Abstract: Force sensor has been used as requisite for knowing information on the amount and the directions of forces on the skin surface. We have developed a four-degrees-of-freedom capacitive force sensor (approximately 20×20×5 mm3) that has a flexible structure and sixteen parallel plate capacitors. An iterative algorithm was developed for estimating four displacements from the sixteen capacitances using fourth-order polynomial approximation of characteristics between capacitance and displacement. The estimation results from measured capacitances had large error caused by deterioration of the characteristics. In this study, effective capacitors had major information were selected on the basis of the capacitance change range and the characteristic shape. Maximum errors in calibration and non-calibration points were 25%and 6.8%.However the maximum error was larger than desired value, the smallness of averaged value indicated the occurrence of a few large error points. On the other hand, error in non-calibration point was within desired value.
Abstract: In order to make environmental test centrifuge balance
automatically and accurately, reduce unbalance centrifugal force,
balance adjusting system of centrifuge is designed. The new balance
adjusting system comprises motor-reducer, timing belt, screw pair,
slider-guideway and four rocker force sensors. According to
information obtained by the four rocker force sensors, unbalanced
value at both ends of the big arm is computed and heavy block is
moved to achieve balance adjusting. In this paper, motor power and
torque to move the heavy block is calculated. In full load running
progress of centrifuge, the stress-strain of screw pair composed by
adjusting nut and big arm are analyzed. A successful application of the
balance adjusting system is also put forwarded. The results show that
the balance adjusting system can satisfy balance require of
environmental test centrifuge.
Abstract: The hand is one of the essential parts of the body for
carrying out Activities of Daily Living (ADLs). Individuals use their
hands and fingers in everyday activities in the both the workplace
and home. Hand-intensive tasks require diverse and sometimes
extreme levels of exertion, depending on the action, movement or
manipulation involved. The authors have undertaken several studies
looking at grip choice and comfort. It is hoped that in providing
improved understanding of discomfort during ADLs this will aid in
the design of consumer products.
Previous work by the authors outlined a methodology for
calculating pain frequency and pain level for a range of tasks. From
an online survey undertaken by the authors with regards
manipulating objects during everyday tasks, tasks involving
gripping were seen to produce the highest levels of pain and
discomfort. Questioning of the participants showed that cleaning
tasks were seen to be ADL's that produced the highest levels of
discomfort, with women feeling higher levels of discomfort than
men.
This paper looks at the methodology for calculating pain
frequency and pain level with particular regards to gripping
activities. This methodology shows that activities such as mopping,
sweeping and hoovering shows the highest numbers of pain
frequency and pain level at 3112.5 frequency per month while the
pain level per person doing this action was 0.78.The study then uses
thin-film force sensors to analyze the force distribution in the hand
whilst hoovering and compares this for differing grip styles and
genders. Women were seen to have more of their hand under a
higher pressure than men when undertaking hoovering. This
suggests that women may feel greater discomfort than men since
their hand is at a higher pressure more of the time.