JPS60197468A - Power steering apparatus - Google Patents

Abstract

PURPOSE:To prevent the sharp variation of steering force by carrying-out steering force control only according to the car traveling conditions, when an input/ output detecting apparatus is put into trouble. CONSTITUTION:When the anomaly of a detecting apparatus is judged by a trouble judging means, a car-speed signal (a), steering torque signal (b), and an assist hydraulic pressure signal (c) are made zero by a cancellation means. Then, a flow-rate control valve 4 is operated by the electric current value determined on the basis of the car-speed signal (a) only, and steering-force control is performed. Since steering-force control is performed only by the car-speed signal, abnormal steering-force characteristic is not represented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a power steering system in which the steering force is controlled by a hydraulically or electrically actuated actuator.

PRIOR ART Conventional power steering devices include hydraulically driven ones and electrically driven ones, for example.

Japanese Patent Application No. 58-155821 shows a hydraulically driven device. As shown in Fig. 1, this is a power steering system 1 that controls the steering force according to vehicle running conditions, and reduces the flow rate of hydraulic oil in response to steering operations as the vehicle speed signal increases, making it suitable even when driving at high speeds. The purpose of this is to obtain a certain amount of steering power. In other words, the flow rate supplied to the power cylinder 2 and the control valve 3 is controlled by the solenoid 4 of the flow rate control valve 4.
It is controlled by the drive current directly applied to a.

The power cylinder 2, control valve 3, and flow rate control valve 41C constitute an actuator.

Further, the drive current rfi is determined by the vehicle speed signal a.The required oil pressure is determined by the vehicle speed signal a, and the required oil pressure is stored in the memory circuit of the computer 5 based on the vehicle speed signal a. It is configured to correct the direct drive current. In addition, 6 in the figure is a constant flow pump.

The steering force control is performed according to the block diagram shown in FIG. 2 and the flowchart shown in FIG. 3. That is, the second
The block diagram shown in FIG. Calculate the corrected current value. It should be noted that a control correction means 12 is constituted by the memory circuit IO and the sleeve straightness calculation circuit 11. Then, the correction current amount calculated by the correction rrM calculation circuit 11 and the vehicle speed signal a
Directly operates the flow rate control valve 4 to control the amount of hydraulic oil supplied to the control valve 3 according to the sum of the drive current amount determined by the control means '1 flow [direct detection circuit 13]. The target assist hydraulic pressure is supplied to the control valve 3 and the power cylinder 2. The flowchart shown in FIG. 3 shows the processing by the microcomputer 5. In the flowchart shown in FIG. ?@Calculate the current value l.

In step 21, the required oil pressure P1 is calculated from the vehicle speed and torque. On the other hand, in the one-hour interrupt program, the vehicle speed signal is read in step 30, the soft rudder torque signal is read in step 31, and the assist oil pressure signal P is read in step 32.

Load. Then, the necessary oil pressure signal P calculated by the main program in step 33 based on each of these signals.
, and the assist oil pressure signal P8, and based on this difference in oil pressure store number, a corrected first flow rate Δi is calculated in step 34. Next, in step 35, the corrected flow rate Δi and the drive first flow determined in the main program are calculated. II! The sum with 1 is calculated and output.

However, in such a conventional power steering system ++11, even if the input and output detection means for detecting the steering wheel 8@b and the assist oil pressure signal C fail.

Steering force control is corrected based on incorrect data from the failed detection means. Therefore, if the TftlJ control is performed by such a malfunctioning "output product" means, the original and proper one-wheel steering force control will not be performed.

Purpose of the Invention In view of the conventional situation, the present invention provides that when an output detection device fails, this person excludes data from the output detection means and does not perform correction based on the data. It is an object of the present invention to provide a power steering system iIl that controls steering force using signals based only on vehicle running conditions.

1. The structure of the present invention for achieving the above object will be described based on the concept 1 of the invention shown in FIG.

That is, in the power steering-JA- of the present invention, the actuator A
a control means B for controlling the actuator according to inputs from vehicle running conditions such as vehicle speed, means C and D for respectively detecting the input and the output, and input signals or outputs. In the power steering system ZE, the power steering system is equipped with a means E for feeding back a signal and correcting the control by the control means B, a means F for determining a failure of the input/output detection means, and a means F for determining a failure of the input/output detection means; It is constructed by providing a means G for canceling the control correction by a person and an output signal when the detection means C and D are determined to be malfunctioning.

EMBODIMENT OF THE INVENTION Below, the embodiment of the present invention will be explained in detail based on the drawings. Incidentally, in explaining this embodiment, the same parts as those in the conventional configuration will be described with the same reference numerals.

That is, FIGS. 5 and 6 are control block diagrams and flowcharts showing one embodiment of the power steering device of the present invention,
In this embodiment, as shown in FIG. 5, a failure determination means 42 is provided for comparing the steering torque signal obtained from the input detection means 40 and the assist oil pressure signal C obtained from the output detection means 41. The failure determining means 42 determines whether the steering torque detecting device or the assist hydraulic pressure detecting device is normal or abnormal based on the oil pressure-torque characteristic shown in FIG. That is, the shaded area in FIG. 7 indicates the control range P of the hydraulic pressure-torque characteristic when the flow rate is controlled, and the failure determining means 42 indicates the hydraulic pressure-torque characteristic control range P.
When the torque characteristic point is within the control range P, the steering torque and assist oil pressure detection devices t are determined to be normal, while the characteristic point is, for example, within the control range P as indicated by the X mark in the figure. F) When the detection device is outside the range P, the detection device determines that there is an abnormality.

Then, the steering torque is determined by the failure determining means 42.

If it is determined that the assist oil pressure detection device is normal, steps 30 and 31 are performed as shown in FIG. 6B.

In step 32, the vehicle speed signal a, the steering torque signal S, and the assist oil pressure signal C are read, and since the detection device is normal, the hydraulic correction value is calculated in step 33 based on the signals a, b, and o, as in the conventional case. As a result, in step 34, the correction 'wL flow rate Δ1 is calculated.

Next, if the failure determination means 42 determines that the detection device is abnormal in step 51, each of the signals a
, b, and o are set to O by the cassette means 43 provided between the block 11 and the block 4 in FIG. 4 (see FIG. 5) is activated, and steering force control is performed. Therefore, since the steering force control is performed only by the vehicle speed signal a, delicate control is not performed, but abnormal steering force characteristics are not exhibited. In the above embodiment, a hydraulic power steering device is shown, but an electric power steering device using an electric motor as an actuator may be used.

As described in detail, in the power steering system of the present invention, in the event that the input/output detection device fails, the signal from the input/output detection device is excluded and the original vehicle running conditions such as vehicle speed are detected. Since the steering force control is performed only based on the steering force characteristics, the steering force characteristics do not show any abnormal behavior, and there is an excellent effect that sudden changes in the steering force can be prevented and safety can be improved.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an example of a power steering device, Fig. 2 is a block diagram showing conventional steering force control, Fig. 3 is a flowchart showing conventional steering force control, and Fig. 4 is a conceptual explanation of the present invention. Fig. 5 is a block diagram showing an embodiment of steering force control of the present invention, Fig. 6 is a flow chart showing an embodiment of steering force control of the present invention, and Fig. 7 is a hydraulic pressure during steering force control. - It is a graph showing the permissible range of torque characteristics. 1... Power steering bag ffi, 2... Power cylinder (actuator), 3... Control box (actuator), 4... Flow rate control valve (actuator),
5... Micro combinator, 12... Control corrector m, ta... Current [calculation circuit (control means), 40...
- Input detection means, 41... Output detection means, 42...
Failure determination means, 43... Cancellation means. No. 6 @ 'A) ...) To Nuizobtsu 7"-7 Time 〢 11 included h pufgram □ gIrIPI interrupt tou 4F 4 chemical grade appropriate portion tor 74 number from medium speed Salvation i Kusum ni 1 * ff 14 (P2) inspection εe2 reward 3 YES (Pi-P2) ,,I,. Mouth 1 --m=-, --- t) Rec

Claims (1)

[Claims] (1) An actuator that assists the steering force, a control means that controls the output generated by this actuator according to vehicle running conditions such as vehicle speed, a means that detects the input by the steering torque etc. and the output, respectively, and the input 1i. means for feeding back the signal or output signal to correct the control by the pre-control means; means for determining a failure of the input/output detection means; and means for determining the input/output detection means. It was determined that the output horizontal narrowing means was malfunctioning, and two people went to work. A power steering device comprising means for canceling control failure caused by an output signal.