• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.10
• /
• pp.1065-1072
• /
• 2008

A HDD adopts a sensorless brushless DC (BLDC) motor as a spindle motor. Because there is no direct sensor measuring rotor position. open loop commutations with inductive sensing are used to increase the rotor speed up to a certain speed where the zero crossings of the back electromotive force (EMF) voltage are measurable. Therefore, successful open loop commutations are necessary for the stable start-up control of the spindle motors. In this paper, the time scale and the number of the open loop commutations are employed for design parameters to guarantee robustness to torque constant variation and initial rotor position. The design results are verified by experiments on a very low current start-up of the spindle motor with various environment. The experimental results show that the design results can decrease the start-up failure rate considerably.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.11
• /
• pp.171-179
• /
• 2003

This paper presents a rehabilitation exercise system which utilizes a 6 DOF robot as a motion generator. This system was proposed for a stroke patient or a patient who has hemiplegia. A master-slave system was designed to exercise either paralysis or abnormal limb by using normal limb motion. The study on the human body was applied to calculate the motion range of elbows and shoulders. In addition, a force-torque sensor was applied to the slave robot to estimate the rehabilitation extent of the patient. Therefore, the stability of the rehabilitation robot could be improved. By using the rehabilitation robot. the patients could exercise by themselves without assistance. In conclusion, the proposed system was verified by computer simulations and system experiment.

• Proceedings of the KIEE Conference
• /
• 2006.07d
• /
• pp.1789-1790
• /
• 2006

This paper reports a new test facility to investigate the characteristics of the thrusters mounted on the small scale underwater vehicle using Force/Torque sensor. With the test facility proposed here, No disassembly needs be made to the target vehicle, which makes us possible to get the realistic forces of the vehicle rather than the fortes of the thrusters themselves. Experimental data analyses, heave, sway, and surge, for the QI ROV are given as an example of this method.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.118.5-118
• /
• 2002

To apply induction hardening method to a press die having 3-D free surface, the induction hardening tool moves on a press die above 1～2mm gap with constant velocity. Since the induction hardening process requires its own hardening path for each die, a direct teaching method which generates working path directly guided by operators is more suitable than an offline method using CAD/CAM data. The direct teaching apparatus in this work includes a teaching tool with a force/torque sensor and data processing computer to finally generate robot's Induction hardening program , in direct teaching operation, an operator teaches working path maintaining contact with surface of press die by holding...

• International Journal of Aeronautical and Space Sciences
• /
• v.8 no.1
• /
• pp.105-114
• /
• 2007

This article presents the details of a designed control moment gyroscope (CMG) with a constant speed momentum wheel and one-axis-gimbal, and its experimental results performed at Korea Aerospace Research Institute. The CMG which is able to produce a torque of lOO mNm per each, is mounted in a pyramid configuration with four SGCMGs. Each CMG test and a single axis maneuver test with four-CMG cluster configuration are performed to confirm their performance on a ground-test facilities consisted of three major parts: a vibration isolation system, a dynamic force plate (Kistler sensor), and a DSP board. These facilities provide the accurate data of three axial and torques from the control moment gyro. Details of the CMG experimental results are presented with discussion of the experimental errors. The experimental data are compared with theoretical results and both results are used to verify their performance specifications.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10b
• /
• pp.896-901
• /
• 1990

A simulation analysis is presented for the position control of a single-link flexible manipulator whose end-effector is subjected to an impulsive force. Arm is rotated by a d.c. servomotor at the shoulder so that the end point stays precisely at its initial position even if the end effector is thumped with the impulsive loading. A gap sensor is used to measure the tip displacement. The control torque based on the PD control law is applied to the motor through the driver circuit. The control strategy is tested by means of computer simulation for the one-link flexible-arm prototype in the authers' laboratory at Tohoku Univ.

• Proceedings of the IEEK Conference
• /
• 2000.06e
• /
• pp.39-42
• /
• 2000

In this paper we design the robust impedance controller of the robot manipulator with time delay. The designed controller considers time delay in the position loop and stabilizes the closed-loop system. The performance of a controller can be easily degraded by external disturbances. To improve the performance when external disturbances exist, we use the disturbance observer to handle the disturbances in the velocity loop and provide robustness to the control system. To show the validity of the designed controller, several experiments are performed for the 5-DOF robot manipulator equipped with the wrist force/torque sensor system.

• Proceedings of the KIEE Conference
• /
• 1998.07g
• /
• pp.2305-2308
• /
• 1998

In this paper, a control algorithm which enables robot to cooperate with human is proposed. The method senses the humanbeing's intention by using force/torque sensor attached at the end effector and moves and cooperates as intended by humanbeing. The method also considers safety of the humanbeing by adjusting and limiting the robot speed automatically. The proposed method is verified its performance by computer simulation and experiments for the 2-DOF DD(Direct Drive) Arm in real-time

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.1130-1132
• /
• 2000

In this paper, For Control of the speed sensorless induction motor propose the method which is controled the motor by operating two axis current in input current of the inverter. This method determines frequency of inverter in order to stator electromotive force and E/F ratio for the setting magnetic flux, drives for speed control using a voltage power converter of the induction motor by means of voltage fed converter with current control ability.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.23 no.5
• /
• pp.421-427
• /
• 2014

In this paper, the kinestatic control algorithm using a six-axis compliant device is presented. Unlike the traditional control methods using a force/torque sensor with very limited compliance, this method employs a compliant device to provide sufficient compliance between an industrial robot and a rigid environment. This kinestatic control method is used to simply control the position of an industrial robot with twists of compensation, which can be decomposed into twists of compliance and twists of freedom. A simple design method of a six-axis parallel-type compliant device with a diagonal stiffness matrix is presented. A compliant device prototype and kinestatic control hardware system and programming were developed. The effectiveness of the kinestatic control algorithm was verified through two kinds of kinestatic control experiments.