• Journal of Institute of Control, Robotics and Systems
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• v.19 no.11
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• pp.1011-1016
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• 2013

Patients have the paralysis of their wrists, and can't use of their wrists freely. But their wrists can be recovered by wrist-bending rehabilitation exercise. Professional rehabilitation therapeutists exercise the wrists of patients in hospital. But the wrists of patients have not exercised enough for the rehabilitation, because the therapeutists are much less than patients in number. Therefore, the wrist rehabilitation robot should be developed, and it have to measure the applied force to the patients' wrists for their safety. In this paper, the four-axis force/moment sensor was designed for the wrist rehabilitation robot. As a test results, the interference error of the four-axis force/moment sensor was less than 0.91%. It is thought that the sensor can be used to measure the applied force to the patients' wrists.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.5
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• pp.259-267
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• 2019

This paper proposes a structure of a variable impedance control system based on sensor-less external force estimator of industrial manipulators for cyber physical production systems (CPPS). To implement CPPS, a feedback system is constructed by using the robot operating system (ROS) and an external force estimator which is designed to measure the external force applied to the manipulator without a force sensor. Based on the robot dynamics, the robot-human cooperating system for the cyber physics production system is implemented through a controller that changes the impedance characteristics of the manipulator according to the situation using the external force estimator. Simulation and experimental results verify the effectiveness of the proposed control system.

• Journal of Sensor Science and Technology
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• v.26 no.5
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• pp.353-359
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• 2017

This paper describes the design and manufacture of a ankle two-axis force sensor of a walking assist robot for hemiplegic leg patient. The walking assist robot for the hemiplegic leg patient can safely control the robot by detecting whether the foot wearing the walking assist robot is in contact with the obstacle or not. To do so, a two-axis force sensor should be attached to the robot's ankle. The sensor is used to measure the force of a patient's ankle lower part. The two-axis force sensor is composed of a Fx force sensor, a Fy force sensor and a pulley, and they detect the x and y direction forces, respectively. The two-axis force sensor was designed using by FEM(Finite Element Method), and manufactured using by strain-gages. The characteristics experiment of the two-axis force sensor was carried out respectively. The test results indicated that the interference error of the two-axis force sensor was less than 1.2%, the repeatability error and the non-linearity of the two-axis force sensor was less than 0.04% respectively. Therefore, the fabricated two-axis force sensor can be used to measure the force of ankle lower part in the walking assist robot.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.116.3-116
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• 2002

Introduction $\textbullet$Teleoperation System for Wiping Operation $\textbullet$Virtual Force Generation Algorithm $\textbullet$Virtual Velocity Generation Algorithm $\textbullet$Force-Force Control Technique $\textbullet$Experimental Results and Discussion $\textbullet$Conclusions

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.150-156
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• 1996

Static variations of cutting forces are estimated using spindle motor current. Static sensitivity of spindle motor current is higher than feed motor current. The linear relationship between the cutting force and RMS value of the spindle motor current is obtained. Using cutting force estimation, tool overload in milling process can be well detected, and cutting force is regulated at a constant level by feedrate adaptive control.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.129.5-129
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• 2001

When a robot manipulator performs some task like grinding or assembling, not only the position control but also the force control of the tools connected to the robot must be controlled. But at this time We were received the uncertainty problems of system information for the force control, for example disturbance, senor resolution and measurement noise. Therefore we proposed fuzzy logic control method instead of existing control theory for the robot manipulator control, for example PID control method. In this paper, We proposed hybrid position/force control of robot manipulator using fuzzy logic control method. To show the validity of the proposed fuzzy controller, We compared fuzzy controller with conventional PID controller.

• Smart Structures and Systems
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• v.5 no.1
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• pp.69-79
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• 2009

A non-clipped semi-active stochastic optimal control strategy for nonlinear structural systems with MR dampers is developed based on the stochastic averaging method and stochastic dynamical programming principle. A nonlinear stochastic control structure is first modeled as a semi-actively controlled, stochastically excited and dissipated Hamiltonian system. The control force of an MR damper is separated into passive and semi-active parts. The passive control force components, coupled in structural mode space, are incorporated in the drift coefficients by directly using the stochastic averaging method. Then the stochastic dynamical programming principle is applied to establish a dynamical programming equation, from which the semi-active optimal control law is determined and implementable by MR dampers without clipping in terms of the Bingham model. Under the condition on the control performance function given in section 3, the expressions of nonlinear and linear non-clipped semi-active optimal control force components are obtained as well as the non-clipped semi-active LQG control force, and thus the value function and semi-active nonlinear optimal control force are actually existent according to the developed strategy. An example of the controlled stochastic hysteretic column is given to illustrate the application and effectiveness of the developed semi-active optimal control strategy.

• International Journal of Control, Automation, and Systems
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• v.3 no.1
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• pp.70-78
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• 2005

This paper presents hybrid control of displacement and force in a Medical Tele-Analyzer by disturbance observer-based controller which is robust to internal and external disturbances; model uncertainty, load, and friction for instances. The developed Medical Tele-Analyzer consists of 2 subsystems; doctor-side subsystem and patient-side subsystem. In the doctor side subsystem, an array of displacement sensor is equipped to detect movement of doctor's hand and fingers. The detected information is transmitted to the patient side to be used in medical analysis. On the other hand, the patient-side subsystem consists of an array of displacement actuators, which is used to follow displacement of doctor's hand and fingers. An array of force sensors is used to detect forces between patient and the equipment. Since displacement control in patient side is coupled with force control in doctor side and vice-versa, design of the controller has to take into account this coupling. Not only using in medical tele-analysis, the proposed system can also be used in any tele-displacement-force controls of industrial processes.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.1
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• pp.174-184
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• 1997

This paper presents a robust force tracking control of a smart flexible gripper featured by a piezoceramic actuator characterizing its durability and quick response time. A mathematical governing equation for the proposed gripper structure is derived by employing Hamilton's principle and a state space control model is subsequently obtained through model analysis. Uncertain system parameters such as frequency variation are included in the control model. A sliding mode control theory which has inherent robustness to the sys- tem uncertainties is adopted to design a force tracking controller for the piezoceramic actuator. Using out- put information from the tip force sensor, a full-order observer is constructed to estimate state variables of the system. Force tracking performances for desired trajectories represented by sinusoidal and step func- tions are evaluated by undertaking both simulation and experimental works. In addition, in order to illustrate practical feasibility of the proposed method, a two-fingered gripper is constructed and its performance is demonstrated by showing a capability of holding an object.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.33-35
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• 2004

In this paper, web based monitoring systems are implemented for multi-axis force control systems of an intelligent robot. Linux operating systems are ported to an embedded system which Include a Xscale processor to implement a web based monitoring system. A device driver is developed to receive data from multi-axis force sensors of intelligent robots. To control this device driver, a socket program for Labview is also developed.