JPS6334287A - Power steering control device - Google Patents

Abstract

PURPOSE:To securely detect the abnormality of a system by sensing the variation in steering force by body and inspecting the abnormality of a steering angle response type steering force control system. CONSTITUTION:A power steering device has a control device 16 which controls the driving current of a steering force varying actuator 14 to vary steering force, based on the detected signals of a vehicle speed sensor 10 and a steering angle sensor 12. The control device 16 has an ordinary mode which carries out the control of steering force in accordance with the detected steering angle thetaat the time of an ordinary operation and a diagnosis mode which is shifted from the ordinary mode and which diagnoses the abnormality of a steering angle response type steering force control system. And, the control device 16 can control the steering force in such a way that a steering angle depending quantity is larger as compared to the case of ordinary mode when shifted to the diagnosis mode, in order to sense the variation in steering force by body.

Description

[Detailed description of the invention]

[Industrial Field of Application 1 The present invention relates to a power steering control device, and in particular,
The present invention relates to an improvement in a power steering control device that controls a steering force so as to increase the steering force when the detected steering angle increases in accordance with the detected steering angle by a steering angle detection sensor. [Prior Art] In the power steering control tlll device for an automatic XRI, a vehicle speed-sensitive type is provided that controls the steering force according to medium speed in order to ensure an energized steering force according to the vehicle speed. This vehicle speed sensitive power steering device, for example, controls the drive current of a linear solenoid valve, which is an actuator for varying the steering force, using a control device such as a power steering computer based on a heavy speed signal from a vehicle speed sensor. The steering force is changed by controlling the steering force. Specifically, the steering force control 111 according to the vehicle speed is controlled based on the relationship between the vehicle speed V and the drive current value 1o of the solenoid valve, as shown in FIG. That is, as the vehicle speed V increases, the drive current value 1o of the solenoid valve is gradually decreased, and the steering force is increased as the vehicle speed increases. In this vehicle speed sensitive power steering Ll control device, from the viewpoint of improving steering performance, the steering is performed so that the steering force is increased when the steering angle increases, according to the detected steering angle by the steering angle detection lens I. A steering angle-sensitive steering force control device for controlling force may be added. In such steering angle-sensitive steering force control, the steering angle coefficient K is calculated from the detected steering angle θ based on the relationship between the detected steering angle θ and the steering angle coefficient as shown in FIG. , this steering angle coefficient K is multiplied by the drive current value 1o obtained based on the medium speed V from the relationship shown in FIG. I have to. Thereby, the set current value of the linear solenoid valve is corrected based on the detected steering angle θ. That is, when the detected steering angle θ from the steering center is within a certain range, the steering angle coefficient is set to 1, and when the detected steering angle θ from the steering center is detected within a predetermined range or more, the steering angle coefficient K is set to 1. is gradually decreased to the lower limit value A of the steering angle coefficient according to the detected steering angle θ. Therefore, when the detected steering angle θ detected by the steering angle sensor is within a predetermined range from the steering center, the steering angle coefficient is set to 1, and when the detected steering angle is outside the predetermined range and the steering angle is largely steered. In this case, the steering angle coefficient K is decreased according to the detected steering angle θ. Therefore, when the detected steering angle O becomes large, the set current value of the solenoid valve is reduced,
The steering force will be controlled 11 to increase it. However, in the above-mentioned steering angle sensitive steering force control system, the steering angle coefficient 1, which is changed according to the steering angle, is usually 1.
Therefore, since the lower limit value A of the steering angle coefficient is set to 0.7, the steering force variation due to the detected steering angle θ in normal steering angle sensitive steering force control is , it is not possible to reliably experience steering force control based on the detected steering angle θ. Therefore, it is difficult to check the operation of the steering angle detection sensor at the time of factory shipment inspection or operation check at a repair shop by feeling the fluctuations in the steering force! There is a problem that it is 1. In contrast, in the past, the abnormality diagnosis terminal (diagnosis terminal) was short-circuited, and the steering angle detection sensor diagnosis mode was set by operating a switch, and the indicator in the meter was turned on or off depending on the operating state of the steering wheel. , check the steering angle detection hinge. [Problems to be Solved by the Invention] However, in the above-mentioned conventional steering angle detection sensor diagnostic system, there is no display device such as an indicator or a buzzer that informs the inspector of the steering operation status in the diagnostic mode. There is a problem that the configuration is complicated. Note that in vehicles equipped with electronically controlled suspension, it is possible to use various lamps that display the status of the electronically controlled suspension during driving;
For vehicles not equipped with 1+J suspension,
Similar to the above, there is a problem in that a display device such as an indicator is required for inspection. In addition, in normal power steering control systems, there is little need to inform the driver of the operating status of the power steering control system during driving, and therefore various indicators that display the operating status of the system, such as front electronically controlled suspensions, are not used on meters. There is a problem that an indicator for inspection is required because it is not installed inside the vehicle. This poses a problem in that the number of parts increases and the device configuration becomes complicated. [Objective of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and is capable of steering angle-sensitive steering by sensing fluctuations in steering force without providing a dedicated display or the like. An object of the present invention is to provide a power steering control device that can reliably detect abnormalities in a force-controlled all system. (Means for Solving the Problems) The present invention provides a power steering control 21I that controls the steering force so as to reduce the steering force greatly when the detected steering angle increases, according to the detected steering angle by the steering angle detection sensor. The device has a normal mode in which steering force is controlled according to the detected steering angle during normal operation, and a diagnostic mode that is switched from this normal mode to diagnose abnormalities in the steering angle-sensitive steering force control system. The above object is achieved by controlling the steering force by increasing the steering angle dependence amount compared to the normal mode so that the steering force fluctuation can be experienced. In mode, when controlling the steering force by increasing the steering angle dependent amount, the lower limit value of the steering angle coefficient at the maximum steering angle is set to the minimum value in the stopped/low-speed driving state, and the lower limit value of the steering angle coefficient is set to the value of the vehicle speed. The lower limit of the steering angle coefficient is gradually increased as the vehicle climbs up to the lower limit of the steering angle coefficient at the maximum steering angle in normal mode.This is done by changing the lower limit of the steering angle coefficient based on the vehicle speed based on the relationship between vehicle speed and lower limit of the steering angle coefficient. .

[Effect]

In the diagnostic mode, the steering angle dependence amount is increased compared to the normal mode so that the steering force can be experienced as the steering force fluctuates based on the detected steering angle using the steering angle-sensitive steering force control system. The steering force is controlled by controlling the steering force. Therefore, it is possible to experience the fluctuations in the steering force as the steering wheel is operated, and thereby it is possible to easily check whether there is an abnormality in the steering angle sensitive steering force control system. Moreover, by actually experiencing the steering force fluctuations and checking for abnormalities in this control U11 system,
The conventional display device such as an indicator or a buzzer can be eliminated, and the number of parts can be reduced and the device configuration can be simplified. In addition, when controlling the steering force by increasing the steering angle dependence amount in the diagnosis mode, the lower limit value of the steering angle coefficient at the maximum steering angle is set to the minimum value in the stopped/low-speed running state, and the lower limit value of the steering angle coefficient is set to the vehicle speed. The lower limit value of the steering angle coefficient is changed according to the vehicle speed according to the vehicle speed - lower limit value pattern of the steering angle coefficient, which gradually increases to the lower limit value of the steering angle coefficient at the maximum steering angle in the normal mode as the steering angle increases. If you accidentally drive with the switching means for switching between normal mode and diagnostic mode set to diagnostic mode, for example, if you drive with the diagnostic terminal shorted, the vehicle speed may be in the medium to high speed range. In this case, the same steering force control as in the normal mode can be performed, and operational safety can be ensured. In addition, if you short-circuit the diagnosis terminal and operate in diagnostic mode, the vehicle will enter diagnostic mode when stopped or driving at low speed.
Although the steering force increases as the steering angle increases, safety is ensured because the vehicle is stopped or running at low speed. Furthermore, the lower limit value of the steering angle coefficient is ``gradually increased'' as the vehicle speed increases, up to the lower limit value of the steering angle coefficient at the maximum steering angle of 8 o'clock in normal mode, so the steering force changes as the vehicle speed increases. I don't have to worry about it. Therefore, safety is ensured in this respect as well. [Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, during normal driving, this embodiment has the vehicle speed-drive current value relationship shown in FIG. 4 above, and the detected steering angle-steering angle coefficient relationship shown in FIG. 5 above. Based on
It is comprised of a control device 16 that controls the drive current of the actuator tacho 4 for varying the steering force based on detection signals from the speed sensor 10 and the steering angle detection sensor 12 to change the steering force. This ff, +control device] 6 is used to switch between a normal mode in which the steering force is controlled according to the detected steering angle θ during normal operation, and a diagnostic mode in which to diagnose abnormalities in the steering angle sensitive steering force control system. A diagnosis terminal 18 is provided. The control device 16 has a normal mode in which the steering force is controlled according to the detected steering angle θ during normal operation, and a diagnostic mode that is switched from the normal mode and diagnoses an abnormality in the steering angle-sensitive steering force control system. When switching to the diagnostic mode, the steering force is controlled by increasing the steering angle dependence amount compared to the normal mode so that the steering force fluctuation can be experienced. The specific steering force control in the diagnosis mode in this control device 16 is performed by changing the steering angle coefficient lower limit value A depending on the vehicle speed V, based on the relationship between the vehicle speed and the lower limit value of the steering angle coefficient shown in FIG. is being used. The relationship between the vehicle speed and the lower limit value of the steering angle coefficient is such that the lower limit value A of the steering angle coefficient at the maximum steering angle is zero in the stopped/low-speed driving state, and the lower limit value A of the steering angle coefficient is set to the maximum value in the normal mode as the vehicle speed increases. The steering angle coefficient is gradually increased to the lower limit value at the time of steering angle. Next, the processing flow for steering force control in the control tlI device 16 will be explained with reference to FIG. First, the program is started at step 100. Next, the process proceeds to step 102, where various parameters such as vehicle speed and steering angle are initialized. Next, the process proceeds to step 104, where the vehicle speed V is calculated based on the detection signal of the vehicle speed sensor 10, and the steering angle detection sensor 12
The detected steering angle θ is calculated based on the detected signal. Next, the process proceeds to step 106, where it is determined whether the diagnosis terminal is short-circuited. This step 106
If it is determined that the diagnosis terminal is not short-circuited, the process proceeds to step 108. In step 108, the actuator 14 is driven and controlled according to the normal mode. Also, if it is determined to be positive in step 106,
That is, if it is determined that the diagnosis terminal 18 is short-circuited, the process proceeds to step 110. Step 11
0, the actuator 14 is driven and controlled according to the aforementioned diagnosis mode. Hereinafter, steps 104 to 110 are cyclically processed. Next, the operation of this embodiment will be explained. First, steering force control ALL in the normal mode will be explained. The steering force is controlled by changing the drive current value I of the actuator 14. This drive current value I is
It is obtained as the product of the drive current value 1° obtained from the figure and the steering angle coefficient obtained from the above-mentioned Fig. 5 (1=IoXK
). Therefore, during normal driving, the drive current value 1o decreases as the vehicle speed V increases, and as a result, the steering force increases. Furthermore, when the detected steering angle θ becomes large, the steering angle coefficient K decreases from 1 as the detected steering angle θ increases, and as a result, the drive current value I decreases as the detected steering angle θ increases. This results in an increase in steering force. Therefore, an appropriate steering force is applied according to the vehicle speed (2) and the detected steering angle (theta), and the steering performance can be improved. Next, steering angle force control in the diagnosis mode will be explained. First, a case where the steering angle sensor 10 is normal will be described. When the vehicle speed V is zero or in a low speed region, the drive current value I is maximum (Iomax). In this state, when the detected steering angle θ is small, the steering angle coefficient becomes 1, and the load current I becomes maximum<Iomax). Therefore, the steering force becomes smaller. Similarly, when the vehicle speed is zero or in a low speed region,
When the steering angle becomes large, the steering angle coefficient becomes zero in this case, so the drive current value I becomes zero. Therefore, the steering force will increase. In this way, if the vehicle speed is close to zero and you can feel that the steering force is small when the steering angle is small, and the steering force is large when the steering angle is large, there is an abnormality in the steering angle sensor, etc. It can be determined that there is no such thing. In this way, it is possible to determine whether there is an abnormality in the steering angle-sensitive steering force control system by experiencing the magnitude of the steering force, so it is possible to eliminate the need for indicators and other indicators for inspection as in the past. , the device configuration can be simplified. Next, the case where the steering angle sensor is defective will be explained. In this case, since the driver can experience fluctuations in the steering force that are different from those when the steering angle sensor 12 is normal, it can be determined that the steering angle sensor is defective. Next, a case will be described in which normal scanning is continued while the diagnosis terminal 18 is erroneously short-circuited. In this case, as is clear from the above-mentioned FIG. Curve B is the steering angle coefficient lower limit value straight line C in normal mode (as the steering angle coefficient lower limit value A is constant at 0.7, it is a straight line)
Since this is the same at vehicle speeds of 40 ku+/H or higher, the same steering force control as in the normal mode can be performed in the speed range of vehicle speeds of 40 km/H or higher. Furthermore, when the vehicle speed is zero or in a low speed region, the detected steering angle θ increases to the extent that the steering force can be felt when the driver is in the driver's seat, compared to the normal mode. Since the vehicle is stopped or running at low speed, even if the steering force increases in this way, there is no problem in running and safety can be ensured. Furthermore, since the steering force gradually decreases when the vehicle speed shifts from zero or a low speed range to a high speed range, the problem that the steering force changes by D after a certain vehicle speed does not occur. In the above embodiment, the lower limit of the steering angle coefficient in the diagnostic mode is set to 11'i A lj, but the present invention is not limited to this, and for example, the steering angle coefficient in the diagnostic mode is The candy may be larger than zero as long as the value is good enough to allow the user to feel the change. [Effect of the invention 1] As explained above, if the present invention is applied, the steering angle is sensitive! 1
The normal operation of the steering force control system can be checked by experiencing the fluctuations in the steering force. This has the excellent effect of making it possible to perform inspections reliably.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the power steering control device according to the present invention, FIG. 2 is a diagram showing the vehicle speed-steering angle coefficient lower limit relationship in diagnostic mode and normal mode, and FIG. 14 is a flowchart showing the control of the control II in the same embodiment, and FIG. Fig. 5 is a diagram showing the relationship between the steering angle and the steering angle coefficient in the conventional steering angle sensitive steering force control. 10... Vehicle 7t = sensor, 12... Rudder angle detection sensor, 17' l...Actuator, 16...Control device, 18...Diagnosis terminal.

Claims (2)

[Claims] (1) In a power steering control device that controls the steering force so that the steering force is increased when the detected steering angle increases according to the detected steering angle by a steering angle detection sensor, the power steering control device controls the steering force according to the detected steering angle during normal driving. It has a normal mode that controls force, and a diagnostic mode that can be switched from this normal mode and diagnoses abnormalities in the steering angle-sensitive steering force control system.In the diagnostic mode, the steering force control system is compared to the normal mode so that you can experience the steering force fluctuations. A power steering control device that controls steering force by increasing a steering angle dependence amount. (2) In the diagnosis mode, when controlling the steering force by increasing the steering angle dependent amount, the lower limit value of the steering angle coefficient at the maximum steering angle is set to the minimum value in the stopped/low-speed running state, and the lower limit value of the steering angle coefficient is A patent that changes the lower limit value of the steering angle coefficient based on the vehicle speed based on the relationship between vehicle speed and lower limit value of the steering angle coefficient, in which the value gradually increases as the vehicle speed increases to the lower limit value of the steering angle coefficient at the maximum steering angle in normal mode. A power steering control device according to claim 1.