Optimized Design Process for Haptic Systems by Systematic Consideration of Perception and Ergonomic Aspects

• Applicant: Dr.-Ing. Christian Hatzfeld
• Subject Area: Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics ; Human Factors, Ergonomics, Human-Machine Systems
• Term: from 2014 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 247646622

The aim of this work is the extension of the existing design methodology for haptic systems by a systematic consideration of ergonomic aspects and human perception in the design process. For this purpose, an interaction model for four common application areas of haptic systems (communications applications representation of virtual environments, non-invasive medical applications and telepresence systems) shall be developed. This model should allow derivation of suitable quality criteria for application-specific systems. To achieve this, the evaluation process is partitioned in the verification against the requirements and the validation of the intended function.Own work could identify haptic transparency as meaningful criterion to evaluate haptic feedback. It was extended to an optimization criterion that can be used in conjunction with other criterions like control stability in the design process. Thus, the verification of a system can be performed completely without user studies; these are only needed for the validation of the function of the system based on the above mentioned quality criteria. Thus, the development process is reduced in time.Basis for this evaluation methodology are specifically derived requirements of the system, an accurate description of the user and the intended human-system interaction. Based on preliminary work of the applicant, the mechanical impedance of the user and the absolute and differential thresholds of perception of the user are identified as relevant parameters to describe the user in the design process. It is therefore intended to design a measuring system for determining the mechanical impedance and relevant user perception characteristics. The control scheme of the system is based on kinematic variables, as these allow smaller scatter and a higher precision of the results. A further increase in efficiency can be expected by the selection of a suitable psychometric method. This can also be based on previous work of the applicant.Since the perception of forces and kinematic variables is linked by the mechanical impedance, influence parameters on the mechanical impedance of the user will be analyzed an user study using the developed measurement system. The aim is the identification of external variables which have an influence on the mechanical impedance and, therefore, on human perceptual abilities.The identified parameters of influence are to be treated so that they can be used by developers to optimize task-specific haptic systems. Thus, for example certain grip configurations or defined minimum contact forces possibly bring forth a change in impedance, causing lower sensitivity of the user and thus lowering system requirements.The results of the project will be published in a new edition of the book "Engineering Haptic Devices", Springer. The applicant is one of the editors of the book.

• DFG Programme: Research Grants
• Participating Person: Professor Dr.-Ing. Roland Werthschützky