constant FES intensity is used, which causes early muscles fatigues and strong pains. This paper describes the following improvements for the system: Firstly, by using gastrocnemius in calf and anterior tibialis in shank in addition, rowing speed is raised. Secondly, switching FES on and off is automated, which avoid failure to operate switches. Thirdly, the intensity for FES is adjusted automatically, which lead to relieve early fatigues and pains. © 2009 IEEE.

Noises and vibrations are often generated by periodic disturbances in compressors, pumps and so on. It is well known that vibration suppressing systems such as the repetitive control effectively suppress the periodic disturbances. However, there is no report about methods that can make control performance deterioration as small as possible when control inputs of the vibration suppression system are saturated. This paper designs a disturbance observer that effectively suppresses periodic disturbances. The proposed method can accurately estimate the disturbance if one of the following two conditions is satisfied. The one is that the control object is known, and the other is that the input is not saturated. The control object is assumed to be a linear system that may have time-delay element and handle multi-input and multi-output. The proposed system estimates disturbances using the structure of the disturbance observer. Some compressors system simulations are illustrated to verify the effectiveness of the method. The method is appropriate to rotational machine systems such as compressors and pumps in which the vibrations and noises should be avoided.

Compressors, pumps etc often generate noise and vibration due to periodic disturbances. It is known that vibration suppressing systems such as repetitive control are effective in suppressing periodic disturbances. However, there is no report about methods that can make control performance deterioration as small as possible when the control inputs of the vibration suppression system are saturated. This paper develops a disturbance observer that is effectively suppressing periodic disturbances, and proposes a method that can make control performance deterioration minimal even if the control inputs are saturated. First, the proposed system estimates disturbances using the disturbance observer. Next the estimated disturbances are passed into a filter of unity gain and zero phase change at the disturbance's frequencies, and are added into the control input in order to cancel the periodic disturbance. Some motor system simulations show that the phase of the estimated disturbances corresponds to that of the periodic disturbances so that the method can make control performance deterioration minimal. The method is appropriate to rotational machine systems such as compressors and pumps in which vibration and noise should be avoided.

Control performance of vibration suppression system using the internal model principle deteriorates when control inputs are saturated. This paper describes a method that accurately estimates periodic disturbances when the inputs are saturated under the condition that the control object is known.

In this paper, we propose a new anti-windup method with an initialization procedure that avoids overshoot in spite of saturation of control input. This method is based on a two-degree-of-freedom model matching (MM) control system. Instead of the control input and reference output, which are not affected by input saturation, the saturated control input and an output are used respectively for updating the reference output and feedforward input. Thereby, when the input becomes unsaturated, MM works well because the memorized values of the reference output that are used for updating the reference output correspond with the past output values. Furthermore, a procedure to initialize the reference model making the overshoots small is presented, even if the given control input is saturated. This method is adequate for systems in which overshoots are prohibited, such as temperature controls and machine tools. The effectiveness of the proposed method was verified using numerical simulations and experiments.

In this paper, we propose a new deterministic off-line identification method that obtains a state-space model by using input and output data with steady state values. This method is composed of the method, M. Kosaka, K. Koizumi and H. Shibata Transactions of the Society of Instrument and Control Engineers 36(4), 2000, 319-327. zeroing the 0 ∼ N-tuple integral values of output error of single-input single-output transfer function model and Ho-Kalman's method, H.P. Zeiger and A.J. Mc Ewen, IEEE Transactions on Automatic Control, AC 19-2, 1974, 153. The feature is that this method can identify by using step responses and, consequently, this is suitable for mechanical system identification in which noise and vibration are undesirable. Numerical simulations of multi-input multi-output system identification and experimental results are illustrated.

Compressors, pumps etc often generate noise and vibration due to periodic disturbances. It is known that vibration suppressing systems such as repetitive control are effective in suppressing periodic disturbances. However, there is no report about methods that can make control performance deterioration as small as possible when the control inputs of the vibration suppression system are saturated. This paper develops a disturbance observer that is effectively suppressing periodic disturbances, and proposes a method that can make control performance deterioration minimal even if the control inputs are saturated. First, the proposed system estimates disturbances using the disturbance observer. Next the estimated disturbances are passed into a filter of unity gain and zero phase change at the disturbance's frequencies, and are added into the control input in order to cancel the periodic disturbance. Some motor system simulations show that the phase of the estimated disturbances corresponds to that of the periodic disturbances so that the method can make control performance deterioration minimal. The method is appropriate to rotational machine systems such as compressors and pumps in which vibration and noise should be avoided.

In this paper, we propose a new anti-windup method with a clear procedure of initialization to avoid vibrations and overshoots in spite of saturation of the control input. This method is based on a single-input single-output 2 degree of freedom model matching control system and by using a switch, a saturated control input and an output are respectively used for updating a reference output and a feedforward input instead of a control input and a reference output; these are not affected by input saturation. By this means, even if the control input is saturated, the state of the reference model corresponds with that of the control object and at the moment the updated control input is not saturated, the output immediately corresponds with the reference output. Furthermore, a procedure to initialize the reference model by which vibrations and overshoots do not occur even if the control input is saturated, is given. This method is suitable for systems in which vibrations and overshoots are taboo, such as tool machines. The effectiveness of the proposed method is verified by numerical simulation.

In this paper, we propose a new anti-windup method with a clear procedure of initialization to avoid vibrations and overshoots in spite of saturation of the control input. This method is based on a single-input single-output 2 degree of freedom model matching control system and by using a switch, a saturated control input and an output are respectively used for updating a reference output and a feedforward input instead of a control input and a reference output; these are not affected by input saturation. By this means, even if the control input is saturated, the state of the reference model corresponds with that of the control object and at the moment the updated control input is not saturated, the output immediately corresponds with the reference output. Furthermore, a procedure to initialize the reference model by which vibrations and overshoots do not occur even if the control input is saturated, is given. This method is suitable for systems in which vibrations and overshoots are taboo, such as tool machines. The effectiveness of the proposed method is verified by numerical simulation.

In this paper, we propose a new anti-windup method with a clear procedure of initialization to avoid vibrations and overshoots in spite of saturation of the control input. This method is based on a single-input single-output 2 degree of freedom model matching control system and by using a switch, a saturated control input and an output are respectively used for updating a reference output and a feedforward input instead of a control input and a reference output; these are not affected by input saturation. By this means, even if the control input is saturated, the state of the reference model corresponds with that of the control object and at the moment the updated control input is not saturated, the output immediately corresponds with the reference output. Furthermore, a procedure to initialize the reference model by which vibrations and overshoots do not occur even if the control input is saturated, is given. This method is suitable for systems in which vibrations and overshoots are taboo, such as tool machines.The effectiveness of the proposed method is verified by numerical simulation.

This study proposes a new deterministic off-line identification method that obtains a state-space model using input and output data with steady state values. This method comprises of two methods: Zeroing the 0∼N-tuple integral values of the output error of single-input single-output transfer function model (Kosaka et al., 2004) and Ho-Kalman's method (Zeiger and McEwen, 1974). Herein, we present a new method to derive a matrix similar to the Hankel matrix using multi-input and multi-output data with steady state values. State space matrices A, B, C, and D are derived from the matrix by the method shown in Zeiger and McEwen, 1974 and Longman and Juang, 1989. This method's utility is that the derived state-space model is emphasized in the low frequency range under certain conditions. Its salient feature is that this method can identify use of step responses; consequently, it is suitable for linear mechanical system identification in which noise and vibration are unacceptable. Numerical simulations of multi-input multi-output system identification are illustrated. Copyright © 2006 by ASME.

This paper describe a discrete time off-line identification method performed by using input and output data having a constant steady state output response such as a step response. A step input causes noise or vibration from a mechanical system only at the moment when it is applied but they are attenuated asymptotically. The method can directly acquire any order of reduced model without knowing the real order of the plant. The effectiveness of the method is verified by applying it to a two-mass mechanical system.

It is useful for system engineers to initialize tuning parameters of adaptive control automatically. Adaptation gain and width of dead zone are tuning parameters of an estimation law using a dead zone. A control law has additional tuning parameters. This paper presents a new variable dead zone and a new automatic initialization method for adaptive control using a variable dead zone with a few tuning parameters that are determined by previously measured input and output data. The dead zone width in the estimation law is changed depending on the input signal by a rational function initialized using previously measured input and output signals. The control law used here is an H∞ control one referring to a complementary sensitivity function against unstructured uncertainty. We apply the proposed method to an electro-hydraulic servo system and verify the effects by experimentation.

This paper describe a discrete time off-line identification method performed by using input and output data having a constant steady state output response such as a step response. A step input causes noise or vibration from a mechanical system only at the moment when it is applied but they are attenuated asymptotically. The method can directly acquire any order of reduced model without knowing the real order of the plant. The effectiveness of the method is verified by applying it to a two-mass mechanical system.

This paper describes a control method that takes into account input saturations based on the structure of the two degree of freedom model matching control system. Concretely, a control method and a procedure are considered so that outputs of a control object track the reference outputs without occurring overshoot. The effectiveness of the method is verified by numerical simulations and experiments.

In this paper, we propose a new deterministic off-line identification method that delivers a state-space model by using input and output data with steady state values. This method combines the method zeroing the 0N-tuple integral values of output error of single-input single-output transfer function model and Ho-Kalman's method. The feature is that this method can identify by using step responses and, consequently, this is suitable for a mechanical system identification in which persistent fluctuations are unacceptable. Numerical simulations of multi-input multi-output system identification are illustrated and the practicability is verified by application to a pneumatic two link arm system.

In this paper, we propose a new anti-windup method with clear procedure of initialization to avoid overshoot in spite of saturation of control input. This method is based on a 2 degree of freedom model matching control system and by using a switch, instead of a control input and a reference output those are not affected by an input saturation, a saturated control input and an output are respectively used for updating a reference output and a feedforward input. By this means, when the input come to unsaturated, the Model Matching works correctly because the memorized values of the reference output utilized for updating reference output correspond with the past values of the output. Furthermore, a procedure to initialize the reference model with which the overshoots do not occur even if the control input is saturated is given. This method is suitable for systems in which overshoots are taboo such as tool machines and temperature controls. The proposed method is verified the effectiveness by numerical simulations and experiments.

In this paper, we propose a new anti-windup method with clear procedure of initialization to avoid overshoot in spite of saturation of control input. This method is based on a 2 degree of freedom model matching control system and by using a switch, instead of a control input and a reference output those are not affected by an input saturation, a saturated control input and an output are respectively used for updating a reference output and a feedforward input. By this means, when the input come to unsaturated, the Model Matching works correctly because the memorized values of the reference output utilized for updating reference output correspond with the past values of the output. Furthermore, a procedure to initialize the reference model with which the overshoots do not occur even if the control input is saturated is given. This method is suitable for systems in which overshoots are taboo such as tool machines and temperature controls. The proposed method is verified the effectiveness by numerical simulations and experiments.

In this paper, we propose a deterministic off-line identification method performed by using input and output data with a constant steady state output response such as a step response that causes noise or vibration from a mechanical system at the moment when it is applied but they are attenuated asymptotically. The method can directly acquire any order of reduced model without knowing the real order of a plant, in such a way that the intermediate parameters are uniquely determined so as to be orthogonal with respect to 0 - N-tuple integral values of output error and irrelevant to the unmodelled dynamics. From the intermediate parameters, the coefficients of a rational transfer function are calculated. In consequence, the method can be executed for any plant without knowing or estimating its order at the beginning. The effectiveness of the method is illustrated by numerical simulations and also by applying it to a 2-mass system.

This work describes an anti-windup method for a feedforward controller of two-degree-of-freedom (2DOF) control by which model matching is done. The proposed method replaces the memorized variable of output of the reference model in the feedforward controller with a controlled variable when input is saturated. Furthermore, the authors propose deriving a model of a controlled object using identification method for a reduced model with zeroing 0 ∼ N-tuple integral values of output error. Using the model, tracking error for reference input that consists of 0 ∼ N-th power of time becomes zero even if the controlled object has uncertainty. The resulting system shows no deterioration in feedback characteristics or increases in tuning labour time because feedforward controllers do not affect feedback characteristics; moreover, feedback controllers can be designed with accumulated knowhow. Numerical simulations and experiment verify that the proposed method yields satisfactory reference input response even if input is saturated or when the controlled object has uncertainty.

In this paper, we propose a deterministic off-line identification method performed by using input and output data with a constant steady state output response such as a step response that causes noise or vibration from a mechanical system at the moment when it is applied but they are attenuated asymptotically. The method can directly acquire any order of reduced model without knowing the real order of a plant, in such a way that the intermediate parameters are uniquely determined so as to be orthogonal with respect to 0 similar to N-tuple integral values of output error and irrelevant to the unmodelled dynamics. From the intermediate parameters, the coefficients of a rational transfer function are calculated. In consequence, the method can be executed for any plant without knowing or estimating its order at the beginning. The effectiveness of the method is illustrated by numerical simulations and also by applying it to a 2-mass system.

In this paper, we propose a deterministic off-line identification method performed by using input and output data with a constant steady-state output response. The method can directly acquire any order of reduced model without knowing the real order of a plant, in such a way that the intermediate parameters are uniquely determined so as to be orthogonal with respect to O-N-tuple integral values of output error and irrelevant to the un-modeled dynamics. From the intermediate parameters, the co-efficients of a rational transfer function are calculated. In consequence, the method can be executed for any linear single-input single-output plant without knowing or estimating its order at the beginning. The effectiveness of the method is illustrated by numerical simulations and also by applying it to a two-mass system. Copyright © 2004 by ASME.

In this paper, a new sensorless Interior Permanent Magnet Synchronous Motor (IPMSM) drive method with Extended Kalman Filtering (EKF) estimation of speed and rotor position is proposed. This method is on the basis of the sensorless Surface Permanent Magnet Synchronous Motor (SPMSM) drive [1] that can be applied to motors with no salient pole and is developed so as to be able to be applied to motors with salient pole such as IPMSM. The feature of the method is that rotor position estimation error does not occur even if motor current or motor voltage changes. Therefore, the method can be applied with arbitrary motor voltage waveform and, consequently, the method is suitable for sensorless IPMSM drive.
Numerical simulations are illustrated to verify the effect of the method.

Copyright © 2004 IFAC. In this paper, a new sensorless Interior Permanent Magnet Synchronous Motor (IPMSM) drive method with Extended Kalman Filtering (EKF) estimation of rotor position is proposed. This method is on the basis of the sensorless IPMSM drive (Kosaka et. al., 2003). The feature of the method is that the order of the state variables of propased method is less than that of the conventional method (Kosaka et. al., 2003). Therefore, computational load and calculation error of matrices in the EKF can be decreased. Numerical simulations are illustrated to verify the effect of the method.

It is useful for the system engineer to initialize the tuning parameters of an adaptive control automatically because less experienced engineers often cause excessive noise and vibration from mechanical plants in the parameter initializing experiment. The adaptation gain and the width of the dead zone are the tuning parameters of the estimation law using the dead zone, and the control law also has additional tuning parameters. In this paper, we propose a new automatic initialization method for an adaptive control with a few tuning parameters that are determined by previously measured input and output data. The width of the dead zone in the estimation law is changed at each iteration depending on the input signal by the function determined by previously measured input and output signals. The control law used here is an H∞ control one [3] that stabilizes the control system and minimizes a kind of H∞ norm of the sensitivity function and the complementary sensitivity function if the upper bound of the unstructured uncertainty of the control object is known. Furthermore, we apply the proposed method to an electro-hydraulic servo system and verify the effects by an experiment.

It is useful for the system engineer to initialize the tuning parameters of an adaptive control automatically because less experienced engineers often cause excessive noise and vibration from mechanical plants in the parameter initializing experiment. The adaptation gain and the width of the dead zone are the tuning parameters of the estimation law using the dead zone, and the control law also has additional tuning parameters. In this paper, we propose a new automatic initialization method for an adaptive control with a few tuning parameters that are determined by previously measured input and output data. The width of the dead zone in the estimation law is changed at each iteration depending on the input signal by the function determined by previously measured input and output signals. The control law used here is an H-infinity control one [3] that stabilizes the control system and minimizes a kind of H-infinity norm of the sensitivity function and the complementary sensitivity function if the upper bound of the unstructured uncertainty of the control object is known. Furthermore, we apply the proposed method to an electro-hydraulic servo system and verify the effects by an experiment.

In this paper, a new sensorless Interior Permanent Magnet Synchronous Motor (IPMSM) drive method with Extended Kalman Filtering (EKF) estimation of speed and rotor position is proposed. This method is on the basis of the sensorless Surface Permanent Magnet Synchronous Motor (SPMSM) drive [1] that can be applied to motors with no salient pole and is developed so as to be able to be applied to motors with salient pole such as IPMSM. Noise and vibration in mechanical plant becomes larger if rotor position estimation error occurs. Furthermore, the rotor position estimation error causes noise and vibration. The feature of the method is that rotor position estimation error does not occur even if motor current or motor voltage change. Therefore, the method can be applied with arbitrary motor voltage waveform and, consequently, the method is suitable for sensorless IPMSM drive. Numerical simulations are illustrated to verify the effect of the method.

In this paper, a new sensorless Interior Permanent Magnet Synchronous Motor (IPMSM) drive method with Extended Kalman Filtering (EKF) estimation of speed and rotor position is proposed. This method is on the basis of the sensorless Surface Permanent Magnet Synchronous Motor (SPMSM) drive that can be applied to motors with no salient pole and is developed so as to be able to be applied to motors with salient pole such as IPMSM. The feature of the method is that rotor position estimation error does not occur even if motor current or motor voltage change. Therefore, the method can be applied with arbitrary motor voltage waveform and, consequently, the method is suitable for sensorless IPMSM drive. Numerical simulations are illustrated to verify the effect of the method.

Polycrystalline CdS thin films have been deposited on borosilicate glass substrates coated with ITO film by metalorganic chemical vapor deposition using dimethyl cadmium and diethyl sulfide as source materials. The growth of CdS film occurred at substrate temperatures within the range of 280-360°C. The deposition rate increased with increasing VI/II molar ratio at any substrate temperature and showed a maximum value at the VI/II molar ratio of 4. The grain size of as-deposited CdS film prepared at substrate temperatures from 300°C to 360°C was about 0.1μm. The CdS films consist of hexagonal form with a preferential orientation of the (002) plane parallel to the substrate. Thin CdS film with high optical transmittance was prepared at 350°C with the VI/II molar ratio of 4. The CdS film deposited by MOCVD may be used as a window layer for CdS/CdTe solar cell. © 2002 Elsevier Science B.V. All rights reserved.

This paper is concerned with a practical controller to suppress the periodic speed variation of a motor. Speed variation in a pump, a compressor or a wheel of an electric vehicle causes vibration and noise, which shorten the life of the machine. Although repetitive control can suppress the speed variation, there are the following problems: If a reference velocity changes, the period of the speed variation changes and the effect of the suppression is reduced. The tuning parameters are difficult to tune. In the case where a low-resolution angle sensor is used, the output of the controller to suppress the speed variation becomes pulse-shaped and causes harmonic ripples that increase energy consumption. In order to eliminate the harmonic ripples, we propose a controller of which the output is interpolated with a sine wave.

This paper is concerned with a practical controller to suppress the periodic speed variation of a motor. Speed variation in a pump, a compressor or a wheel of an electric vehicle causes vibration and noise, which shorten the life of the machine. Although repetitive control can suppress the speed variation, there are the following problems: If a reference velocity changes, the period of the speed variation changes and the effect of the suppression is reduced. The tuning parameters are difficult to tune. In the case where a low-resolution angle sensor is used, the output of the controller to suppress the speed variation becomes pulse-shaped and causes harmonic ripples that increase energy consumption. In order to eliminate the harmonic ripples, we propose a controller of which the output is interpolated with a sine wave.

An input signal, such as M series signal, used in the least square method is required to satisfy P.E. condition, which often results in resonance, and consequently large noise and vibration in a mechanical object, as in an oil hydraulic system. On the other hand, a step signal is practical because it causes less noise and vibration. Conventional off-line identification methods restrict the order of an identifiable model if a step signal is used for it.
In this paper, we propose a new off-line identification method, which can be applied to an arbitrary order object and performed with data generating constant steady state output response. The feature of the method is that a reduced order model can be obtained directly in the way that the intermediate parameters, from which the system parameters (coefficients of rational transfer function) are derived, are determined uniquely irrelevant to the unmodelled dynamics, so that 0∼N-tuple integral values of the output error lead to zero.
Numerical simulations indicate the effectiveness of the proposed method.

An electro-hydraulic servo system, which uses a proportional electromagnetic valve, has nonlinear static characteristics between the input voltage and output velocity. When positioning of the servo system is controlled with an integral factor, there appears a problem of a limit cycle. A conventional compensator adds a fixed value to the output of the controller, reduces amplitude of the limit cycle and obtains good response. But the static characteristics of the servo system change with oil pressure, position of slide and so on, which increases the amplitude of the limit cycle and leads to unsatisfactory response.
In this paper, a new on-line compensator is proposed. The compensator estimates some parameters of nonlinear characteristics from input and output data, and removes the unsatisfactory nonlinear static characteristics. The advantage of this compensator is examined through practical experiments of the servo system.

It is useful for control engineers to initialize automatically the tuning parameters of adaptive control by using a priori measured data without any trial and error.
The adaptive law using time varying gain matrix has better convergence rate than the one using fixed gain matrix. In order to be sensitive to characteristic change of control object, it is useful to use variable dead zone width which changes according to magnitude of disturbance.
In this paper, we propose a scaling type law having variable dead zone width and automatic initialization using a priori measured data. We prove a theorem that gives some properties and convergence of the algorithm, and illustrate how to determine the variable width by using data obtained from a priori measurement and at each iteration instant. The variable width is yielded by αd₀ (k), of which constant α and time variant d₀ (k) are respectively determined by a priori measured data and data calculated at each iteration.
Furthermore, we apply the above algorithm to identification of an electro-hydraulic servo system and verify the effects.

目標値フィルタにより零配置を行う新しい極零配置形適応制御方式を提案しその特徴を理論的に考察し, 従来の手法よりも利点をもつことをシミュレーションによって確認した.

It is effective for robust control design to evaluate complementary sensitivity function if the uncertainty of a controlled object is known. The conventional adaptive control with parameter estimation provides satisfactory control performance against parameter variation but it is not sufficiently robust against unstructured uncertainty. In this paper, we propose a combined adaptive control design referring to parameter estimation against parameter variation and complementary sensitivity function against unstructured uncertainty. The proposed method includes initial estimation of uncertainties using plant input and output, and its stability is proved for an overall adaptive system. The advantage of this design is that initial adjustment of parameters in control law needs little tuning. Experiments and simulations for an oil hydraulic system are performed to verify the effectiveness.

「わかる編」では制御工学でなにができるのか,またその手順や方法,制約などを説明する。「ナットク編」では高校数学の知識で制御工学の理論的な裏付けをし,最後の「役立つ編」では制御設計をシミュレーションし,制御を実感する。