• Journal of the Semiconductor & Display Technology
• /
• v.11 no.3
• /
• pp.13-18
• /
• 2012

This paper presents a velocity disturbance estimation system for the stable fine seek control using a genetic algorithm. To estimate accurately the velocity disturbance in spite of the uncertainties of fine actuator, the system utilizes an objective function to minimize the differences of the frequency characteristics between the nominal velocity control loop and the extremal velocity control loops. The objective function is considered by applying a genetic algorithm and the velocity disturbance is estimated by the measurable velocity, the adjusted velocity controller, and the fine actuator model. The proposed velocity disturbance estimation system is applied to the fine seek control system of a DVD recording device and is evaluated through the experimental results.

• Journal of Institute of Control, Robotics and Systems
• /
• v.15 no.1
• /
• pp.82-88
• /
• 2009

The output of the encoder is a digital pulse, which is also easy to be connected to a digital controller. There are various angular velocity detecting methods of M, T, and M/T. Each of them has its own properties. There is a common limitation that the angular velocity detection period is strongly dependent on the destination velocity magnitude in case of ultimate low range. They have ultimately long detection period or cannot even detect angular velocity at near zero velocity. This paper proposes a zero velocity detectable sensor algorithm with the dual encoder system. The sensor algorithm is able to keep detection period moderately at near zero velocity and even detect zero velocity within nominal period. It is useful for detecting velocity in case of changing rotational direction at which there occurs zero velocity. In this paper, various experimental results are shown for the algorithm validity.

• ETRI Journal
• /
• v.37 no.2
• /
• pp.328-337
• /
• 2015

This paper applies acceleration/deceleration control-based velocity profiles to an infeed control algorithm for a cross-belt-type sorting system to improve the accuracy and performance of the system's infeed. The velocity profiles are of a trapezoidal shape and often have to be modified to ensure that parcels correctly synchronize with their intended carriers. Under the proposed method, an infeed line can handle up to 5,600 items/h, which indicates a 40% increase in performance in comparison with its existing handling rate of 4,000 items/h. This improvement in performance may lead to a reduction in the number of infeed lines required in a sorting system. The proposed infeed control algorithm is applied to a cross-belt-type sorting system (model name: SCS 1500) manufactured by Vanderlande Industries.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.34S no.11
• /
• pp.63-72
• /
• 1997

The design and implementation of a drive wheel position, orientation, and velocity feedback control algorithm for a differential-drive mobile robot is described here. A new concept, the most significant error, is introduced as the control design objective. Drive wheel position, orientation, and velocity feedback control directly minimize the most siginificant error by coordinating the motion of the two drive wheels. The drive wheel position, orientation, and velocity feedback control algorithm is analyzed and experiments are conducted to evaluate its performance. The experimental results are shown that drive wheel position, orientation and velocity feedback control algorithm yields substantially smaller position and orientation errors than those of conventional methods.

• Proceedings of the KSME Conference
• /
• 2000.04a
• /
• pp.487-492
• /
• 2000

Yaw moment control algorithm for improving stability of a vehicle in cornering is presented in this paper. A change of the yaw moment according to an increment in brake ship at each wheel is examined and reflected in the control algorithm. This control algorithm computes the target yaw velocity as the vehicle motion desired by the driver for directional stability control in cornering and it makes the actual yaw velocity follow the target one. The yaw moment control was achieved by brake slip control and simple brake slip control logic was introduced in this paper.

• Journal of Advanced Marine Engineering and Technology
• /
• v.17 no.5
• /
• pp.44-53
• /
• 1993

In this paper, we discuss on the control algorithm to make the wheeled inverse pendulum type mobile robot move in two dimensional plane. The robot considered in this paper has two independently driven wheels in same axel which suport and move it-self, and is assumed to have the fyro type sensor to know the inclination algle of the body and rotary encoders to know wheel's rotation angular velocity. The control algorithm is divided into three parts. The first part is for the posture and velocity control for forward-backward direction, the second is the steering control, and the last part is for the control of total system to track the given trajectory. We handle the running velocity control of the robot as part of the posture control to keep the balance because the posture relates deeply with the velocity and can be controlled by the velocities of the wheels. The control problem is analyzed as the tracking control, and the controller is realized with the state feedback and feed-forward of the reference velocity. Constructing the control system which contained one intergrator in forward path, we also realized the control system without observer for the estimation of the accumulated errors in the inclination angle of the body. To prevent the robot from being unstable state by sudden variation of the reference velocity when it starts and stops, or changes velocity, the reference velocity of which acceleration is slowly changing, is ordered to the robot. To control its steering, we give the different reference velocities for both wheels which are calculated from the desired angular velocity of the body. Finally, we presents the experimental results of the experimental robot Yamabico Kurara in which the proposed control algorithm had been implemented.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.17 no.2
• /
• pp.147-155
• /
• 2005

For a long road tunnel, a tunnel ventilation system may be used in order to reduce the pollution level below the required level. To control the tunnel pollution level, a closed loop control algorithm may be used. The cascade control algorithm, which composed of a jet fan control algorithm and an air velocity setpoint algorithm, was developed to regulate the CO level in a tunnel. The verification of control algorithms was carried out by dynamic models developed from real tunnel data sets. The simulation results showed that control algorithms developed for this study were effective to control the tunnel ventilation system.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.5
• /
• pp.505-511
• /
• 2011

In this paper, we have developed an automatic velocity control system of a small-sized commercial treadmill (belt length of 1.2 m and width of 0.5 m) which is widely used at home and health centers. The control objective is to automatically adjust the treadmill velocity so that the subject's position is maintained within the track when the subject walks at a variable velocity. The subject's position with respect to a reference point is measured by a low-cost sonar sensor located on the back of the subject. Based on an encoder sensor measurement at the treadmill motor, a state feedback control algorithm with Kalman filter was implemented to determine the velocity of the treadmill. In order to reduce the unnatural inertia force felt by the subject, a predefined acceleration limit was applied, which generated smooth velocity trajectories. The experimental results demonstrate the effectiveness of the proposed method in providing successful velocity changes in response to variable velocity walking without causing significant inertia force to the subject. In the pilot study with three subjects, users could change their walking velocity easily and naturally with small deviations during slow, medium, and fast walking. The proposed automatic velocity control algorithm can potentially be applied to any locomotion interface in an economical way without having to use sophisticated and expensive sensors and larger treadmills.

• International Journal of Control, Automation, and Systems
• /
• v.6 no.3
• /
• pp.386-393
• /
• 2008

A position control method for interpolating aspherical grinding and polishing tool path was reviewed and experimented in a nano precision machine. The position-base algorithm was reformed from the time-base algorithm, proposed in the previous study. The characteristics of the algorithm were in the velocity control loop with position feedback. The aspherical surface was divided by an interval at which each velocity and acceleration were calculated. The theoretical velocity was corrected by position error during processing. In the experiment, a machine was constructed and nano-scale linear encoders were installed at each axis. Relation between process parameters and the variation of position error was monitored and discussed. The best result from optimized parameters showed that the accuracy was 150nm and improved from the previous report.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.11
• /
• pp.1035-1043
• /
• 2004

For a long road tunnel, a tunnel ventilation system may be used in order to reduce the pollution level below the required level. To control the tunnel pollution level, a closed loop control algorithm may be used. The feedforward prediction algorithm and the cascade control algorithm were developed to regulate the CO level in a tunnel. The feedforward prediction algorithm composed of the traffic estimation algorithm and the CO density prediction algorithm, and the cascade control algorithm composed of the jet fan control algorithm and the air velocity setpoint algorithm. The verification of control algorithms was carried out by dynamic models developed from the actual tunnel data. The simulation results showed that control algorithms developed for this study were effective for the control of the tunnel ventilation system.