FPGA-based Wideband Force Control System with Friction-Free and Noise-Free Force Observation

Force-assembly with friction

If an admittance control law is properly designed, a workpiece can be guided into a fixture using only the contact forces for guidance (force-assembly). Previously, we have shown that: 1) a space of accommodation control laws that will ensure force-assembly without friction always exists, and 2) as friction is increased, a control law that allows force-assembly can be obtained as long as the fo...

Reconstruction of Solar Coronal Linear Force-Free Magnetic Field

A semiempirical free energy force field with charge-based desolvation

The authors describe the development and testing of a semiempirical free energy force field for use in AutoDock4 and similar grid-based docking methods. The force field is based on a comprehensive thermodynamic model that allows incorporation of intramolecular energies into the predicted free energy of binding. It also incorporates a charge-based method for evaluation of desolvation designed to...

Electrostatic-free piezoresponse force microscopy

Contact and non-contact based atomic force microscopy (AFM) approaches have been extensively utilized to explore various nanoscale surface properties. In most AFM-based measurements, a concurrent electrostatic effect between the AFM tip/cantilever and sample surface can occur. This electrostatic effect often hinders accurate measurements. Thus, it is very important to quantify as well as remove...

Atomic-scale friction control by vibration using friction force microscope

Manipulation of friction at the nanoscale has been traditionally approached by chemical means (lubrication). Recent friction force microscopy (FFM) experiments demonstrated that it can be done mechanically by applying vibration to accessible elements of the system. This paper provides analytic understanding on why vibration can reduce friction based on a 1D model imitating the FFM tip moving on...