JPH0342235B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a control device for an electric power steering device for an automobile.

BACKGROUND TECHNOLOGY In order to reduce the need for steering wheel operations during steering in automobiles, a torque sensor is provided to detect steering torque during steering operations, and the steering torque detected by the torque sensor is converted into an electrical quantity. Electric power steering devices have already been developed in which the output of an electric motor is variably controlled according to changes in the amount of electricity, and the electric motor provides power assist in the steering direction according to the steering torque. (For example, see Japanese Patent Publication No. 45-41246).

Problems to be Solved by the Invention The electric power steering device as described above is
Due to phase lag in the electric circuit, etc., a time delay occurs between when the torque sensor detects the steering torque and when the electric motor generates power assist. In this case, the steering system becomes vulnerable to disturbances, and there is a problem that self-excited vibrations are likely to occur during stationary steering, and since the electric motor provides power assist to the steering mechanism via a reduction gear, There is a problem in that the responsiveness of the steering wheel deteriorates due to the inertia of the electric motor, the friction of the speed reducer, etc.

It is an object of the present invention to solve the problems of the electric power steering device as described above and to improve the steering feeling.

Means for Solving the Problems The present invention provides an electric power steering device that performs power assist for steering using the output of an electric motor. , a phase compensator that emits a signal proportional to the differential value of the torsional torque signal of the torsional torque sensor;
a phase compensation instruction function section that issues a phase compensation current command value based on the signal of the phase compensation section; The first feature is that a control circuit is provided for controlling the current value supplied to the electric motor based on the added value of the assist direction motor current command value and the phase compensation current command value of the phase compensation instruction function section, An assist direction motor current command value is determined based on the signal obtained by adding the phase compensation section signal to the torsion torque signal, and the supply current to the electric motor is determined based on the added value of the assist direction motor current command value and the phase compensation current command value. The second feature is that it is controlled.

By adopting the above configuration, the present invention not only improves the followability of power assist by the electric motor, but also prevents the generation of self-excited vibration during stationary operation and absorbs the influence of the inertial force of the electric motor. It is something that can be measured.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes an assist direction motor current indicating section, which includes a torsional torque sensor 11 that detects the torsional torque of the steering shaft and emits a torsional torque signal VT proportional to the torsional torque as shown in FIG. and an output torque value indicating function section 12 which issues an assist direction motor current command value i based on a function as shown in FIG.

Reference numeral 2 denotes a phase compensator which generates a signal proportional to the differential value of the torsional torque signal of the torsional torque sensor 11, and the signal of the phase compensator 2 is added to the torsional torque signal and is added to the torsional torque signal as shown in FIG. The phase compensation current command value ip of the phase compensation instruction function section 21 which continuously changes when the signal of the phase compensation section 2 is below a predetermined value and issues a constant value phase compensation current command value ip when the signal is above a predetermined value. The electric motor 4 is driven via the control circuit 3 with the added value added to the assist direction motor current command value i of the output torque value instruction function section 12, and power assist is given to the steering mechanism 5.

The control circuit 3 includes a positive/negative determining unit 31 that determines whether the added value of the assist direction motor current command value i and the phase compensation current command value ip is positive or negative, and an absolute value converter that takes the absolute value |i+ip| of the added value. 33, an electric motor drive unit 32 that determines the rotation direction of the electric motor based on the signal from the positive/negative discrimination unit 31 and drives the electric motor based on the current command value of the absolute value conversion unit 33;
It consists of a duty control section 34 that performs duty control by comparing the armature current of the electric motor detected by the armature current detection section 35 with the current command value of the absolute value conversion section 33.

As described above, in the present invention, the phase compensator 2 obtains a signal proportional to the differential value of the torsional torque signal of the steering shaft, and the assist direction motor current command value is determined based on the addition signal of this signal and the torsional torque signal. The control circuit 3 is controlled by the added value obtained by adding the phase compensation current command value which changes continuously when the output signal of the phase compensation section 2 is below a predetermined value and becomes a constant value when it is above the predetermined value. This not only improves the followability of the electric motor's power assist, but also prevents the occurrence of self-excited vibrations when stationary and absorbs the influence of the electric motor's inertial force when driving at high speeds, making it possible to improve the performance during steering. It can remove discomfort.

In the above embodiment, the torsional torque sensor 1
The output torque value instruction function section 12 calculates an assist direction motor current command value based on the added value of the torsional torque signal of No. 1 and the output signal of the phase compensation section 2, and further calculates the assist direction motor current command value and the phase compensation instruction function section. Although an example has been given in which the control circuit 3 is controlled by the added value obtained by adding the phase compensation current command value of 21, the configuration for adding the output signal of the phase compensation section 2 to the torsion torque signal may be omitted in some cases. , so that the control circuit 3 is controlled only by the added value of the assist direction motor current command value i obtained by the output torque value instruction function section 12 based on the torsion torque signal and the phase compensation current command value ip of the phase compensation instruction function section 21. You can also do this.

Effects of the Invention The present invention provides an assist direction motor current command value of an assist direction motor current instruction section that issues an assist direction motor current command value based on a torsional torque signal of a torsional torque sensor, and a phase compensation current command value of a phase compensation instruction function section. or the assist direction motor current command value of an assist direction motor current instruction unit that issues an assist direction motor current command value based on the addition signal obtained by adding the signal of the phase compensation unit to the torsional torque signal of the torsional torque sensor; Since a control circuit is provided to control the current value supplied to the electric motor based on one of the deviations of the added value from the phase compensation current command value of the phase compensation instruction function section, power generation due to delay in signal transmission in the electric circuit is provided. In addition to improving the followability of the assist, it also prevents the occurrence of self-excited vibration during stationary cutting operations.
This can eliminate the uncomfortable feeling during steering caused by the inertial force of the electric motor when driving at high speeds, and can have a great practical effect.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a torsional torque signal characteristic diagram, Fig. 3 is an assist direction motor current command characteristic diagram, and Fig. 4 is a phase compensation current command value characteristic diagram. . DESCRIPTION OF SYMBOLS 1... Assist direction motor current instruction part, 11... Torsional torque sensor, 12... Output torque value instruction function part, 2... Phase compensation part, 21... Phase compensation instruction function part, 3... Control circuit, 4... Electric motor, 5... Steering mechanism.

Claims (1)

[Scope of Claims] 1. In an electric power steering device that performs power assist for steering using the output of an electric motor, there is provided a torsional torque sensor that detects torsional torque of a steering shaft and generates a torsional torque signal, and the torsional torque sensor. A phase compensation unit that generates a signal proportional to the differential value of the torsional torque signal of the torsional torque sensor and a phase compensation instruction function unit that generates a phase compensation current command value based on the signal of the phase compensation unit are provided, and the torsional torque signal of the torsional torque sensor is provided. Supply current to the electric motor based on the sum of the assist direction motor current command value of the assist direction motor current command value of the assist direction motor current instruction section that issues the assist direction motor current command value based on the phase compensation instruction function section and the phase compensation current command value of the phase compensation instruction function section. A control device for an electric power steering device, characterized in that a control circuit for controlling a value is provided. 2. In an electric power steering device that performs power assist for steering using the output of an electric motor, a torsional torque sensor that detects the torsional torque of the steering shaft and generates a torsional torque signal, and differentiation of the torsional torque signal of the torsional torque sensor A phase compensator that emits a signal proportional to the torsional torque sensor and a phase compensation instruction function unit that emits a phase compensation current command value based on the signal of the phase compensator are provided, and the signal of the phase compensator is added to the torsional torque signal of the torsional torque sensor. Based on the added value of the assist direction motor current command value of the assist direction motor current instruction section that issues the assist direction motor current command value based on the addition signal obtained by adding , and the phase compensation current command value of the phase compensation instruction function section, 1. A control device for an electric power steering device, comprising a control circuit for controlling a current value supplied to an electric motor.