JPS62168758A - Motor driven power stearing device - Google Patents

Abstract

PURPOSE:To restrain temporarily abrupt change in the rotation of a motor to provide a smooth steering feeling by detecting the rotational speed of the motor for generating auxiliary torque generated by the change in a load and correctively changing a motor controlling signal on the basis of the detecting signal. CONSTITUTION:When a key switch for an ignition key is turned on and a steering wheel is steered, the respective detecting signals of a steering torque detecting means 1 and a steering rotation detecting means 2 are input to a motor controlling signal generating means 4 to determine the motor controlling signal corresponding to armature voltage of a motor 3 from stearing torque and speed. And the controlling signal and the rotational acceleration detecting signal of the motor 3 detected by a rotational acceleration detecting means 5B are input to a motor driving means 5A to controllably drive the motor 3 on the basis of the deviation of both signals from each other. Thus, the abrupt change in the rotation of the motor 3 when the rotational acceleration of the motor 3 is abruptly increased can be restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electric power steering device that generates auxiliary torque using an electromagnetic booster using an electric motor to reduce the steering torque of a steering system.

(Prior Art) In general, an electric power steering device includes a steering force booster using an electric motor as a power source and its control circuit, detects the steering torque applied to the steering wheel, and detects the steering torque applied to the steering wheel based on this detection signal. The steering force is reduced by generating auxiliary torque in the electric motor using the control circuit. In addition, in the case of a control circuit configured with an analog circuit, feedback control is performed using an analog electric signal of the motor, thereby enabling responsive motor control and appropriately improving steering performance.

By the way, power steering devices are required to have high reliability, so it is necessary to have many fault diagnosis functions, and also to have a stable steering feeling, so stable and accurate control without variation is required. Therefore, there are expectations for microcomputer control, which can achieve many functions with a small device. However, due to their characteristics, microcomputers cannot read many inputs at the same time, they lack advanced calculation functions and the processing time is extremely long, and since they operate based on internal clock pulses, it takes a certain amount of time for signal processing. In addition, it is difficult to perform conventional feedback control that repeats the feedback loop as described above many times, and furthermore, steering wheel operation such as a power steering device is difficult for the driver to operate. Conventionally, it has been difficult to stably follow arbitrary movements and to obtain smooth and appropriate steering feel.

In order to solve this problem, the applicant has developed an electric power steering system using a microcomputer.
No. 0-9548" was filed earlier.

According to this prior application, the steering torque and steering rotation speed of the steering system are detected, and an electric motor control signal is determined and output based on both detection signals. Since the control signal can be determined, there is no need to construct a feedback loop that reads the output signal and corrects the current control signal, which can significantly shorten processing time and provide stability to the driver's arbitrary steering wheel operations. This made it possible to follow the instructions.

(Problems to be Solved by the Invention) However, although the above-mentioned conventional electric power steering device configured using a microcomputer has excellent responsiveness, for example, immediately after the vehicle starts, or when there is a sudden change in road surface conditions, etc. If the load changes significantly, as in
The electric motor that generates the auxiliary torque may rotate rapidly or make large changes in rotation, and under these conditions, the steering feel may become mechanical.
It is desirable to have a softer steering feel.

(Object of the Invention) Therefore, the present invention provides a rotational acceleration detection means for the electric motor, and drives the electric motor based on the deviation between detection signals of the motor control signal generation means and the rotational acceleration detection means.
An object of the present invention is to provide an electric power steering device that can temporarily suppress rotational changes of an electric motor when the electric motor suddenly starts up or changes in rotation, and can provide a gentle steering feeling.

(Means for Solving Problems and Their Effects) FIG. 1 shows an overall configuration diagram of the present invention. 1st
In the figure, (1) is a steering torque detection means for detecting the steering torque of the steering system, (2) is a steering rotation detection means for detecting the rotation speed of the steering system, and (3) is a means for detecting the auxiliary torque applied to the steering system. The electric motor that generates (
4) motor control signal generating means (5B) for determining and outputting a control signal for the electric motor (3) based on the detection signals from the steering torque detection stage (1) and the steering rotation detection means (2);
(5A) is based on the deviation between the control signal from the motor control signal generating means (4) and the detection signal from the rotational acceleration detection signal (5B). This is an electric motor driving means for driving the electric motor (3). According to such a device, when the steering wheel is steered after the key switch of the ignition key is turned on to drive the engine, the steering torque detection means (
Based on the steering torque detection signal of 1) and the steering wheel speed detection signal detected by the steering rotation detection means (2), a motor control signal corresponding to the armature voltage of the electric motor (3) is determined, and the motor is controlled. Signal generation means (4
) is output. Furthermore, this control signal and the electric motor (3
) The electric IJjt (3) generates an auxiliary torque in the steering direction and rotates based on the deviation from the rotational acceleration detection signal by the electric motor drive means (5A), thereby reducing the steering force. Therefore, when the rotational acceleration of the electric motor suddenly increases, such as when the electric motor suddenly starts up or changes its rotation, the sudden change in the rotation of the electric motor is suppressed, and a soft steering feeling can be obtained.

(Example) A preferred example of the present invention will be described below based on the drawings.

In Fig. 2, (6) is a case, (7) and (8) are an input shaft and an output shaft that are arranged coaxially with each other.The electric power steering device of this embodiment has an input shaft (7).
is provided integrally with the steering wheel (not shown), while the output shaft (8) is provided with a constant velocity joint, a rack φ pinion, a tie rod, a knuckle, etc., which converts the rotation of the steering wheel into a rocking motion of the wheel, thereby moving the vehicle. This enables the steering of the vehicle.

The inner end of the input shaft (7) is connected to the inner end of the output shaft (8) by a bearing (
9), while their inner ends are connected by a torsion bar (10), and the input shaft (
7) is connected to the bearing (11), and the output shaft (8) is connected to the bearing (12).
) and (13), each of which is rotatably supported.

Furthermore, a steering rotation sensor (14) disposed around the input shaft (7), a steering torque sensor (15) disposed around the fitting portion of the input/output shafts (7), (8), Output shaft (8)
an electric motor (3) disposed approximately parallel to the motor (3), a motor rotation sensor (17) integrally disposed on the rotor (not shown) of the electric motor (3) to detect the rotational speed of the electric motor, and an output shaft (8), the speed reducer (18) and the electromagnetic clutch (19), the vehicle speed sensor (2o), the steering torque sensor (15), and the steering rotation sensor (2o), which are located around the vehicle speedometer. 14) and motor rotation sensor (17)
The configuration includes a control device (21) and a power supply circuit (22) that drive and control the electric motor (3) and the electromagnetic clutch (18) based on detection signals from the electric motor (3) and the electromagnetic clutch (18).

More specifically, the steering rotation sensor (14) includes a pulley (22) integrally provided on the outer periphery of the input shaft (7) and a generator (23) integrally provided in the case (6). A timing bell (25) is wound around a pulley (24) provided integrally with the rotor, and detects the direction and speed of rotation of the input shaft (7).

The steering torque sensor (15) includes a movable iron core (2B) that is displaceable in the axial direction on the outer periphery of the fitting part between the input shaft (7) and the output shaft (8), and a pole on the inner periphery of the case (8). ) (
27) and a coil part (28) which is integrally fixed. The movable iron core (28) is
Bottles (30) protruding from each protrusion (29) protruding from the output shaft (8) at 180° symmetrical positions;
Each projecting piece (31) projecting from the input shaft (7) is provided with elongated holes (33) and (34) that respectively engage with a bottle (32) projecting from the input shaft (7) at an angle of 80 degrees with respect to the input shaft (30). ing. Long hole (
33) is formed along the axial direction, while the elongated hole (34)
is formed to be inclined at a required angle with respect to the axial direction. Therefore, if an angular difference occurs between the input and output shafts (7) and (8), the movable iron core is (26) is moved in the axial direction, and the movable iron core (28) is displaced together with the torsion bar (10) in response to the steering torque applied to the input shaft (7). In addition, a movable iron core (2
The spring (35) provided between the circlip of the bearing (12) and the movable iron core (2) is made of a non-magnetic material.
6) The axial play is removed.

In addition, a coil part (28) provided around the movable core (26) with an appropriate gap is a primary coil into which an AC signal is input, and an output signal corresponding to the displacement of the movable core (26). It consists of a pair of secondary coils that output. Therefore, when an angular difference occurs between the input and output shafts due to twisting of the torsion bar (10), the axial displacement of the movable core (26) differentially changes the output of the pair of secondary coils, resulting in an electrical signal. converted.

Furthermore, a rotary damper (3G) is provided at the fitting portion of the input/output shafts (7) and (8). This damper (3B) has a viscous material sealed in a space sealed around the bearing (8) with seal members (37) and (38), and includes an input/output shaft (7),
(8) A torque proportional to the relative rotational speed is generated.

This is to dampen rotational vibration between the input and output shafts.

The electric motor a (3) is installed in the case (6) almost parallel to the output shaft (8), and a small diameter pulley (39) is installed in the case (6) at one end of the rotor and at the other end. A rotor of a motor rotation sensor (17) consisting of a generator is integrally provided.

The reduction gear 24 (18) includes a large-diameter pulley (41) that is rotated at a reduced speed by a small-diameter pulley (39) of an electric motor (3) via a timing bell (40), and a rotation of this large-diameter pulley (41). Planetary gear mechanism (42) that further decelerates
It consists of The large diameter pulley (41) is the output shaft (8)
and is rotatably supported via a bearing (41A). A sun gear (43) of a planetary gear mechanism (42) is provided inside one end of the large-diameter pulley (41), and a plurality of pinion gears (44) and a pinion gear (45) are externally meshed with this sun gear (43). A planetary gear mechanism (42) is constituted by a carrier (46) that is rotatably supported and also rotates, and a ring gear (47) consisting of an internal gear that internally meshes with a pinion gear (42). A hollow shaft (47) is provided inside the carrier (48), and the left end of this hollow shaft (47) is provided with a tapered screw (4 days) on the outer periphery, a spline (48) on the inner periphery, and a spline (48) in the axial direction. A plurality of slits are provided. Then, by tightening the nut (50), the spline (8a) of the output shaft (8) and the spline of the hollow shaft (47) are fixed, and the carrier (4) which is the output of the planetary gear mechanism (42) is fixed.
6) is transmitted to the output shaft (8).

The ring gear (47) has a 7-lunge-shaped clutch plate (
51) is provided in one body and rotatably fitted into the case (6).

The electromagnetic clutch (19) has a bolt (
a field core (54) housing an electromagnetic coil (53) fixed in one body with a ring gear (47);
) and a disc spring (47a) that presses the clutch plate against the field core (54).

Then, the electromagnetic coil (53) is energized, and the clutch plate (53) is energized.
1) to the case (6) side, the rotation of the sun gear (43) is transmitted to the carrier (4B) at a reduced speed. The field core (54) also has a disc spring (47) that rotatably supports the output shaft (13) via a bearing (13).
A) is for eliminating the gap between the field core (54) and the clutch plate (51), which is an armature, and the pressing force is small.

Next, the control device (21) will be explained based on FIG. 3.

The motor control signal generating means (4) includes a microcomputer unit (55), an A/D converter (58), and a D
/A converter (57), steering torque detection means (1), steering rotation detection means (2), vehicle speed detection means (
5th), each detection signal Sl~ from the current detection means (59)
S6 is input.

The steering torque detection means (1) includes the steering torque sensor (
15) and a microcomputer unit (55) to the second coil (28a) of this steering torque sensor (15).
A drive unit (80) that divides the internal clock pulse T1 and outputs an AC signal, and AC signals obtained from the secondary coils (28b) and (28c) in response to the displacement of the movable iron core (28), respectively. Rectifying circuit (81A)
, (fllB), and low-pass filters (G2A) and (82B) that remove high frequency components, and the respective analog electric signals Sl, S2 are generated by motor control signal generating means (
4) is output to the A/D converter (5B).

The steering rotation detection means (2) includes the steering rotation sensor (14).
)'s generator (23) is grounded, and the other end is a low-pass filter (G3A) that removes noise, (63B
), and an inverting amplifier circuit (84A) and a non-inverting amplifier circuit (134B) for amplifying the absolute value of the output of the generator (23).
The respective analog electric signals S3 and S4 are generated by motor control signal generating means (A/D converter (56)
) is output.

The vehicle speed detection means (58) connects a constant voltage power source to a vehicle speed sensor (20) consisting of, for example, a magnet (65) that rotates together with a speedometer cable and a reed switch (66) that is turned on and off as the magnet (65) rotates. a pulse conversion circuit (87) that supplies the pulse signal and outputs the intermittent signal of the reed switch (B6) as a pulse signal, a low-pass filter (68) that removes noise from this output signal, and a waveform that rectangles this output signal and outputs it. The pulse signal S6 is output to the microcomputer unit (55) of the motor control signal generating means (4).

The microcomputer Φ unit (55) is composed of an I10 board, CPU, ROM, RAM, reference clock, clock generator, etc., and detects the A/D converter (56) or vehicle speed detection means (58) according to the control software described later. Read the signal S6, send the electromagnetic latch control signal T2 to the electromagnetic clutch drive means (70), and send the motor rotation direction control signal T3 and the motor control signal T4 to the A/
Output A4 of the D converter (57) and motor control signal T
5 is output to the motor drive means (5A).

The motor drive means (5A) includes a differential amplifier circuit (7) that differentially amplifies the deviation between the motor control signal A4 and a detection signal A5 from the motor rotational acceleration detection means (5B), which will be described later.
1), a triangular wave generation circuit (72), and a differential amplifier circuit (72).
a comparison circuit (7) that compares and outputs the output signal of 1) with the output signal of the triangular wave generation circuit (72) and converts it into a PWM signal with a duty ratio proportional to the output of the differential amplifier circuit (71);
3) and a programmable circuit that converts the output signal D1 of this comparison circuit (73) and the motor control signal T5 into a PWM signal.
A drive unit (74) to which the output signal D2 of the timer circuit (81) and the motor rotation direction control signal T3 of the motor control signal generating means (4) are input, and FETs (75 to 7).
8). In the bridge circuit, the drain terminals of FETs (75) and (78) are both connected to a power supply (78), and FETs (7B) and
The source terminals of (7?) are both grounded via a current detection resistor (80). Then, the source terminal of FET (75) and the drain terminal of FET (7El) are connected, and this connection and the source terminal (78) of FET (7B) and FE
The connection portion of T (77) with the drain terminal is connected to the electric motor (3). The gate terminal of each FET (75-7) is connected to a drive unit (74), and the motor control signal 〒3 is applied to the FET (75), (77) or FET ( 7
8), (7B) is in a drivable state, and the PW
M signal D1 is FET (77), PIIIN signal D2 is FET
ET (75) or PWM signal DI is FET (7B)
A signal D2 is input to the FET (78) at P, and the rotational direction and power of the electric motor (3) are controlled.

The rotational acceleration detection means (5B) of the electric motor (3) includes a motor rotation sensor (17) consisting of a DC generator, a low-pass filter (81) for removing noise from this rotation sensor,
an amplifier circuit (82) that performs DC amplification, and a differentiation circuit (83) that differentiates this output and outputs it to the differential amplifier circuit (71).
), and when the electric motor (3) rotates, the electric motor (
As the rotational acceleration signal A5 of 3), the electric motor drive means (5A
) is input to the differential amplifier (71).

The electromagnetic clutch drive means (70) is configured to drive the electromagnetic clutch (
19), and a drive unit (85) for controlling the operation of this relay by the electromagnetic clutch control signal T2 of the motor control signal generating means (4).
It is composed of Relay (84) sui.

One end of the chi part is connected to the power supply (78), and the other end is connected to the electromagnetic clutch (1
8), and the other end of the electromagnetic coil (53) is connected to ground.

The current detection means (59) of the motor (3) includes the current detection resistor (80), a low-pass filter (86) that converts the voltage across the resistor (80) into a DC voltage, and an amplifier circuit that amplifies the DC output. (87), and an amplifier circuit (
The current detection signal S5, which is the output of 87), is connected to the A/D converter 6), thereby detecting abnormalities in the motor (3) and the motor drive means (5A).

Next, the action will be explained.

FIG. 4 is a flowchart showing an outline of control processing in the microcomputer unit (55), and PO-PO2 in the figure indicate each step of the flowchart.

When the key switch of the ignition key is turned ON, power is supplied to each circuit and control starts (PO).
(55) Initial settings such as setting the I10 board, clearing RAM data, and setting the timer are performed (PI), then,
Read the detection signal S5 from the current detection means (59),
An initial failure diagnosis is performed to check whether the current value is zero (P2), and if it is not zero, it is diagnosed as a failure and all operations are stopped. If it is zero, read the detection signals Sl and S2 from the steering torque detection means (1) shown in Fig. 5 (P3), and calculate the difference T between si and S2 (P4).
After that, in step P5, a failure diagnosis of the steering torque detection means (1) is performed.

Here, we focus on the fact that the calculated value of (St+S2)/2 is always a constant value, and check whether this value is within a predetermined range. If it is, it is determined that it is normal and the electromagnetic clutch is driven. A clutch control signal, T2, is output to the means (70) to fix the ring gear (47) of the electromagnetic clutch (19) to the case (6) via the clutch plate (51) and the field core (54). Therefore, the power of the electric motor (3) can be transmitted to the output shaft (8) via the reduction gear (18).

Further, if the calculated value of (S1+S2)/2 is not within a predetermined range, it is determined that there is a failure in the steering torque detection means (1), and the electromagnetic clutch (19) is turned off by the control signal T2. Stop all operations. If normal, determine the sign of the steering torque calculation T (PB, P
7) L, check the direction of action of the steering torque. Then, if the sign is negative, the sign flag F is set to 1 (PB), and then absolute value conversion (PB) is performed; if the sign is positive, the sign flag F is
Set 0 to PIO) and proceed to step pH.

At step pH, data DF is extracted from table l (Fig. 6) storing friction data OF of the steering system including the electric motor (3) whose address is the absolute value T of torque.
6 Next, in step P12, table 2 (Fig. 7) is stored that stores auxiliary torque data DT of the electric motor (3) with respect to the road load whose address is the absolute value T of torque.
Further, in order to check the change in torque value, calculate the value Δ by subtracting the previous torque T1 from the current torque T (PI3) L, and determine the sign of this value Δ (PI
3) Do.

If the torque value is increasing, Δ>0, so the return correction data OR is set to zero (PI3), and if the torque value is decreasing, the return correction data DR is taken out from table 3 (PlB). It is expressed as shown in FIG. 8, and stores return correction data DR whose address is the absolute value T of torque. In step P16, processing is performed to set the current torque T to the previous value 〒1.

Next, in step P17, the detection signal S6 of the vehicle speed detection means (58) is read, and its period TV is measured (
PlB), then a vehicle speed coefficient K that reduces the auxiliary torque data DT whose address is period TV according to the vehicle speed.
The vehicle speed coefficient KV is taken out from the table 4 (FIG. 9) storing V and multiplied by the auxiliary torque data DT (P2O). Then, in step P2L, the auxiliary torque D1 of the electric motor (3) is calculated (10th 11), when T=O in step P6, the auxiliary torque D of the electric motor (3)
Set I to zero (P22), set code flag F to zero (P23)
, jump to P24. In step P24, the sign flag F is determined, and if it is negative, -D1 is set to 0.
10 (P25), and if positive, transfer Dl to 010 (P2O).

Next, in step P27, the steering rotation detection means (2)
The detection signal S3. Load S4 (Figure 12) (P
27) Calculate the difference RV (P2O),
Determine the sign of RV (P29.P2O) If L is negative, set the sign flag G to 1 (P31), then perform absolute value conversion (P2O).
32) If it is positive, set the sign flag G to 0 P33
), Table 5 (
If it is zero, the code flag G is set to O (P35), and the data DN is set to 0 (P2O), followed by a step P37.

In step P37, the code flag G is determined, and G=
If it is 1, it is negative, so it is transferred to DNO as -ON (P
2O) If L, G=O, it is positive, so turn ON into DNO
The encoded auxiliary torque data D10 of the electric motor (3) and the induced electromotive voltage data oNO, which are transferred to (P2O), are added and transferred to DO (P2O), and the sign thereof is determined (Pd2. P42), if negative, transfer O to R and 1 to L, which are the data of the motor rotation direction control signal 〒3, in order to rotate the motor (3) to the left (P2O)
L, Determine whether the sign 7 lag F of the steering torque is negative (P44). If it is negative, determine the sign flags F and G of the steering torque and steering rotation (P45) L, the sign flag is one If not, the steering system determines that it is in the return operation state, calculates 1-DH and transfers it to T5 (
P4El) L, transfer data D1 to 〒4 (P47)
Jump to LP80. In step P45, if the sign flags F and G match, it is determined that the steering system is in the forward operation state, and 1 is transferred to T5 (P2O) I.
Add data O1 and data [1N to T4 and transfer (P2
O) and jump to P60. In step P44,
If the sign flag of the steering torque is positive or zero, the return speed is very fast and the process jumps to step P48. If DO is positive in step P42, electric! ! ! (3) Transfer 1 to H and O to L in order to rotate clockwise (P2O) Determine the sign flag F of L and steering torque (
P51). If positive, it is determined whether the sign flags F and G of the steering torque and steering rotation match (P52);
If they do not match, it is determined that the steering system is in the return operation state, and 1-DN is calculated and transferred to T5 (P53).
Transfer l, , Dl to T4 (P54) and jump to P80. If the sign flags F and G match, it is determined that the steering system is in the forward operation state, and 1 is transferred to T5 (P55). After calculating 01+ON to L and T4, it is transferred (P2O). DO at step P41. -0,
Transfer O to R, O to L (P57), and transfer 0 to T5 (P5
8) Transfer 0 (P2O) to T4 and jump to step P80.

In step P60, a motor rotation direction control signal T3 of data R and L is output, and for example, when R-1 and L-0,
FETs (75) and (77) are enabled to drive, and R
-0, L-1, FET (78), (7B)
Make it ready to drive.

Then, in step p61, the motor control signal T4. Output T5. T4 is R-1, FET (77
), and when R=0 and L-1, the FET (7B
) is output. T5 is R=1. FE when L-0
It is output to T(75), and when R-thickness is 0°L-1, it is output to FET.
(78), and the electric motor (3) is driven.

In step P82, motor control signal T4. The detection signal S5 of the current detection means (58) of the electric motor (3) driven by T5 is read, and it is checked whether this value is less than or equal to a set value. If it is less than or equal to the set value, step P3 is performed.
If it is above, the clutch control signal T
2, the electromagnetic clutch (19) is turned off and all operations are stopped.

Furthermore, in addition to the above-mentioned basic operations, the rotational acceleration detection means (5B) performs the following operations. That is, a voltage proportional to the rotational speed of the electric motor (3) is obtained by the power generation m (17) of the rotational acceleration detection means (5B), but the absolute value of this voltage is differentiated by the differentiation circuit (83),
This results in an acceleration signal A5 proportional to the acceleration of the electric motor (3). This acceleration signal A5 is one input of the differential amplifier circuit (71). The other input of the differential amplifier circuit (71) is
This is a motor control signal (an analog signal having the same content as the motor control signal T5) given via the D/A converter (57). The differential amplifier circuit (c) constantly calculates the deviation ΔCC between these two analog signals A4 and A5, and inputs it as a voltage value to the comparator (73). Comparator (73)
inputs the output signal of the triangular wave generation circuit (72) as the reference voltage V, and outputs the square wave signal D1 with the deviation output ΔCC of the differential amplifier circuit (71) as the slice level. For example, the deviation signal ΔCC is a triangular wave. A low level voltage is output during the period when it is larger than the output, and the triangular wave output is the deviation signal Δ
A high level voltage is output during a period in which the voltage exceeds the level of CC. Here, even though the vehicle speed is low, the electric motor (
3), when a large acceleration occurs, the acceleration signal A5 increases, and the negative input of the differential amplifier circuit (71) increases.

Therefore, the deviation voltage Δ which is the output of the differential amplifier circuit (71)
CC increases and the duty ratio of the output square wave of the comparator (73) decreases. The drive unit (74) is configured to give priority to the signal D1 when the duty ratio of the input signal D1 is lower than the duty ratio of the input signal D2, and in this case, the electric motor (3) Despite this, it is driven at a relatively small duty ratio and does not continue to rotate rapidly. Thereafter, as the acceleration decreases and the acceleration signal A5 decreases, the output duty ratio of the comparator (73) increases, and control is performed according to the duty ratio of the motor control signal D2 based on the calculation of the microcomputer unit (55). return. Therefore, for example, even when the electric motor suddenly starts up due to a sudden change in road load, or when the rotation changes rapidly, changes in the rotation of the electric motor are temporarily suppressed, providing a smooth steering feeling and providing a smooth steering feel. Since an increase in rotational acceleration can be suppressed, hunting associated with steering operation can also be prevented.

(Effects of the Invention) As explained above, according to the present invention, the rotational acceleration of the auxiliary torque generating electric motor that occurs due to a change in load is detected, and the electric motor control signal is corrected and changed based on this detection signal. This makes it possible to temporarily suppress sudden changes in the rotation of the electric motor, resulting in stability and responsiveness, as well as a smoother steering feel.
Hunting in the steering system can be prevented, the steering feeling can be further improved, and marketability can be increased.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of the present invention, Figs. 2 to 13 show an embodiment of the electric power steering device of the present invention, and Fig. 2 shows an electromagnetic booster folded at 90°. A vertical cross-sectional view shown in a curved manner, FIG. 3 is a block configuration diagram of the control device,
FIG. 4 is a flowchart showing an outline of the control process, and FIGS. 5 to 13 are characteristic diagrams of each part of the microcomputer unit that determines the basic operation of the electric power steering device. In the drawings, (1) is a steering torque detection means, (2) is a steering rotation detection means, (3) is an auxiliary torque generation electric motor, (4) is an electric motor control signal generation means, (5A) is an electric motor drive means,
(5B) is rotational acceleration detection means. Patent applicant: Agent for Honda Motor Co., Ltd.
Patent Attorney 2 1) Patent Attorney Kuni Ohashi Otoma Patent Attorney Yuyuki Koyama Patent Attorney No 1)
Shigeru Figure 1 Figure 9 TI'a-5zl

Claims (1)

[Claims] A steering torque detection means for detecting the steering torque of the steering system, a steering rotation detection means for detecting the rotation speed of the steering system, and a control signal for the electric motor is determined based on the detection signals from the steering torque detection means and the steering rotation detection means. The electric motor is equipped with a motor control signal generating means for outputting a signal, and a motor driving means for driving the electric motor based on a control signal from the motor control signal generating means, and the electric motor is configured to act on the power of the electric motor to a steering system to reduce steering torque. The type power steering device includes rotational acceleration detection means for detecting rotational acceleration of the electric motor, and a deviation output between an acceleration signal outputted from the rotational acceleration detection means and a control signal outputted from the electric motor control signal generation means. An electric power steering device, characterized in that the electric motor is driven by the electric motor drive means based on the electric motor driving means.