WO2007085861A1 - Improvements in or relating to the measurement of relative movement - Google Patents
Improvements in or relating to the measurement of relative movement Download PDFInfo
- Publication number
- WO2007085861A1 WO2007085861A1 PCT/GB2007/000297 GB2007000297W WO2007085861A1 WO 2007085861 A1 WO2007085861 A1 WO 2007085861A1 GB 2007000297 W GB2007000297 W GB 2007000297W WO 2007085861 A1 WO2007085861 A1 WO 2007085861A1
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- WIPO (PCT)
- Prior art keywords
- pulse
- pulse train
- input shaft
- input
- output
- Prior art date
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M13/00—Testing of machine parts
- G01M13/02—Gearings; Transmission mechanisms
- G01M13/022—Power-transmitting couplings or clutches
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D48/00—External control of clutches
- F16D48/06—Control by electric or electronic means, e.g. of fluid pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
- F16H59/36—Inputs being a function of speed
- F16H59/46—Inputs being a function of speed dependent on a comparison between speeds
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/02—Rotary-transmission dynamometers
- G01L3/04—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft
- G01L3/10—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating
- G01L3/109—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving measuring phase difference of two signals or pulse trains
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
- G01P3/42—Devices characterised by the use of electric or magnetic means
- G01P3/44—Devices characterised by the use of electric or magnetic means for measuring angular speed
- G01P3/48—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage
- G01P3/481—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
- G01P3/42—Devices characterised by the use of electric or magnetic means
- G01P3/56—Devices characterised by the use of electric or magnetic means for comparing two speeds
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2500/00—External control of clutches by electric or electronic means
- F16D2500/30—Signal inputs
- F16D2500/304—Signal inputs from the clutch
- F16D2500/3041—Signal inputs from the clutch from the input shaft
- F16D2500/30415—Speed of the input shaft
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2500/00—External control of clutches by electric or electronic means
- F16D2500/30—Signal inputs
- F16D2500/304—Signal inputs from the clutch
- F16D2500/3042—Signal inputs from the clutch from the output shaft
- F16D2500/30426—Speed of the output shaft
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2500/00—External control of clutches by electric or electronic means
- F16D2500/30—Signal inputs
- F16D2500/316—Other signal inputs not covered by the groups above
- F16D2500/3166—Detection of an elapsed period of time
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2500/00—External control of clutches by electric or electronic means
- F16D2500/70—Details about the implementation of the control system
- F16D2500/704—Output parameters from the control unit; Target parameters to be controlled
- F16D2500/70422—Clutch parameters
- F16D2500/70426—Clutch slip
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2500/00—External control of clutches by electric or electronic means
- F16D2500/70—Details about the implementation of the control system
- F16D2500/71—Actions
- F16D2500/7107—Others
- F16D2500/7109—Pulsed signal; Generating or processing pulsed signals; PWM, width modulation, frequency or amplitude modulation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
- F16H59/36—Inputs being a function of speed
- F16H59/46—Inputs being a function of speed dependent on a comparison between speeds
- F16H2059/465—Detecting slip, e.g. clutch slip ratio
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Fluid Mechanics (AREA)
- Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Braking Arrangements (AREA)
- Testing Of Engines (AREA)
Abstract
A method of calculating the difference in relative rotational speeds of input and output members (12, 14) of a device (10) configured to permit said members (12, 14) to rotate at different speeds. The method of the present invention permits the calculation of the difference between the rotational speeds of the members (12, 14), hereinafter referred to as the slip, by synchronising the measurement of the input and output member speeds. The present invention rejects any noise caused by cyclic variation of the input member speed.
Description
Improvements in or Relating to the Measurement of Relative Movement
The present invention relates to the measurement of relative movement between components. Particularly, though not exclusively, the present invention relates to the measurement of slip between the rotatable input and output members of a device provided between the members and which permits the members to rotate at different speeds. In such an embodiment, the present invention may relate to the measurement of slip between the input and output shafts of a clutch mechanism.
In an automated transmission system having at least one clutch, closed loop slip control is an important part of accurate clutch handling. During in gear operation, small slips can be maintained by precise control of clutch torque capacity. The presence of the clutch slip allows control algorithms of the transmission system to accurately adapt to the individual characteristics of the clutch, and maintains the clutch in a constant state of readiness for dynamic events such as, for example, gear shifts.
In present transmission systems the amount of slip between the input and output members of a clutch is measured by monitoring the rotational speed of the members and performing a subtraction. The figure thus obtained can then be used as an input signal to a clutch controller. The rotational speeds are typically obtained by measuring the period of toothed wheels provided on the input and output shafts respectively.
In order to maximise the efficiency of a transmission system it is highly desirable to control the clutch slip to a relatively low value, typically less than 30 rpm. However, the cyclic variation in the speed produced by an engine can vary to a much greater degree than this. In the case of a turbocharged diesel engine the cyclic variation can be in the region of 150 rpm. It will thus be appreciated that the signal to noise ratio of a clutch controller input signal derived by the subtraction method described above can be very poor and hence lead to clutch control difficulties.
According to a first aspect of the present invention there is provided a method of calculating the difference in relative rotational speeds of input and output members of a
device configured to permit said members to rotate at different speeds, the method comprising the steps of: providing a sensor operable to observe the rotation of the input member and provide an output in the form of a pulse train; providing a sensor operable to observe the rotation of the output member and provide an output in the form of a pulse train; providing a free running timer; providing a processor arranged to receive the pulse train outputs from the sensors and an input from the timer; assigning a time to a first pulse of the input member pulse train; assigning a time to a second pulse of the input member pulse train, said second pulse being after said first pulse; assigning a time to a first pulse of the output member pulse train, said first output member pulse preceding the first pulse of the input member pulse train; assigning a time to a second pulse of the output member pulse train, said second output member pulse being after the second pulse of the input member pulse train; assigning a time to any output member pulses occurring between said first and said second output member pulses and counting any such pulses; and utilising the assigned times and pulse counts together with data relating to the device having the rotatable input and output members to calculate the input member rotational speed, the output member rotational speed and any difference therebetween.
The method of the present invention permits the calculation of the difference between the rotational speeds of the members, hereinafter referred to as the slip, by synchronising the measurement of the input and output member speeds. The present invention rejects any noise caused by cyclic variation of the input member speed.
The method preferably includes the step of calculating an input member period by subtracting the first input member pulse time from the second impulse member time. The method may include the step of calculating an input speed constant value based upon the free running timer speed and a number representative of features of the input member sensor which generate the pulse train. For example, the sensor may include a toothed wheel fixed for rotation with the input member. In such an embodiment, said number may
correspond to the number of teeth on the wheel. Similarly, the method may include the step of calculating an output speed constant value based upon the free running timer speed and a number representative of features of the output member sensor which generate the pulse train. For example, the sensor may include a toothed wheel fixed for rotation with the output member. In such an embodiment, said number may correspond to the number of teeth on the wheel.
The method may include the step of calculating a first fraction of the input member period, said first fraction corresponding to the portion of the input member period between the time assigned to the first pulse of the input member pulse train and the time assigned to the first pulse of the output member pulse train occurring after said first pulse of the input member pulse train. The method may include the step of calculating a second fraction of the input member period, said second fraction corresponding to the portion of the input member period between the time assigned to a pulse of the output member pulse train immediately preceding the second pulse of the input member pulse train and the time assigned to said second pulse of the input member pulse train.
Preferably the recordal of times assigned to the pulses and the counted pulses is made in response to interrupt service routines of the processor. The recordal of the times of the first and second pulses of the input member pulse train are preferably made by an interrupt service routine of the processor which is triggered upon the assignment of the time to the second pulse of the input member pulse train. The calculation of the input shaft period is preferably also made by said interrupt service routine of the processor which is triggered upon the assignment of the time to the second pulse of the input member pulse train.
The recordal of the times of the pulses of the output member pulse train and the counted pulses is preferably made by an interrupt service routine of the processor which is triggered upon the assignment of the time to the second pulse of the output member pulse train.
The calculation of the input shaft rotational speed, the output shaft rotational speed and any difference therebetween may undertaken at a loop call rate which is independent of the processor interrupt service routines. The loop call rate may be variable so as to take into account the service requirements of the device having the input and output members.
In a preferred embodiment the device configured to permit said members to rotate at different speeds is a clutch mechanism and the input and output members are shafts.
According to a second aspect of the present invention there is provided a method of calculating the difference in relative linear speeds of input and output members of a device configured to permit said members to move linearly at different speeds, the method comprising the steps of: providing a sensor operable to observe the linear movement of the input member and provide an output in the form of a pulse train; providing a sensor operable to observe the linear of the output member and provide an output in the form of a pulse train; providing a free running timer; providing a processor arranged to receive the pulse train outputs from the sensors and an input from the timer; assigning a time to a first pulse of the input member pulse train; assigning a time to a second pulse of the input member pulse train, said second pulse being after said first pulse; assigning a time to a first pulse of the output member pulse train, said first output member pulse preceding the first pulse of the input member pulse train; assigning a time to a second pulse of the output member pulse train, said second output member pulse being after the second pulse of the input member pulse train; assigning a time to any output member pulses occurring between said first and said second output member pulses and counting any such pulses; and utilising the assigned times and pulse counts together with data relating to the device having the input and output members to calculate the input member linear speed, the output member linear speed and any difference therebetween.
The method of the second aspect may, for example, be utilised in connection with linear feed arrangements of the type found on machine tools.
According to a third aspect of the present invention there is provided a method of calculating the difference in relative rotational position of input and output members of a
device having a compliant coupling to permit said members to rotate and move angularly with respect to one another, the method comprising the steps of: providing a sensor operable to observe the rotational position of the input member and provide an output in the form of a pulse train; providing a sensor operable to observe the rotational position of the output member and provide an output in the form of a pulse train; providing a free running timer; providing a processor arranged to receive the pulse train outputs from the sensors and an input from the timer; assigning a time to a first pulse of the input member pulse train; assigning a time to a second pulse of the input member pulse train, said second pulse being after said first pulse; assigning a time to a first pulse of the output member pulse train, said first output member pulse preceding the first pulse of the input member pulse train; assigning a time to a second pulse of the output member pulse train, said second output member pulse being after the second pulse of the input member pulse train; assigning a time to any output member pulses occurring between said first and said second output member pulses and counting any such pulses; and utilising the assigned times and pulse counts together with data relating to the device having the input and output members to calculate the input member rotational position, the output member rotational position and any difference therebetween.
The method of the third aspect may be utilised to measure the amount of twist or angular displacement, as opposed to slip, between the input and output members. This data could, for example, be utilised to estimate the torque transmitted between the input and output members. The method may, for example, be utilised in connection with vehicle steering systems.
Features of the first aspect of the present invention may equally apply to the methods described with reference to the second and third aspects.
An embodiment of present invention will now be described with reference to the accompanying drawings in which:
Figure 1 shows a schematic representation of a system according to the present invention; and
Figure 2 shows a representation of clutch input and output member pulse train and time line measurements.
Referring firstly to figure 1 there is shown a clutch mechanism generally designated 10. The clutch mechanism 10 is provided between a clutch input member or shaft 12 and a clutch output member or shaft 14. The clutch input shaft 12 extends from an engine or motor (not shown), while the clutch output shaft 14 extends to a transmission arrangement such as a gearbox (not shown). In the embodiment shown the clutch mechanism 10 is of the multi-plate type and includes two clutch plates 16 which are connected to the clutch output shaft 14, and two pressure plates 18 connected to the clutch input shaft 12. The configuration of a twin plate clutch is given by way of example only and is not intended to be limiting upon the scope of protection sought.
The clutch mechanism 10 is provided with actuation means 20 operable to move the clutch and pressure plates 16, 18 between a fully engaged state and a fully disengaged state. The actuation means 20 is also operable to move the clutch and pressure plates 16,18 to a partially engaged or disengaged position between the fully engaged and disengaged positions whereupon clutch slip is experienced. The actuation means 20 is provided with an input 21 through which clutch engagement/disengagement commands can be supplied, for example from a gear shift control system (not shown).
The clutch input and output shafts 12,14 are each provided with a speed sensor generally designated 22 and 24 respectively. The speed sensors 22,24 include a wheel 26,28 fixed to the clutch input and output shaft 12,14 respectively, and a sensor element 30,32 arranged to monitor the movement of the wheel 26,28. The wheels 26,28 and sensors 30,32 co-operate to generate pulse train outputs 34,36 as a result of the rotation of input and output shafts 12,14 respectively. In a preferred embodiment the wheels 26,28 are provided with a known number of equidistantly spaced teeth. It will be appreciated that the wheels 26,28 may be provided with other equidistantly spaced features which can be monitored by an appropriately configured sensor to produce the required square wave pulse train outputs 34,36.
The speed sensors 22,24 are connected to a microprocessor 38. The pulse train outputs 34,36 of the speed sensors 22,24 are shown as being supplied directly to the microprocessor 38, however it will be understood that appropriate input protection circuitry will be provided between the speed sensors 22,24 and the microprocessor 38. The microprocessor 38 is further provided with a memory 40 and a high speed, free running timer 42. The timer 42 is provided so that the microprocessor 38 can assign a time to events monitored by the speed sensors 22,24. The memory 40 is provided with static data relating to the clutch mechanism 10 which, as will be described below, is required to calculate the clutch slip, as well as being able to store time data relating to the speed sensor monitored events. For example, the static data contained in the memory 40 may include the number of teeth or other such monitorable features of the clutch input and output shaft wheels 26,28.
The microprocessor 38 is provided with an output 44 which is connected to the clutch actuation means 20, and an input 46 via which information relating to a desired or required clutch slip value can be specified. The input may, for example, be connected to a gear shift control system. It will be appreciated that the closed loop control system is thus provided with the microprocessor 38 being operable to monitor the relative speeds of the clutch input and output shafts 12,14 and thereby determine the amount of slip therebetween, compare the actual slip to the desired slip supplied to the microprocessor 38 via the input 46, and, if required, supply commands to the clutch actuation means 20 via the output 44 to alter the interaction of the clutch plates 16 and pressure plates 18 and alter the amount of clutch slip so that it is closer to or reaches the desired slip value supplied to the microprocessor 38.
Referring now to figure 2 there is shown a representation of the speed sensor pulse train outputs 34,36, together with upper and lower timeline plots 48,50 which illustrate the spacing and overlap of certain pulse train output events. The upper pulse train 34 corresponds to the output from the speed sensor 22 associated with the clutch mechanism input shaft 12, while the lower pulse train 36 corresponds to the output from the speed sensor 24 associated with the clutch mechanism output shaft 14. As will be readily appreciated, the pulse trains 34,36 are not in phase with one another and hence a degree of slip is present in the clutch mechanism 10 observed by the sensors 22,24.
In the instance where the clutch mechanism 10 is provided between an engine and a transmission, the clutch input shaft 12 may be directly connected to the engine crank shaft and the clutch output shaft 14 may be directly connected to the transmission input shaft. It will thus be understood that measurement of the rotational speed of the clutch input shaft 12 will thus correspond to measurement rotational speed of the engine.
The microprocessor 38 is initially configured to monitor only the pulse train 36 of clutch output shaft speed sensor 24. The microprocessor 38 monitors the rising edge 52 of the pulse train 36 and assigns a time t(outputl) supplied by the timer 42 to this event. Time t(outputl) is stored in the memory 40. The microprocessor 38 continues to monitor pulse train output 36 and assigns each rising edge 52 time t(outputl) and successively overwrites previously stored t(outρutl) times stored in the memory 40. This monitoring and overwriting cycle continues until the microprocessor 38 commences monitoring the pulse train 34 of the clutch input shaft speed sensor 22.
In monitoring the pulse train 34 of the clutch input shaft speed sensor 22, the microprocessor 38 monitors the rising edges 54 of the pulse train 34 and assigns a time t(enginel) to the first rising edge 54. The term "engine" is used in connection with the monitoring of the clutch input shaft speed as the input shaft 12 is, as described above, directly connected to an engine. The microprocessor 38 continues to monitor the rising edges 54 of the clutch input shaft pulse train 34 until a desired number of rising edges 54 have been observed. In the embodiment shown the microprocessor 38 observes two successive rising edges 54 after the t(enginel) rising edge, and assigns the second of the two the time t(engine2). The observation of two successive rising edges 54 of the clutch input shaft pulse train 34 is given by way of example only and this number may vary dependent upon a number of factors relating to the configuration and performance of the transmission system that the clutch mechanism 10 is incorporated into.
Once the monitoring of the clutch input shaft pulse train 34 has commenced, the microprocessor continues to monitor the clutch output shaft pulse train 36. Rising edges 52 of the pulse train 36 observed after the t(enginel) rising edge 54 and before the t(engine2) rising edge 54 are assigned times t(output2) and t(output3) respectively. The first rising edge 52 observed after the t(engine2) rising edge 54 is assigned time t(output4). The rising
edges 52 observed and accumulated between the t(enginel) and t(engine2) time measurements are assigned a count number indicated by abbreviation cnt in figure 2.
Upon assignment of time t(engine2) to a rising edge 54 of the clutch input shaft pulse train 34 the microprocessor executes an interrupt service routine causing a copy of times t(enginel) and t(engine2) to be written to the memory 40, as well as deriving and storing in the memory a value for the engine period. The engine period value is derived by the following calculation:
EnginePeriod = t(engine2) - t(enginel)
The engine period is illustrated by the shaded block 56 on upper time line 48 of figure 2.
Upon assignment of time t(output4) to a rising edge 52 of the clutch output shaft pulse train 36, a further interrupt service routine is executed and a copy of times t(outputl), t(output2), t(output3) and t(output4) written to the memory 40, along with the count value cnt. The following calculations can then be made at desired loop call rate:
EngineSpdConstant = (FreeRunningTimerFrequency*60)/InputShaftWheelTeeth
OutputShaftSpdConstant= (FreeRunningTimerFrequency*60)/OutputShaftWheelTeeth
Fractionl = (t(output2) - t(enginel))/(t(output2)-t(outputl))
Fraction2 = (t(engine2)-t(output3))/(t(output4)-t(output3))
EngineSpeed=(EngineSpeedConstant*NumberOfPulsesAccumulated)/EnginePeriod
OutputSpeed=(OutputShaftSpeedConstant* (Fraction 1 +Fraction2+cnt))/EnginePeriod
ClutchSlip = EngineSpeed - OutputSpeed
The values Fraction 1 and Fraction2 are illustrated by hatched blocks 58 and 60 on the lower time line 50 of figure 2. Fractionl 58 corresponds to the portion of the engine period between times t(enginel) and t(output2), while Fraction2 60 corresponds to the portion of the engine period between times t(output3) and t(engine2).
The method of the present invention is particularly suited to the measurement of clutch slip in automated and dual clutch vehicle transmissions. It will be appreciated that the method may be used in connection with other devices having rotatable input and output shafts which are able to rotate at different speeds relative to one another. It is envisaged that the method of the present invention may also be employed in connection with such devices as, for example, viscous couplings and differential gear arrangements. The method may be employed with devices of the type described which are utilised outside of the automotive field.
The embodiment of the present invention described with reference to the accompanying figures relates to the measurement of slip between rotatable input and output shafts of a clutch system. The method of the present invention may equally be applied to the measurement of differences between the movement of input and output members of a linear system. Furthermore, the method of the present invention may be utilised in connection with a compliant coupling provided between rotatable input and output members to measure the angular displacement or twist between the members.
Claims
1. A method of calculating the difference in relative rotational speeds of input and output shafts of a clutch device, the method comprising the steps of: providing a sensor operable to observe the rotation of the input shaft and provide an output in the form of a pulse train; providing a sensor operable to observe the rotation of the output shaft and provide an output in the form of a pulse train; providing a free running timer; providing a processor arranged to receive the pulse train outputs from the sensors and an input from the timer; assigning a time to a first pulse of the input shaft pulse train; assigning a time to a second pulse of the input shaft pulse train, said second pulse being after said first pulse; assigning a time to a first pulse of the output shaft pulse train, said first output shaft pulse preceding the first pulse of the input shaft pulse train; assigning a time to a second pulse of the output shaft pulse train, said second output shaft pulse being after the second pulse of the input member pulse train; assigning a time to any output shaft pulses occurring between said first and said second output shaft pulses and counting any such pulses; and utilising the assigned times and pulse counts together with data relating to the clutch device having the input and output shafts to calculate the input shaft rotational speed, the output shaft rotational speed and any difference therebetween.
2. A method as claimed in claim 1 wherein the calculation step includes the step of calculating an input shaft period by subtracting the first input shaft pulse time from the second input shaft pulse time.
3. A method as claimed in claim 1 or claim 2 wherein the calculation step includes the step of calculating a input speed constant value based upon the free running timer speed and a number representative of features of the input shaft sensor which generate the pulse train.
4. A method as claimed in claim 3 wherein the input shaft sensor includes a toothed wheel fixed for rotation with the input shaft and said number corresponds to the number of teeth on the wheel.
5. A method as claimed in any preceding claim wherein the calculation step includes the step of calculating an output speed constant value base upon the free running timer speed and a number representative of features of the output shaft sensor which generate the pulse train.
6. A method as claimed in claim 5 wherein the output shaft sensor includes a toothed wheel fixed for rotation with the output shaft and said number corresponds to the number of teeth on the wheel.
7. A method as claimed in any of claims 3 to 6 when dependent upon claim 2, wherein the calculation step includes the step of calculating a first fraction of the input shaft period, said first fraction corresponding to the portion of the input shaft period between the time assigned to the first pulse of the input shaft pulse train and the time assigned to the first pulse of the output shaft pulse train occurring after said first pulse of the input shaft pulse train.
8. A method as claimed in any of claims 3 to 7 when dependent upon clam 2 wherein the calculation step includes the step of calculating a second fraction of the input shaft period, said second fraction corresponding to the portion of the input shaft period between the time assigned to a pulse of the output shaft pulse train immediately preceding the second pulse of the input shaft pulse train and the time assigned to said second pulse of the input shaft pulse train.
9. A method as claimed in any preceding claim wherein the recordal of times assigned to the pulses and the counted pulses is made by interrupt service routines of the processor.
10. A method as claimed in claim 9 wherein the recordal of the times of the first and second pulses of the input shaft pulse train is made by an interrupt service routine of the processor which is triggered upon the assignment of the time to the second pulse of the input shaft pulse train.
11. A method as claimed in claim 10 when dependent upon claim 2 wherein the calculation of the input shaft period is made by said interrupt service routine of the processor which is triggered upon the assignment of the time to the second pulse of the input shaft pulse train.
12. A method as claimed in any of claims 9 to 11 wherein the recordal of the times of the pulses of the output shaft pulse train and the counted pulses is made by an interrupt service routine of the processor which is triggered upon the assignment of the time to the second pulse of the output shaft pulse train.
13. A method as claimed in any of claims 9 to 12 wherein the calculation of the input shaft rotational speed, the output shaft rotational speed and any difference therebetween is undertaken at a loop call rate which is independent of the processor interrupt service routines.
14. A method as claimed in claim 13 wherein the loop call rate is variable.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE112007000265T DE112007000265T5 (en) | 2006-01-30 | 2007-01-29 | Improvement in or in relation to the measurement of a relative movement |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0601847.7 | 2006-01-30 | ||
| GBGB0601847.7A GB0601847D0 (en) | 2006-01-30 | 2006-01-30 | Improvements in or relating to slip measurement |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2007085861A1 true WO2007085861A1 (en) | 2007-08-02 |
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ID=36061127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/GB2007/000297 WO2007085861A1 (en) | 2006-01-30 | 2007-01-29 | Improvements in or relating to the measurement of relative movement |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE112007000265T5 (en) |
| GB (1) | GB0601847D0 (en) |
| WO (1) | WO2007085861A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104730277A (en) * | 2015-04-01 | 2015-06-24 | 武汉理工通宇新源动力有限公司 | Gearbox rotating speed measuring method |
| CN105510026A (en) * | 2015-12-10 | 2016-04-20 | 内蒙古久和能源装备有限公司 | Wind turbine generator system shaft coupling skidding fault detection apparatus and method |
| WO2017174651A1 (en) | 2016-04-07 | 2017-10-12 | Voith Patent Gmbh | Torque limiting coupling |
| CN113446167A (en) * | 2021-08-09 | 2021-09-28 | 中国船舶重工集团海装风电股份有限公司 | Wind power coupling slip fault early warning method based on big data analysis |
| EP4008920A1 (en) | 2020-12-03 | 2022-06-08 | Voith Patent GmbH | Torque limiting coupling |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102022204852A1 (en) | 2022-05-17 | 2023-11-23 | Zf Friedrichshafen Ag | Device with two coupled shaft sections and with a detection device for detecting and determining angle information of the shaft sections |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4513627A (en) * | 1982-06-08 | 1985-04-30 | Nippon Soken, Inc. | Torque detector |
| US4979398A (en) * | 1989-09-28 | 1990-12-25 | Allied-Signal Inc. | Torque measurement circuit |
| DE4320834A1 (en) * | 1992-06-26 | 1994-04-14 | Andreas Prof Dr Ing Seeliger | Torque measurement on shaft using breadth of teeth or holes in discs - employing two discs whose signals are compared to time of emission for compensation of distribution errors |
-
2006
- 2006-01-30 GB GBGB0601847.7A patent/GB0601847D0/en not_active Ceased
-
2007
- 2007-01-29 DE DE112007000265T patent/DE112007000265T5/en not_active Withdrawn
- 2007-01-29 WO PCT/GB2007/000297 patent/WO2007085861A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4513627A (en) * | 1982-06-08 | 1985-04-30 | Nippon Soken, Inc. | Torque detector |
| US4979398A (en) * | 1989-09-28 | 1990-12-25 | Allied-Signal Inc. | Torque measurement circuit |
| DE4320834A1 (en) * | 1992-06-26 | 1994-04-14 | Andreas Prof Dr Ing Seeliger | Torque measurement on shaft using breadth of teeth or holes in discs - employing two discs whose signals are compared to time of emission for compensation of distribution errors |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104730277A (en) * | 2015-04-01 | 2015-06-24 | 武汉理工通宇新源动力有限公司 | Gearbox rotating speed measuring method |
| CN104730277B (en) * | 2015-04-01 | 2017-10-03 | 武汉理工通宇新源动力有限公司 | A kind of gearbox rotating speed measurement method |
| CN105510026A (en) * | 2015-12-10 | 2016-04-20 | 内蒙古久和能源装备有限公司 | Wind turbine generator system shaft coupling skidding fault detection apparatus and method |
| WO2017174651A1 (en) | 2016-04-07 | 2017-10-12 | Voith Patent Gmbh | Torque limiting coupling |
| EP4008920A1 (en) | 2020-12-03 | 2022-06-08 | Voith Patent GmbH | Torque limiting coupling |
| WO2022117260A1 (en) | 2020-12-03 | 2022-06-09 | Voith Patent Gmbh | Torque limiting coupling |
| CN113446167A (en) * | 2021-08-09 | 2021-09-28 | 中国船舶重工集团海装风电股份有限公司 | Wind power coupling slip fault early warning method based on big data analysis |
| CN113446167B (en) * | 2021-08-09 | 2022-10-11 | 中国船舶重工集团海装风电股份有限公司 | Wind power coupling slip fault early warning method based on big data analysis |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0601847D0 (en) | 2006-03-08 |
| DE112007000265T5 (en) | 2009-01-08 |
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