Method for controlling a spin cycle of a washing machine and washing machine

Abstract

Method for controlling a spin cycle of a washing machine and washing machine comprising a suspended group (10) including a rotative drum (11) contained in a dampened enclosure (12) supported on a suspension mechanism (20), a two axes accelerometer (30) supported on the suspended group (10), the method comprises the steps of capturing and analyzing vibration data (40) relative to the vibration of the suspended group (10) detecting a vibration data variation (43) over time indicative of a weight variation of the clothes due to the loss of water and determining a stabilization of the vibration data variation (43) over time indicative of the steadiness of the weight variation of the clothes due to end of the loss of water.

Claims

1. Method for controlling a spin cycle of a washing machine, the washing machine comprising: a suspended group including a rotative drum contained in a dampened enclosure supported on a suspension mechanism, the rotative drum being connected to the dampened enclosure through a driving shaft actuated through a variable-speed motor to produce a rotation of the rotative drum around a rotation axis; a two axes accelerometer connected to an electronic control and supported on the suspended group to determine an acceleration of the rotative drum in two orthogonal axes perpendicular to the rotation axis; wherein the method comprises: performing a centrifugal cycle by accelerating the rotative drum to a centrifugal speed adjusted to retain clothes contained in the rotative drum against an inner perimeter of the rotative drum by a centrifugal force and by draining water from the dampened enclosure; capturing, during the centrifugal cycle by said two-axis accelerometer, vibration data relative to the vibration of the suspended group, produced by weight offset of the clothes; analyzing, during the centrifugal cycle and by the electronic control unit, the vibration data, provided by the two axes accelerometer, detecting a vibration data variation over time, indicative of a weight reduction of the clothes due to the loss of water; analyzing, during the centrifugal cycle and by the electronic control unit, the vibration data variation to determine a stabilization of the vibration data variation over time when the vibration data decreases at a pace below a predefined stabilization threshold, indicative of the steadiness of the weight reduction of the clothes due to end of the loss of water; and triggering an end of the centrifugal cycle in response to the stabilization of the vibration data variation.

2. The method according to claim 1 wherein the analysis of the vibration data includes a filtration of the vibration data to isolate the maximal amplitude of each vibration, measured by the two axes accelerometer, disregarding the direction of said vibration in a plane perpendicular to the rotation axis of the rotative drum, obtaining maximal amplitude vibration parameters from which a vibration reduction profile is calculated, using said vibration reduction profile to determine the stabilization of the vibration data variation over time.

3. The method according to claim 2 wherein the filtration process further includes disregarding vibration data having a statistically deviation from the surrounding vibration data above a predefined deviation threshold.

4. The method according to claim 2 wherein the maximal value of the vibration reduction profile, at the beginning of the centrifugal cycle once the centrifugal speed has been achieved, is set to be a reference value 100%, defining the rest of the vibration reduction profile as a % in regard to said reference value 100%, the stabilization threshold also being determined as a % in regard to said reference value 100%.

5. The method according to claim 2 wherein, during the centrifugal cycle, the vibration data variation, used to detect the stabilization of the vibration data variation, is calculated between several successive pairs of predefined time points, or between several successive pairs of equidistant predefined time points, determining the stabilization of the vibration data variation when one or several successive calculated vibration data variations are below the predefined stabilization threshold.

6. The method according to claim 1 wherein if, at the beginning of the centrifugal cycle, the analysis of the vibration data determines that the maximal amplitude of the vibrations is equal or above a predefined first vibration threshold the centrifugal cycle is aborted, stopping the rotative drum or reducing the rotation speed of the rotative drum to a tumbling speed, to change the clothes distribution within the rotative drum and a new centrifugal cycle is later restarted.

7. The method according to claim 6 wherein if, at the beginning of the centrifugal cycle, the analysis of the vibration data determines that the maximal amplitude of the vibrations is comprised between the predefined first vibration threshold and a predefined second vibration threshold lower than the predefined first vibration threshold, the rotation speed of the rotative drum is maintained during a predefined period of time and, if after said predefined period of time the maximal amplitude of the vibrations remains above the second vibration threshold, then the centrifugal cycle is aborted, stopping the rotative drum or reducing the rotation speed of the rotative drum to the tumbling speed, to change the clothes distribution within the rotative drum and a new centrifugal cycle is later restarted.

8. The method according to claim 7 wherein in successive centrifugal cycles attempts the first and second vibration thresholds are increased, maintaining the first vibration threshold below a maximal vibration threshold.

9. The method according to claim 7 wherein the centrifugal speed is automatically set to be a speed at which maximal amplitude of the vibrations reach the predefined second vibration threshold.

10. The method according to claim 9 wherein during the centrifugal cycle the centrifugal speed is increased maintaining the maximal amplitude of the vibrations equal or below said predefined second vibration threshold.

11. The method according to claim 1 wherein, before starting the centrifugal cycle, the rotative drum is accelerated to a test speed defined to produce a centrifugal force in the perimeter of the rotative drum comprised between 5 G and 12 G or preferably between 8 G and 11 G.

12. The method according to claim 1, wherein the method further comprises predicting by the electronic control unit, from initial vibration data 40 collected during the beginning of the centrifugal cycle analyzed by the control unit, an expected evolution of the vibration data variation during the rest of the centrifugal cycle and a time forecast until the stabilization of the vibration data variation, the time forecast being obtained from the analysis of the expected evolution of the vibration data variation.

13. A washing machine comprising: a suspended group including a rotative drum contained in a dampened enclosure supported on a suspension mechanism, the rotative drum being connected to the dampened enclosure through a driving shaft actuated through a variable-speed motor to produce a rotation of the rotative drum around a rotation axis; a two axes accelerometer supported on the suspended group to determine an acceleration thereof in two orthogonal axes perpendicular to the rotation axis of the rotative drum and connected to an electronic control to communicate vibration data relative to the vibration of the suspended group, produced by weight offset of the clothes; the electronic control is further configured to implement the method according to any of the preceding claims, and the two axes accelerometer is a single accelerometer.

14. The washing machine according to claim 13 wherein the suspension mechanism has been configured to avoid resonance with vibration parameters produced by the rotative drum rotating at a speed lower to those required to produce a centrifugal force in its perimeter of 12 G.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The foregoing and other advantages and features will be more fully understood from the following detailed description of an embodiment with reference to the accompanying drawings, to be taken in an illustrative and non-limitative manner, in which:

(2) FIG. 1 is a schematic view of the washing machine, wherein the front side of the dampened enclosure has been removed in seek of clarity;

(3) FIG. 2 is a schematic view of the vibration data obtained from the two axes accelerometer during a typical centrifugal cycle, and wherein the maximal amplitude of one single vibration has been drawn as a straight diagonal line;

(4) FIG. 3 is a schematic view of the filtered vibration data, showing only the evolution of the maximal amplitude of the vibrations during the centrifugal cycle, the maximal amplitude of the vibrations determining a line correspondent to the vibration data variation, which typically corresponds to a logarithmic-like decreasing line;

(5) FIG. 4 is a schematic view of the line defining the vibration data variation, wherein the several time periods have been indicated and the vibration data variation has been measured within each of said time periods;

(6) FIG. 5 is a flowchart showing one proposed embodiment of the proposed method.

DETAILED DESCRIPTION OF AN EMBODIMENT

(7) The foregoing and other advantages and features will be more fully understood from the following detailed description of an embodiment with reference to the accompanying drawings, to be taken in an illustrative and not limitative.

(8) FIG. 1 shows the proposed washing machine, which includes an external chassis, containing a suspended group 10 formed by a dampened enclosure 12 containing a rotative drum 11.

(9) The dampened enclosure 12 is connected to the external chassis through a suspension mechanism 20, for example formed by springs, elastic blocks, pistons, or a combination thereof, isolating the external chassis from the vibrations of the dampened enclosure 12.

(10) The rotative drum 11 is connected to the dampened enclosure 12 through a driving shaft actuated through a variable-speed motor to produce its rotation around a rotation axis E.

(11) The hollow interior of the rotative drum 11 is accessible through an opening of the dampened enclosure which can be hermetically sealed by a door, allowing for the introduction of extraction of clothes to be cleaned or dried.

(12) The rotative drum is typically a cylindrical drum with two circular side walls and a cylindrical perimetral wall. The rotative drum is perforated allowing the entry and exit of water but retaining inside the clothes to be washed.

(13) The dampened enclosure includes at least one water inlet and/or one soapy water inlet and one drainage outlet.

(14) The variable-speed motor is typically attached outside the dampened enclosure.

(15) The dampened enclosure 12 is connected to a drainpipe to evacuate the water contained therein.

(16) According to this embodiment, a two axes accelerometer 30 is attached to the dampened enclosure 12 to measure vibrations of the suspended group 10 in two orthogonal axis X and Y, defining a plane perpendicular to the rotation axis E, said vibrations being produced by the rotation of an eccentric weight distribution of the wet cloths within the rotative drum 11.

(17) FIG. 2 shows a graph of the vibration data 40 obtained by the two axes accelerometer 30. Each rotation of the rotative drum 11 produces one elliptic-like vibrational movement of the suspended group 10. Each elliptic-like vibration defines one maximal amplitude 41 of the vibration coincident with the longest diagonal of said elliptic-like vibrational movement.

(18) FIG. 3 shows the result of filtration of the vibrational data 40 to isolate the maximal amplitude 41 of each vibration during the centrifugal cycle.

(19) During the centrifugal cycle, the maximal amplitude 41 of the vibrations is reduced over time due to the loss of weight of the clothes contained in the rotative drum 11. Typically, the reduction of the maximal amplitudes 41 of the vibrations during the centrifugal cycle produces a logarithmic-like graph, corresponding to the vibration data variation 42, which tends to a horizontal asymptote. When the vibration data variation 42 approaches to the asymptote, it is indicative of the end of the loss of water of the clothes and the centrifugal cycle can be finished.

(20) FIG. 4 shows how, if the centrifugal cycle is divided in several time periods P1, P2, P3, . . . PN of the same extension, for example periods of between 10 seconds and 100 seconds, the reduction of the maximal vibration on each period is smaller than the reduction on the preceding periods. Once the reduction within one period is below a stabilization threshold, the stabilization of the loss of water is determined and the centrifugal cycle is ended.

(21) Preferably, after the determination of the stabilization of the vibration data variation 43, it is also verified if the centrifugal cycle has last for at least a minimal centrifugal period T2 before ending the centrifugal cycle, extending the centrifugal cycle until said minimal centrifugal period T2 has expired before finishing the centrifugal cycle.

(22) FIG. 5 shows a flowchart showing how the centrifugal cycle is controlled.

(23) At the beginning of the centrifugal cycle, once the centrifugal speed has been reached, if the vibration of the suspended group 10, preferably the maximal amplitude 41 of said vibrations, is above a first vibration threshold 1VT, the centrifugal cycle is aborted and restarted, producing a redistribution of the weight within the rotative drum 11.

(24) If the vibration is below said first vibration threshold 1VT, then it is verified if the vibration of the suspended group 10 is above a second vibration threshold 2VT lower than the first vibration threshold 1VT.

(25) When the vibration is below the second vibration threshold 2VT, the centrifugal cycle proceeds. When the vibration is above the second vibration threshold 2VT, then the centrifugal cycle is maintained for a period of time T1, for example a period comprised between 10 and 100 seconds, allowing for a certain loss of weight and vibration reduction. If after said period of time T1 the vibration is below the second vibration threshold 2VT, the centrifugal cycle proceeds. If after said period of time T1 the vibration is still above the second vibration threshold 2VT, then the centrifugal cycle is aborted and restarted, producing a redistribution of the weight within the rotative drum 11.

(26) Once these initial checks have been done successfully, the velocity of the reduction of the vibration is analyzed, for example verifying the vibration data variation 43 on said successive periods of time P1, P2, P3, . . . PN shown on FIG. 4.

(27) Once the vibration reduction is below a certain stabilization threshold, being then the loss of water irrelevant or almost irrelevant, the centrifugal cycle can be finished.

(28) If after a certain time, for example once the period PN is reached, the stabilization threshold has not yet been reached, the centrifugal cycle can be finished automatically to avoid an excessive duration thereof.