WiForce: Wireless Sensing and Localization of Contact Forces on a Space Continuum
This work addresses the need for richer force information, including magnitude and location, for human-computer interaction and human-robot interaction in tasks like surgery, where current digital interactions are limited to binary touch.
This paper introduces WiForce, a wireless sensor that can detect both the magnitude and location of contact forces. It achieves this by transducing force information into phase changes of an incident RF signal, which are then modulated into a backscattered signal. WiForce achieved a force accuracy of 0.3 N and a contact location accuracy of 0.6 mm.
Contact force is a natural way for humans to interact with the physical world around us. However, most of our interactions with the digital world are largely based on a simple binary sense of touch (contact or no contact). Similarly, when interacting with robots to perform complex tasks, such as surgery, richer force information that includes both magnitude and contact location is important for task performance. To address these challenges, we present the design and fabrication of WiForce which is a 'wireless' sensor, sentient to contact force magnitude and location. WiForce achieves this by transducing force magnitude and location, to phase changes of an incident RF signal of a backscattering tag. The phase changes are thus modulated into the backscattered RF signal, which enables measurement of force magnitude and contact location by inferring the phases of the reflected RF signal. WiForce's sensor is designed to support wide-band frequencies all the way up to 3 GHz. We evaluate the force sensing wirelessly in different environments, including through phantom tissue, and achieve force accuracy of 0.3 N and contact location accuracy of 0.6 mm.