EPE Association: EPE 1997 – 71: Dialogue Session DS6a: SERVO DRIVES AND ACTUATORS

EPE 1997 – 71: Dialogue Session DS6a: SERVO DRIVES AND ACTUATORS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 71: Dialogue Session DS6a: SERVO DRIVES AND ACTUATORS

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   CURRENT CONTROL AND MAGNET CONFIGURATIONS FOR HIGH TORQUE TO CURRENT RATIO IN SURFACE MOUNTED PERMANENT MAGNET SYNCHRONOUS MOTORS
By K. Shinohara; Y. Mieno [View]
[Download]

Abstract: This paper discribes a method to obtain a high torque to current ratio by providing a new magnet configuration and to eliminate the pulsation of the output torque by the current control in the surface mounted permanent magnet (PM) synchronous motors. Although the output torque has been increased, the pulsation of the output torque has also been increased due to the distorted eletro motive force (EMF). To eliminate the pulsation torque, the current control method is proposed in this paper.

   HIGH PERFORMANCE VECTOR POSITION CONTROL OF A HELICAL RELUCTANCE MOTOR FOR AN ULTRA PRECISION LATHE
By S. Brückl [View]
[Download]

Abstract: For the Helical Reluctance Motor (HRM), which is a linear direct drive for long distance motions with a positioning accuracy in the submicrometer range, a model of the motor with a non-laminated and a laminated rotor has been derived and validated by numerous experiments. A field oriented digital current control both in the stator and rotor fixed coordinate frame have been designed and implemented on a DSP system achieving an equivalent time constant of 100 ps. A superimposed state feedback and cascaded position control have been investigated. The HRM has been applied as a feed drive in an ultra precision lathe. An equivalent time constant of 12 ms for the closed loop position control and a dynamic stiffnes of 18 N/um have been achieved.

   A DSP based Robust Optimal Servo Motor controller
By P. Kettle; A. Murray; A. Holohan [View]
[Download]

Abstract: This paper presents by example a design strategy based on linear quadratic gaussian controllers with loop transfer recovery (LQG / LTR). The design strategy presented is an integrated design synthesis procedure which is conducive to educated trade-off management. The controller design specification is expressed in terms of loop shaping bounds for load dynamic and model uncertainties, command response times and disturbance response times. The design philosophy is initially to satisfy the stability constraints subject to the model variation specification and then to satisfy the time domain design specifications. The LQG / LTR controller is synthesized in discrete time, the resulting design is a Robust-Optimal design.

   A LEARNING-BASED SPEED CONTROL OF SERVOMOTORS WITH ITS APPLICATION TO VIDEO-CASSETTE-RECORDER
By Young-Hoon Kim; In-Joong Ha; Jeo,ng-Tae Kim; Goan-Soo Seong [View]
[Download]

Abstract: This paper describes a learning control method which gives a low-cost solution to precision speed regulation problem for servomotors in the presence of unknown and unstructured disturbance torque. The disturbance torque under consideration includes both the external load torque and the pulsating torque. To show the generality of our work, theoretical analysis on the proposed method is given. Furthermore, the practical significance of our work is demonstrated through some experiments using a commercial home-use VCR.

   COMPARATIVE ANALYSIS OF DOUBLY-SALIENT RELUCTANCE AND PERMANENT MAGNET ACTUATORS
By M. M. Radulescu; C. Martis; K. Biro [View]
[Download]

Abstract: Both doubly-salient vanriable reluctance (DSVR) and permanent-magnet (DSPM) actuators are the focus of intensive research efforts during the past decade, and their torque production, design features and control characteristics have been well explored. This paper deals with a comparative study of doubly-salient variable reluctance (DSVR) and permanent-magnet (DSPM) actuators based on the magnetic flux distribution and equivalent circuit for static performance prediction.

   A NOVEL ELECTRONICALLY-OPERATED, LINEAR, VARIABLE-RELUCTANCE, ACTUATOR
By M. York; J. M. Stephenson; A. Hughes [View]
[Download]

Abstract: This paper describes a novel design for a powerful linear actuator which harnesses the highly unstable, normal-force of magnetic attraction to produce linear motion via a ratchet mechanism. The ratchet permits bi-directional operation when activated and prevents motion when the actuator is not activated. The operational principles and results from the prototype are presented.

   TRACKING CONTROL OF A TWO DEGREES OF FREEDOM ROBOT USING DISTURBANCE OBSERVER
By Stefan Dumbrava [View]
[Download]

Abstract: The robot system represents a class of non-linear, time-varying multiinput, multioutput dynamic system for which different control methods have been proposed. The difficulty of model based referenced control methods arises in the calculus of robot model due to parameter uncertainties. A method to determine the external torques using a disturbance observer is proposed. The input signals of the disturbance observer are: the actuating motor current and angular velocity, or position. The estimated disturbance obtained from the observer system is further used in a feedback control structure for disturbance compensation. In order to obtain good tracking properties, a predictive speed controller and a position controller are considered separately. The performances of the system, in the case of a two degrees of freedom robot actuated with de motors, are presented.

   SWITCHING FLUX PERMANENT MAGNET POLYPHASED SYNCHRONOUS MACHINES
By Emmanuel Hoang; Abdel Hamid Ben Ahmed; Jean Lucidarme [View]
[Download]

Abstract: This paper presents original structures if a permanent magnet synchronous polyphased machine with concentrated flux based on the switching flux principle. These machines are characterized Fry an association if elementary cells. The armature and the inductor are both located in the same part. The rotor is passive and has an important salienqy. From the elementary cell, the authors describe several structures. Computation results are then presented To make comparisons, all the machines have the same size. Computation has been done using a sinusoidal wave current having a density of 5 A/mm² and ferrite permanent magnets. The first machine is characterized by a same tooth pitch on rotor and stator. In this case, the massic torque and stress shear are respectively 1.7 Nm/kg and 1.18 N/cm². In the second one, the tooth pitch on stator and rotor are different. The massic torque and stress shear are respectively 1.97 Nm/kg and 1.37 N/cm². A new PM arrangement is proposed. The performances of this new configuration are improved. The massic torque and stress shear are respectively 3.62 Nm/kg and 3 N/cm². The developed study on this machine has not only shown interesting performances but a possible working with constant power, having a theoretically infinite range of speed.

   Optimized control on a two axis-robot by means of Evolution Strategies
By R. Richter; W. Hofmann [View]
[Download]

Abstract: The paper will focus on modem control techniques applied on a two axis robot with synchronous servo drives. Based on an experimental modeling different liner and nonlinear controllers are designed and implemented. The design by optimization was done by Evolution Strategies. These strategies had been also used for an online tuning of controller parameter. The implementation runs on a Pentium PC with IO-board and on a 80C166 micro controller board with a DSP extension (ADSP 2111).

   Some applications of the ultrasonic microactuators in robotic miniaturization
By Mircea Ignat; Gheorghe Amza [View]
[Download]

Abstract: Some theoretical and experimental aspects about a piezoceramic "muscle" structure and eye electromechanical systems with applications in micro robots are presented. The first experiments are described.

   INTELLIGENT MOTION: THE NEW CHALLENGE FOR ELECTRICAL DRIVES
By A. Johnson; J. M. Pacas [View]
[Download]

Abstract: In the past the developments of electrical drives were focused on the consolidation of the control methods the integration of components and the reduction of cost. New aspects arise due to the fact that in many machines and processes it is possible to substitute mechanical components by installing alternative electronic solutions. The paper presents the requirements to be fulfilled by a modern intelligent drive in order to cope with the demands of this kind of applications.

   FIELD MAGNITUDE ADAPTATION IN INDUCTION MOTORS
By H. Rasmussen [View]
[Download]

Abstract: A method for model adaptation is described and convergence properties are given. The method is used for estimation of the magnetizing inductance by minimizing the squared prediction error of the steady state quadrature voltage of the motor model. Both simulations and laboratory experiments show a robust performance of the method.

   ON LINE IDENTIFICATION AND COMPENSATION OF FRICTION INFLUENCE OF FEED DRIVES OF MACHINE TOOLS
By Thomas Frenz; Dierk Schri:ider [View]
[Download]

Abstract: In this paper a method called Stable Local Neuro-Identification is used for on line identification of unknown slowly time variant nonlinearities. The objective is to compensate the influence of this nonlinearity at any time. The development of a special hardware for real time implementation of the identification algorithm is shown. An application example shows the on line identification of the friction characteristic of a feed drive of a machine tool and the immediate compensation of the friction influence.

EPE 1997 – 71: Dialogue Session DS6a: SERVO DRIVES AND ACTUATORS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1997 - Conference > EPE 1997 – 71: Dialogue Session DS6a: SERVO DRIVES AND ACTUATORS
	[return to parent folder]

	CURRENT CONTROL AND MAGNET CONFIGURATIONS FOR HIGH TORQUE TO CURRENT RATIO IN SURFACE MOUNTED PERMANENT MAGNET SYNCHRONOUS MOTORS By K. Shinohara; Y. Mieno	[View] [Download]
Abstract: This paper discribes a method to obtain a high torque to current ratio by providing a new magnet configuration and to eliminate the pulsation of the output torque by the current control in the surface mounted permanent magnet (PM) synchronous motors. Although the output torque has been increased, the pulsation of the output torque has also been increased due to the distorted eletro motive force (EMF). To eliminate the pulsation torque, the current control method is proposed in this paper.

	HIGH PERFORMANCE VECTOR POSITION CONTROL OF A HELICAL RELUCTANCE MOTOR FOR AN ULTRA PRECISION LATHE By S. Brückl	[View] [Download]
Abstract: For the Helical Reluctance Motor (HRM), which is a linear direct drive for long distance motions with a positioning accuracy in the submicrometer range, a model of the motor with a non-laminated and a laminated rotor has been derived and validated by numerous experiments. A field oriented digital current control both in the stator and rotor fixed coordinate frame have been designed and implemented on a DSP system achieving an equivalent time constant of 100 ps. A superimposed state feedback and cascaded position control have been investigated. The HRM has been applied as a feed drive in an ultra precision lathe. An equivalent time constant of 12 ms for the closed loop position control and a dynamic stiffnes of 18 N/um have been achieved.

	A DSP based Robust Optimal Servo Motor controller By P. Kettle; A. Murray; A. Holohan	[View] [Download]
Abstract: This paper presents by example a design strategy based on linear quadratic gaussian controllers with loop transfer recovery (LQG / LTR). The design strategy presented is an integrated design synthesis procedure which is conducive to educated trade-off management. The controller design specification is expressed in terms of loop shaping bounds for load dynamic and model uncertainties, command response times and disturbance response times. The design philosophy is initially to satisfy the stability constraints subject to the model variation specification and then to satisfy the time domain design specifications. The LQG / LTR controller is synthesized in discrete time, the resulting design is a Robust-Optimal design.

	A LEARNING-BASED SPEED CONTROL OF SERVOMOTORS WITH ITS APPLICATION TO VIDEO-CASSETTE-RECORDER By Young-Hoon Kim; In-Joong Ha; Jeo,ng-Tae Kim; Goan-Soo Seong	[View] [Download]
Abstract: This paper describes a learning control method which gives a low-cost solution to precision speed regulation problem for servomotors in the presence of unknown and unstructured disturbance torque. The disturbance torque under consideration includes both the external load torque and the pulsating torque. To show the generality of our work, theoretical analysis on the proposed method is given. Furthermore, the practical significance of our work is demonstrated through some experiments using a commercial home-use VCR.

	COMPARATIVE ANALYSIS OF DOUBLY-SALIENT RELUCTANCE AND PERMANENT MAGNET ACTUATORS By M. M. Radulescu; C. Martis; K. Biro	[View] [Download]
Abstract: Both doubly-salient vanriable reluctance (DSVR) and permanent-magnet (DSPM) actuators are the focus of intensive research efforts during the past decade, and their torque production, design features and control characteristics have been well explored. This paper deals with a comparative study of doubly-salient variable reluctance (DSVR) and permanent-magnet (DSPM) actuators based on the magnetic flux distribution and equivalent circuit for static performance prediction.

	A NOVEL ELECTRONICALLY-OPERATED, LINEAR, VARIABLE-RELUCTANCE, ACTUATOR By M. York; J. M. Stephenson; A. Hughes	[View] [Download]
Abstract: This paper describes a novel design for a powerful linear actuator which harnesses the highly unstable, normal-force of magnetic attraction to produce linear motion via a ratchet mechanism. The ratchet permits bi-directional operation when activated and prevents motion when the actuator is not activated. The operational principles and results from the prototype are presented.

	TRACKING CONTROL OF A TWO DEGREES OF FREEDOM ROBOT USING DISTURBANCE OBSERVER By Stefan Dumbrava	[View] [Download]
Abstract: The robot system represents a class of non-linear, time-varying multiinput, multioutput dynamic system for which different control methods have been proposed. The difficulty of model based referenced control methods arises in the calculus of robot model due to parameter uncertainties. A method to determine the external torques using a disturbance observer is proposed. The input signals of the disturbance observer are: the actuating motor current and angular velocity, or position. The estimated disturbance obtained from the observer system is further used in a feedback control structure for disturbance compensation. In order to obtain good tracking properties, a predictive speed controller and a position controller are considered separately. The performances of the system, in the case of a two degrees of freedom robot actuated with de motors, are presented.

	SWITCHING FLUX PERMANENT MAGNET POLYPHASED SYNCHRONOUS MACHINES By Emmanuel Hoang; Abdel Hamid Ben Ahmed; Jean Lucidarme	[View] [Download]
Abstract: This paper presents original structures if a permanent magnet synchronous polyphased machine with concentrated flux based on the switching flux principle. These machines are characterized Fry an association if elementary cells. The armature and the inductor are both located in the same part. The rotor is passive and has an important salienqy. From the elementary cell, the authors describe several structures. Computation results are then presented To make comparisons, all the machines have the same size. Computation has been done using a sinusoidal wave current having a density of 5 A/mm² and ferrite permanent magnets. The first machine is characterized by a same tooth pitch on rotor and stator. In this case, the massic torque and stress shear are respectively 1.7 Nm/kg and 1.18 N/cm². In the second one, the tooth pitch on stator and rotor are different. The massic torque and stress shear are respectively 1.97 Nm/kg and 1.37 N/cm². A new PM arrangement is proposed. The performances of this new configuration are improved. The massic torque and stress shear are respectively 3.62 Nm/kg and 3 N/cm². The developed study on this machine has not only shown interesting performances but a possible working with constant power, having a theoretically infinite range of speed.

	Optimized control on a two axis-robot by means of Evolution Strategies By R. Richter; W. Hofmann	[View] [Download]
Abstract: The paper will focus on modem control techniques applied on a two axis robot with synchronous servo drives. Based on an experimental modeling different liner and nonlinear controllers are designed and implemented. The design by optimization was done by Evolution Strategies. These strategies had been also used for an online tuning of controller parameter. The implementation runs on a Pentium PC with IO-board and on a 80C166 micro controller board with a DSP extension (ADSP 2111).

	Some applications of the ultrasonic microactuators in robotic miniaturization By Mircea Ignat; Gheorghe Amza	[View] [Download]
Abstract: Some theoretical and experimental aspects about a piezoceramic "muscle" structure and eye electromechanical systems with applications in micro robots are presented. The first experiments are described.

	INTELLIGENT MOTION: THE NEW CHALLENGE FOR ELECTRICAL DRIVES By A. Johnson; J. M. Pacas	[View] [Download]
Abstract: In the past the developments of electrical drives were focused on the consolidation of the control methods the integration of components and the reduction of cost. New aspects arise due to the fact that in many machines and processes it is possible to substitute mechanical components by installing alternative electronic solutions. The paper presents the requirements to be fulfilled by a modern intelligent drive in order to cope with the demands of this kind of applications.

	FIELD MAGNITUDE ADAPTATION IN INDUCTION MOTORS By H. Rasmussen	[View] [Download]
Abstract: A method for model adaptation is described and convergence properties are given. The method is used for estimation of the magnetizing inductance by minimizing the squared prediction error of the steady state quadrature voltage of the motor model. Both simulations and laboratory experiments show a robust performance of the method.

	ON LINE IDENTIFICATION AND COMPENSATION OF FRICTION INFLUENCE OF FEED DRIVES OF MACHINE TOOLS By Thomas Frenz; Dierk Schri:ider	[View] [Download]
Abstract: In this paper a method called Stable Local Neuro-Identification is used for on line identification of unknown slowly time variant nonlinearities. The objective is to compensate the influence of this nonlinearity at any time. The development of a special hardware for real time implementation of the identification algorithm is shown. An application example shows the on line identification of the friction characteristic of a feed drive of a machine tool and the immediate compensation of the friction influence.