JPH02208165A - Control device for electrically-operated power steering device - Google Patents

Abstract

PURPOSE:To enable prevention of a delay in a phase of signal transmission and the generation of self-exciting vibration during steering without driving by a method wherein a phase advancing compensating means which adds a signal proportioning a differentiating value of an input signal to an input signal is mounted between an output torque value indication function part and a control circuit. CONSTITUTION:A second phase compensating part 81 outputs a signal proportioning a differentiating value of an output signal represented by an addition signal of an assist direction motor current command value (i) or an assist direction motor current command valve (i) and a phase motor current command ip and an addition circuit 82 adds a signal, outputted from the compensating part 81, to an input signal. A phase advance compensating means 8 formed with a second phase compensating part and the addition circuit is provided between an output torque value indication function part 2 and a control circuit 5. This constitution not only enables prevention of worsening of response during steering due to a delay in a phase of signal transmission and the influence of inertia of an electric motor 6 by means of first and second phase compensating parts 3 and 81 but also permits prevention of the generation of self- exciting vibration during steering without driving.

Description

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

Conventional technology In an automobile, in order to reduce steering wheel operation during steering, an assist direction motor current instruction section of an assist direction motor current instruction unit that issues an assist direction motor current command value based on a torsional torque signal of a steering shaft during steering operation is used. A phase compensator is provided which drives a control circuit that performs power assist control by the electric motor using a motor current command value, and which emits a signal proportional to the differential value of the torsional torque signal of the steering shaft, and the signal of the phase compensator is Either adding it to the torsional torque signal of the steering shaft, or adding it to the assist direction motor current command value via a phase compensation instruction function section that issues a phase compensation current command value based on the signal of the phase compensation section. A control device for an electric power steering device for automobiles that performs both of these functions has been developed by the applicant and has already been published (Japanese Patent Application Laid-Open No. 61
-1.15771).

Problems to be Solved by the Invention In the conventional device as described above, only a primary phase compensation section for torsional torque signals is provided, so compensation for phase delays in signal transmission, etc. is insufficient, resulting in vibrations in the steering system and deterioration in responsiveness. There is a risk of inviting

The present invention aims to address such problems.

Means for Solving the Problems The present invention provides an output torque value instruction function unit that generates an assist direction motor current command value based on the torsional torque signal of a torsional torque sensor that detects the torsional torque of a steering shaft and generates a torsional torque signal. A first phase compensator is provided which drives a control circuit that performs power assist control to the steering mechanism by the electric motor using the assist direction motor current command value, and which emits a signal proportional to the differential value of the torsional torque signal of the steering shaft. , a phase compensation instruction function section that adds the signal of the first phase compensation section to the torsional torque signal of the steering shaft or generates a phase compensation motor current command value based on the signal of the first phase compensation section; In an electric power steering device that performs one or both of adding a current command value to the assist direction motor current command value, the assist direction motor current command value is added between the output torque value instruction function section and the control circuit. A signal proportional to the differential value of the input signal represented by the directional motor current command value or the addition signal of the assist direction motor current command value and the phase compensation motor current command value is obtained and the requested signal is added to the input signal. This device is characterized by being provided with phase lead compensation means.

By adopting the above configuration, the present invention not only prevents the deterioration of responsiveness due to the inertia of the electric motor, but also prevents the occurrence of automatic vibration during stationary steering, and improves the responsiveness of puff assist. obtain.

Implementation example Embodiments of the present invention will be described below with reference to the accompanying drawings.

In the figure, l is a torsional torque sensor 2 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.
3 is an output torque value indicating function unit which generates an assist direction motor current command value i based on a function as shown in FIG. 3 based on the torsional torque signal of the torsional torque sensor l; A first phase compensator that generates a signal proportional to the differential value adds the signal of the first phase compensator 3 to the torsional torque signal, or adds the signal of the first phase compensator 3 to the torsional torque signal as shown in FIG. The phase compensation motor current command value ip of the phase compensation instruction function unit 4 that issues a phase compensation motor current command value ip that changes continuously when it is less than a predetermined value and becomes a constant value when it is more than a predetermined value is used as the output torque. Drive the electric motor 6 via the control circuit 5 with a signal obtained by adding one or both to the assist direction motor current command value i of the value instruction function unit 2,
Power assist is provided to the steering mechanism 7.

The control circuit 5 includes a positive/negative determining section 51 that determines whether the assist direction motor current command value i or the addition signal of the assist direction motor current command value i and the phase compensation motor current command value 1p is positive or negative; The absolute value converter 53 takes the absolute value 1i1 of the command value l or the absolute value 1i+ipl of the addition signal, and the signal from the positive/negative discriminator 51 determines the rotational direction of the electric motor 6, and also determines the current command of the absolute value converter 53. Duty control is performed by comparing the armature current of the electric motor 6 detected by the armature current detection unit 55 and the current command value of the absolute value conversion unit 53 with the electric motor drive unit 52 that drives the electric motor 6 based on the current value. Duty control unit 5 that performs
It is composed of 4.

As described above, power assist control is performed on the steering mechanism by the electric motor using the assist direction motor current command value I of the output torque value instruction function unit 2 which issues the assist direction motor current command value i based on the torsional torque signal of the steering shaft. The signal from the first phase compensator 3, which generates a signal proportional to the differential value of the torsional torque signal of the steering shaft, is added to the torsional torque signal of the steering shaft, or the first Adding the phase compensation motor current command value ip of the phase compensation instruction function unit 4 which issues the phase compensation motor current command value ip based on the signal of the phase compensation unit 3 to the assist direction motor current command value i; or In an electric power steering device that performs both functions, the present invention provides an electric power steering system that provides the assist direction motor current command value i or the assist direction motor current command value between the output torque value instruction function section 2 and the control circuit 5. A second phase compensator 81 generates a signal proportional to the differential value of the input signal represented by the sum signal of i and the phase compensation motor current command value fp, and the signal emitted from the second phase compensator 81 is used as the input signal. A phase lead compensating means 8 consisting of an adder circuit 82 for adding to .

By adopting the above configuration, the present invention prevents deterioration of responsiveness during steering due to phase delay in signal transmission and the influence of inertia of the electric motor 6 in the first phase compensation section 3 and the second phase compensation section 81. Not only can this be prevented, but also self-excited vibrations during stationary steering can be prevented.

Effects of the Invention As described above, according to the present invention, the output torque value instruction function unit generates the assist direction motor current command value based on the torsional torque signal of the torsional torque sensor that detects the torsional torque of the steering shaft and generates the torsional torque signal. a first phase compensator that drives a control circuit that performs power assist control to the steering mechanism by the electric motor using the assist direction motor current command value, and emits a signal that is proportional to a differential value of the torsional torque signal of the steering shaft; and the first
Adding the signal of the phase compensation section to the torsional torque signal of the steering shaft, or adding the phase compensation motor current command value of the phase compensation instruction function section that issues the phase compensation motor current command value based on the signal of the first phase compensation section. In the electric power steering device that performs either or both of adding to the assist direction motor current command value, between the output torque value instruction function section and the control circuit,
A signal proportional to the differential value of the input signal represented by the assist direction motor current command value or the addition signal of the assist direction motor current command value and the phase compensation motor current command value is obtained and the requested signal is applied to the input signal. By providing an additive phase lead compensation means, it is possible to not only prevent phase delays in signal transmission and deterioration of responsiveness due to inertia of the electric motor, but also to prevent automatic vibrations during stationary steering, and to improve power assist. This can improve responsiveness, and together with the simple configuration, can bring about great practical effects.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing one implementation of the present invention, Figure 2 is a torsional torque signal characteristic diagram, Figure 3 is an assist direction motor current command value characteristic diagram, and Figure 4 is a phase compensation motor current command value characteristic diagram. It is. l... Torsional torque sensor, 2... Output torque value instruction function section, 3... First phase compensation section, 4... Phase compensation instruction function section, 5... Control circuit, 6... electric motor, 7
... Steering mechanism, 8... Phase lead compensation means, 81...
- Second phase compensation section, 82... addition circuit. that's all

Claims (1)

[Claims] The electric motor is driven by the assist direction motor current command value of the output torque value instruction function section which issues the assist direction motor current command value based on the torsional torque signal of the torsional torque sensor which detects the torsional torque of the steering shaft and issues the torsional torque signal. A first phase compensator is provided that drives a control circuit that performs power assist control on the steering mechanism and also generates a signal proportional to the differential value of the torsional torque signal of the steering shaft, and the signal of the first phase compensator is The phase compensation motor current command value of the phase compensation instruction function section that generates the phase compensation motor current command value by adding it to the torsional torque signal of the steering shaft or based on the signal of the first phase compensation section is added to the assist direction motor current command value. In the electric power steering device, the assist direction motor current command value or the assist direction motor current is connected between the output torque value instruction function section and the control circuit. A phase lead compensation means is provided for determining a signal proportional to the differential value of the input signal represented by the addition signal of the command value and the phase compensation motor current command value, and adding the determined signal to the input signal. A control device for an electric power steering device.