• Physical Therapy Rehabilitation Science
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• 제12권2호
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• pp.130-139
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• 2023

Objective: This study aimed to analyze the effects and characteristics of the height of the treatment table on the force and time of ground reaction (GR) and contact hand (CH) generated from the therapist's feet to generate thrust during spinal manipulation (SM). Design: A cross-sectional survey study Methods: Thirty-six healthy subjects were recruited. SM was performed on the ilium using a knee-high table, where the therapist felt it was easy to control the subject's posture and body shape and comfortable to generate force, as well as a relatively high thigh-high table. The force and time generated by the therapist's GR and CH were simultaneously measured through a force plate. Results: As a result, there was a significant difference in peak force and rundown force at the therapist's GR according to the table height (p < 0.05). In the therapist's CH, there was a significant difference between PreMin (preload minimum) force and peak force (p < 0.05), and there was a significant difference between the time from PreMin to peak and the time of the entire section (p < 0.05). Conclusions: As a result, the generation of increased CH force and faster thrust duration were confirmed by mobilizing the reduced GR force of the therapist to generate thrust than the relatively high table on the knee-high table.

• 대한산업공학회지
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• 제30권2호
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• pp.165-174
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• 2004

It is known that one out of every ten people walking down the street is left-handed. In daily living, left-handed people come across hardwares and facilities that were designed for right-handed people. Most tools, utensils, office equipment, home appliances, clothes, medical instruments, sporting goods, weapons, and public facilities are made for the right-handed person. Many left-handed people thus have trouble with living in our environments. In this study, 1,933 Korean male and female subjects aging from 10 to 82 were selected to investigate the various statistics about hand dominance and their employment characteristics of preferred hand in handling diverse products and facilities. The statistics showed that 5.6% were left-handed and 7.6% were ambidexter. There were strong tendency that left-handed people use more left hand when take action that force is required than when take exquisite action. Ambidexter and right-handed people use more right hand when they take exquisite action is required than when take action that force is required. It was found from these results that people use their hands differently depending on the hand dominance when they handle things, hence this should be considered in designing hand control devices.

• 제어로봇시스템학회논문지
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• 제12권6호
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• pp.594-599
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• 2006

In this paper an anthropomorphic robot hand called SKKU Hand IIl is presented, which has a miniaturized fingertip tactile sensor. The thumb is designed as one part of the palm and multiplies the mobility of the palm. The fingertip tactile sensor, based on polyvinylidene fluoride (PVDF) and pressure variable resistor ink, is physically flexible enough to be deformed into any three-dimensional geometry. In order to detect incipient slip, a PVDF strip is arranged along the direction normal to the surface of the finger of the robot hand. Also, a thin flexible sensor to sense the static force as well as the contact location is fabricated into an arrayed type using pressure variable resistor ink. The driving circuits and the tactile sensing systems for the SKKU Hand II are embedded in the hand. Each driving circuit communicates with others using CAN protocol. SKKU Hand II is manufactured and its feasibility is validated through preliminary experiments.

• 대한인간공학회지
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• 제33권6호
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• pp.553-563
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• 2014

Objective: The purpose of this study was to evaluate the effect of gender (male, female) and grip spans (45, 50, 60, 70, 80mm) on total grip strength, resultant force, finger force and subjective discomfort rating. Background: In order to prevent musculoskeletal disorders, studies of hand tools need to be preceded based on grip strength, finger force, and subjective discomfort rating. However, experimental apparatus using tools such as pliers that reflect the actual work place was almost non-existent. Method: Fifty-Two (26 males and 26 females) participants were recruited from the student population. In this study, a pair of revised pliers, which can change grip span from 45 to 80mm was applied to estimate total grip strength, resultant force and individual finger forces. All participants were asked to exert a maximum grip force with three repetitions, and to report the subjective discomfort rating for five grip spans of pliers (45, 50, 60, 70, 80mm). Results: There were significant differences of total grip strength, resultant force, individual finger forces and subjective discomfort rating according to grip span. The lowest total grip strength was obtained from the grip span of 80mm for both genders. For resultant force, the highest resultant force was exerted at grip spans of 50, 60 and 70mm for females and 50 and 60mm for males. The lowest subjective discomfort rating was observed in the 50mm for both genders. Conclusion: Based on the result, 50mm and 60mm grip spans which provide the highest force and lowest discomfort rating might be recommendable for the male and female pliers users. Application: The findings of this study can provide guidelines on designing a hand tool to help to reduce hand-related musculoskeletal disorders and obtain better performance.

• 산업기술연구
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• 제28권A호
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• pp.155-161
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• 2008

Muscle force prediction in forward dynamic analysis of human motion depends many muscle parameters associated with muscle actuation. This research studies the effects of various parameters of Hill type muscle model using the simple hand raising motion. Motion analysis is carried out using motion capture system, and each muscle force is recorded for comparison with muscle model generated muscle force. Using Hill type muscle model, muscle force for generating the same hand rasing motion was setup adjusting 5 activation parameters. The test showed the importance of activation parameters on the accurate generation of muscle force.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2002년도 춘계학술대회
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• pp.31-36
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• 2002

In this paper, we developed a working adaptation evaluation system using finger force measurement which interact between material and biological system. The system consists of a finger force transducer, a signal conditioner, an A/D converter, a computer, and a software system for data processing. The finger force transducer is made by a load cell and a special mechanism. The data processing software controls the A/D converter, data monitoring, and data analysis for group classification. The developed system were tested by 4 different materials in left hand and the finger forte transducer in the other hand's thumb and index finger with 16 persons. As the results of experiments, the developed system could measure the finger force quantitatively and classify the measured values into four groups.

• 제어로봇시스템학회논문지
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• 제19권12호
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• pp.1138-1144
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• 2013

This paper proposes a tactile transfer and display method between a data glove and vibration motors module. The data glove is developed to capture the hand postures and to measure the grip forces. The measured data are simplified with the proposed 5-bit transfer and display algorithm, and the vibration motors module is developed to display the measured hand posture and grip force to the operator. The proposed 5-bit algorithm contains both an 8-step hand posture and 4-step grip force level information for tactile transfer to the vibration motors module. Also, the effectiveness of the proposed method is shown through several experiments.

• 대한인간공학회지
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• 제28권2호
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• pp.27-34
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• 2009

The purpose of this study was to evaluate aging (young and old), gender (male and female), and handle shape effects on grip force, finger force, and subjective comfort. Four handle shapes of A, D, I, and V were implemented by a multi-finger force measurement (MFFM) system which was developed to measure every finger force with different grip spans. Forty young (20 males and 20 females) and forty old (20 males and 20 females) subjects participated in twelve gripping tasks and rated their comfort for all handles using a 5-point scale. Grip forces were calculating by summation of all four forces of the index, middle, ring and little fingers. Results showed that young males (283.2N) had larger gripping force than old males (235.6N), while young females (151.4N) had lower force than old females (153.6N). Young subjects exerted the largest gripping force with D-shape due to large contribution of the index and middle fingers and the smallest with A-shape; however, old subjects exerted the largest with I-shape and the smallest with V-shape due to small contribution of the ring and little fingers. As expected, the middle finger had the largest finger force and the little finger had the smallest. The fraction of contribution of index and ring fingers to grip force differed among age groups. Interestingly, young subjects provided larger index finger force than ring finger force, whereas old subjects showed that larger ring finger forces than index finger force in the griping tasks. In the relationship between performance and subjective comfort, I-shape exerting the largest grip force had less comfort than D-shape producing the second largest grip force. The findings of this study can provide guidelines on designing hand tool handle to obtain better performance as well as users' comfort.

• 대한인간공학회지
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• 제19권2호
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• pp.75-86
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• 2000

In this study, the characteristics of transmitted vibration on HAS(hand-arm system) were identified to evaluate physical load due to the work surface orientation, tool weight and push force during powered drilling tasks. The characteristics of transmitted vibration on work surface orientation showed that the acceleration of transmitted vibration on horizontal work surface was higher than that on the vertical work surface. Regarding the characteristics of transmitted vibration on tool weight, the vibration acceleration level becomes lower as the tool weight becomes heavier. The amount of transmitted vibration on hand-arm system was decreased down to the tool weight of 2.4kg. However, as the tool weight becomes heavier than 2.8kg, the amount of transmitted vibration was increased and had peak value at 3.2kg of tool weight. Regarding the characteristics of transmitted vibration on push force, the vibration acceleration level goes higher, as the push force becomes larger. The characteristics of transmitted vibration on the axis of vibration showed that the direction of $Z_h$ had the highest acceleration compared to the direction of $X_h$, and $Y_h$. The direction of $X_h$, $Y_h$ and $Z_h$ had the highest acceleration of transmitted vibration on the hand, wrist and elbow, respectively. The results of this study showed that the condition which affect the lowest physical load to the subject on the powered drilling task would be working with the 2.4kg of tool weight on the vertical work surface.

• 한국운동역학회지
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• 제27권1호
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• pp.1-7
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• 2017

Objective: The purpose of this study was to analyze the relationship between ground reaction force (GRF) and attack time according to the position of hand segments during counter attack in Kendo. Method: The participants consisted of 10 kendo athletes (mean age: $21.50{\pm}1.95yr$, mean height: $175.58{\pm}5.02cm$, mean body weight: $70.96{\pm}9.47kg$) who performed standard head strikes (A) and counter attack with a preferred hand position of +10 cm (B), 0 cm (C), and -10 cm (D). One force-plate (AMTI-OR-7., USA) was used to collect GRF data at a sample rate of 1,000 Hz. The variables analyzed were the attack time, medial-lateral GRF, anterior-posterior GRF (AP GRF), peak vertical force (PVF), and loading rate. Results: The total attack time was shorter in types A and C than in types C and D. The AP GRF, PVF, and loading rate had significantly higher forces in types C and D than in types A and C. The attack time (bilateral and unilateral leg support and total) was positively correlated with the GRF variables (vertical GRF and loading rate) during the counter attack in Kendo (r = 0.779 [$R^2=0.607$], p < 0.001). Conclusion: The positions of the hand segments can be changed by various conditions of the opponent in Kendo competitions; however, the position preferred by an individual can promote the successful ratio of the counter attack.