Feedback Control for Inflatable Soft Robotic Finger Touch Detection Based on Static Pressure-Resistance Characteristics

We present a method for feedback controlling a soft finger actuator and detecting "touch", i.e., contact with an object in the environment. While this work uses our pneumatic elastomeric actuator with a soft bending sensitive resistive sensor along its dorsal surface, the method is suited for many soft actuator designs with a bending sensor. We use a closed-loop reference tracking controller and detect contact from the magnitude of the reference tracking error. This method uses a single bending sensitive sensor and does not require a force sensor collocated with the point of contact. We demonstrate the method's ability to track a reference, sense and maintain contact with an external object, switch from a state of unimpeded motion to either a state of light touch or to a state of firm touch, and remain robust against orientation and saturation.