阅读说明：本技术 电动操纵装置 (Electric operating device ) 是由 皆川正明 高僧美树 于 2019-06-03 设计创作，主要内容包括：提供能够提高电动操纵装置的转向操作感的技术。该技术具备：基本控制量计算部(611),其计算与驾驶者的转向操作相应的基本控制量；摩擦力计算部(612),其通过摩擦力模型来计算与转向角相关值相应的摩擦力,并且计算摩擦起因控制量,其中,所述转向角相关值是与所述操纵装置的转向角相关的值,所述摩擦起因控制量起因于所计算出的摩擦力；以及控制量计算部,其根据所述基本控制量及所述摩擦起因控制量,来计算所述转向控制量。(Provided is a technique capable of improving the steering feeling of an electric steering device. The technique is provided with: a basic control amount calculation unit (611) that calculates a basic control amount corresponding to a steering operation by the driver; a friction force calculation unit (612) that calculates a friction force corresponding to a steering angle-related value that is a value related to the steering angle of the steering device, and calculates a friction-cause control amount that is caused by the calculated friction force, using a friction force model; and a control amount calculation unit that calculates the steering control amount based on the basic control amount and the friction-causing control amount.)

1. An electric power steering control device calculates a steering control amount required for steering a steering device,

the electric power steering control device includes:

a basic control amount calculation unit that calculates a basic control amount according to a steering operation by a driver;

a friction force calculation unit that calculates a friction force corresponding to a steering angle-related value that is a value related to a steering angle of the steering device, and calculates a friction-cause control amount that is caused by the calculated friction force, by using a friction force model; and

and a control amount calculation unit that calculates the steering control amount based on the basic control amount and the friction-causing control amount calculated by the friction force calculation unit.

2. The electric power steering control apparatus according to claim 1,

the friction force model is a model formed by connecting a spring component and a coulomb friction component in series,

the frictional force calculation unit calculates the frictional force by using the model in which the spring component and the coulomb frictional component are connected in series.

3. The electric power steering control apparatus according to claim 2,

the frictional force calculation unit calculates the frictional force using a plurality of models in which the spring component and the coulomb frictional component are connected in series,

a plurality of the models each have a spring constant and a coulomb friction force,

the ratio of the coulomb friction force and the spring constant is different according to each model.

4. The electric power steering control apparatus according to any one of claims 1 to 3,

the steering angle correlation value is calculated from a motor rotation angle signal of an electric motor that applies an assist torque or a drag torque to the steering device based on the steering control amount calculated by the control amount calculation section.

5. The electric power steering control apparatus according to any one of claims 1 to 4,

the control device further includes an existing friction cancellation amount calculation unit that calculates a friction cancellation control amount for canceling friction of the steering device,

the control amount calculation unit calculates the steering control amount based on the basic control amount, the friction-causing control amount, and the friction-canceling control amount.

6. The electric power steering control apparatus according to claim 5,

the control amount calculation unit calculates the steering control amount by subtracting the friction cancellation control amount from the addition result of the basic control amount and the friction-caused control amount.

7. The electric power steering control apparatus according to claim 5,

the control amount calculation unit calculates a correction control amount by subtracting the friction-causing control amount from the friction-cancellation control amount, and calculates the steering control amount by subtracting the correction control amount from the basic control amount.

8. The electric power steering control apparatus according to claim 5,

the existing friction cancellation amount calculation unit calculates the friction cancellation control amount based on a steering operation torque generated when the steering device is steered.

9. An electric steering apparatus including the electric power steering control apparatus according to claim 1 to 8.

Technical Field

The present invention relates to an electric power steering control device that controls steering.

Background

Conventionally, a steering device is known which assists a steering control operation by rotation of an electric motor (for example, patent documents 1 and 2). In these steering devices, an appropriate friction torque is applied to the steering device in accordance with the vehicle speed and the steering angle by controlling the current value of the motor.

(Prior art document)

Patent document 1: japanese laid-open patent publication No. 2009-126244 (published 6.11.2009) "

Patent document 2: WO2011/062145 publication (published in 2011 in 5 months and 26 days)

Disclosure of Invention

(problems to be solved by the invention)

With regard to the electric steering apparatus, it is preferable to try to improve the steering feeling.

The purpose of the present invention is to provide a technique capable of improving the steering feeling by an electric steering device.

(means for solving the problems)

In order to achieve the above object, the present invention provides an electric power steering control device for calculating a steering control amount required for steering a steering device, comprising: a basic control amount calculation unit that calculates a basic control amount according to a steering operation by a driver; a friction force calculation unit that calculates a friction force corresponding to a steering angle-related value that is a value related to a steering angle of the steering device, and calculates a friction-cause control amount that is caused by the calculated friction force, by using a friction force model; and a control amount calculation unit that calculates the steering control amount based on the basic control amount and the friction-cause control amount calculated by the friction force calculation unit.

(Effect of the invention)

According to the present invention, the steering feeling can be improved by the electric steering apparatus.

Drawings

Fig. 1 is a schematic configuration diagram of a vehicle according to embodiment 1 of the present invention.

Fig. 2 is a schematic block diagram of the ECU according to embodiment 1 of the present invention.

Fig. 3 is a block diagram showing an example of the configuration of the steering control unit according to embodiment 1 of the present invention.

Fig. 4 shows a model in which a spring component and a coulomb friction component are connected in series.

Fig. 5 shows a steering control amount obtained from the steering control unit according to embodiment 1 of the present invention.

Fig. 6A shows the steering resistance when the steering control is performed using only the basic control amount.

Fig. 6B shows the steering resistance when the steering control is performed using only the friction-causing control amount.

Fig. 6C shows the steering resistance when the steering control is performed using the steering control amount calculated by the addition unit.

Fig. 7 is a block diagram showing an example of the configuration of the steering control unit according to embodiment 2 of the present invention.

Fig. 8A shows the steering resistance when the steering control is performed using only the basic control amount.

Fig. 8B shows the steering resistance when the steering control is performed using the steering control amount calculated by the calculation unit.

Fig. 9 is a block diagram showing an example of the configuration of the steering control unit according to embodiment 3 of the present invention.

Fig. 10 shows a steering control amount obtained from the steering control unit according to embodiment 3 of the present invention.

Fig. 11 shows a friction part of a machine component according to embodiment 4 of the present invention.

Detailed Description

[ embodiment mode 1 ]

Embodiment 1 of the present invention will be described in detail below.

(Structure of vehicle 900)

Fig. 1 is a schematic configuration diagram of a vehicle 900 according to the present embodiment. As shown in fig. 1, a vehicle 900 includes a suspension device (suspension) 100, a vehicle body 200, wheels 300, tires 310, a steering member 410, a joystick 420, a torque sensor 430, a steering angle sensor 440, a torque applying unit 460, a rack-and-pinion mechanism 470, a rack shaft 480, an engine 500, an ecu (electronic Control unit) 600, a power generation device 700, and a battery 800. Among them, the suspension device 100 and the ECU600 constitute the suspension device of the present embodiment.

The steering member 410, the lever 420, the torque sensor 430, the steering angle sensor 440, the torque applying unit 460, the rack-and-pinion mechanism 470, the rack shaft 480, and the ECU600 constitute the electric steering apparatus according to the present embodiment. ECU600 includes an electric power steering control device, and controls the steering of vehicle 900 by the electric power steering device.

A wheel 300 having a tire 310 mounted thereon is mounted on the vehicle body 200 via the suspension device 100. Since the vehicle 900 is a four-wheeled vehicle, 4 suspension devices 100, wheels 300, and tires 310 are provided.

Here, the tires and wheels of the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel are also referred to as: tire 310A and wheel 300A, tire 310B and wheel 300B, tire 310C and wheel 300C, tire 310D and wheel 300D. Similarly, the following may be expressed by respectively designating "a", "B", "C", and "D" as the components attached to the front left wheel, the front right wheel, the rear left wheel, and the rear right wheel.

The suspension device 100 includes a hydraulic shock absorber, an upper support arm, and a lower support arm. In addition, the hydraulic shock absorber includes, as an example, a solenoid valve, which is a solenoid valve, for adjusting a damping force generated by the hydraulic shock absorber. However, the present embodiment is not limited to this, and a solenoid valve other than the solenoid valve may be used as the solenoid valve for adjusting the damping force in the hydraulic shock absorber. For example, the electromagnetic valve may be an electromagnetic valve using an electromagnetic fluid (magnetic fluid).

The engine 500 is additionally provided with a power generation device 700. The electric power generated by power generation device 700 is stored in battery 800.

The steering member 410 operated by the driver is coupled to one end of the lever 420 so as to transmit torque to the lever 420, and the other end of the lever 420 is coupled to the rack and pinion mechanism 470.

The rack and pinion mechanism 470 is a mechanism that converts the amount of rotation of the lever 420 about the axis of rotation into the amount of displacement of the rack shaft 480 in the axial direction thereof. When the rack shaft 480 is displaced in the axial direction thereof, the wheels 300(300A, 300B) are steered via the links 482(482A, 482B) and the articulated arms 484(484A, 484B).

The torque sensor 430 detects a steering operation torque applied to the joystick 420, in other words, a steering operation torque applied to the steering operation member 410, and provides a torque sensor signal expressing the detection result to the ECU 600. More specifically, the torque sensor 430 detects the torsion of a torsion bar provided in the joystick 420, and outputs the detection result as a torque sensor signal. Here, as the torque sensor 430, a known sensor such as a hall effect IC, an MR element, or a magnetic torque sensor can be used.

The steering angle sensor 440 detects the steering angle of the steering operation member 410, and provides the detection result to the ECU 600.

Torque application unit 460 applies an assist torque or a drag torque to joystick 420 according to the steering control amount provided by ECU 600. The torque application unit 460 includes: an assist motor 620 that generates an assist torque or a drag torque according to a steering control amount (also referred to as a motor control amount), and a torque transmission mechanism that transmits a torque generated by the assist motor 620 to the joystick 420. The torque application unit 460 includes: a motor rotation speed sensor that detects the rotation speed of the assist motor 620, and a resolver 625 that is a motor rotation angle sensor that detects the rotation angle of the assist motor.

Specific examples of the "control amount" in the present specification include a current value, a load ratio, a damping rate, a damping ratio, and the like.

In the above description, the phrase "one member is coupled to be capable of transmitting torque" means that one member is coupled to be rotatable in association with rotation of the other member, and includes at least the following cases: one part and the other part are integrally formed with each other; one component is fixed directly or indirectly relative to the other component; one member and the other member are coupled to each other so as to be interlocked with each other via a coupling member or the like.

In the above example, the steering device in which the steering operation member 410 and the rack shaft 480 are always mechanically coupled to each other has been described, but the present embodiment is not limited to this, and the steering device of the present embodiment may be a steer-by-wire type steering device, for example. The following technical matters described in the present specification can be applied to the steer-by-wire type steering device as well.

Fig. 1 shows a so-called column assist type steering device in which a torque applying portion is provided on a steering lever, but the present embodiment is not limited thereto. A so-called rack assist type steering apparatus in which a torque applying portion is provided on a rack shaft may also be employed.

ECU600 performs overall control of various electronic devices provided in vehicle 900. More specifically, the ECU600 controls the magnitude of the assist torque or the magnitude of the drag torque to be applied to the joystick 420 by adjusting the amount of steering control provided to the torque application part 460.

The ECU600 controls the opening and closing of the solenoid valve included in the hydraulic shock absorber included in the suspension device 100 by providing a suspension control amount to the solenoid valve. In order to enable this control, an electric power line for supplying driving power from ECU600 to the solenoid valve is provided.

Further, the vehicle 900 includes: a wheel speed sensor 320 for detecting a wheel speed of each wheel 300, a lateral acceleration sensor 330 for detecting an acceleration in a lateral direction of the vehicle 900, a longitudinal acceleration sensor 340 for detecting an acceleration in a front-rear direction of the vehicle 900, a yaw rate sensor 350 for detecting a yaw rate of the vehicle 900, an engine torque sensor 510 for detecting a torque generated by the engine 500, an engine revolution sensor 520 for detecting a revolution of the engine 500, and a brake pressure sensor 530 for detecting a pressure applied to brake oil provided in the brake device are provided for each wheel 300. The detection results of these various sensors are supplied to ECU 600.

Further, although not shown, the vehicle 900 further includes a brake device that can be controlled by the following system: ABS (Antilock Brake System), which prevents the wheels from locking up when braking; a TCS (Traction Control System) that suppresses wheel spin during acceleration and the like; and a VSA (Vehicle Stability Assist) as a Vehicle behavior Stability control system having an automatic braking function that contributes to yaw moment control, a brake Assist function, and the like during turning.

Here, the ABS, TCS, and VSA compare the wheel speed according to the estimated vehicle body speed with the wheel speed detected by the wheel speed sensor 320, and determine that the vehicle is in a slip state if the difference between these 2 wheel speed values is a predetermined value or more. By performing such processing, the ABS, the TCS, and the VSA perform braking control and traction control that are most suitable for the traveling state of vehicle 900, thereby stabilizing the operation of vehicle 900.

The detection results of the various sensors described above are supplied to the ECU600 and the control signals are transmitted from the ECU600 to the respective units via a CAN (Controller Area Network) 370.

The signals provided to the ECU600 via the CAN370 include, for example, the following signals (the acquisition source is indicated in parentheses).

Wheel speed of 4 wheels (wheel speed sensors 320A-D)

Yaw rate (yaw rate sensor 350)

Longitudinal acceleration (longitudinal acceleration sensor 340)

Lateral acceleration (lateral acceleration sensor 330)

Brake pressure (brake pressure sensor 530)

Engine torque (Engine torque sensor 510)

Engine revolution (Engine revolution sensor 520)

Steering angle (steering angle sensor 440)

Steering operation torque (torque sensor 430)

Fig. 2 is a schematic configuration diagram of ECU 600.

As shown in fig. 2, ECU600 includes a steering control unit (steering control device) 610.

The steering control unit 610 determines the magnitude of the steering control amount to be supplied to the torque application unit 460, with reference to the detection results of various sensors included in the CAN 370.

In the present specification, "reference to" includes "use" and "take into account" and "depend on" and the like.

The process of "determining the magnitude of the controlled variable" includes setting the magnitude of the controlled variable to zero, that is, not supplying the controlled variable.

(steering control section)

Next, turning control unit 610 will be described in more detail with reference to fig. 3. Fig. 3 is a block diagram showing an example of the configuration of the steering control unit 610.

As shown in fig. 3, the steering control unit 610 includes: a basic control amount calculation unit 611, a frictional force calculation unit 612, and an addition unit 615. In the present embodiment, the basic control amount calculation unit 611, the friction force calculation unit 612, and the addition unit 615 are collectively referred to as a control amount calculation unit that calculates a steering control amount. The control amount calculation unit calculates the steering control amount from the basic control amount calculated by the basic control amount calculation unit 611 and the friction-caused control amount calculated by the friction force calculation unit 612.

The basic control amount calculation unit 611 calculates a basic control amount for controlling the magnitude of the assist torque or the drag torque according to the steering operation of the driver, with reference to the steering operation torque supplied from the torque sensor 430. The basic control amount calculated by the basic control amount calculation unit 611 and the friction-causing control amount calculated by the friction force calculation unit 612 are added, and the result of the addition is supplied to the assist motor 620 of the torque application unit 460 as a steering control amount.

The frictional force calculation section 612 calculates the frictional force with reference to the steering angle correlation value representing the steering angle of the steering device. The steering angle related value includes the following two values that occur via a torsion bar built in the joystick 420: a steering operation member-side steering angle correlation value obtained using the value of the steering operation member 410; the gear-box-side steering angle related value is obtained using a value in the aspect of a gear box having the rack and pinion mechanism 470. The frictional force calculation unit 612 calculates the frictional force using either one of these two values.

Among the steering angle correlation values, friction is often the case of the gear box side steering angle correlation value, and the friction can be calculated more accurately by using the rotation angle of the assist motor 620, which is one of the gear box side steering angle correlation values. The assist motor 620 is an electric motor that gives an assist torque or a drag torque to the steering device based on the steering control amount.

For example, the friction force calculation unit 612 acquires a rotation angle signal indicating a rotation angle of the assist motor 620 from the resolver 625, calculates a rack position with reference to the acquired rotation angle signal, and calculates a friction force corresponding to the calculated rack position by a friction force model.

The resolution performance of the rotation angle signal output from the resolver 625 to indicate the rotation angle of the assist motor 620 is high. Therefore, if the friction force is calculated using the value output from the resolver 625 having high resolution, the friction force calculation unit 612 can calculate the friction force generation control amount due to the friction force in more detail. In addition, in the region where the rack displacement is small, the rack displacement can be estimated with higher accuracy by calculating the rack displacement using the assist motor 620.

In this way, since the rotation angle of the assist motor 620 output from the resolver 625 has affinity for the friction force model, the adoption of the rotation angle of the assist motor 620 and the adoption of the friction force model have a superimposed effect, which can contribute to the friction force calculation unit 612 to more accurately calculate the friction force-causing control amount due to the friction force.

The frictional force calculation unit 612 calculates the frictional force corresponding to the rack position by a frictional force model, that is, a model in which the spring component K and the coulomb frictional component F are connected in series, and calculates the frictional force generation control amount resulting from the calculated frictional force.

Fig. 4 shows an example of a model in which a spring component K and a coulomb friction component F are connected in series, and the frictional force calculation unit 612 calculates the frictional force corresponding to the rack position. As shown in fig. 4, the frictional force calculation unit 612 calculates the frictional force using a plurality of models in which the spring component K and the coulomb frictional component F are connected in series. The frictional force calculation unit 612 can calculate the frictional force using, for example, a so-called marcine Model (masking Model) in which a plurality of models in which a spring component K and a coulomb frictional component F are connected in series are connected in parallel to each other to form a marcine Model.

The frictional force calculation unit 612 calculates a frictional force corresponding to the rack position by creating an ideal frictional force waveform corresponding to the rack displacement using a plurality of models in which the spring component K and the coulomb frictional component F are connected in series, and calculates a frictional force generation control amount resulting from the calculated frictional force.

The marcine model shown in fig. 4 is formed by combining the following 3 models in parallel: by a spring component K₁Component F of friction with coulomb₁Models connected in series and composed of spring component K₂Component F of friction with coulomb₂Models connected in series and spring component K₂Component F of friction with coulomb₃A mold formed by connecting in series. The frictional force calculation unit 612 is not limited to this, and may calculate the frictional force using a plurality of, for example, 10 or more of the above models.

Among the plurality of models, a spring component K₁，K₂，K₃Each having a spring constant and a Coulomb friction component F₁，F₂，F₃The ratio between the respective coulomb frictional forces differs according to each model. The ratio F of the spring constant to the Coulomb friction force possessed by each model₁/K₁、F₂/K₂、F₃/K₃For example, it can be set to F₁/K₁＜F₂/K₂＜F₃/K₃The relationship (2) of (c). Each model has a ratio F of spring coefficient to Coulomb friction₁/K₁、F₂/K₂、F₃/K₃The ideal frictional force waveform output by driving these models can be arbitrarily set in consideration. The frictional force calculation unit 612 outputs a friction-causing control amount, which is the amount of control for causing friction, to the addition unit 615 based on the rack positionA current proportional to a friction signal, wherein the friction signal is driven by a spring component K₁～₃Component F of friction with coulomb₁～₃The models connected in series are output.

FIG. 5 shows the use of a spring composition K₁～₃Component F of friction with coulomb₁～₃A frictional force waveform produced by serially connecting the models. As shown in fig. 5, in the frictional force calculation portion 612, the rack position a immediately after the steering operation member 410 is reversed₀And rack position A₁All models of coulomb friction components are fixed. Thereby, the friction force is realized from C₀Is raised to C₁The friction force waveform of (a). And slave C described later₁To C₂Rising of, from C₂To C₃Friction force from C₀To C₁Is steeper.

Next, in the frictional force calculation section 612, at the slave rack position a₁To rack position A₂In the interval of (1), the spring component K₁Component F of friction with coulomb₁A model slip formed by connecting in series, wherein a spring component K₁And a Coulomb friction component F₁The ratio of (c) is the smallest among the above-mentioned 3 ratios. Thereby, the friction force is realized from C₁Is raised to C₂The friction force waveform of (2), this ratio is from C₀To C₁The rise in (c) is more gradual.

Next, in the frictional force calculation section 612, at the slave rack position a₂To rack position A₃In the interval of (1), the spring component K₁And a Coulomb friction component F₁Models connected in series and spring component K₂Component F of friction with coulomb₂A model slip formed by connecting in series, wherein a spring component K₁And a Coulomb friction component F₁Is the smallest among the above-mentioned 3 ratios, and the spring component K₂And a Coulomb friction component F₂Is centered among the 3 ratios mentioned above. Thereby, the friction force is realized from C₂Is raised to C₃The friction force waveform of (2), this ratio is from C₁To C₂The rise in (c) is more gradual.

Finally, in the frictional force calculation section 612, a plurality of spring components K are formed₁～₃Component F of friction with coulomb₁～₃The models connected in series are all slippery. Thereby, the frictional force is maintained at a fixed value C₃。

In this way, the friction force calculation unit 612 sequentially slides a plurality of models in which the spring component K and the coulomb friction component F are connected in series from a model in which the spring coefficient and the coulomb friction force are relatively small, thereby realizing a friction force waveform in which the friction force gradually increases. Further, by increasing the number of models in which the spring component K and the coulomb friction component F are connected in series, which are used by the friction force calculation unit 612, it is possible to create a friction force waveform in which the friction force rises more gradually.

In this way, when the frictional force is calculated using a plurality of models in which the spring component K and the coulomb friction component F are connected in series, the frictional force waveform spreads toward the reversal point of the previous operation as a point-symmetric waveform line in the steering operation and the returning operation of the steering operation member 410. Therefore, the frictional force calculation unit 612 can realize an ideal frictional force waveform by using a plurality of models in which the spring component K and the coulomb frictional component F are connected in series without detecting whether the steering operation member 410 is the steering operation or the return operation.

The value calculated by the friction force calculation unit 612 using the above model has a hysteresis relationship between the steering angle-related value and the friction-related control amount. The friction force calculation unit 612 may have a hysteresis map in advance, in which a relationship between the steering angle related value and the friction-causing control amount calculated in advance using the model is stored. The friction force calculation unit 612 may calculate the friction-causing control amount using the acquired steering angle-related value and the hysteresis map.

The frictional force calculation unit 612 may calculate the frictional force using a frictional force Model other than the maring Model (masking Model). Examples of the friction force Model other than the Masing Model include Maxwell (Maxwell) Model, Dahl (Dahl) Model, and lugle (Lugre) Model, and a Model obtained by combining various friction force models may be used. In the Maxwell model, the frictional force can be calculated by the series connection of the rigid component and the damping component. The designer can freely make the waveform desired by the designer using these frictional force models.

The adder 615 adds the friction-causing control amount calculated by the friction force calculator 612 to the basic control amount calculated by the basic control amount calculator 611, thereby calculating the steering control amount. The steering control amount calculated by the addition unit 615 is supplied to the assist motor 620 of the torque application unit 460.

Fig. 6A shows the steering resistance when steering control is performed using only the basic control amount calculated by the basic control amount calculation unit 611.

Fig. 6B shows the steering resistance when steering control is performed using only the friction-cause control amount calculated by the friction-force calculation unit 612.

Fig. 6C shows the steering resistance when the steering control is performed using the steering control amount calculated by the addition unit 615.

In this way, the steering control unit 610 obtains a steering control amount by adding the basic control amount calculated by the basic control amount calculation unit 611 to the friction-caused control amount due to the friction calculated by the friction calculation unit 612 using a plurality of models in which the spring component K and the coulomb friction component F are connected in series, and controls the steering device by the steering control amount. Therefore, at the initial stage of the steering operation, the frictional force can be gently increased, so that a minute steering operation is easily performed. Further, since there is a clear change in the steering force even with a slight change in the steering angle, the steering feeling can be improved by making the slight change in the steering angle felt by the hand touch.

[ embodiment 2 ]

In the embodiment 1, the steering control unit 610 calculates the steering control amount based on the basic control amount corresponding to the steering operation amount and the friction-causing control amount calculated by the friction force calculation unit 612, but the invention described in the present specification is not limited to this. The steering control unit 610a according to embodiment 2 further includes an existing friction cancellation amount calculation unit 613 in addition to embodiment 1, and the existing friction cancellation amount calculation unit 613 calculates a friction cancellation control amount for canceling a frictional force of the electric steering device. The steering control unit 610a calculates a steering control amount from the basic control amount, the friction-causing control amount, and the friction-canceling control amount calculated by the existing friction-canceling amount calculating unit 613. For convenience of explanation, members having the same functions as those described in the above embodiments are given the same reference numerals, and are not described again.

Fig. 7 is a block diagram showing an example of the configuration of the steering control unit 610a according to the present embodiment.

As shown in fig. 9, steering control unit 610a differs from steering control unit 610 described in embodiment 1 in the following points.

That is, the steering control unit 610a includes the existing friction cancellation amount calculation unit 613. In the present embodiment, the basic control amount calculation unit 611, the frictional force calculation unit 612, the existing friction cancellation amount calculation unit 613, and the calculation unit 615a are collectively referred to as a control amount calculation unit.

The existing friction cancellation amount calculation unit 613 calculates the amount of friction of the steering device, that is, calculates the amount of friction according to the existing friction characteristics of the mechanical components such as the steering operation member 410, the steering lever 420, the torque application unit 460, the rack-and-pinion mechanism 470, and the rack shaft 480.

The existing friction cancellation amount calculation part 613 calculates the existing friction amount from at least one of the following (1) and (2): (1) a steering angle of the steering member 410 detected by the steering angle sensor 440; and (2) a steering operation torque detected by the torque sensor 430, which is generated in the steering operation member 410 when the steering operation is performed on the steering device.

Note that, if the steering angle is used for calculating the existing friction amount, the steering angle may be calculated using the motor rotation angle calculated by the resolver 625 and the steering torque detected by the torque sensor 430. Specifically, the motor rotation angle may be added to a correction angle calculated based on the steering torque, and the addition result may be regarded as the steering angle. In this case, the correction angle based on the steering operation torque can be calculated by multiplying the detected steering operation torque by a predetermined coefficient (for example, the inverse of the spring rate of the torsion bar). Thus, even if the steering angle sensor 440 is not provided, the steering angle can be accurately determined, and the existing friction amount can be calculated.

The existing friction cancellation amount calculation part 613 calculates a friction cancellation control amount for subtracting (canceling) the existing friction amount from the final steering control amount, based on the calculated existing friction amount.

The calculation unit 615a calculates the steering control amount by subtracting the friction cancellation control amount calculated by the existing friction cancellation amount calculation unit 613 from the addition result of the basic control amount and the friction-caused control amount. The steering control amount calculated by the calculation unit 615a is supplied to the assist motor 620 of the torque application unit 460.

Fig. 8A shows the steering resistance when steering control is performed using only the basic control amount calculated by the basic control amount calculation unit 611.

Fig. 8B shows the steering resistance when steering control is performed using the steering control amount calculated by the calculation unit 615 a.

According to the above configuration, steering control unit 610a calculates the steering control amount by subtracting the friction cancellation control amount from the addition result of the basic control amount and the friction-causing control amount. Therefore, the steering control unit 610a can calculate an ideal steering control amount according to the friction characteristics of the mechanical components of the electric manipulator.

[ embodiment 3 ]

In the embodiment 2, the steering control unit 610a calculates the steering control amount by subtracting the friction cancellation control amount from the addition result of the basic control amount and the friction-related control amount, but the invention described in the present specification is not limited to this. The steering control unit 610b according to embodiment 3 includes a calculation unit (correction control amount calculation unit) 616 in addition to the calculation unit 615a in embodiment 2. The steering control unit 610b outputs the basic control amount calculated by the basic control amount calculation unit 611 and a correction control amount obtained by subtracting the friction-caused control amount from the friction-cancellation control amount. For convenience of explanation, members having the same functions as those described in embodiments 1 and 2 are given the same reference numerals, and are not described again.

Fig. 9 is a block diagram showing an example of the configuration of the steering control unit 610b according to the present embodiment.

As shown in fig. 9, steering control unit 610b differs from steering control unit 610a described in embodiment 2 in the following points.

That is, the steering control unit 610b includes the calculation unit 616, but does not include the calculation unit 615 a.

The calculation unit 616 subtracts the friction-causing control amount calculated by the friction force calculation unit 612 from the friction-offset control amount calculated by the existing friction-offset calculation unit 613, thereby calculating a correction control amount.

The subtraction unit 617 subtracts the correction control amount calculated by the calculation unit 616 from the basic control amount calculated by the basic control amount calculation unit 611.

In the present embodiment, the basic control amount calculation unit 611, the friction force calculation unit 612, the existing friction cancellation amount calculation unit 613, the calculation unit 616, and the subtraction unit 617 are collectively referred to as a control amount calculation unit. The control amount calculation unit calculates a steering control amount by subtracting the correction control amount from the basic control amount.

Fig. 10 shows a waveform of the steering control amount calculated by the control amount calculation section. In fig. 10, Fr _ curve1 is a waveform of the steering resistance when steering control is performed using the basic control amount calculated by the basic control amount calculation unit 611, and Fr _ curve2 is a waveform of the steering resistance when steering control is performed using the ideal steering control amount. Fr _ diff is the difference between the ideal steer resistance and the steer resistance when the basic control is used.

The calculation unit 616 subtracts the friction-causing control amount from the friction-canceling control amount to calculate a correction control amount corresponding to Fr _ diff. As shown in fig. 10, the control amount calculation unit subtracts the correction control amount (corresponding to Fr _ diff) calculated by the calculation unit 616 from the basic control amount (corresponding to Fr _ current 1) calculated by the basic control amount calculation unit 611, thereby calculating an ideal steering control amount (corresponding to Fr _ current 2).

The control amount calculation section provides the calculated steering control amount to the assist motor 620 of the torque application section 460.

According to these aspects, the control amount calculation unit calculates the correction control amount by subtracting the friction-causing control amount from the friction-canceling control amount, and calculates the steering control amount by subtracting the calculated correction control amount from the basic control amount based on the basic control amount. Thereby, the frictional force can be gently increased, and the influence of the disturbance of the external vibration on the calculation of the steering control amount can be suppressed. Therefore, even if the minute steering plus and minute return are repeated during the steering operation, the minute steering angle change can be sensed by the tactile sensation of the hand, and the steering operation feeling can be improved.

[ embodiment 4 ]

Embodiment 4 describes an arrangement in which the electric steering apparatus described in embodiments 1, 2, and 3 further increases the flexibility of the friction portion of the mechanical member, thereby improving the steering feeling. The scheme of embodiment 4 can be applied to each of embodiments 1, 2, and 3 described above.

Fig. 11 shows an example of a frictional portion of a mechanical component in the electric manipulator, that is, a rack shaft 480 and a rack guide 495. As shown in fig. 11, a resin bearing 496 is provided between the rack shaft 480 and the rack guide 495. A recess 495a along the rack shaft extending direction is formed in the rack guide 495, and a resin bearing 496 is fitted into the recess.

In fig. 11, the y-axis direction shows the direction in which the rack shaft 480 extends, the z-axis direction shows the vertical direction perpendicular to the y-axis, and the x-axis direction shows the directions perpendicular to both the y-axis and the z-axis.

As shown in fig. 11, by increasing the thickness (thickness in the z-axis direction) of the resin bearing 496, the flexibility of the resin bearing 496 is increased, and thereby the frictional force at the time when the rack shaft 480 starts to slip against the reaction torque can be gently increased by the deformation of the resin bearing 496.

As shown in fig. 11, the thickness of the resin bearing 496 (the thickness in the z-axis direction) is preferably changed in the x-axis direction. Thus, the amount of deformation of the resin bearing before the rack shaft starts slipping against the reaction torque may be different for each position on the resin bearing 496, and the increase in the frictional force may be gently curved instead of stepped.

The friction portion between the rack shaft 480 and the rack guide 495 is not limited, and the friction portion of various mechanical parts in the electric steering apparatus may be increased in thickness by a resin bearing and may be made uneven, so that the frictional force caused by the steering operation in the electric steering apparatus may be gently increased, and the steering feeling may be improved.

[ implementation example based on program software ]

The control block (steering control Unit 610) of the ECU600 may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by program software using a CPU (Central Processing Unit).

When implemented by program software, ECU600 includes: a CPU that executes a program software command for realizing each function, a ROM (Read Only Memory) or a storage device (these are referred to as "storage medium") that stores the program software and various data so that a computer (or CPU) can Read them, a RAM (Random Access Memory) that expands the program software, and the like. Thus, the object of the present invention can be achieved by reading and executing the program software from the storage medium by a computer (or CPU). As the storage medium, a "non-transitory tangible medium" such as a memory tape, a memory disk, a memory card, a semiconductor memory, a programmable logic circuit, or the like can be used. The program software may be supplied to the computer through any transmission medium (a communication network, a broadcast wave, or the like) through which the program software can be transmitted. Here, the present invention can be realized even if the form of the program software is a data signal embodied by electronic transmission and loaded on a carrier wave.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention, and embodiments obtained by appropriately combining the technical means disclosed in the respective embodiments are also included in the technical scope of the present invention.

< description of reference numerals >

410 steering operation member

420 operating rod

430 torque sensor

440 steering angle sensor

460 part for applying torque

600 ECU

610. 610a, 610b steering control section (steering control device)

611 basic control amount calculating unit

612 friction amount calculating part

612 frictional force calculating section

613 existing friction cancellation amount calculating unit

616 calculation unit (correction control quantity calculation unit)

617 subtraction part

620 auxiliary motor

625 resolver

F. F1, F2, F3 Coulomb friction component

K. K1, K2, K3 spring components.

The claims (modification according to treaty clause 19)

1. An electric power steering control device calculates a steering control amount required for steering a steering device,

the electric power steering control device includes:

a basic control amount calculation unit that calculates a basic control amount according to a steering operation by a driver;

a friction force calculation unit that calculates a friction force corresponding to a steering angle related value that is a value related to a steering angle of the steering device, and calculates a friction-causing control amount that is caused by the calculated friction force, by using a friction force model; and

a control amount calculation unit that calculates the steering control amount based on the basic control amount and the friction-cause control amount calculated by the friction force calculation unit,

wherein the content of the first and second substances,

the friction force model is a model formed by connecting a spring component and a coulomb friction component in series,

the frictional force calculation unit calculates the frictional force using a plurality of models in which the spring component and the coulomb frictional component are connected in series,

a plurality of the models each have a spring constant and a coulomb friction force,

the ratio of the coulomb friction force and the spring constant is different according to each model,

the frictional force calculation unit drives the plurality of models to output frictional force so that the models are sequentially slid from the relatively small model based on the steering angle correlation value.

2. The electric power steering control apparatus according to claim 1,

the steering angle correlation value is calculated from a motor rotation angle signal of an electric motor that applies an assist torque or a drag torque to the steering device based on the steering control amount calculated by the control amount calculation section.

3. The electric power steering control apparatus according to claim 1 or 2,

the control device further includes an existing friction cancellation amount calculation unit that calculates a friction cancellation control amount for canceling friction of the steering device,

the control amount calculation unit calculates the steering control amount based on the basic control amount, the friction-causing control amount, and the friction-canceling control amount.

4. The electric power steering control apparatus according to claim 3,

the control amount calculation unit calculates the steering control amount by subtracting the friction cancellation control amount from the addition result of the basic control amount and the friction-caused control amount.

5. The electric power steering control apparatus according to claim 3,

the control amount calculation unit calculates a correction control amount by subtracting the friction-causing control amount from the friction-cancellation control amount, and calculates the steering control amount by subtracting the correction control amount from the basic control amount.

6. The electric power steering control apparatus according to claim 3,

the existing friction cancellation amount calculation unit calculates the friction cancellation control amount based on a steering operation torque generated when the steering device is steered.

7. An electric steering apparatus including the electric power steering control apparatus according to claim 1 to 6.