JPH069978B2 - Steering force control device for electronically controlled power steering - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronically controlled power steering steering force control device capable of obtaining an appropriate steering feeling according to a traveling state of a vehicle or a steering condition.

Conventional technology As a method to change the steering force of power steering,
A method of controlling the flow rate of the pressure liquid flowing into the control valve, and an input shaft that determines the opening of the control valve by controlling the equivalent spring constant between the input shaft and the output shaft with the reaction pressure of the hydraulic reaction chamber. A hydraulic reaction chamber system that changes the relative displacement of the output shaft and changes the steering force accordingly (for example, Japanese Patent Publication No.
No. 43946) is known, and all of them control the flow rate and the reaction pressure by changing the opening of the orifice in the hydraulic circuit. A linear solenoid, a stepping motor, a DC servomotor, or the like is used as an actuator for controlling the opening of the orifice.

As described above, since the steering force of the power steering changes due to various external factors, in order to obtain a proper steering feeling, the opening degree of the orifice is controlled according to the factor, and the steering force is adjusted appropriately. Need to keep. The control amount of this orifice is the weight of the vehicle, the number of passengers, the load, etc.
It depends on the characteristics of the vehicle, the characteristics of the steering (hydraulic system characteristics, mechanical characteristics), and the preferences of the automobile manufacturer. In order to deal with this, conventionally, the circuit constants that determine the relationship between the vehicle speed signal and the orifice control amount and the shape of the orifice are finely adjusted.

The problem to be solved by the invention However, in such a countermeasure, the manufacturer supplying the control device to the consumer must design the control device individually according to the external factors as described above. In addition, problems such as increased cost and longer development period (rework by tuning the vehicle and steering device) remain.

The present invention is capable of obtaining an appropriate steering force according to changes in various external elements such as a running state of a vehicle and a steering condition,
It is an object of the present invention to provide a steering force control device for an electronically controlled power steering, which enables quick response to the above external elements in design and enables standardization of a control circuit.

Means for Solving the Problems One of the steering force control devices for electronically controlled power steering according to the present invention is configured to change the steering force by controlling the opening of an orifice in a hydraulic circuit. In a steering force control device for a power steering, an actuator driving means for driving an actuator of the orifice and a plurality of external elements related to the steering force, at least one of which is a steering angle, are given to each element as a set. Storage means for storing the relationship between the value and the opening control amount of the orifice corresponding to the steering force corresponding to the value, a plurality of detection means for detecting the values of the plurality of external elements, Of the steering angle signal output by one of the detection means for a specific period of time, the average value thereof is taken, and this value is taken as the zero position of the steering angle, and Steering angle signal correction means for obtaining the absolute value of the difference between the steering angle signal from one of the number detection means and the average value defined as the zero position, and detection corresponding to external elements other than the steering angle. And an access means for reading an orifice opening control signal from the corresponding storage area of the storage means on the basis of the output of the means and the output of the steering angle signal correction means and inputting the signal to the actuator drive means. It has a configuration of a steering force control device for an electronically controlled power steering.

Further, another one of the steering force control devices for electronically controlled power steering according to the present invention controls the equivalent spring constant between the input shaft and the output shaft by the reaction force pressure of the hydraulic reaction chamber to control the control valve. In a steering force control device for a power steering, which changes a relative displacement amount of an input shaft / an output shaft that determines an opening degree, and thereby changes a steering force, a hydraulic circuit for supplying a hydraulic fluid to the reaction force chamber. Actuator drive means for adjusting and driving the opening of the orifice in the inside, and concrete values given to each element as a set of a plurality of external elements related to the change of the steering force and at least one of which is a steering angle A storage unit that stores the relationship between the opening control amount of the orifice corresponding to the corresponding steering force in a table, a plurality of detection units that detect the values of the plurality of external elements, and a plurality of the detection units. One of them Of the steering angle signal for a specific period of time, takes an average value thereof, and sets this value as the zero position of the steering angle, and at the same time, determines the steering angle signal from one of the plurality of detecting means and the zero position. Steering angle signal correction means for obtaining the absolute value of the difference between the determined average values, and correspondence of the storage means based on the output of the detection means corresponding to external elements other than the steering angle and the output of the steering angle signal correction means. The steering force control device for an electronically controlled power steering is characterized in that it has an access means for reading an orifice opening control signal from a memory area and inputting the signal to the actuator driving means.

Effect The steering force control device for a power steering according to the present invention has the above-mentioned configuration and is related to a change in the steering force by at least 1
The values of a plurality of external elements, one of which is the steering angle, are detected by a plurality of detecting means, the steering angle signal output by one of the plurality of detecting means is sampled for a specific time, and an average value thereof is calculated. And a steering angle signal correction means for determining an absolute value of a difference between a steering angle signal from one of a plurality of detection means and the average value defined as the zero position. A specific value given to each element as a set of a plurality of external elements related to the change of the steering force, based on the output of the detection means corresponding to the external elements other than the steering angle and the output of the steering angle signal correction means. And the orifice control signal is read by the access means from the corresponding storage area of the storage means that stores the relationship between the opening control amount of the orifice in the hydraulic circuit corresponding to the steering force and the corresponding steering force. This Driving the actuator of the orifice and enter the Chiyueta driving means, it is possible to obtain Yotsute, a proper steering force in response to changes in various external elements to control the opening degree of the orifice.

Further, another one of the steering force control devices for a power steering according to the present invention is configured as described above, and detects the values of a plurality of external elements related to the change of the steering force by a plurality of detecting means to obtain a steering angle signal. The correcting means samples the steering angle signal output by one of the plurality of detecting means for a specific time, takes an average value thereof, and sets this value as the zero position of the steering angle, and at the same time, the plurality of detecting means. Of the steering angle signal from one of the steering angle signal and the zero position, the absolute value of the difference between the average value determined, and the output of the detection means corresponding to an external element other than the steering angle and the steering angle signal correction means. Based on the output
A specific value given to each element as a set of a plurality of external elements, at least one of which is the steering angle, which is related to the change in the steering force, and the opening degree of the orifice in the hydraulic circuit corresponding to the corresponding steering force. The orientation control signal is read by the access means from the corresponding storage area of the storage means that stores the relationship with the control amount in the form of a table, and this is input to the actuator drive means to drive the actuator of the orifice.
The opening of the orifice is controlled.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 is a system diagram of the steering force control device of this embodiment, in which the steering gear has a power assist mechanism including a rack cylinder 1, a control valve 2, and the like. The main pump 3 is constantly rotatably driven by the engine 4 via the pulley 5 and the like while the engine 4 is rotating, pressurizes the fluid in the tank 6, and supplies the pressurized fluid to the control valve 2 of the power assist mechanism. , And recirculates to the tank 6. 7 is a sub pump,
Like the main pump 3, the engine 4 is always rotationally driven to pressurize the fluid in the tank 6 and supply the pressurized fluid to the hydraulic reaction force chamber 8.

The hydraulic reaction force chamber 8 receives the supplied pressure fluid and changes the equivalent spring constant between the handle shaft (input shaft) 9 and the shaft (output shaft) on the steering gear side. The control valve 2 whose opening is determined by the relative displacement of the shaft is controlled by the reaction force pressure of the hydraulic reaction chamber 8, and 10 is the reaction pressure of the hydraulic reaction chamber 8. The opening of the orifice 10 is controlled by a control signal output from the control circuit 11.

The steering force of the power steering changes depending on external factors such as the running condition of the vehicle (road bending, road surface condition, occupant condition, load capacity, vehicle speed, etc.) and steering conditions. An actual measurement value of a plurality of the external elements is input to 11 and a control signal corresponding to this input is output to control the opening of the orifice 10. In this embodiment, the vehicle speed and the steering angle are selected as external factors. 12 is a vehicle speed sensor,
The rotation of the output shaft of the transmission 13 is electrically detected, and the vehicle speed signal is input to the control circuit 11. 1
Reference numeral 4 denotes a steering angle sensor, which is composed of a potentiometer and the like, and a fixed side such as a case is provided in a fixed portion around the handle, while a sliding side is fixed to the handle shaft 9,
The steering angle is detected as a voltage signal, for example, and the steering angle signal is input to the control circuit 11.

FIG. 2 is a block diagram showing a schematic configuration of the control circuit 11, in which reference numeral 15 is a microcomputer. The microcomputer 15 has a storage element 15a for storing the relationship between each value of the vehicle speed signal and the steering angle signal and the corresponding orifice opening control amount corresponding to the steering force as a table as shown in FIG. An access circuit section 15b is provided for receiving the vehicle speed signal and steering signal and reading the opening control signal of the orifice 10 from the predetermined storage area A of the storage element 15a corresponding to the combination thereof. The vehicle speed signal is input to the microcomputer 15 via the buffer 16, and the steering angle signal is input to the microcomputer 15 via the A / D converter 17. In this embodiment, the storage element 15a
A plurality of types of tables corresponding to the difference in external conditions are prepared, and a selection signal that can be operated from the outside is used to input a selection signal via the buffer 16 to switch to a desired table. It is supposed to be. FIG. 4 is a flow chart showing the process of selecting a table and reading the table data in the microcomputer 15.

The opening degree control signal read from the storage element 15a by the access circuit section 15b is input to the driving circuit 18, and the driving circuit 18 is driven by an amount proportional to the magnitude of the opening degree control signal to drive the orifice 10 of the orifice 10. Actuator 10a that adjusts the opening operates. The opening control signal is a signal corresponding to the number of steps when the actuator 10a is a stepping motor, and a current value when the actuator 10a is a solenoid.

In this embodiment, the vehicle speed and the steering angle are selected as external elements related to the steering force, and these values and the orifice opening control amount are tabulated. However, another element is added as an external element. Of course, the table may be set to have three dimensions or more.

FIGS. 5 to 7 show another embodiment of the invention, and the entire system of the steering force control device is the same as that shown in FIG. 1 and is therefore omitted here. The same reference numerals as those in FIG. 1 will be used in the following for the same reference numerals of the respective components.

FIG. 5 is a block diagram showing a schematic configuration of the control circuit 11 for outputting the opening control signal of the orifice 10. In the storage element 15a of the microcomputer 15, a vehicle speed signal and a vehicle speed signal are output as shown in FIG. The relationship between each value of the steering angle signal and the corresponding orifice opening control amount corresponding to the steering force is stored as a table.

The processing in the micro computer 15 is shown in FIG.
This is performed as shown in the flow chart in (b).

The steering center, which is equivalent to when the vehicle goes straight, does not necessarily correspond to the zero position of the actual steering angle, and various driving conditions (road bending, road surface conditions, occupant conditions, loading conditions, etc.) Quantity, vehicle speed, etc.), the program of the above-mentioned microcomputer 15 uses the statistical average value of the steering angle signal θ _t and the steering angle signal input as shown in FIG. 6 (b). The absolute value of the difference is calculated, and the corresponding storage area of the storage element 15a is accessed based on the steering angle signal θ corrected in this way.

The calculation of the statistical average value of the steering angle signal is not always performed, but the input steering angle signal θ _t is shown in the table of FIG. It is performed only in a specific period in the area indicated by. When driving a vehicle, the steering angle becomes smaller as the vehicle speed becomes higher. The area is set to decrease as the vehicle speed increases.

Further, in the calculation of the steering angle signal, the upper limit value θ ₂ and the lower limit value θ ₁ are set to the statistical average value, and when the calculation result exceeds the upper limit value θ ₂ , the average value is set to θ _2. Further, when the value is below the lower limit value θ ₁ , the average value is set to θ ₁ .

The orifice opening control signal read from the storage element 15a is input to the drive circuit 18 as in the case of the above-described embodiment of the invention, and the drive circuit 18 operates in an amount proportional to the magnitude of the opening control signal. The actuator 10a which drives and operates the opening of the orifice 10 operates.

It is needless to say that the calculation of the statistical average value is not limited to the above example and may be performed by other calculation method.

Advantageous Effects of Invention The steering force control device for an electronically controlled power steering according to the present invention, by replacing the table of the storage means,
Alternatively, by preparing multiple types of tables and selecting one from them, it is possible to quickly design in response to changes in various external factors such as the running state of the vehicle and steering conditions, and standardize the control circuit. Therefore, the cost and the development period can be shortened.

In addition, the steering force control device for an electronically controlled power steering according to the present invention can detect the steering angle based on the time when the vehicle goes straight, because of the presence of the steering angle signal correction means, and thus the steering angle control device can be used in various driving conditions. As a result, it is possible to obtain the effect that the steering force that corresponds to the steering angle can be obtained.

Moreover, it is possible to obtain an appropriate steering force according to changes in various external elements such as the running state and steering conditions of the vehicle, and it is possible to quickly respond to the above external elements in the design and standardize the control circuit. Is possible.

Further, according to the present invention, it is possible to obtain the relative steering angle necessary for controlling the power steering. In other words, the steering center corresponding to when the vehicle travels straight does not necessarily correspond to the zero position of the actual steering angle, and various driving states (road bending, road surface condition, occupant condition, load capacity, speed) Etc.), the steering angle signal is sampled for a specific time, and its average value is expressed by the following equation using the steering angle signal θ _t .

Then, this value is set as the zero position of the steering angle, and the absolute value of the difference between the steering angle signal θ _t and the average value set to the zero position θ = | θ _t − |, that is, the relative steering angle is It is something you can ask for. Therefore, in general,
Although it is difficult to adjust and set the absolute mechanical rudder angle center in a vehicle, the adjustment can be made unnecessary by using the relative rudder angle in the present invention.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention, FIG. 2 is a block diagram of its control circuit, FIG. 3 is a diagram showing a two-dimensional example of a table stored in a storage element, and FIG. FIG. 5 is a flow chart showing the control logic of the microcomputer, FIG. 5 is a block diagram of the control circuit of another embodiment of the present invention, and FIGS. 6 (a) and 6 (b) are the control logic of the microcomputer. FIG. 7 is a flowchart showing a two-dimensional example of the table stored in the storage element. 1 ... Rack cylinder, 2 ... Control valve, 3
…… Main pump, 4 …… Engine, 5 …… Pulley, 6
…… Tank, 7 …… Sub pump, 8 …… Hydraulic reaction force chamber, 9
…… Handle shaft (input shaft), 10 …… Olyphus, 10
a ... actuator, 11 ... control circuit, 12 ... vehicle speed sensor (detection means), 13 ... transmission, 14 ... steering angle sensor (detection means), 15 ... microcomputer, 15a ... storage element , 15b ……
Access circuit part, 18 ... Driving circuit

Claims (2)

[Claims] 1. A steering force control device for a power steering, wherein a steering force is changed by controlling an opening of an orifice in a hydraulic circuit, and actuator driving means for driving an actuator of the orifice.
A specific value given to each element as a set of a plurality of external elements, at least one of which is a steering angle, related to the change of the steering force, and an opening degree control amount of the orifice corresponding to the steering force corresponding to the specific value. Is stored as a table, a plurality of detecting means for detecting the values of the plurality of external elements, and a steering angle signal output from one of the plurality of detecting means is sampled for a specific time. Take the average value,
Steering angle signal correction means for setting this value as the zero position of the steering angle and for obtaining the absolute value of the difference between the steering angle signal from one of the plurality of detection means and the average value determined as the zero position. And an orifice opening control signal is read from the corresponding area of the storage means on the basis of the output of the detection means corresponding to external elements other than the steering angle and the output of the steering angle signal correction means, and this is read out to the actuator drive means. A steering force control device for an electronically controlled power steering, comprising: an access unit for inputting. 2. The equivalent spring constant between the input shaft and the output shaft is controlled by the reaction force of the hydraulic reaction chamber to change the relative displacement of the input shaft and the output shaft that determines the opening of the control valve. In a steering force control device for a power steering in which the steering force is changed thereby, an actuator drive means for adjusting and driving an opening of an orifice in a hydraulic circuit for supplying a pressure liquid to the reaction chamber, and the steering force. The relationship between the specific value given to each element as a set of a plurality of external elements, at least one of which is the steering angle, and the corresponding opening degree control amount of the orifice corresponding to the steering force. A storage unit that stores the data as a table, a plurality of detection units that detect the values of the plurality of external elements, and a steering angle signal output by one of the plurality of detection units is sampled for a specific time and its average value is sampled. And A steering angle signal correction that determines this value as the zero position of the steering angle and also obtains the absolute value of the difference between the steering angle signal from one of the plurality of detecting means and the average value set to the zero position. Means and an output of the detection means corresponding to an external element other than the steering angle and an output of the steering angle signal correction means, an orifice opening control signal is read out from a corresponding storage area of the storage means, and this is read out by the actuator driving means. A steering force control device for electronically controlled power steering, comprising: