A new method for extending the range of conductive polymer sensors for contact force

Abstract This paper describes a technique for extending the force range of thin conductive polymer force sensors used for measuring contact force. These sensors are conventionally used for measuring force by changing electrical resistance when they are compressed. The new method involves measuring change in electrical resistance when the flexible sensor, which is sensitive to both compression and bending, is sandwiched between two layers of spring steel, and the structure is supported on a thin metal ring. When external force is applied, the stiffened sensor inside the spring steel is deformed within the annular center of the ring, causing the sensor to bend in proportion to the applied force. This method effectively increases the usable force range, while adding little in the way of thickness and weight. Average error for loads between 10 N and 100 N was 2.2 N (SD = 1.7) for a conventional conductive polymer sensor, and 0.9 N (SD = 0.4) using the new approach. Although this method permits measurement of greater loads with an error less than 1 N, it is limited since the modified sensor is insensitive to loads less than 5 N. These modified sensors are nevertheless useful for directly measuring normal force applied against handles and tools and other situations involving forceful manual work activities, such as grasp, push, pull, or press that could not otherwise be measured in actual work situations. Relevance to industry Force measurement instruments are important for providing ergonomics practitioners with a quantitative means for assessing the magnitude of physical stress associated with a particular operation, and for measuring the reduction in force associated with an ergonomic intervention

Use of computer aided drafting for analysis and control of posture in manual work

Computer aided design (CAD) in conjunction with digitised anthropometric manikins can be used for analysis and control of stressful work postures, one of the most frequently cited occupational risk factors of upper extremity cumulative trauma disorders. This paper describes the use of macros for manipulating manikins and workstation components and for designing the workplace. AutoCAD, a popular computer aided design software package, was used to demonstrate the feasibility of these concepts. Specifically, macros are used for drawing work equipment using parametric designs, manipulating manikins and analysing jobs. In comparing the macros to the use of primitive CAD commands, the macros not only decrease the amount of time needed to create workstation components, but they also make the task easier for the user and decrease the risk of errors. Despite the limitation of anthropometric data and manikins, CAD is an effective method for identifying postural stresses and redesigning the workstation to control the identified stresses.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28529/1/0000326.pd

Technique for extraction and mounting of gastropod radulae

Volume: 12Start Page: 143End Page: 14

A SYSTEMATIC NOTE ON OCENEBRA-BOULSONI

Volume: 15Start Page: 35End Page: 3

New taxa of western Atlantic Columbellidae (Gastropoda, Prosobranchia)

Volume: 81Start Page: 143End Page: 14

A New Mitrid From The Western Atlantic

Volume: 17Start Page: 95End Page: 9

Patterns Of Larval Development In Stenoglossan Gastropods

Volume: 17Start Page: 107End Page: 11