JPH01114574A - Electric power steering controller - Google Patents

Abstract

PURPOSE:To obtain good responsiveness and a comfortable steering-feeling by correcting an auxiliary steering effort, which is determined based on a torque-sensor output, by means of output signals from both steering wheel turning speed and vehicle speed, thereby producing auxiliary steering effort that corresponds to the running speed of the vehicle. CONSTITUTION:When torque is applied to a steering shaft 2 after turning of a steering wheel 1, a detection signal Ts is output from a torque sensor 7. Based on this output signal Ts, a motor control signal Mb that corresponds to the steering torque is determined by an auxiliary steering effort determining means 11. On the other hand, based on both a detection signal Vs from a vehicle speed sensor 8 and a detection signal Td from a steering-wheel turning speed sensor 9, an auxiliary steering effort correction table 12 is searched for in order to determine a correction coefficient Kma, which corresponds to the steering operational condition. Next, the motor control signal Mb corresponding to the steering torque is multiplied by the correction coefficient Kma by means of a computing element 13, and the result is output to a motor driving circuit 14. By obtaining appropriate auxiliary steering effort from the motor 6 like this, the influence of both inertia and friction of a motor or in a speed reducing mechanism, which varies in correspondence to the steering speed, can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a power steering control system for an automobile that generates an appropriate auxiliary steering force according to the steering force of the steering wheel, for example, and realizes a good steering feeling. It is something.

Conventional technology Conventionally, electric power steering $Jfl devices detect the steering torque applied to the steering shaft during steering operation, control the electric motor based on the output signal of this torque sensor, and generate auxiliary steering force. A method for reducing the steering force is known. However, since the auxiliary steering force generated by the electric motor is transmitted to the steering shaft via the speed reduction mechanism, there is a delay due to inertia and friction of the electric motor and speed reduction mechanism, resulting in a poor steering feel. Therefore, "Special Application No. 169270-1980"
0, differentially compensate the torque sensor output signal,
Special application No. 144784/1984! A method has been devised to improve the responsiveness of an electric power steering control device by differentially compensating a motor control signal, as described in the 1g book.

Problems to be Solved by the Invention However, the influence of the inertia of the electric motor and deceleration mechanism differs depending on the steering speed, and the differential compensation value does not correspond to the vehicle speed. Difficult to empower. As a result, when the driver turns the steering wheel, the steering feels heavy at first, and immediately after steering is stopped, the driver is likely to be pulled by the steering wheel, which is an unfavorable characteristic in terms of steering sensation.

Means for Solving the Problems The present invention eliminates the above-mentioned drawbacks of the conventional art, and provides a correction coefficient table determined by the steering speed sensor output signal and the vehicle speed sensor output signal, and uses this correction coefficient as a torque By multiplying the auxiliary steering force determined based on the sensor output signal to obtain the motor control amount, responsiveness is improved and a good steering feeling is provided.

According to the above configuration, the present invention provides an electric motor that changes according to the steering speed by correcting the auxiliary steering force determined based on the torque sensor output signal with the steering speed sensor output signal and the vehicle speed sensor output signal. It eliminates the effects of inertia and friction of the deceleration mechanism and generates an auxiliary steering force that corresponds to the vehicle's running speed, providing good responsiveness and a light steering feel at low speeds and a stable steering feel at high speeds.

Example An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the basic configuration of the present invention. 1 is a steering wheel, 2 is a steering shaft, 3 is a steering gear, and 4 is a wheel. An electric motor 6 is connected to the steering shaft 2 via a speed reduction device 5, and by driving the electric motor 6, an auxiliary steering force is generated. 7 is a torque sensor attached to the steering shaft;
An output corresponding to the steering force of the steering wheel l can be obtained.

8 is a vehicle speed sensor that outputs a vehicle speed signal according to the vehicle speed based on the rotation speed of the output side of the vehicle's transmission; 9 is a steering speed sensor that outputs a signal according to the steering wheel turning speed; installed. 10
is an electric power steering control device of the present invention,
Microcomputer, RAM (random access)
memory).

Converts the outputs of the auxiliary steering force determining means 11, the auxiliary steering force correction coefficient table 12, a ROM (read only memory) storing a processing program, the torque sensor 7, the vehicle speed sensor 8, and the turning speed sensor 9 into digital values. Analog-to-digital converter (A/D converter) and electric! 116
A motor drive circuit 14 for driving the motor is included. The electric power steering control device 10 includes a torque sensor 7,
The electric motor control amount is determined based on information from the vehicle speed sensor 8 and the steering speed sensor 9, and the electric motor 6 is controlled.

FIG. 2 shows a table of the auxiliary steering force correction coefficient Kma, which shows the representative value Vsi (i=o, 1
, 2...) and the representative value Td of the steering speed sensor output signal
K ma i denoted by J (j: 0.l, 2...)
It is stored as j. Actual vehicle speed Vs and steering speed Td are respectively Vs(i)≦Vs<Vs(i+1)Td(j)
If ≦rd<Td(j+1), then Km
a(ij), Kma(i j+D, Kma(i
Kma is obtained by linear interpolation from four values: +1 j) and Kma (i+1 j+1).

FIG. 3 is a characteristic diagram showing an example of the relationship between the torque sensor output signal Ts and the motor control signal Mb.

Note that the characteristics shown in FIG. 3 are just one example, and can be arbitrarily changed depending on the type of vehicle, etc.

FIG. 4 is a block diagram. When the steering wheel 1 is steered and torque is applied to the steering shaft 2, the torque sensor 7 outputs a detection signal Ts. Based on this, the motor control signal Mb corresponding to the steering torque is determined in the auxiliary steering force determining means 11 having the characteristics shown in FIG. On the other hand, the auxiliary steering force correction coefficient table 12 shown in FIG. decide. Furthermore, in the computing unit 13, the motor control signal Mb corresponding to the steering torque is multiplied by the correction coefficient Kma, and the motor drive circuit 1
Output to 4. In this way, appropriate auxiliary steering force can be applied to the electric W6.
Get from.

Effects of the Invention As described above, the present invention provides a correction coefficient table determined by the vehicle speed sensor output signal and the steering speed sensor output signal,
By multiplying the auxiliary steering force determined based on the torque sensor output signal by a correction coefficient to obtain the electric motor control force, the effects of inertia and friction of the electric motor and deceleration mechanism that change depending on the steering speed are removed, and the It generates an auxiliary steering force that corresponds to the driving speed, achieving good responsiveness and a light steering feel at low speeds and a stable steering feel at high speeds.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram of the electric power steering control VS device of the present invention, and Fig. 2 is an auxiliary and steering force correction coefficient Kn+a.
FIG. 3 is a characteristic diagram showing an example of the relationship between the torque sensor output signal and the motor control signal, and FIG. 4 is a block diagram of the same device. 1... Steering wheel, 2...
Steering shaft, 3...Steering gear, 4
...Wheels, 5...Deceleration gear, 6...
...Electric motor, 7...Torque sensor, 8...
...Vehicle speed sensor, 9...Steering speed sensor, 1
0...Electric power steering control device, 1
1... Auxiliary steering force determining means, 12...
Auxiliary steering force correction coefficient table, 13... Computing machine, 14... Electric! lJ machine drive circuit. Name of agent: Patent attorney Toshio Nakao (1 person) Figure 1 Figure 2

Claims (1)

[Claims] In an electric power steering control device that controls an electric motor and generates auxiliary steering force in the steering system based on the detection output of a torque sensor that detects the steering force, the steering system detects the steering speed. In addition to adding a speed sensor and a vehicle speed sensor that detects the running speed of the vehicle, a correction coefficient table determined by the steering speed sensor output signal and the vehicle speed sensor output signal is provided, and the auxiliary correction coefficient table determined based on the torque sensor output signal is provided. An electric power steering control device characterized in that an electric motor control amount is determined by multiplying a steering force by the above correction coefficient.