Recent advances in non-contact force sensors used for micro/nano manipulation

Abstract

Micro/nano manipulation for both mechanical and biological structures is currently a popular research field. To protect small-scale structures and acquire their mechanical properties, a micro-scale force sensor is needed. This paper focuses on reviewing the research on non-contact micro-force sensor parts that can be integrated in this manipulation system. The content involves the structure, working principle, resolution and sensitivity of different force sensor parts, including electrical and optical force sensors. The electrical force sensors include piezoresistive, piezoelectric, capacitive, electrothermal and strain gauge-based types; while the optical force sensors focus on but are not restricted to the optical fiber-based force sensors and the vision-based sensing systems. All of these sensors are analysed and compared. Electrical force sensors are currently widely used but are restricted by the sensing properties and size; optical force sensors have high sensitivity, small structure and anti-electromagnetic-interference properties, but they are hardly applied in micro/nano manipulation systems for force measurement. As a result, optical force sensors may become the new generation of sensors that can be integrated with micro/nano manipulation systems.