Anthropomorphic tactile sensors for tactile feedback systems

The reproduction of the human tactile sense is highly desirable for successful telemanipulation of irregularly shaped objects. Advanced tactile feedback systems could significantly simplify manipulation tasks in the macro domain (e.g. telerobotics) as well as in the micro domain (e.g. minimal-invasive surgery). In order to realize tactile feedback systems, there is an increasing interest in sophisticated tactile sensing systems capable of detecting and processing mechanical and non-mechanical contact parameters, like normal and shear contact forces, temperature, and, for the purpose of the self protection of the System, reproducing a sensation similar to mechanical and thermal caused pain in human. Because of the necessity of the tactile sensor system to interact with human operators within the framework of a tactile feedback system, an anthropomorphic approach was chosen. Based on investigations, research, and mechanical modeling in the field of tactile reception mechanisms, conclusions regarding working principle, structure, number, arrangement, optimal placement and desired parameters as well as regarding the strategies of signal and information processing are drawn fur the purpose of a general design of a tactile sensing system. The realization of single sensor elements by microstructuring and microfabrication is investigated. The applicability of different transduction principles is discussed with the result that, having in mind the intended tasks, the state of the art in microsystems technology, and the requirements of assembly and packaging, capacitive and piezoresistive sensors are most promising for mechanical contact sensing. Design and technology of a simple capacitive/piezoresistive 3D contact force sensor element and of a more complex capacitive contact force sensing element are presented, their feasibility is demonstrated and their integration into a sensor system is discussed.