Additive Manufacturing of Deformable Sensing Devices for Human–Machine Interaction and Their Customization in the Layered Fabrication Space

Devices with sensing capabilities have become widespread. In the field of Human–Machine Interaction (HMI), they serve as communication channels between users and machines, allowing devices to detect and interpret human input. Traditionally, integrating sensing elements into 3D objects requires assembly processes. This research investigates how multi-material additive manufacturing (AM), using flexible, rigid, conductive, and insulating materials, enables the fabrication of deformable devices with embedded parametric capacitive sensors. The proposed sensor design is characterized and integrated into 3D models to create various HMI devices, such as buttons, a joystick, and a torque sensor. A method for estimating the force or torque applied to the sensor is also introduced. In addition, a computational fabrication method that enables the customization of sensing devices within the layered fabrication space is presented. This method applies per-layer transformations to adapt a template model to user-specific morphologies while preserving the performance of the integrated sensors. A staggered deposition strategy is also proposed to prevent unintended electrical connections. This work enables the fabrication of a custom-fit handle with sensing capabilities for mobility aids.