Novel Force Sensing Approach Employing Prismatic-Tip Optical Fiber Inside an Orthoplanar Spring Structure

This paper presents a novel approach to force sensing by integrating prismatic-tip optical fibers with an orthoplanar spring structure. The complete force sensing solution integrating the prismatic-tip-based sensing concept with an orthoplanar spring mechanism to convert applied forces into a well-delivered displacement whose magnitude can be measured using the optical sensing technique is introduced in this paper. To the best knowledge of the authors, this is the first time that such a force sensing concept has been proposed and studied. The compact force sensor prototype described in this paper demonstrates its capability and feasibility in performing force measurement over a range of 0-2.8 N. The combination of the novel concepts of prismatic-tip optical fiber sensing and the planar spring minimizes the thickness of the sensing device. Due to its simple sensing structure, the sensor is easy to manufacture and can be miniaturized for applications in dexterous robotic handling and the aerospace industry. The proposed sensor is made of nonmetallic materials and operates without the need of electronics components in the sensing area; thus, the sensor is not susceptible to electric or magnetic fields.