Position Control Of DC Motor Research Articles

On robust position control of DC motors by ∈-PID controller and its application to humanoid robot arms

In this paper, we propose a new ∈-PID controller for DC motors. We provide a systematic design steps of selecting the gains of the proposed ∈-PID controller. We also analytically show that the proposed controller provides robustness against system parameter uncertainty and reduces the effect of unknown load torque to the order of ∈. The benefit of our control approach is that the PID gains are tuned conveniently by adjusting a single ∈ gain-factor. An experiment of DC motor control with its application to humanoid robot arms demonstrates the practical aspect of the proposed control method.

Robust position control of linear brushless DC motor drive sytstem based on μ-synthesis

A robust position controller is proposed for the uncertainty rejection problem in a linear brushless DC motor (LBDCM) drive system. Friction and load variation are the main uncertainties in the LBDCM drive system; only viscous friction has been considered in previous work. Highly nonlinear friction in the system is measured and compensated by a radial basis function network. For solving the problem of load variation, three-controllers are proposed for different normalised payload conditions. Each has their own range of tolerable-load-variation; a mass estimator is developed to extend the tolerable load variation to the sum of three. In addition, mode-switching control is applied to achieve improved time-response. Both simulated and experimental results show that the proposed controller can suppress the influence of nonlinear friction and reduce the effect of large load variations; robust stability and robust performance are illustrated by corresponding μ-plots.

High-Speed Position Control of Linear DC Motor for Carrier with Fast Response Using Seek Algorithm and Neural Network

This paper presents the high-speed position control method of the linear DC motor (LDM) for a carrier using seek control, which considers the variation of the switching line according to the change of load mass. The proposed control method uses the artificial neural network (ANN) algorithm to consider the variation of the switching line for many load masses. Switching line and moving velocity for each load mass are obtained by the repetitive modification algorithm and learned by ANN for the neurocontroller. The experimental results show that the proposed method is very efficient in the position control of LDM for a carrier.

Position Control of a LBDCM Drive

In this paper, the dynamic model estimation and quantitative position control of a linear brushless DC motor (LBDCM) drive are studied. First, the inverter-fed LBDCM drive is established and its dynamic model is estimated from measurements. Then, according to the estimated model at nominal case, a two-degree-of-freedom controller (2DOFC) is designed to meet the prescribed tracking and load regulation position control responses. As the system parameter and operating condition changes occur, an output feedback linear model following controller (MFC) is added to reduce the effects of perturbations, and hence the performance degradation can be reduced. Finally, a ramp position command with suitable changing rate is generated to avoid the occurrence of velocity limitation, and thus the overshoot of position response due to large-step command change can be eliminated.

A Reduced Order Time-Delay Control for Highly Simplified Brushless DC Motor

A reduced order time-delay control is derived and applied to the position control of a brushless DC motor with a highly simplified hardware configuration: use of six-step commutation without current control unit. In addition, the closed-loop stability has been analyzed by using the singular perturbation method. Throughout experimental studies, it is observed that reduced order time delay control effectively compensates for parameter variations and non-linearities, which a conventional PID control cannot handle with adequate performances. This result shows that reduced order time-delay control enables an economical design without compromising performance. More importantly, the example establishes a case that: a good control method can compensate for the hardware deficiency in a given plant, and as a result it even enables a simpler design of plants at the design stage.

Asymptotically stable adaptive load torque observer for precision position control of BLDC motor

A new control method for the precision robust position control of a brushless DC (BLDC) motor using the asymptotically stable adaptive load torque observer is presented. A precision position control is obtained for the BLDC motor system approximately linearised using the field-orientation method. DC motors have been gradually replaced by the BLDC motor, since the industry applications require more powerful actuators in small sizes. Many of these motor systems have BLDC motors to obtain high power rates. On the other hand, the disadvantages are the high cost and more complex controller caused by the complex driving principle of BLDC motors, and the load torque disturbance is directly affected to a motor shaft. The application of the load torque observer using fixed gain has been published (Ko et al, 1993). However, the flux linkage is not exactly known for a load torque observer. There is a problem of uncertainty of obtaining very high precision position control. Therefore, a model reference adaptive observer was considered to overcome the problem of the unknown parameter and torque disturbance (Ko et al, 1994), but this is a case of BIBO stability. A new model reference adaptive observer is considered and stability analysis is carried out using the Lyapunov stability theorem. As a result, asymptotically stable observer gain can be obtained without affecting the overall system response. The load disturbance detected by the asymptotically stable adaptive observer is compensated by feed-forwarding the equivalent current having the fast response.

MRAC load torque observer for position control of a brushless DC motor

MRAC load torque observer for position control of a brushless DC motor

Position control of a brushless DC motor without velocity measurements

The paper presents a rotor position-velocity tracking controller for a brushless DC motor-load system without velocity measurement. An 'observed integrator backstepping' procedure and a nonlinear rotor velocity observer are utilised to design a nonlinear tracking controller which guarantees globally exponentially stable position-velocity tracking. The proposed controller is successfully implemented on a brushless DC motor-load system.

Robust digital position control of brushless DC motor with adaptive load torque observer

A new control method for the robust position control of a brushless DC (BLDC) motor using the adaptive load torque observer is presented. It is shown that the augmented state variable feedback can be applied to the BLDC motor system approximately linearised using the field-orientation method. To overcome the problem of an unknown parameter or a parameter variation such as a flux linkage, an adaptive mechanism is employed. As a result, the robustness can be obtained without affecting the overall system response. The load disturbance is detected by the adaptive 0-observer of an unknown and inaccessible input, and is compensated by feedforwarding the equivalent current having the fast response.

A robust digital position control of brushless DC motor with dead beat load torque observer

A method for the robust position control of brushless DC (BLDC) motors is presented. The linear quadratic controller plus load torque observer is used to obtain an approximately linearized robust BLDC motor system for an AC servo, using the field-orientation method. The gains are obtained systematically from a discrete state space analysis. The robustness is obtained without affecting the overall system response. The load disturbance is detected by a zero-observer of the unknown and inaccessible input, and is feedforward compensated without requiring noisy current information. The overall system is controlled using a microprocessor, and the performance of each control algorithm is compared with both the simulation and the experimental results for two types of machines, a BLDC motor and a brushless direct drive (BLDD) motor. >

Position and Speed Sensorless Control of Brush-Less DC Motor Based on an Adaptive Observer.

A permanent magnet synchronous motor can be controlled as a DC brushless motor, for which the position sensor is needed for detecting the rotor position. In this paper, the research on speed control system without position and speed sensors is reported, where the rotor position and speed of the motor are estimated by means of an adaptive observer. To make the state equations linear, two new state variables are introduced. Consequently, based on the Iinear control theory, an adaptive observer is designed by which the estimated speed and position are converged to real ones. The system is verified to be asymptotically stable. The operation of the system at zero speed and the effects of the mismatched parameters used in the observer are also discussed. Finally, the speed control of the system is implemented. The computer simulation and the experiments show that the system is valid.

Robust servo design with applications

An optimal multivariable proportional-integral (PI) controller with preassigned eigenspectrum is designed so that the system output would track constant reference inputs in spite of constant but unknown plant disturbances. A sequential strategy for modal servomechanism design is given for the above problem. In addition, since the proposed PI controller is of state feedback type, an observer capable of estimating the unmeasurable state variables in spite of the presence of unknown disturbances is introduced, thus resulting in a suboptimal overall system. The separation property for the overall servo/observer system is illustrated. The design strategy is successfully used for position control of a brushless DC motor, and in a regulator mode for controlling a headbox which is an integral part of the modern paper machines used in the pulp and paper industry. >

Position control of DC motors via variable structure systems control: a chattering alleviation approach

A novel chattering alleviation control (CAC) algorithm is proposed for variable structure systems (VSSs). Both analog and digital controllers using the theory of CAC are applied to the position control problem of a DC servomotor system. Comparisons of the CAC with other VSS control algorithms indicate that the chattering can be alleviated. Since the input of the CAC method contains only low-frequency components, it will not excite unmodeled high-frequency plant dynamics. >

Adaptive model following control with variable structure control system

Abstract The adaptive model following bang‐bang control (BB‐MFC) and variable‐structure model following control (VSS‐MFC) have the advantage of no tracking error. However, they are impractical in mechanical application. They will excite the mechanical resonance due to the high‐frequency switching of control signal. Therefore, we use the “modified VSS”. By theoretical analysis, simulations and experiments, the “modified, VSS” effectively modifies the control signal. There was no mechanical resonance in the experiments of DC motor position control.

Variable structure postition control

This paper describes the application of the variable structure control (VSC) concept for dc motor position control. The control scheme is derived, implemented, and tested in the laboratory where both digital and analog controllers have been used to control a representative servo system. The control-system schematics are given and sample results are shown for illustration. The VSC experiment should be of interest to educators and design engineers who wish to demonstrate and investigate sophisticated position-control methods and their applications. This experiment may also serve as a basis for further applications of VSC.

A Microprocessor-Based Current Controller for SCR-DC Motor Drives

A new current controller for a three-phase full-wave silicon controlled rectifier (SCR) bridge, supplying a separately excited armature-controlled dc motor driving an inertial load is developed. The controller operates in two modes, one applicable when the motor armature current is continuous, the other when it is discontinuous. The current controller is then used in speed or position control of a dc motor. The control algorithms are simple and may easily be implemented in real time on a microcomputer.