JP4390176B2 - Steering device with redundant system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steering system having a redundant system, and in particular, doubles an electronic drive control system for operating a motor, and further doubles a signal line and a power line to increase system tolerance against failure of the system and a harness (line). The present invention relates to a steering apparatus such as an electric power steering apparatus that is improved in system reliability.
[0002]
[Prior art]
Examples of the steering device include an electric power steering device and a steer-by-wire system. An electric power steering device as an example of a steering device is a support device that assists a steering force by interlocking a motor when a driver operates a steering wheel (steering handle) while driving an automobile. The electric power steering device uses a steering torque signal from a steering torque detector that detects a steering torque generated in a steering shaft by a driver's steering operation, and a vehicle speed signal from a vehicle speed detector that detects a vehicle speed, and Based on the control operation of a control device (ECU (Electric Control Unit): electronic control unit), a driving motor that outputs an auxiliary steering force is driven and controlled to reduce the driver's manual steering force. The ECU is driven by power supplied from a battery installed in front of the vehicle. In the control operation by the motor, a target current value of a motor current to be supplied to the motor is set based on the steering torque signal and the vehicle speed signal, and a signal (target current signal) related to the target current value and the motor that actually flows to the motor are set. The difference from the motor current signal fed back from the motor current detection unit for detecting the current is obtained, and proportional / integral compensation processing (PI control) is performed on the deviation signal to generate a signal for controlling the drive of the motor. Yes.
[0003]
The assist motor driven by the ECU transmits the rotation output to a gear box including a rack and pinion mechanism connected to the steering shaft via a power transmission mechanism (reduction gear). This assists the driver's steering force operating the steering wheel.
[0004]
As described above, the electric power steering apparatus includes a sensor system such as a steering torque detector, an ECU including a CPU and a drive circuit system, a battery that drives the ECU, and a current supply system that supplies motor current from the ECU to the support motor. An electronic drive control system is provided, and each of these connections is made by a single harness.
[0005]
[Problems to be solved by the invention]
In a conventional electric power steering apparatus, an electronic drive control system for driving a motor provided in an ECU and a portion related thereto is a precision electronic device, and is therefore installed in a vehicle interior that is a good environment. For example, it may be installed near the passenger seat. For this reason, the transmission path from ECU to a battery, a motor, etc. becomes long. Moreover, in this transmission line, it connects with the harness which bundled the several signal line and power line so that electric noises, such as electromagnetic waves and static electricity, may not mix.
[0006]
The harness has one harness connecting the battery and the ECU, one harness connecting the motor and the ECU, and one harness connecting the torque detection unit and the ECU (for example, a feature that is not known in the prior application). (See FIG. 1 of Japanese Patent Application No. 2002-239627 (August 20, 2002)). For this reason, when the harness is affected by a stepping stone or the like, the devices connected by the harness are in a failure state.
[0007]
In view of the above problems, an object of the present invention is to provide a steering apparatus having a redundant system that allows the apparatus to continue to be driven even if the harness is broken due to a stepping stone or the like.
[0008]
[Means and Actions for Solving the Problems]
In order to achieve the above object, a steering system having a redundant system according to the present invention is configured as follows.
[0009]
The first steering device (corresponding to claim 1) includes torque detection means for detecting a steering torque, target current determination means for determining a motor current in accordance with the steering torque output from the torque detection means, and the target The steering device includes a drive circuit unit that supplies current to the motor according to the motor current determined by the current determination unit, the drive circuit unit having the same drive circuit of two paths, and at least two motor harnesses , each of the two torque sensor harness with wiring through different locations of the vehicle even without low, the one of the at least two power harness left side portion of the vehicle, along the right side surface of the other one It is characterized by wiring each .
The second steering device (corresponding to claim 2) has one torque detection means in the above configuration, and one torque sensor of at least two torque sensor harnesses connected to the torque detection means. The harness is detoured from the rack shaft to the front of the vehicle and wired to the torque detection means.
[0010]
In the above steering apparatus, a drive circuit for supplying a motor current to the motor is provided in two paths, and further, electric power is supplied to at least two motor harnesses that connect the drive circuit unit and the motor, and the drive circuit unit and the drive circuit unit. Since at least two power harnesses for connecting the power supply and at least two torque sensor harnesses for connecting the torque detection unit and the target current determination unit are provided through different locations of the vehicle, either one of the driving Even if a failure occurs in the circuit, the motor current can be supplied by the remaining drive circuit, and even if one of the two harnesses is affected by a stepping stone, etc., the other harness can keep the system down. It is possible to prevent, maintain the system and maintain high system reliability.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
[0012]
The configurations, shapes, sizes, and arrangement relationships described in the embodiments are merely schematically shown to the extent that the present invention can be understood and implemented. Therefore, the present invention is not limited to the embodiments described below, and can be modified in various forms without departing from the scope of the technical idea shown in the claims.
[0013]
In this embodiment, an example of an electric power steering device will be described as an example of a steering device.
[0014]
FIG. 1 is a perspective view showing a wiring state inside a vehicle front end provided with a steering apparatus having a redundant system according to the present invention. FIG. 2 is a plan view showing a wiring state inside a vehicle provided with a steering device having a redundant system according to the present invention. Hereinafter, a steering apparatus having a redundant system according to the present invention will be described with reference to FIGS. An electric power steering device 10 is provided at the front of the vehicle 1. The electric power steering device 10 is configured to give auxiliary steering torque to the steering shaft 12 and the like connected to the steering wheel 11. The steering shaft 12 is connected at its upper end to the steering wheel 11, changes the direction of the rotational force via a joint 13 on the way, and transmits the rotational force to the lower end. A rack and pinion mechanism 15 is formed at the lower end of the steering shaft 12 by a pinion gear and a rack shaft 14 attached to the lower end. Tie rods 16 are provided at both ends of the rack shaft 14, and front wheels 17 are attached to the outer ends of the tie rods 16.
[0015]
For example, a motor 19 with a brush or a brushless motor is provided to the rack shaft 14 via a power transmission mechanism (reduction gear). The motor 19 outputs a rotational force (torque) that assists the steering torque, and applies this rotational force to the rack shaft 14 via the power transmission mechanism. A steering torque detector 20 is provided on the steering shaft 12. The steering torque detector 20 detects the steering torque applied to the steering shaft 12 when, for example, the steering torque generated by the driver operating the steering wheel 11 is applied to the steering shaft 12.
[0016]
Reference numeral 22 denotes a control device (ECU) composed of a computer (microcomputer or the like). The control device 22 takes in the steering torque signal T output from the steering torque detector 20 and the vehicle speed signal V output from the vehicle speed detector (not shown), and based on the information on the steering torque and the information on the vehicle speed. A drive control signal for controlling the rotation operation of the motor 19 is output.
[0017]
When the driver operates the steering wheel 11 to steer in the traveling direction during the traveling operation of the automobile, the rotational force based on the steering torque applied to the steering shaft 12 is applied to the rack shaft 14 via the rack and pinion mechanism 15. It is converted into a linear motion in the axial direction, and further, the traveling direction of the front wheel 17 is changed through the tie rod 16. At this time, at the same time, the steering torque detector 20 attached to the steering shaft 12 detects the steering torque corresponding to the steering by the driver at the steering wheel 11 and converts it into an electrical steering torque signal T. A steering torque signal T is output to the control device 22. The control device 22 generates a motor current for driving the motor 19 based on the steering torque signal T and the vehicle speed signal V. The motor 19 driven by this motor current causes auxiliary steering torque to act on the rack shaft 14 via a power transmission mechanism. By driving the motor 19 as described above, the steering force applied by the driver to the steering wheel 11 is reduced.
[0018]
In the above configuration, two motor harnesses 19 </ b> R and 19 </ b> L connecting the control device 22 and the motor 19 are provided through different places of the vehicle 1. The motor harness 19R and the motor harness 19L are connected to the motor 19 through different places from the control device 22 installed under the passenger seat 26L.
[0019]
Two power harnesses 25 </ b> R and 25 </ b> L connecting the control device 22 and the battery 25 are provided so as to pass through different locations along the left and right side portions of the vehicle 1. In the figure, the power harness 25R is connected to the battery 25 along the right side surface of the vehicle 1 from the control device 22 installed under the passenger seat 26L, under the driver seat 26R. The power harness 25L is connected from the control device 22 along the left side surface of the vehicle 1 to the battery 25 through the front portion of the vehicle 1.
[0020]
Two torque sensor harnesses 20 </ b> R and 20 </ b> L that connect the control device 22 and the steering torque detection unit 20 are provided through different locations of the vehicle 1. The torque sensor harness 20R is connected to the steering torque detector 20 at the shortest possible distance, while the torque sensor harness 20L is detoured along the left side surface of the vehicle 1 and connected to the steering torque detector 20.
[0021]
Each of the harnesses 19R, 19L, 25R, 25L, 20R, and 20L is provided in a portion that is not easily affected by a stepping stone or the like, and is disposed so as to pass through different locations of the vehicle 1. Thereby, even if one harness is affected by a stepping stone or the like and is disconnected, the operating state can be continuously maintained by the other harness.
[0022]
The control device 22 includes a target current determination unit 31 and a control unit 32 as shown in FIG. The target current determination unit 31 determines a target auxiliary torque mainly based on the steering torque signal T, and a signal (target current signal) IT related to a target current value required for supplying the target auxiliary torque from the motor 19. Is output.
[0023]
The general configuration of the control unit 32 will be outlined. The control unit 32 includes a deviation calculation unit, a motor control unit, a motor drive unit, and a current value detection unit as functional elements or electrical circuit elements realized in software. The motor control unit includes a deviation current control unit and a PWM signal generation unit. The deviation current control unit generates and outputs a drive current signal for controlling the motor current based on the current signal given from the deviation calculation unit. The PWM signal generation unit generates a PWM (pulse width modulation) signal for PWM driving the motor 19 based on the drive current signal given from the deviation current control unit. The motor drive unit includes a gate drive circuit unit and a motor drive (drive) circuit (H-type bridge circuit formed by four FETs). The gate drive circuit unit switches the motor drive circuit based on the drive control signal (PWM signal). As described above, the control device 22 performs PWM control on the motor current supplied from the in-vehicle battery (DC power supply) 25 to the motor 19 based on the steering torque detected by the steering torque detection unit 20 by the motor drive circuit. Controls the output power (auxiliary steering torque).
[0024]
Next, a specific configuration of the control unit (ECU) 22 shown in FIG. 3 will be described with reference to FIG. 4 according to the first embodiment of the present invention.
[0025]
The detection signal output terminal of the steering torque detector 20 has both side terminals 20a and 20b and a center terminal 20c. Two each of the terminals 20a, 20b and the center terminal 20c are provided. Between the both-side terminals 20a and 20b, the center terminal 20c, and the control device 22 of the steering torque detection unit 20, two paths of electrical connection units 41a and 41b are provided. The electrical connection portions 41a and 41b are portions including the torque sensor harnesses 20R and 20L and a coil connection portion. On the input side of the control device 22, torque signal input portions 42a and 42b are provided corresponding to the electrical connection portions 41a and 41b. The electrical connection portions 41a and 41b pass through different places of the vehicle 1 like the torque sensor harnesses 20R and 20L described above.
[0026]
Inside the control device 22, three CPUs (1-3) 43a, 43b, 43c are provided. Each of the two torque signal input units 42a and 42b has three output terminals, and the corresponding output terminal between the two torque signal input units 42a and 42b outputs the same signal (SG11, SG12, SG13). To do. The same signal is input to each of the three CPUs (1-3) 43a to 43c from the two torque signal input units 42a and 42b via two paths. The three CPUs (1-3) 43a-43c are connected in two in an arbitrary combination, and each of the three CPUs (1-3) 43a-43c is configured to be able to make a majority decision. Therefore, for example, when a failure occurs in the electrical connection portions 41a and 41b from the steering torque detection unit 20 (electrical interruption by a stepping stone of the torque sensor harnesses 20R and 20L, etc.), a determination on the failure is made by a majority decision method. Is configured to do. The above-described various functional elements are realized in software by the CPUs (1-3) 43a-43c. Preferably, two target current determination units 31 are formed, and each of the steering torque signals from the two paths is input to the two target current determination units, and each target current determination unit determines a target current. ing.
[0027]
Two motor drive (drive) circuits (1, 2) 44a, 44b, two booster circuits (1, 2) 45a, 45b, two F / S relays (1, 1, 2) 46a, 46b and two power relays (1, 2) 47a, 47b are provided. These two elements have the same configuration and action. The motor drive circuit (1) 44a corresponds to the CPU (1) 43a and a prohibition circuit (1) 48a is connected between them, and the motor drive circuit (2) 44b corresponds to the CPU (3) 43c. The prohibition circuit (3) 48b is connected between the two. As a result, with respect to the drive control of the motor 19, the first motor drive circuit unit (first path) is controlled by the CPU (1) 43a, the prohibition circuit (1) 48a, and the motor drive circuit (1) 44a in the control device 22. The second motor drive circuit unit (second path) is formed by the CPU (3) 43c, the prohibition circuit (3) 48b, and the motor drive circuit (2) 44b.
[0028]
The signal output from the CPU (2) 43b is applied to the prohibition circuit (2) 48c, and the output signal of the prohibition circuit (2) 48c is applied to the prohibition circuit (1) 48a. A signal output from the CPU (1) 43a is given to the prohibition circuit (1) 48a.
[0029]
The motor (M) 19 is a motor with a brush. In the motor 19, two pairs (49a, 49b) of a pair of brushes are provided. The motor current I _M1 output from the motor drive circuit (1) 44a of the first motor drive circuit section (first path) is supplied to the motor 19 through the brush 49a. The motor current I _M2 output from the motor drive circuit (2) 44b of the second motor drive circuit section (second path) is supplied to the motor 19 through the brush 49b. Therefore, in accordance with the first and second motor driving circuits, the brushed motor 19 is also provided with two brush pairs. Two motor harnesses 19 </ b> R and 19 </ b> L that supply the motor currents I _M1 and I _M2 are provided through different locations of the vehicle 1.
[0030]
The battery 25 supplies power to the control device 22. A power supply path from the battery 25 is formed by two power harnesses 25R and 25L. The power harness 25R passes from the control device 22 installed under the passenger seat 26L, passes under the driver seat 26R, and is connected to the battery 25 along the right side surface of the vehicle 1. The power harness 25L is connected to the control device 22 from the control device 22. Along the left side of the vehicle 1, it passes through the front of the vehicle 1 and is connected to the battery 25. In the power harness 25R, the first energization path is directly connected as the second energization path via the power relay (1) 47a and the booster circuit (1) 45a, and the third energization path is the power relay ( 1) Electric power is supplied to the motor drive circuit (1) 44a via 47a. Similarly, in the power harness 25L, the first energization path is directly connected to the second energization path via the power relay (2) 47b and the booster circuit (2) 45b, and the third energization path is defined as the third energization path. Electric power is supplied to the motor drive circuit (2) 44b via the power relay (2) 47b.
[0031]
The motor current I _M1 output from the motor drive (1) circuit 44a is detected by the current sensor 52a and fed back to each of the CPUs 43a to 43c. The motor current I _M2 output from the motor drive circuit (2) 44b is detected by the current sensor 52b and fed back to each of the CPUs 43a to 43c.
[0032]
In the configuration of the control device 22 according to the first embodiment, an electric connection portion (torque sensor harnesses 20R, 20L) from the steering torque detection unit 20 to the control device 22 and a motor drive circuit unit including motor drive circuits 44a, 44b. The power supply path (power harnesses 25R, 25L) from the battery 25 to the motor drive circuits 44a, 44b and the current supply path (motor harnesses 19R, 19L) to the brush pair (49a, 49b) of the motor 19 are connected in parallel. Since there are two paths (double) based on the various connection relations, and each harness passes through different places of the vehicle 1, even if a failure occurs in any place, the electric power steering device is used in the remaining paths. It can be operated and the system of the electric power steering device is prevented from being down by providing a redundant system. It can be.
[0033]
The motor drive circuits 44a and 44b of two paths provided in parallel connection relation are controlled to drive one of the motor drive circuits 44a and 44b, and the other motor drive circuit is operated when a failure occurs. Further, the motor drive circuits 44a and 44b of the two paths are operated simultaneously to perform motor drive control in both, and when a failure occurs in one harness or circuit, the motor drive control is performed in the remaining motor drive circuit. You can also. The prohibition circuits 48a, 48b, and 48c described above are means for selecting a circuit system used for motor drive control within the control device 22.
[0034]
In the above-described embodiment, the system configuration of the electric power steering apparatus is provided with redundancy by a double configuration. However, the present invention is not limited to this, and it is needless to say that the configuration can be triple or more.
[0035]
Next, a specific configuration of the control device 22 according to the second embodiment of the present invention will be described with reference to FIG. In FIG. 5, elements that are substantially the same as those described in FIG. 4 are given the same reference numerals, and descriptions thereof are omitted. A characteristic configuration according to the second embodiment is that two motors are provided. There are motor drive circuits 44a and 44b for the motors 19a and 19b, respectively. The motors 19a and 19b are brushed motors. Each of the motors 19a and 19b is provided with a pair of brushes (49a and 49b). The motor current I _M1 output from the motor drive circuit (1) 44a of the first motor drive circuit section (first path) is supplied to the motor 19a through the brush 49a. The motor current I _M2 output from the motor drive circuit (2) 44b of the second motor drive circuit section (second path) is supplied to the motor 19b through the brush 49b. Two motor harnesses 19 </ b> R and 19 </ b> L that are current supply paths for supplying the motor currents I _M1 and I _M2 to the motors 19 a and 19 b are provided through different locations of the vehicle 1. As a result, even if a failure occurs in any part of the motor harness 19R, 19L, the electric power steering device can be operated in the remaining path, and the system failure of the electric power steering device is prevented by providing a redundant system. be able to.
[0036]
Next, a specific configuration of the control device 22 according to the third embodiment of the present invention will be described with reference to FIG. In FIG. 6, elements that are substantially the same as those described in FIG. 4 or 5 are given the same reference numerals, and descriptions thereof are omitted. The characteristic configuration according to the third embodiment is that the motor 19 is a brushless motor. Therefore, the illustrated brushless motor 19 includes three-phase windings 19x, 19y, and 19z as stator coils. In the illustrated example, the windings 19x, 19y, and 19z are configured as Y connections.
[0037]
With respect to the brushless motor 19, the motor drive circuits 44a and 44b in the control device 22 are configured as a circuit for generating a three-phase alternating current. Accordingly, the motor drive circuits 44a and 44b have three output terminals for three-phase AC output. Based on any two combinations of the three output terminals of the motor drive circuit (1) 44a which is the first motor drive circuit section (first path), the windings (19x, 19y), (19y, 19z) and (19z, 19x) are supplied with motor current. Similarly, based on any two combinations of the three output terminals of the motor drive circuit (2) 44b which is the second motor drive circuit unit (second path), the windings (19x, 19y), Motor current is supplied to the energization routes (19y, 19z) and (19z, 19x). The selection of each operation of the motor drive circuit 44a and the motor drive circuit 44b is appropriately set as described in the first embodiment.
[0038]
Current sensors (52a-1 to 52a-3, 52b-1 to 52b) that detect motor currents in response to changes in the brushless motor 19 and the three-phase AC output motor drive circuits (1, 2) 44a, 44b. -3) and three F / S relays (46a-1 to 46a-3, 46b-1 to 46b-3).
[0039]
In the configuration of the control device 22 according to the third embodiment, when the assist motor is the brushless motor 19, an electrical connection portion from the steering torque detection unit 20 to the control device 22, a three-phase motor current output motor Since each of the motor drive circuit unit including the drive circuits 44a and 44b and the power supply path from the battery 25 to the motor drive circuits 44a and 44b is made into two paths (double) based on the parallel connection relationship, any location Even if a failure occurs, the electric power steering apparatus can be operated in the remaining path, and the system failure of the electric power steering apparatus can be prevented by providing the redundant system.
[0040]
In the above-described embodiment, the example of the electric power steering device is described as the steering device. However, it is needless to say that the technical idea of the present invention can be applied to other steering devices such as a steer-by-wire system.
[0041]
【The invention's effect】
As is apparent from the above description, according to the present invention, in a steering device such as an electric power steering device, a drive circuit for generating a motor current in the control device is provided in two paths, and the control device, the steering torque detector, and the control device Since the lines (signal lines and power lines) that connect the battery, the control device and the motor are duplicated, even if a failure occurs in the electrical connection or the electrical disconnection of the harness occurs, the drive circuit and harness in the remaining path will drive the motor. By performing the drive control, system down can be prevented, the system can be maintained, and system reliability can be maintained high. When the steering device is an electric power steering device, the assist of manual steering force can always be maintained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a wiring state inside a vehicle front end provided with a steering device having a redundant system according to the present invention.
FIG. 2 is a plan view showing a wiring state inside a vehicle provided with a steering device having a redundant system according to the present invention.
FIG. 3 is a block diagram showing an internal configuration of a control device.
FIG. 4 is a configuration diagram showing a first embodiment of a control device for a steering device according to the present invention.
FIG. 5 is a configuration diagram showing a second embodiment of the control device of the steering device according to the present invention.
FIG. 6 is a configuration diagram showing a third embodiment of the control device for the steering device according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vehicle 10 Electric power steering apparatus 11 Steering wheel 12 Steering shaft 15 Rack and pinion mechanism 19 Motor 19L, 19R Motor harness 20 Steering torque detection part 20L, 20R Torque sensor harness 22 Controller 25 Battery 25L, 25R Power harness 31 Target current determination Part

Claims (2)

Torque detection means for detecting steering torque, target current determination means for determining a motor current according to the steering torque output from the torque detection means, and a motor according to the motor current determined by the target current determination means In a steering apparatus including a drive circuit unit for supplying current to
The drive circuit unit has the same drive circuit of two paths,
And at least two motor harness with wiring through different locations of the vehicle each of the two torque sensor harness even without low, the one of the at least two power harness left side portion of the vehicle, the other A steering apparatus having a redundant system, wherein the steering system is wired along one right side portion . The number of the torque detecting means is one, and one of the at least two torque sensor harnesses connected to the torque detecting means is detoured forward from the rack shaft to the front of the vehicle to the torque detecting means. The steering apparatus having a redundant system according to claim 1, wherein the steering apparatus is wired.

Images