| Budget Amount *help |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2005: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2004: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
This study was aimed to clarify the effect of delay appeared during force feedback generation in robotic manipulation in a minimally invasive treatment. A tactile expression in manipulator due to touch of the end-effecter of robot with patient was assumed.
Among various manipulations, push/pull operation which generates normal stress and sliding operation which generates shear stress were measured and analyzed. During a tactile expression process, delays due to calculation and data transfer will be appeared. Two types of tactile delay were assumed ;
(1) Continuous tactile response according with user action expressed after a constant time lag (called Communication-type delay).
(2) Tactile response according with user action expressed after a constant insensitive duration (called Calculation-type delay). A series of psycho-physical experiments two types of haptic operation under two patterns of haptic delay were done.
Increasing, decreasing and randomly changing a delay with 5 msec interval
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while the delay was under 100 ms and with 10 msec interval while over 100 msec, force-feedback were presented against a user's action. The experiment were performed to 15 students for normal stress and 12 students for shear stress, then the threshold of shortest delay which could be perceived as a delay or unnatural response.
In the experiment presenting only force-feedback, the threshold against normal stress were between 20 and 30 msec on Communication-type delay, and 5 msec on Calculation-type delay. Against shear stress, the threshold were between 55 and 60 msec for Communication-type delay, and between 45 to 50 msec for calculation-type delay. Delay perception against normal stress was sharper than shear stress.
Moreover, simultaneously presenting visual and tactile expression, a similar delay-perception threshold was measured. Animation synchronized with user's action and synchronized with delayed force-feedback were presented under two patterns of delay. The results were 80 to 85 msec for Communication-type delay, 60 to 65 msec for Calculation-type delay and 70 to 75 msec for Communication-type delay, 55 to 60 msec for Calculation-type delay for each. The results showed visual presentation made delay perception dull, and visual presentation without delay made delay perception duller.
Obtained results were expected to be applied in design for safe force-feedback medical equipment. Less
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