Fold Sensing Origami Gestures—A Case Study with Kresling Kinematics

Abstract

Abstract We extend previous work in the field of origami robotics by exploring the question of fold sensing. Fold sensing is the process of sensing the angle between two adjacent folding planes and can be used to approximate an origami structure as it folds and unfolds. Our work shows that capacitive sensing can be used to detect four distinct types of interactions from the same sensor data stream. Our capacitive fold sensing design can detect touch as a Boolean state, pressure as a scalar value, single-fold gestures as a scalar value measured between two panels, and multi-fold gestures as a multi-dimensional vector, comprised of single-fold values. Our case study considers single and multi-fold gestures for the unique origami kinematics of the Kresling-ori. We present a prototype fold sensing instrument and two digital twins. The unique folding kinematics of the Kresling-ori has distinct folding gestures such as compression, rotation, twisting, and bending, making it ideal for this case study. We detail our methods for translating sensor data into gestural data for each type. We include a partial characterisation of the sensor design, sensor calibration process, single-fold and multi-fold gesture recognition methods. Our study points to further work towards a generalised model for sensing the complex kinematic structures in origami, in rigid and flexible origami structures.