Nanoforce sensing

At micro/nanoscale force sensing remains an important challenge to understand and to interact with this environment. In fact, forces sensing or force measurement is a key function in micro/nanomanipulation, in assembly systems or in micro/nanoscale probing. For example in biology, the contractile forces in the mN range from isolated ventricular heart cells (cardiac myocytes) differs in normal or diseased heart. In nanotechnologies, measurement of adhesion forces is required for experimental validation of different models for micro objects interactions, like model of adhesion. In micro/nanoscale manipulation, the interaction forces affect greatly gripping and assembly strategies. 

To deals with this limitation, force based control appears an appropriate solution to give helpful information for complex assembly tasks. For that, classical controllers that involve the force sensing between the gripper and the manipulated object are proposed. For exemple, H infinity controller was successfully used to design an active force sensor shown in Fig.1. This sensor was demonstrated by measuring the interaction of a water droplet with a glass probe (Fig.2) and the attractive magnetic forces (Fig.3).

Figure 1 : Active micro force sensor using H infinity controller. 

 

       Figure 2 : Interaction force probe/water droplet.                  Figure 3 : Magnetic force sensing.

In the context of REMIQUA, the H-infinity method will be validated with a specific load cell developed by REMIQUA partner CSEM. As a consequence, force sensing will give helpful information for performing tasks at micro/nanoscales. It will allow also to determine the assembly stiffness and maximum strength respectively through non-destructive and destructive tests in the specific case of REMIQUA project. In addition, the force based control could be an appropriate solution to guide the tool toward the objects and to master forces when gripping or assembling small objects.