Method for determining a force transmission contact point of an electric clutch actuator

Patent metadata

Field	Value
Publication number	US-12366271-B2
Application number	US-202218714315-A
Country	US
Kind code	B2
Filing date	May 4, 2022
Priority date	May 4, 2022
Publication date	Jul 22, 2025
Grant date	Jul 22, 2025

Abstract

The present invention is directed to a method for determining a force transmission contact point of an actuating element ( 6 ) of an electric clutch actuator which comprises a linear drive assembly configured to linearly move the actuating element ( 6 ) towards a preload plunger ( 10 ) which is linked by a pushrod ( 12 ) to a clutch lever ( 14 ) and to move the pushrod ( 12 ) to turn the clutch lever, characterized by including the steps: monitoring an oscillation of the pushrod ( 12 ) by monitoring the position of the pushrod ( 12 ) and determining in consecutive time periods at least one of a maximum, minimum and centre value of the pushrod position, deriving a measure of non-oscillatory movement of the pushrod ( 12 ) based on a difference between at least one of the respective maximum, minimum and centre values of the pushrod position in a current and at least one of the preceding time periods or based on a difference between a combination of the respective positions in the current and at least one of the preceding time periods; and determining that the actuating element ( 6 ) has reached the force transmission contact point if the measure of non-oscillatory movement of the pushrod exceeds a predetermined threshold value.

First claim

The invention claimed is:

1. A method for determining a force transmission contact point of an actuating element of an electric clutch actuator which comprises a linear drive assembly configured to linearly move the actuating element towards a preload plunger which is linked by a pushrod to a clutch lever and to move the pushrod to turn the clutch lever, including the steps:
monitoring an oscillation of the pushrod by monitoring a position of the pushrod and determining in consecutive time periods at least one of a maximum, minimum and centre value of the pushrod position,
deriving a measure of non-oscillatory movement of the pushrod based on a difference between at least one of the respective maximum, minimum and centre values of the pushrod position in a current and at least one of the preceding time periods or based on a difference between a combination of the respective positions in the current and at least one of the preceding time periods; and
determining that the actuating element has reached the force transmission contact point if the measure of non-oscillatory movement of the pushrod exceeds a predetermined threshold value.

2. The method according to claim 1 , wherein the maximum and the minimum value of the pushrod position are determined in consecutive time periods forming a time series, that for each of the maximum and minimum values the measure of non-oscillatory movement is derived, and that, in the step of determining the force transmission contact point, it is determined that the actuating element has reached the force transmission contact point if at least one of the measures of non-oscillatory movement based on the maximum and minimum values, respectively, exceeds the predetermined threshold value.

3. The method according to claim 2 , wherein each time after determination of the maximum and the minimum value in a current time interval, the time series of the pushrod positions in the current and the preceding time periods is subjected to a discrete high pass filter for each of the maximum and the minimum value by
forming an exponentially weighted moving average over the current and preceding time periods,
forming a difference of averages between the exponentially weighted moving average and a previous exponentially weighted moving average value,
assigning the difference of averages to the previous exponentially weighted moving average value, and
assigning the absolute value of the difference of averages to a discrete high pass filter output value.

4. The method according to claim 3 , wherein the discrete high pass filter output value of each of the maximum and the minimum value of the pushrod position is assigned to the respective measure of non-oscillatory movement.

5. The method according to claim 3 , wherein each time after determination of a maximum and a minimum pushrod position value in a current time period, the discrete high pass filter output value of each of the maximum and the minimum value of the pushrod position is subjected to forming a cumulative sum.

6. The method according to claim 5 , wherein the cumulative sum is formed by adding the current discrete high pass filter output to the preceding cumulative sum, by subtracting a predetermined minimum position resolution value, if the subtraction result is less than zero by setting it to zero, if the cumulative sum is larger than a predetermined saturation value by setting the cumulative sum to the predetermined saturation value, and by setting the preceding cumulative sum equal to the cumulative sum.

7. The method according to claim 5 , wherein the cumulative sum of each of the maximum and the minimum value of the pushrod position is assigned to the respective measure of non-oscillatory movement.

8. The method according to claim 3 , wherein each time after applying the discrete high pass filter its output values are scaled up by multiplying them with a sampling rate used in the measurement acquisition of pushrod positions.

9. The method according to claim 1 , wherein in the step of determining that the actuating element has reached the force transmission contact point it is additionally required that the measure of non-oscillatory movement exceeds the predetermined threshold value over at least a predetermined time interval.

10. The method according to claim 1 , wherein in each time period the maximum and the minimum value of the pushrod position is averaged to determine a centre position of the pushrod, and the centre position of a current time period is compared to the centre position of at least one preceding time period to determine a pushrod velocity, and in that in the step of determining that the actuating element has reached the force transmission contact point it is required that the pushrod velocity exceeds a predetermined threshold velocity value.

11. The method according to claim 10 , wherein:
each time after determination of a centre value of the pushrod position in a current time period, the time series of the centre positions in the current and preceding time periods is subjected to an exponentially weighted moving average, and
a discrete derivative of the consecutive exponentially weighted moving average values of the centre position is calculated to determine the pushrod velocity.

12. The method according to claim 11 , wherein the time series of calculated pushrod velocities in consecutive time periods is subjected to forming an exponentially weighted moving average to determine the pushrod velocity.

13. The method according to claim 6 , wherein the cumulative sum of each of the maximum and the minimum value of the pushrod position is assigned to the respective measure of non-oscillatory movement.

14. The method according to claim 2 , wherein in the step of determining that the actuating element has reached the force transmission contact point it is additionally required that the measure of non-oscillatory movement exceeds the predetermined threshold value over at least a predetermined time interval.

15. The method according to claim 3 , wherein in the step of determining that the actuating element has reached the force transmission contact point it is additionally required that the measure of non-oscillatory movement exceeds the predetermined threshold value over at least a predetermined time interval.

16. The method according to claim 4 , wherein in the step of determining that the actuating element has reached the force transmission contact point it is additionally required that the measure of non-oscillatory movement exceeds the predetermined threshold value over at least a predetermined time interval.

17. The method according to claim 5 , wherein in the step of determining that the actuating element has reached the force transmission contact point it is additionally required that the measure of non-oscillatory movement exceeds the predetermined threshold value over at least a predetermined time interval.

18. The method according to claim 2 , wherein in each time period the maximum and the minimum value of the pushrod position is averaged to determine a centre position of the pushrod, and the centre position of a current time period is compared to the centre position of at least one preceding time period to determine a pushrod velocity, and in that in the step of determining that the actuating element has reached the force transmission contact point it is required that the pushrod velocity exceeds a predetermined threshold velocity value.

19. The method according to claim 3 , wherein in each time period the maximum and the minimum value of the

Assignees

• Ka Group Ag

Inventors

• Chau Jimmy
• Waerp Ole Jonny
• Engman Jimmy

Classifications

• H02K41/02

  Linear motors; Sectional motors · CPC title

• F16D28/00

  Electrically-actuated clutches (arrangements for synchronisation F16D23/02; clutches actuated directly by means of an electromagnet F16D27/00; automatic clutches F16D43/00 - F16D45/00; external control F16D48/00) · CPC title

• F16D2500/7109

  Pulsed signal; Generating or processing pulsed signals; PWM, width modulation, frequency or amplitude modulation · CPC title

• F16D2500/70689

  using maximum or minimum values · CPC title

• F16D2500/3026

  Stroke · CPC title