JPS62152968A - Electrical power steering controller - Google Patents

Abstract

PURPOSE:To easily adjust a torque sensor and a steering angle sensor to the neutral points thereof in a short time, by using a variable resistor and so forth in a controller to electrically set the sensors at the neutral points. CONSTITUTION:When a steering wheel 1 is rotated, tires 6 are steered through a rack 4, a pinion 5 and so forth. At that time, a steering force is detected by a torque sensor 2 whose output signal is entered into a controller 8 together with the output signal of a steering sensor 11 to regulate the drive of an electric motor 7 which serves to apply a steering assistant force. When the torque sensors 2 is to be adjusted to the neutral point thereof, a vehicle is put in a state of straight movement to make the steering force on the steering wheel zero, the output from the torque sensor and a torque neutral adjustment signal are then compared with each other by the controller 8 and the variable resistor (not shown in the drawing) of a neutral adjustment circuit is thereafter adjusted until the output and the signal coincide with each other and a neutral point indicator LT is lit. When the steering angle sensor 11 is to be adjusted to the neutral point thereof, the same operation as the adjustment of the torque sensor to the neutral point thereof is performed.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an electric power steering control device,
In particular, it is an object of the present invention to provide a suitable control device that improves the deterioration in feeling caused by errors in the neutral points of the torque sensor and the steering angle sensor.

[Background of the invention]

The conventional electric power steering control device was developed in Japanese Patent Application Laid-open No. 59
-171759, the voltage value representing the neutral point of the torque sensor and steering angle sensor (or.

resistance value, current value). No consideration was given to the means of converting the mechanical neutral point into an electrical position.
When actually installing it in a product, there was a problem that it took time to make adjustments.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric power steering control device that improves the matching between a torque sensor and a steering angle sensor attached to a vehicle and a control device.

[Summary of the invention]

The present invention is characterized in that the neutral point of the sensor of the electric power steering device can be easily set by electrically setting the mechanical neutral point of the torque sensor and the steering angle sensor on the control device side. [Embodiment of the Invention] An embodiment of the present invention will be explained below with reference to FIG. When the driver applies steering force to the steering wheel 1, the torque sensor 2
In this step, the steering force transmitted to the shaft 3 is detected. This can be accomplished by inserting a strain gauge or a torsion spring mechanism into the shaft 3, and detecting the amount of deflection of this spring using a volume or the like. This steering force is transmitted to the tires 6 via the rack 4 and pinion 5, and the tires 6 are thereby operated. The coefficient of friction of the tires 6 is extremely large when the vehicle speed is low. This separation is necessary when parking in a garage, parallel parking, etc. This force is assisted by the electric motor 7, which applies the voltage of the battery 9 from the control device 8 to the electric motor 7 based on the output obtained from the torque sensor 2, and controls its current value. This current value also changes depending on the vehicle speed and steering angle sensor. The speed reducer 10 amplifies the assist force of the electric motor 7. FIG. 2 shows a block diagram of the above control. The steering angle sensor 11 detects the deviation angle of the tire from the straight-ahead position.

The output of the torque sensor 2 is input to a function generator 12.

This function generator 12 has characteristics as shown in FIG. That is, the function generator determines a command current (assist force) for the output (steering force) of the torque sensor. Further, the command current is corrected based on the vehicle speed. That is, at high speeds, the steering force is increased to provide the special characteristics indicated by the dotted line in FIG. 3 in order to obtain stable operability.

On the other hand, the output of the torque sensor is input to a differentiating circuit 13, and the output is added to the output of the function generator 12. This is the amount of current added to remove the inertia of the motor. This added value is corrected by the output of the steering angle sensor so that the vehicle returns to the straight direction.

This correction is independent of the steering force, and even if there is no steering force, if the tires are deviated from the straight-ahead position, current is applied to the electric motor 7 to return them to the straight-ahead position.

This calculation is performed by the steering angle correction circuit 14. The added or subtracted value is determined to be positive or negative, and if it is positive, the current direction is switched so that it rotates clockwise (or counterclockwise).

With the above control, the torque sensor 2 and the steering angle sensor 11
FIG. 4 shows the configuration of the means for setting the neutral point of , and FIG. 5 shows its control block diagram.

FIG. 6 is an example of the output of the torque sensor.

In other words, when the steering wheel is turned to the right, a right torque is applied to the torque sensor, and the output is proportional to the torque, and the output is A- in the diagram.
It shows characteristics similar to H. In addition, when the handle is operated to the left, the outputs A-C in the figure are shown. The same applies to the steering angle sensor.

FIG. 7 shows an example of a torque neutral adjustment circuit, in which a variable resistor is brought into contact between the stabilizer voltage v0° and the earth GND, and the output voltage can be varied by moving the variable terminal. The same applies to the steering angle neutral circuit, in which a digital switch may be used instead of the variable resistor.

In FIG. 4, a torque sensor output signal, a torque neutral adjustment signal, a steering angle sensor output signal, and a steering angle neutral adjustment signal are connected to the CPU via Ilo of the control device.

If the indicator (for example, a lamp) indicating that the torque and steering angle are neutral is LD, this is also controlled by the CPU.
connected via.

If the sensor output when the torque is neutral is VT (v), and the sensor output when the steering angle is neutral is VD (v), then each neutral signal V
(!? t V (! D, v0=v, T, vD=
All you have to do is adjust the variable resistor so that V is 7, but instead of using a voltmeter or the like, use the neutral point indicator L? , LD allows for easy adjustment.

Next, an example of the adjustment method will be described.

First, the vehicle is set to go straight ahead, and the steering force is applied to the steering wheel at zero. At this time, turn on the control flow shown in Figure 5.
let The CPU reads the torque sensor output and the torque neutral adjustment signal and determines whether they are the same. If they are not the same, the neutral indicator L7 is turned ON. Therefore, the display is ON
Adjust the variable resistor accordingly. At this time, the control device can detect that the sensor output is at the neutral point and can store it. The same applies to the steering angle neutral adjustment. The storage means is to install adjustable variable resistors inside and outside the control device, store them as part of the hardware, or use other methods (RAM, etc.)
You can also memorize it with and remove the adjustable variable resistor.

According to this embodiment, the sensor output voltage V? when torque is neutral due to differences in performance of each vehicle? and the steering angle neutral voltage can be easily adjusted without the need for special measuring instruments, and the adjustment circuit can be made at low cost.

〔Effect of the invention〕

As described above, according to the present invention, an electric power steering control device having a torque and steering angle sensor neutral adjustment function that can perform neutral adjustment of each sensor in a short time can be easily provided.

[Brief explanation of drawings]

Fig. 3 is a torque sensor and command current characteristic diagram of this control device, Fig. 4 is a block diagram showing the system configuration, Fig. 5 is a flow chart of this control device, and Fig. 6 is a torque sensor output characteristic. 7 are torque neutral adjustment circuit diagrams. 1... Handle, 2... Torque sensor, 3... Shaft, 4... Rack, 5... Pinion, 6...
Tire, 7... Electric motor, 8... Control device, 9...
Battery, 1o... Decelerator, 11... Rudder angle sensor,
12...Function generator, 13...Differential circuit, 14...
- Rudder angle correction circuit, 17...Vehicle speed detection circuit, 18...
Rudder angle detection circuit, 19... conduction rate setting circuit.

Claims (1)

[Claims] 1. A torque sensor that detects the steering force of the steering wheel, a torque neutral adjustment circuit, a steering angle sensor that detects the tire position, a steering angle neutral adjustment circuit, an indicator that displays each neutral point, and an assist force In a control device that applies a voltage to the electric motor from a battery to control the flowing current, the torque sensor output signal, the torque adjustment signal, the steering angle sensor output signal, and the steering angle adjustment signal. Converts the mechanical neutral point of the vehicle into an electrical neutral point, detects the neutral point with a microcomputer, performs arithmetic judgment, stores the value, and displays it at the same time to determine the neutral point of the torque sensor and steering angle sensor. An electric power steering control device characterized by: