MEMSIC Out-of-Balance Application

Transcription

1 N MEMSI Inc. pplication Engineering epartment

2 Revision History URevision Uate Uuthor Uomments Rong Yi Initial Release Robbie ao dd more data plotting Rong Yi onvert into O format and translate into English MEMSI Property & onfidential Page 1 of 8 Tel: , Fax:

3 Table of ontents REVISION HISTORY... 1 TLE OF ONTENTS INTROUTION SYSTEM SETUP LOK IGRM SYSTEM SETUP ESRIPTION EXPERIMENT T PLOT T PLOT SUMMRY OF EXPERIMENT MEMSI Property & onfidential Page 2 of 8 Tel: , Fax:

4 1 Introduction When washing machine dryer drum is in the speed ramping up stage, the drum will usually lost its balance due to the clothing inside the drum is not balanced distributed. This phenomenon is called Out-Of-alance (OO) of dryer drum. The OO will generate abnormal vibration to the washing machine, which will generate noise, even lead to damage to the mechanical structure of the washing machine, or damage the electrical motor and related circuit. The traditional OO detection solution on the washing machine is an indirect detection method, which cannot precisely reflect the actual vibration motion model on the dryer drum. MEMSI OO etection Module (with MEMSI ccelerometer inside) is an innovational product, it can directly reflect the actual vibration model on the washing dryer drum by detecting the vibration acceleration in both X/Y plain axes. The unique thermal based technology of MEMSI accelerometer can provide a higher resolution, stable output, lower noise and higher reliability, which can work better and reliably in the extremely tough environment in a washing machine. MEMSI worked with the world-class appliance companies to make the MEMSI OO solution productized and demonstrated its worthy on the washing machine to improve the overall performance, especially reach a quiet & stable operating result. Following is some experiment that MEMSI worked with the appliance companies to field measure the acceleration with MEMSI OO product when dryer drum running MEMSI Property & onfidential Page 3 of 8 Tel: , Fax:

5 2 System Setup 2.1 lock iagram hart 1 System Setup lock iagram 2.2 System Setup description Mounting the MEMSI OO module on the washing machine dryer drum. The position & direction is like the hart 1 diagram: ryer drum is in horizontal direction. MEMSI OO module is mounted on the dryer drum outside shell. X/Y plain is in the rotation plane. The OO acceleration output is reading by washing machine MU. Sampling frequency is 2Hz (every 5mS). The acceleration data and associated motor RPM data is sent to P via URT communication. The acceleration data was plotted in the chart below MEMSI Property & onfidential Page 4 of 8 Tel: , Fax:

6 3 Experiment ata Plot 3.1 ata Plot X/Y Plane cc ata Plot in all RPM X-xis cceleration ata Plot vs RPM X-xis eviation ata Plot vs RPM Y-xis cceleration ata Plot vs RPM X/Y Plane eviation ata Plot ll RPM Y-xis eviation ata Plot vs RPM RPM ata Plot, ~1.8K RPM hart 2 cceleration/eviation ata plotting vs RPM, Empty/alanced case Notes for hart: Maxim deviation value in X axis. Maxim deviation value in Y axis. 1 st system harmonic vibration spot in X axis, at about 3RPM. 1 st system harmonic vibration spot in Y axis, at about 2RPM MEMSI Property & onfidential Page 5 of 8 Tel: , Fax:

7 4 :\OO\ \RPM_SN_9318_129.csv X-xis cceleration ata Plot vs RPM - ccx :\OO\ \RPM_SN_9318_129.csv X-xis cceleration mplitude ata Plot - ccx vs Envelop RPM 15 x :\OO\ \RPM_SN_9318_129.csv ata Plot ~1.8K - RPM 1 x :\OO\ \RPM_SN_9318_129.csv X-xis eviation ata Plot vs RPM - Envelop/RPM^2 x Time x 1 4 hart 3 X-xis cceleration/eviation ata plotting vs RPM, Out-Of-alanced case Notes for hart: 1 st system harmonic vibration spot in X axis, at about 32RPM, result the maxim vibration 1 st system vibration wave through spot in X axis, at about 49RPM, result the minimal vibration 2 nd system harmonic vibration spot in X axis, at about 57RPM, result the 2 nd maxim vibration The system is getting stable vibration in much smaller vibration amplitude with RPM increasing, it has passed the system harmonic range that can generate huge OO shocking MEMSI Property & onfidential Page 6 of 8 Tel: , Fax:

8 4 :\OO\ \RPM_SN_9318_129.csv Y-xis cceleration ata Plot vs-rpm ccy :\OO\ \RPM_SN_9318_129.csv Y-xis cceleration mplitude ata- ccy Plot Envelop vs RPM 15 x :\OO\ \RPM_SN_9318_129.csv ata Plot ~1.8K - RPM 1 x :\OO\ \RPM_SN_9318_129.csv Y-xis eviation ata Plot vs - Envelop/RPM^ Time x 1 4 x 1 4 hart 4 Y-xis cceleration/eviation ata plotting vs RPM, Out-Of-alanced case Notes for hart: 1 st system harmonic vibration spot in Y axis, at about 2RPM, result the maxim vibration 1 st system vibration wave through spot in X axis, at about 35RPM, result the minimal vibration 2 nd system harmonic vibration spot in X axis, at about 55RPM, result the 2 nd maxim vibration The system is getting stable vibration in much smaller vibration amplitude with RPM increasing, it has passed the system harmonic range that can generate huge OO shocking MEMSI Property & onfidential Page 7 of 8 Tel: , Fax:

9 4 Summary of experiment The vibration behavior of washing machine dryer drum running (>8RPM) can be simulated as the harmonic motion in all 3-axis. The motion model depends on the actual mechanical suspension structure of the dryer drum. The 2 axes vertical to the drum rotation axis contribute the major OO shock when dryer is running, so monitoring the vibration in the 2 axes can detect & control the OO. The acceleration can directly reflect the vibration model. The vibration amplitude is directly according to the acceleration, the estimated formula is as following: cc RPM x / y 2 eviation x / y The MU of washing machine can monitor the vibration based on the MEMSI accelerometer data output, then take corresponding actions to reduce RPM to re-distribution the loading in the dryer drum, which will effectively reduce the abnormal shocking due to OO happens. The competitive advantage based on the unique thermal technology will make MEMSI accelerometer be suitable for washing machine OO detection application: Monolithic MOS MEMS design: no actual movement part in the sensor, which make MEMSI accelerometer can live in the tough situation with higher reliability, including higher shock survival (5,g), and long term reliability with the whole life of washing machine device. onsistent zero-g offset drift over temperature performance, which gives the constant zero offset reference point. Natural low-pass filter performance to eliminate the higher-frequency noise that carried by the vibration, which could influence the major motion factor for motion detection. igital output interface, which will avoid the electrical noises generated by the dryer motor relay, will make the data transmission digitalized to eliminate the error. Therefore, MEMSI Out-Of-alance module is the best and innovated solution for the OO detection in washing machine dryer MEMSI Property & onfidential Page 8 of 8 Tel: , Fax: