Fig 1.
Schematic representation of the energy conversion principle: the movement of the heart during a cardiac cycle (a) makes the unbalanced half-cylindrical weight oscillating (b) and induces an electric signal In the coil of the generator coupled to its rotation axis (c).
Fig 2.
Free body diagram of the harvesting system representing a section of the imbalanced weight.
The external force Fext, initiated by translational and rotational accelerations, causes an oscillation movement of the weight along the rotation axis (a). The mathematical model also takes into account the orientation of the pendulum compared to the horizontal XY-plane (b).
Fig 3.
The hexapod has six articulated arms that connect the motors with the end effector platform (a). The end effector platform holds the energy harvester that can be tilted to investigate the effect of different angles (b) (c) (d).
Table 1.
Characteristics of the In-vivo acquired trajectories reproduced by the hexapod.
Fig 4.
Cross-sectional view of the prototype (a). The prototype in its final 25 mm capsule form with a diameter of 6.8 mm (b).
Fig 5.
Results of the simulation (dashed line) in comparison to the output power measured during the experiment (continuous line) for 3 different weight length of respectively 8 (red), 16 (blue) and 32 (green) mm.
Fig 6.
Average output power in function of the heart rate for the animal (blue) and human (yellow) datasets for atrial (A) and ventricular (V) pacing location.
Fig 7.
Average output power in function of the angular orientation (see Fig 3) of the harvester for atrial paced heart motion (blue) and ventricularly paced heart motion (orange).
Fig 8.
X-ray image from of the energy harvesting prototype inside a porcine heart during the in-vivo experiment.
Panel (a) shows an antero-posterior view, panel (b) a right anterior oblique projection.
Fig 9.
Example of the output Voltage of the prototype (a) and the corresponding ECG (b) when measured during the in-vivo study. This signal was acquired during ventricular pacing at a rate of 160 bpm.
Table 2.
Average output power of the prototype measured during the in-vivo test.