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Volume 28, Issue 2
Displaying 1-5 of 5 articles from this issue
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Osamu SUENAGA, Motozo IHARA1992 Volume 28 Issue 2 Pages 51-59
Published: April 15, 1992
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSA manual tracking control system is proposed by utilizing the design method of the model-following servo system, to aim at reducing the influence of the individual difference and keeping the control characteristics of the whole system constant independent of the human operator. We have proposed the manual tracking control system from the same points of view. But there are some problems on the realization of the plant-model, the task load for the human operator, etc., when the previous system is applied to the practical man-machine system. So, in this study, the improvement plans are examined, and the availabilities of the plans are confirmed experimentally. As the improvement plans, the model is set up so as to describe the desired control characteristics of the whole system in advance, and the reference signal is displayed directly for the human operator, taking account of the practical use. Furthermore, it is assumed that the plant input is composed of the manipulated variable by the human operator and the designed control input, which makes the plant output agree with the output of the model. As a result, the problems are improved, the new proposed system gives the satisfactory result for reducing the difference of the controlled variable (the plant output) depended on the human operator. But, there still remain some problems on the sense of operation for the proposed system.View full abstractDownload PDF (888K) -
Akihiro HOTTA, Matsutaro YOSHIOKA1992 Volume 28 Issue 2 Pages 61-68
Published: April 15, 1992
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSExperiments were conducted on 23 subjects using actual controllers in order to study direction-of-motion stereotypes for rotary control. The results of these experiments showed on the whole strong stereotypes for each control side with the exception of the bottom side, in the following relationships: 1) for the semi-circular indicator, when the rotating indicator (except the downward pointing semi-circular indicator) and the control were moved in the same direction, 2) for the geometric figure, when the control was moved clockwise in response to an indicator moving to the right, and counterclockwise in response to one moving to the left, 3) for the bar indicator when the control was moved clockwise in response to an upward pointing horizontal indicator sliding to the right, and counterclockwise in response to one sliding to the left; additionally, there were strong stereotypes for some left hand controls in response to an upward pointing vertical indicator moving downward. In these strong stereotypes positive reversibility were observed. On the other hand for controls located on the bottom side only one instance of strong stereotype and negative reversibility were found.View full abstractDownload PDF (5647K) -
Tetsuo TOKUDA, Keikol KODAMA1992 Volume 28 Issue 2 Pages 69-78
Published: April 15, 1992
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSTen kinds of model apparatus, each of which had a different function of testing pushpull strength and turning force, are set up in our laboratory to study correlations between the muscular strength and the operating method and/or the operating height. Peculiarities existing between the aged and the younger generation as well as characteristics common to them are clarified. The study is conducted on 12 elderly women (aged from 68 to 78) and 11 young women (aged from 19 to 21). The optimum height for manipulation varied according to the type of the apparatus and the results of the study show that the optimum height for manipulating the rotating apparatus is located approximately in halfway between the olecranon and the trochanter major. As for the scope of easiness in handling the apparatus, the elderly group show a narrower scope than the other. The maximum muscular strength is generated at the optimum height of the apparatus. And the muscular strength generated at each apparatus varied between the two groups.View full abstractDownload PDF (6071K) -
Kaoru FUJIIE, Kenji MITARAI, Tadao KOGA1992 Volume 28 Issue 2 Pages 79-89
Published: April 15, 1992
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSMeasurements were made of space, time and door-opening power necessary for a person with an injury to the spinal cord to pass through a doorway in a wheelchair. The subjects in this test were 23 people with various spinal cord injuries, and were classified by functional level from the lowest to the highest: C5A-C6A group (four quadriplegic persons with cervical cord injuries), C6B-C8 group (eight quadriplegic persons with cervical cord injuries) and T3-L1 group (eleven paraplegic persons with thoraco-lumbar cord injuries). Measurements were made of the time and position of the subject's wheelchair while passing through the doorway unit (sliding and hinged doors assembled in a laboratory) and of door-opening power.
The time necessary for passing through the door was longer for the C5A-C6A group than for other groups. The hinged door made passage possible in a shorter time than did the sliding door, but only when it was pushed open by the subject, not when it was pulled. The amount of space necessary for passage by the normal upper extremities group of paraplegics fitted most existing architectural guidelines for that group, but more space was needed for the quadriplegic group. The door-opening power was less for the C5A-C6A group than for other groups; with one subject, the least amount of power required for pulling, was about 500g in the case of a hinged door (equivalent to 1/20th of the power for the normal upper extremities group).View full abstractDownload PDF (8143K) -
Atsuo MURATA1992 Volume 28 Issue 2 Pages 91-98
Published: April 15, 1992
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSThe present paper deals with the measurement of mental workload by HRV (Heart Rate Variability) indexes. In the experimental task, subjects calculated the residue obtained by dividing 2-digit numbers by 3. The work levels (interstimulus intervals of the problems) were set up to 2, 3, 4 and 5 seconds. The ECG was continuously measured during the task. Concerning the error rate and the processing time, there were no significant differences among work levels. On the other hand, the mental workload value obtained by the method of paired comparison increased with the increase of the work level. The HRV measures DSDp and DSDn, which correspond to the standard deviation of the positive and negative differences between successive R-R intervals, were found to be effective indexes for the mental workload measurement. It was also found that the mental workload can be measured by TP which corresponds to the frequency of the relative maximal and minimal R-R intervals.View full abstractDownload PDF (1037K)
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