Designing accurate and real time sensing systems for continuum robots is difficult because of their high degrees of freedom. This paper proposes a magnetic field sensing solution for 3-DoF pose estimation of soft continuum robots. We investigated our sensor inside an origami continuum robot, capable of 3-DoF constant curvature motion. Using motion capture, we validate our sensing solution in this system, and we measure sensing errors of less than 1.6mm. Our experiments also demonstrate the sensor’s accuracy during external object contact and unmodeled shape deformation. This application uses a custom high speed particle filter that runs in excess of 2 kHz, allowing this system to be applicable for real time feedback control of continuum robots.
Figure 1: Soft origami continuum robot with embedded magnet and Hall effect sensor for 3-DoF pose estimation.
Figure 2: Helical Path Experiment Position data collected from the helical path experiment. This plot shows the error of the filtered Hall-effect sensor and the internal encoders when compared to external motion capture readings.
Figure 3: Collision Detection Experiment Depicts the x, y, and z position of the continuum robot’s tip according to different measurements, along with the error in sensor and encoder measurements, as the robot followed an obstructed helical path.