Variable Reluctance Stepper Motor Research Articles

Controlling the half-step mode operation of the variable reluctance stepper motor by using Mamdani type of fuzzy logic controller

<span lang="EN-US">This paper proposed the step angle controlling of the half-step mode operation of the variable reluctance stepper motor (VRSM) by using Mamdani type of fuzzy logic controller (FLC). The MATLAB program was used to achieve the approach. The VRSM that was used in this paper has six stator poles and four rotor poles. The VRSM has three phases that represent the input variables and the step angle represents the output variable in the FLC in MATLAB. Membership functions were created for the input and output variables. The rules of the FLC were built in MATLAB. The theoretical step angles results of the VRSM were obtained by using mathematically equation while the practical results were obtained by using MATLAB. The obtained results are closer to the actual results depending on the comparison between the theoretical and practical readings. These results were written in table and were plotted in figure.</span>

Designing driving and control circuits of four-phase variable reluctance stepper motor using fuzzy logic control

Precise positioning and repeatability of movement for stepper motors require designing a robust control system. To achieve that, an analytical model of a four-phase variable reluctance stepper motor is presented. A proposed open-loop driving circuit is designed to control the motion of a variable reluctance stepper motor. The driving circuit has an ability to drive the motor into two-step angles, i.e. a full step (15^{circ }) and a half step (7.5^{circ }). The direction of movement can be either into clockwise or counterclockwise direction. The operation of the variable reluctance stepper motor in an open-loop control circuit has demonstrated disadvantages of an oscillation and a relatively high settling time. Therefore, a closed-loop control circuit has been introduced using fuzzy logic control to overcome the oscillation problem and to obtain on a precise positioning within a reasonable settling time. The fuzzy logic control is used to improve and enhance the behaviour of the step position response based on oscillatory response and hence to reduce the overshoot significantly. The comparisons between the open- and closed-loop circuits are presented to demonstrate the disparity between both control circuits. The simulation results of the open-loop and the closed-loop circuits show that the time responses have been improved using different loads conditions. The simulation experiments are conducted and investigated using MATLAB–SIMULINK software package.

Application Research of Stepper Motor Control with TMS320F2812

This paper introduces how to realize the stepper motor control based on digital signal processor TMS320F2812. The paper introduces two control methods of the variable reluctance stepper motor based on the TMS320F2812’s general purpose input/output (GPIO) and event manager (EV) respectively. Also the control principle of the hybrid stepper motor based on the space vector PWM (SVPWM) is discussed. How to configure the peripheral registers of the comparison unit and the PWM generating circuit in the event manager of TMS320F2812 to generates the SVPWM signal is given out.

Effect of minimum energy control on steel loss in VR stepper motor

Abstract This research presents a 3D FE method for the simulation of the variable reluctance stepper motor dynamics. The proposed model is used to obtain the optimal minimum energy control law that minimizes the energy injected by the controller. The method is based on the strong coupling of field - circuit equations and extended to eddy current, motion and nonlinearity problem. The linearization technique for the coupled problem is presented. Also the lamination of the motor core is considered. In the paper the open - loop control problem is analyzed. The proposed model is validated by the comparison with measurements. Next, to demonstrate the effectiveness of the proposed optimal minimum energy control method is applied. In both cases, the examination of the variable reluctance stepper motor dynamics and the steel loss in the core is presented and compared

EFFECTS OF EARLY SWITCHING OFF ANGLE ON STEPPING MO PERFORMANCE

This paper analyzes the performance of the three-phase variable reluctance stepper motor (VRSM) in case of single-phase excitation mode. Equations of phase self inductances, instantaneous phase and supply currents, phase and total torques, total input and output power as well as the efficiency are all deduced for any rotor position. Also the paper analyzes the effect of the early switching OFF of the supply on the performance characteristics of the motor. To avoid negative torque production, the switching OFF of the phase excitation should be controlled. In order to guarantee removal of the phase current before the phase inductance start to decrease, the instant of the switching OFF would take place before that of the teeth alignment

Step response optimization method of switched reluctance motor

PurposeThe purpose of this paper is to present a method of modeling the variable reluctance stepper motor using the time‐stepping finite element technique. The proposed model is used to minimize the step response overshoots considering the stator and rotor tooth geometry.Design/methodology/approachA strongly coupled field‐circuit model considering magnetic nonlinearity of the stepper motor is presented. As the main contribution, the Nelder‐Mead method of the motor geometry optimization that minimize the step response overshoots and positioning error is proposed.FindingsThe proposed method can be applied to obtain the optimal tooth/pole geometry of the stepper motor which is efficient to perform the possibly accurate positioning.Originality/valueThe paper examines the application of the presented optimization method to minimize the positioning error of the four‐phased variable reluctance stepper motor.

Modeling and optimal control of variable reluctance stepper motor

PurposeThe purpose of this paper is to present a method of modeling the variable reluctance stepper motor using the time‐stepping finite element technique. The proposed model is used to obtain the optimal control law for the input circuit solving the linear‐quadratic problem.Design/methodology/approachA strongly coupled field‐circuit model of the stepper motor is presented. Also, the method of the optimal control that minimizes the power loss in the motor windings is proposed.FindingsThe proposed optimal control method can be applied to the electrical machines connected to the electronic converters. Calculated control signals may be used to obtain the optimal waveforms of the input voltages at each phase of the analyzed machine.Originality/valueThe paper examines the application of the presented control method to minimize the power loss in the stator windings of the four‐phased variable reluctance stepper motor.

Sequence Generator To Derive 8-Phase Variable Reluctance Stepper Motor

Literature survey indicates that the design of sequence generator is considered for a few number of control sequences of stepper motor. In our research a new circuit is built in a simple design for generation of all required sequences up to eight phases for Variable Reluctance (V.R.) stepper motor .This circuit must be followed by a power drive circuit to achieve the power requirement of the stepper motor. In case of getting a certain sequence , these data must be given to the system ; number of phases, number of 1st energized phases, type of sequence (full step or half step mode) and finally the direction of rotation, hence the system in response will generate the required sequence. Some papers previously used SSI & MSI circuits to build the sequence generator ,but in this paper an LSI (EPROM) circuit as well as SSI & MSI circuits are used to get minimal design with less components. The paper includes a brief description of the fundamentals of sequences controlling the stepper motor, the detailed proposed circuit description and samples of experimental results with an appendix illustrating a complete map of the EPROM which is used to store all required sequences.

A bistable electromagnetically actuated rotary gate microvalve

Two types of rotary gate microvalves are developed for flow modulation in microfluidic systems. These microvalves have been tested for an open flow rate of up to 100 sccm and operate under a differential pressure of 6 psig with flow modulation of up to 100. The microvalve consists of a suspended gate that rotates in the plane of the chip to regulate flow through the orifice. The gate is suspended by a novel fully compliant in-plane rotary bistable micromechanism (IPRBM) that advantageously constrains the gate in all degrees of freedom except for in-plane rotational motion. Multiple inlet/outlet orifices provide flexibility of operating the microvalve in three different flow configurations. The rotary gate microvalve is switched with an external electromagnetic actuator. The suspended gate is made of a soft magnetic material and its electromagnetic actuation is based on the operating principle of a variable-reluctance stepper motor.

Mechanism controller system for the optical spectroscopic and infrared remote imaging system instrument on board the Rosetta space mission

The optical, spectroscopic infrared remote imaging system (OSIRIS) is an instrument carried on board the European Space Agency spacecraft Rosetta that will be launched in January 2003 to study in situ the comet Wirtanen. The electronic design of the mechanism controller board (MCB) system of the two OSIRIS optical cameras, the narrow angle camera, and the wide angle camera, is described here. The system is comprised of two boards mounted on an aluminum frame as part of an electronics box that contains the power supply and the digital processor unit of the instrument. The mechanisms controlled by the MCB for each camera are the front door assembly and a filter wheel assembly. The front door assembly for each camera is driven by a four phase, permanent magnet stepper motor. Each filter wheel assembly consists of two, eight filter wheels. Each wheel is driven by a four phase, variable reluctance stepper motor. Each motor, for all the assemblies, also contains a redundant set of four stator phase windings that can be energized separately or in parallel with the main windings. All stepper motors are driven in both directions using the full step unipolar mode of operation. The MCB also performs general housekeeping data acquisition of the OSIRIS instrument, i.e., mechanism position encoders and temperature measurements. The electronic design application used is quite new due to use of a field programmable gate array electronic devices that avoid the use of the now traditional system controlled by microcontrollers and software. Electrical tests of the engineering model have been performed successfully and the system is ready for space qualification after environmental testing. This system may be of interest to institutions involved in future space experiments with similar needs for mechanisms control.

Robust adaptive control of variable reluctance stepper motors

Robust adaptive nonlinear control of variable reluctance motors is considered. Utilizing a model for the motor that incorporates magnetic saturation, an adaptive controller is designed for the plant that is robust to parametric and dynamic uncertainties in the entire electromechanical system. A robust torque profile is first designed for the motor. Thereafter, a commutation strategy is applied to define desired currents that would produce the desired torque signals. The desired currents then become the tracking objective for the electrical subsystem. Voltage level control inputs are designed using backstepping and the robust control design methodology to track the desired currents. The overall stability of the system is shown using Lyapunov techniques. The tracking error is shown to be globally uniformly bounded. The control design is shown to be applicable to other motor models wherein the flux linkage is modeled as separable products of functions of the rotor position and winding currents. Simulation results are illustrated to show the performance of the controller.

Multiple reference frame analysis of a multistack: variable-reluctance stepper motor

A multistack variable-reluctance stepper motor is analyzed using the concept of multiple reference frames. The average-value model developed is shown to approximately predict steady-state and dynamic operation of this device. Moreover, the state variables of this model are constant in the steady state. Therefore, the differential equations which describe this model can be linearized whereupon an eigenvalue analysis can be used to investigate dynamic instabilities. It is shown that this approach can be used to approximately predict the occurrence of parametric instability which heretofore has not been achieved using an eigenvalue analysis. The average-value model established in this paper should serve as a unique tool to aid in the design of the machine as well as the controls associated with the electronic drive system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Analysis of steady-state operation of a multistack variable-reluctance stepper motor using qd0 variables

An approximate method of calculating the steady-state characteristics of a multistack, variable-reluctance stepper motor operating in the continuous speed mode is developed. The mathematical model of the motor is set forth, and the unipolar inverter drive of interest is discussed. The differential equation which governs the flux linkage is then solved explicitly using numerical integration to evaluate the flux linkage waveform. As an alternative to the direct solution, the Floquet transformation is used to obtain a time-invariant differential equation. The qd0-variables are used with the reference frame fixed in the rotor. This approach provides a means of accurately accounting for the harmonic components of the current. The method is shown to be more accurate than existing approximate methods, with a marked computational advantage over exact methods. >

Development of a spherical stepper wrist motor

This paper presents the design concept of a new spherical stepper robotic wrist motor capable of three degrees of freedom (DOF) motion in a single joint. The spherical wrist motor has significant potential applications where the demands on wrist torque and workspace are low but high speed manipulation of end-effector orientation is required continuously in all directions. Typical applications are plasma and laser cutting and micro-assembly. The spherical motor is developed on the basis of the principle of variable reluctance stepper motors. This paper highlights the fundamental differences between the operation of a three DOF spherical motor and that of the conventional stepper motor. The establishment of a theoretic basis for design, prototype development and performance prediction is sought. In particular, an analysis of torque prediction is discussed along with the presentation of kinematic and dynamic relationships. A hybrid digital/analog laboratory prototype control circuitry has been developed to demonstrate proof of concept feasibility and to assist in achieving an optimum design.

System control for a printwheel typewriter

This paper presents the design goals and architecture of the IBM ™WHEELWRITER typewriters. Some of the development efforts and resulting technical innovations, such as a unique print hammer design which minimizes sensitivities to current variations, are discussed. Included is a discussion of a variable-reluctance stepper motor driver that has selectable damping. A novel scheme for initializing the printwheel and escapement motors is given; this includes sensing the font weight. The electronic architecture of the typewriter and the design of a simplified algorithm to handle the many different keyboards that can be attached to the machine with a minimum amount of data storage are explained.

Optimal control of reluctance devices

The single-step optimal control of a variable-reluctance stepper motor is presented. The optimal policy is shown to be bang-bang, with current drive control, for an established nonlinear model with the torque proportional to the square of the current. The analytic result is confirmed by extensive computations of the actual optimal strategy. The formulation used retains the benefits of the open-loop control of the motor. The responses obtained are compared to the step response and are shown to exhibit substantial improvements. The general form of the control equally applies to machines, such as the reluctance motor, with similar models.