We introduce a low-cost method for mounting sensors onto robot links for large-area sensing coverage that does not require the sensor's positions or orientations to be calibrated before use. Using computer aided design (CAD), a robot skin covering, or skin unit, can be procedurally generated to fit around a nondevelopable surface, a 3D surface that cannot be flattened into a 2D plane without distortion, of a robot. The skin unit embeds mounts for printed circuit boards of any size to keep sensors in fixed and known locations. We demonstrate our method by constructing point cloud images of obstacles within the proximity of a Franka Research 3 robot's operational environment using an array of time of flight (ToF) imagers mounted on a printed skin unit and attached to the robot arm.
Figures & tables
Fig. 1 : (Left) A diagram showing the procedure of digitally designing a skin unit to its deployment on a robot. A model of a sensor board and a robot model are inputted into the procedural mounting step where we use 3D graphics software to fit a skin cover around a specified link. (Right) A comparison of the point cloud representation of detected obstacles versus their position relative to the FR3 in real life. Different point colors represent depth measurements from different sensors. ”Far Wave” shows a person waving their hand approximately 14 cm away from the skin unit. ”Near Approach” shows a person putting their fist close to the skin unit. ”Close object” shows a roll of tape situated from the sensors at close proximity. In the point cloud reconstruction of the tape roll, the hollow center of the tape is clearly defined.
Fig. 2 : (a) Photo of the skin unit. For proximity sensing, we chose to mount time of flight (ToF) imagers. Each ToF imager is attached to an index (0-7) on the multiplexer. (b) General schematic of the electrical hardware.
Robots operating in dynamic and shared environments benefit from anticipating contact before it occurs. We present GenTact-Prox, a fully 3D-printed artificial skin that integrates tactile and proximity sensing for contact detection and anticipation. The artificial skin platform is modular in design, procedurally generated to fit any robot morphology, and can cover the whole body of a robot. The skin achieved detection ranges of up to 18 cm during evaluation. To characterize how robots perceive nearby space through this skin, we introduce a data-driven framework for mapping the Perisensory Space -- the body-centric volume of space around the robot where sensors provide actionable information for contact anticipation. We demonstrate this approach on a Franka Research 3 robot equipped with five GenTact-Prox units, enabling online object-aware operation and contact prediction.
Carson Kohlbrenner, Anna Soukhovei, Caleb Escobedo +2
All authors are with the Human Interaction and RObotics [HIRO] Group, University of Colorado Boulder, 1111 Engineering Drive, Boulder, CO USA.
Quadruped robots typically rely on depth cameras and LiDAR sensors to map their local environment. However, these sensors have limited close-range coverage, are relatively expensive, and consume significant power. This study investigates whether distributed Time-of-Flight (ToF) sensors can serve as a low-cost alternative to depth cameras for near-field terrain mapping for locomotion and local navigation. We designed a distributed ToF sensing architecture for the ANYbotics ANYmal quadruped, assessed its environment reconstruction accuracy, and benchmarked it against depth cameras for terrain mapping and obstacle avoidance. Distributing these sensors around the robot can also avoid the blind spots of traditional sensors. Our results show that, despite their low resolution and higher measurement noise, distributed ToF sensors can support reliable perceptual locomotion with centimeter-level local mapping accuracy. The proposed sensing strategy provides sufficient geometric information for near-field obstacle avoidance and footstep planning, at substantially lower cost, energy consumption, and system complexity than depth cameras.
3D-printed artificial skins are a scalable approach to whole-body tactile and proximity coverage, but prior implementations have been limited to unimodal sensing and rigid materials. To improve the practical usability of 3D-printed artificial skins, we present a hybrid time-of-flight (ToF) and self-capacitance (SC) sensing skin that demonstrates multi-modal sensing integration, soft compliant coverings for impact absorption and pressure sensing, and a streamlined electrical interface between printed conductive traces and external electronics. We show that combining ToF and SC modalities enables contact detection, scene reconstruction, and pressure-correlated tactile responses with the compliant covering by deploying six artificial skin units with 40 sensing elements over an FR3 robot arm.
Carson Kohlbrenner, Caleb Escobedo, Sayak Ray +5
Human Interaction and Robotics [HIRO] Group, University of Colorado Boulder, 1111 Engineering Drive, Boulder, CO USA.