General Electric Company

General Elec. Co.

James F Bedard

Charles W Eichelberger

Steven Robert Hayashi

Charles E Thomas

Salvatore F Nati, Jr

Minyoung Lee

Walter Whipple

Lawson P Harris

Scott E Cutler

Vivek Venugopal Badami

Douglas Glenn Wildes

William C Hughes

Edward B Miller

George Charles Goodman

Vijay C Jaswa

William S Yerazunis

Salvator F Nati, Jr

Theodore Henry Klotz, Jr

Vilay C Jaswa

De-Yu Chen

A capacitive proximity detection system for positioning a movable radiation imaging element support structure with respect to a subject includes a plurality of sensor plates disposed in a collar assembly around a portion of an imaging component disposed towards a subject; a multiplexer coupled to the plurality of capacitive plate elements and adapted to selectively electrically couple the sensor plate elements in one of a plurality of sensing range modalities; and a capacitive sensing processor coupled to the sensor plate elements via the multiplexer so as to detect proximity of object to the sensor plate as a function of the capacitance between the sensor plates and the subject. The imaging system typically further includes a shield system coupled to the multiplexer and disposed so as to focus the capacitive sensing of the sensor plate elements towards the subject. The shield system includes a plurality of shielding plate elements disposed in a shielding pattern that corresponds with the pattern of sensor plate elements in the collar assembly. The shield plate elements are coupled to the capacitive sensing processor to receive a shield plate feedback signal therefrom.

Capacitive proximity detector for radiation imager position control

A tool break detection system has an automatic gain control to adjust the analog signal channel gain and hold the cutting vibration signal at a desired average level. The AGC time constant is long enough that the detection of abrupt tool breaks and sudden large signal level transistions by the digital signature recognition logic is unaffected. However, the gradual decrease in signal level produced by a crumbly-type break would be removed by AGC action. In a system with a hardware AGC, crossing a high gain threshold resets gain to a low value and the resulting abrupt and persisting change in signal level is detected by the abrupt tool break logic. Another embodiment uses the gain command output by a software AGC and generates a break detected signal directly, without resetting the gain command, as gain rises above a high gain alarm level which is recalculated at the start of each cut.

Detection by automatic gain control features of gradual cutting tool

An acoustic tool break detector monitors vibration caused by a cutting process and has an analog amplifier to condition the signal, then searches for a rapid sustained change in signal level indicative of a cutting tool break. An automatic gain control circuit dynamically controls the gain of the analog amplifier and adjusts the output cutting noise signal to a desired average level during an active cut while allowing use of such a break algorithm. The time rate at which the AGC changes gain is constant and independent of gain; it is set such that a gain change of 2:1, for instance, takes longer than the confirmation period for a tool break. The analog amplifier has a variable attenuator whose gain is set by the outputs of an up/down counter; these outputs are fed back to a variable clock whose rate is dependent on gain at any instant. The clock outputs drive the counter until the analog cutting noise signal is within a preselected window.

Automatic gain control for machine tool monitor

A Machine Tool Monitor detects significant cutting tool breakage and the first contact of an advancing tool to a workpiece, and does this by monitoring vibration signals produced by the machining of parts and interpreting patterns in these signals. Information from the part program improves the performance of the detector and optimizes it for the cutting conditions called for by the machine tool control. The analog channel gain of the monitor is adjusted and parameters controlling the digital pattern recognition logic are selected using part program information on machining parameters. The tool touch or tool break detection mode is selected by the part program.

Vibration-sensing tool break and touch detector optimized for machining

A self-checking detector for detecting faults in a multiple redundant clock system includes a majority voter circuit for receiving the clock signals from the redundant clock circuits and for providing a voted output, a comparison circuit for comparing each of the clock signals with the voted output, and failure signal producing circuits responsive to the outputs from the comparison circuit for producing a first failure signal upon a clock failure being detected and for producing a second failure signal upon a failure of the majority voter being detected. The detector further includes power-up reset circuitry for inhibiting its operation during a power-up interval, and a reset circuit enabling either automatic or manual reset of the detector for verification of the detected fault.

Self-checking digital fault detector for modular redundant real time

Three hardware real time clock subcircuits are connected in a triple modular redundancy configuration to assure continued operation if one subcircuit fails. A power supply or processor failure will not cause a clock supplying other processors to fail. Output of voted master clock pulses to the counter in every subcircuit is inhibited until all power supplies are turned on and stabilized, and the time base of the real time clock pulses is variable. The output pulses of all subcircuits are voted on and the voter output is the real time clock. The master clock can be the processor clock.

Fault-tolerant real time clock

Substantial cutting condition changes that occur gradually, as opposed to the more usual sudden large change, are detected by setting upper and lower cutting noise mean level thresholds. When the mean cutting noise exceeds the upper threshold or stays below the lower threshold for a preset number of signal samples, a tool break alarm is generated. Techniques are given to reduce false alarms at the start and end of the cut and on runout on initial rough surface cuts. The system comprises an accelerometer or other sensor whose signal is preprocessed to attenuate lower frequency machinery noise and detect the signal energy in a band below 100 KHz, then sampled, and the digitized signal samples analyzed by pattern recognition logic.

Acoustic tool break detection system and method

This tool break detection system relies on monitoring changes in the cutting noise itself, rather than detecting the tool fracture acoustic signal. A broken tool capable of damaging the workpiece is detected, and tool break events that do not affect cutting conditions are ignored. The signal from a sensor such as an accelerometer is preprocessed to attenuate low frequency machinery noise and detect the signal energy in a band below 100 KHz, then sampled, and the digitized signal samples analyzed by pattern recognition logic. Runout false alarms during rough surface cutting are prevented; after detection of an abrupt increase or decrease in signal level, the confirmation period to test for a persistent shift in mean level is set longer than the workpiece revolution period.

Acoustic monitoring of cutting conditions to detect tool break events

A system and method for monitoring vibrations of a machine tool metal-cutting tool insert and interpreting them to promptly detect the initial touch to the workpiece and signal the tool to stop advancing before marring the surface. The signal generated by a sensor such as an accelerometer is preprocessed to eliminate lower frequency machine noise and detect the energy in a higher frequency band, then sampled and analyzed by digital circuitry. In order to avoid false alarms on high amplitude spiky noise pulses generated by traverse operation of the machine tool, the tool touch alarm is delayed longer than the maximum duration of the noise pulses. Two techniques are given to ignore the noise spikes while still detecting the tool touch signal.

Acoustic detection of contact between cutting tool and workpiece

Methods for operating a control circuit, having a programmable signal characteristic, in a manner so as to gradually vary a D.C. analog output level from an initial value to a final value, as well as for abrupt changes therein, when an isolation-and-rectification network is used to recover a D.C. voltage of programmably controlled amplitude. The methods also provide for a pulsed output condition in a circuit for providing a periodic signal of programmably controlled amplitude. In such a circuit, the output signal amplitude may be controlled by external data signals to values less than, equal to and greater than, the substantially constant amplitude of an oscillator waveform. Both programmable (computer-controlled) and hard-wired circuitry are disclosed for controlling the output signal by the methods of this invention.

Control circuit and method for varying the output of a waveform

A system for programmable controlling the output level of at least one load, utilizes an isolated receiver-controller located adjacent to the load and receiving control data from at least one transmitter, which may be at a location remote from the load location. The transmitted data includes an address portion, identifying that particular one of a plurality of loads having the corresponding local address, and a command data portion, establishing both the on/off condition and the output level of the addressed load. Local control may be temporarily substituted for remote control. The output level is controlled by programmably varying the magnitude of an impedance coupled to a pair of load input terminals.

System for load output level control

A circuit, for providing a periodic signal of programmably controllable amplitude, includes an oscillator having a substantially constant amplitude signal of desired frequency and waveform at an output thereof connected to the input of a first programmable voltage divider having its output connected to one input of an operational amplifier. The remaining operational amplifier input is connected to the output thereof via a second programmable voltage divider used as a programmably controllable feedback network. The operational amplifier output signal amplitude may be controlled by external data signals to values less than, equal to, and greater than, the substantially constant oscillator waveform amplitude. Both computer and hard-wired circuitry for controlling the output signal are disclosed. An isolation-and-rectification network may be used to recover a D.C. voltage of programmably controlled amplitude.

Programmable signal amplitude control circuits

A control module for controlling at least one variable-power-consuming load responsive to data input from local and/or remote locations, utilizes a controller microcomputer having an output setting the gain of a variable gain amplifier. The variable gain amplifier operates on a substantially-constant output of an oscillator to provide, on a cycle-by-cycle or long-term basis, a periodic waveform of controlled amplitude to the at least one load. The amplitude of the waveform sets the energy consumption/output of the load. Another data bus facilitates connection of local control means to a control module interface providing local control information to the controller microcomputer, while a third data bus is dedicated to communication with a remote central controller, if used. The control module includes circuitry for allowing a unique local address to be set for a particular control module, to which unique address the control module responds when a plurality of such control modules are connected in parallel to a central controller. A fourth data bus connects local sensors, such a photocells, thermistors and the like, through analog-to-digital conversion circuitry to the controller microcomputer, to facilitate control of the local loads responsive to local ambient conditions. The maximum level of the load(s) connected to a control module may be programmably established such that this maximum level can not be exceeded by local and/or remote commands, until the maximum level is altered.

Control module for engergy management system

A passive control network for connection between a pair of load output level setting terminals, as on a ballast for a dimmable fluorescent lamp in a lighting system, to provide a required variable impedance, where the magnitude of the impedance establishes the load output level. The passive control network includes an isolation transformer for coupling a periodic waveform at the load input terminals to the variable impedance component, the magnitude of which impedance is reflected through the transformer to provide the load level-setting impedance.

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Schenectady, NY, United States of America

James F Bedard