• International Journal of Precision Engineering and Manufacturing
• /
• v.4 no.5
• /
• pp.5-14
• /
• 2003

Tracking control schemes on the precise mechanical system in presence of nonlinear dynamic friction is proposed. A nonlinear dynamic friction is regarded as the bristle friction model to compensate fer effects of friction. The conventional SMC method often shows poor tracking performance in high-precision position tracking application since it cannot completely compensate for the friction effect below a certain precision level. Thus to improve the precise position tracking performance, we propose the SMC method combined with the disturbance observer having tunable transient performance. Then this control scheme has the high precise tracking peformance as well as a good transient response when it is compared with the conventional SMC method and the similar types of observers, The experiment on the XY ball-screw drive system with the nonlinear dynamic friction confirms the feasibility of the proposed control scheme.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.11
• /
• pp.1423-1433
• /
• 2018

Recently, a permanent magnet synchronous motor of middle and small-capacity has high torque, high precision control and acceleration / deceleration characteristics. But existing control has several problems that include unpredictable disturbances and parameter changes in the high accuracy and rigidity control industry or nonlinear dynamic characteristics not considered in the driving part. In addition, in the drive method for the control of low-vibration and high-precision, the process of connecting the permanent magnet synchronous motor and the load may cause the response characteristic of the system to become very unstable, to cause vibration, and to overload the system. In order to solve these problems, various studies such as adaptive control, optimal control, robust control and artificial neural network have been actively conducted. In this paper, an incremental encoder of the permanent magnet synchronous motor is used to detect the position of the rotor. And the position of the detected rotor is used for low vibration and high precision position control. As the controller, we propose augmented state feedback control with a speed observer and first order deadbeat disturbance observer. The augmented state feedback controller performs control that the position of the rotor reaches the reference position quickly and precisely. The addition of the speed observer to this augmented state feedback controller compensates for the drop in speed response characteristics by using the previously calculated speed value for the control. The first order deadbeat disturbance observer performs control to reduce the vibration of the motor by compensating for the vibrating component or disturbance that the mechanism has. Since the deadbeat disturbance observer has a characteristic of being vulnerable to noise, it is supplemented by moving average filter method to reduce the influence of the noise. Thus, the new controller with the first order deadbeat disturbance observer can perform more robustness and precise the position control for the influence of large inertial load and natural frequency. The simulation stability and efficiency has been obtained through C language and Matlab Simulink. In addition, the experiment of actual 2.5[kW] permanent magnet synchronous motor was verified.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.10a
• /
• pp.301-305
• /
• 2001

Conventionally, robot control algorithms are divided into two stages, namely, path or trajectory planning and path tracking(or path control). This division has been adopted mainly as a means of alleviating difficulties in dealing with complex, complex, coupled manipulator dynamics. The minimum-time manipulator control problem is solved for the case when the path is specified and the actuator torque limitations are known. In path planning, DP is applied to applied to find the shortest path form initial position to final position with the assumptions that there is no obstacle and that each path is straight line. In path control, the phase plane technique is applied to the minimum-time control with the assumptions that the bound on each actuator torque is a function of joint position and velocity or constant. This algorithm can be used for any manipulator that has rigid link, known dynamics equations of motion, and joint angles that can be determined at a given position on the path.

• Journal of Institute of Control, Robotics and Systems
• /
• v.9 no.1
• /
• pp.22-29
• /
• 2003

A piezoelectric actuator yields hysteresis effect due to its composed ferroelectric. Hysteresis nonlinearty is neglected when a piezoelectric actuator moves with short stroke. However when it moves with long stroke and high frequency, the hysteresis nonlinearty can not be neglected. The hysteresis nonlinearty of piezoelectric actuator degrades the control performance in precision position control. In this paper, in order to improve the control performance of piezoelectric actuator, an inverse modeling scheme is proposed to compensate the hysteresis nonlinearty. And feedforward - feedback controller is proposed to give a good tracking performance. The Feedforward controller is an inverse hysteresis model, base on neural network and the feedback control is implemented with PID control. To show the feasibility of the proposed controller and hysteresis modeling, some experiments have been carried out. It is concluded that the proposed control scheme gives good tracking performance.

• Transactions on Control, Automation and Systems Engineering
• /
• v.4 no.4
• /
• pp.296-304
• /
• 2002

A position tracking control schemes on the precise mechanical system in presence of nonlinear dynamic friction is proposed. A nonlinear dynamic friction is regarded as the bristle friction model to compensate effects of friction. The conventional sliding mode controller often has been used as a non-model-based friction controller, but it has a poor tracking performance in high-precision position tracking application since it completely cannot compensate the friction effect below a certain precision level. Thus to improve the precise position tracking performance, we propose the sliding mode control method combined with the friction-model-based observer having tunable structure of the transient response. Then this control scheme has a good transient response as well as the high precise tracking performance compared with the conventional sliding mode control without observer and the control system with similar type of observer. The experiments on the bali-screw drive table with the nonlinear dynamic friction show the feasibility of the proposed control scheme.

• International Journal of Precision Engineering and Manufacturing
• /
• v.5 no.4
• /
• pp.14-20
• /
• 2004

In this work, a new control methodology to achieve accurate position control of an AC servo motor subjected to external disturbance is proposed. Unlike conventional sliding mode controller which requires a prior knowledge of the upper bound of external disturbance, the proposed technique, called sliding mode controller with disturbance estimator (SMCDE), can offer robust control performances without a prior knowledge of the disturbance bound. The SMCDE is featured by an integrated average value of the imposed disturbance over a certain sampling period. By doing this, undesirable chattering phenomenon in the estimation process can be effectively alleviated. The benefits of the proposed control methodology are empirically demonstrated on AC servo motor and control responses are evaluated through a comparative work between the proposed and conventional control schemes.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.3 s.96
• /
• pp.109-115
• /
• 1999

This paper presents a stabilization control designed to improve position stabilization performance of a position servo-system(turret) mounted on a manuvering platform(vehicle). In the consideration of the motion of the platform, a dynamic model of the stabilization system is derived and shows the viscous and stick-slip friction torques are the major source of stabilization errors. An extended generalized minimum variance control which consists of a feedforward disturbance compensation as well as a pole placement feedback control is suggested to reduce the stabilization errors caused from the friction disturbances. This modeling and control are applied to a small experimental set-up and the experimental results confirm the accuracy of the model and the effectiveness of the suggested control.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.12
• /
• pp.48-58
• /
• 2010

In this study, position tracking and force reflection control of a master-slave manipulator which will be used for handling objects contaminated by radioactivity has been addressed. Since available measurements concerning on dynamic motion of the master-slave manipulator are restricted, a simple constrained control structure was suggested. In the consideration of the uncertain dynamic behaviors of the slave manipulator which is dependent upon mass and shape of work pieces grasped and dynamic properties of the environment contacted, a simple structured sliding mode control was suggested to guarantee robustness with respect to parameter uncertainties and external disturbances. The proposed control was applied to a 1-DOF master-slave link system. The control performances were verified along with some computer simulation results.

• Proceedings of the KIEE Conference
• /
• 2005.04a
• /
• pp.43-45
• /
• 2005

A High precision position control technique is used in many kind of industry areas. Especially this is to be one of the important parts in the development of precision machines. To get high precision and long range, dual servo voice coil motor(VCM) has been designed and implemented. In this paper, as a simulation and experimental result, the developed dual servo VCM shows the applicable possibility for precision machine system.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.05a
• /
• pp.153-154
• /
• 2006

Development of sorting machine for photo diode and its control system is addressed. The sorting machine for optical communication device requires high positional precision because the alignment is one of the most important point in the sorting process. This sorting method describes how to detect the target chip's angle and position from the wafer. The machine vision system is used for the feedback control. This sorting machine is implemented by motion controller, machine vision and various solenoid valve and is interfaced with RS-232c, GPIB and PCI communication. This system gets the position accuracy within $1{\mu}m$ with our experiments.