Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D11/00—Arrangements for, or adaptations to, non-automatic engine control initiation means, e.g. operator initiated
  • F02D11/06—Arrangements for, or adaptations to, non-automatic engine control initiation means, e.g. operator initiated characterised by non-mechanical control linkages, e.g. fluid control linkages or by control linkages with power drive or assistance
  • F02D11/10—Arrangements for, or adaptations to, non-automatic engine control initiation means, e.g. operator initiated characterised by non-mechanical control linkages, e.g. fluid control linkages or by control linkages with power drive or assistance of the electric type
  • F02D11/105—Arrangements for, or adaptations to, non-automatic engine control initiation means, e.g. operator initiated characterised by non-mechanical control linkages, e.g. fluid control linkages or by control linkages with power drive or assistance of the electric type characterised by the function converting demand to actuation, e.g. a map indicating relations between an accelerator pedal position and throttle valve opening or target engine torque
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
  • F02D2041/1413—Controller structures or design
  • F02D2041/1431—Controller structures or design the system including an input-output delay
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
  • F02D2041/1413—Controller structures or design
  • F02D2041/1432—Controller structures or design the system including a filter, e.g. a low pass or high pass filter
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/0002—Controlling intake air
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D41/0047—Controlling exhaust gas recirculation [EGR]
  • F02D41/0077—Control of the EGR valve or actuator, e.g. duty cycle, closed loop control of position

Definitions

• the invention relates to actuator position servo systems equipping a motor vehicle. More particularly, the invention relates to the compensation of pure delays present in these position control systems.
• actuators include actuators present in the air loop of a motor vehicle such as a valve / exhaust gas recirculation valve, commonly referred to as the EGR valve, or an air intake butterfly of a turbocharger.
• FIG. 1 illustrates, by way of example, the overall architecture of a system 100 for controlling the position of an actuator 1, implemented in the computer of a motor vehicle.
• This architecture includes a supervisor 2 in charge of ordering (dashed arrows) the following tasks:
• This control task is performed by a position controller 4, implementing a control law of the actuator 1;
• FIG. 2a illustrates the servo-positioning performance of an actuator 1 of the air loop of a motor vehicle for a perfect system, that is to say having no pure delay. In this figure are illustrated two curves:
• the curve 201 in thick dashed lines shows in ordinate, in percentage, a position setpoint for an actuator 1, as a function of a time in seconds represented on the abscissa;
• the curve 202 in fine solid lines illustrates in the ordinate, at the same percentage scale, the position of the actuator 1 as a function of the same time in seconds represented on the abscissa.
• this pure delay can be attributed to accumulations of different delays such as:
• the curve 203 in thick dashed lines illustrates in ordinate, in percentage, a position setpoint for the actuator 1, as a function of a time in seconds represented on the abscissa;
• the curve 204 in full-line shows in ordinate, at the same scale of percentage, the position of the actuator 1 according to the same time in seconds represented in abscissa.
• FIG. 2b shows a performance degradation compared with FIG. 2a, in particular the presence oscillations around the position set point.
• the absence of compensation for the pure delay causes the position controller 4 to significantly degrade the closed loop response time of the actuator 1, in order to maintain acceptable overshoot values of the position setpoint, typically less than 5%.
• a known solution in the general field of automatic is to add to a system 100 servo, such as that shown in Figure 1, a predictor 6 delay.
• the latter has the task of correcting the command developed by the position controller 4, in order to mitigate the impact of the pure delay on the quality of the servocontrol in the position of the actuator 1.
• the predictor 6 of delay takes as inputs, the inputs 102 and outputs 103 of the regulator 4, and develops a compensation 104 of the pure delay, it returns to the regulator 4 position.
• Various solutions are known for producing a delay predictor in a servo system.
• the document FR2749613 describes a system for regulating the richness of the air-fuel mixture in an internal combustion engine, this system comprising a control device produced in the form of a Smith predictor.
• the structure of the Smith predictor described in this document proves, however, particularly complex to implement, and remains expensive in terms of computational load induced.
• the implementation of such a solution involves a particularly complex adjustment of a set of parameters at the on-board computer in the vehicle, such a setting being expensive in time of realization.
• the predictors of existing delays are, in the state, not adapted to the position control for actuators equipping a motor vehicle.
• An object of the present invention is to overcome all the aforementioned drawbacks.
• a second object of the present invention is to provide a pure delay compensation device for an actuator position servo system fitted to a motor vehicle.
• a third object of the present invention is to minimize the complexity of implementation of a pure delay compensation device, for an actuator position servo system in a motor vehicle.
• a fourth object of the present invention is to optimally control the position of the actuators in a motor vehicle.
• a servo system of the position Y (s) of an actuator to a position setpoint R (s) in a motor vehicle having a function predetermined transfer G (s) associated with a pure delay e ⁇ ds , s being the Laplace variable, d representing the pure delay, this system being realized via:
• the position control U (s) being elaborated using a Proportional Derivative type regulator, formed by a Proportional action loop and a Derivative action loop, made respectively by a first and a second loop of feedback between the Y (s) position and subtractor inputs of a first adder, the controller performing a third feedback loop between the Y (s) position and a subtractor input of a second adder, the second adder having as summing input the position setpoint R (s); the position setpoint R (s) also being used as input of an amplifying loop whose output is connected to an summing input of the first adder;
• the output of the second adder being used as an input of an integral action loop whose output is connected to an summing input of the first adder, so that the first adder calculates at its output the position U (s) according to its inputs summators and subtractors;
• this system comprising a pure delay compensator in which: the position control U (s) is used as the first summing input of a third adder and as input of a pure delay block of transfer function e ⁇ ds , the output of this pure delay block being used as the subtractor input of the third adder, so that the third adder calculates its output from its summing input and its subtractor input;
• the input of a high-pass filter is connected to the output of the third adder
• the input of an amplifier is connected to the output of the high-pass filter
• the output of the amplifier corresponds to a delay compensation term P (s), this output being used as a subtracting input by the second adder.
• the high-pass filter and the amplifier are sized from a first-order system approximating the transfer function G (s) of the actuator, this system having a static gain k and a time constant ⁇ .
• the amplifier has for gain, the static gain k.
• the high-pass filter has the function of transfer.
• ⁇ 2 is a parameterizable time constant.
• the Proportional action loop is associated with a gain k £
• the actuator is an actuator of the air loop of a motor vehicle.
• a motor vehicle comprising the computer described above.
• FIG. 1 illustrates the overall architecture of a position servo-control system of an actuator implemented in a computer equipping a motor vehicle;
• FIGS. 2a and 2b illustrate the temporal variations of the position of an actuator, respectively for a perfect and real servo-control system, with respect to a position command;
• FIG. 3 illustrates a device for controlling the position of an actuator
• Figure 4 illustrates a position servo system of an actuator including a Smith predictor
• FIG. 5 illustrates a system for controlling the position of an actuator comprising a pure delay compensator according to one embodiment.
• FIG 3 a position control device 300 of an actuator 1, the device 300 having a pure delay d_.
• the actuator 1 is, for example, an actuator of the air loop of a motor vehicle, such as a valve / a valve of an exhaust gas recirculation system, or a throttle valve. admission of a turbocharger.
• the servo-control device 300 is here represented in the Laplace domain and can be implemented in a position controller 4, such as that illustrated in FIG.
• the position controller 4 is configured to implement a control law of the position of the actuator 1. To do this, the behavior of the actuator 1 in the control device 300 is modeled by a transfer function G (s) in the Laplace domain, where s is the Laplace variable.
• the transfer function G (s) can be obtained in different ways, for example communicated directly by a model provided by the manufacturer of the actuator 1, modeled via an appropriate simulation tool (eg Simulink®), or still obtained experimentally by applying to the actuator 1 a step-type input and observing its output response.
• an appropriate simulation tool eg Simulink®
• the pure delay d. associated with the actuator 1 is meanwhile represented by the term e ⁇ ds in the Laplace domain.
• the actuator 1 and its pure delay are modeled by a transfer function block 30 G (s) e ⁇ ds , receiving for input a position command U (s) destined for the actuator 1.
• the actual position of the actuator 1, following receipt of the position control U (s), corresponds to an ideal response of the actuator 1, to which is added a disturbance on its position.
• the ideal response of the actuator 1, following receipt of the position command U (s), corresponds to the application of the transfer function G (s) e ⁇ ds , whose response is obtained at the output of the block 30.
• the disturbance in position results, in turn, in particular aeraulic forces applying to the actuator 1, for example pressure variations during its movement.
• the disturbance on the position of the actuator 1 is represented in FIG. 3 by the function D (s) at the input of an adder 7, the other input of this adder 7 corresponding to the ideal response of the actuator 1 following the command U (s), that is to say here to the output response of the block 30 without disturbance.
• a real position Y (s) of the actuator 1 is observed in response to the command U (s).
• the summator 7 and the variable D (s) are represented here for purposes of theoretical understanding.
• the actuator 1 thus has the output of the transfer function block G (s) e ⁇ ds a position Y (s) in response to the command U (s), this position Y (s) being the position that it is desired to slave to a position setpoint value R (s).
• the position control U (s) is developed as an output of a first adder 31 having two subtracting inputs "-" and two summing inputs "+".
• the subtractor inputs of the first adder 31 are produced by a Regulator of the Proportional Derivative type, commonly referred to by the acronym "PD regulator".
• PD regulator is formed of a proportional action loop, performing a gain amplification operation kjD;
• the proportional action loop and the derivative action loop respectively provide a first and a second loop 32, 33 of feedback between the output of the block 30, that is to say the position Y (s), and a subtractor input "-" of the first adder 31.
• a third feedback loop 34 is also provided by the controller between the position Y (s) and a subtracting input "-" of a second adder 35.
• the second adder 35 further comprises, for summing input "+", the position setpoint value R (s), this value being determined by the motor vehicle computer, as a function, for example, of parameters measured in the loop. air.
• This position setpoint value R (s) corresponds to the setpoint value at which it is desired to control the position Y (s) of the actuator 1.
• the position reference value R (s) is also used as input of a gain amplifier loop kf_ whose output is connected to a summing input "+" of the first adder 31.
• the output of the second adder 35 serves as input to a loop 37 with integral action, performing an operation integration, symbolized by the block "I”, sometimes also symbolized by a block "1 / s", associated with a gain k [.
• the output of this integrally acting loop 37 is connected to a summing input "+" of the first adder 31.
• the first adder 31 determines the control in position U (s) to be applied to the actuator 1.
• the gains kf, k [, k £ and kd_ are static values currently determined with respect to the transfer function G (s), previously known, for example via the application of a pole placement method. These parameters are, by way of example, determined by simulation via a development tool of the motor vehicle computer and / or adjusted experimentally at the computer, for example as a function of the course of a series of tests intended to validate the computer. specifications of the vehicle. These gains are here preconfigured.
• the device 300 for controlling the position of an actuator Icomprets in particular: feedback loops 32, 33 on the position Y (s) of the actuator 1, performed by a regulator of Proportional Derivative type;
• PD-I acronym for "Proportional Derivative - Integral”
• PID Anacronym Integral Derivative
• Such a structure differs from common PID (Acronym Integral Derivative) controllers, in that only the integral term lies on the error of position e (s), while the proportional and derivative actions are indexed only on the position Y (s) of the actuator 1. This has the advantage of being able to decouple the performance of tracking setpoint and the performance of rejection of disturbances.
• a servocontrol structure is realized in motor vehicle computers for the position control of the actuators 1.
• the position control device 300 of FIG. 3 comprises here for transfer function:
• a delay compensator such as a Smith predictor 40 shown in Figure 4.
• the predictor 40 of Smith is realized in the following manner.
• the position control U (s) at the output of the first adder 31 is used as the summing input "+" of a third adder 41 and as input of a block 42 of pure transfer function delay e ⁇ ds , the output of this delay block being used as the subtracting input "-" of the third adder 41.
• the block 42 use of pure delay implies that the delay d. is known. This is in practice estimated by applying to the actuator 1 a step-type input and observing its output. It can be calibrated more finely when setting the position controller 4.
• the third adder 41 then calculates its output from its summing input "+” and its subtracting input "-”. This output is connected as input to a transfer function correcting block C (s) .G (s) whose output is used as a subtractor input "-" of the first adder 31.
• C (s) here denotes a function parameterizable transfer specific to the block 43 corrector.
• the presence of the Smith predictor 40 makes it possible to extract the pure delay e ⁇ ds from the feedback loop 34 between Y (s) and R (s), that is to say of the closed loop.
• the transfer function of this system is therefore equal to a closed-loop response H (s) of the actuator 1, shifted in time by a pure delay d_.
• the position Y (s) of the actuator 1 will therefore be followed by a tracking of the position setpoint R (s) close to FIG. 2a, with a simple offset temporal and no longer oscillations on the position Y (s) of the actuator 1.
• the pure delay d. has not disappeared, but becomes less detrimental to the position control of the actuator 1.
• the use of a predictor 40 Smith is therefore effective for the position control of the actuator 1.
• this predictor 40 requires a fine and complex adjustment of all the parameters of the transfer function H (s).
• the transfer function G (s) of the actuator 1 is then approximated by a first-order system:
• the variables k and ri are respectively a static gain and a time constant associated with the first order system, these values also being specific to the transfer function G (s) of the actuator 1.
• the variables k and he are easily deductible from the actuator 1. These variables are for example determined by simulation via an approximation of the transfer function G (s), or experimentally, by observing the response of the actuator 1 to a step applied at the input of it.
• T (s) k ⁇ 2S + 1 ⁇ ; we note that it is then enough to set the time constant ⁇ 2 to the value to approximate the product C (s) .G (s).
• the transfer function T (s) is k- the product of a gain integrator k1 (term, a high-pass filter of time constant ⁇ 2 having the function of transfer ⁇ and the static gain k of the actuator 1.
• control device 300 which is associated with a pure delay compensator 50 is implemented in the following manner.
• the position control U (s) at the output of the first adder 31 is used as the summing input "+" of a third adder 41 and as input of a block 42 of pure transfer function delay e ⁇ ds , the output of this delay block being used as the subtracting input "-" of the third adder 41.
• the third adder 41 then calculates its output from its summing input "+” and its subtracting input "-”. This output is connected as input to a high-pass filter 51.
• the output of the high-pass filter 51 is connected to a gain amplifier 52 k, where k. is the static gain k. (predetermined) of the actuator 1.
• the high-pass filter 51 and the amplifier 52 are therefore sized from the first-order system approximating the transfer function G (s) of the actuator 1.
• the output of the amplifier 52 then corresponds to a delay compensation term P (s). This output is used as the subtracting input "-" for the second adder 35.
• the variables kjD and k are preconfigured during the realization of the servo system.
• the static gain k and the time constant II are predetermined variables of a first-order system approximating the transfer function G (s) of the actuator 1.
• the compensator 50 of pure delay the only remaining magnitude to be calibrated is the variable r2 of the high-pass filter 51.
• This calibration is easily performed by calibrating ⁇ 2 to the value -.
• the realization of this compensator 50 of pure delay is therefore very fast, easy to implement, and does not imply complexity in terms of computing load.
• the calibration of actuator position servo systems are simplified, which allows to gain time during their development.
• the embodiments described above are applicable to any actuator 1 of the air loop of a motor vehicle, for example to a valve / valve for the recirculation of the exhaust gas, or to an air intake butterfly of a turbocharger.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Feedback Control In General (AREA)
• Control Of Position Or Direction (AREA)

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• 2015
  • 2015-08-24 FR FR1557874A patent/FR3040504B1/fr not_active Expired - Fee Related
• 2016
  • 2016-07-11 EP EP16744823.2A patent/EP3341604B1/de active Active
  • 2016-07-11 WO PCT/FR2016/051769 patent/WO2017032931A1/fr active Application Filing

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