• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.3
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• pp.223-230
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• 2017

A low-cost BLDC motor with hall sensor is used to drive the position control of a facility security monitoring system in this paper. Low measurable frequency of the hall sensor signal in low-speed regions results in difficulty in obtaining accurate speed detection and position control. To improve system control performance, we propose a variable gain of position controller and stop mode control scheme according to the motor speed and error position with pre-set deceleration time. The proposed stop mode control scheme is activated around the stop position to forcibly move the BLDC motor to the stop position in low speed. In the proposed stop mode, the motor current is controlled by the actual speed with the reference rotating angle. The control performance of the proposed position control is verified through experiments at the actual rail guided facility security monitoring system.

• Journal of Biosystems Engineering
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• v.14 no.3
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• pp.168-180
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• 1989

This study was attempted to develop the electronic-hydraulic hitch control system for position control of tractor plow and investigate the control performance of the system through experiments. Experiments were carried out to investigate the responses of the system to the step and sinusoidal inputs in position control. The effects of control mode, hydraulic flow rate, reference deadband, and proportional constant on control performance of the system were investigated. The following conclusions were derived from the study; 1. For the position control system operated on on-off control mode, positions of implement were controlled within ${\pm}0.73^{\circ}{\sim}{\pm}1.46^{\circ}$ in rockshaft angle to the reference position when the hydraulic flow rates were 5~15 l/min. For the position control system operated on PWM control mode, positions of implement were controlled within ${\pm}0.73^{\circ}$ to the reference position regardless of hydraulic flow rates. It means that the implement could be positioned more accurately to the reference position on PWM control mode than on on-off control mode. 2. As results of the frequency responses of the position control systems, no clear difference in control performance between on-off control and PWM control modes was found. As the hydraulic flow rates increased, the corner frequencies of amplitude attenuation and phase-angle change increased. It means that the control performance of the system could be improved as the hydraulic flow rate increases.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.913-916
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• 1990

In this paper, attempts have been made to control AC synchronous servo motor used as actuators of joints of the FARA robot with high dynamic performance and precise positioning. The AC synchronous servo motors used in FARA robots have resolves as position sensors. Resolver to digital converters are used in order to obtain the information of rotor speed and position from resolver outputs. The proposed joint position control system consists of four speed controller and one position controller. Analog methods are used in the position controller, while digital methods are used in the position controller. For precise position control, PID control algorithm and interpolation functions are executed in two 16 bit microprocessors with sampling rate 2ms. Experimental results show that the proposed joint position control system can be effectively applied to industrial robots in order to obtain high dynamic performance and precise positioning. The proposed joint position control system is being used in the control of FARA robots of Samsung Electronics.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.85.1-85
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• 2002

In this paper, a control strategy of position and force is proposed based on a switching algorithm. The main focus is the control of position and force in the same direction. The switching algorithm based on a fuzzy algorithm determines the weighting value of force control. First, the force control is dominant. If the position gets closer to the desire position, the weighting value of force control is closer to zero. The proposed algorithm is shown to be satisfactory to position and force control and the weighting factor is quite successful by simulation examples.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.9
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• pp.1415-1421
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• 2004

In this study, a position synchronous control algorithm applied to two-axes pneumatic cylinder driving apparatus is proposed. The position synchronous control algorithm is composed of position controller and synchronous controller. The position controller is designed to minimize the effect of several nonlinear characteristics peculiar to the pneumatic cylinder driving apparatus on position control performance. The synchronous controller is designed to reduce the synchronous error. The effectiveness of the proposed control algorithm is proved by experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.253-256
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• 1997

This paper proposes a control strategy of position and force control in the same direction based on hybrid position/force control. In order to control position and force in the same direction, a weighting matrix is introduced instead of a selection matrix suggested by Raibert and Craig. The major part of the controller output comes from the position controller when a position control error is large, from the force controller when a position control error is large. The proposed algorithm is implemented by the simulation and experiment focusing on the peg-in-hole task where friction exist significantly and is not constant. It also adopts and event control scheme for more efficient performance.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1254-1258
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• 2004

This paper presents of position control of Permanent Magnet Synchronous Motor (PMSM) the implementation with Field Programmable Gate Array (FPGA) is proposed. Cascade control with inner loop as a current control and an outer loop as a position control is chosen for simplicity and fast response. FPGA is a single chip (single processing unit), which will perform the following tasks: receive and convert control signal, create a reference current signal, control current and create switch signal and act as position controller in a addition of zero form. The 10 kHz sampling frequency and 25 bit of floating point data are defined in this implementation.The experimental results show that the performance of FPGA based position control is comparable with the hardware based position control, with the advantage of control algorithm flexibility

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.308-310
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• 1994

Position control for robot manipulator may not suffice when any contacts are made between the end-effector and various environments. Therefore interaction forces must be controlled in tasks performed by robot manipulator. In general, there are two types of force control for robot manipulator. One is a stiffness control and the other is a hybrid position/force control. Stiffness control is that environment can be modeled as a spring and utilizes the desired normal force to determine the desired normal position. Hybrid position/force control, however, can be used for robot manipulator to track position and force trajectories simultaneously. This paper will compare the result of the hybrid position/force control method with that of the stiffness control method.

• Journal of Power System Engineering
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• v.8 no.4
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• pp.24-30
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• 2004

In this study, a position synchronous control algorithm applied to two-axes pneumatic cylinder driving apparatus is proposed. The position synchronous control algorithm is composed of position controller and synchronous controller. The position controller is designed to minimize the effect of several nonlinear characteristics peculiar to the pneumatic cylinder driving apparatus on position control performance. The synchronous controller is designed to reduce the synchronous error. The effectiveness of the proposed controller is proved by simulation results.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.638-641
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• 1992

In this paper, a hybrid position/force control scheme is proposed. The control scheme modifies the position command for force control against constraint surface of environment and is very simply designed and implemented. The merits of the control scheme are that it can cope with change of constraint conditions and small position inaccuracy of the environment. A constraint surface position observer is also proposed to reduce disturbances on controlled force.