FR2848607A1 - Internal combustion motor controlling method, involves controlling functioning of activator using one position measure signal of mobile unit if functioning of direct command is disrupted - Google Patents

Abstract

The process involves elaborating a command signal of the position of an activator mobile unit (3) according to a instruction signal (C) and position measure signals (P1,P2) of mobile unit of an activator (1). The functioning of activator is controlled using one of the position measure signals of the mobile element if the functioning of a direct command in which direct elaboration of command signal from the instruction signal is disrupted. An Independent claim is also included for a device controlling and commanding an activator of regulation of flow in a circulation duct of a fluid.

Description

i

  Method for monitoring and controlling a flow control actuator and associated device.

  The present invention relates to a method for monitoring and controlling a flow control actuator in a fluid circulation pipe, and an associated device.

  The internal combustion engines are associated with elements for performing elementary functions of the actuator and sensor type, to control and command the internal combustion engine. It is desired to be able to control and command the internal combustion engine in a precise manner, in particular to make it possible to respond to the instructions of a driver, but also to improve the operation of elements associated with the internal combustion engine, such as purification means gases whose operation depends on a composition of the exhaust gases emitted by the internal combustion engine.

  The elements allowing the realization of elementary functions can be in the form of sensors or actuators. The actuators can themselves be controlled. In this case, an actuator comprises a movable element and sensors of the position of this movable element for regulating the position of the latter. However, in certain cases, there may appear disturbances in the operation of the actuator in general, and in particular disturbance of the operation of the sensors associated with the actuator. Control and command of the internal combustion engine as a whole may be disturbed.

  The present invention relates to a method for monitoring and controlling a flow control actuator in a fluid circulation pipe, allowing the detection of disturbances in the operation of the actuator and making it possible to compensate for these disturbances. The present invention also relates to a method for controlling and commanding a flow control actuator, allowing an improvement in the control and command of the actuator in order to improve the control and command of a device. with which the actuator is associated.

  The present invention also relates to a method for controlling and controlling a flow control actuator, which can be implemented in a simple manner and without prohibitive overhead, and which can be associated with a predetermined control method without requiring complex adaptation.

  In such a method of monitoring and controlling a flow control actuator in a fluid circulation pipe, in a controlled control mode, a signal for controlling the position of a movable element of the control is produced. the actuator as a function of a setpoint signal and at least one signal for measuring the position of the movable element, the operation of the actuator is checked from at least one signal for measuring the position of the movable element, and, if disturbances in the operation of the actuator are detected, it switches to a direct control mode in which control signals are generated directly from a setpoint signal.

  Switching to a direct control mode allows the actuator to be controlled in a "degraded" mode, but allowing stabilization of the control and control of the actuator. Preferably, it switches to direct control mode temporarily, as long as disturbances in the operation of the actuator are detected.

  In one embodiment, the position of the movable element is measured using the two position sensors, and the operation of the actuator is checked by comparing the measurement signals of the two position sensors. The use of two position sensors makes it possible to detect disturbances in the operation of the actuator, for example by detecting diverging measurement signals from the two position sensors.

  In one embodiment, it switches to direct control mode when the difference variation, determined as the difference between on the one hand the difference at a given time between the measurement signals of the two sensors and on the other hand the difference at a previous instant between the measurement signals of the two sensors, is greater than a determined threshold.

  Advantageously, it switches to direct control mode 15 when the difference in difference is greater than a determined threshold during a determined time interval. This makes it possible to avoid switching to a direct control mode for a one-time threshold overrun which is not representative of a real disturbance in the operation of the actuator.

  In one implementation mode, it returns to regulated control mode if the difference variation becomes less than a determined threshold.

  In one implementation mode, one returns to regulated control mode if the absolute value of the difference between the measurement signals of the two sensors is less than a determined threshold. When switching from a direct control mode to a regulated control mode, it is preferably possible to maintain a constant control instruction for a determined period of time, in order to initialize regulation parameters. Indeed, the regulated control of an actuator may require taking into account data, such as the speed and acceleration of the movable element, which must be determined from several position measurements made at earlier times.

  In one embodiment, it switches to direct control mode if the absolute value of the difference between the setpoint signal and at least one signal for measuring the position of the movable element, is greater than a determined threshold.

  In one embodiment, the absolute value 10 of the difference between the setpoint signal and at least one signal measuring the position of the movable element detected during a determined time interval is integrated, and the mode is switched to direct command if the integration result is above a determined threshold.

  In one mode of implementation, one returns to regulated control mode after a determined period of time.

  In one implementation mode, when switching from a direct control mode to a regulated control mode, a detection of disturbances is inhibited based on the difference between the setpoint signal and at least one position measurement signal of the movable element 20.

  Advantageously, the method can be implemented for the command and control of an air intake butterfly in an intake pipe allowing the air supply to the combustion chambers of an internal combustion engine.

  The invention also relates to a device for monitoring and controlling a flow regulation actuator in a fluid circulation pipe, in particular a butterfly for controlling the air flow admitted into an internal combustion engine, the actuator comprising at least one movable element and a position sensor of the movable element, the device comprising a module for controlling the position of the movable element as a function of a setpoint signal and at least one signal for measuring the position of the movable element. The control device further comprises a selection module capable of controlling the operation of the actuator from at least one signal for measuring the position of the mobile element, and capable of selecting a direct control module provided to generate control signals directly from a setpoint signal if disturbances in the operation of the actuator are detected. The selection module can also select a direct control module according to a setpoint signal.

  The present invention and its advantages will be better understood on studying the detailed description of an embodiment taken by way of nonlimiting example and illustrated by the appended figures, in which - Figure 1 is a schematic view of a flow control actuator and an associated control and command device; FIG. 2 represents a first graph illustrating measurement signals supplied by position sensors of a movable element of the actuator according to FIG. 1 and a second graph illustrating a signal obtained from measurement signals of the first graph ; FIG. 3 represents a first graph illustrating signals for measuring the position of a movable element of an actuator 25 and a second graph illustrating a signal obtained from the measurement signal of the first graph.

  In FIG. 1, a flow control actuator, referenced 1 as a whole and delimited by dotted lines, is arranged in a pipe 2 for circulation of a fluid, from left to right 30 in the figure, as shown schematically by small arrows F. The actuator is in the form of a butterfly or flap 3, mounted for rotation about an axis 4 perpendicular to a main direction of flow of the fluid in the pipe 2. The flap 3 can be oriented between an open position of maximum flow 4a o the shutter 3 is aligned with the main direction of flow, and a closed position of minimum flow 4b o the shutter 3 is substantially perpendicular to the main direction of flow. Stops 8, 9 are provided to prevent movement of the flap 3 beyond the open 4a and closed 4b positions.

  The position of the flap 3 can be controlled using a motor 5 shown diagrammatically and a control device 6 for the motor 5. The motor 5 is advantageously an electric motor of the direct current type.

  The control device 6 comprises control modules, here three in number, and comprising a regulated control module 10, a first direct control module 11, and a second direct control module 12. The control device 6 comprises also a selection module 13, making it possible to select a particular control mode by selectively activating the regulated control module 10, the first direct control module 11 or the second direct control module 12.

  The selection module 13 receives as input the setpoint signal C of the position of the shutter 3 and of the measurement signals Pi and P2 coming from a first and from a second sensor, not shown for reasons of clarity of the drawings, and each supplying a signal for measuring the position of the flap. From the setpoint signal C and the first and second measurement signals Pi, P2, the selection module 13 checks the operation of the actuator 1 to determine if there are disturbances in the operation of the actuator and selects in consequence one of the regulated or direct control modules 10 to 12.

  The regulated control module 10 makes it possible to control the position of the flap 3 of the actuator 1 in regulated mode. 5 The regulated control module 10 receives as input a setpoint position C for the shutter 3 and the first signal Pi for measuring the position of the shutter 3 and generates a control signal S transmitted to the actuator via a link 14.

  The first direct control module 11 receives as input 10 only the setpoint signal C from which it generates a control signal S. Likewise, the second direct control module 12 receives as input only the setpoint signal C and works out from the latter a control signal S. The first and second direct control modules 11, 12 15 can be selected for cases of disturbance of the operation of the different actuator. For example, the first direct control module 11 can be selected in the case of the detection of faults in the position sensors of the shutter 3. The second direct control module 12 can be provided for controlling the actuator 1 in the case of detection of oscillations of the movable flap 3. FIGS. 2 and 3 are described below while retaining the references used for FIG. 1.

  In FIG. 2, a first graph, located in the upper part of the figure, comprises an abscissa axis on which time is plotted and a y axis on which plots of setpoint C and position measurement signals Pi are plotted , P2.

  A setpoint signal C is shown in dotted lines and is substantially constant over time. A first position signal Pi is shown in dashed lines, and a second position measurement signal P2 is shown in solid lines.

  The second graph, located in the lower part of FIG. 2, presents an abscissa axis, on which time is plotted and a ordinate axis on which is plotted a signal i (P2-PI) subsequently named variation of difference, determined by the selection module 13 and used for the detection of a malfunction of one of the sensors from the measurement signals Pl, P2. The difference variation A (P2-P1) is shown in solid lines. The time scale of the second graph corresponds to that of the first graph, to allow simultaneous reading of the two graphs.

  The difference in difference A (P2-Pl) is defined as the difference between on the one hand, the difference at a given instant between the second measurement signal P2 and the first measurement signal Pl and 15 on the other hand the difference at a previous instant between the second measurement signal P2 and the first measurement signal Pi. The previous instant and the given instant may correspond to a digital sampling of the data, and may be separated by a sampling duration A (P2 - Pi ) = (P2 - Pl), - (P2 Pl) il Up to an instant Tl, the measurement signals Pi, P2 are substantially equal to each other and to the position setpoint C. The difference variation A (P2-PI ) is substantially zero.

  From the instant Tl, the first signal Pi deviates from the second signal P2. The first signal Pi drops to the value 0 corresponding to a zero voltage delivered by the associated measurement sensor. Since the regulation is disturbed, the signal P2, corresponding to the effective position of the shutter 3, indicates that the latter deviates from the setpoint position C. The difference variation A (P2-Pl) increases and exceeds a tilting threshold If represented by fine dotted lines at an instant T2. The variation in difference A (P2-Pl) remains greater than the threshold Si between the instant T2 and a following instant T3, separated from the instant 5 T2 by a determined duration. Consequently, as two conditions are fulfilled, that is to say that the difference variation A (P2-Pl) is greater than a first threshold Si and remains greater than this threshold for a determined period, the selection module 13 causes a switching to direct control mode by selecting the first direct control module 11.

  Then, due to the end of the disturbance which appeared on the first sensor, the first signal Pi ceases to decrease and gradually joins the second signal P2. The difference variation A (P2Pi) ceases to increase, then decreases until it crosses a second threshold S2 S2, here fixed at 0, becoming less than this second threshold S2 from an instant T4. The selection module 13 sends a signal corresponding to the first direct control module 11 which freezes the command from time T4, and this for a determined duration, until time T5. At the end of this period, the selection module 13 then causes the switch to regulated control mode by selecting the regulated control module 10 again.

  The time interval during which the command is frozen is intended to re-initialize variables of the regulated control module 10 which may be erroneous at time T4 due to the disturbance. 25 These quantities will in particular be the acceleration and the speed of movement of the shutter 3 which are generally obtained from signals of successively earlier positions of the shutter 3.

  Furthermore, between times T3 and T5, the control of the position of the flap 3 is not regulated, that is to say that the effective position of the flap 3 is not taken into account in order to generate a signal. command S of the actuator 1. As a result, there may be an error between the position setpoint C and the actual position of the shutter 3. This appears on the first graph between times T3 and T5.

  To eliminate an initial error in the position control 5 of the shutter 3, it can be provided, as illustrated in the first graph, that at the instant T5 of resumption of the regulated control and selection of the regulated control module 10, a position setpoint C is reset to the value of the current position of shutter 3, before quickly reaching the desired position setpoint C actually 10.

  A disturbance which can lead to an erroneous position signal, like the first signal Pi is a micro-cut. By micro-interruption is meant an interruption of a measurement signal intervening on the position measuring chain of the shutter 3, and resulting in an interruption of current transmission and a drop in the voltage of an associated measurement signal.

  In the case where a micro-interruption appearing on a position sensor of the shutter 3 is prolonged for a significant duration, the variation of difference A (P2-P1) may become small, or even less than the second determined threshold S2, while the micro-interruption n is not over. To obviate this drawback, provision can be made to add a second criterion allowing the selection module 13 to determine an end of micro-break, for example by establishing as the first criterion to verify that the difference between the second measurement signal P2 and the second measurement signal Pl is less than a determined threshold.

  The second direct control module 12 can be provided for the case where abnormal variations in the position of the flap 3 are detected, which may for example be oscillations which appear when the flap 3 comes to strike against one or the other. stops 8, 9, 30 making it possible to limit an angular displacement of the flap 3. it

  To detect the appearance of oscillations of shutter 3 of actuator 1, the magnitude of the error between a position setpoint signal of shutter 3 and one or more position measurement signals can be used as a characteristic variable. of the shutter.

  In FIG. 3, a first graph, located in the upper part of the figure, shows an abscissa axis on which time is plotted and a y-axis on which plots of position setpoints and position measurement signals are plotted. part 3.

  A setpoint signal C is shown in thin lines and is substantially constant. A position measurement signal P is shown in solid lines. In a time interval for which the measurement signal P has significant oscillations, the measurement signal P has been represented by an envelope in dotted lines representing the amplitude of the oscillations.

  A second graph, located in the lower part of FIG. 3 and intended for simultaneous reading with the first graph, presents an abscissa axis on which is plotted the time and an ordinate axis on which is plotted the value of the integral I as a function of time the absolute value of the difference between the setpoint signal C and the measurement signal P of the first graph. The integral I is intended to be determined by the selection module 13, for the selection, if necessary, of the second direct control module 12. The integral I as a function of time is carried out over time intervals which do not not overlap, and having an identical duration called DI integration duration. The integration variable is reset to zero at the start of each new time interval.

  The criterion for detecting the oscillations is whether the integral I obtained during an integration time Dl exceeds a determined threshold S4, which indicates that the difference between the setpoint and the position of the flap 3 remains significant during the time and that there is no stabilization of the flap 3, for example after a shock on a stop 8, 9.

  In the first graph of FIG. 3, between an initial instant 5 Tii and an instant T12, the measurement signal P is substantially equal to the setpoint signal C. The integral I remains substantially zero. From time T12, oscillations of the shutter 3 appear. The integral I increases regularly until an instant T13 separated from the initial instant Tii by the integration duration Dl, and reaches a value 10 lower than the determined threshold S4. Consequently, a selection of a direct control mode for the position of the flap 3 is not carried out. The integration variable is reset to zero.

  From time T13, the oscillations of flap 3 continue. The integration variable I therefore increases up to an instant T14, separated from the instant T13 by a duration less than the integration duration D1, at which the integration variable I reaches the detection threshold S4. Oscillations are detected.

  From the instant T14, the selection module 13 causes the selection of the direct control module 12 which remains selected 20 until an instant T15 separated from the instant T14 by a determined duration of application D2. In this case, a control signal S for the position of the flap 3 of the actuator 1 is produced directly from the position setpoint C, using direct control, for example from predetermined tables which have been produced. specifically for such a situation. The command can be a degraded command mode with less precision.

  Preferably, between the instant T14 and an instant T16 separated from the instant T14 by a determined inhibition duration D3 greater than the determined application duration D2, the oscillation detection is no longer carried out. Indeed, after the selection of the direct control module 12, taking into account the fact that the position of the flap 3 has been controlled without taking account of signals for measuring the position of the flap 3, it may be that it there is an error between the position of shutter 3 and a setpoint signal C. During direct control, or after a return to regulated control mode, the detection of oscillations based on the integration of the error could cause a passage premature in direct control mode before resuming regulation could eliminate the position error. The duration of inhibition D3 is determined to allow stabilization of the shutter 3, and a correction of an error at the end of the direct control period.

  In practice, provision may be made for the detection to continue to operate, and for example the integration to continue to be carried out, however, the results will not be taken into account for modifying a selection of a control module.

  In certain cases, as in particular the case of large variations in setpoint C brought together over time, the absolute value of the difference between the setpoint C and a position measurement signal P of the shutter 3 may be large, due to a reaction time of the regulated control module 10, while disturbances of the operation of the actuator are not effective. To avoid in this case going into direct control mode, provision may be made for the position measurement signals of the shutter 3, used for detecting the oscillations, to be filtered beforehand in order to avoid too rapid determination of a oscillation of shutter 3.

  However, the position measurement signals Pi, P2 of the shutter 3 are preferably used directly for the production of a control signal in the regulated control module 10.

  Of course, in the case of modules with sampling of the 30 signals, provision may be made for a duration corresponding to a number of sampling steps, and for integration for a determined duration corresponding to the addition of successive values of a variable during a determined number of steps.

  In the embodiment described, provision has been made for the use 5 of two separate direct control modules, a first direct control module 11 in the event of micro-cuts observed on a sensor signal, and a direct control module 12 in cases of oscillation. Of course, a single direct control module could be provided.

  Thanks to the invention, a method for controlling and controlling a flow actuator in a fluid flow pipe is obtained, making it possible to improve the position control of a movable element of the actuator by detecting disturbances in the actuator's operation and by implementing actuations in direct control mode, allowing actuator control while waiting for the actuator to return to normal operation. The method according to the invention makes it possible, in particular, to detect in certain cases an end of disturbance of the operation of the actuator.

Claims (12)

  1. Method for controlling and controlling an actuator (1) for regulating flow in a circulation pipe (2) of a fluid, in which, in a controlled control mode, a control signal 5 is produced the position of a movable element (3) of the actuator as a function of a setpoint signal (C)) and at least one measurement signal (Pi, P2, P) of the position of the movable element , characterized in that the operation of the actuator (1) is controlled from at least one position measurement signal (Pi, P2, P) of the movable element, and if disturbances of the operation of the actuator (1) are detected, it switches to a direct control mode in which control signals are generated directly from a setpoint signal (C).   2. Method according to claim 1, characterized in that the position of the movable element (3) is measured using two position sensors, and the operation of the actuator is checked by comparing the signals of measurement (Pi, P2) of the two position sensors 3. Method according to claim 2, characterized in that it switches to direct control mode when the difference in difference A (P2-P1) determined as the difference between on the one hand the difference at a given time between the measurement signals of the two sensors and on the other hand the difference at a previous instant between the measurement signals of the two sensors is greater than a predetermined threshold.   4. Method according to claim 3, characterized in that it switches to direct control mode when the difference in difference A (P2-Pl) is greater than a determined threshold (Si) during a determined time interval.   5. Method according to any one of claims 3 or 4, characterized in that it switches again to regulated control mode if the difference in difference A (P2-Pl) is less than a determined threshold. 6. Method according to any one of the preceding claims, characterized in that it switches again to regulated control mode if the absolute value of the difference between the measurement signals (Pl, P2) of the two sensors is less than a determined threshold. 7. Method according to any one of the preceding claims, characterized in that when returning from a direct control mode to a regulated control mode, a constant control instruction is maintained for a determined period. 8. Method according to any one of the preceding claims, characterized in that it switches to direct control mode if the absolute value of the difference between the setpoint signal (C) and at least one measurement signal (P) the position of the movable element is greater than a determined threshold.   9. Method according to claim 9, characterized in that one integrates, for a determined period, the absolute value of the difference between the setpoint signal (C) and at least one measurement signal (P) of the position of the movable element (3) detected, and it switches to direct control mode if said integral (I) exceeds 25 in the determined time interval a determined threshold.   10. Method according to any one of claims 8 or 9, characterized in that it switches again to regulated control mode after a determined period of time (D2).   11. Method according to any one of claims 8 to 10, characterized in that when returning from a direct control mode to a regulated control mode, a detection of disturbances is inhibited for a determined period (D3) .   12. Device for controlling and controlling an actuator (1) for regulating the flow in a circulation pipe (2) for a fluid, in particular a butterfly for controlling the air flow admitted into an internal combustion engine , the actuator comprising at least one movable element (3) and a position sensor of the movable element, the device comprising a regulated control module (10) of the position of the movable element (3) as a function of a setpoint signal 10 (C) and at least one measurement signal (Pi, P2, P) of the position of the movable element (3), characterized in that it comprises a selection module (13 ) capable of controlling the operation of the actuator from at least one measurement signal (Pi, P2, P) of the position of the movable element (3), and capable of selecting a direct control module ( 11, 12) provided for producing control signals directly from a setpoint signal (C), if disturbances in the operation of the actuator (1) are detected.