Abstract: Systems and methods are provided for use in assessing the stability of simultaneous machining (SM) dynamics (which is also known as parallel machining). In SM, multiple cutters, which are generally driven by multiple spindles at different speeds, operate on the same work-piece. In an alternative implementation of SM, single milling cutters with non-uniformly distributed cutter flutes operate on a work-piece. When SM is optimized in the sense of maximizing the rate of metal removal constrained with or by the machined surface quality, “chatter instability” phenomenon appears. The present disclosure declares the complete stability picture of SM chatter within a mathematical framework of multiple time-delay systems (MTDS). A cluster treatment of characteristic roots (CTCR) procedure determines the regions of stability completely in the domain of the spindle speeds for varying chip thickness, thereby replicating the well-known “stability lobes” concept of STM for simultaneous machining.

Abstract: A microinjection device is provided that includes an injection element defining a longitudinal axis, and that further includes a motor. The injection element is rotatable about the longitudinal axis by the rotational motor. The injection element is for penetrating a target, such as a cell. A microinjection system is provided that includes the microinjection device and a control unit. The control unit is for controlling a rotational amplitude and a frequency of oscillation of the injection element. A method for penetrating a target to facilitate injecting material therein is provided that includes providing the material to an injection element, contacting the target with a distal end of the injection element, rotating the injection element about a longitudinal axis to form a hole in the target, and penetrating the target with the injection element via the hole formed in the target.

Abstract: Systems and methods are provided for use in assessing the stability of simultaneous machining (SM) dynamics (which is also known as parallel machining). In SM, multiple cutters, which are generally driven by multiple spindles at different speeds, operate on the same work-piece. In an alternative implementation of SM, single milling cutters with non-uniformly distributed cutter flutes operate on a work-piece. When SM is optimized in the sense of maximizing the rate of metal removal constrained with or by the machined surface quality, “chatter instability” phenomenon appears. The present disclosure declares the complete stability picture of SM chatter within a mathematical framework of multiple time-delay systems (MTDS). A cluster treatment of characteristic roots (CTCR) procedure determines the regions of stability completely in the domain of the spindle speeds for varying chip thickness, thereby replicating the well-known “stability lobes” concept of STM for simultaneous machining.

Abstract: A “harmonic force generator” (HFG) is provided which creates counter-acting forces to a harmonic excitation. The advantageous HFG devices of the present disclosure may be used in canceling the undesired vibrations on a structure under the influence of a harmonic excitation. There are critical aspects to be controlled in the output force: the amplitude, the frequency and the relative phase with respect to given harmonic signal. All three of these components are adjusted by a closed loop control structure according to the present disclosure. The controller determines the transition time of all three features. The disclosed HFG advantageously produces this harmonically varying force only along a determined axis, with no force component in transverse direction.

Abstract: Torsional vibrations in a rotating structure having a relatively large mass and subject to varying frequencies of torsional excitation are damped by determining the frequency of torsional excitation of the rotating structure and coupling to the rotating structure a damping pendulum of smaller mass to provide an absorber unit rotating therewith. The angular displacement of the damping pendulum relative to the rotating structure is continuously monitored, and the frequency of excitation is determined. The monitored displacement of the damping pendulum together with the mass damper characteristics of the absorber unit are processed to output a signal which produces a control torque on the damping pendulum proportional to the monitored displacement of the damping pendulum with a controlled time delay to produce control torque on the damping pendulum substantially equal to the torsional excitation of the rotating structure.

Abstract: Vibrations in a structure having a large mass and a multiplicity of frequencies of excitation are damped by determining two principal frequencies of excitation for the structure and coupling thereto a damping member of smaller mass to produce an absorber. The spring damper characteristics of the absorber are determined at these frequencies and the displacement of the damping member is monitored. The monitored displacement of the damping member is processed together with the spring damper characteristics of the absorber to output a signal which produces a force acting on the damping member proportional to the displacement of the damping member with a controlled time delay. This produces two frequencies of vibration in the damping member substantially equal to the determined frequencies of excitation of the large structure and thereby produces resonance of the damping member substantially at the determined frequencies of excitation.

Abstract: Vibrations in a structure having a large mass are damped by coupling thereto a damping member of smaller mass and continuously monitoring the frequency of excitation of the structure produced by applied load(s) and the displacement of the damping member. The monitored frequency of excitation and displacement of the damping member are processed together with data relative to the mass, stiffness and damping characteristic of the damping member. A signal is outputted to produce a force acting on the damping member proportional to the displacement of the damping member with a controlled time delay to produce a frequency of vibration in the damping member substantially equal to the monitored frequency of excitation of the structure, this produces resonance of the damping member substantially at the monitored frequency of excitation and is effective to damp substantially the vibrations of the structure at the monitored frequency of excitation.