Abstract: A dual-acting solenoid, consisting of one armature moving between two latching positions against two yokes with two drive windings, is interconnected to bring out three wire terminations: a center and two ends. The electronic drive circuitry is similarly configured for three terminals. Optionally, the drive circuitry includes sensing and computation sufficient to determine the two currents and the two inductive voltages associated with the two windings. A method is shown for using six measured or computed parameters, two inductive voltages, two currents, and two time derivatives of current, to determine the simultaneous position and velocity of the armature. The method involves simultaneous solution of the equations for current and voltage in two time-varying inductors where the two inductances are constrained to correspond to the position of a single armature moving between two fixed magnetic yokes.

Abstract: A system and method for state space control of solenoids, particularly engine valve solenoids with two latching positions. A collection of trajectories are computed or measured, having low-impact landings with latching from different initial energies. The trajectories define flux linkage and electric current functions of the two variables, position and velocity. These tracking functions define future projections based on present inputs. In operation, the controller monitors position, velocity, flux linkage, and current, uses the functions to compute future current and flux linkage, and adjusts the drive voltage to hit the future flux linkage target, causing the system to track a precomputed trajectory to successful landing. An array of tracking functions incorporates varying valve flow influences and corrective actuation. Drift from a precomputed trajectory indicates an unanticipated valve flow influence and a new tracking function selection, leading to course corrections anticipating flow influences.

Abstract: Servo controlled solenoids provide actuation of a pump piston and valves, and electronic LC resonance measurements to determine liquid volume and gas bubble volume. Third order nonlinear servo control is split into nested control loops: a fast nonlinear first-order inner loop causing flux to track a target by varying a voltage output, and a slower almost linear second-order outer loop causing magnetic gap to track a target by controlling the flux target or the inner loop. The inner loop uses efficient switching regulation, preferably based on controlled feedback instabilities, to control voltage output. The outer loop achieves damping and accurate convergence using proportional, time-integral, and time-derivative gain terms. The time-integral feedback may be based on measured and target solenoid drive currents, adjusting the magnetic gap for force balance at the target current.

Abstract: A solenoid with improved pull-in and landing characteristics. As a solenoid armature closes toward contact with the pole faces of a yoke, a geometric redistribution of a constant total flux causes the force to increase with decreasing gap. Latching force at saturation is maximized when the latching contact area matches the tightest bottleneck in the flux path. The addition of ferromagnetic area not making latching contact preserves the maximum latching force, increases power efficiency for pulling at a distance, and increases the flux redistribution effect of increasing force with decreasing gap at constant flux. The extra constant-flux force change at small gaps may be abrupt, for a high deceleration followed by a quick passive force increase to latch with low impact, or gradual, for tight servo control and very low impact. Conductive material can provide selective inductive damping near latching. Armature mass can be kept low despite the extra ferromagnetic area.

Abstract: A system and method for state space control of solenoids, particularly engine valve solenoids with two latching positions. A collection of trajectories are computed or measured, having low-impact landings with latching from different initial energies. The trajectories define flux linkage and electric current functions of the two variables, position and velocity. These tracking functions define future projections based on present inputs. In operation, the controller monitors position, velocity, flux linkage, and current, uses the functions to compute future current and flux linkage, and adjusts the drive voltage to hit the future flux linkage target, causing the system to track a precomputed trajectory to successful landing. An array of tracking functions incorporates varying valve flow influences and corrective actuation. Drift from a precomputed trajectory indicates an unanticipated valve flow influence and a new tracking function selection, leading to course corrections anticipating flow influences.

Abstract: A solenoid with two magnetically separate yoke regions, providing two distinct armature latching positions, is driven by a single effective winding. In one embodiment, the yoke regions consist of U-cores on either side of the armature and a single winding consisting of multiple turns, each turn looping through both U-cores and looping around the ends of the armature. In a second embodiment, distinct winding regions associated with the separate yoke regions are interconnected in series to make a single effective winding. Passage of the armature across a defined central position of minimum inductance is detected electrically, permitting a determination of absolute flux at a position of known inductance and thereby initializing a flux integration over time.

Abstract: A solenoid with two magnetically separate yoke regions, providing two distinct armature latching positions, is driven by a single effective winding. In one embodiment, the yoke regions consist of U-cores on either side of the armature and a single winding consisting of multiple turns, each turn looping through both U-cores and looping around the ends of the armature. In a second embodiment, distinct winding regions associated with the separate yoke regions are interconnected in series to make a single effective winding. Passage of the armature across a defined central position of minimum inductance is detected electrically, permitting a determination of absolute flux at a position of known inductance and thereby initializing a flux integration over time.

Abstract: A variable reluctance solenoid includes an armature and a yoke located axially beyond one end of the armature. Magnetic attraction across an axial gap between the armature and yoke causes the armature to move axially and close the gap. The armature includes ferromagnetic laminations lying in a plane perpendicular to the axial direction. These laminations may include slots, proportioned and directed to combat eddy currents and reduce moving mass while avoiding creation of flux bottlenecks. The solenoid may have two yokes on opposite sides of the armature, providing reciprocating armature motion.

Abstract: A spring system includes an axially moving center attachment located between two static attachments. Bi-directional axial center deflections cause push-pull restoration forces. There is little mechanical fixturing preload stress acting on material also subjected to high cyclic stresses. The spring material includes an unbroken path between the two static attachments, going through the center attachment. In one embodiment, the unbroken path is a length of wire bent into substantially parallel side-by-side helices clamped statically at the bottom of each helix. A moving attachment grips the center of the wire bridging diagonally between the tops of the helices. In a second embodiment, the unbroken path is a length of wire bent into end-to-end helices sharing a common axis and clamped statically at the axially opposite ends of the spring.

Abstract: A solenoid with improved pull-in and landing characteristics. As a solenoid armature closes toward contact with the pole faces of a yoke, a geometric redistribution of a constant total flux causes the force to increase with decreasing gap. Latching force at saturation is maximized when the latching contact area matches the tightest bottleneck in the flux path. The addition of ferromagnetic area not making latching contact preserves the maximum latching force, increases power efficiency for pulling at a distance, and increases the flux redistribution effect of increasing force with decreasing gap at constant flux. The extra constant-flux force change at small gaps may be abrupt, for a high deceleration followed by a quick passive force increase to latch with low impact, or gradual, for tight servo control and very low impact. Conductive material can provide selective inductive damping near latching. Armature mass can be kept low despite the extra ferromagnetic area.

Abstract: Servo control using ferromagnetic core material and electrical windings is based on monitoring of winding currents and voltages and inference of magnetic flux, a force indication; and magnetic gap, a position indication. Third order nonlinear servo control is split into nested control loops: a fast nonlinear first-order inner loop causing flux to track a target by varying a voltage output; and a slower almost linear second-order outer loop causing magnetic gap to track a target by controlling the flux target of the inner loop. The inner loop uses efficient switching regulation, preferably based on controlled feedback instabilities, to control voltage output. The outer loop achieves damping and accurate convergence using proportional, time-integral, and time-derivative gain terms. The time-integral feedback may be based on measured and target solenoid drive currents, adjusting the magnetic gap for force balance at the target current.

Abstract: A variable reluctance solenoid includes an armature and a yoke located axially beyond one end of the armature. Magnetic attraction across an axial gap between the armature and yoke causes the armature to move axially and close the gap. The armature includes ferromagnetic laminations lying in a plane perpendicular to the axial direction. These laminations may include slots, proportioned and directed to combat eddy currents and reduce moving mass while avoiding creation of flux bottlenecks. The solenoid may have two yokes on opposite sides of the armature, providing reciprocating armature motion.

Abstract: A system for measuring and controlling solenoid armature position. The system determines inductive voltage in the drive winding of the solenoid, integrates that voltage to obtain flux, and uses the current/flux ratio to measure armature position. To overcome integration drift, the current/flux position measure is compared to an independent position measure, this comparison leading to a drift correction. In an embodiment maintaining a servo-controlled position, flux drift causes position drift and current drift, the latter providing an independent measure of position drift and flux drift, permitting drift correction. In a second embodiment, a high frequency component of the drive voltage (possibly from pulse width modulation) and a high frequency current measurement provide the independent measure of position.

Abstract: Servo control using ferromagnetic core material and electrical windings is based on monitoring of winding currents and voltages and inference of: magnetic flux, a force indication; and magnetic gap, a position indication. Third order nonlinear servo control is split into nested control loops: a fast nonlinear first-order inner loop causing flux to track a target by varying a voltage output; and a slower almost linear second-order outer loop causing magnetic gap to track a target by controlling the flux target of the inner loop. The inner loop uses efficient switching regulation, preferably based on controlled feedback instabilities, to control voltage output. The outer loop achieves damping and accurate convergence using proportional, time-integral, and time-derivative gain terms. The time-integral feedback may be based on measured and target solenoid drive currents, adjusting the magnetic gap for force balance at the target current.

Abstract: A levitated rotor, neutrally buoyed in ultrasound transmission fluid, moves to position and aim an ultrasound transducer in up to five servo-controlled coordinates of position and tilt rotation. Stator drive/sense windings drive the rotor via a rotor magnet and sense coordinates via inductive interactions with a rotor coil. For five-axis control, one set of stator windings controls two-axis lateral translation while a second set controls axial translation plus two-axis tilt rotation. The windings produce a comparatively linear relationship between the five rotor geometric coordinates and the electromagnetic couplings that drive and sense these coordinates. To produce this linearity seamlessly over a wide coordinate range coming close to the windings, each set of windings is divided into overlapping subsets. A two-way drive/sense matrix mapping translates between up to five control coordinates and more than five winding circuits.

Abstract: A method of determining electrochemical charge acceptance limits by measuring and determining the peak of the curve of Differential Equivalent Series Resistance (DESR) of a cell or system for the purpose of monitoring or controlling processes internal to the cell/system (i.e.; state-of-charge or state-of-formation) or for monitoring or controlling processes external to the cell/system (i.e.; battery chargers or battery formers). The method is suitably embodied in software, firmware, hardware, or apparatus.

Abstract: The invention is a device for controlling a sound reproduction transcriber which provides alternate playback intervals and stopped intervals. The playback interval length in words and the average word reproduction rate are manually selectable by a secretary or instructor. The device meters the reproduced words during the playback interval and initiates the stopped interval at the first audio pause after the selected number of words have been played back. The required total cycle time is computed by effectively dividing the number of words played back during the playback interval by the selected average word reproduction rate. A timer, which counts the time elapsed since the playback interval was initiated, has its counted time compared to the computed total cycle time so that the stopped interval is terminated, the circuit is reset and the playback interval is again initiated upon coincidence of the computed time and the elapsed time.