Interaction force estimation during manipulation of microparticles

This work investigates the utilization of microparticles for the wireless sensing of interaction forces in magnetic-based manipulation systems. The proposed force estimation approach allows for using microparticles in sensing the interaction forces at hard-to-reach regions to avoid the mechanical and electronic complexities associated with physical force sensors. Based on the velocity of the microparticle and the applied currents at each of the electromagnets of the magnetic system, an interaction force observer is designed to estimate the contact forces between the microparticle and a soft-tissue simulant with different elasticities. Experimentally, a magnetic system is utilized to steer a microparticle towards a soft-tissue simulant to carry out force sensing. The experimental results show that forces in the range of nano-Newton can be estimated without nano-force sensors. The estimated interaction forces due to this contact can be used either in sensing and diagnosis applications, or in the realization of a force control system.