Distributed-force recovery for a planar photoelastic tactile sensor

In this paper, an efficient force-recovery algorithm is presented for a novel planar photoelastic tactile transducer. A distributed-force profile input to the tactile sensor developed in our laboratory generates stress in the photoelastic layer of the transducer, making it birefringent. Circularly polarized light input to the transducer is elliptically polarized at the output due to phase-lead created in the stressed photoelastic layer. The algorithm presented recovers the phase-lead distribution and correlates it to the input force profile. Since this distribution is a linear function of the force profile, the solution of the inverse-tactile problem is significantly simplified. The paper presents the analytical basis of the algorithm as well as the numerical technique used in its solution