• Journal of Power Electronics
• /
• v.7 no.2
• /
• pp.159-173
• /
• 2007

In this paper, an intelligent sliding-mode position controller (ISMC) for achieving favorable decoupling control and high precision position tracking performance of permanent-magnet synchronous motor (PMSM) servo drives is proposed. The intelligent position controller consists of a sliding-mode position controller (SMC) in the position feed-back loop in addition to an on-line trained fuzzy-neural-network model-following controller (FNNMFC) in the feedforward loop. The intelligent position controller combines the merits of the SMC with robust characteristics and the FNNMFC with on-line learning ability for periodic command tracking of a PMSM servo drive. The theoretical analyses of the sliding-mode position controller are described with a second order switching surface (PID) which is insensitive to parameter uncertainties and external load disturbances. To realize high dynamic performance in disturbance rejection and tracking characteristics, an on-line trained FNNMFC is proposed. The connective weights and membership functions of the FNNMFC are trained on-line according to the model-following error between the outputs of the reference model and the PMSM servo drive system. The FNNMFC generates an adaptive control signal which is added to the SMC output to attain robust model-following characteristics under different operating conditions regardless of parameter uncertainties and load disturbances. A computer simulation is developed to demonstrate the effectiveness of the proposed intelligent sliding mode position controller. The results confirm that the proposed ISMC grants robust performance and precise response to the reference model regardless of load disturbances and PMSM parameter uncertainties.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.10a
• /
• pp.286-290
• /
• 2001

This paper presents a full-digital low-level controller for a robotic material transfer system which has been developed for a computer-integrated manufacturing model plant. Compared to conventional analog or hybrid type controllers in current industrial environments, this controller system has some advantages such as strong noise-immunity, easy control algorithm implementation, etc The servo-controller consists of two modules, a position controller and a DC servo motor driver. The position controller operates position feedback routines by receiving position encoder data and sending control outputs to the driver. The position controller is implemented in a full-digital way using a recently introduced microcontroller. The DC servomotor driver controls speeds and torques. The driver consists of a micro-controller and insulated-gate-bipolar-transistors (IGBT). The micro-controller provides control signals, and the IGBT's amplifies the control signals and sends them to the motor.

• Proceedings of the KIEE Conference
• /
• 1999.07b
• /
• pp.583-585
• /
• 1999

This paper presents the controller of multiple DC motors using the network. This controller has been built with 16-bits one chip microprocessor (87C196CA) which includes the integrated CAN serial communication and position control for two motors. Since only one microprocessor is needed, the proposed controller is not only cost effective but also powerful. The system is composed of one main controller, trajectory planner, and the other sub controller, position controller. The main controller which has been built using Visual Basic programming on the Pentium PC, generates the trajectory and then transmits it to the sub controller. The trajectory transmitted from the PC will be processed by the sub controller. Two motors are controlled using the conventional position control, PID, to reach them the same target position but with different velocities at the same time. The communications between the main controller and sub controller is performed through the RS-232 or the CAN communication The CAN would be safer and faster than serial communication network since it has non-destructive bitwise arbitration specification. In this paper, we consider the CAN communications generally and then show the usefulness of the proposed controller by demonstrating position control of two DC motors.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.498-503
• /
• 2005

This paper is concerned with the implementation of adaptive positive position feedback controller using a digital signal processor and microcontroller The main advantage of the positive position feedback controller is that it can control a natural mode of interest by tuning the filter frequency of the positive position feedback controller to the natural frequency of the target mode. However, the positive position feedback controller loses its advantage when mistuned. In this paper, the fast fourier transform algorithm is implemented on the microcontroller whereas the positive position feedback controller is implemented on the digital signal processor. After calculating the frequency which affects the vibrations of structure most the result is transferred to the digital signal processor. The digital signal processor updates the information on the frequency to be controlled so that it can cope with both internal and external changes. The proposed scheme was installed and tested using a beam equipped with piezoceramic sensor and actuator. The experimental results show that the adaptive positive position feedback controller proposed in this paper can suppress vibrations even when the target structure undergoes structural change thus validating the approach.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.7
• /
• pp.115-121
• /
• 1996

Multi-axes driving system is more suitable for FMS(Flexible Manufacturing System) compared with a conventional single-azis driving system. It has some merits such as flexibility in operation, improvement of net working rate, maintenance free because of no gear train, etc. However, studies on position synchronous control for high precision in the multi-axes driving system are not enough. In this paper, a new method of position synchronous control is suggested in order to apply to the multi- axes driving system. The proposed method is structured very simply using speed and position controller based on PID control law. Especially, the position controller is designed to keep position error to minimize by controlling either speed of two motors. The effectiveness of the proposed method is successfully confirmed through several experiments.

• Journal of Power Electronics
• /
• v.9 no.1
• /
• pp.74-84
• /
• 2009

The design and implementation of a high performance PID (Proportional Integral & Differential) style controller with zero-phase error tracking property is considered in this article. Unlike a ball screw driven system, the controller in a direct drive system should provide a high level of tracking performance while avoiding the problems due to the absence of the gear system. The stiff mechanical element in a direct drive system allows high precise positioning capability, but relatively high tracking ability with minimal position error is required. In this work, a feasible position controller named 'Unified PID controller' is presented. It will be shown that the function of the closed position loop can be designed into unity gain system in continuous time domain to provide minimal position error. The focus of this work is in two areas. First, easy gain tunable PID position controller without speed control loop is designed in order to construct feasible high performance drive system. Second, a simple but powerful zero phase error tracking strategy using the pre-designed function of the main control loop is presented for minimal tracking error in all operating conditions. Experimental results with a s-curve based position pattern commonly used in industrial field demonstrate the feasibility and effective performance of the approach.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.2
• /
• pp.391-398
• /
• 2009

In this study, we introduce the design methodology of an optimized fuzzy cascade controller with the aid of hierarchical fair competition-based genetic algorithm(HFCGA) for ball & beam system. The ball & beam system consists of servo motor, beam and ball, and remains mutually connected in line in itself. The ball & beam system determines the position of ball through the control of a servo motor. The displacement change the position of ball leads to the change of the angle of the beam which determines the position angle of a servo motor. Consequently the displacement change of the position of the moving ball and its ensuing change of the angle of the beam results in the change of the position angle of a servo motor. We introduce the fuzzy cascade controller scheme which consists of the outer(1st) controller and the inner(2nd) controller as two cascaded fuzzy controllers, and auto-tune the control parameters(scaling factors) of each fuzzy controller using HFCGA. The inner controller controls the position of lever arm which corresponds to the position angle of a servo motor and the outer controller decides the set-point value of the inner controller. HFCGA is a kind of parallel genetic algorithms(PGAs), and helps alleviate the premature convergence being generated in conventional genetic algorithms (GAs). For a detailed comparative analysis from the viewpoint of the performance results and the design methodology, the proposed method for the ball & beam system which is realized by the fuzzy cascade controller based on HFCGA, is presented in comparison with the conventional PD cascade controller based on serial genetic algorithms.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11a
• /
• pp.310-313
• /
• 2005

This paper is concerned with the active vibration control of beam equipped with piezoceramic sensors and actuators. The single-input and single-output positive position feedback controller is considered as an active vibration controller for the beam. The proposed single-input and single-output positive position feedback controller can cope with many modes of interest by summing each positive position feedback controller designed for each mode. In this paper, theoretical formulation is first explained in detail. We discuss how to design the single-input and single-output positive position feedback controller for a target structure by considering Euler-Bemoulli beam. It is found that the theories developed in this study are capable of predicting the control system characteristics and its performance.

• Journal of Institute of Control, Robotics and Systems
• /
• v.10 no.4
• /
• pp.317-324
• /
• 2004

The ink jet printer media advance system is required to be exactly driven to the target position via tracking the reference velocity profile to obtain the high quality print image. A single gain PID controller is not sufficient to fulfill the control objectives, the exact velocity tracking and the accurate positioning, at the same time. A dual PID controller and its switching strategy are presented in this paper to achieve the control objectives. The media advance system is controlled by two separate PID controllers, one of which is for velocity control, and the other is for position control. A PID controller controls the velocity of the media advance system until it reaches the predetermined switching position. When the media advance system passes the predetermined position, the controller is switched to the other PID controller which is more profitable for exact positioning. The switching position is determined by the estimated stop distance. The simulation and experimental results are presented to show the validity and effectiveness of the proposed controller.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.5B no.2
• /
• pp.189-195
• /
• 2005

This paper presents a new velocity estimation strategy for a non-salient permanent magnet synchronous motor drive without high frequency signal injection or special PWM pattern. This approach is based on the d-axis current regulator output voltage of the drive system, which contains the rotor position error information. The rotor velocity can be estimated through a rotor position tracking PI controller that controls the position error at zero. For zero and low speed operation, the PI gain of the rotor position tracking controller has a variable structure according to the estimated rotor velocity. Then, at zero speed, the rotor position and velocity have sluggish dynamics because the varying gains are very low in this region. In order to boost the bandwidth of the PI controller during zero speed, the loop recovery technique is applied to the control system. The PI tuning formulas are also derived by analyzing this control system by frequency domain specifications such as phase margin and bandwidth assignment.