Techniques for the evaluation of haptic interactions

Haptics, an area which deals with systems that use the sense of touch, is becoming more and more important through the years and now it is not just a field of theoretical research but has many practical applications in use. Although the applications and types of haptic interfaces are diverse, it is not very clear how to choose a specific haptic device for a particular task due to lack of comparable metrics between these systems. There are many efforts and studies in creating and developing hardware and software for haptic systems, but it seems there exist relatively few techniques for evaluation of them. In this thesis, we explore and present the proposed methods in the literature for evaluating haptic interfaces. Some of these studies evaluate only hardware, whereas some others employ methods in evaluating performance of different haptic rendering algorithms and yet others focus on user experience like the mental and physical demand, time load and frustration level. They also differ in methodology and perspective while evaluating these aspects. We first analyze and classify the different techniques that have been used in the evaluations of haptic systems. We then describe existing techniques for each class by explaining methods and performance measures used in the studies. The field of these studies and their applicability to different devices and conditions are also examined. Results of our analysis are collected into a single table which provides an overall view of all investigated techniques and facilitates choosing a specific one while doing an evaluation test on a particular haptic system. Gaps and problems in existing techniques are also discussed. We provide possible solutions to these gaps and some suggestions on how to approach a haptic system evaluation depending on the needs. There are also some efforts in setting the standards for haptic and tactile interactions. These works are mostly done by ISO (International Organization for Standardization) and a working group is in progress towards creating a standard as part of ISO 9241-900 series. Since we believe standards are indispensable also in evaluation, we give an overview of the current work done by ISO. Our survey and suggestions may help in comparing different haptic systems or their elements for a particular task or in improving performance while developing hardware.