Integrated Curvature Sensing of Soft Bending Actuators Using Inertial Measurement Units

We introduce a sensor concept for an integrated measurement of the curvature angle of soft bending actuators using inertial measurement units (IMUs). In particular, IMUs are placed at both ends of the soft bending actuator, and the integrated magnetic sensors are used for small and the integrated acceleration sensors for medium and large inclination angles of the soft actuator’s bending plane. The experimental results show absolute measurement errors of up to 20° for small and less than 5° for medium and large inclination angles. Furthermore, we investigate experimentally whether the assumption of a constant curvature in our sensor concept is still fulfilled when the soft bending actuator is loaded by an external force at its free end. The results indicate that this is the case for loading masses of up to 30 g at large inclination angles.