We are seeing an increasing trend in the number of computing devices attached to the body which provide a myriad of data along with additional interaction mechanisms and haptic feedback from these locations. Although this provides more computing locations, the devices are still resigned to stay in those particular locations. We believe that relocatable wearables can reduce the number of devices that the user has to keep track of, while also providing dynamic data by moving around the body. Some attempts have been made to build relocatable wearables, but these attempts are either too bulky or make the use of unreliable and slow locomotion mechanisms.

In this thesis, we present Calico, a miniature wearable robot system with fast and precise locomotion for on-body sensing, actuation, and interaction. Calico consists of a two-wheel robot and an on-cloth track system or "railway," on which the robot travels. The robot packs an IMU, a battery and an onboard microcontroller that supports wireless BLE communication. The track system has multiple branches that extend to key areas of the human body, allowing the robot to reach the front and back of the torso, shoulders and arms, and even lower body areas such as legs. The track system also includes rotational switches, or "railway turntables," enabling complex routing options when diverging tracks are presented.

We introduce the system design of Calico and report a series of technical evaluations for system performance. To illustrate potential use cases, we present a suite of applications, including remote medical usage for chest auscultation, body posture tracking for training and exercise, a wearable walkie-talkie, and a robot companion living on-body.