Optomechanical force estimation using passive micromanipulator end-effectors

This paper presents a vision-based force estimation strategy using compliant 3D-printed micromanipulative end-effectors. These passive tools, which introduce increased flexibility to the task, can also be used as integrated force sensors using vision-based tracking. The main contributions of the work include two main aspects. Firstly, an investigation into the effects of manufacturing parameters on the characteristics of the passive, spring component of the tool. This is conducted in order to establish trends in the tool's material properties based on different fabrication settings. It is shown that, using two photon polymerization (TPP), it is possible not only specify the geometry of the tool but also to further tune the mechanical properties using specific fabrication parameters. This allows for further customization of the tool to suit the particular task at hand. Secondly, the vision-based force estimation method demonstrates the bimanual transportation of a particle while trying to maintain a constant grip force. During the initial manual stage of the task, the haptic interface reflects forces to the user as they grasp the object. During the autonomous stage, transportation of the particle to a setpoint is carried out under closed-loop control while sustaining the force specified. The advantages and limitations of the approach are discussed, and potential avenues for future research are suggested.