FR2703796A1 - Method and device for positioning an adjustment installation - Google Patents

Abstract

a) Method and device for positioning an adjustment installation. b) Method and device, in particular for adjusting the throttle flap of a vehicle by an analog position regulator, the regulator setpoint being formed by a conversion means, preferably a low pass filter from a pulse signal created by the calculation element as a function of the operating parameters.

Description

"Method and device for positioning an installation

adjustment".

  The present invention relates to a method of positioning an electrically controlled adjustment system, with a setting means which receives at least one signal representing the desired position,

  at least one calculation element that creates the

  representing the desired position from the paragraphs

  The invention also relates to a device for positioning an electrically controlled adjustment installation comprising at least one calculation element to create a signal representing the desired position for

  setting system, adjusting means which

  set the desired position by operating the adjustment system.

  Such a method or arrangement is already known.

  according to DE-OS 35 10 176 (US Pat.

  4 622 936) This document describes for example a component

  throttling of a motor vehicle, electrically controlled

  The positioning of the throttle flap is done by an electric motor and a power stage using a position controller, depending on the difference between a real position value detected by an element.

  measuring device and a setpoint value, predetermined

  The setpoint value of the position is formed

  operating quantities such as the position of a driver-operated control element, in

  a calculation element to be provided as a level of

  Analog output or position controller The positioning accuracy of the control system depends on the

  known solution, the resolution of a digital converter

  / Analog transforming the numerical representation of the set value in the calculator into a level

  In addition to the resolution, this converter

  mite also the speed of variation of the set value. The present invention thus aims to create

  means allowing a precise position of an installation

  by improving the known procedure, pre-

  without significantly increasing the implementation

switching means.

  For this purpose, the calculation element provides the

  their digital setpoint of a pulsed signal.

  with at least one variable parameter which is converted into an analog setpoint set by the analog controller to position the control system. Such a process is known according to the previously unpublished application DE-P 42 03 191 in the context of the

  regulating the current of a phase of a stepping motor.

  Advantages of the invention The invention relates to a method characterized in that the signal representing the desired position is a

  pulse signal with at least one calculation element.

  The method according to the invention makes it possible

  an adjustment installation in an exact

  requesting that a circuit implementation, reduced.

  It is furthermore advantageous to be able to maintain a numerical predetermination of the set value in a calculation element in order to use the advantages of a calculation element in connection with the calculation of the setpoint value.

  Advantageously, the convert is removed.

Digital / Analogue.

  The process according to the invention is particularly

  important because it allows for greater resolution

  than allowed by a converter

usual digital / analog.

  The use of low pass filter the second or

  fourth order can be used to reduce satisfactorily

  the residual ripple of the setpoint

  analogue, obtained from the pulse signal and

  holding at least one variable parameter.

  Advantageously, there is a signal width

  modulated pulse for which the predefined calculating element

  ends the length of the impulse, that is, the ratio

  according to the calculated setpoint.

  The program steps related to this operation in the

  Calculations are particularly simple.

  The simple linear relationship between the ratio of

  modulated pulse width signal work and the

  their deposit is particularly advantageous.

  assigned according to the invention allows without implementing

  important means, a precision of 12 bits.

  The application of the process according to the invention

  connection with an analog position controller to re-

  set a power adjustment element as a shutter

  throttle or a control bar of a combustion engine

  internal bustion is a particularly useful application

tageuse.

  In addition to the choice of a pulse width signal

  modulated variable ratio variable work, according to other embodiments, one can have a pulse signal

  of variable frequency and fixed pulse width.

  According to other advantageous features of the invention: the adjustment means also comprise an analog position regulator receiving the analog signal for the desired position as well as a real value signal representing the position of the adjustment installation, and which determines a measure of the difference between the set value and the actual value; the output signal of the analog position controller is transformed into a modulated pulse width signal for controlling

  the electrically operated adjustment system; the in-

  electrically controlled adjustment device and the throttle flap of a motor vehicle which is actuated via an electric motor, a

  direct current or rotary actuator.

  The present invention will be described hereinafter

  in more detail using alternative embodiments of

  shown in the drawings in which: FIG. 1 shows a block diagram

  implementation of the method according to the invention.

  Figure 2 shows the timing diagram of a signal

  setpoint value predetermined by a calibration element

  ass. Figure 3 shows an example embodiment

  conversion means to convert the value of

  impulse generator into an analog setpoint.

Description of the embodiment

  In FIG. 1, reference numeral 10 designates a unit

  control unit comprising at least one calculation element.

  The control unit 10 receives the input lines 12 to 14 from the measurement system 16 to 18 to enter quantities or operating parameters of the unit

  motor and / or vehicle An exit line 20 from the

  order 10, if necessary, through the

  of adapter means 22, to conversion means

  24 Their output signal 26 is fed to the regulator

  position logic 28 which also receives the line of

  The output line 32 of the analog position controller 28 leads to another connected conversion means 34.

  by its output line 36 to a power stage 38.

  The power stage 38 controls by its output lines and 41 a motor 42, preferably a DC motor. This motor is connected by a mechanical link 44 to a power adjusting element 46, in particular a shutter.

  throttling of an internal combustion engine not

  The engine 42, the link 44 or the throttle flap

  46 are also connected by another active link to a measuring device 50 to enter the setting element position 46 or the link 44 or the motor 42. The output line 30 of the measurement system 50

  led to the position controller 28 which includes the

  setting which is to be set and which according to the

  tion is a power adjusting element 46, a link

  44, a motor 42 and / or a measuring installation 50.

  The device according to FIG.

  O setting up the installation at a predetermined position.

  This is defined according to the operating parameters

  it receives, for example on the basis of

  characteristics, characteristic curves, tables

  or equations The characteristic quantities of

  particularly represent the position of an operating element to be operated by the driver in the case of

  electronic acceleration pedal system, the temperature

  engine speed, the engine rotation speed, the

  battery voltage, the motor load, etc. for a

  idle speed control, vehicle speed and

  maneuvering machines of an operating lever in the case of

  displacement speed controller, rotational speed

  wheels in the case of the

  skating, etc. The method according to the invention can be used

  advantageously in connection with all these applications.

  A preferred application is an electronic control

  engine power in the case of an accelerator pedal, electric, idle speed control, speed control and slip regulation by positioning the control element at

  using an analog position controller.

  The calculated reference value is transformed by the computer 10 into a rectangular signal with a preferably modulated pulse width. The computer determines the working ratio of the signal in that it determines, for example, the length of the pulses or the instant of the end of the impulse within a predetermined period of

pulse shape signal.

  Figure 2 sketches such a signal; in abscis

  it is represented the time and on the ordinate, the level of the PWM signal emitted by the control unit 10 in the line

  The period To is given as fixed whereas the

  pulse width t or work report t / To is defined

  by the calculation element according to the function parameters

  In other words, the desired position of the

  The adjustment ratio is provided by the control unit digitally by a modulated pulse width signal. The working ratio t / To of this signal is preferably linked by a linear relationship with the setpoint value U1 of the controller. analog position, value

  formed by conversion (in element 24) from the

  general PWM; this report is thus essentially in relation

  linear with the position of the installation of re-

  SETTING; in the preferred embodiment, the

  lation is done with the position of a throttle flap

  for a range of angle between about 0 and 900.

  According to another advantageous embodiment, the

  setpoint signal, digital generated by the element

  The calculation method may be a pulse duration signal.

  period To variable according to the operating parameters

  and a fixed pulse width t at fixed period To and

  variable duration (TO t), a sawtooth signal,

  fixed period and variable slope (by predetermining the rise time) or variable period or a triangular signal. The pulse width modulated signal formed by the computer is transmitted, if necessary, by a level matching element 22 which, as the case may be, adapts the level and / or a level limitation to adapt the voltage level of the output of the control unit to the accuracy of the application That by that

  the analog position regulator 28, which will follow later

  secondly, ensures the positioning of the installation of

  next setting of absolute signal values

  This increases the position value with the output signal level. In addition, it may be advantageous to maintain a maximum level that can be handled by the controller.

position.

  After the level adaptation, we provide the

  pulse width modulated signal to the conversion means

  24 which transforms this signal into a voltage signal,

  These conversion means 24 comprise according to

  an example of a preferred embodiment, filters

  tegrators with discrete components whose construction and dimensioning are chosen according to the application case

  taking into account the dynamics and the ripple

  dual signal Ul It turned out that a low pass filter

  was a particularly suitable means of conversion.

  Depending on the application, active or passive low-pass filters of different orders can be used. According to a preferred embodiment, it has been found that a fourth-order low-pass filter such as that represented in FIG.

  for example in Figure 3, gives good results

  the residual ripple and dynamics when

  difies the modulated pulse width signal.

  Other filters and integrators can be used

  in other exemplary embodiments with equally advantageous effects. UT analog voltage signal is provided

  line 26 as the position reference value in the

  analog position giver 28 realized in a manner

  naked, for example with operational amplifiers and

  presenting according to the application a proportional behavior

  tional-integral and / or differential The process according to

  The invention also has advantages in the context of other types of regulators, such as

  two or three point regulation, etc. In the regular

  analog position transmitter 28, from the setpoint U 1 and the position of the setting system U 2 (actual value) entered by the measuring unit 50,

  form a measure of difference: the value of

  gne / actual value U 3 This signal is provided as a signal of

  output-from the regulator to the conversion means 34

  sion U 3 is again transformed into a commu-

  modulated pulse width command to be provided by

  line 36 at the power stage 38 The means of con-

  versions 34 form the pulse width signal modulated for example in a known manner using a comparison of the analog voltage signal U 3 and a voltage value which changes over time with a fixed period, following a

  sawtooth or triangle pattern.

  In a preferred exemplary embodiment, the modulated pulse width signal 36 controls a full bridge power stage 38 for clockically controlling a DC motor. The DC motor 42 moves toward the desired position until it reaches the desired position. the difference between the actual value and the nominal value is practically zero, that is to say

  until you are in the desired position.

  The measuring element 50 which detects the position of the adjustment installation can be in the simplest case, a potentiometer; in other applications he

  may be a non-contact position sensor.

  In addition to the example of preferential application

  position regulation, a balanced throttle

  an internal combustion engine, the process according to the

  may also apply in connection with the

  position control with stepping motors, ac-

  or in the case of air-conditioning installations

  control rods or pump levers

  The method according to the invention for pre-

  the numerical value of the setpoint by a pulse signal

  by taking into account at least one variable parameter in connection with regulators having other designs

  on motor vehicles, may apply to

  rotational speed latters, pressure regulators

  3 shows a preferred embodiment of the conversion means 24 which is a fourth-order active, low-pass filter. The input 100 of the conversion means 24 receives the PWM signal at modulated pulse width from the control unit 10 This signal has been optionally adapted in level or limited and is transmitted by a resistor R1 to a point of combination 102, a resistor R 3, a point of combination 104,

  to arrive at the positive input of an operational amplifier

  A capacitor C1 connects the point of combination

  its 104 to the ground The output of the operational amplifier 106 is connected to a combination point 108 to

  from which a capacitor C 2 is connected to the point of contact

  binaison 102, while a line 110 returns to the ne-

  A third resistor R 3 connects the combination point 108 by a combination point 112, a fourth resistor R 4, a combination point 114, to the positive input of a second amplifier A capacitor C 3 connects the combination point 114 to the ground. The output of the operational amplifier 116 is connected to a point of contact.

  combination 118 from which a capacitor C 4 is

  linked to the combination point 112; a line 120 connects back to this combination point to the negative input of

  the operational amplifier 116 and a fifth resistor

  R 5 is connected to ground The combination point 118

  constitutes the output U 3 of the conversion means 24.

  The described circuit corresponds to a pass filter

  fourth-order low It has been shown that the ripple

  dual signal U, for a PWM signal level of approximately volts and appropriate choice and dimen

  circuit elements, is about 100 microvolts.

  In comparison, a construction low pass filter corresponds to

  second order (R 3, R 4, C 3, C 4, R 5).

  Operator 116) present for the same level of

  PWM signal, a residual ripple of about 20 milli-

  volt, however, in a state of stable oscillation.

  plications requiring high resolution and low residual ripple, a fourth-order low-pass filter is preferably used according to the realization of conversion means 24; in other embodiments, a filter of

second order may suffice.

he

Claims (9)

R E V E N D I C A T IO N S   1) A method of positioning an electrically controlled adjustment system, with a setting means which receives at least one signal representing the desired position,   at least one calculation element that creates the   representing the desired position from the paragraphs   operating meters, characterized in that, the signal representing the desired position   is a pulse signal with at least one parameter   created by at least one calculation element.   2) Process according to claim 1, characterized   in that the variable parameter of the pulse signal represents the width of the pulse for a fixed period, the duration of the period for a fixed pulse width or the working relationship.   3) Method according to one of the preceding claims   characterized by conversion means which form an analog voltage signal from the pulse signal.   4) Method according to one of the preceding claims   cedentes, characterized in that the conversion means are filters.   5) Method according to one of the preceding claims   cedentes, characterized in that the conversion means   are low-pass filters, preferably the fourth or- dre.   6) Method according to one of the preceding claims   cedes, characterized in that at least one calibration element   ass creates the pulse signal on the basis of the operating parameters, the variable parameter being defined according to the parameters, the pulse signal being   transformed by the conversion means into an analog signal   that represents the desired position for the installation adjustment.   7) Method according to one of the preceding claims   cedeentes, characterized in that the adjusting means com-   also take an analog position controller receiving the analog signal for the desired position   as well as a real value signal representing the posi-   adjustment installation, and which determines a   sure of the difference in the set point and the actual value.   8) A method according to one of the preceding claims   cedes, characterized in that the output signal of the   Analog Position Gauge is transformed into a modulated pulse width signal to control the installation   electrically operated adjustment device.   9) Method according to one of the preceding claims   cedeentes, characterized in that the adjustment installation   electrical control and the throttle flap of a vehicle   automobile which is operated by means of an electric motor, a DC motor or a motor rotary actuator.   ) Device for positioning a plant   a power control setting comprising: at least one calculating element for creating a   signal representing the desired position for the installation   an adjustment means which regulates the desired position by operating the adjusting device, characterized in that the signal generated by the calculating element is a pulse signal with at least one variable parameter, the magnitude of this variable parameter being a measure of the desired position.