• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.5
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• pp.40-47
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• 2012

The PMSM position sensor using two rectangular hall sensors can restrictively acquire the 90[$^{\circ}$] position information of rotor according to electrical angle. Thus, the control method using this position sensor cannot react properly to a rapid load torque change. On the other hand, even though a sensorless method has the advantage of acquiring instantaneous rotor position information, the accuracy of position sensor can be determined by the gain value of estimator. This paper suggests a robust speed control method on torque fluctuation condition, which combines low cost two rectangular hall sensors and sensorless control method.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.743-746
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• 1996

A hybrid control scheme to regulate the force and position by dual arms is proposed, where two arms are treated as one arm in a kinematic viewpoint. Our approach is different from other hybrid control approaches which consider robot dynamics, in the sense that we employ a purely kinematic based approach for hybrid control, with regard to the nature of position-controlled industrial robots. The proposed scheme is applied to sawing task. In the sawing task, the trajectory of the saw grasped by dual arms is planned in an offline fashion. When the trajectory of the saw is planned to follow a line in a horizontal plane, 3 position parameters are to be controlled(i.e, two translational positions and one rotational position). And a certain level of contact force has to be controlled along the vertical direction(i.e., minus z-direction) not to loose the contact with the object to be sawn. Typical feature of sawing task is that the contact position where the force control is to be performed is continuously changing. Therefore, the kinematic mapping between the force controlled position and the joint actuators has to be updated continuously. The effectiveness of the proposed control scheme is experimentally demonstrated. The proposed hybrid control scheme can be applied to arbitrary dual arm systems, regardless of their kinematic structure and the number of actuated joints.

• Journal of Drive and Control
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• v.13 no.3
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• pp.32-38
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• 2016

For this paper, the position-control performances of dual EHA(electro-hydrostatic actuator) systems were investigated according to two cases wherein the double-rod- and single-rod-type hydraulic cylinders were combined. Since the control performance is significantly dependent on the load conditions including external forces such as the inertia load, it is proposed here that the two sub-EHAs are driven by separate position and force controllers, instead of two identical position controllers. According to the simulation results, the best performance was achieved by the position-controlled single-rod-type EHA that was combined with a force-controlled double-rod-type EHA. As the force-controlled double-rod-type EHA compensated for the external loads on the position-controlled single-rod-type EHA, the position-control performance was not influenced by external forces including the inertia load. In addition, the position-controlled single-rod-type EHA contributed to the enhancement of the damping ratio by absorbing the pressure peaks through its internal accumulator. Due to the symmetrical piston areas, the double-rod-type EHA is more suitable for force control than the single-rod- type EHA.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.10
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• pp.915-921
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• 2004

In this paper, a variable structure controller(VSC) is used to control the position of the hydraulic servo system subjected to unknown disturbances. The system consists of two cylinders, which connected in series. One cylinder executes position control, the other executes force control to generate disturbances. In order to control each cylinder, interaction must be considered between two cylinders because two cylinders are connected in series. Therefore, the controller is designed regarding interaction between two cylinders as disturbances. Performance of the proposed controller was verified through experiments and compared to PID controller. The experiments showed that the proposed controller had a good performance and robustness.

• Journal of Power System Engineering
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• v.5 no.3
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• pp.104-113
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• 2001

This paper describes a precise position synchronous control of two axes rotating system using BLDC motors and a cooperative control based on decoupling technique and PI control law. The system is required performances both good speed following and minimum position synchronous errors simultaneously. To accomplish these goals, the three kinds of controllers are designed. At first, the current and speed controller are designed very simply to compensate the influences of disturbances and to follow up speed references quickly. Especially, the two degree of freedom PI controller is used considering both good tracking for speed reference input and quick rejection of disturbances in speed controller. Finally, a position synchronous controller is designed as a simple proportional controller to minimize position synchronous errors. The validity of the proposed method is confirmed through some numerical simulations. Moreover, the results are compared to the conventional master-slave control ones to show the effectiveness of the proposed system.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.9
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• pp.87-94
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• 2000

In this paper we discuss the control scheme on cooperative control of two flexible manipulators working in 3D space. We propose a control scheme which consists of hybrid position/force control and vibration suppression control. Hybrid position/force control is extended from the scheme for two cooperating rigid manipulators to that for flexible ones. in addition to the control vibration suppression control based upon a lumped-mass-spring model of the flexible manipulators is applied. To illustrate the validity of the proposed control scheme we show experimental results. in the experiment a rigid object is handled by two cooperating flexible manipulators in 3D space.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.24.2-27
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• 1996

This paper is a study on the fuzzy force control of a miniature gripper driven by piezoelectric bimorph actuator. The system is composed of two flexible cantilevers, a stepping motor, a laser displacement transducer and two semiconductor force sensors attached to the beams. Obtained results show that the present artificial finger system works well as a miniature gripper, which produces approximately 0.06N force in the maximum. Further, the fuzzy position/force control algorithm is applied to the soft-handing gripper for stable grasping of a object. It revealed that the fuzzy rule-based controller be efficient controller for the stable drive of the flexible miniature gripper. It also showed that two semiconductor strain gauges located in the flexible beam play an important roles for force control, position control and vibration suppression control.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.2
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• pp.190-196
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• 2000

A hybrid position/force control scheme to regulate the force and position by dual arms is proposed where two arms are treated as one rm in a kinematic viewpoint. The force error calculated from the information of two force/torque sensors attached to the end of each arm is transferred to minimum configuration space coordinates and then is distributed to total system joint coordinates, The position adjustment at the total con-figuration coordinates is computed based on the effective compliance matrix with respect to total joint coordinates which is obtained by coordinate transformation between the task coordinates and the total joint coordinates. The proposed scheme is applied to sawing task. When the trajectory of the saw is planned to follow a line in a horizontal plane 2 position parameters are to be controlled(i.e., two translational positions) Also a certain level of contact force has to be controlled along the vertical direction(i.e. minus z-direction) not to loose the contact with the object to be sawn. We experimentally show that the performance of the velocity and force response are satisfactory. The proposed hybrid control scheme can be applied to arbitrary two cooperating arm system regardless of their kinematic structure and the number of actuated joints.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.536-542
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• 2002

There are two important variables in machining process control, which are feed and cutting speed. In this work, a two degree-of-freedom controller is designed and implemented to achieve on-line cutting force control and position control based on the modelling of cutting process dynamics which are established through step response test. Two schemes are proposed and implemented. The first is feed control under the constant spindle speed and spindle speed control under the constant feed speed. The second is a simultaneous control of feed and spindle speed. The last performs a position control under the constant cutting force. Those are confirmed to work properly. Especially the latter shows a faster response.