• Journal of the Korean Society for Precision Engineering
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• v.28 no.5
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• pp.599-605
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• 2011

A 3-D rehabilitation robot system is developed. The robot system is for the rehabilitation of upper extremities, especially the shoulder and elbow joints, and has 3-D workspace for occupational therapy to recover physical functions in activities of daily living(ADL). The rehabilitation robot system has 1 DOF in horizontal rotational motion and 2 DOF in vertical rotational motion, where all actuators are set on the ground. Parallelogram linkage mechanisms lower the equivalent inertia of the control elements as well as control forces. Also the mechanisms have high mechanical rigidity for the end effector and the handle. In this paper, a hybrid position/force controller is used for controlling positions and forces simultaneously The controller is tuned according to the robot posture. The active motion modes for rehabilitation program consist of active-resisted motion mode and active-free motion mode. The results of the experiments show that the proposed motion modes provide the intended forces effectively.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.795-798
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• 1991

The hybrid positon/force control is required when two or more robots perform a coorperative task in a uncertain environment, or when single robot does a task with a constant force to the environment. In this paper, a new control algorithm which control simultaneously the position and the force are proposed, however, especially the conventional position controller employed in the present robot control is used. Moreover, in order to improve the output response characteristics of the system, the PI gains which were computed from the PI gain tunning techniques, are varied based on the results of the Fuzzy algorithm.

• The Journal of Korea Robotics Society
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• v.8 no.2
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• pp.67-74
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• 2013

This paper presents interaction force control between a balancing robot and a human operator. The balancing robot has two wheels to generate movements on the plane. Since the balancing robot is based on position control, the robot tries to maintain a desired angle to be zero when an external force is applied. This leads to the instability of the system. Thus a hybrid force control method is employed to react the external force from the operator to guide the balancing robot to the desired position by a human operator. Therefore, when an operator applies a force to the robot, desired balancing angles should be modified to maintain stable balance. To maintain stable balance under an external force, suitable desired balancing angles are determined along with force magnitudes applied by the operator through experimental studies. Experimental studies confirm the functionality of the proposed method.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.10
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• pp.507-513
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• 2003

Nowadays, the necessity of linear position control motors have been increased in the various fields of the automatic control system. In the recently, the position control motor have disadvantaged in the efficiency and economical view since it require a conversion equipments such as belt and gear in order to convert rotary to linear motion. On the contrary, the hybrid linear stepping motor(HLSM) of linear motion digital actuator has a direct drive method that do not need mechanical conversion equipments. Therefore, the HLSM is better advantaged in the efficiency and economical view than a rotary stepping motor. In this paper, we have designed an optimum tooth shape and a permanent magnet value between the mover teeth by the 2D finite element method(FEM) to develop the HLSM with longitudinal flux machine(LFM) type, and calculated the thrust force and normal force. And we have manufactured the prototype of it. and have experimented the thrust force and the dynamic thrust characteristics of it.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.2
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• pp.207-216
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• 1991

In the case that the robot manipulator should respond to the variance and uncertainty of the environment in performing preforming precision tasks, it is indispensable that the robot utilizes the various sensors for intrlligence. In this paper, the robot force control method is implemented with a force/torque sensor, two personal computers, and a PUMA 560 manipulator for performing the various application tadks. The hybrid position/force control method is used to control the force and position axis separately. An interface board is designed to read the force/torque sensor output into the computer. Since the two computers should exchange the information quickly, a common memory board is designed. Before the algorithms of application tasks are developed, the basic force commands must be supplied. Thus, the MOVE-UNTIL command is used at the discrete time instant and, the MOVE-COMPLY is used at the continuous time instant for receiving the force feedback information. Using the two basic force commands, three application algorithms are developed and implemented for edge-following, insertion, and grinding tasks.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.1
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• pp.100-104
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• 1998

A hybrid control method based on the relative motion between a manipulator and a workpiece is described for a two-dimensional manipulator, in which it is assumed that there are no collisions between the robot manipulator and the workpiece, and that we use a computed force law which is similar to the computed torque law in the trajectory tracking problem of a robot manipulator. The effectiveness of the proposed hybrid control method is illustrated through several simulations.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.4
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• pp.449-454
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• 2010

The force control of a constrained flexible manipulators has been one of the major research topics. However, a little effort has been devoted for the relation between friction force and elastic deflection of end-effector for a constrained flexible manipulator. So, the aim of this paper is to clarify the friction mechanism of a constrained spatial multi-link flexible manipulator by changing the material and connected method of end-effector. In this study, a concise hybrid position/force control scheme is applied to the control of a flexible manipulator, and the experimental results for the constrained vertical motion and constrained horizontal motion is presented. Finally a comparison between these results are presented to show the reduction of vibration of link and friction force.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.917-922
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• 2004

As the tasks of robots become more diverse, some complicated tasks have come to require force and position hybrid control. A compliant device can be used to control force and position simultaneously by separating the twist of the robot's end effector from the twist of compliance and freedom by using stiffness mapping of the compliant device. The development of a fuzzy gain scheduling scheme of control for a robot with a compliant device is described in this paper. Fuzzy rules and reasoning are performed on-line to determine the gain of twists based on wrench error and twist error and twist of compliance and twist of freedom ratio. Simulation results demonstrate that better control performance can be achieved in comparison with constant gain control.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.189-195
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• 2000

For free motions, vibration suppression of flexible manipulators has been one of the hottest research topics. However, for constrained motions, a little effort has been devoted for vibration suppression control. Using the dependency of elastic deflections of links on contact force under static conditions, vibrations for constrained planar two-link flexible manipulators have been suppressed successfully by controlling the contact force. However, for constrained spatial multi-link flexible manipulators, the vibrations cannot be suppressed by only controlling the contact force. So, the aim of this paper is to clarify the vibration mechanism of a constrained, multi-DOF, flexible manipulator and to devise the suppression method. We apply a concise hybrid position/force control scheme to control a flexible manipulator modeled by lumped-parameter modeling method. Finally, a comparison between simulation and experimental results is presented to show the performance of our method.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.460-463
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• 1995

The present paper studies a robot manipulator's contact tasks on the uncertain flexible objects. The flexible object's distributed parameter model is approximated into a lumped "position state-varying" model. By using the well-known nonlinear feedback compensation, the robot's control space is decomposed into the position control subspace and the object's torque control subspace. The optimal state feedback is designed for the position loop, and the robot's contact force is controlled through controlling the resultant torque on the object using model-reference simple adaptive control. Experiments of a PUMA robot interacting with an aluminum plate show the effectiveness of this control approach. approach.