Algorithms for processing data from a photoelastic slip sensor

Hopkins, S. H.; Eghtedari, F.; Pham, Duc Truong

doi:10.1016/0957-4158(92)90035-m

Cited by 10 publications

(1 citation statement)

References 6 publications

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“…The investigation of optical sensors as slip sensors initiated during late 80s. Hopkins and collaborators [108] suggested that macropixels, i.e. groups of single pixels captured with RAM cameras, were able to reduce computational times, storage memory required and noise (given the filtering effect of averaging many pixels).…”

Section: A Opticsmentioning

confidence: 99%

Methods and Sensors for Slip Detection in Robotics: A Survey

Romeo

Zollo

2020

IEEE Access

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The perception of slip is one of the distinctive abilities of human tactile sensing. The sense of touch allows recognizing a wide set of properties of a grasped object, such as shape, weight and dimension. Based on such properties, the applied force can be accordingly regulated avoiding slip of the grasped object. Despite the great importance of tactile sensing for humans, mechatronic hands (robotic manipulators, prosthetic hands etc.) are rarely endowed with tactile feedback. The necessity to grasp objects relying on robust slip prevention algorithms is not yet corresponded in existing artificial manipulators, which are relegated to structured environments then. Numerous approaches regarding the problem of slip detection and correction have been developed especially in the last decade, resorting to a number of sensor typologies. However, no impact on the industrial market has been achieved. This paper reviews the sensors and methods so far proposed for slip prevention in artificial tactile perception, starting from more classical techniques until the latest solutions tested on robotic systems. The strengths and weaknesses of each described technique are discussed, also in relation to the sensing technologies employed. The result is a summary exploring the whole state of art and providing a perspective towards the future research directions in the sector.

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Section: A Opticsmentioning

confidence: 99%

Methods and Sensors for Slip Detection in Robotics: A Survey

Romeo

Zollo

2020

IEEE Access

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Inverse analysis for the recovery of forces applied to photoelastic tactile transducers

et al. 1998

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In this paper, the forward and inverse analyses of one‐ and two‐layer photoelastic tactile transducers are presented. For such transducers, an applied force profile generates stresses in the photoelastic layer, making it birefringent. Consequently, circularly polarized light input to the transducer becomes elliptically polarized at the output because of the introduction of a phase‐lead distribution. Herein, the forward and inverse analyses of a one‐layer photoelastic tactile transducer, under ideal conditions, are first presented. The transducer is modeled using closed form equations based on the theories of elasticity and photoelasticity, which allow the calculation of the light intensity distribution corresponding to an applied force profile. However, to recover the force profile from a light intensity distribution (i.e., the inverse problem), the phase‐lead distribution must be determined first. A novel technique is described for this purpose. In the second part of the paper, we consider the forward and inverse analyses of a two‐layer transducer, under nonideal conditions, where the light‐intensity distribution is no longer noise‐free. In the forward analysis, the calculation of the stress distribution in the transducer is implemented by finite‐element analysis. The recovery of the phase‐lead distribution under noisy conditions, however, constitutes an ill‐posed inverse problem. A novel algorithm that accurately and effectively determines the phase‐lead distribution from a noisy light‐intensity distribution is presented. © 1998 John Wiley & Sons, Inc.

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