Microsystem locomotion is a key component for minimally invasive neurosurgical procedures. A self-propelling micro-robot facilitates targeted drug delivery, biopsy and neuro-stimulator positioning in brain parenchyma. In high frequency small deformation burrowing conditions, the soft brain tissue behaves as a viscoelastic fluidic environment and therefore Stokes swimmer techniques can be applied to move in the tissue. We use a piezoelectric vibrating bimorph bender in order to propel an electrode in the brain parenchyma. The vibrational motion of the beam is stimulated by a top piezoelectric layer, divided into three separately actuated segments. Flexural vibration is created by each segment by sinusoidal excitation. The frequency, amplitudes and phases combinations govern the total shape of the beam&s vibration. In order to discard the need for actuation modeling, we utilize the bottom piezoelectric layer of the bimorph for sensing. Three separated sensing segments convert the bending strain of the beam to electrical displacements and measured as voltages. By this measurement we are able to identify the frequency response (FR) of the beam vibration. We investigate the FR of a fully clamped commercially available piezoelectric bimorph in silicon oil. The implementation of the sensing abilities obtains maximal flow of the silicon oil, which indicates maximal propulsion forces. The suggested open loop control enables the systems identification of a swimming micro-robot in highly viscous fluids. Results were confirmed using particle image velocimetry (PIV) methods under a microscope camera.
