Classifications

• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B19/00—Programme-control systems
  • G05B19/02—Programme-control systems electric
  • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
  • G05B19/19—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/41—Servomotor, servo controller till figures
  • G05B2219/41156—Injection of vibration anti-stick, against static friction, dither, stiction
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/41—Servomotor, servo controller till figures
  • G05B2219/41206—Lookup table, memory with certain relationships
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/42—Servomotor, servo controller kind till VSS
  • G05B2219/42235—Adaptive pulsing, augment time duration until movement detected

Definitions

• PWM pulse width modulation
• the PWM signal is converted into a current via the actuator using the first switch. Im closed, like Even when the first switch is open, the current flowing through the actuator is measured by the current measuring circuit. On this basis, the comparison required for the regulation of this current is carried out with the specified target value.
• a problem with the known control system is that the electromagnetic actuator usually has hysteresis. This leads, for example, to the use of the actuator in a transmission control
• the object of the invention is to provide a method for regulating the current through an electromagnetic actuator, which enables a higher accuracy of the regulation.
• This object is achieved according to the invention in a method of the type mentioned at the outset by changing the duration of an on and off cycle of the PWM signal and by providing the PWM signal with a so-called Dither function in the form of a low-frequency oscillation is superimposed.
• the change in the duration of a switch-on and switch-off cycle represents a change in the so-called chopper frequency of the PWM signal.
• Such a change in the chopper frequency makes it possible to reduce a so-called seat bounce of the electromagnetic actuator. It is also possible to reduce the hysteresis of the actuator, in particular in the medium current range, by reducing the chopper frequency.
• the chopper frequency can be selected depending on the temperature, so that the friction hysteresis of the actuator is reduced by lowering the chopper frequency. Overall, the regulation of the current by the actuator according to the invention can be significantly improved by influencing the duration of the on and off cycle of the PWM signal.
• the dither function further improves this regulation.
• the movable iron core of the actuator is prevented from changing into a state of static friction with the aid of the low-frequency oscillation of the PWM signal. It J-ann the iron core through the dither function continuously in one State of the sliding friction maintained and thus a minimal * hesteresis of the actuator can be achieved.
• the time period during which the dither value hmzuacl ⁇ iert the pulses of the PWM signal is preferably equal to the time period during which the dither value is subtracted from the pulses.
• the two time periods result in an overall time period that is a multiple of the time period of an on and off cycle of the PWM signal.
• the current measured by the current measuring circuit and flowing through the actuator is freed from a correction of the dither function. It is particularly advantageous if two current values are measured at the time interval of the time period during which the dither value is added to the pulses of the PWM signal or is subtracted, and that an average of these two measured current values is formed.
• the diagnosis determines the current through the actuator from the measured switch-on and switch-off times of the first switch, and the diagnosis determines this current with the current measured by the current measuring circuit and / or with the target value compared.
• the invention can also be implemented in the form of a computer program or in the form of a control device.
• the computer program can then be stored on an electronic storage medium.
• the control device can in particular contain those components of the invention that are implemented in software. Furthermore, the control device can have all those components that are required for coupling the software with the actuator and the associated hardware components.
• FIG. 1 shows a schematic block diagram of an exemplary embodiment of a system according to the invention for regulating the current through an electromagnetic actuator
• FIG. 2 shows a schematic block diagram of an exemplary embodiment of a control system for the system of FIGS. 1 and 2
• FIG. 3 shows a schematic time diagram of the control signal for the current through the electromagnetic actuator.
• the actuator 10 may be, for example, a coil with an iron core slidably arranged therein.
• the actuator 10 can be used, for example, in a transmission control of a motor vehicle or as an injection valve of an internal combustion engine or the like.
• the actuator 10 is connected to a supply voltage UV via a first switch 11 and to ground via a second switch 12.
• a current measuring circuit 13 is interposed between the actuator 10 and the second switch 12 and a monitoring 14 is connected.
• a free-wheeling diode 15 is connected in parallel with the actuator 10 and the current measuring circuit 13.
• a diagnostic circuit 16 is connected to the connection point of the actuator 10 and the first switch 11.
• the connection point of the current measuring circuit 13 and the monitoring 14 is connected to the supply voltage UV via a resistor 17.
• a control 20 is supplied with the supply voltage UV, with a signal representing the ambient temperature TU and with a signal characterizing a setpoint SW.
• a signal generated by the current measuring circuit 13 is processed by a correction 21 in order to then be passed on to the control 20.
• the controller 20 controls the first switch 11 on the one hand via a pulse generation 22 and on the other hand directly controls the second switch 12.
• a diagnosis 23 is acted upon by signals which are generated by the diagnosis circuit 16, the current measurement circuit 13 and the monitoring 14.
• the setpoint value SW is also present at diagnosis 23.
• the diagnosis 23 can act on the control 20.
• Figure 1 only a single actuator IC is shown. The system shown is suitable for regulating the current through this actuator 10. However, it is also possible for a plurality of actuators 10 to be present. In this case, those components which are arranged between the two dashed lines 25 in FIG. 1 are present in a corresponding plurality. In this case, therefore, there are not only a plurality of actuators 10, but also a plurality of respectively associated first switches 11, current measuring circuits 13, free-wheeling diodes 15 and diagnostic circuits 16.
• FIG. 1 shows those connections which are present more than once in this case as thicker lines.
• These connections can be, for example, bus connections in which each control valve 10 is assigned an individual line of the bus connection.
• the components shown between the two lines 25 are designed as hardware components.
• the components shown to the left of lines 25 in FIG. 1 are preferably implemented as software and provided for execution by a microprocessor or the like.
• a computer program is available, the program instructions of which are suitable for being executed on the microprocessor.
• the computer program is preferably stored on a flash memory, which is housed together with the microprocessor in a control device. Interfaces, analog / digital converters and the like, which are not shown in FIG. 1, may be present between the hardware components and the microprocessor or the control device.
• the control 20 of FIG. 1 is shown in more detail in FIG.
• the controller 20 has a pilot control 31, an I component 32 and a P component 33.
• the pilot control 31 is acted upon by the supply voltage UV, the ambient temperature TU and the setpoint SW. Depending on this, the
• Precontrol 31 a signal that is fed to an acknowledgment point 34.
• the feedforward control 31 has the task of keeping the deviation to be compensated for by the I component 32 and the P component 33 as small as possible.
• An actual value IW is subtracted from the target value SW at a subtraction point 35.
• the actual value IW corresponds to the signal that is generated by the correction 21 in FIG. 1.
• the difference determined by the suction part 35 acts on the I part 32 and the P part 33.
• the P part 33 generates a signal which is fed to the addition point 34.
• the generation of the I component 32 can be interrupted with the aid of two switches 36.
• the two switches 36 are controlled by a block 37, which in turn is acted upon by the setpoint SW.
• block 37 recognizes whether the
• Setpoint SW executes a jump that exceeds a predetermined maximum jump. If this is the case, block 37 opens the two switches 36 and interrupts the generation of the I component 32. The jump in the setpoint value SW v / is then corrected solely by the P component 33.
• the duration of the interruption of the I component 33 can be fixed or can be selected to be variable, for example depending on the jump height of the setpoint SW.
• the sum S generated by the addition unit 34 corresponds to that signal which is generated by the control 20 and which is supplied to the pulse generation 22.
• the system for leveling the current through the actuator (s) 10 shown in FIG. 1 functions as follows:
• the current through the actuator 10 is set using the first switch 11.
• the second switch 12 is closed in normal operation.
• Such a PWM signal is plotted as an example in FIG. 3 over time t.
• the PWM signal only distinguishes between an on state (“1”) in which the first switch 11 is closed and an off state (“0”) in which the first switch 11 is open.
• an on state (“1”) in which the first switch 11 is closed
• an off state (“0”) in which the first switch 11 is open.
• a current flows from the voltage supply UV via the first switch 11, the actuator 10, and the current measurement circuit 13 and the closed second switch 12 to ground.
• the first switch 11 is open, no such current flows.
• the current flowing through the actuator 10 can thus be influenced by varying the on and off times of the PWM signal.
• the PWM signal is generated by the pulse generation 22 as a function of the output signal from the controller 20.
• the pulse generator 22 converts the output signal of the control 20 m into a PWM signal, the ratio of the on and off times corresponding to the size of the output signal.
• the time period TC of an on and off cycle of the PWM signal corresponds to the so-called chopper frequency of the PWM signal.
• the regulation 20 and / or the pulse generation 22 can variably change this time period TC. If a plurality of actuators 10 are present, their time periods TC can be changed independently and variably.
• the individual actuators 10 are driven with a phase shift.
• the Time periods TC can influence this phase relationship in such a way that as few switching edges as possible coincide.
• Chopper frequency can also be used to achieve a reduction in the so-called seat bounce of actuator 10 by a smaller stroke amplitude of the displaceable iron core at a higher chopper frequency.
• the hysteresis of the actuator 10 can be reduced by a lower chopper frequency, particularly in a medium current range.
• the chopper frequency can be set as a function of temperature such that the chopper frequency is reduced at lower temperatures, so that a friction hysteresis of the actuator 10 which is present at lower temperatures is reduced.
• the control 20 and / or the pulse generation 22 can carry out a so-called dither function, which is a low-frequency vibration superimposition for the current through the actuator 10.
• a predeterminable dither value DW is added or subtracted to the PWM signal determined per se.
• This dither function can be carried out independently and variably for a plurality of actuators 10. For an individual actuator 10, this is shown in FIG. 3 in that the individual pulses of the PWM signal are first extended by the dither value DW and then shortened. The time period T1 in which the individual pulses are extended is equal to the time period T2 in which the pulses are shortened.
• the total time duration TD of the dither function resulting from the two aforementioned time periods T1, T2 additively is a multiple of the time period TC of the chopper frequency.
• the time period TD is ten times the time period TC.
• the movable iron core of the actuated actuator 10 changes into the state of static friction.
• the iron core can thus be kept continuously in a state of sliding friction by the dither function and thus a minimum hysteresis of the actuator 10 can be achieved.
• the regulation 20 is initiated at predetermined time intervals and according to the number of available
• Actuators 10 executed. It will be available for all Actuators 10 corresponding output signals from the controller 20 to the pulse generator 22 v / eit, which then continuously generates the associated PWM signals for the various actuators 10, with which the respective first actuators 10 associated with the various actuators 10 are controlled.
• the current flowing in this way via the various actuators 10 is measured by the respectively associated current measuring circuit 13.
• the current measuring circuit can preferably be a so-called shunt resistor.
• the measured current value is passed on to the correction 21, where the dither function introduced by the control 20 or the pulse generation 22 is calculated out again. This ensures that the
• the dither function can be compensated in the correction 21, for example, by forming the mean value from two current values measured at the time interval of the time period T1. Due to the relationship between the time period TD of the dither function and the time period TC of the chopper frequency, the dither function and in particular the dither value DW are no longer contained in the above-mentioned mean value. As has already been explained, correction 21 passes the measured current value, which has been freed of the dither function, to control 20 as actual value IW.
• the measured current value is also passed from the current measurement line 13 to the diagnosis 23 v / e. There, the measured current value is compared with the setpoint SW. In the event of a deviation that exceeds a predeterminable maximum value, the diagnosis 23 can either intervene in a corrective manner via the control 20 or switch off the current by the relevant actuator 10 or even for all existing actuators 10.
• the potential present between the actuator (s) 10 and the second switch 12 is monitored by the monitor 14 and passed on to the diagnosis 23. If this potential is faulty, in particular if there is a short circuit to the supply voltage UV, the second switch 12 is immediately opened by the diagnosis 23 via the control 20, so that no more current can flow through the actuator (s) 10.
• the potential present between the actuator (s) 10 and the first switch 11 is monitored by the diagnostic circuit 16 and passed on to the diagnosis 23. If this potential is incorrect, lies 13
• the first switch 11 is immediately opened by the diagnosis 23 via the control 20 so that no current can flow through the actuator 10.
• diagnosis circuit 16 recognizes those times at which the first switch (s) 11 are opened and closed. From these measured times, the respective current value can be determined by the diagnosis 23
• Actuator 10 flows. This determined current value is compared with the current value measured by the current measuring circuit 13 and / or with the target value SW. If a deviation is ascertained by the diagnosis 23 that is larger than a predetermined maximum value, then the
• the current flowing through the actuator 10 is monitored multiple times and thus redundantly. This also applies to a plurality of existing actuators 10.
• the second switch 12 Before the first operation of the system shown in FIG. 1 for regulating the current through the actuator (s) 10, that is In particular, during an initialization of the system, the second switch 12 is still open, so that no current flows through the actuator (s) 10. The potential between the actuator (s) 10 and the second switch 12 can thus be determined mcnt per se.
• resistor 17 is only present once and has a rather large resistance value. Due to the resistance 17, the potential between the /
• Actuator (s) 10 and the second switch 12 are determined by the monitoring 14 and thus a short circuit to the supply voltage UV or to earth are determined.
• Chopper frequency and the dither function can be used in the same way as described in FIG. 1

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• Engineering & Computer Science (AREA)
• Human Computer Interaction (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Automation & Control Theory (AREA)
• Magnetically Actuated Valves (AREA)
• Control Of Linear Motors (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
• Dc-Dc Converters (AREA)

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Citations (2)

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• 2002
  • 2002-09-14 DE DE10242790A patent/DE10242790A1/de not_active Ceased
• 2003
  • 2003-06-10 EP EP03740069A patent/EP1540431B1/de not_active Expired - Lifetime
  • 2003-06-10 JP JP2004536814A patent/JP4878118B2/ja not_active Expired - Fee Related
  • 2003-06-10 US US10/527,291 patent/US7206180B2/en not_active Expired - Fee Related
  • 2003-06-10 DE DE50313270T patent/DE50313270D1/de not_active Expired - Lifetime
  • 2003-06-10 CN CNB038017687A patent/CN100449438C/zh not_active Expired - Fee Related
  • 2003-06-10 WO PCT/DE2003/001904 patent/WO2004027529A1/de not_active Ceased

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