• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.51-58
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• 2004

This paper describes the development of a small 6-axis force/moment sensor for robot's finger, which measures farces Fx, Fy, Fz, and moments Mx, My, Mz simultaneously. In order to safely grasp an unknown object using the robot's gripper, and accurately perceive the position of it in the gripper, it should measure the force in the gripping direction, the force in the gravity direction and the moments each direction, and perform the force control using the measured forces and moments. Also, it should detect the moments Mx (x-direction moment), My and Mz to accurately perceive the position of the object in the grippers. Thus, the robot's gripper should be composed of 6-axis force/moment sensor that can measure forces Fx, Fy, Fz, and moments Mx, My, Mz simultaneously. In this paper, the small 6-axis force/moment sensor for measuring forces Fx, Fy, Fz, and moments Mx, My, Mz simultaneously was newly modeled using several parallel-plate beams, designed, and fabricated. The characteristic test for the developed sensor was performed, and the result shows that intereference errors of the developed sensor are less than 4.23％. Thus, the developed small 6-axis force/moment sensor may be used a robot's gripper.

• 한국지형공간정보학회:학술대회논문집
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• 2002.11a
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• pp.58-65
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• 2002

The most widespread techniques for DEM generation are stereoscopy for optical sensor images and interfereometry for SAR images. These techniques suffer from certain sensor and processing limitations, which can be overcome by the synergetic use of both sensors and DEMs respectively. In this paper, different strategies for fusing SAR and optical data are combined to derive high quality DEM products. The multiresolution wavelet transform, which take advantage of the complementary properties of SAR and stereo optical DEMs, will be applied for the fusion process. By taking advantage of the fact that errors of the DEMs are of different nature using the multiresolution wavelet transform, affected part are filtered and replaced by those of the counterpart and is tested with two sets of SPOT and ERS DEM, resulting in a remarkable improvement in DEM. For the analysis of results, the reference DEM is generated from digital base map(1:5000).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.52-60
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• 2003

In aviation navigation using GPS, requirements on availability and integrity must be absolutely satisfied. Current study on accomplishing this integrity includes RAIM(Receiver Autonomous Integrity Monitoring), monitoring integrity internaIly in GPS receiver itself. Parity space technique as one of RAIM techniques has shown the advantages in fault detection and isolation due to each use of its magnitude and direction under the assumption of one fault. ln case of multiple fault, as biases in errors interact decreasing the effect of multiple fault in parity space, the exact fault detection and identification(FDI) may be difficult to be conducted. This paper focuses on FDI study on two faults and explains why parity space techniques applied on single fault is not adequate to the application of multiple fault case and shows that extended parity space technique may improve the performance of RAIM on two faults.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.139-145
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• 2006

LRE(Liquid propellant Rocket Engine) is one of the important parts to control the trajectory and dynamics of rocket. The purpose of control of LRE is to control the thrust according to requiredthrust profile and control the mixture ratio of propellants fed into gas generator and combustor for constant mixture ratio. It is not easy to control thrust and mixture ratio of propellants since there are co-interferences among the components of LRE. In this study, the dynamic model of LRE was constructed and the dynamic characteristics were analyzed with control system as PID control and PID+Q-ILC(Iterative Learning Control with Quadratic Criterion) control. From the analysis, it could be observed that PID+Q-ILC control logic is more useful than standard PID control system for control of LRE.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.1 s.190
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• pp.27-36
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• 2007

This paper describes the development of 6-axis ankle force/moment sensor for the intelligent feet of a humanoid robot. When the robot walks on uneven terrain, the feet should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz from the attached 6-axis force/moment sensor on their ankles. Papers have already been published have some disadvantages in the size of the sensor, the rated output and so on. The rated output of each component sensor (6-axis ankle force/moment sensor) is very important to design the 6-axis force/moment sensor for precision measurement. Therefore, each sensor should be designed to get the similar rated output under each rated load. Also, the size of the sensor is very important for mounting to robot's feet. Therefore, the diameter should be below 100 mm and the height should be below 40mm. In this paper, first, the structure of a 6-axis ankle force/moment sensor was modeled for a humanoid robot's feet newly, Second, the equations to predict the strains on the sensing elements was derived, third, the size of the sensing elements was designed by using the equations, then, the sensor was fabricated by attaching straingages on the sensing elements, finally, the characteristic test of the developed sensor was carried out. The rated outputs from the derived equations agree well with the results from the experiments. The interference error of the sensor is less than 2.94%.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1097-1102
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• 2007

This paper describes the development of 6-axis force/moment sensor for an intelligent robot's foot. In order to walk on uneven terrain safely, the foot should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz to itself. The applied forces and moments should be measured from a 6-axis force/moment sensor attached to a humanoid robot's foot(ankle). They in the published paper already have some disadvantage in the size of the sensor, the rated output and so on. The rated output of each component sensor (6-axis force/moment sensor) is very important to design the 6-axis force/moment sensor for precision measurement. Therefore, each sensor should be designed to be gotten similar the rated output under each rated load. So, the sensing elements of the 6-axis force/moment sensor should get lots of design variables. Also, the size of 6- axis force/moment sensor is very important for mounting to robot's foot. In this paper, a 6-axis force/moment sensor for perceiving forces and moments in a humanoid robot's foot was developed using many PPBs (parallel plate-beams). The structure of the sensor was newly modeled, and the sensing elements (plate-beams) of the sensor were designed using FEM (Finite Element Method) analysis. Then, the 6-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements, and the characteristic test of the developed sensor was carried out. The rated outputs from FEM analysis agree well with that from the characteristic test.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.7 s.196
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• pp.90-97
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• 2007

This paper describes the development of 6-axis force/moment sensor considered adult weight far an intelligent foot of humanoid robot. In order to walk on uneven terrain safely, the foot should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz to itself and control the foot using the forces and moments. The applied forces and moments should be measured from a 6-axis force/moment sensor attached to the foot, which is composed of Fx sensor, Fy sensor, Fz sensor, Mx sensor, My sensor and Mz sensor in a body. Each sensor should get the deferent rated load, because the applied forces and moments to foot in walking are deferent. Therefore, one of the important things in the sensor is to design each sensor with the deferent rated load and the same rated output. In this paper, a 6-axis force/moment sensor (rated load of Fx and Fy are 500Nm and Fz sensor is 1000N, and those of Mx and My are 18Nm, Mz sensor is 8Nm) for perceiving forces and moments in a humanoid robot's foot was developed using many PPBs (parallel plate-beams). The structure of the sensor was newly modeled, and the sensing elements (plate-beams) of the sensor were designed using by ANSYS software (FEM (Finite Element Method) program). Then, a 6-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements, and the characteristic test of the developed sensor was carried out. The rated outputs from FEM analysis agree well with that from the characteristic test.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.250-258
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• 1999

This paper presents a decentralized adaptive controller design for a Magnetically Levitated Fine Manipulator to follow the given trajectory as close as possible in spite of coupling effects between motion axes(degree of freedoms or subsystems). The present controller consists of two parts: the model reference controls based on known subsystems and the local adaptive controls. The former stabilizes the motion of the manipulator so as to follow that of the reference model. The latter reduces tracking errors due to coupling disturbances by adjusting the local gains to such levels that override interactions and assure the stability of the overall system. Through several experimental results, it has been shown that the decentralized adaptive control scheme has better tracking performances comparing to the PID controller case as well as good disturbance(coupling) rejection property.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.214-221
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• 2001

This paper describes the design of 3-component force/moment sensor with the force and moment ratio of wide range. It can measure the x-direction force Fx, y-direction force Fy and z-direction moment Mz simultaneously. In order to accurately measure forces and moment using 3-component force/moment sensor, it should get suitable force and moment ratio(the ratio of force Fx=200 N and moment Mz=20 Nm is ten to one), and small interference error. In this paper, in order to design the 3-component force/moment sensor with the force and moment ratio of wide range, the procedures are performed as follow : 1) the derivation of the equations to predict the bending strains on the surfaces of the plate-beams under the force or the moments, 2) the determination of the size of the sensing elements of the force/moment sensor by using the derived equations, 3) the Finite Element Method(FEM) analysis and the characteristic test for confirming the strains from the theory analysis, 4) the selection of the attachment locations of the strain gages of each sensor, 5) the analysis of the rated strain and the interference error at the attachment location of strain gages. It reveals that the rated strains calculated from the derived equations make a good agreement with the results from the Finite Element Method analysis and the characteristic test.