• Journal of Institute of Control, Robotics and Systems
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• v.16 no.9
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• pp.840-845
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• 2010

This paper proposes the method indirectly measuring the operating force of the end-effect tip of surgical robot instrument which conducts the surgical operation in the body on behalf of the surgeon's hand. Due to the size and safety obligation to the surgical robot instrument, it is difficult to measure the operation force of its tip like grasping force. However the instrument is driven by cable-pulley torque transmission mechanism and when some force is occurred at the tip, then the reaction force appears on the cable as additional tension. Based on this phenomenon, this paper proposes a method to estimate the operating force from measuring reaction force against the driving motor by using a loadcell. And it induces mathematical equation to calculate the force from loadcell by approaching the modulus of elasticity to high order polynomial. And this paper proves the validity of proposed mechanism by experimental test.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.3
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• pp.21-27
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• 2021

PURPOSE: This study examined the relationship between the severity of a hallux valgus (HV) deformity and the kinetic three-dimensional ground reaction force (GRF) through a motion analysis system with force platforms in individuals with a HV deformity during normal speed walking. METHODS: The participants were 36 adults with a HV deformity. The participants were asked to walk on a 6 m walkway with 40 infrared reflective markers attached to their pelvic and lower extremities. A camera capture system and two force platforms were used to collect kinetic data during gait. A Vicon Nexus and Visual3D motion analysis software were used to calculate the kinetic GRF data. RESULTS: This research showed that the anterior maximal force that occurred in the terminal stance phase during gait had a negative correlation with the HV angle (r = -.762, p < .01). In addition, the HV angle showed a low negative correlation with the second vertical maximal force (r = .346, p < .05) and a moderate positive correlation with the late medial maximal force (r = .641, p < .01). CONCLUSION: A more severe HV deformity results in greater abnormal translation of the plantar pressure and a significantly reduced pressure force under the first metatarsophalangeal joint.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.169-176
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• 1998

A method for the dynamic analysis of multibody systems undertaking impulsive force is introduced in this paper. A partial velocity matrix based on Kane's method is introduced to reduce the number of equations to be solved. Only minimum number of equations of motion can be obtained by using the partial velocity matrix. This reduces the computational effort significantly to obtain the dynamic response of the system. At the very moment of the impulse, instead of using the numerical integrator to solve the equations of motion, the impulse and momentum principle is used to obtain the dynamic response. The impulse as wall as the reaction force acting on the kinematic joints can easily calculated too.

• Journal of Power System Engineering
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• v.20 no.3
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• pp.57-63
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• 2016

This paper presents the experimental result and theoretical analysis result to investigate the correlation between the operating force, angle and locking torque for vehicle hood frame. Also, we derived the experimental equation that using the results for experiment and theory. The hood frame is switching-devices used for opening and closing the vehicle hood. It needs the correlation data between locking torques of each joint, operating force and angle of hood frame. The correlation data for torque and reaction force of hood frame obtained through experiment and theory analysis. Finally, the experimental equation of the locking torque prediction for the hood frame is derived.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.383-392
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• 2018

This study investigated the change of additional axial stress of rail and reaction force at bridge bearings due to the track-bridge interaction when laying CWR on non-ballasted railway bridges including truss bridges with relatively long span. According to the results of the present study, additional axial stresses of rail and reaction forces at bridge bearings showed a large increase when CWR is installed on the non-ballasted railway bridge. The additional axial stress of rail can be acceptable if sufficient lateral resistance can be obtained. However, if the reaction force increases, there is a risk of damage of the bearing or pier, and therefore, it is necessary to take measures to mitigate the reaction force. It is found that additional axial stress of rail decreases when considering the frictional resistance of the bridge movable support, but its effect on the bearing reaction force is very small. On the other hand, when the longitudinal track restraint decreases, both additional axial stress of rail and bearing reaction force are reduced to a large extent. Also, when the ZLR fastening devices are applied to the region where the additional axial stress of rail is highest, bearing reaction force as well as additional axial stress of rail greatly decreased. Therefore, the application of ZLR fastening devices with the reduction of the longitudinal track restraints is very effective for installing CWR on non-ballasted railway bridges.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.7
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• pp.641-646
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• 2011

A low cost gait analysis system, which can measure stride length, walking speed, and ground reaction force, is proposed. A gait analysis system is used for medical evaluation of patients and rehabilitation assistance. Low cost cameras are attached to a shoe and movement of a shoe is estimated using infrared LED landmarks. Ground reaction force is measured from pressure sensors, which are installed inside a shoe. Through experiments, it is shown that the proposed system can be used to obtain stride length, walking speed, and ground reaction force.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.10
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• pp.929-934
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• 2014

Reaction force compensation (RFC) mechanism can relieve the vibration of base system caused by acceleration and deceleration of mover. In this paper, we propose a new passive RFC mechanism with a movable additional mass to reduce vibration of the system base as well as displacement of the magnet track. First, equation of motion for the new passive RFC mechanism is derived and simulated to tune design parameters such as masses and spring coefficients. Simulation results show that the vibration of the system base of the stage with the new RFC mechanism.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.7-12
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• 2011

Hydraulic excavator in digging at the construction machinery is a widely used mechanical device. Excavator attachments are taken with structural load and fatigue during digging under applied reaction. Fatigue analysis is done at joint pin between bucket and arm of front attachment at excavator under the force of hydraulic cylinder in operation. It is analyzed how load can be supported at the lower driving body applied on the bucket. In this study, the deformation of arm and the fatigue result are examined when reaction force is applied on the attachment of excavator.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.5
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• pp.554-562
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• 2015

This paper describes an analysis of an architecture and control system of a firefighting cannon manipulator (FCM) composed of two joint axes and one water-shooting actuator. Because the orienting FCM motion is disturbed by the reaction force from water shooting, the water shooting force has been modeled for robust control. The dynamics model of the manipulator has been set up including the external force of water-shooting reaction on the manipulator. A PD Controller and Sliding Mode Controller have been designed and their performance been tested through simulation to track a desired trajectory under the disturbance of a water-shooting reaction. The simulation shows that the performance of the Sliding Mode Controller is better than that of the PD controller.

• Journal of the Ergonomics Society of Korea
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• v.11 no.1
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• pp.93-101
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• 1992

Gait parameters for the Korean normal adults were compared with sex and age. Time-distance measurements and ground reaction force parameters were studied in relation to walking speed. Regression analysis was performed to establish functional relations between walking speed and various gait parameters. It is found that cardence and stride length varied linearly with walking velocity whereas time of double support was inversely proportional to walking velocity. The amplitude of ground reaction force was increased with increasing velocities of gait due to the greater heel-strike force and toe-off forces associated with these higher velocities. The results of this study can be usefull utilized as basic data to design and evaluate prosthetic devices, and to detect abnormal gait performances.