CN100408405C - Electric power steering system - Google Patents
Electric power steering system Download PDFInfo
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- CN100408405C CN100408405C CNB2003101170815A CN200310117081A CN100408405C CN 100408405 C CN100408405 C CN 100408405C CN B2003101170815 A CNB2003101170815 A CN B2003101170815A CN 200310117081 A CN200310117081 A CN 200310117081A CN 100408405 C CN100408405 C CN 100408405C
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Abstract
The electric power steering device 10 is equipped with a determination part 60 to determine a state of going or returning. The determination part 60 to determine the state of going or returning determines the state of the steering wheel as a returning state, and thereafter the returning state is continued until an absolute value of a rotation speed of the motor to be detected by a detection part of the rotation speed of the motor reaches not more than a predetermined value BB.
Description
Technical field
The present invention relates to a kind of electric motor driven power steering system, more particularly, relate to a kind of being used for by can directly imposing on the electric motor driven power steering system that steering system alleviates pilot control work to the rotational force of electrical motor.
Background technology
Electric motor driven power steering system is a kind of electrical motor that is arranged on the steering system that has, so that by using control unit the power that provides from electrical motor to be controlled the system that alleviates pilot control work.
In general electric motor driven power steering system, produce with respect to the auxiliary torque that is input to the steering torque of bearing circle by chaufeur by auxiliary current being transmitted to electrical motor.Auxiliary current is by the incoming signal according to steering torque, the speed of a motor vehicle and motor speed, carry out mainly that following three kinds of processing decide, that is: fundamental current computing, the inertia compensation electric current computing that the electric current of the moment of inertia that is used to offset electrical motor and system is calculated, and the damping compensation electric current computing that the electric current that is used for the restrictions motor rotation is calculated.
Fundamental current computing and the computing of inertia compensation electric current are that basis is from the steering torque signal of manual steering torque detecting unit and the processing of carrying out from the vehicle speed signal of car speed sensor.
The computing of damping compensation electric current is the processing of carrying out according to from the steering torque signal of manual steering torque detecting unit, from the vehicle speed signal and the motor speed of car speed sensor.
Figure 16 is the block scheme that the formation of the damping compensation electric current calculating functional unit in the conventional system is shown.
Forwards/reverse state discrimination function unit 200 is the state-detection of bearing circle forward condition or reverse state according to input torque signal and motor speed signal, and for example adopting L level form or output to handoff functionality unit 201 at reverse state employing H level is form with the corresponding forwards/reverse status signal of state bearing circle at forward condition.
Forward damping compensation electric current calculates functional unit 202 according to input torque signal, vehicle speed signal and motor speed signal, for handoff functionality unit 201 provides forward damping compensation current signal.
Oppositely the damping compensation electric current calculates functional unit 203 according to input torque signal, vehicle speed signal and motor speed signal, for handoff functionality unit 201 provides reverse damping compensation current signal.
Forward damping compensation current signal and the oppositely switching between the damping compensation current signal are carried out in handoff functionality unit 201, when the forwards/reverse status signal is represented to adopt the forward condition of L level form, select forward damping compensation electric current to calculate functional unit 202 sides, when the forwards/reverse status signal is represented to adopt the reverse state of H level form, select reverse damping compensation electric current to calculate functional unit 203 sides, and export respectively forward damping compensation current signal and oppositely the damping compensation current signal as damping compensation current signal Ds.
Figure 17 is the block scheme that the formation of the forwards/reverse state discrimination function unit 200 in the conventional electric motor driven power steering system is shown.Conventional forwards/reverse state discrimination function unit 200 comprises: sign determination functional unit 204, be used for the symbol of the input torque imported is judged, and input torque represent on the occasion of situation under output " 1 ", represent output " 0 " under the situation of negative value at input torque; Sign determination functional unit 205 is used for the symbol of the motor speed imported is judged, and motor speed represent on the occasion of situation under output " 1 ", represent output " 0 " under the situation of negative value at motor speed; And relational calculus functional unit 206, be used under the output of sign determination functional unit 204 and the situation consistent from the output of sign determination functional unit 205, output be in forward condition corresponding " 0 ", from the output of sign determination functional unit 204 with from the inconsistent situation of the output of sign determination functional unit 205 under, export and be in reverse state corresponding " 1 ".
As shown in figure 16, the damping compensation current signal is to calculate according to input torque, the speed of a motor vehicle and motor speed that the bearing circle operation from chaufeur as parameter obtains.Herein, forwards/reverse state discrimination function unit 200 is the condition judgement of bearing circle forward condition or reverse state according to input torque and motor speed as parameter.
On the Light-duty Vehicle of low speed driving, often find, as the bearing circle of attempting to make vehicle oppositely and in the less system of the autoregistration moment of torsion (SAT) of the power of effect, the autoregistration moment of torsion that produces when bearing circle is reverse reduces the mechanical friction power of the gear case of electric motor driven power steering system, thereby it is oppositely blunt to produce bearing circle, and bearing circle can not be backwards to the phenomenon of its straight ahead position and Halfway Stopping.
For this reason, when setting the damping compensation current signal, in order to conduct the compensating current that to offset friction force, when judging reverse state, with for the situation of exporting the reverse damping compensation current signal of exporting in normal high-speed region so that bearing circle is difficult to be backwards to the straight ahead position as the compensating current of the component that from basic auxiliary current, deducts opposite, be designed to export as with the reverse auxiliary current of the component of current of basic auxiliary current addition so that bearing circle is positively reverse.
In addition, as shown in figure 17, during forwards/reverse condition judgement in conventional electric motor driven power steering system is handled, under the symbol of the input torque situation consistent with the symbol of motor speed, commutation is controlled, so that select forward damping compensation current signal, and under the situation that these two symbols differ from one another, select reverse damping compensation current signal (for example, with reference to patent documentation No.1).
[patent documentation No.1]
No. 3137847 Japanese Patent
Figure 18 is turning angle of steering wheel (ANGLE), steering torque (TRQ), motor current (Im) and the time dependent figure of motor speed (MSPD) that the actual vehicle in the low speed driving is shown.In the drawings, transverse axis is represented the time, the longitudinal axis is represented the analog value of deflection angle, motor current and motor speed, wherein, on the occasion of corresponding with the deflection angle, motor current and the motor speed that produce when vehicle is turned right, negative value is corresponding with the deflection angle, motor current and the motor speed that produce when vehicle turns left.In addition, time range O～A is the scope of expression bearing circle forward condition, time range A～B is the scope of expression bearing circle reverse state, and time range B～C is the scope that is illustrated in time dependent bearing circle state after the reverse operating of travel direction dish.
In the drawings, in the scope O～A of expression bearing circle forward condition, turning angle of steering wheel (ANGLE) increases in right (positive dirction), when this happens, be appreciated that, steering torque (TRQ) be on the occasion of the expression of, motor current (Im) on the occasion of, motor speed (MSPD) also represent on the occasion of.At this moment, because the symbol of steering torque (TRQ) is consistent with the symbol of motor speed (MSPD), thereby the processing of the forwards/reverse state discrimination function unit 200 shown in Figure 17 is the condition judgement of bearing circle " forward " state, and forward damping compensation current signal is output.In scope A～B, the expression of turning angle of steering wheel (ANGLE) and steering torque (TRQ) on the occasion of, and motor current (Im) and motor speed (MSPD) change with negative value.Then, because bearing circle is in reverse state, thereby turning angle of steering wheel (ANGLE) is along the direction migration to zero convergence.At this moment, because the symbol of steering torque (TRQ) is different with the symbol of motor speed (MSPD), thereby the forwards/reverse state discrimination function unit shown in Figure 17 is the condition judgement of bearing circle " oppositely " state, and oppositely the damping compensation current signal is output.Herein, because vehicle is in low speed driving, thereby oppositely the damping compensation current signal is output as reverse auxiliary current signal, so that based on from the signal of the output signal of Application of Motor Speed Detecting functional unit with based on signal plus from the output signal of steering torque sensor, thereby play the oppositely directed certain effect of bearing circle that makes.
Yet as can be seen, after a B, turning angle of steering wheel (ANGLE) can smooth-goingly not be backwards to the straight ahead position when browsing Figure 18, and in time range B～C, (ANGLE) is non-vanishing for turning angle of steering wheel, but is parked in certain deflection angle.This is the phenomenon that takes place when the mechanical friction power of the gear case of electric motor driven power steering system surpasses the autoregistration moment of torsion (SAT) of vehicle, and at this moment, steering torque (TRQ) crosses over zero, and its sign modification becomes consistent with the symbol of motor speed (MSPD).This has judged that bearing circle is in forward condition, and has stopped the output of reverse damping compensation current signal or the oppositely output of auxiliary current signal, and like this, restoring force loses, and bearing circle becomes certain angle to stop with the straight ahead position.Like this, according to conventional forwards/reverse determination processing, a problem of generation is to turn to sense significantly to worsen, as expressed by " the bearing circle return is bad " or " turning to the sense irregularity ".
Summary of the invention
In order to address the above problem, the purpose of this invention is to provide a kind of electric motor driven power steering system, it can realize the smooth-going reverse of bearing circle, and can provide the smooth-going sense that turns to, thereby when bearing circle is backwards to its straight ahead position, the risk of Halfway Stopping in the time of bearing circle can not take place becoming certain angle with its straight ahead position.
In order to achieve the above object, electric motor driven power steering system according to the present invention constitutes as described below.
First electric motor driven power steering system (corresponding with a first aspect of the present invention) is provided, and this first electric motor driven power steering system comprises: steering torque sensor is used for the steering torque of vehicle steering system is detected; Car speed sensor is used for car speed is detected; Electrical motor is used for turning to auxiliary torque additional to steering system; Motor speed computing function unit is used for motor speed is calculated; And motor controller, be used at least according to setting the target current value that is used to be transmitted to electrical motor by the detected steering torque of steering torque sensor, and output is used for the control signal of driving motor, this motor controller comprises: forwards/reverse state discrimination function unit is used for according to the positive and negative of steering torque and motor speed the forward condition or the reverse state of steering system being judged; And arithmetic and logic unit, be used under the situation of reverse state, based on from the signal of the output signal of motor speed computing function unit with based on signal plus from the output signal of steering torque sensor, thereby oppositely control according to output signal from arithmetic and logic unit, this electric motor driven power steering system is characterised in that, steering system be judged to be by forwards/reverse state discrimination function unit be in reverse state after, forwards/reverse state discrimination function unit continues to keep reverse state, reduces to predetermined value or following up to the absolute value of the motor speed that is calculated by motor speed computing function unit.
According to first electric motor driven power steering system, since steering system be judged to be by forwards/reverse state discrimination function unit be in reverse state after, forwards/reverse state discrimination function unit continues to keep reverse state, absolute value up to the motor speed that is calculated by motor speed computing function unit is reduced to predetermined value or following, thereby by adopting a kind of formation of not using expensive steering angle sensor to use steering torque and motor speed data, even when bearing circle is reverse in vehicle low speed turns to, steering torque crosses over zero, so that be under this condition in its sign modification one-tenth relation consistent with the symbol of motor speed, forwards/reverse state discrimination function unit does not judge at once that also the state of bearing circle is in forward condition, but the judgement that continues to keep reverse state, up to satisfying certain condition, like this, when low vehicle speeds, in the bearing circle reverse operating, bearing circle can almost be backwards to the straight ahead position and non-Halfway Stopping, turns to sense thereby significantly improve.
Second electric motor driven power steering system (corresponding with a second aspect of the present invention) is provided, and this second electric motor driven power steering system comprises: steering torque sensor is used for the steering torque of vehicle steering system is detected; Car speed sensor is used for car speed is detected; Electrical motor is used for turning to auxiliary torque additional to steering system; Motor speed computing function unit is used for motor speed is calculated; And motor controller, be used at least according to setting the target current value that is used to be transmitted to electrical motor, and output is used for the control signal of driving motor by the detected steering torque of steering torque sensor; Motor controller comprises: forwards/reverse state discrimination function unit is used for according to the positive and negative of steering torque and motor speed the forward condition or the reverse state of steering system being judged; And arithmetic and logic unit, be used under the situation of reverse state, based on from the signal of the output signal of motor speed computing function unit with based on signal plus from the output signal of steering torque sensor, thereby oppositely control according to output signal from arithmetic and logic unit, this electric motor driven power steering system is characterised in that, steering system be judged to be by forwards/reverse state discrimination function unit be in reverse state after, forwards/reverse state discrimination function unit continues to keep reverse state, up to reducing to predetermined value or following by the detected speed of a motor vehicle of car speed sensor.
According to second electric motor driven power steering system, since steering system be judged to be by forwards/reverse state discrimination function unit be in reverse state after, forwards/reverse state discrimination function unit continues to keep reverse state, up to reducing to predetermined value or following by the detected speed of a motor vehicle of car speed sensor, thereby by adopting a kind of formation of not using expensive steering angle sensor to use steering torque and motor speed data, even when bearing circle is reverse in vehicle low speed turns to, steering torque crosses over zero, so that be under this condition in its sign modification one-tenth relation consistent with the symbol of motor speed, the state that forwards/reverse state discrimination function unit also is not judged to be bearing circle at once is in forward condition, but the judgement that continues to keep reverse state, up to satisfying certain condition, like this, when low vehicle speeds, in the bearing circle reverse operating, bearing circle can almost be backwards to the straight ahead position and non-Halfway Stopping, and along with the speed of a motor vehicle increases, locking is disengaged, and turns to sense thereby significantly improve.
Description of drawings
Fig. 1 illustrates the figure that the typical case according to the electric motor driven power steering system of the embodiment of the invention constitutes.
Fig. 2 is the figure that illustrates according to the control unit of the electric motor driven power steering system of the embodiment of the invention.
Fig. 3 illustrates the block scheme that target current is determined the formation of functional unit.
Fig. 4 is the block scheme that the formation of controllable function unit is shown.
Fig. 5 is the block scheme of formation that the first concrete example of forwards/reverse state discrimination function unit is shown.
Fig. 6 illustrates the block scheme that reverse damping compensation electric current calculates the formation of functional unit.
Fig. 7 is the figure with the corresponding reverse damping fundamental current value of motor speed.
Fig. 8 is the figure with the corresponding motor speed deviant of the speed of a motor vehicle.
Fig. 9 is the figure with the corresponding speed of a motor vehicle ratio of the speed of a motor vehicle.
Figure 10 is and the corresponding figure that oppositely assists ratio of the speed of a motor vehicle.
Figure 11 is the figure with the corresponding speed of a motor vehicle torque ratio of the speed of a motor vehicle.
Figure 12 is the figure with the corresponding torque ratio of moment of torsion.
Figure 13 is the figure with the corresponding reverse auxiliary torque ratio of moment of torsion.
Figure 14 is illustrated in the actual vehicle low speed driving, the time dependent figure of turning angle of steering wheel, steering torque, motor current and motor speed that produces when using according to electric motor driven power steering system of the present invention.
Figure 15 is the block scheme of formation that the second concrete example of forwards/reverse state discrimination function unit is shown.
Figure 16 is the block scheme that the formation of the damping compensation electric current calculating functional unit in the conventional electric motor driven power steering system is shown.
Figure 17 is the block scheme that the formation of the forwards/reverse state discrimination function unit in the conventional electric motor driven power steering system is shown.
Figure 18 is illustrated in the actual vehicle low speed driving, the time dependent figure of turning angle of steering wheel, steering torque, motor current and motor speed that produces when using conventional electric motor driven power steering system.
The specific embodiment
Below will be with reference to the accompanying drawings, the preferred embodiments of the present invention are described.
Fig. 1 illustrates the figure that the typical case according to the electric motor driven power steering system of the embodiment of the invention constitutes.In electric motor driven power steering system 10, the manual steering moment of torsion produce mechanism 16 be by the gear 15a of rack and-pinion mechanism 15 via the adapter shaft 13 with universal-joint 13a, 13b be wholely set steering shaft 12 on bearing circle 11 and be connected and constitute.
Rack shaft 17 has and gear 15a ingear rack tooth 17a, and when the engagement by gear 15a and rack tooth 17a of rotatablely moving of bearing circle is transformed into crank motion, rack shaft 17 is reciprocating, and this rack shaft 17 is connected with left and right sides front-wheel 19 as rotor wheel by tierod 18 at its two ends.Chaufeur produces mechanism 16 via the manual steering moment of torsion and shakes front-wheel with normal tooth bar-gear steering swivel system, to change vehicle heading by direction of operating dish 11.
For example be provided with the electrical motor 20 that is used to provide auxiliary torque (turning to auxiliary torque) coaxially with rack shaft 17, produce the steering torque that mechanism 16 produces to reduce by the manual steering moment of torsion, and by the ball screw framework 21 that be arranged in parallel substantially with rack shaft 17, the auxiliary torque that is provided by rotatablely moving of electrical motor 20 is transformed into and is used for straight-line power, and this masterpiece is used on the rack shaft 17 then.
Drive side helical wheel 20a is wholely set on the rotor of electrical motor 20.This helical wheel 20a and the helical wheel 21b of leading screw 21a one end that is wholely set at ball screw framework 21 mesh.In addition, the nut of ball screw framework 21 is connected with rack shaft 17.
Fig. 2 is the figure that the control unit of electric motor driven power steering system is shown.In Fig. 1, in unshowned steering box, be provided with and be used for manual steering torque detecting unit 22 that the manual steering moment of torsion that acts on the gear 15a is detected.22 of this manual steering torque detecting units are transformed into manual steering moment of torsion detection signal Td by its detected manual steering torque T, and the manual steering moment of torsion detection signal Td that conversion like this is come is input in the control unit 24.In addition, on vehicle, also be provided with the car speed sensor that is used for detecting with the corresponding vehicle speed signal v of vehicle speed, so that vehicle speed signal v is input in the control unit 24.
And, as shown in Figure 2, in electric motor driven power steering system 10, be provided with motor current detecting unit 25.This motor current detecting unit 25 has the resistance that is connected in series with electrical motor 20, and the actual size and Orientation that is transmitted to the motor current IM of electrical motor 20 is detected.Then, 25 of motor current detecting units are input in the control unit 24 with the corresponding motor current signal of motor current IM Im.
And, as shown in Figure 2, in electric motor driven power steering system 10, be provided with motor voltage detecting unit 26.Motor voltage detecting unit 26 detects the voltage at electrical motor 20 two ends respectively, and the actual size and Orientation that imposes on the motor voltage VM of electrical motor 20 is detected.Then, 26 of motor voltage detecting units are input to control unit 24 with the corresponding motor voltage signal of motor voltage VM Vm.
Each detection signal Td, v of manual steering torque detecting unit 22, car speed sensor 23, motor current detecting unit 25 and motor voltage detecting unit 26, Im, Vm are imported into control unit 24.Then, control unit 24 determines to be transmitted to the size and Orientation of the motor current IM of electrical motor 20 according to detection signal Td, v, Im, Vm, so that operating motor, and to controlling by the power (turning to auxiliary torque) of electrical motor output.
Because the detection signal from manual steering torque detecting unit 22, car speed sensor 23, motor current detecting unit 25 and motor voltage detecting unit 26 is imported into control unit 24 as analog signal, thereby, so the analog signal of input then is transformed into digital signal by unshowned mould/transformation of variables functional unit, then, so the next digital signal of conversion is captured to corresponding C PU.
Fig. 3 illustrates the block scheme that target current is determined the formation of functional unit 27.Target current determines that functional unit 27 mainly comprises: motor speed computing function unit (motor speed computer device) 29, fundamental current computing function unit 30, the inertia compensation electric current calculates functional unit 31, the damping compensation electric current calculates functional unit 32, inertia compensation functional unit 33, damping compensation functional unit 34, target current are finally determined functional unit 35, low-pass filter 36, phase compensation functional unit 37 and high-pass filter 38.
Motor speed computing function unit 29 receives respectively motor current signal Im and the motor voltage signal Vm from motor current detecting unit 25 and 26 inputs of motor voltage detecting unit, and motor speed signal Nm is outputed to damping compensation electric current calculating functional unit 32.
Steering torque signal Td from manual steering torque detecting unit 22 passes through low-pass filter 36, carry out phase compensation by phase compensation functional unit 37 then, to be transformed into steering torque signal Ts, and fundamental current computing function unit 30 receives steering torque signal Ts that so obtains and the vehicle speed signal V that imports from car speed sensor 23, and target current signal IMS is outputed to inertia compensation functional unit 33.Fundamental current computing function unit 30 is read and the steering torque signal Ts and the corresponding target current signal of the vehicle speed signal V IMS that are used as the address according to the data of setting according to experiment value or setting value in advance that are used to comprise steering torque signal Ts and vehicle speed signal V and cooresponding target current signal IMS.Notice that target current signal IMS comprises the relevant information that constitutes the electric current of benchmark aspect the target motor current that is transmitted to electrical motor 20 is set.
The inertia compensation electric current calculates functional unit 31 and is used to carry out the inertia compensation electric current computing that the moment of inertia that is used for calculating motor and system is offset the electric current of usefulness, reception by make the signal TI that obtains through low-pass filter 36 from the steering torque signal Td of manual steering torque detecting unit 22, by making signal TI pass through steering torque signal Th that high-pass filter 38 obtains and from the vehicle speed signal V of car speed sensor 23, and inertia compensation signal IS is outputed to inertia compensation functional unit 33.At first, the inertia compensation electric current calculates 31 couples of steering torque signal Th of functional unit, TI seeking time differential, and calculates the time diffusion value of steering torque.Then, the inertia compensation electric current calculate functional unit 31 according in advance according to experiment value or setting value being used to of setting comprise the time diffusion value of steering torque and vehicle speed signal V and with the data of the cooresponding inertia compensation signal of this time diffusion value IS, read and time diffusion value and the corresponding inertia compensation signal of vehicle speed signal V IS as the steering torque of address.
The damping compensation electric current calculates functional unit 32 and is used to calculate the electric current that is used for the restrictions motor rotation, reception is from the motor speed signal Nm of motor speed computing function unit 29, from the vehicle speed signal V and the steering torque signal TI of car speed sensor 23, and damping compensation current signal DS is outputed to damping compensation functional unit 34.
Inertia compensation functional unit 33 receives respectively and calculates the target current signal IMS and the inertia compensation signal IS of functional unit 31 inputs from fundamental current computing function unit 30 and inertia compensation electric current, and compensation target current signal IMS ' is outputed to damping compensation functional unit 34.
Damping compensation functional unit 34 receives respectively and calculates compensation target current signal IMS ' and the damping compensation current signal DS of functional unit 32 inputs from inertia compensation functional unit 33 and damping compensation electric current, and compensation target current signal IMS " output to the finally definite functional unit 35 of target current.
Target current determines that finally functional unit 35 receives respectively the compensation target current signal IMS from damping compensation functional unit 34 and 37 inputs of phase compensation functional unit " and phase compensation steering torque signal Ts, and export target current signal IT.
Fig. 4 is the block scheme that the formation of controllable function unit 28 is shown.Controllable function unit 28 comprises: electric motor operated controllable function unit 39, direct motor drive functional unit 40 and motor current detecting unit 25.
Electric motor operated controllable function unit 39 comprises: feedback (F/B) controllable function unit 40a, feedforward (F/F) controllable function unit 41 and pwm signal systematic function unit 42.Feedback control function unit 40a is made of deviation calculation function unit 43 and deviation current control functional unit 44.
Deviation calculation function unit 43 obtains at the target current signal IT that determines functional unit 27 outputs from target current and from the deviation between the motor current signal Im of motor current detecting unit 25, and the deviate that output so obtains is as deviation signal 43a.
Deviation current control functional unit 44 is made of ratio parts, integrating block and additive operation functional unit, output has been made the signal 43a ' that ratio is handled to the deviation signal 43a that is imported at the ratio parts, the signal 43a of Integral Processing has been made in output at integrating block "; at the additive operation functional unit signal 43a ' and signal 43a " added together, and generate and export deviation current controling signal 44a, make that the value of deviation signal 43a is approaching zero as duty cycle signals.
Feed forward control functional unit 41 is used for generating and output feed forward control key element, and comprises: feedforward ratio parts 45, killer 46 and additive operation functional unit 47.Feedforward ratio parts 45 are used for exporting and the proportional F/F signal of the target current signal IT 45a that is imported according to certain any F/F gain (Kff), killer 46 is used under F/F signal 45a remains on situation in the preset range, as-is condition output F/F signal 45a, and under the situation of F/F signal 45a outside preset range, restriction F/F signal 45a is to export the signal of any steady state value.
That is to say, under the value of the target current signal IT that is input to feedforward ratio parts 45 remains on situation in the preset range, the killer 46 of feed forward control functional unit 41 gains according to above-mentioned F/F, output has the duty cycle signals with the proportional value of target current signal IT, and under the value of target current signal IT was positioned at situation outside the preset range, killer 46 outputs had the duty cycle signals of any steady state value.Note, be called as feed-forward control signals 46a from the output signal of killer 46.
Additive operation functional unit 47 is feed-forward control signals 46a and the deviation current controling signal 44a addition of exporting from deviation current control functional unit 44 from killer 46 outputs, and the output value that obtains like this, as the final output duty cycle signal 47a that is used for the dutycycle of pwm signal is determined, pwm signal carries out PWM control to the motor current that offers electrical motor 20.
Pwm signal systematic function unit 42 generates according to final output duty cycle signal 47a and is used for electrical motor 20 is carried out the pwm signal that PWM (pulse duration modulation) drives, and the pwm signal that output so generates is as drive control signal 42a.This pwm signal 42a is the signal with dutycycle of being determined by final output duty cycle signal 47a.
Direct motor drive functional unit 40 shown in Figure 4 comprises: grid drive circuit functionality unit 48, and motor drive circuit 49, four power field effect transistors connect by H type bridgt circuit structure therein.Grid drive circuit functionality unit 48 is based on drive control signal (pwm signal) 42a, select two field effect transisters according to the steering direction of bearing circle, and drive so grid of two field effect transisters of selection, so that these field effect transisters are carried out switching manipulation.
The voltage that motor current detecting unit 25 produces according to the two ends at the divert shunt resistor 50 that is connected in series with motor drive circuit 49, motor current (armature current) value IM by electrical motor 20 conduction is detected, and output motor current signal Im.
Like this, control unit 24 bases are by manual steering torque detecting unit 22 detected manual steering torque T, vehicle velocity V, motor current IM and motor voltage IV, the electric current that offers electrical motor 20 from battery supply 51 is carried out PWM control, and to controlling by the power (turning to auxiliary torque) of electrical motor 20 outputs.
In addition, as shown in Figure 4, the voltage that control unit 24 produces according to the two ends at the divert shunt resistor 50 that is connected in series with motor drive circuit 49, motor current value IM by electrical motor 20 conduction detects as motor current signal Im to reality, and in the controllable function unit 28 controlled resets that carry out based on motor current signal Im, thereby further improve the controller characteristic curve of electrical motor 20.
And, control unit 24 is by being input to feedforward ratio parts 45 to target current signal IT, and in additive operation functional unit 47 feed-forward control signals 46a and deviation current controling signal 44a additions from killer 46 outputs, 28 carry out feed forward control in the controllable function unit, thereby further improve the controller characteristic curve of electrical motor 20.
Fig. 5 is the block scheme that illustrates according to the formation of the first concrete example that is used for forwards/reverse state discrimination function unit that forward state or reverse state are judged of the present invention.Forwards/reverse state discrimination function unit 60 comprises: sign determination functional unit 61, sign determination functional unit 62, relational calculus functional unit 63 and latch processing function unit 64A.Latching processing function unit 64A comprises: absolute calculation functional unit 64, predetermined value memory function unit 65, predetermined value memory function unit 66, relational calculus functional unit 67, relational calculus functional unit 68, logic operation functional unit 69, logic operation functional unit 70, preceding value memory function unit 71, logic operation functional unit 72, predetermined value memory function unit 73, predetermined value memory function unit 74, relational calculus functional unit 75, relational calculus functional unit 76, logic operation functional unit 77 and handoff functionality unit 78.
The steering torque signal (TRQ) that 61 pairs of sign determination functional units are input to it be on the occasion of or negative value judge, on the occasion of situation under, 61 outputs " 1 " of sign determination functional unit, under the situation of negative value, 61 outputs " 0 " of sign determination functional unit.The motor speed signal (MSPD) that 62 pairs of sign determination functional units are input to it be on the occasion of or negative value judge, on the occasion of situation under, 62 outputs " 1 " of sign determination functional unit, under the situation of negative value, 62 outputs " 0 " of sign determination functional unit.63 pairs of relational calculus functional units carry out computing from the value of sign determination functional unit 61,62 inputs is whether consistent each other, under the consistent each other situation of the value of so input, 63 outputs " 0 " of relational calculus functional unit, under the inconsistent each other situation of these values, 63 outputs " 1 " of relational calculus functional unit.
The absolute value that 64 pairs of absolute calculation functional units are input to its motor speed (MSPD) carries out computing, and exports this absolute value.The first predetermined value AA is stored in predetermined value memory function unit 65, and this value is outputed to relational calculus functional unit 67.Relational calculus functional unit 67 compares the output and the first predetermined value AA from absolute calculation functional unit 64, be equal to or greater than at absolute value under the situation of predetermined value AA, 67 outputs " 1 " of relational calculus functional unit, under the situation of absolute value less than predetermined value AA, 67 outputs " 0 " of relational calculus functional unit.
Predetermined value memory function unit 66 storing predetermined values are zero, and predetermined value zero is outputed to relational calculus functional unit 68.Relational calculus functional unit 68 is oppositely damping ratio and predetermined value zero compare, under the reverse situation of damping ratio greater than predetermined value zero, 68 outputs " 1 " of relational calculus functional unit are equal to or less than under the situation of predetermined value zero in reverse damping ratio, 68 outputs " 0 " of relational calculus functional unit.Logic operation functional unit 69 receives from the output of relational calculus functional unit 63,67,68 inputs, and logic product is carried out computing and exported this logic product.
70 pairs of logic operation functional units are from the value of preceding value memory function unit 71 with from the logic of logic operation functional unit 69 outputs with carry out computing and with its output.The data that preceding value memory function unit 71 output obtains before carrying out current sampling and with current sampling next-door neighbour's sampling the time, that is to say, the output valve from logic operation functional unit 72 that produces in the before pre-processing is stored, and the value of being stored is being output in pre-processing.The output that logic operation functional unit 72 receives from logic operation functional unit 70,77 is carried out computing and is exported this logic product logic product.
73 storages of predetermined value memory function unit are also exported the second predetermined value BB.Relational calculus functional unit 75 compares the value and the second predetermined value BB from absolute calculation functional unit 64, be equal to or less than at absolute value under the situation of the second predetermined value BB, 75 outputs " 1 " of relational calculus functional unit, under the situation of absolute value greater than the second predetermined value BB, 75 outputs " 0 " of relational calculus functional unit.74 storages of predetermined value memory function unit and output predetermined value zero.Relational calculus functional unit 76 is oppositely damping ratio and predetermined value zero compare, under the situation that oppositely damping ratio and predetermined value zero are consistent each other, 76 outputs " 1 " of relational calculus functional unit, under reverse damping ratio and the inconsistent each other situation of predetermined value zero, 76 outputs " 0 " of relational calculus functional unit.
Logic operation functional unit 77 receives from the output of relational calculus functional unit 75,76 inputs, and carries out nondisjunction or NOR computing.The 78 pairs of switchings in handoff functionality unit are controlled, make that in the output from logic operation functional unit 72 be under the situation of " 1 ", output is from the output of logic operation functional unit 72, and be under the situation of " 0 " in the output from logic operation functional unit 72, the output from logic operation functional unit 72 is switched to output from relational calculus functional unit 63.
Below, will the operation of forward/reverse state decision-making function unit 60 be described.
Be in reverse state at bearing circle, motor speed (MSPD) is equal to or greater than desired speed AA rps (first predetermined value), and under the oppositely auxiliary condition of the value beyond the output employing zero (the figure center A of portion) than (SUBRTO), from 61 outputs " 1 " of sign determination functional unit, and from 62 outputs " 0 " of sign determination functional unit.As a result, from 63 outputs " 1 " of relational calculus functional unit.From 67 outputs " 1 " of relational calculus functional unit, and from 68 outputs " 1 " of relational calculus functional unit.As a result, from 69 outputs " 1 " of logic operation functional unit, and from 70 outputs " 1 " of logic operation functional unit.From 76 outputs " 0 " of relational calculus functional unit, and from 75 outputs " 0 " of relational calculus functional unit.As a result, from 77 outputs " 1 " of logic operation functional unit.Thus, from 72 outputs " 1 " of logic operation functional unit, and the output from logic operation functional unit 72 is output from handoff functionality unit 78 as the output from forwards/reverse state discrimination function unit, thereby keeps (latching) in reverse state judging.
Herein, oppositely auxiliary than being in reverse damping compensation electric current calculating functional unit parameters calculated described later, and can change according to vehicle velocity V EL.On the experience, in about 30km/h or slower low speed of a motor vehicle zone, set the arbitrary value beyond zero, wanting to make in the invalid speed of a motor vehicle zone of reverse aux. controls, perhaps greatly also can ignore in the speed of a motor vehicle zone of the frictional influence in the electric motor driven power steering gear case at SAT, that is: do not have at bearing circle and anyly auxiliary just can be backwards to about 30km/h of straight ahead position or faster in the speed of a motor vehicle zone, reverse assist more zero than setting for.
Below satisfying during arbitrary condition, latch mode is cancelled or is disengaged: the rotating speed of bearing circle equals or is slower than desired speed, that is: motor speed (MSPD) equals or is slower than desired speed BB rps (second speed predetermined value), and perhaps oppositely auxiliary is zero (the figure center C of portion) than (SUBRTO).Herein, the first predetermined value AA is the value greater than the second predetermined value BB.That is to say, from 61 outputs " 0 " of sign determination functional unit, and from 62 outputs " 0 " of sign determination functional unit.As a result, from 63 outputs " 0 " of relational calculus functional unit.From 67 outputs " 0 " of relational calculus functional unit, and from " 0 " of logic operation functional unit 69 outputs as logic product.From 68 outputs " 0 " of relational calculus functional unit, from 75 outputs " 1 " of relational calculus functional unit, from 76 outputs " 1 " of relational calculus functional unit, and from " 0 " of logic operation functional unit 77 outputs as nondisjunction.In addition, owing to when before sampling, have latch mode, thereby 71 outputs " 1 " from preceding value memory function unit, and from 70 outputs " 1 " of logic operation functional unit.Then, export " 0 " from logic operation functional unit 72, and handoff functionality unit 78 is switched, so that output is from the output of relational calculus functional unit 63.As a result, the forward condition signal is output.
Under the condition beyond the condition that reverse state is latched, that is: under the condition of logic operation functional unit 72 outputs " 0 ", output from relational calculus functional unit 63 is output as the output from forwards/reverse state discrimination function unit, and it is the same with conventional determination processing, the direction of bearing circle is decided by the direction (symbol) of steering torque and the direction (symbol) of motor speed, under the identical situation of symbol, the expression direction, and under the different situation of symbol, expression inverse direction (the figure center D of portion).
Fig. 6 illustrates the block scheme that reverse damping compensation electric current calculates the control of functional unit 80.Oppositely damping compensation electric current calculating functional unit 80 comprises: motor speed skew calculation function unit 81, reverse damping fundamental current mapping function unit 82, the speed of a motor vehicle is than mapping function unit 83, oppositely auxiliary than mapping function unit 84, speed of a motor vehicle torque ratio mapping function unit 85, torque ratio mapping function unit 86, oppositely auxiliary torque is than mapping function unit 87, subtraction function unit 88, oppositely auxiliary offset storage functional unit 89, subtraction function unit 90, ratio parts 91, killer 92, multiplication function unit 93, multiplication function unit 94, multiplication function unit 95, multiplication function unit 96,97, and subtraction function unit 98.
Oppositely damping fundamental current mapping function unit 82 has such memory device such as ROM, in memory device, store in advance according to experimental result or the logic operation motor speed that comprises 88 outputs that set, shown in Figure 7 and the data of cooresponding reverse damping fundamental current value from the subtraction function unit, and oppositely damping fundamental current mapping function unit 82 is designed to select and be input to its corresponding reverse damping fundamental current value of digital conversion motor speed, so that the reverse damping fundamental current value of so selecting is outputed to multiplication function unit 93.
Motor speed skew calculation function unit 81 has such memory device such as ROM, in memory device, store in advance according to experimental result or the logic operation data that comprise the speed of a motor vehicle and cooresponding motor speed deviant that set, shown in Figure 8, and motor speed skew calculation function unit 81 is designed to select and be input to its corresponding motor speed deviant of the digital conversion speed of a motor vehicle, so that the motor speed deviant of so selecting is outputed to subtraction function unit 88.
The speed of a motor vehicle has such memory device such as ROM than mapping function unit 83, in memory device, store in advance according to experimental result or the logic operation data that comprise the speed of a motor vehicle and cooresponding speed of a motor vehicle ratio that set, shown in Figure 9, and the speed of a motor vehicle is designed to select and the corresponding speed of a motor vehicle ratio of the digital conversion speed of a motor vehicle that is input to it than mapping function unit 83, so that the speed of a motor vehicle specific output of so selecting is arrived multiplication function unit 93.
Oppositely auxiliary have such memory device such as ROM than mapping function unit 84, in memory device, store in advance according to experimental result or the logic operation data that comprise vehicle velocity V and cooresponding oppositely auxiliary ratio that set, shown in Figure 10, and oppositely assist than mapping function unit 84 and be designed to select and the corresponding oppositely auxiliary ratio of the digital conversion vehicle velocity V that is input to it, so that the oppositely auxiliary ratio of so selecting is not only outputed to multiplication function unit 96, and outputs to forwards/reverse state discrimination function unit.
Speed of a motor vehicle torque ratio mapping function unit 85 has such memory device such as ROM, in memory device, store in advance according to experimental result or the logic operation data that comprise the speed of a motor vehicle and cooresponding speed of a motor vehicle torque ratio that set, shown in Figure 11, and speed of a motor vehicle torque ratio mapping function unit 85 is designed to select and be input to its corresponding speed of a motor vehicle torque ratio of the digital conversion speed of a motor vehicle, so that the speed of a motor vehicle torque ratio of so selecting is outputed to multiplication function unit 95.
Torque ratio mapping function unit 86 has such memory device such as ROM, in memory device, store in advance according to experimental result or the logic operation data that comprise moment of torsion and cooresponding torque ratio that set, shown in Figure 12, and torque ratio mapping function unit 86 is designed to select and be input to its corresponding torque ratio of digital conversion moment of torsion, so that the torque ratio of so selecting is outputed to multiplication function unit 94.
Oppositely auxiliary torque has such memory device such as ROM than mapping function unit 87, in memory device, store in advance according to experimental result or the logic operation data that comprise moment of torsion and cooresponding reverse auxiliary torque ratio that set, shown in Figure 13, and oppositely auxiliary torque is designed to select and the corresponding reverse auxiliary torque ratio of the digital conversion moment of torsion that is input to it than mapping function unit 87, so that the reverse auxiliary torque specific output of so selecting is arrived multiplication function unit 97.
The figure center A of portion represents reverse auxiliary current computing function unit.For the input value at motor speed MSPD is provided with the blind area to avoid such as the interference of noise etc. and the influence of unstable key element, deduct deviant CC (rps) as the output valve of coming the auxiliary offset storage functional unit 89 of self-reversal in subtraction function unit 90, and multiplying each other with a reverse auxiliary current gain K (A/rps) from the output valve of subtraction function unit 90.This value is only by the necessary current value of kinetic force of friction in the gear case of the ceiling restriction device in the square frame 92 compensation electric motor driven power steering systems, and its maxim is restricted.Herein, current value is set as 1.5A.Afterwards, serve as that set at interval reverse assisted than (SUBRTO) reverse auxiliary the inquiry with the 1km/h speed of a motor vehicle according to the speed of a motor vehicle than mapping function unit 84, in multiplication function unit 96 value that so inquires and current value are multiplied each other then.
And, multiply by in multiplication function unit 97 from reverse auxiliary torque than 87 outputs of mapping function unit and by the reverse auxiliary torque ratio of steering torque TRQ reference, so that finally obtain reverse auxiliary current.Herein, in the speed of a motor vehicle zone of the reverse auxiliary current of desired output, mainly be in the low vehicle speed range of 0～30km/h, oppositely auxiliary than the arbitrary value of setting for beyond zero.At 30km/h or faster in the speed of a motor vehicle zone,, so that the normal oppositely damping compensation electric current of output, and a reverse damping ratio set for zero in addition arbitrary value oppositely auxiliary than setting zero for.
In vehicle ', judging that bearing circle is under the situation of reverse state, oppositely damping compensation becomes effective by above determination processing, and particularly when low vehicle speeds, oppositely auxiliary current is output as the damping compensation electric current, and in higher speed of a motor vehicle zone, oppositely the damping compensation electric current is output as the damping compensation electric current.
Figure 14 is illustrated in deflection angle or turning angle of steering wheel (ANGLE), steering torque (TRQ), motor current (Im) and the time dependent figure of motor speed (MSPD) according to the bearing circle of electric motor driven power steering system of the present invention that produces in the actual vehicle low speed driving.In the drawings, transverse axis is represented the time, the longitudinal axis is represented the analog value of deflection angle, motor current and motor speed, wherein, on the occasion of corresponding with the deflection angle, motor current and the motor speed that produce when vehicle is turned right, negative value is corresponding with the deflection angle, motor current and the motor speed that produce when vehicle turns left.In addition, time range O～A is the scope of expression bearing circle forward condition, and time range A～B is the scope of expression bearing circle reverse state, and time range B～C is the scope that is illustrated in time dependent bearing circle state after the reverse operating of travel direction dish.
In the drawings, in the scope O～A of expression bearing circle forward condition, with conventional example class shown in Figure 180 seemingly, turning angle of steering wheel (ANGLE) increases along direction (positive dirction) to the right, when this happens, be appreciated that motor current (Im) expression on the occasion of, motor speed (MSPD) also represent on the occasion of.At this moment, in Fig. 5, from 61 outputs " 1 " of sign determination functional unit, and from 62 outputs " 1 " of sign determination functional unit.The result, from 63 outputs " 0 " of relational calculus functional unit, thereby from 69 outputs " 0 " of logic operation functional unit, owing to when before sampling, there is not latch mode, that is: preceding value memory function unit 71 is in " 0 ", thereby from logic operation functional unit 72 output " 0 ", and the 78 pairs of switchings in handoff functionality unit control, and make that the output from relational calculus functional unit 63 is output as the output from forwards/reverse state discrimination function unit.At this moment, the processing in the forwards/reverse state discrimination function unit shown in Fig. 5 produces " forward " condition judgement, and forward damping compensation current signal is output.
In scope A～B, turning angle of steering wheel and steering torque be on the occasion of, and motor current and motor speed change with negative value.At this moment, from 61 outputs " 1 " of sign determination functional unit, and from 62 outputs " 0 " of sign determination functional unit.As a result, from 63 outputs " 1 " of relational calculus functional unit.In addition, when the absolute value of motor speed is equal to or less than the first predetermined value AA, becomes " 0 " from the output of relational calculus functional unit 67, and become " 0 " from the output of logic operation functional unit 69.Then, owing to when before sampling, there is not latch mode, that is: preceding value memory function unit 71 is in " 0 ", thereby becomes " 0 " from the output of logic operation functional unit 70, and also becomes " 0 " from the output of logic operation functional unit 72.As a result, handoff functionality unit 78 is controlled, so that output is from the output of relational calculus functional unit 63.Then, because bearing circle is in reverse state, thereby turning angle of steering wheel is to move to the mode of zero convergence.At this moment, the judgement of forwards/reverse state discrimination function unit provides " oppositely " condition judgement, and oppositely the damping compensation current signal is output.Herein, because low vehicle speeds, thereby oppositely the damping compensation current signal is output as reverse auxiliary current, and by realize based on from the signal of the output signal of Application of Motor Speed Detecting functional unit with based on additive operation from the signal plus of the output signal of steering torque sensor, produce and be used to make the certain oppositely directed effect of bearing circle.
Be in output under the state of " 1 ", when motor speed is equal to or greater than first predetermined value, become " 1 " from the output of relational calculus functional unit 67 from relational calculus functional unit 63.In addition, when oppositely auxiliary than being in low speed but when not being zero, become " 1 " from the output of relational calculus functional unit 68, the result becomes " 1 " from the output of logic operation functional unit 69.In addition, become " 1 " from the output of logic operation functional unit 70, irrelevant with the value of preceding value memory function unit 71.In addition, because motor speed is not less than the second predetermined value BB, thereby from 75 outputs " 0 " of relational calculus functional unit.In addition, be 0 owing to oppositely assist, thereby be output as " 0 " from relational calculus functional unit 76 than not.As a result, the output from the logic operation functional unit 77 that carries out NOR-operation becomes " 1 ".Like this, the output from logic operation functional unit 72 becomes " 1 ".Thus, handoff functionality unit 78 is switched, so that output is from the output of logic operation functional unit 72.At this moment, the output valve of logic operation functional unit 72 is stored in the preceding value memory function unit 71, thereby produces latch mode.
After a B reached, steering torque was represented negative value, and motor speed is also represented negative value.At this moment, represent " 0 ", and represent " 0 " from the output of sign determination functional unit 62 from the output of sign determination functional unit 61.As a result, become " 0 " from the output of relational calculus functional unit 63, thereby become " 0 " from the output of logic operation functional unit 69.In addition, at this moment, owing to be output as " 0 " from preceding value memory function unit 71, thereby become " 1 " from the output of logic operation functional unit 70.And, because motor speed is greater than the second predetermined value BB, thereby be output as " 0 " from relational calculus functional unit 75, and because oppositely auxiliary than not being zero, thereby become " 0 ", and from 77 outputs " 1 " of logic operation functional unit from the output of relational calculus functional unit 76.As a result, from 72 outputs " 1 " of logic operation functional unit, and 78 outputs of handoff functionality unit are from the output of logic operation functional unit 72.That is to say that latch mode continues, thereby be appreciated that turning angle of steering wheel converges to zero.
And, because motor speed becomes in time less than the second predetermined value BB, thereby become " 1 " from the output of relational calculus functional unit 75, and owing to become " 1 ", thereby become " 0 " from the output of the logic operation functional unit 77 that is used to carry out NOR-operation from the output of logic operation functional unit 76.As a result, become " 0 " from the output of logic operation functional unit 72, and handoff functionality unit 78 is switched, so that output is from the output of relational calculus functional unit 63, the state that this state representation latch mode is cancelled or is disengaged.
According to these functions, as shown in figure 14, in low vehicle speeds, under the reverse state of the bearing circle that is diverted,, make bearing circle reverse easily by SAT and reverse auxiliary force are made up, and can eliminate risk intrinsic in conventional example, that is: bearing circle is not backwards to the straight ahead position but Halfway Stopping, makes like this to turn to sense to become sensitive and smooth-going, thereby can realize turning to the remarkable improvement of sense.
Below, will second embodiment according to the forwards/reverse state discrimination function unit of electric motor driven power steering system of the present invention be specifically described.In a second embodiment, different with reference in the first embodiment described forwards/reverse state discrimination function unit of predetermined value memory function unit 66, relational calculus functional unit 68, predetermined value memory function unit 74 and relational calculus functional unit 76, it is identical that other parts keep.Figure 15 is the block scheme that illustrates according to the formation of second embodiment of forwards/reverse state discrimination function of the present invention unit.Except predetermined value memory function unit 100, relational calculus functional unit 101, predetermined value memory function unit 102 and relational calculus functional unit 103, the same numeral that uses when with reference to Fig. 5 first embodiment being described is given to the identical component parts among Figure 15, and will omit the explanation to these identical component parts.
The speed of a motor vehicle of predetermined value memory function unit 100 storage 30km/h is as the 3rd predetermined value, and the 3rd predetermined value is outputed to the relational calculus functional unit.Relational calculus functional unit 101 compares the 3rd predetermined value of the speed of a motor vehicle and 30km/h, be equal to or less than in the speed of a motor vehicle under the situation of predetermined value of 30km/h, 101 outputs " 1 " of relational calculus functional unit, the speed of a motor vehicle greater than situation as the 30km/h of the 3rd predetermined value under, 101 outputs " 0 " of relational calculus functional unit.
102 storages of predetermined value memory function unit and output 30km/h are as the 3rd predetermined value.Relational calculus functional unit 103 the speed of a motor vehicle with compare as the 30km/h of the 3rd predetermined value, under the situation of the speed of a motor vehicle greater than 30km/h, 103 outputs " 1 " of relational calculus functional unit are equal to or less than in the speed of a motor vehicle under the situation of 30km/h, 103 outputs " 0 " of relational calculus functional unit.
Below, will the operation of second embodiment of forward/reverse state decision-making function unit be described.
Be in reverse state at bearing circle, motor speed (MSPD) is equal to or greater than desired speed A rps and the speed of a motor vehicle is equal to or less than under the condition of 30km/h, from 61 outputs " 1 " of sign determination functional unit, and from 62 outputs " 0 " of sign determination functional unit.As a result, from 63 outputs " 1 " of relational calculus functional unit.From 67 outputs " 1 " of relational calculus functional unit, and from 101 outputs " 1 " of relational calculus functional unit.As a result, from 69 outputs " 1 " of logic operation functional unit, and from 70 outputs " 1 " of logic operation functional unit.From 103 outputs " 0 " of relational calculus functional unit, and from 75 outputs " 0 " of relational calculus functional unit.As a result, from 77 outputs " 1 " of logic operation functional unit.Thus, from 72 outputs " 1 " of logic operation functional unit, and the output from logic operation functional unit 72 is output from handoff functionality unit 78 as the output from forwards/reverse state discrimination function unit, thereby keeps (latching) in reverse state judging.The figure center B of portion represents to be used to keep the processing of latching judged.
During arbitrary condition, latch mode is cancelled or is disengaged: the rotating speed of bearing circle equals or is slower than desired speed, that is: motor speed (MSPD) equals or is slower than desired speed BB rps, and the speed of a motor vehicle is equal to or greater than 30km/h below satisfying.Herein, the first predetermined value AA is the value greater than the second predetermined value BB.That is to say, from 61 outputs " 0 " of sign determination functional unit, and from 62 outputs " 0 " of sign determination functional unit.As a result, from 63 outputs " 0 " of relational calculus functional unit.From 67 outputs " 0 " of relational calculus functional unit, and from " 0 " of logic operation functional unit 69 outputs as logic product.From 101 outputs " 0 " of relational calculus functional unit, from 75 outputs " 1 " of relational calculus functional unit, from 103 outputs " 1 " of relational calculus functional unit, and owing to when before sampling, have latch mode, thereby preceding value memory function unit 71 is in " 1 ".Although from 70 outputs " 1 " of logic operation functional unit, yet from " 0 " of logic operation functional unit 77 outputs as nondisjunction, and from 72 outputs " 0 " of logic operation functional unit, handoff functionality unit 78 is switched, so that output is from the output of relational calculus functional unit 63.As a result, the forward condition signal is output.
Under the condition beyond the condition that reverse state is latched, that is: under the condition of logic operation functional unit 72 outputs " 0 ", output from relational calculus functional unit 63 is output as the output from forwards/reverse state discrimination function unit, and it is the same with conventional determination processing, the direction of bearing circle is decided by the direction (symbol) of steering torque and the direction (symbol) of motor speed, under the identical situation of symbol, the expression direction, and under the different situation of symbol, expression inverse direction (the figure center D of portion).
According to these functions, in low vehicle speeds, under the reverse state of the bearing circle that is diverted, by SAT and reverse auxiliary force are made up, make bearing circle reverse easily, and can eliminate risk intrinsic in conventional example, that is: bearing circle is not backwards to the straight ahead position but Halfway Stopping, make like this to turn to sense to become sensitive and smooth-going, thereby can realize turning to the remarkable improvement of sense.
In addition, under following situation, that is: motor speed is equal to or greater than after the first predetermined value AA in reverse state, bearing circle is reversed rotation so that become under the situation of the forward condition on the relative direction, motor speed does not become and is equal to or less than second predetermined value, and the reverse state that latchs is not removed.Yet this moment, be input to the moment of torsion that bearing circle and value are equal to or greater than described predetermined value owing to produce immediately, thereby oppositely auxiliary torque compares vanishing, and owing to multiply by in the determining of reverse damping compensation current signal is zero reverse auxiliary torque ratio, as its result, oppositely damping compensation current signal vanishing, thus in the case also can smooth-going direction of operating dish.
As seen from the above description, according to the present invention, provide following advantage.
Be in reverse state owing to being judged to be by forwards/reverse state discrimination function unit at steering system Afterwards, forwards/reverse state discrimination function unit continues to keep reverse state, until turned to by motor Speed measuring ability unit inspection to the absolute value of motor speed be down to predetermined value or following, thereby By adopting a kind of steering angle sensor of costliness that do not use to use steering torque and motor speed The formation of data, even when the vehicle low speed rotation is reverse to middle steering wheel, steering torque crosses over zero, In order to be in this condition in its sign modification one-tenth relation consistent with the symbol of motor speed Lower, forwards/reverse state discrimination function unit does not judge at once that also the state of steering wheel is in the forward shape Attitude, but the judgement that continues to keep reverse state until satisfy certain condition, like this, is worked as vehicle When running at a low speed, in the steering wheel reverse operating, steering wheel can almost be backwards to the straight ahead position And Halfway Stopping not turns to sense thereby significantly improve.
Be in reverse state owing to being judged to be by forwards/reverse state discrimination function unit at steering system Afterwards, forwards/reverse state discrimination function unit continues to keep reverse state, until by speed of a motor vehicle sensing The speed of a motor vehicle that device detects is down to predetermined value or following, thereby by adopting a kind of expensive turning to of not using Use the formation of steering torque and motor speed data to angle transducer, though when vehicle low When steering wheel was reverse during speed turned to, steering torque crossed over zero, in order to be in its sign modification Cheng Yudian Under this condition in the consistent relation of the symbol of engine speed, forwards/reverse state discrimination function list The state that unit also is not judged to be steering wheel at once is in forward condition, but continues to keep reverse state Judgement, until satisfy certain condition, like this, when low vehicle speeds, reverse at steering wheel In the operation, steering wheel can almost be backwards to the straight ahead position and non-Halfway Stopping, and along with car Speed increases, and locking is disengaged, and turns to sense thereby significantly improve.
Claims (2)
1. electric motor driven power steering system, it comprises:
Steering torque sensor is used for the steering torque of vehicle steering system is detected;
Car speed sensor is used for car speed is detected;
Electrical motor is used for turning to auxiliary torque additional to steering system;
Motor speed computing function unit is used for motor speed is calculated; And
Motor controller be used at least according to setting the target current value that is used to be transmitted to electrical motor by the detected steering torque of steering torque sensor, and output is used for the control signal of driving motor;
Motor controller comprises:
Forwards/reverse state discrimination function unit is used for according to the positive and negative of steering torque and motor speed the forward condition or the reverse state of steering system being judged; And
Arithmetic and logic unit, be used under the situation of reverse state, based on from the signal of the output signal of motor speed computing function unit with based on signal plus from the output signal of steering torque sensor, thereby oppositely control according to output signal from this arithmetic and logic unit, wherein
Steering system be judged to be by forwards/reverse state discrimination function unit be in reverse state after, forwards/reverse state discrimination function unit continues to keep reverse state, reduces to predetermined value or following up to the absolute value of the motor speed that is calculated by motor speed computing function unit.
2. electric motor driven power steering system, it comprises:
Steering torque sensor is used for the steering torque of vehicle steering system is detected;
Car speed sensor is used for car speed is detected;
Electrical motor is used for turning to auxiliary torque additional to steering system;
Motor speed computing function unit is used for motor speed is calculated; And
Motor controller be used at least according to setting the target current value that is used to be transmitted to electrical motor by the detected steering torque of steering torque sensor, and output is used for the control signal of driving motor;
Motor controller comprises:
Forwards/reverse state discrimination function unit is used for according to the positive and negative of steering torque and motor speed the forward condition or the reverse state of steering system being judged; And
Arithmetic and logic unit, be used under the situation of reverse state, based on from the signal of the output signal of motor speed computing function unit with based on signal plus from the output signal of steering torque sensor, thereby oppositely control according to output signal from this arithmetic and logic unit, wherein
Steering system be judged to be by forwards/reverse state discrimination function unit be in reverse state after, forwards/reverse state discrimination function unit continue to keep reverse state, up to reducing to predetermined value or following by the detected speed of a motor vehicle of car speed sensor.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002351382A JP3895675B2 (en) | 2002-12-03 | 2002-12-03 | Electric power steering device |
| JP351382/2002 | 2002-12-03 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1504372A CN1504372A (en) | 2004-06-16 |
| CN100408405C true CN100408405C (en) | 2008-08-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2003101170815A Expired - Fee Related CN100408405C (en) | 2002-12-03 | 2003-12-03 | Electric power steering system |
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| Country | Link |
|---|---|
| JP (1) | JP3895675B2 (en) |
| CN (1) | CN100408405C (en) |
| BR (1) | BRPI0305453B1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010074915A (en) * | 2008-09-17 | 2010-04-02 | Jtekt Corp | Motor controller and electric power steering device |
| PL2402234T3 (en) * | 2010-07-01 | 2014-04-30 | Steering Solutions Ip Holding | Dynamic system compensator for actively controlled power steering systems |
| US9254862B2 (en) * | 2011-05-25 | 2016-02-09 | Mitsubishi Electric Corporation | Electric power steering control device |
| KR101767878B1 (en) * | 2011-07-22 | 2017-08-30 | 현대모비스 주식회사 | Steering control device of motor driven powersteering system |
| CN104326016B (en) * | 2014-10-31 | 2017-01-18 | 江苏富尔达机械有限公司 | Anti-rotation double detection system of vehicle electric power steering system |
| JP7056362B2 (en) * | 2018-05-10 | 2022-04-19 | オムロン株式会社 | Motor control device and programming device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6102151A (en) * | 1997-07-24 | 2000-08-15 | Honda Giken Kogyo Kabushiki Kaisha | Electric power steering apparatus |
| US6148949A (en) * | 1997-08-27 | 2000-11-21 | Honda Giken Kogyo Kabushiki Kaisha | Electric power steering apparatus |
| JP2001247049A (en) * | 2000-03-06 | 2001-09-11 | Koyo Seiko Co Ltd | Electric power steering device |
| DE10031215A1 (en) * | 2000-03-29 | 2001-10-11 | Mitsubishi Electric Corp | Controller for electrical power steering has torque sensor, auxiliary steering force motor and control unit that controls or regulates motor in response to steering torque information |
-
2002
- 2002-12-03 JP JP2002351382A patent/JP3895675B2/en not_active Expired - Fee Related
-
2003
- 2003-12-02 BR BRPI0305453A patent/BRPI0305453B1/en not_active IP Right Cessation
- 2003-12-03 CN CNB2003101170815A patent/CN100408405C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6102151A (en) * | 1997-07-24 | 2000-08-15 | Honda Giken Kogyo Kabushiki Kaisha | Electric power steering apparatus |
| US6148949A (en) * | 1997-08-27 | 2000-11-21 | Honda Giken Kogyo Kabushiki Kaisha | Electric power steering apparatus |
| JP2001247049A (en) * | 2000-03-06 | 2001-09-11 | Koyo Seiko Co Ltd | Electric power steering device |
| DE10031215A1 (en) * | 2000-03-29 | 2001-10-11 | Mitsubishi Electric Corp | Controller for electrical power steering has torque sensor, auxiliary steering force motor and control unit that controls or regulates motor in response to steering torque information |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2004182078A (en) | 2004-07-02 |
| BRPI0305453B1 (en) | 2016-02-23 |
| JP3895675B2 (en) | 2007-03-22 |
| BR0305453A (en) | 2004-08-31 |
| CN1504372A (en) | 2004-06-16 |
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