Technical field
[0001]
　The present invention relates to an electric power steering apparatus for applying a steering assist force by the motor to a steering system of a vehicle, to reduce the discomfort caused by noise during low-speed steering in particular, a smooth steering as no phase lag at the time of high-speed steering to the motor angular cutoff frequency of the filter unit, or by allowing the variable in the motor angular velocity and the vehicle speed, to high-performance electric power steering apparatus minute vibration is improved less steering feeling.
Background technique
[0002]
　Steering assist force and the steering system in the rotational force of the motor vehicle electric power steering apparatus which provides (assist force) (EPS) is the driving force of the motor by the transmission mechanism such as gears or a belt via reduction gear, a steering shaft or adapted to impart a steering assist force to the rack shaft. Such conventional electric power steering apparatus, in order to accurately generate a torque of the steering assist force, and performs a feedback control of a motor current. The feedback control is the difference between the steering assist command value (current command value) and the motor current detection value to adjust the voltage applied to the motor so as to reduce, adjustment of the voltage applied to the motor, generally PWM control du - is carried out by adjusting the tee.
[0003]
　To describe the general construction of an electric power steering apparatus shown in FIG. 1, column shaft of the handle 1 (steering shaft, the steering wheel shaft) 2 is a reduction gear 3, universal joints 4a and 4b, a pinion rack mechanism 5, tie rods 6a, through 6b, it is connected further hub unit 7a, via 7b steering wheels 8L, the 8R. In addition, the column shaft 2, a torque sensor 10 for detecting the steering torque of the steering wheel 1 is provided, the motor 20 for assisting the steering force of the steering wheel 1 is connected to the column shaft 2 through the reduction gear 3 . The control unit (ECU) 30 for controlling the electric power steering apparatus, the electric power from the battery 13 is supplied, the ignition key signal is inputted through the ignition key 11. Control unit 30, based on the vehicle speed Vel detected by the steering torque Th and the vehicle speed sensor 12 detected by the torque sensor 10, performs a computation of the current command value of the assist command, compensation for the computed current command value controlling the current supplied to the motor 20 by the voltage control value Vref subjected to. Steering angle sensor 14 is not mandatory and may not be disposed, may be obtained from the rotation sensor such as a resolver connected to the motor 20.
[0004]
　The control unit 30 is connected with a CAN (Controller Area Network) 40 for exchanging various kinds of information of the vehicle, the vehicle speed Vel is also possible to receive from CAN40. Further, the control unit 30, communications other than CAN40, an analog / digital signal, even non CAN41 for exchanging radio waves connectable.
[0005]
　In such an electric power steering device, it is constituted by the control unit 30 mainly CPU (including MPU or MCU), when illustrating the general functions performed by the program in the CPU, for example, shown in FIG. 2 It has become such a configuration is.
[0006]
　To explain the function and operation of the control unit 30 with reference to FIG. 2, the vehicle speed Vel from the steering torque Th and the vehicle speed sensor 12 from the torque sensor 10, the calculated current command value by using the assist map or the like compensation for is input to the torque controller 31 to be applied, the current command value Iref1 calculated by the torque control unit 31 is limited to a maximum value at the current limiting unit 33, the maximum value the current command value is limited to Irefm is the subtraction unit 32B is inputted, it is subtracted and the motor current detection value Im.
[0007]
　A subtraction result of the subtraction unit 32B deviation I (= Irefm-Im) is inputted to the current controller 35 for controlling the PI control or the like, the voltage control value Vref which is a current control is inputted to the PWM control unit 36, It is calculated the duty in synchronization with the carrier signal CF, to PWM drive the motor 20 via the inverter 37 with the PWM signal. Motor current value Im of the motor 20 is detected by a motor current detector 38, is inputted to the subtraction unit 32B by feedback.
[0008]
　The motor 20 is connected a rotation sensor 21 such as a resolver is motor angle θ is output from the rotation sensor 21.
[0009]
　In such an electric power steering apparatus, minute vibrations are generated at the time or slow steering wheel steering holding, which may cause discomfort to the driver. Be mentioned as one of the causes is the high frequency noise of the motor angular acceleration signal.
[0010]
　For such high-frequency noise, as compensator which utilizes a motor angular acceleration, by performing signal processing of the road surface information and disturbance in a high frequency range, and easy to tune, the aim of suppression of the brake judder and shimmy, safety in a comfortable steering performance electric power steering device obtained it has been proposed as Japanese Patent No. No. 4,715,212 (Patent Document 1).
[0011]
　In the electric power steering apparatus of Patent Document 1, the motor rotation angular velocity, the motor rotation angular acceleration, the SAT feedback section for estimating the steering assist force and a steering signal to input self-aligning torque (SAT) is provided, obtained SAT values, as well as added to the steering assist command value through the transfer function section and gain section comprises a high-pass filter, and the characteristics of the high-pass filter and the gain section is changed by responding to the vehicle speed signal.
CITATION
Patent Document
[0012]
Patent Document 1: Japanese Patent No. 4715212
Summary of the Invention
Problems that the Invention is to Solve
[0013]
　In the apparatus described in Patent Document 1 has changed the cutoff frequency by the vehicle speed, type of filter is a high-pass filter (HPF). The purpose of the high pass filter suppressing the judder and shimmy is the main, but to increase the responsiveness of the high-frequency side. Therefore, with respect to the minute vibration of the steering hold or in a low speed steering when due to high frequency noise of the angular acceleration, it is assumed ineffective. Moreover, applying a filter to the motor angular acceleration signal and to remove noise collectively, delays during high-speed steering will be (deviation large due to the phase lag) occurs, because thus degrade the performance of the compensator, steering it is inferred that feeling is deteriorated.
[0014]
　The present invention has been made in view of the above described circumstances, an object of the present invention is to reduce the discomfort caused by noise at the time or in a low speed steering steering holding, at the time of high-speed steerable smooth steering as no phase delay It is to provide an electric power steering apparatus.
Means for Solving the Problems
[0015]
　The present invention, at least has a torque control unit for calculating a current command value based on the steering torque, and drives the motor by a current control system based on the current command value, so as to assist control and the steering system It relates to an electric power steering apparatus, the object of the present invention, a motor angular velocity calculator for calculating a motor angular velocity omega of the motor rotation angle, and the motor angular acceleration calculator for calculating a motor angular acceleration α from the motor angular velocity omega, the motor ; and a stability compensation unit for calculating a compensation steering torque and the compensation current command value on the basis of the angular velocity ω and the motor angular acceleration alpha, compensates the steering torque by the compensation steering torque, the compensating current It is accomplished by compensating the current command value in the command value.
[0016]
The above-described object of the present invention, the stability compensation unit, and a first cut-off frequency controller for setting a cut-off frequency fc1 on the basis of the motor angular velocity omega, the motor in accordance with the cut-off frequency fc1 a first filter unit for filtering the angular acceleration alpha, a second cutoff frequency controller for setting a cut-off frequency fc2 on the basis of the motor angular velocity omega, the motor angular acceleration in response to the cut-off frequency fc2 by being composed of a second filter unit for filtering the alpha, or the first variable cutoff frequency section, the cut-off frequency fc1 constant at motor angular speed ω1 below, the motor angular speed ω1 a cut-off frequency characteristic higher linear or non-linear in more than area, the second cutoff frequency Variable portion, by which the cut-off frequency fc2 is constant at a motor angular speed ω2 (> ω1) below, a higher becomes the cut-off frequency characteristics linearly or non-linear in region exceeding the motor angular velocity .omega.2, or the first variable cutoff frequency of 1, the cut-off frequency fc1 is increased linearly with the motor angular speed .OMEGA.10 below a becomes higher cut-off frequency characteristics linearly or non-linear in region exceeding the motor angular velocity .OMEGA.10, the second the cut-off frequency controller has a cutoff frequency characteristic that the motor angular velocity ω11 (> ω10) the cut-off frequency fc2 by the following increases linearly increases linearly or non-linear in region exceeding the motor angular velocity .OMEGA.11 the or more cars for the calculation of the compensation steering torque and the compensating current command value Vel is used, and by the used respectively the motor angular speed ω and the vehicle speed Vel to set the cut-off frequency fc1 and fc2, or the first variable cutoff frequency section, and the motor angular velocity ω a frequency fc11 determined by the angular velocity corresponding map showing a relationship between a frequency and an arithmetic mean of the frequency fcv11 determined by the vehicle speed corresponding map showing the relationship between the vehicle speed Vel and frequency Has become a frequency such that said cut-off frequency fc1, the second cutoff frequency controller is a frequency fc21 determined by the angular velocity corresponding map showing the relation between the motor angular velocity ω and the frequency, vehicle speed by has a frequency arithmetic mean and frequency fcv21 determined by the vehicle speed corresponding map showing the relationship between the Vel and frequency such that the cut-off frequency fc2, or the first cutoff frequency controller angular velocity corresponding map, the frequency fc11 constant at motor angular Omega21 below, the a higher becomes the frequency characteristic linear or non-linear in region exceeding the motor angular Omega21, angular correspondence map of the second cut-off frequency controller but the frequency fc21 constant at the motor angular velocity ω22 (> ω21) below, wherein By has a higher becomes the frequency characteristic linear or non-linear in region exceeding the motor angular velocity Omega22, or the first cutoff angular correspondence map frequency controller is increased the frequency fc11 is linearly by the motor angular velocity ω21 less and, wherein a higher becomes the frequency characteristic linear or non-linear in region exceeding motor angular velocity Omega21, the second cut-off angular correspondence map frequency controller is the motor angular velocity ω22 (> ω21) said frequency fc21 below linear increase, by which a higher becomes the frequency characteristic linear or non-linear in region exceeding the motor angular velocity Omega22, or the first cutoff speed correspondence map frequency controller is slow speed of the vehicle speed Vel to It holds a constant value fcv11 in Vel11 below the slow speed Vel11 super , Frequency linear or non-linear at high speed in the vehicle speed Vel12 following fcv12 reduced to ( ω31) or less, linear in a region exceeding the motor angular velocity Omega32 or by that a higher becomes the frequency characteristic to the nonlinear, or the first cutoff angular correspondence map frequency controller is the frequency fc31 increases linearly with the motor angular velocity ω31 below, exceeds the motor angular velocity ω31 a higher becomes the frequency characteristic linear or non-linear in the region, the 2 cutoff angular correspondence map frequency controller is the frequency fc32 increases linearly with the motor angular velocity ω32 (> ω31) hereinafter become higher becomes the frequency characteristic linear or non-linear in region exceeding the motor angular velocity Omega32 by there, or the first cutoff speed corresponding map of the frequency variable unit, said hold the constant value fcv31 on slow speed Vel vehicle speed Vel31 below, beyond the slow speed Vel31, fast
Effect of the Invention
[0017]
　According to the electric power steering apparatus of the present invention, the stability compensator, by setting the lower cut-off frequency at the time and slow steering steering holding is set to be higher cut-off frequency at the time of high-speed steering, the motor angular velocity it is possible to suppress the noise component, without compromising the performance of the compensator in the high frequency region, less steering feeling of the micro vibration caused by the motor angular acceleration noise at the time or in a low speed steering steering holding is obtained.
[0018]
Further, since the filtering characteristic of the stability compensation unit is divided into the compensation of the compensating current command value of the steering torque can be given an effective compensation values. Thus, it included in the steering torque, a reduction gear to remove the torque ripple caused by the steering mechanism system or the torque sensor including, can generate an ideal torque command value by extracting only the steering torque of the driver. On the other hand, in the compensation current command value, including the variation and the cogging torque of the individual motors, and the torque ripple generated by electrical factors, since the compensation for reducing floor vibration, small vibration does not easily occur.
[0019]
　Furthermore, by varying the cut-off frequency in accordance with the vehicle speed, it is possible to achieve both reducing vibration and steering feeling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020]
Is a block diagram showing an outline of FIG. 1 the electric power steering system.
Is a block diagram showing a configuration example of a control system of FIG. 2 the electric power steering apparatus.
3 is a block diagram illustrating a configuration example (first embodiment) of the present invention.
4 is a block diagram showing a configuration example of a stabilization compensating portion (first embodiment).
5 is a characteristic diagram showing a characteristic example of a cut-off frequency (motor angular velocity) of the first embodiment.
6 is a flowchart showing an operation example (first embodiment) of the present invention.
7 is a block diagram showing a configuration example of the present invention (second embodiment).
8 is a block diagram showing a configuration example of a stability compensation section (second embodiment).
9 is a characteristic diagram showing a characteristic example of a cut-off frequency of the second embodiment (motor angular velocity).
FIG. 10 is a characteristic diagram showing a characteristic example of a cut-off frequency (speed) of the second embodiment.
11 is a flowchart showing an operation example (second embodiment) of the present invention.
12 is a characteristic diagram showing a characteristic example of a cut-off frequency of the third embodiment (motor angular velocity).
13 is a characteristic diagram showing a characteristic example of a cut-off frequency (speed) of the third embodiment.
14 is a flowchart showing an operation example (third embodiment) of the present invention.
15 is a characteristic diagram showing another example of the characteristic of the cutoff frequency (motor angular velocity).
DESCRIPTION OF THE INVENTION
[0021]
　In the electric power steering apparatus of the present invention, the motor angular velocity and motor angular acceleration, or the motor angular velocity 及 by stability compensator based on motor angular acceleration and the vehicle speed, at the time of low speed steering reduces discomfort due to noise, the phase delay at the time of high-speed steering to smooth steering as not, the cutoff frequency of the filter unit for filtering process a motor angular acceleration, and to be variable in accordance with the motor angular velocity or motor angular velocity and the vehicle speed. That is, to set the low cut-off frequency at the time and slow steering the steering holding, set to be higher cut-off frequency at the time of high-speed steering, which achieved good electric power steering apparatus with small vibration is small steering feeling.
[0022]
　Hereinafter, an embodiment of the present invention with reference to the drawings.
[0023]
　Figure 3 shows an example of the present invention embodiment (first embodiment) in correspondence with FIG. 2, the motor angle θ from the rotation sensor 21 connected to the motor 20 are input to the motor angular velocity calculation unit 100 , the motor angular velocity ω is calculated (differential). The motor angular velocity ω is inputted into the motor angular acceleration calculation unit 101 and the stability compensation unit 110, stability compensation unit 110 generates a variable controlled and compensated steering torque Tf and the compensation current command value If the cut-off frequency. Further, the input side of the torque control unit 31 is provided with subtractor unit 34A, the adding unit 34B is provided between the torque control section 31 and the current limiting unit 33. The subtraction unit 34A is the steering torque Th are added input, the compensation steering torque Tf is subtracted input, the adding unit 34B in the current command value Iref1 and the compensation current command value If is added.
[0024]
　Stability compensation unit 110 as shown in FIG. 4, the cut-off frequency (fc) variable 111 and 112 for varying the cutoff frequency fc based on the motor angular velocity omega, the cutoff frequency of the cutoff frequency controller 111 based on fc1, a filter unit 113 for filtering the motor angular acceleration alpha, based on the cut-off frequency fc2 of the cutoff frequency controller 112, a filter 114 for filtering the motor angular acceleration alpha, filter unit 113 and compensation steering torque generator 115 for outputting a compensation steering torque Tf on the basis of the output from, the compensating current command value generation unit 116 for outputting a compensation current command value If on the basis of the output from the filter section 114 in is configured.
[0025]
　As the characteristics of the cut-off frequency controller 111 shown in FIG. 5, for example, a certain cut-off frequency fc1 to the motor angular velocity .omega.1, and has a characteristic to increase the cut-off frequency fc linearly by the motor angular speed .omega.1 larger area . Similarly, the cut characteristics of the off-frequency controller 112 as shown in FIG. 5, for example, a motor angular speed ω2 (> ω1) until a certain cut-off frequency fc2 (> fc1), the cutoff frequency in the motor angular velocity .omega.2 larger area and it has a characteristic to increase the fc linearly.
[0026]
　In such a configuration, it will be described operation example (first embodiment) with reference to the flowchart of FIG.
[0027]
　First detected motor angle θ is the rotation sensor 21 (step S1), the motor angle θ is motor angular speed ω is calculated is input to the motor angular velocity calculation unit 100 (step S2). The motor angular velocity omega (step S3) together with the motor angular acceleration α is calculated is input to the motor angular acceleration calculation unit 101, it is inputted to the cut-off frequency varying unit 111 and 112 of the stability compensation unit 110. Motor angular acceleration α is input to the filter section 113 and 114 of the stability compensation unit 110.
[0028]
　First, in accordance with the characteristics shown in FIG. 5, the cutoff frequency controller 111 to vary the cut-off frequency fc1 (step S4). Cut-off frequency fc1 that is set is input to the filter unit 113, the motor angular acceleration α is filtering processing in accordance with the cut-off frequency fc1 by the filter unit 113 (step S5). Filtered signal processed by the filter 113 is input to the compensation steering torque generator 115, the signal processed compensated steering torque Tf is inputted to the subtraction unit 34A by the compensation steering torque generator 115, the steering torque Th is is compensated (step S6).
[0029]
　Thereafter, in accordance with the characteristics shown in FIG. 5, the cutoff frequency controller 112 to vary the cut-off frequency fc2 (step S10). Cut-off frequency fc2 that is set is input to the filter unit 114, the motor angular acceleration α is filtering processing in accordance with the cut-off frequency fc2 by the filter unit 114 (step S11). Filtered signal processed by the filter unit 114 is inputted to the compensating current command value generation section 116, the signal processed compensated current command value If is input to the adder 34B in the compensation current command value generation section 116, current command value Iref is compensated (step S12).
[0030]
　The above operation is repeated until the end (step S13).
[0031]
　Thus, the cutoff frequency fc1 and fc2 of the filter unit 113 and 114 to allow the variable in the motor angular velocity omega, set the low cut-off frequency at the time and slow steering steering holding, the higher the cut-off frequency at the time of high-speed steering since the set as, without deteriorating the characteristics of the high-frequency side, it is possible to suppress the vibration becomes a problem in a low frequency side (steering holding micro vibration). That is, by effectively removing noise on the motor angular acceleration, thereby improving the performance of the compensator. Thus, the steering feeling good electric power steering device is obtained.
[0032]
　Figure 7 shows a second embodiment of the present invention in association with FIG. 3, further vehicle speed Vel in the second embodiment is inputted to the stability compensator 110A. Structure stability compensator 110A, as shown in FIG. 8, and the cut-off frequency (fc) variable region 111A and 112A for varying the cutoff frequency fc based on the motor angular speed ω and the vehicle speed Vel, the cut-off frequency varying unit 111A based on the cut-off frequency fc1 of the filter unit 114 and the filter unit 113 for filtering the motor angular acceleration alpha, based on the cut-off frequency fc2 of the cut-off frequency varying unit 112A, for filtering the motor angular acceleration alpha When, and compensation steering torque generator 115 for outputting a compensation steering torque Tf on the basis of the output from the filter section 113, compensation current command based on the output from the filter section 114 outputs the compensation current command value If It is composed of a value generation unit 116.
[0033]
　Characteristics of the cutoff frequency controller 111A, for example, as shown in FIG. 9, the constant cut-off frequency fc11 until the motor angular velocity Omega21, become characteristic to increase the cut-off frequency fc linearly motor angular velocity Omega21 larger area there. Similarly, the cut-off characteristics of the frequency controller 112A, for example, as shown in FIG. 9, and a motor angular velocity ω22 (> ω21) fixed cutoff frequency to fc21 (> fc11), cut-off motor angular Omega22 larger area It has a characteristic of increasing the frequency fc linearly.
[0034]
　Further, the cut characteristics of the off-frequency controller 111A, as shown in FIG. 10, for example, holds a constant value fcv11 on slow speed Vel vehicle speed Vel11 below, beyond the slow speed Vel11, linear or fast speed Vel12 below It decreased to frequency fcv12 (, beyond the slow speed Vel21 , reduced to the frequency fcv22 ( Vel12) below, and has a characteristic that holds the frequency Fcv22 in region exceeding fast speed Vel22. Cutoff frequency fcv12 and fcv22 may be zero.
[0035]
　For speed, slow speed Vel11 and Vel21, for example in particular a floor vibration or during slight vibration of about 0 ~ 2Km / h in question creep of the handle, extremely low speed running less than 5 Km / h in parking or when a garage or stopped state, even assumes a low speed up to about 30 Km / h for slow speed and urban and narrow roads, fast speed Vel12 and Vel22, for example wide 50Km in roads and highways / h ~ 80Km / h the extent traveling and of, assumes the running condition of the vehicle speed in excess of 80Km / h in the high-speed roads and motorways.
[0036]
　For the filter 113 and 114 to filtering the motor angular acceleration α according to the motor angular speed ω and the vehicle speed Vel is configured separately and compensation steering torque generator 115 by the compensation current command value generation section 116, which is different purpose to use a motor angular acceleration by the torque control unit 31 and the current control unit 35, characteristics of the motor angular acceleration is required due to differences individually. That is, the current control unit 35, but to compensate for the current command value in order to reduce the torque ripple and the floor vibration, the torque control unit 31, in order to extract only the steering information of the driver, the vibration component such as torque ripple It is removed from the torque sensor value. The torque sensor value, for detecting via column shaft and a reduction gear, the torsion bar, compared to the motor angular acceleration, vibration components included in low frequency band, the phase is delayed with respect to actual behavior. Thus, using the value of the same characteristics as the motor angular acceleration is used to compensate for the current command value, since the frequency band and the phase included do not match, not only the removal of the vibration component becomes insufficient, vibration there is a possibility that the addition of ingredients which cause the generation. Therefore, it is possible to effectively filtering by setting the cut-off frequency individually. Further, the cutoff frequency of the motor angular acceleration used for the torque control unit may be set to the same value or less than the cut-off frequency of the motor angular acceleration used for current control.
[0037]
　Furthermore, the characteristics of the cut-off frequency controller 111A and 112A includes a frequency determined in accordance with the motor angular velocity omega, it may be calculated by the arithmetic mean of the frequency determined in accordance with the vehicle speed Vel. Thus, for the micro-vibration of the floor vibration and handle the problem in the slow speed, by setting a low cutoff frequency in comparison with the high speed of the vehicle speed, it is possible to enhance the effect of suppressing vibration. On the other hand, in the high speed of the vehicle speed, since it can impact the steering feeling even a slight phase delay caused by the filtering process, the cut-off frequency is preferably set higher than the band of the torque controller. Since the high speed of the vehicle speed oscillation becomes slower problem will astray in road noise and the like, not be set high cut-off frequency problems.
[0038]
　On the other hand, when the steering speed even slower vehicle speed is fast, like the state of the fast speed, for a delay of the slight phase affects the steering feeling when steering speed is high, the cut-off frequency high it is necessary to set. Therefore, steering speed, that is, the cutoff frequency set by the motor angular speed by arithmetic mean cutoff frequency set by the vehicle speed, regardless of the steering state, effectively motor angular acceleration having optimum properties it can be calculated to.
[0039]
　In such a configuration, it will be described the operation example (second embodiment) with reference to the flowchart of FIG. 11.
[0040]
　First detected motor angle θ is the rotation sensor 21 (step S20), the motor angle θ is motor angular speed ω is calculated is input to the motor angular velocity calculation unit 100 (step S21). The motor angular velocity ω motor angular acceleration α is input to a motor angular acceleration calculation unit 101 is calculated (step S22), and the vehicle speed Vel is inputted (step S23). Motor angular speed ω and the vehicle speed Vel is inputted to the cut-off frequency varying unit 111A and 112A of the stability compensation section 110A, the motor angular acceleration α is input to the filter section 113 and 114 of the stability compensation unit 110. The input order of the vehicle speed Vel can be appropriately changed.
[0041]
　Then, the frequency determined according to the motor angular velocity ω according to the characteristics shown in FIGS. 9 and 10, the arithmetic mean of the frequency determined in accordance with the vehicle speed Vel, the cut-off frequency variable unit 111A is cut-off frequency fc1 variable (step S24). Cut-off frequency fc1 that is set is input to the filter unit 113, the motor angular acceleration α is filtering processing in accordance with the cut-off frequency fc1 by the filter unit 113 (step S25). Filtered signal processed by the filter 113 is input to the compensation steering torque generator 115, the signal processed compensated steering torque Tf is inputted to the subtraction unit 34A by the compensation steering torque generator 115, the steering torque Th is It is compensated (step S26).
[0042]
　Then, variable frequency determined in accordance with the motor angular velocity ω according to the characteristics shown in FIGS. 9 and 10, the arithmetic mean of the frequency determined in accordance with the vehicle speed Vel, the cut-off frequency varying unit 112A is the cut-off frequency fc2 (step S30). Cut-off frequency fc2 that is set is input to the filter unit 114, the motor angular acceleration α is filtering processing in accordance with the cut-off frequency fc2 by the filter unit 114 (step S31). Filtered signal processed by the filter unit 114 is inputted to the compensating current command value generation section 116, the signal processed compensated current command value If is input to the adder 34B in the compensation current command value generation section 116, current command value Iref is compensated (step S32).
[0043]
　The above operation is repeated until the end (step S33).
[0044]
　Thus, the cutoff frequency fc1 and fc2 of the filter unit 113 and 114 to allow the variable in the motor angular velocity ω and the vehicle speed Vel, set the low cut-off frequency at the time and slow steering steering holding, the cutoff frequency at the time of high-speed steering since the set to become higher without deteriorating the characteristics of the high-frequency side, it is possible to suppress the vibration becomes a problem in a low frequency side (steering holding micro vibration). That is, by effectively removing noise on the motor angular acceleration, thereby improving the performance of the compensator. Thus, the steering feeling good electric power steering device is obtained.
[0045]
　Cut-off frequency (fc) variable region 111A and 112A are good even characteristics shown in FIGS. 12 and 13 (third embodiment). Configuration of the third embodiment is 7 and 8, is similar to the second embodiment. That is, the characteristics of the cut-off frequency variable unit 111A, as shown in FIG. 12, a certain cut-off frequency fc31 until the motor angular velocity Omega31, become characteristic to increase the cut-off frequency fc linearly motor angular velocity Omega31 larger area there. Similarly, the characteristics of the cut-off frequency variable unit 112A, as shown in FIG. 12, the motor angular velocity ω32 (> ω31) until a constant cutoff frequency fc32 (> FC31), the cutoff frequency fc in the motor angular velocity Omega32 larger area and it has a characteristic to increase linearly with.
[0046]
　Further, the cut-off characteristic of the frequency variable unit 111A, as shown in FIG. 13, holds a constant value fcv41 in the vehicle speed Vel41 following slow speed Vel, beyond the slow speed Vel41, linear or non-linear at high speed in the vehicle speed Vel42 below in increases to the frequency fcv42 (> fcv41), it has a characteristic that holds the frequency Fcv42 in region exceeding fast speed Vel42. Similarly, the characteristics of the cut-off frequency variable unit 112A, as shown in FIG. 13, to maintain a constant value fcv31 (> fcv41) following slow speed of the vehicle speed Vel Vel31 (> Vel41), beyond the slow speed Vel31, increased to the frequency fcv32 (> fcv31) with linear or non-linear at high speed of the vehicle speed Vel32 below, it has a characteristic that holds the frequency fcv32 in region exceeding fast speed Vel32. Cutoff frequency fcv41 and fcv31 may be zero.
[0047]
　For vehicle speed Vel, slow speed Vel41 and Vel31, for example especially an electric power floor vibration or during slight vibration of about 0 ~ 2km / h in question creep handle a steering device and a vibration source, during parking or garage extremely low speed running or stopped state less than 5km / h when further is assumed to slow the travel of up to about 30 km / h for slow speed and urban and narrow roads, fast speed Vel42 and Vel32, for example wide road and running or about 50km / h ~ 80km / h in the highway, it is assumed running condition at a vehicle speed exceeding 80 km / h in highways and motorways.
[0048]
　Further, even slow speed, when the steering speed is high, since the delay in the fast speed of the state as well as slight phase affects the steering feeling, it is desirable to increase the cut-off frequency. If the vehicle speed Vel is motor angular velocity ω is higher in a low state, i.e. several times when steering at a high steering speed during traveling at a low speed of the vehicle speed, for example a weighted constant W1 10, W2 to as 1 W1 and W2 is set to to several tens of times, by set higher than the frequency determined in accordance with the cut-off frequency to the vehicle speed Vel, it can remove noise without impairing the steering feel. Thus, calculating the cut-off frequency set by the motor angular velocity omega, by performing weighted averaging of the cut-off frequency set by the vehicle speed Vel, the motor angular acceleration α having optimum properties efficiently regardless of the steering state can do.
[0049]
　Vibration characteristics and the steering performance may vary depending on the type and the state of the vehicle, in particular and variations of the finished vehicle, the use of the vehicle state, in order to respond to changes in characteristics due to aging, the weighted average of the weighting constants W1 and W2 the by tuning in accordance with the state of the vehicle, it is possible to realize a more effective fine vibration characteristics and steering performance. For example, in such a derived vehicle based vehicle, the frequency if the frequency of floor vibration is increased by improvement of the vehicle component, the weighting constants W1 of frequency determined according to the motor angular velocity omega, was determined in accordance with the vehicle speed Vel by greater than the weighted constant W2, it is possible to raise the sensitivity for motor angular velocity ω improve steering performance. In more setting one of the weighting constants to zero, the cutoff frequency motor angular velocity ω alone, or it is possible to variably only by the vehicle speed Vel, according to the actual vibration characteristics and steering performance of the vehicle required filter unit About 113 and 14, it is possible to set the properties of the different cut-off frequencies.
[0050]
　In such a configuration, it will be described operation example (third embodiment) with reference to the flowchart of FIG. 14.
[0051]
　First detected motor angle θ is the rotation sensor 21 (step S40), the motor angle θ is motor angular speed ω is calculated is input to the motor angular velocity calculation unit 100 (step S41). The motor angular velocity ω motor angular acceleration α is input to a motor angular acceleration calculation unit 101 is calculated (step S42), the vehicle speed Vel is inputted (step S43). The motor angular velocity ω is input to the cut-off frequency varying unit 111A and 112A, the vehicle speed Vel also input to the cut-off frequency varying unit 111A and 112A, the motor angular acceleration α is input to the filter 113 and 114.
[0052]
　Then, the frequency determined according to the motor angular velocity ω according to the characteristics shown in FIGS. 12 and 13, the weighted average of the frequency determined in accordance with the vehicle speed Vel, the cutoff frequency controller 111A to vary the cut-off frequency fc1 ( step S44). Cut-off frequency fc1 that is set is input to the filter unit 113, the motor angular acceleration α is filtering processing in accordance with the cut-off frequency fc1 by the filter unit 113 (step S45). Filtered signal processed by the filter 113 is input to the compensation steering torque generator 115, the signal processed compensated steering torque Tf is inputted to the subtraction unit 34A by the compensation steering torque generator 115, the steering torque Th is It is compensated (step S46).
[0053]
　Then, the frequency determined according to the motor angular velocity ω according to the characteristics shown in FIGS. 12 and 13, the weighted average of the frequency determined in accordance with the vehicle speed Vel, the cutoff frequency controller 112A to vary the cut-off frequency fc2 ( step S50). Cut-off frequency fc2 that is set is input to the filter unit 114, the motor angular acceleration α is filtering processing in accordance with the cut-off frequency fc2 by the filter unit 114 (step S51). Filtered signal processed by the filter unit 114 is inputted to the compensating current command value generation section 116, the signal processed compensated current command value If is input to the adder 34B in the compensation current command value generation section 116, current command value Iref is compensated (step S52).
[0054]
　The above operation is repeated until the end (step S53).
[0055]
　Thus, the cutoff frequency fc1 and fc2 of the filter unit 113 and 114 to allow the variable in the motor angular velocity ω and the vehicle speed Vel, set the low cut-off frequency at the time and slow steering steering holding, the cutoff frequency at the time of high-speed steering since the set such increases can be suppressed without deteriorating the characteristics of the high-frequency range of the motor, the vibration becomes a problem in a low frequency region of the motor (steering holding micro-vibration). That is, by effectively removing noise on the motor angular acceleration alpha, thereby improving the performance of the compensator. Thus, the steering feeling good electric power steering device is obtained.
[0056]
　While the above is a linear all variable characteristic of the cutoff frequency controller 111 and 112,111A and 112A, as shown in FIG. 15, a higher cut-off frequency fc1 or fc2 linearly until the motor angular velocity ω10 or .OMEGA.11, in motor angular velocity ω10 or ω11 larger area may be characteristic to increase the cut-off frequency fc nonlinearly. Moreover, high non-linear until the motor angular velocity ω10 or .OMEGA.11, it may be higher linear motor angular velocity ω10 or .OMEGA.11 larger area.
[0057]
　Although acquired from the rotation sensor such as a resolver connected to the motor angle to the motor in the above, it may be obtained from the steering angle sensor.
DESCRIPTION OF SYMBOLS
[0058]
1 handle
2 column shaft (steering shaft, the handle
shaft) 10 torque sensor
12 vehicle speed sensor
13 battery
20 motor
21 rotary sensor
30 control unit
(ECU) 31 torque control unit
35 the current control unit
100 motor angular velocity calculation unit
101 motor angular acceleration calculation unit
110,110A stability compensator
111, 111a, 112, 112a-cut frequency (fc) variable portion
113 and 114 filter unit
115 compensates for the steering torque producing section
116 compensation current command value generation section

The scope of the claims
[Claim 1]
A torque control unit for calculating a current command value on the basis of at least steering torque, the current to drive the motor by a current control system based on a command value, the steering system electric power steering apparatus adapted to assist control in,
a motor angular velocity calculator for calculating a motor angular velocity ω from the motor rotation angle, the motor angular acceleration calculation unit from the motor angular velocity ω calculates the motor angular acceleration alpha, based on the motor angular speed ω and the motor angular acceleration alpha a compensation steering torque and stability compensator for calculating a compensation current command value,
comprising the said compensating the steering torque compensated steering torque, compensating the current command value in the compensating current command value electric power steering apparatus characterized in that it is so.
[Claim 2]
The stability compensation section,
the first filtering processing said motor angular acceleration α in response to the first cut-off frequency variable unit, the cut-off frequency fc1 of the cut-off frequency fc1 on the basis of the motor angular velocity ω a filter section, a second filter for filtering said motor angular acceleration α in response to cut-off the second cut-off frequency controller for setting the frequency fc2, the cut-off frequency fc2 on the basis of the motor angular velocity ω and parts,
in the electric power steering apparatus of claim 1 being configured.
[Claim 3]
The first cut-off frequency variable unit, the cut-off frequency fc1 constant at motor angular speed .omega.1 below a becomes higher cut-off frequency characteristics linearly or non-linear in region exceeding the motor angular velocity .omega.1,
the second cut-off frequency variable unit, the motor angular velocity ω2 (> ω1) less the a constant cut-off frequency fc2 by the motor angular velocity .omega.2 higher linear or non-linear in more than area cutoff claim has a frequency characteristic 2 the electric power steering apparatus according to.
[Claim 4]
The first cut-off frequency variable unit increases the cutoff frequency fc1 in the motor angular velocity .OMEGA.10 less linearly, a becomes higher cut-off frequency characteristics linearly or non-linear in region exceeding the motor angular velocity .OMEGA.10,
the first variable cutoff frequency of 2, and the motor angular velocity ω11 (> ω10) the cut-off frequency fc2 by the following increases linearly, a becomes higher cut-off frequency characteristics linearly or non-linear in region exceeding the motor angular velocity .OMEGA.11 the electric power steering apparatus according to claim 2 are.
[Claim 5]
The compensation steering torque and further the vehicle speed Vel the calculation of the compensating current command value is used, and the cut-off frequency fc1 and setting claims are used, each said motor angular speed ω and the vehicle speed Vel to one fc2 the electric power steering apparatus according to.
[Claim 6]
Wherein the first cutoff frequency controller is a frequency fc11 determined by the angular velocity corresponding map showing the relation between the motor angular velocity ω and frequency determined by the vehicle speed corresponding map showing the relationship between the vehicle speed Vel and frequency was and a frequency arithmetic mean and frequency fcv11 adapted to the cut-off frequency fc1,
the angular velocity corresponding to the second cut-off frequency varying section, showing the relationship between the motor angular velocity ω and the frequency a frequency fc21 determined by the map, the vehicle speed Vel and claim a frequency arithmetic mean and frequency fcv21 determined by the vehicle speed corresponding map showing a relationship between a frequency adapted to a cut-off frequency fc2 5 the electric power steering apparatus according to.
[Claim 7]
The first cut-off angular correspondence map frequency controller is the frequency fc11 constant at motor angular Omega21 below, the a higher becomes the frequency characteristic linear or non-linear in region exceeding motor angular velocity Omega21,
the second angular correspondence map cutoff frequency controller is the motor angular velocity ω22 (> ω21) and the frequency fc21 constant below, the motor angular velocity Omega22 claim 6 which is a higher becomes the frequency characteristic linear or non-linear in the region of more than the electric power steering apparatus according to.
[8.]
The first cut-off angular correspondence map frequency controller is the frequency fc11 increases linearly with the motor angular speed Omega21 less, a higher becomes the frequency characteristic linear or non-linear in region exceeding the motor angular velocity Omega21,
the first 2 cutoff angular correspondence map frequency controller is the frequency fc21 increases linearly with the motor angular velocity ω22 (> ω21) hereinafter become higher becomes the frequency characteristic linear or non-linear in region exceeding the motor angular velocity Omega22 the electric power steering apparatus according to claim 6 are.
[Claim 9]
The first vehicle speed corresponding map of the cut-off frequency variable unit, the holding constant value fcv11 slow speed Vel11 following vehicle speed Vel, the slow speed Vel11 exceeded, in linear or non-linear at high speed in the vehicle speed Vel12 below decreased to frequency fcv12 ( ω31) the frequency fc32 is constant below, the motor angular velocity Omega32 claim 10 which is the higher becomes the frequency characteristic linear or non-linear in the region of more than the electric power steering apparatus according to.
[Claim 12]
The first cut-off angular correspondence map frequency controller is the frequency fc31 increases linearly with the motor angular speed Omega31 less, a higher becomes the frequency characteristic linear or non-linear in region exceeding the motor angular velocity Omega31, the first 2 cutoff angular correspondence map frequency controller is the frequency fc32 increases linearly with the motor angular velocity ω32 (> ω31) hereinafter become higher becomes the frequency characteristic linear or non-linear in region exceeding the motor angular velocity Omega32 the electric power steering apparatus according to claim 10 are.
[Claim 13]
The first vehicle speed corresponding map of the cut-off frequency variable unit, the holding constant value fcv31 slow speed Vel31 following vehicle speed Vel, the slow speed Vel31 exceeded, in linear or non-linear at high speed in the vehicle speed Vel32 below increased to the frequency fcv32 (> fcv31), the frequency characteristic of holding the frequency fcv32 a region exceeding the high speed of the vehicle speed Vel32, the second cut-off speed corresponding map of the frequency controller is slow the vehicle speed Vel holds a constant value Fcv41 vehicle speed Vel41 below than the slow speed Vel41, increases in a linear or non-linear at high speed in the vehicle speed Vel42 following to frequency fcv42 (> fcv41), frequency region exceeding the high speed of the vehicle speed Vel42 fcv42 to claim 11 or 12 has a frequency characteristic that holds the serial Electric power steering device.
[Claim 14]
Control device for an electric power steering apparatus according to any preceding claim which is a motor angular speed ω as calculated from the steering angle sensor 1 to 13.