• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.2
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• pp.10-19
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• 1996

This paper presents a finger-shaped multisensor system which can measure the tyep and position of a target surface by contactl. The multi-sensor system consists of a sphere-shpaed optical tactile sensor located at the finger tip and a force/torque sensor located at the joint of a finger. The optial tactile sensor determines the type and position of the target surface using the shape and position of the CCD image of the touching area generated by a contact between the sensor and the taget surface. The force/torque sensor also determines the position and surface normal vector by applying the distributionof forces and torques t the contact point to the equations of finger shape. The measurements on the position and surface normal vector at a contact point obtined by two individual sensors are fused using a statistical method. The integrated sensor system has 0.8mm error in position measurement and 1.31$^{\circ}$ error in normal vector measurement. The developed sensor system has many applications, such as autonomous compliance control, automatic grasping and recognition, etc.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.206-212
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• 2000

This paper presents a hybrid actuator scheme to actively control the end-point position and vibration of a two-link flexible robot arm. Control scheme consists of four different actuators; two servo-motors at the hubs and two piezoceramics bonded to the surfaces of the flexible links. Two sliding hyperplanes are designed for two servo-motors which have time varying parameters to maintain control performance in any configuration. The surface gradients of the hyperplanes are determined by pole assignment technique to guarantee the stability on the hyperplanes themselves. During the motion, undesirable oscillations caused by the torques based on the rigid link dynamics are actively suppressed by applying feedback control voltages to the piezoceramic actuators. Consequently, desired tip motion is achieved. In order to demonstrate the effectiveness of the proposed methodology, experiments are performed for the regulating and tracking control problems.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.2
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• pp.63-70
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• 2018

In this paper, the design of a novel 6-axis compliance device with force/torque sensing capability and the experiment results on force measurement are presented. Unlike the traditional control methods using a force/torque sensor with very limited compliance, the force control method employs a compliant device to provide sufficient compliance between an industrial robot and a rigid environment for more stable force control. The proposed compliance device is designed to have a diagonal stiffness matrix at the tip and uses strain gauge measurement which is robust to dust and oil. The measurement circuit is designed with low-cost IC chips however the force resolution is 0.04N.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.892-897
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• 1987

The ability of a robotic manipulator to recognize the shape of an object by feeling its band around the object is useful in many applications. Two-dimensional object contour tracking by force feedback is described. The system consists of IBM PC/AT, PUMA 560 manipulator, PUMA controller and a tip sensor. Position control is accomplished by using VAL command and the unmodified PUMA controller. A contour tracking algorithm is developed and tested on three different types of objects. The experimental results show that the objects' shapes can be successfully identified.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.6
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• pp.615-621
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• 2013

The robot calibration has greatly improved the absolute accuracy of the industrial robot. However, the accuracy of the relative positions of robotic tool-tip at work-points on a work-piece is only slightly corrected by the robot calibration since there has been no practical method to eliminate the elements of the setup position errors at a robotic workplace. A robotic workplace calibration is demonstrated in this paper to minimize the relative position errors between a robot tool-tip and the work-point on a work-piece. The existing teaching and playback method has been developed for the robotic workplace calibration. This paper uses the work-piece fixed in a robotic work-place as measurement equipment instead of a special robot measurement equipment for the robotic workplace calibration. The positive effect of the robotic workplace calibration is supported by the results of computer simulation on an ideal robotic workplace model and an experiment at the actual robotic workplace.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.9-13
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• 1997

This parer is a study on the inverse dynamics of a one-link flexible robot arm which is controlled by translational base motion. The system is composed of a flexible arm, a base for driving arm, a DC servomotor, and a computer. The arm base is moved so that the arm tip follows a desired function. The governing equations are based on the Bernoullie-Euler beam theory and solved by applying the Laplace transform method and then the numerical inversion method. Moter voltage is obtained by simulation for tip trajectory functions i. e. Bang-Bang, Cosine and Gauss Function. And, the tip motion is measured while simulation results are applying. Then the results are investigated to select most proper input and to compare their chateristics. Experimental results show the Cosine function is most proper with respect to low maximum voltage and steady state error.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.367-372
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• 1998

In this paper, the mathematical model of a cut with an inverted flexible beam and a concentrated tip mass was derived. The characteristic equation for calculating the natural frequencies of the cart-beam-mass system was obtained and the motion of the system was analyzed through unconstrained modal analysis. A good positioning response of the cart without excessive vibrational motion of the tip mass could be obtained through numerical simulation using PID controller with the feedback of both the position of the cart and the deflection of the beam.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.2
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• pp.89-94
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• 2001

The position control accuracy of a robot manipulator is significantly deteriorated when a long arm robot is operated at a high speed. This paper presents a very simple sliding mode control which eliminates multiple mode residual vibration in a robot manipulator. The neural network is used to avoid that sliding mode condition is deviated due to the change of system parameter and disturbance. This paper is suggested control system which designed by sliding mode controller using neural network. The effectiveness of proposed scheme is demonstrated through computer simulation.

• Journal of Korean Society of Forest Science
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• v.111 no.2
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• pp.287-301
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• 2022

This study aims to propose a crane-tip control method to intuitively control the end-effector vertically or horizontally for improving the crane work efficiency and to confirm the control performance. To verify the control performance based on experimental variables, a laboratory-scale crane was manufactured using an electric cylinder. Through a forward and reverse kinematics analysis, the crane was configured to output the position coordinates of the current crane-tip and the joint angle at each target point. Furthermore, a method of generating waypoints was used, and a dead band using lateral boundary offset (LBO) was set. Appropriate parameters were selected using bang-bang control, which confirmed that the number of waypoints and LBO radius were associated with positioning error, and the cylinder speed was related to the lead time. With increased number of waypoints and decreased LBO radius, the positioning error and the lead time also decreased as the cylinder speed decreased. Using the proportional control, when the cylinder velocity was changed at every control cycle, the lead time was greatly reduced; however, the actual control pattern was controlled by repeating over and undershoot in a large range. Therefore, proportional control was performed by additionally applying velocity gain that can relatively change the speed of each cylinder. Since the control performed with in a range of 10 mm, it was verified th at th e crane-tip control can be ach ieved with only th e proportional control to which the velocity gain was applied in a control cycle of 20 ms.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.283-286
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• 2002

This paper presents the straightness compensation system which is a device for improving the machining accuracy of ultra-precision machines by synchronizing the position of diamond tool tip with machine error motion. Sine it is actuated by piezoelectric actuator with highly nonlinear hysteresis characteristics, the feedback control schemes such as Proportional Integral(PI), are required and realized by measuring the displacements of diamond tool tip. for the better tracking performance, the controller was implemented using TMS320C32 32bit floating-point DSP which is fast so that the real-time control is possible. In addition, stand alone type DSP board was chosen fur the easy assembly into the ultra-precision machines. The experimental results show good command tracking performance and the motion error of the machine is satisfactorily compensated during the machining process.