A Haptic Training Simulation for Paper Conservation: Preliminary Results

Abstract. This paper presents the preliminary development and testing of a prototype haptic simulation environment for skilled manual tasks applied in the field of paper conservation. The procedure of backing removal involves
the gradual removal by scalpel of aged and degraded card backing materials, adhered to fragile works of art on paper. A backing removal simulation was developed for the Reachin® display system by extending the existing API class library in C++. The simulation environment and interface was created using VRML and Python. It is intended that the prototype be developed as a training tool for conservation education, allowing students to develop manual skills in the virtual environment prior to treating valuable works of art. Initial tests were conducted with a group of randomly selected, novice conservation students to establish if learning and skill development takes place in the context of repeated simulation training sessions.

The research investigated the efficacy and implementation of touch-interactive (haptic) virtual simulation training for conservation practice. Such training methods, although already being developed for surgeons, had not been investigated in the context of conservation or other applied arts and this project was the first to advance the field in this domain.

Research in medicine had established methods primarily for the haptic modelling of elastic and viscoelastic tissue. However, prior to the study little development had been done for the modelling of the complex plastic behaviour that is typical of materials found in conservation. The problems of achieving perceptually convincing modelling of complex multi-layered structures and of a facsimile virtual task were addressed. The material displacement of the virtual backing required the development of a novel software algorithm for haptic plastic deformation.

A method of gathering and processing force and the positional data from the “Phantom” simulation device and an experimental test application were developed. A series of quantitative skill indicators, such as peak force, were established and used to assess performance in the visual task. A group of 15 novice conservation students were selected to take part in the experimental study.

The outcome was produced after the development of a prototype environment and an extensive phase of field-testing and evaluation. The results of an investigation into skill acquisition in the virtual haptic environment confirmed fundamental validity of the use of simulation training in conservation by establishing that motor learning does take place in the simulation environment. Testing additionally revealed new information on novice learning trends and the advantages of haptic training, particularly in the very early stages of skill acquisition when excessive or ineffectual forces are most likely to occur.

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