Induction motors are widely used in transportation, mining, petrochemical, manufacturing and in a... more Induction motors are widely used in transportation, mining, petrochemical, manufacturing and in almost every other field dealing with electrical power. These motors are simple, efficient, highly robust and rugged thus offering a very high degree of reliability. But like any other machine, they are vulnerable to faults, which if left unmonitored, might lead to catastrophic failure of the machine in the long run. On-line condition monitoring of the induction motors has been widely used in the detection of faults. This paper delves into the various faults and study of conventional and innovative techniques for induction motor faults with an identification of future research areas.
Piezoelectric-stack actuated platforms are very popular in the parlance of nanopositioning with m... more Piezoelectric-stack actuated platforms are very popular in the parlance of nanopositioning with myriad applications like
micro/nanofactory, atomic force microscopy, scanning probe microscopy, wafer design, biological cell manipulation, and so forth. Motivated by the necessity to improve trajectory tracking in such applications, this paper addresses the problem of rate dependent hysteretic nonlinearity in piezoelectric actuators (PEA). The classical second order Dahl model for hysteresis encapsulation is introduced first, followed by the identification of parameters through particle swarm optimization. A novel inversion based feedforward mechanism in combination with a feedback compensator is proposed to achieve high-precision tracking wherein the paradoxical concept of noise as a performance enhancer is introduced in the realm of PZAs. Having observed that dither induced stochastic resonance in the presence of periodic forcing reduces tracking error, dither capability is further explored in conjunction with a novel output harmonics based adaptive control scheme.The proposed adaptive controller is then augmented with an internal
model control based approach to impart robustness against parametric variations and external disturbances.The proposed control law has been employed to track multifrequency signals with consistent compensation of rate dependent hysteresis of the PEA. The results indicate a greatly improved positioning accuracy along with considerable robustness achieved with the proposed integrated approach even for dual axis tracking applications.
With the rapid growth of power system and the increase in their complexity of the networks, load ... more With the rapid growth of power system and the increase in their complexity of the networks, load forecasting plays a vital role in economic operation of power systems, network planning and infrastructure development. Electricity demand forecasting is concerned with the prediction of a very short term, short term, medium term and long term load demand, depending on the time horizon. This paper presents an application of neural network for real time short term load forecasting and has been compared with the conventional exponential smoothing technique. The daily load data of an inter connected grid Damodar Valley Corporation, operating under Eastern Regional Load Dispatch Centre, India were used as data sets for training and comparing the performance of different neural network topologies along with conventional exponential smoothing technique. The results obtained from Artificial Neural Networks were evaluated with the statistical parameters i.e., Mean Absolute Percentage Error (MAPE) and Mean Absolute Deviation (MAD). MATLAB has been used for simulation, performance and testing the data. Extensive testing shows that neural network based approach has better forecasting accuracy and robustness.
Power distribution systems play an important role in modern society. Increasing size and capacity... more Power distribution systems play an important role in modern society. Increasing size and capacity of power systems have rendered them more complex which in turn has led to reduced reliability of such systems. Power distribution systems are always prone to faults. Faults in power systems are generally due to short circuits, lightning etc. Fast and proper restorations of outages are crucial to improve system reliability. For quick and adequate recovery actions such as the determination of the propriety of carrying out forced line charging and the necessity of network switching, and an efficient patrolling, understanding the cause of a fault in an electric power system in the system operation is essential. Moreover, unknown faults may add to unnecessary costs if effective restorations and identifications can’t be done quickly. So, identification of a fault on a transmission line needs to be correct and rapid. However, recognition of the causes of distribution faults accurately generally lack in expert personnel. Also the knowledge about the nature of these faults is not easily transferable from person to person. So, effective means of fault identification needs to be encouraged. In this paper, some of the unconventional approaches for condition monitoring of power systems comprising of wavelet transform, along with the application of soft computing techniques like artificial neural networks, fuzzy logic, support vector machines, genetic algorithm and hybrid combinations based on these have been studied.
Piezo-actuated platforms are used in several nano positioning applications because of their high ... more Piezo-actuated platforms are used in several nano positioning applications because of their high resolution, large blocking force, high stiffness constant and quick response. But the intrinsic hysteretic nonlinearity considerably dampens their
performance. Dither based control is known to ameliorate
hysteresis in piezoelectric actuators. However, due to parametric variations and uncertainties, dither control alone cannot achieve the desired positional accuracy. In order to effectively implement any real-time control to alleviate the effects of nonlinearity, an adaptive mechanism is the utmost priority to update the control system. This paper explores the effects of hysteretic nonlinearity in a second order Dahl model based piezo-driven manipulator. The plant performance is known to improve with a suitable amount of injected noise. The concept of dither based control is cascaded with the conventional PID controller to bring out an innovative adaptive voltage control strategy. A dual axis piezo platform is taken into account for the controller design and validation. The performance of the controller is verified using certain tests. Results show an improved positioning accuracy of the manipulator with the proposed control scheme than without
it. The proposed control emerges as an effective control strategy to improve trajectory tracking accuracy.
Precision control of multi-axis piezo actuated micro / nanopositioning stages suffers not only fr... more Precision control of multi-axis piezo actuated micro / nanopositioning stages suffers not only from the inherent nonlinearities but also from parametric variations and uncertainties. In order to effectively implement any real-time control theory to mitigate the effects of nonlinearity, an adaptive mechanism to update the control system is a prerequisite. This paper investigates the effects of hysteretic nonlinearity in a second order Dahl model based piezoelectric manipulator. The plant performance is known to improve with injection of a suitable dose of noise called “dither”. The concept of dither based control is interwoven with the conventional PID controller to introduce a novel adaptive dither control strategy. A double axis piezo stage is considered for controller design and validation. The controller performance is ascertained using three specific tests - a) Tracking Error Test, b) Multi-frequency, multi-amplitude tracking test and c) Two-axis Circular Contour Tracking Test. Results show an enhanced positioning accuracy of the manipulator in the presence of proposed control scheme than without it. The proposed control transpires as an effective control to improve tracking accuracy and resist external disturbances.
Accurate and reliable fault detection in three phase induction motors is of great importance from... more Accurate and reliable fault detection in three phase induction motors is of great importance from economical perspective. This paper deals with the modeling of five different stator faults, viz. Single Phasing, Single line to ground fault, over-voltage, under-voltage and voltage unbalancing. As part of data acquisition, stator phase current values are recorded during healthy condition as well as during various faults. Multiscale Permutation Entropy is introduced to extract the statistical data from the phase current signal. The extracted information is used to train a Time-Delay Neural Network which acts as a fault classifier. The accuracy of prediction and fault classification is ascertained in terms of two statistical parameters namely, Mean Absolute Percentage Error and Root Mean Squared Error. The proposed synergy of Multiscale Permutation Entropy and Time-Delay Neural Network proves to be a highly effective fault diagnosis platform for on-line implementation.
One of the most important tasks in industries is considered to be the condition monitoring of ind... more One of the most important tasks in industries is considered to be the condition monitoring of induction motors. However, most of the traditional methods employed for this purpose suffer from certain limitations in accomplishing this task. A successful implementation of condition monitoring requires the development of a simple but reliable detector of various faults. This paper investigates the performance of Discrete Wavelet Transform and Radial Basis Function based Neural Network for incipient stator fault diagnosis in induction motors. Wavelet analysis helps in the extraction of important features from the faulty signal and neural network classifies the fault type depending on the nature of fault. A mean absolute percentage error of 1.4236% between the actual values and the predicted values by the neural network show the effectiveness of the proposed approach.
This paper addresses the problem of hysteresis and presents a new control scheme for hysteresis c... more This paper addresses the problem of hysteresis and presents a new control scheme for hysteresis compensation of piezo-electrically actuated micro-nano manipulators. The technology employs an Inverse Dahl model based feed-forward mechanism in combination with a feedback control algorithm along with simultaneous voltage and displacement dither strategy. The actuator performance is seen to improve as a function of injected noise level into the plant – a phenomenon known as dithering. The notion of stochastic resonance for nano positioning is studied to determine the optimal dither level for
efficient plant performance. The efficacy of the proposed control scheme has been confirmed through rigorous simulations in terms of two specific tests – a) tracking error test and b) hysteresis curve area test. Results show an enhanced positioning precision of the manipulator with the proposed dither control than without it. Owing to its algorithmic simplicity, the proposed control genre can be extended to the parlance of other nano-scale applications.
Induction motors are widely used in transportation, mining, petrochemical, manufacturing and in a... more Induction motors are widely used in transportation, mining, petrochemical, manufacturing and in almost every other field dealing with electrical power. These motors are simple, efficient, highly robust and rugged thus offering a very high degree of reliability. But like any other machine, they are vulnerable to faults, which if left unmonitored, might lead to catastrophic failure of the machine in the long run. On-line
condition monitoring of the induction motors has been widely used in the detection of faults. This paper delves into the various faults and study of conventional and innovative techniques for induction motor faults with an identification of future research areas.
Hysteresis is a major impediment in achieving
precise position tracking through piezo actuated m... more Hysteresis is a major impediment in achieving
precise position tracking through piezo actuated micro nano
manipulator. In our study it has been shown that the effect of
hysteresis can be mitigated by the proper application of a
suitably selected dither sequence. The objective of the paper is to compare the various types of dither viz, Sinusoidal, Gaussian,
Rayleigh and Rician, as to which gives the optimal system
performance in terms of two tests- tracking error and area under the hysteresis curve. This paper starts with the analysis of a piezoelectric actuator based on the Dahl model. An inverse Dahl model based feed-forward mechanism in conjunction with a feedback control is used for the study of the actuator’s
performance. Dither injection is applied at three different places in the system and accordingly three different schemes namely displacement dither, voltage dither and combined dither have been developed and compared. Based on the simulations, the best type of dither and its corresponding intensity for a given place of dither injection has been established. Results ascertain dither based control as a simple and an efficient algorithm capable of providing very accurate micro-nano positioning.
Micro-nano positioning is a fast growing field in
the context of its modern day implications in ... more Micro-nano positioning is a fast growing field in
the context of its modern day implications in precision
engineering industry. However, this apparently indispensible
technique has its limitations imposed by the continuous
manifestation of non-linearitities like hysteresis and creep. This
work explores a relatively new control paradigm in the form of
dither to successfully neutralize hysteresis, in particular for a
Dahl Model based X-Y micro manipulator system working with
feed-forward control mechanism. The efficiency of different
dithers viz., Gaussian, Sinusoidal, Rician and Rayleigh have been
put to rigorous tests and the best dither has been established in terms of relative reduction of tracking error. It is observed that a combined displacement and voltage dither significantly improves system performance as compared to an undithered system.
Induction motors are widely used in transportation, mining, petrochemical, manufacturing and in a... more Induction motors are widely used in transportation, mining, petrochemical, manufacturing and in almost every other field dealing with electrical power. These motors are simple, efficient, highly robust and rugged thus offering a very high degree of reliability. But like any other machine, they are vulnerable to faults, which if left unmonitored, might lead to catastrophic failure of the machine in the long run. On-line condition monitoring of the induction motors has been widely used in the detection of faults. This paper delves into the various faults and study of conventional and innovative techniques for induction motor faults with an identification of future research areas.
Piezoelectric-stack actuated platforms are very popular in the parlance of nanopositioning with m... more Piezoelectric-stack actuated platforms are very popular in the parlance of nanopositioning with myriad applications like
micro/nanofactory, atomic force microscopy, scanning probe microscopy, wafer design, biological cell manipulation, and so forth. Motivated by the necessity to improve trajectory tracking in such applications, this paper addresses the problem of rate dependent hysteretic nonlinearity in piezoelectric actuators (PEA). The classical second order Dahl model for hysteresis encapsulation is introduced first, followed by the identification of parameters through particle swarm optimization. A novel inversion based feedforward mechanism in combination with a feedback compensator is proposed to achieve high-precision tracking wherein the paradoxical concept of noise as a performance enhancer is introduced in the realm of PZAs. Having observed that dither induced stochastic resonance in the presence of periodic forcing reduces tracking error, dither capability is further explored in conjunction with a novel output harmonics based adaptive control scheme.The proposed adaptive controller is then augmented with an internal
model control based approach to impart robustness against parametric variations and external disturbances.The proposed control law has been employed to track multifrequency signals with consistent compensation of rate dependent hysteresis of the PEA. The results indicate a greatly improved positioning accuracy along with considerable robustness achieved with the proposed integrated approach even for dual axis tracking applications.
With the rapid growth of power system and the increase in their complexity of the networks, load ... more With the rapid growth of power system and the increase in their complexity of the networks, load forecasting plays a vital role in economic operation of power systems, network planning and infrastructure development. Electricity demand forecasting is concerned with the prediction of a very short term, short term, medium term and long term load demand, depending on the time horizon. This paper presents an application of neural network for real time short term load forecasting and has been compared with the conventional exponential smoothing technique. The daily load data of an inter connected grid Damodar Valley Corporation, operating under Eastern Regional Load Dispatch Centre, India were used as data sets for training and comparing the performance of different neural network topologies along with conventional exponential smoothing technique. The results obtained from Artificial Neural Networks were evaluated with the statistical parameters i.e., Mean Absolute Percentage Error (MAPE) and Mean Absolute Deviation (MAD). MATLAB has been used for simulation, performance and testing the data. Extensive testing shows that neural network based approach has better forecasting accuracy and robustness.
Power distribution systems play an important role in modern society. Increasing size and capacity... more Power distribution systems play an important role in modern society. Increasing size and capacity of power systems have rendered them more complex which in turn has led to reduced reliability of such systems. Power distribution systems are always prone to faults. Faults in power systems are generally due to short circuits, lightning etc. Fast and proper restorations of outages are crucial to improve system reliability. For quick and adequate recovery actions such as the determination of the propriety of carrying out forced line charging and the necessity of network switching, and an efficient patrolling, understanding the cause of a fault in an electric power system in the system operation is essential. Moreover, unknown faults may add to unnecessary costs if effective restorations and identifications can’t be done quickly. So, identification of a fault on a transmission line needs to be correct and rapid. However, recognition of the causes of distribution faults accurately generally lack in expert personnel. Also the knowledge about the nature of these faults is not easily transferable from person to person. So, effective means of fault identification needs to be encouraged. In this paper, some of the unconventional approaches for condition monitoring of power systems comprising of wavelet transform, along with the application of soft computing techniques like artificial neural networks, fuzzy logic, support vector machines, genetic algorithm and hybrid combinations based on these have been studied.
Piezo-actuated platforms are used in several nano positioning applications because of their high ... more Piezo-actuated platforms are used in several nano positioning applications because of their high resolution, large blocking force, high stiffness constant and quick response. But the intrinsic hysteretic nonlinearity considerably dampens their
performance. Dither based control is known to ameliorate
hysteresis in piezoelectric actuators. However, due to parametric variations and uncertainties, dither control alone cannot achieve the desired positional accuracy. In order to effectively implement any real-time control to alleviate the effects of nonlinearity, an adaptive mechanism is the utmost priority to update the control system. This paper explores the effects of hysteretic nonlinearity in a second order Dahl model based piezo-driven manipulator. The plant performance is known to improve with a suitable amount of injected noise. The concept of dither based control is cascaded with the conventional PID controller to bring out an innovative adaptive voltage control strategy. A dual axis piezo platform is taken into account for the controller design and validation. The performance of the controller is verified using certain tests. Results show an improved positioning accuracy of the manipulator with the proposed control scheme than without
it. The proposed control emerges as an effective control strategy to improve trajectory tracking accuracy.
Precision control of multi-axis piezo actuated micro / nanopositioning stages suffers not only fr... more Precision control of multi-axis piezo actuated micro / nanopositioning stages suffers not only from the inherent nonlinearities but also from parametric variations and uncertainties. In order to effectively implement any real-time control theory to mitigate the effects of nonlinearity, an adaptive mechanism to update the control system is a prerequisite. This paper investigates the effects of hysteretic nonlinearity in a second order Dahl model based piezoelectric manipulator. The plant performance is known to improve with injection of a suitable dose of noise called “dither”. The concept of dither based control is interwoven with the conventional PID controller to introduce a novel adaptive dither control strategy. A double axis piezo stage is considered for controller design and validation. The controller performance is ascertained using three specific tests - a) Tracking Error Test, b) Multi-frequency, multi-amplitude tracking test and c) Two-axis Circular Contour Tracking Test. Results show an enhanced positioning accuracy of the manipulator in the presence of proposed control scheme than without it. The proposed control transpires as an effective control to improve tracking accuracy and resist external disturbances.
Accurate and reliable fault detection in three phase induction motors is of great importance from... more Accurate and reliable fault detection in three phase induction motors is of great importance from economical perspective. This paper deals with the modeling of five different stator faults, viz. Single Phasing, Single line to ground fault, over-voltage, under-voltage and voltage unbalancing. As part of data acquisition, stator phase current values are recorded during healthy condition as well as during various faults. Multiscale Permutation Entropy is introduced to extract the statistical data from the phase current signal. The extracted information is used to train a Time-Delay Neural Network which acts as a fault classifier. The accuracy of prediction and fault classification is ascertained in terms of two statistical parameters namely, Mean Absolute Percentage Error and Root Mean Squared Error. The proposed synergy of Multiscale Permutation Entropy and Time-Delay Neural Network proves to be a highly effective fault diagnosis platform for on-line implementation.
One of the most important tasks in industries is considered to be the condition monitoring of ind... more One of the most important tasks in industries is considered to be the condition monitoring of induction motors. However, most of the traditional methods employed for this purpose suffer from certain limitations in accomplishing this task. A successful implementation of condition monitoring requires the development of a simple but reliable detector of various faults. This paper investigates the performance of Discrete Wavelet Transform and Radial Basis Function based Neural Network for incipient stator fault diagnosis in induction motors. Wavelet analysis helps in the extraction of important features from the faulty signal and neural network classifies the fault type depending on the nature of fault. A mean absolute percentage error of 1.4236% between the actual values and the predicted values by the neural network show the effectiveness of the proposed approach.
This paper addresses the problem of hysteresis and presents a new control scheme for hysteresis c... more This paper addresses the problem of hysteresis and presents a new control scheme for hysteresis compensation of piezo-electrically actuated micro-nano manipulators. The technology employs an Inverse Dahl model based feed-forward mechanism in combination with a feedback control algorithm along with simultaneous voltage and displacement dither strategy. The actuator performance is seen to improve as a function of injected noise level into the plant – a phenomenon known as dithering. The notion of stochastic resonance for nano positioning is studied to determine the optimal dither level for
efficient plant performance. The efficacy of the proposed control scheme has been confirmed through rigorous simulations in terms of two specific tests – a) tracking error test and b) hysteresis curve area test. Results show an enhanced positioning precision of the manipulator with the proposed dither control than without it. Owing to its algorithmic simplicity, the proposed control genre can be extended to the parlance of other nano-scale applications.
Induction motors are widely used in transportation, mining, petrochemical, manufacturing and in a... more Induction motors are widely used in transportation, mining, petrochemical, manufacturing and in almost every other field dealing with electrical power. These motors are simple, efficient, highly robust and rugged thus offering a very high degree of reliability. But like any other machine, they are vulnerable to faults, which if left unmonitored, might lead to catastrophic failure of the machine in the long run. On-line
condition monitoring of the induction motors has been widely used in the detection of faults. This paper delves into the various faults and study of conventional and innovative techniques for induction motor faults with an identification of future research areas.
Hysteresis is a major impediment in achieving
precise position tracking through piezo actuated m... more Hysteresis is a major impediment in achieving
precise position tracking through piezo actuated micro nano
manipulator. In our study it has been shown that the effect of
hysteresis can be mitigated by the proper application of a
suitably selected dither sequence. The objective of the paper is to compare the various types of dither viz, Sinusoidal, Gaussian,
Rayleigh and Rician, as to which gives the optimal system
performance in terms of two tests- tracking error and area under the hysteresis curve. This paper starts with the analysis of a piezoelectric actuator based on the Dahl model. An inverse Dahl model based feed-forward mechanism in conjunction with a feedback control is used for the study of the actuator’s
performance. Dither injection is applied at three different places in the system and accordingly three different schemes namely displacement dither, voltage dither and combined dither have been developed and compared. Based on the simulations, the best type of dither and its corresponding intensity for a given place of dither injection has been established. Results ascertain dither based control as a simple and an efficient algorithm capable of providing very accurate micro-nano positioning.
Micro-nano positioning is a fast growing field in
the context of its modern day implications in ... more Micro-nano positioning is a fast growing field in
the context of its modern day implications in precision
engineering industry. However, this apparently indispensible
technique has its limitations imposed by the continuous
manifestation of non-linearitities like hysteresis and creep. This
work explores a relatively new control paradigm in the form of
dither to successfully neutralize hysteresis, in particular for a
Dahl Model based X-Y micro manipulator system working with
feed-forward control mechanism. The efficiency of different
dithers viz., Gaussian, Sinusoidal, Rician and Rayleigh have been
put to rigorous tests and the best dither has been established in terms of relative reduction of tracking error. It is observed that a combined displacement and voltage dither significantly improves system performance as compared to an undithered system.
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every other field dealing with electrical power. These motors are simple, efficient, highly robust and rugged
thus offering a very high degree of reliability. But like any other machine, they are vulnerable to faults,
which if left unmonitored, might lead to catastrophic failure of the machine in the long run. On-line
condition monitoring of the induction motors has been widely used in the detection of faults. This paper
delves into the various faults and study of conventional and innovative techniques for induction motor
faults with an identification of future research areas.
micro/nanofactory, atomic force microscopy, scanning probe microscopy, wafer design, biological cell manipulation, and so forth. Motivated by the necessity to improve trajectory tracking in such applications, this paper addresses the problem of rate dependent hysteretic nonlinearity in piezoelectric actuators (PEA). The classical second order Dahl model for hysteresis encapsulation is introduced first, followed by the identification of parameters through particle swarm optimization. A novel inversion based feedforward mechanism in combination with a feedback compensator is proposed to achieve high-precision tracking wherein the paradoxical concept of noise as a performance enhancer is introduced in the realm of PZAs. Having observed that dither induced stochastic resonance in the presence of periodic forcing reduces tracking error, dither capability is further explored in conjunction with a novel output harmonics based adaptive control scheme.The proposed adaptive controller is then augmented with an internal
model control based approach to impart robustness against parametric variations and external disturbances.The proposed control law has been employed to track multifrequency signals with consistent compensation of rate dependent hysteresis of the PEA. The results indicate a greatly improved positioning accuracy along with considerable robustness achieved with the proposed integrated approach even for dual axis tracking applications.
performance. Dither based control is known to ameliorate
hysteresis in piezoelectric actuators. However, due to parametric variations and uncertainties, dither control alone cannot achieve the desired positional accuracy. In order to effectively implement any real-time control to alleviate the effects of nonlinearity, an adaptive mechanism is the utmost priority to update the control system. This paper explores the effects of hysteretic nonlinearity in a second order Dahl model based piezo-driven manipulator. The plant performance is known to improve with a suitable amount of injected noise. The concept of dither based control is cascaded with the conventional PID controller to bring out an innovative adaptive voltage control strategy. A dual axis piezo platform is taken into account for the controller design and validation. The performance of the controller is verified using certain tests. Results show an improved positioning accuracy of the manipulator with the proposed control scheme than without
it. The proposed control emerges as an effective control strategy to improve trajectory tracking accuracy.
efficient plant performance. The efficacy of the proposed control scheme has been confirmed through rigorous simulations in terms of two specific tests – a) tracking error test and b) hysteresis curve area test. Results show an enhanced positioning precision of the manipulator with the proposed dither control than without it. Owing to its algorithmic simplicity, the proposed control genre can be extended to the parlance of other nano-scale applications.
condition monitoring of the induction motors has been widely used in the detection of faults. This paper delves into the various faults and study of conventional and innovative techniques for induction motor faults with an identification of future research areas.
precise position tracking through piezo actuated micro nano
manipulator. In our study it has been shown that the effect of
hysteresis can be mitigated by the proper application of a
suitably selected dither sequence. The objective of the paper is to compare the various types of dither viz, Sinusoidal, Gaussian,
Rayleigh and Rician, as to which gives the optimal system
performance in terms of two tests- tracking error and area under the hysteresis curve. This paper starts with the analysis of a piezoelectric actuator based on the Dahl model. An inverse Dahl model based feed-forward mechanism in conjunction with a feedback control is used for the study of the actuator’s
performance. Dither injection is applied at three different places in the system and accordingly three different schemes namely displacement dither, voltage dither and combined dither have been developed and compared. Based on the simulations, the best type of dither and its corresponding intensity for a given place of dither injection has been established. Results ascertain dither based control as a simple and an efficient algorithm capable of providing very accurate micro-nano positioning.
the context of its modern day implications in precision
engineering industry. However, this apparently indispensible
technique has its limitations imposed by the continuous
manifestation of non-linearitities like hysteresis and creep. This
work explores a relatively new control paradigm in the form of
dither to successfully neutralize hysteresis, in particular for a
Dahl Model based X-Y micro manipulator system working with
feed-forward control mechanism. The efficiency of different
dithers viz., Gaussian, Sinusoidal, Rician and Rayleigh have been
put to rigorous tests and the best dither has been established in terms of relative reduction of tracking error. It is observed that a combined displacement and voltage dither significantly improves system performance as compared to an undithered system.
every other field dealing with electrical power. These motors are simple, efficient, highly robust and rugged
thus offering a very high degree of reliability. But like any other machine, they are vulnerable to faults,
which if left unmonitored, might lead to catastrophic failure of the machine in the long run. On-line
condition monitoring of the induction motors has been widely used in the detection of faults. This paper
delves into the various faults and study of conventional and innovative techniques for induction motor
faults with an identification of future research areas.
micro/nanofactory, atomic force microscopy, scanning probe microscopy, wafer design, biological cell manipulation, and so forth. Motivated by the necessity to improve trajectory tracking in such applications, this paper addresses the problem of rate dependent hysteretic nonlinearity in piezoelectric actuators (PEA). The classical second order Dahl model for hysteresis encapsulation is introduced first, followed by the identification of parameters through particle swarm optimization. A novel inversion based feedforward mechanism in combination with a feedback compensator is proposed to achieve high-precision tracking wherein the paradoxical concept of noise as a performance enhancer is introduced in the realm of PZAs. Having observed that dither induced stochastic resonance in the presence of periodic forcing reduces tracking error, dither capability is further explored in conjunction with a novel output harmonics based adaptive control scheme.The proposed adaptive controller is then augmented with an internal
model control based approach to impart robustness against parametric variations and external disturbances.The proposed control law has been employed to track multifrequency signals with consistent compensation of rate dependent hysteresis of the PEA. The results indicate a greatly improved positioning accuracy along with considerable robustness achieved with the proposed integrated approach even for dual axis tracking applications.
performance. Dither based control is known to ameliorate
hysteresis in piezoelectric actuators. However, due to parametric variations and uncertainties, dither control alone cannot achieve the desired positional accuracy. In order to effectively implement any real-time control to alleviate the effects of nonlinearity, an adaptive mechanism is the utmost priority to update the control system. This paper explores the effects of hysteretic nonlinearity in a second order Dahl model based piezo-driven manipulator. The plant performance is known to improve with a suitable amount of injected noise. The concept of dither based control is cascaded with the conventional PID controller to bring out an innovative adaptive voltage control strategy. A dual axis piezo platform is taken into account for the controller design and validation. The performance of the controller is verified using certain tests. Results show an improved positioning accuracy of the manipulator with the proposed control scheme than without
it. The proposed control emerges as an effective control strategy to improve trajectory tracking accuracy.
efficient plant performance. The efficacy of the proposed control scheme has been confirmed through rigorous simulations in terms of two specific tests – a) tracking error test and b) hysteresis curve area test. Results show an enhanced positioning precision of the manipulator with the proposed dither control than without it. Owing to its algorithmic simplicity, the proposed control genre can be extended to the parlance of other nano-scale applications.
condition monitoring of the induction motors has been widely used in the detection of faults. This paper delves into the various faults and study of conventional and innovative techniques for induction motor faults with an identification of future research areas.
precise position tracking through piezo actuated micro nano
manipulator. In our study it has been shown that the effect of
hysteresis can be mitigated by the proper application of a
suitably selected dither sequence. The objective of the paper is to compare the various types of dither viz, Sinusoidal, Gaussian,
Rayleigh and Rician, as to which gives the optimal system
performance in terms of two tests- tracking error and area under the hysteresis curve. This paper starts with the analysis of a piezoelectric actuator based on the Dahl model. An inverse Dahl model based feed-forward mechanism in conjunction with a feedback control is used for the study of the actuator’s
performance. Dither injection is applied at three different places in the system and accordingly three different schemes namely displacement dither, voltage dither and combined dither have been developed and compared. Based on the simulations, the best type of dither and its corresponding intensity for a given place of dither injection has been established. Results ascertain dither based control as a simple and an efficient algorithm capable of providing very accurate micro-nano positioning.
the context of its modern day implications in precision
engineering industry. However, this apparently indispensible
technique has its limitations imposed by the continuous
manifestation of non-linearitities like hysteresis and creep. This
work explores a relatively new control paradigm in the form of
dither to successfully neutralize hysteresis, in particular for a
Dahl Model based X-Y micro manipulator system working with
feed-forward control mechanism. The efficiency of different
dithers viz., Gaussian, Sinusoidal, Rician and Rayleigh have been
put to rigorous tests and the best dither has been established in terms of relative reduction of tracking error. It is observed that a combined displacement and voltage dither significantly improves system performance as compared to an undithered system.