Abstract: A method for imaging a sample using a high speed dynamic mode atomic force microscope may include scanning a tip of a cantilever probe over a surface of the sample, regulating a vibration amplitude of the tip to remain constant at a set point value (Aset), via a first signal generated in a first feedback controller, measuring a mean tapping deflection of the tip, regulating the mean tapping deflection via a second signal generated in a second feedback controller, tracking and measuring an adjustment to the measured mean tapping deflection during the regulating. The method may further include generating an image topography of the sample based on the first signal, the second signal, and the measured adjustment of the mean tapping deflection of the cantilever probe.

Abstract: A method for imaging a sample using a high speed dynamic mode atomic force microscope may include scanning a tip of a cantilever probe over a surface of the sample, regulating a vibration amplitude of the tip to remain constant at a set point value (Aset), via a first signal generated in a first feedback controller, measuring a mean tapping deflection of the tip, regulating the mean tapping deflection via a second signal generated in a second feedback controller, tracking and measuring an adjustment to the measured mean tapping deflection during the regulating. The method may further include generating an image topography of the sample based on the first signal, the second signal, and the measured adjustment of the mean tapping deflection of the cantilever probe.

Abstract: A control-based approach is provided for achieving accurate indentation quantification in broadband and in-liquid nanomechanical property measurements using atomic force microscope (AFM). Accurate indentation measurement is desirable for probe-based material property characterization because the force applied and the indentation generated are the fundamental physical variables that are measured in the characterization process. Large measurement errors, however, occur when the measurement frequency range becomes large (i.e., broadband), or the indentation is measured in liquid on soft materials. Such large measurement errors are generated due to the inability of the conventional method to account for the convolution of the instrument dynamics with the viscoelastic response of the soft sample when the measurement frequency becomes large, and the random-like thermal drift and the distributive hydrodynamic force effects when measuring the indentation in liquid.

Abstract: A control-based approach is provided for achieving accurate indentation quantification in broadband and in-liquid nanomechanical property measurements using atomic force microscope (AFM). Accurate indentation measurement is desirable for probe-based material property characterization because the force applied and the indentation generated are the fundamental physical variables that are measured in the characterization process. Large measurement errors, however, occur when the measurement frequency range becomes large (i.e., broadband), or the indentation is measured in liquid on soft materials. Such large measurement errors are generated due to the inability of the conventional method to account for the convolution of the instrument dynamics with the viscoelastic response of the soft sample when the measurement frequency becomes large, and the random-like thermal drift and the distributive hydrodynamic force effects when measuring the indentation in liquid.

Abstract: An optimal input design method and apparatus to achieve rapid broadband nanomechanical measurements of soft materials using the indentation-based method for the investigation of fast evolving phenomenon, such as the crystallization process of polymers, the nanomechanical measurement of live cell during cell movement, and force volume mapping of nonhomogeneous materials, are presented. The indentation-based nanomechanical measurement provides unique quantification of material properties at specified locations. Particularly, an input force profile with discrete spectrum is optimized to maximize the Fisher information matrix of the linear compliance model of the soft material.

Abstract: A method useful to change a system's output from one value to another within a prescribed time-interval in an optimal manner using optimization criteria such as minimal time (e.g., to increase throughput) or minimal energy (e.g., to reduce heat dissipation and reduce induced vibrations). Optimal design of maneuvers (such as fast seek and scanning) that rapidly change the output from one value to another, arise in flexible structure applications, including rapidly positioning the end-point of large-scale space manipulators, positioning of read/write heads of disk-drive servo systems, which are relatively medium-scale flexible structures, and nano-scale positioning and manipulation using relatively small-scale piezo actuators. Maintaining a position of an element constant outside of the transition time-interval is critical in many applications.

Abstract: A method useful to change a system's output from one value to another within a prescribed time-interval in an optimal manner using optimization criteria such as minimal time (e.g., to increase throughput) or minimal energy (e.g., to reduce heat dissipation and reduce induced vibrations). Optimal design of maneuvers (such as fast seek and scanning) that rapidly change the output from one value to another, arise in flexible structure applications, including rapidly positioning the end-point of large-scale space manipulators, positioning of read/write heads of disk-drive servo systems, which are relatively medium-scale flexible structures, and nano-scale positioning and manipulation using relatively small-scale piezo actuators. Maintaining a position of an element constant outside of the transition time-interval is critical in many applications.