• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1808-1813
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• 2005

In this paper, we present the finger tip tactile sensor which can detect contact normal force as well as slip. The developed sensor is made of two different materials, such as polyvinylidene fluoride(PVDF) that is known as piezoelectric polymer and pressure variable resistor ink. In order to detect slip to surface of object, a PVDF strip is arranged along the normal direction in the robot finger tip and the thumb tip. The surface electrode of the PVDF strip is fabricated using silk-screening technique with silver paste. Also a thin flexible force sensor is fabricated in the form of a matrix using pressure variable resistor ink in order to sense the static force. The developed tactile sensor is physically flexible and it can be deformed three-dimensionally to any shape so that it can be placed on anywhere on the curved surface. In addition, we developed a tactile sensing system by miniaturizing the charge amplifier, in order to amplify the small signal from the sensor, and the fast signal processing unit. The sensor system is evaluated experimentally and its effectiveness is validated.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.390-390
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• 2000

This research is the development of a skin-type tactile sensor for service robot using PVDF film for the detection of the contact state. The Prototype of the tactile sensor which has 8$\times$8 taxels was fabricated using PVDF film In the fabrication procedure of the sensor, the electrode patterns and common electrode of the thin conductive tape were attached to the both side of the 28 micro meter thickness PVDF film using conductive adhesive. The sensor was covered with polyester film for insulation and attached to the rubber base for making stable structure. The signals of a contact pressure to the tactile sensor were sensed and processed in the DSP system in which the signals were digitized and filtered. Finally, the signals were integrated for taking the force profile. The processed signals of the output of the sensor were visualized in PC, the shape and force distribution of the contact object were obtained. The reasonable performance for the detection of contact state was verified through the experiment.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.6
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• pp.411-416
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• 2016

This paper presents the design methodology of an unknown input observer for Lipschitz nonlinear systems with unknown inputs in the framework of convex optimization. We use an unknown input observer (UIO) to consider both nonlinearity and disturbance. By deriving a sufficient condition for exponential stability in the linear matrix inequality (LMI) form, existence of a stabilizing observer gain matrix of UIO will be assured by checking whether the quadratic stability margin of the error dynamics is greater than the Lipschitz constant or not. If quadratic stability margin is less than a Lipschitz constant, the coordinate transformation may be used to reduce the Lipschitz constant in the new coordinates. Furthermore, to reduce the maximum singular value of the observer gain matrix elements, an object function to minimize it will be optimally designed by modifying its magnitude so that amplification of sensor measurement noise is minimized via multi-objective optimization algorithm. The performance of UIO is compared to a nonlinear observer (Luenberger-like) with an application to a flexible joint robot system considering a change of load and disturbance. Finally, it is validated via simulations that the estimated angular position and velocity provide true values even in the presence of unknown inputs.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.5
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• pp.16-21
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• 2022

This study investigates the effect of the deformation on the sensitivity of a flexible polydimethylsiloxane (PDMS) membrane sensor. A PDMS membrane sensor was developed to measure the impact force of a water droplet using a silver nanowire (AgNW). The initial deformation of the membrane was confirmed with the application of a tensile force (i.e., tension) and fixing force (i.e., compressive force) at the gripers, which affects the sensitivity. The experimental results show that as the tension applied to the membrane increased, the sensitivity of the sensor decreased. The initial electrical resistance increased as the fixing force increased, while the sensitivity of the sensor decreased as the initial resistance increased. The movement of the membrane due to the impact force of the water droplet was observed with a high-speed camera, and was correlated with the measured sensor signal. The analysis of the motion of the membrane and droplets after collision confirmed the periodic movement of not only the membrane but also the change in the height of the droplet.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.2
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• pp.265-276
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• 2024

The future battlefield operation concept does not focus on advanced and complete weapon systems, but requires a new battlefield operation concept that can effectively demonstrate offensive power by combining a large number of low-cost, miniaturized weapons. Recently, research on the autonomous application of major technologies that make up the mission control system is actively underway. However, since the mission control system is still dependent on the operator's operating ability when operating multiple robots, there are limitations to simply applying the automation technology of the existing mission control system. Therefore, we understand how changes in operator capabilities affect multi-robot operation and propose an adaptive mission control architecture design method that supports multi-robot integrated operation by adjusting the level of autonomy of the mission control system according to changes in operator capability.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.4
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• pp.485-492
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• 2006

This paper deals with implementation of network for distributed control system of a humanoid robot ISHURO(Inha Semyung Humanoid Robot). A humanoid robot needs much degree of freedom structurally and much data for having flexible movement. To realize such a humanoid robot, distributed control method is preferred to the centralized one since it gives a compactness, modularity and flexibility for the controllers. For organizing distributed control system of a humanoid robot, a control processor on a board is needed to individually control the joint motor and communication technology between the processors is required to transmit its information within control time. The processor is DSP-based processor and includes CAN network on a chip. It shares the computational load such as monitoring the sensor information and controlling the actuator between each of modules. In this paper, the communication architecture is suggested and its message protocol are discussed including message structure, time consumption for transmission, and controller structure at the view of distributed control for a humanoid robot. All of the sequence are simulated with Matlab and then verified with real walking experiment by ISHURO.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.4
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• pp.443-448
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• 2006

In this paper, a novel method is proposed for generating the low-power and stable walking trajectory of biped robots, and then a biped robot with 25 DOFs(degrees of freedom) is designed and implemented for the realization of the low-power walking trajectory generated by the proposed method. In our method, first a stable VPCG(vertically projected center of gravity) trajectory is generated, and then the trajectories of ankle and pelvis of a biped robot are planned to follow the preplanned stable VPCG trajectory, which produces a waking pattern without bending its knees and enables a biped robot to walk with less power consumption. On the other hand, a biped robot implemented in this paper has the mechanical structure of foot that enables a biped robot to support on the ground well, and the mechanical structure of pelvis that enables a biped robot to move flexibly. From results of the walking experiment and power consumption measurement, it was confirmed that the proposed method can generate the more stable and flexible trajectory with less power consumption compared with the existing methods which do not use the ankle of a biped robot.

• Korean Journal of Optics and Photonics
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• v.13 no.4
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• pp.283-288
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• 2002

Unlike rigid parts, flexible parts can be deformed by contact force during assembly. In robotic assembly, information about their deformation as well as possible misalignment between the holes and their respective mating parts is essential for successful assembly. This paper presents a method to design a visual sensing system for measuring parts deformation and misalignment in flexible parts assembly. This paper performs ray-trace analysis of the system. A series of experiments for flexible parts assembly by using the implemented system are performed.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.212-218
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• 2002

This research is the development of a distributed tactile sensor using PVDF film far the detection of the contact state. The prototype of the tactile sensor with 8$\times$8 taxels was fabricated using PVDF film and flexible circuitry. In the fabrication procedure, the electrode and the common electrode patterns are attached to the both side of the 28${\mu}m$ thickness PVDF film. The sensor is covered with polyester film for insulation. The signals of a contact pressure to the tactile sensor are sensed and processed in the DSP system in which the signals are digitalized and filtered. And the signals are integrated for taking the force profile. The processed signals of the output of the sensor are visualized to take the shape and force distribution of the contact object in personal computer. The usefulness of the sensor system is verified through the sensing examples.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.5
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• pp.591-598
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• 2011

Tip position control of a flexible cantilever is difficult due to the non-minimum phase dynamics that result from the finite propagating speed of a mechanical wave along the cantilever. In this paper, we propose a method for the tip position control using a light and cheap accelerometer that does not bring any significant change to the dynamics of the cantilever system. The linear system identification model of the flexible cantilever is obtained with measurements by a laser displacement sensor. A Kalman estimator is designed with this model and calculates the estimated tip position with the acceleration data of the accelerometer that is attached on the tip of the cantilever. To verify reliability of the estimator, the estimated tip position is used to the feedback control system that uses a fuzzy logic controller. The control results are compared with those of the fuzzy control system where the real tip position is measured by a laser displacement sensor. Also, the performance of the estimator with the accelerometer is presented and discussed.