Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
  • G01D5/24471—Error correction
  • G01D5/24476—Signal processing

Definitions

• the present invention can estimate the true position data even if a bit error occurs in the position detection data received from the encoder due to the influence of electromagnetic noise or defective wiring of the encoder by the AC servo driver.
• the present invention relates to a highly reliable method for detecting and estimating a bit error in detected position data of an encoder that can prevent malfunction during rotation.
• Figure 3 shows a schematic circuit diagram of the AC support driver. Take the position control mode as an example. The deviation between the position command and the position feedback is obtained, a speed command is created, the deviation between the speed command and the speed feedback is found, and a current command for driving the motor is created. With this current command, the motor position is adjusted and driven to the command position. Therefore, when the position command is determined, the absolute value and direction of the speed command are determined by position feedback, and the absolute value and direction of the current command are determined by speed feedback.
• the position data detected by the encoder is affected by electromagnetic noise while being sent to the AC servo driver due to leakage of the encoder wiring, etc., and the position data received by the AC servo driver is affected. During operation, bit errors may occur.
• the command position is O x 0000 (the motor is adjusted to the home position. ),
• the current command due to position deviation and speed deviation becomes smaller, fine-position adjustment is performed in the direction of the arrow in Fig. 4 (1).
• Figures 5, 6, and 7 show the experimental results of instantaneous reverse rotation, instantaneous forward rotation, and instantaneous forward and reverse rotation, respectively, due to an encoder detection position data bit error.
• channel 1 is the signal of the position increment value (936 pulses ZV) between encoder sampling periods output from the AC servo driver
• channel 2 is the presence or absence of communication from the encoder of the AC servo driver.
• HI indicates that the communication with the encoder is suspended
• LO indicates that the communication with the encoder is eclipse
• channel 3 indicates the presence or absence of a bit error in the position data output from the AC servo driver.
• j indicates that a bit error has occurred in the position data
• “LO” indicates that there is no bit error in the position data.
• the maximum position change during the sampling period is calculated from the maximum rotation speed during actual use of the motor and the resolution of the encoder.
• the difference between the position data at the current sampling point and the position data at the previous sampling point is calculated. If the difference is larger than the maximum position change amount and the difference between the power encoder resolution and the difference is larger than the maximum position change amount, it is determined that there is a large bit error in the position data at the current sampling time.
• An estimate of the true position data at the time of sampling It is calculated based on the position data at the previous sampling, the speed and sampling cycle of the previous sampling cycle.
• the current and previous position data By checking the difference value and judging that it is at or above a certain level, the current position data is regarded as abnormal data and is not used, and the true position data is estimated. By using this estimated position data as position feedback, large instantaneous vibrations and rapid shocks can be avoided, and the motor can rotate smoothly.
• FIG. 1 is a flowchart showing a bit error detection / estimation method for encoder detected position data according to an embodiment of the present invention.
• FIG. 2 is a graph showing the effect of the present invention.
• FIG. 3 is a schematic diagram of a control loop of an AC support driver.
• Fig. 4 shows an example of the occurrence of a bit error in position data.
• Fig. 5 is a graph of the experimental results showing the instantaneous reversal of the motor due to a bit error in the detected position data of the encoder.
• Figure 7 is a graph of experimental results showing instantaneous forward and reverse rotation of motor due to encoder detected bit error of position data. is there.
• FIG. 1 is a flowchart showing a bit error detection / estimation method for encoder detected position data according to one embodiment of the present invention.
• 1 to 9 represent each step of the flowchart.
• Pos-s1 which is the amount of change (difference) between the position data (pos-b) at the current sampling point and the position data (Pos_a) at the previous sampling point, and the resolution N of the encoder
• pos_s2 which is the amount of change (difference) from pos-s1
• step 5 If “Yes”, it is determined that there is no large bit error in the position data pos—b (step 5).
• step 6 If the determination in step 4 is “No”, it is determined whether Ipos_s2I is equal to or less than pos_1eve1 (step 6).
• step 8 If "No” in step 6, it is determined that there is a large bit error in the position data pos-b, the estimated value pos-bs of the current true position data is calculated, and the position data pos-b is calculated. (Step 8).
• the AC servo driver calculates the maximum position change amount between the sampling cycles based on the maximum rotation speed of the motor in actual use and the resolution of the encoder, and obtains the position data at the time of the current sampling.
• the difference between the position data at the previous sampling time is calculated, and if the difference is larger than the maximum position change amount and the difference between the encoder resolution and the difference is larger than the maximum position change amount, the position data at the current sampling time is calculated. Is determined to have a large bit error, and the estimated value of the real position data at the time of this sampling is calculated from the position data at the previous sampling and the speed and sampling period of the previous sampling period. ing.
• FIG. 2 is a graph showing the effect of the present invention.
• the embodiment of the present invention uses the above-described means, so that even if a bit error occurs in the position detection data received from the encoder due to the influence of the electromagnetic noise of the AC servo driver or the wiring failure of the encoder, It is possible to provide a highly-reliable bit error detection / estimation method of the detected position data of the encoder, which can estimate the true position data and can prevent a malfunction during rotation of the motor.
• the present invention provides an AC servo that creates position and speed feedback from position data detected by an encoder, and creates a command for motor driving from a deviation between a position command and a speed command and a deviation between the position and speed feedback. It is useful as a method for detecting and estimating bit errors in encoder-detected position data, which are generated by the influence of electromagnetic noise while the position data detected by the encoder is sent to the AC servo driver.

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• Engineering & Computer Science (AREA)
• Signal Processing (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Transmission And Conversion Of Sensor Element Output (AREA)
• Control Of Electric Motors In General (AREA)
• Control Of Position Or Direction (AREA)

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Citations (5)

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• 2002
  • 2002-07-03 JP JP2002194539A patent/JP4240195B2/ja not_active Expired - Fee Related
• 2003
  • 2003-06-30 WO PCT/JP2003/008331 patent/WO2004005856A1/ja active Application Filing
  • 2003-07-02 TW TW092118106A patent/TW200401880A/zh unknown

Patent Citations (5)

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