Ultrasound-based proximity sensors for human-machine interaction

Intelligent interactive systems for human-machine interaction (MMI) are increasingly being used in many applications in the areas of Industry 4.0, Smart Health, Smart Security and Automotive. Here, sensor systems for non-verbal information exchange in the near-distance and contact range are essential for both functionality and security. In order to meet the increasing demands in terms of performance, energy efficiency and functionality, researchers at Fraunhofer EMFT are working together with three other Fraunhofer institutes to develop a modularized MEMS technology and sensor platform.

measurement setup for an eight-channel ultrasonic transceiver chip
© Fraunhofer EMFT / Bernd Müller
measurement setup for an eight-channel ultrasonic transceiver chip

The approaches used to date for monitoring surfaces and objects are based on individual solutions of tactile or proximity sensors with different physical operating principles. In each case, capacitive methods and ultrasound-based methods have proven to be the most suitable. Current drivers of sensor development are the acquisition of a high multimodal information density by means of miniaturized sensors and the real-time response of the overall system for use in robotics, prosthetics and the consumer market. Here, technical reproduction of the human hand and the flexible gripping processes ("reactive gripping") that are possible with it are key competencies for the manufacturing industry and medical technology. However, MMI requirements for energy-efficient three-dimensional sensing with increasing lateral (< 700 μm) and axial (< 1 mm) resolution as well as fast signal utilization (> 20 Hz) cannot be mapped with currently available solutions.

Test board for ultrasonic based sensor
© Fraunhofer EMFT/ Bernd Müller
Test board for an eight-channel ultrasonic transceiver chip.
© Fraunhofer EMFT
16 channel evaluation board

The project ProtaktilUS addresses these growing market requirements in the field of tactile proximity sensing, providing an innovative modularized MEMS technology and sensor plat-form for a new business area within the Fraunhofer-Gesellschaft. Fraunhofer EMFT researchers are working with the Fraunhofer Institutes IPMS, IKTS and IFF on the first chip integration of high-resolution capacitive and ultrasound-generating elements on the CMOS-compatible platform. As part of this project, a demonstrator is being developed for the use case of reactive gripping in robotics for the handling and identification of objects with different properties.

This innovation of the developed module platforms MEMS, electronics and signal processing is expected to pave the way to further fields of application in industry, medicine, consumer prod-ucts and safety in the future.

The project is funded under Fraunhofer’s internal MAVO program.



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