JPS60234070A - Power steering controller - Google Patents

Abstract

PURPOSE:To prevent the sharp variation of a steering force by detecting the anomaly of the captioned apparatus from the relative relation between a steering assisting force adjusting signal and the signal for the current signal to a steering assisting force generating means and switching the closed-loop control to the opened-loop control. CONSTITUTION:The captioned apparatus is equipped with a standard-voltage characteristic generating circuit 2 which generates the adjusting voltage which varies according to the output of a car-speed sensor 1, and the output is input into an error amplifying circuit 3 and a back-up circuit 13. In the error amplifying circuit 3, the difference between the output of the above-described generating circuit 2 and the output of a measuring means (resistor 8 and amplifying circuit 9) which generates the measuring signal for the current signal to a linear solenoid 7 for generating a steering assisting force is obtained, and the difference is compared, in a comparison circuit 4, with the triangular-wave voltage of a triangular-wave oscillating circuit 5. The output of the comparison circuit 4 is input with the output of an anomaly detecting circuit (standard- voltage generating circuit 10 and comparison circuit 11) and a back-up circuit 12 into a selecting circuit 12, and the linear solenoid 7 is controlled by the output of the selecting circuit 12.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention measures the magnitude of the current that actually flows through the auxiliary force generating member and performs feedbank control to generate a current that is generated by the auxiliary force generating member. The present invention relates to a power steering control device that adjusts the magnitude of auxiliary force to a desired value.

[Background technology]

A power steering control device using a current feed bank includes an auxiliary force generating member that receives a current signal and generates a steering auxiliary force corresponding to the current signal, as exemplified in Japanese Patent Laid-Open No. 56-146473. , a power feeding means that receives a control signal and supplies the current signal of a magnitude corresponding to the control signal to the auxiliary force generating member in order to adjust the auxiliary force generated by the auxiliary force generating member; a measuring means for generating a measuring signal corresponding to the actual magnitude of the current signal supplied to the generating member; an adjusting signal generating means for generating an adjusting signal for adjusting the steering assist force; and adjustment means for applying the control signal to the power supply means for adjusting the auxiliary force in accordance with the relative relationship between the measurement signal and the adjustment signal generated by the adjustment signal generation means.

In addition, the same publication states that in order to avoid damage to the auxiliary force generating member or the power supply means due to excessive power when a problem occurs in the measuring means, the magnitude of the measurement signal or the control signal is determined in advance. A safety circuit is described which stops the function of the power supply means and cuts off the power supply to the auxiliary force generating member when it detects that the set range is exceeded.

In such a known device, it is possible to prevent damage to the auxiliary force generating member or the power supply means, but when the power supply is suddenly cut off, the generated auxiliary force suddenly disappears, so that the steering force suddenly decreases. This causes a change in weight.

[Purpose of the invention]

The present invention eliminates the above-mentioned problems and provides a power steering control device that is effective in preventing damage to the auxiliary force generating member or power supply means and preventing sudden fluctuations in steering force.

[Summary of the structure of the invention]

Therefore, in the power steering control device according to the present invention, in the configuration described at the beginning, it is detected that the relative relationship between the measurement signal by the measurement device and the adjustment signal by the adjustment device is outside the range measured in advance. a detecting means; in response to the relative relationship being outside the set range, the detecting means invalidates the measurement signal by the measuring means and generates an adjustment signal for adjusting the control signal for increasing or decreasing the auxiliary force; It is characterized by comprising: a backup means for applying the power to the power feeding means in response to an adjustment signal from the means.

According to one embodiment of the invention, the adjustment signal generation means and adjustment means, as well as the detection means and bank-up means, are all constructed using analog electrical circuits. but,
It is also possible to have a digital computer such as a microcomputer process at least part of the content processed by these analog circuits.

The auxiliary force generating member may be of a duty ratio control type whose feeding current is changed continuously or in multiple stages, or of a duty ratio control type in which the average current is changed continuously or in multiple stages. Good too.

The configurations of the power supply means and adjustment means corresponding to the various auxiliary force generating members can also be selected from among known methods.

The measuring means can use a voltage drop element for current-voltage conversion inserted into the power supply circuit that connects the power supply circuit, the auxiliary force generating member, and the power supply, but a voltage drop element for current-voltage conversion can be used. Elements or magneto-resistance conversion elements can also be used.

In one embodiment, the detection means includes an error extraction means that inputs the measurement signal from the measurement means and the adjustment signal from the adjustment signal generation means to configure the joint means, for example, an error amplification circuit constituted by an analog circuit. , and a comparing means for comparing the error signal obtained therewith with a preset reference signal. However, a comparison means for comparing the measurement signal and the adjustment signal may be provided separately from the error extraction means.

In one embodiment, the backup means is configured to obtain the control signal based solely on the regulation signal of the regulation signal generating means and in response to this regulation signal. In this case, the abnormality detection signal of the detection means is guided to the adjustment signal generation means, and instead of using the adjustment signal as it is when an abnormality is detected, a correction signal (for example, a constant value) related to the relative difference with the measurement signal is generated. may be subtracted from the magnitude of the adjustment signal.

When the bank-up means is activated, it is free to provide a means for indicating this to the driver.

〔Effect of the invention〕

According to the present invention, an abnormality in the device is detected based on the relative relationship between the measurement signal and the adjustment signal, and in this case, closed-loop control (
Since the feedback control) is switched to open-loop control, it is possible to prevent damage to the auxiliary force generating member or the power supply means, and it is also possible to prevent sudden fluctuations in the steering force due to sudden changes in the generated auxiliary force.

〔Example〕

In FIG. 1 showing a first embodiment of the present invention, reference numeral 1 is a sensor, 2 is a reference voltage characteristic generator, and the sensor 1 and the reference voltage characteristic generating circuit 2 constitute adjustment signal generating means. The sensor 1 is, for example, a vehicle speed sensor, and the reference voltage characteristic generating circuit 2 generates an adjustment voltage that changes depending on the vehicle speed. Note that it is possible to combine the reference voltage characteristic generating circuit 2 with, for example, a steering angle sensor other than the vehicle speed sensor so that the adjustment voltage can also be changed depending on the steering angle or the like.

3 is an error amplification circuit, 4 is a comparison circuit, and 5 is a triangular wave oscillation circuit, and these circuits 3 to 5 constitute an adjusting means.

The control signal appearing at the output of the comparator circuit 4 is applied via the selection circuit 12 to the load drive circuit 6 as a power supply means. The load drive circuit 6 is connected to an on-vehicle battery, and supplies a current of a magnitude corresponding to the control signal from the selection circuit 12 to the glue near solenoid 7 as an auxiliary force generating member. The linear solenoid 7 is similar to a known type,
By bypassing the supply flow rate from a pump (not shown) to the power steering gear box, the opening degree of the valve is changed in accordance with the magnitude of the supplied current, thereby adjusting the steering assist force.

The ground side of the linear solenoid 7 is connected to the car body ground via a current cable, but a resistor (voltage effect element) 8 for changing current and voltage is inserted and connected in the line, and the voltage signal generated at the resistor 8 is It is amplified via the amplifier circuit 9 and given to the error amplifier circuit 3 as a measurement voltage. The resistor 8 and the amplifier circuit 9 constitute a measuring means.

The selection circuit 12 is normally in a state of selecting an input so that the output signal of the comparison circuit 4 is applied to the load drive circuit 6. At this time, the error amplifier circuit 3, the comparison circuit 4, the oscillation circuit 5, the power supply circuit 6, the resistor 8, and the amplifier circuit 9 reduce the supply current of the linear solenoid 7 in order to reduce the auxiliary force in response to the increase in vehicle speed. let Feedback control is then performed so that the supplied current becomes a value corresponding to the vehicle speed (such that the supplied current is decreased by increasing the measured supplied current, and the supplied current is decreased by decreasing the measured supplied current).

To be more specific, the output voltage of the error amplification circuit 3 increases in the direction (
(for example, to a larger value), the current supplied to the linear solenoid 7 increases accordingly, and when the measurement signal increases, the output voltage of the error amplification circuit 3 changes in the direction that the relative difference decreases, and an appropriate value is determined. Stable in equilibrium.

In the comparison circuit 4, the output voltage of the error amplifier circuit 3 and the triangular wave voltage of the oscillation circuit 5 are compared. The triangular wave voltage has a constant period and a constant wave height, and a pulse train signal with a duty ratio corresponding to the magnitude of the output voltage of the error amplification circuit 3 appears at the output of the comparison circuit 4.

When this pulse train signal is applied to the load drive circuit 6 via the selection circuit 12, the load drive circuit 6 turns on and off the power to the linear solenoid 7 in accordance with the on/off states of the pulse train signal. The linear solenoid 7 is intermittently energized, but since the period of the triangular wave voltage is selected to be sufficiently short, the opening degree of the valve is adjusted to correspond to the average value of the supplied current. In this way, the steering assist force is accurately controlled in response to adjustment signals such as vehicle speed.

According to the invention, the selection circuit 12 is controlled by circuit means for detecting abnormalities, indicated at 10 and 11, and cuts off the input from the comparator circuit 4 when an abnormality is detected. Connect with circuit means.

Reference numeral 10 denotes a reference voltage generation circuit that generates a reference voltage for the output voltage of the error amplification circuit 3, and is composed of voltage dividing resistors and the like.

The magnitude of the reference voltage is set in advance so that the relative difference between the adjustment signal and the measurement signal represented by the output voltage corresponds to the lowest value representing an abnormal state. In the embodiment, the magnitude of the reference voltage is set to a value that matches the peak height value of the square wave voltage generated by the triangular wave oscillation circuit 5.

The reference voltage is compared with the actual output voltage of the error amplifier circuit 3 in the comparison circuit 11, and when the output voltage exceeds the reference voltage, a command signal is given to the selection circuit 12 to connect the bank amplifier circuit 13 to the input. . Therefore, selection circuit 1
2 is composed of two gates 12A and 12B that are opened complementary to each other, as shown in FIG. 2, for example.

The bank amplifier circuit 13 is configured as a comparison circuit that compares the adjusted voltage of the reference voltage characteristic generation circuit 2 and the triangular wave voltage of the triangular wave oscillation circuit 5.

Therefore, a pulse train signal whose duty ratio corresponds only to the adjustment voltage and does not depend on the measurement voltage appears at the output of the bank amplifier circuit 13.

Therefore, in the selection circuit 12, the backup circuit 1
If 3 is selected, the current supplied to the linear solenoid 7 changes in accordance with the adjustment voltage.

To summarize the operation of this device, first, when the current flowing through the linear solenoid 7 is feedback-controlled to a normal value in accordance with the vehicle speed, the output voltage of the error amplification circuit 3 is determined by the adjustment signal and the measurement signal. Since there is no abnormality in the relative difference between the comparison circuit 11 and the comparison circuit 11, the selection circuit 12 maintains the state in which the output of the comparison circuit 4 is selected as an input.

During feedback control, if the ground line of the linear solenoid 7 falls to the ground without passing through the resistor 8, the amplifier circuit 9
The measured voltage that occurs has the same value when the supply current of the linear solenoid 7 is zero. Therefore, the output voltage of the error amplification circuit 3 changes in the direction of increasing the supplied current, and as a result, the maximum current tends to continue to be supplied to the linear solenoid 7.

At this time, the comparison circuit 11 according to the present invention selects the selection circuit 1
2 to the input from the back amplifier circuit 13, the feedback control is stopped at this point. Instead, the back amplifier circuit 13 is the reference voltage characteristic generating circuit 2.
The current supplied to the linear solenoid 7 is determined in response to the adjusted voltage from the linear solenoid 7. Thus, the system is switched from closed-loop control to open-loop control, and the steering assist force continues to be controlled according to conditions such as vehicle speed without sudden fluctuations.

In the apparatus of the embodiment described above, it is easy to modify the details of the circuit means within the scope of the gist of the present invention.

For example, in the second embodiment shown in FIGS. 3 and 4, the details of the location and role of the selection circuit 12 are changed. That is, the selection circuit 12 is arranged between the output of the error amplification circuit 3 and the input of the comparison circuit 4, and the selection circuit 12
The output voltage of the reference voltage characteristic generating circuit 2 and the adjustment voltage of the reference voltage characteristic generating circuit 2 are selected. For this purpose, the circuit includes, for example, two analog gates 12G.

12D.

Furthermore, the above 1. In the second embodiment, a signal representing the detection of an abnormality in the comparator circuit 11 may be additionally led to the reference voltage characteristic generating circuit 2 to correct the adjusted voltage when an abnormality is detected.

For example, as shown in FIG. 5, the adjustment voltage is corrected to decrease at a constant rate by connecting a normally closed switch that responds to the detection signal from the comparator circuit 11 in parallel with one of the voltage dividing resistors. be able to.

Note that when carrying out the present invention, the embodiments are not limited to those described in the explanation of the above-mentioned embodiments, and the suggestions mentioned in the explanation of the outline of the structure of the invention may be used as necessary within the scope of the scope of the claims. It is possible to modify the embodiment with reference to the following points.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a first embodiment of the present invention, Fig. 2 is an electrical wiring diagram showing details of the main parts of Fig. 1, and Fig. 3 shows a second embodiment of the invention. 4 is a block diagram, FIG. 4 is an electrical wiring diagram showing details of the main part of FIG. 3, and FIG. 5 is an electrical wiring diagram of the main part showing an additional modification of the first or second embodiment. 1.2...Vehicle speed sensor and reference voltage characteristic generation circuit forming adjustment signal generation means, 3,4.5...Error amplification circuit, comparison circuit, and triangular wave oscillation circuit forming adjustment means, 6...Power supply means 7... A near solenoid serving as an auxiliary force generating member; 8, 9... A resistor and amplifier circuit serving as a measuring means; 10.11... A reference voltage generating circuit serving as a detecting means. Comparison circuit, 12.13... Selection circuit and bank up circuit forming backup means. Representative Patent Attorney Takashi Okabe Figure 2 1n Figure 3 Figure 4 n Figure 5

Claims (1)

[Claims] An auxiliary force generating member that receives a current signal and generates a steering auxiliary force corresponding to the current signal, and a control signal that receives a control signal to adjust the auxiliary force generated by the auxiliary force generating member. power feeding means for supplying the current signal having a magnitude corresponding to the control signal to the auxiliary force generating member; and generating a measurement signal corresponding to the actual magnitude of the current signal supplied to the auxiliary force generating member. a measuring means, an adjusting signal generating means for generating an adjusting signal for adjusting the steering assist force, and the above-mentioned measuring means corresponding to the relative relationship between the measuring signal by the measuring means and the adjusting signal by the adjusting signal generating means. In the power steering control device, the power steering control device includes: an adjusting means for applying the control signal to the power feeding means for adjusting the auxiliary force; detection means for detecting that the relative relationship is outside the preset range; and the detection means disables the measurement signal by the measurement means in response to the relative relationship being outside the preset range. and backup means for applying the control signal for adjusting the auxiliary force to the power supply means in response to the adjustment signal from the adjustment signal generation means.