Data processing: measuring – calibrating – or testing – Calibration or correction system – Speed
Reexamination Certificate
2001-02-26
2003-01-14
Hilten, John S. (Department: 2863)
Data processing: measuring, calibrating, or testing
Calibration or correction system
Speed
C068S023200, C073S490000, C327S311000, C377S023000, C340S988000
Reexamination Certificate
active
06507799
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to the filtering and sampling of data to improve microprocessor data acquisition. More particularly, this invention relates to reducing the speed requirements for microprocessors that acquire data for realtime processing of force and acceleration measurements from rotating structures such as a washing machine tub or drum.
In the appliance market, market research shows the need for bigger capacity washing machines. To fill this need, the tub has to be larger to accommodate larger washing loads. The tub is also known as the spinner. Under certain conditions, the clothing load in the tub will become unbalanced. This causes the spinning tub to vibrate and move out of its normal position. In the United States, when the size of the tub is increased, the size of the cabinet which houses the tub and other washing machine components is also increased. The cabinet size is increased with the tub size to maintain spatial clearances between the tub and the cabinet. These clearances are required so that an unbalanced load in the tub will not cause the tub to slam into the cabinet as the tub rotates, for example, during the spin cycle or tumbling cycles. However, in the European market, a fixed washing machine cabinet size is required. Increasing the tub size while maintaining a fixed cabinet size leaves little room for movement of the tub during a spin cycle with an unbalanced load.
To keep the tub from contacting the sides of the cabinet while it is rotating, a system for dynamically “balancing the tub” during the spin cycle has been developed. Balancing the tub involves adding weight to certain areas of the tub to counter balance an unevenly distributed load of clothes or other material being washed. This is done by using a tub with a series of “fluid pockets” in the front and back of the tub. These pockets are strategically filled with fluid during the spin cycle to counterbalance the wash load and keep the tub from shaking and contacting the sides of the cabinet. This technology is more fully described in U.S. Pat. No. 5,561,993, entitled “Self Balancing Rotatable Apparatus,” assigned to Honeywell Inc. The fluid could comprise one of many types of fluid or combinations thereof but preferably is a 70% by weight water and 30% by weight calcium chloride mixture.
Those skilled in the art of balancing rotating structures, such as tires on automobiles, are well aware of the use of computers in balancing. Typically, sensors near the rotating structure send data to a computer which calculates an appropriate correction to balance the structure. In the case of tires, the computer instructs the technician to attach an amount of weight at a certain location on the tire rim.
Balancing a washing machine tub as it is rotating is much more complicated than balancing a tire as it must be performed without the luxury of stopping the rotating structure to mount weight in the appropriate position. Dynamic balancing must occur in realtime; therefore, timely data acquisition and the ability to process that information quickly are of utmost importance. Force and acceleration sensors near the tub convey data to a microprocessor which determines the extent of the unbalance, computes the corrective remedy, and controls the implementation of that remedy.
Present methods of collecting and converting data to a digital form require that large amounts of data be processed in a short period of time to balance the tub. The quantity of data is large because massive oversampling is required to provide the measurement accuracy necessary to balance the tub. Oversampling in this context means that many more data points are sampled within a period of time, thus sending a stream of data to a computer or microprocessor at a very high rate. The computer, in turn, must process this data in realtime as it cannot store the data for later processing. The computer must take each piece of data and process it before proceeding to the next piece of data. Each processing step may require several processing BUS cycles during which computer commands are executed. Therefore, the faster the data comes into the computer, the faster the computer must be to keep up with the flow of information to generate an appropriate corrective remedy. To make matters more difficult, the faster the washing machine tub spins, the faster data must be collected to provide an accurate representation of the unbalanced condition of the tub. Sampling frequencies are directly correlated with the rate of rotation of the washing machine tub. A washing machine tub may spin at 1,100 revolutions per minute (RPM). At these high rotation speeds, data from the rotating tub must be sampled at a very high rate or frequency in order to construct an accurate picture of the actual forces and accelerations being exerted by the tub. The oversampling required by prior technology is in the range of 1 to 5 kHz, which can only be accomplished with higher-priced microprocessors. Therefore, oversampling requires the use of microprocessors with processing speeds as high as 100 to 200 MHz, causing the cost of the entire washing machine to become prohibitively high.
U.S. Pat. No. 5,561,993 (the “'993 patent”) illustrates the data acquisition difficulties found in the prior art. In the '993 patent, a fixed-frequency low-pass filter is used before the data is sampled and a narrow tunable band pass filter is employed to further try to eliminate noise in the signal. This band pass filter is implemented through software in the microprocessor. Therefore, the microprocessor must process a large quantity of digital data to remove the noise before it can begin to analyze the data for its intended purpose. As such, the prior art methods require prohibitively fast and needlessly complex microprocessors to perform tasks such as described herein.
Moreover, sampling at a fixed frequency has significant disadvantages. For example, in the prior art, data is sampled at a fixed frequency for all rates of rotation of the washing machine tub. In this example, as the rotating tub slows down, the number of data points per revolution of the tub increases. This in turn increases the number of BUS cycles per revolution required by the microprocessor to calculate a correction to an unbalanced condition. In practice, unbalance conditions often manifest themselves at these intermediate speeds. Therefore, the microprocessor may actually work harder at the lower rates of rotation of the structure, and a faster microprocessor may be required to balance rotating tubs even at lower and intermediate speeds.
A need exists for a device which reduces the microprocessor speed requirements for data acquisition while maintaining the integrity of the data. This will allow slower microprocessors to be used in applications that otherwise would require fast microprocessors, improving the realtime analysis of data intensive washing machine balancing. Furthermore, a need exists to have the ratio of BUS cycles per revolution be a constant at any rate of revolution of the tub.
REFERENCES:
patent: 3799348 (1974-03-01), Mazza
patent: 3983035 (1976-09-01), Arkeveld et al.
patent: 4000658 (1977-01-01), Schmidt
patent: 4157781 (1979-06-01), Maruyama
patent: 4322641 (1982-03-01), Packard
patent: 4694156 (1987-09-01), Swanberg
patent: 4991247 (1991-02-01), Castwall et al.
patent: 5150314 (1992-09-01), Garratt et al.
patent: 5280660 (1994-01-01), Pellerin et al.
patent: 5325677 (1994-07-01), Payne et al.
patent: 5376063 (1994-12-01), Greenstein
patent: 5490436 (1996-02-01), Coyne et al.
patent: 5561993 (1996-10-01), Elgersma et al.
patent: 5582040 (1996-12-01), Khan
patent: 5692313 (1997-12-01), Ikeda et al.
patent: 5715731 (1998-02-01), Koch
patent: 5761932 (1998-06-01), Kim
patent: 5761933 (1998-06-01), Kim et al.
patent: 5765402 (1998-06-01), Ikeda et al.
patent: 5850748 (1998-12-01), Kim et al.
patent: 5862553 (1999-01-01), Harberl et al.
patent: 5870907 (1999-02-01), Cho
patent: 5893280 (1999-04-01), Honda et al.
patent: 5913951 (1999-06-01), Herr et al.
patent: 592
Fredrick Kris T.
Hilten John S.
Honeywell International , Inc.
Le John
LandOfFree
Method and apparatus for reducing microprocessor speed... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for reducing microprocessor speed..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for reducing microprocessor speed... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3056259