JP3803678B2 - Vehicle steering force correction device - Google Patents

Description

  The present invention relates to a vehicle steering force correction device.

A technical idea for correcting the steering force of a vehicle is already known. For example, in Patent Document 1 below, a yaw rate around a vertical axis passing through the center of gravity of a vehicle is detected, and a value different from an intended yaw rate is detected. Has been proposed that determines that a slip has occurred between the tire and the road surface and operates the steering force to prompt the driver to perform a correction operation.
Japanese Patent Laid-Open No. 3-16879

  Whether the yaw rate or lateral G is used, it is verified whether the amount of information is properly generated with respect to the input steering angle operated by the driver, and if there is a difference, the steering force is corrected to correct the input steering angle. The medium that prompts the driver to perform a correction operation is based on the so-called feedback concept. The concept of feedback is premised on the fact that the difference has already occurred. Therefore, the effect as a symptomatic treatment can be expected, but the occurrence of the difference cannot be prevented in advance.

In recent years, with the development of computers, sensors that can accurately grasp the current state of vehicles have been developed, and it is possible to grasp or predict the course deviation of a vehicle not only by lateral G but also by images, or close to the side rear It is possible to monitor other vehicles with ultrasonic waves, lasers, etc., and the collision that will occur when the driver tries to change the lane without knowing it like the technique described in Patent Document 2 below. Technology that predicts this has also appeared. In addition, a method for increasing the steering force by reducing the power assist force in a vehicle including a power steering device is also known, as in the technique of Patent Document 3 below.
Japanese Patent Laid-Open No. 4-19274 Japanese Patent Publication No.54-11171

  However, the technique described in Patent Document 2 described above only stops reducing the power assist force when another vehicle or the like is present in the turning direction, and does not correct the steering force beyond that. In other words, the state of the vehicle in the near future is predicted from the state quantity relating to the current driving state of the vehicle, the steering force is corrected to an appropriate one, and the driver performs corrective steering, and the behavior of the vehicle in the near future is determined by the driver. In the form of steering force, to reduce the risk of an accident occurring, in accordance with what the driver predicted, or in the form of steering force that may be encountered in the near future due to information that the driver overlooked There wasn't.

  Accordingly, the first object of the present invention is to predict the state of the vehicle in the near future from the state quantity related to the current vehicle running state, correct the steering force to an appropriate one based on the feedforward concept, and Let corrective steering be used to match the behavior of the vehicle in the near future to what the driver was expecting, or to identify the risk that the driver might have encountered in the near future because of information that the driver overlooked. An object of the present invention is to provide a steering force correction device for a vehicle that is provided in the above.

  Furthermore, as a result of predicting the state of the vehicle in the future, there may be a case where it is considered that, for example, turning to the right is less dangerous than going straight ahead. In such a case, it is desirable to provide the driver with the information by reducing the right steering force or increasing the left steering force.

  Accordingly, a second object of the present invention is to provide a vehicle steering force correction device that can provide prediction information to a driver by predicting the state of a future vehicle and changing the steering force left and right based on the predicted state. There is.

  Furthermore, as a result of predicting the state of the vehicle in the future, for example, when it is judged that turning to the right is less dangerous, simply reducing the right steering force and prompting the driver to turn right However, it is more effective to induce an avoidance action that actively turns to the right.

  Accordingly, it is a third object of the present invention to provide a vehicle steering force correction device that can actively encourage a driver to avoid a possible danger in the future.

  Furthermore, the present invention is not limited to a vehicle equipped with a power steering device, but is also applicable to a manual steering vehicle. However, when used in a vehicle equipped with a power steering device, there is an advantage that the device can be downsized.

  In a vehicle equipped with such a power steering device, as a method for determining the increase or decrease of the steering force, a method of increasing the steering force by reducing the amount of power assist, for example, pressure oil from a pump is used as a vehicle speed responsive power steering device. There are a technique realized by increasing the pressure level in the reaction chamber, such as a technique of increasing the steering force by letting it escape to the tank with a solenoid valve and a technique described in Patent Document 3 above. However, these methods focus on making the left and right steering forces equally heavy, and the purpose was exclusively to prevent excessive turning of the rudder at high speeds.

  If there is such a power steering device, as described above, if it is determined that, for example, steering to the right is more dangerous as a result of predicting the future of the vehicle, at least the right steering is performed. It is effective to increase the steering force by reducing the amount of power assist at this time. On the other hand, for example, when it is more preferable to perform corrective steering to the right, it is effective to reduce the steering force by increasing the amount of power assist at least during right steering. The driver will be prompted to perform corrective steering to the right. Of course, it can be considered that the power from the power source acts as a steering force independently of the steering of the driver, and the avoidance operation is positively induced.

  Accordingly, a fourth object of the present invention is to change the steering force left and right by adjusting the amount of power assist in a vehicle equipped with a power steering device, or to apply the steering force in a direction that actively causes an avoidance operation. It is an object of the present invention to provide a vehicle steering force correction device that can perform the above-described operation.

  Of course, the driver must be able to select straight or left / right steering at his / her will even in the case described above. This is because the driver does not always know the presence of a curve or an obstacle ahead. When the driver is aware of the situation ahead and chooses a course different from the curve, or plans to stop just before the obstacle, or avoids to the left and stops There is also a possibility.

  Accordingly, a fifth object of the present invention is to provide a vehicle steering force correction device having an override function in which driver steering is prioritized when the judgment of the driver does not coincide with the steering force output by the system or apparatus. Is to provide.

  Furthermore, as a result of predicting the future of the vehicle, it may be possible to predict a better result when steering is not performed on either side. For example, this is the case when there is another vehicle overtaking in any of the left and right lanes, and an obstacle is detected ahead. In such a case, it is desirable to increase the steering force on both the left and right sides to encourage the driver to go straight ahead, or at least to stay within his lane.

  Accordingly, a sixth object of the present invention is to provide a vehicle that can increase the steering force to the left and right according to the degree of the determination when it is determined that either the left or right steering is not preferable. The object is to provide a steering force correction device.

  Furthermore, in the case of a vehicle equipped with a power steering device, if the amount of power assist is simply adjusted to change the level of steering force, the maximum steering force is theoretically the same as that during manual steering. The minimum steering force can be realized only with a resistance of 0 that is turned with one little finger. However, assuming a situation where the reliability of the system is increased and the driver is unable to drive normally due to falling asleep or the like, it may be more appropriate for the system to judge the situation and actively perform steering.

  The concept of the self-driving car currently proposed is that the system actively steers and guides the car on the target course. In this way, in an autonomous driving vehicle that completely delegates driving to the system side at a certain point in time, there are some design methods, but humans have not recognized that authority has been delegated to the system side as above In some cases, no good technique has been proposed.

  In addition, if the system side can select the optimal course from the current car situation and the situation ahead and steer, and if this steering can be transmitted to the driver in the form of steering force, the driver will search for a point with less steering force. As a result, it is easier to follow the lane. Such a form has never been proposed as a better interface between systems and humans.

  In this case, as the steering force provided by the system is set larger, the vehicle automatically follows the lane even when the driver releases his hand from the steering wheel. By changing the degree of system intervention in an analog fashion, it is possible to “continuously” shift from collaborative work between humans and the system to fully automated driving. , Technology will be able to evolve.

  Accordingly, the seventh object of the present invention is that the driver can easily follow the lane when the control system calculates the optimum steering amount for traveling following the lane and the driver is also participating in the steering. The present invention proposes a vehicle steering force correction device that provides information to a driver via a steering force so that the vehicle can co-operate with a human.

  Further, an accompanying eighth object of the present invention is that it is possible to continuously change the rate at which the system and the person are involved in steering, and to shift to automatic driving without any human involvement depending on the setting of control parameters. An object of the present invention is to provide a vehicle steering force correction device.

  Further, if the technical contents of the above-mentioned Patent Document 1 exemplified as the prior art are examined carefully, it will be understood that the present invention cannot be realized by using the mechanism portion of the disclosed technique. The reason for this is that many power steering devices are mainly from the viewpoint of energy saving, but because so-called open center systems are used, hydraulic pressure to apply bias force is generated in principle unless the steering wheel is turned. Not to mention.

  Also, while operating the steering wheel, you can certainly see the generation of hydraulic pressure, and thus it seems that you can get the desired bias force, but you can not neglect the fact that the generated hydraulic level is proportional to the road reaction force . If the generated hydraulic pressure level is not constant, the bias force setting is unstable, and some stabilization technique may be required.

In the second embodiment disclosed in the publication, an electric power is used as an independent energy source without depending on an unstable hydraulic pressure level. In this example, the advantage that the bias force can be set with high accuracy can be recognized, but the following disadvantages can also be expected. That is,
(1) Since all the mechanisms for generating the bias force are incorporated in the rotating body, a slip ring that is inevitably lacking in reliability is required.
(2) Since all of the electromagnetic force generation mechanism is exposed to the hydraulic oil, and the electromagnetic force adsorbs a large amount of floating dust existing in the hydraulic oil, the smoothness of the operation is impaired. Thus, there is still a lot of room for improvement in the mechanism part.

  Accordingly, a ninth object of the present invention is to provide a vehicle steering force correction apparatus having a compact, easy to make and highly reliable structure.

  A further object of the present invention is to provide a vehicle steering force correction device that can easily reproduce the neutral point (straight-running state) of the steering system when the device starts operation.

In order to achieve the first to ninth objects described above, the vehicle steering force correction apparatus according to claim 1 includes an obstacle detection means for detecting an obstacle around the host vehicle, and the obstacle. A risk degree calculating means for calculating the degree of danger when steering in the direction in which the obstacle exists according to the output of the detecting means, a torque detecting means for detecting the direction and magnitude of the steering torque applied to the steering wheel, Support means for supporting at least a part of a necessary steering force based on a predetermined relationship from the output of the torque detection means, and steering that the support means should start to operate based on at least the output of the risk level calculation means A torque threshold value is calculated and compared with the output of the torque detection means, and the correction means is configured to change the predetermined relationship in accordance with the comparison result obtained .

  According to a second aspect of the present invention, the correction means is configured to reduce the amount of turning assistance in at least the direction in which the obstacle exists in accordance with the output of the risk degree calculation means.

According to claim 3, the vehicle has lane change detection means for detecting that the own vehicle has moved beyond the dividing line of the traveling lane of the own vehicle to the adjacent lane, and according to the output of the lane change detection means The function of the steering force correction means is stopped.

In order to achieve the above first to ninth objects, the vehicle steering force correction apparatus according to claim 4 includes an obstacle detection means for detecting an obstacle around the host vehicle, and the obstacle. In accordance with the output of the detection means, a risk calculation means for calculating the risk when steering in the direction in which the obstacle exists, a steering means for operating the steering wheel of the vehicle, and a reference in the traveling lane of the own vehicle a deviation detecting means for detecting a deviation from the line, and with consisting of biasing means for generating a steering torque to the steering means in response to outputs of said deviation detecting means of the risk calculation means, said deviation When the output of the detecting means is below a predetermined value, the function of the urging means is substantially stopped .

In order to achieve the first to ninth objects described above, the vehicle steering force correction apparatus according to claim 5 includes an obstacle detection means for detecting an obstacle around the host vehicle, and the obstacle. In accordance with the output of the detection means, a risk level calculation means for calculating a risk level when steering in the direction in which the obstacle exists, a steering means for operating the steering wheel of the vehicle, and an inclination of the own vehicle with respect to the traveling lane Direction detecting means for detecting, and biasing means for generating steering torque in the steering means in accordance with the output of the risk degree calculating means and the output of the direction detecting means , and further, the traveling lane of the host vehicle And a bias detecting means for detecting the deviation from the reference line, and the function of the biasing means is substantially stopped when the output of the bias detecting means is below a predetermined value .

According to a sixth aspect of the present invention, vehicle speed detection means for detecting the vehicle speed of the host vehicle is provided, and the function of the urging means is stopped according to the output of the vehicle speed detection means.

In order to achieve an object further associated with the ninth object described above, in claim 7 , a neutral point identifying means for identifying the neutral point of the left-right turning is further provided.

In Claim 1, the obstacle detection means for detecting obstacles around the host vehicle, and the risk of calculating the degree of danger when steering in the direction in which the obstacle exists according to the output of the obstacle detection means A degree calculating means, a torque detecting means for detecting the direction and magnitude of the steering torque applied to the steering wheel, and an assistance for assisting at least a part of the necessary steering force based on a predetermined relationship from the output of the torque detecting means And a steering torque threshold value at which the support means should start operation based on at least the output of the risk calculation means and compare it with the output of the torque detection means, and according to the comparison result thus obtained Since it is configured to include correction means for changing the predetermined relationship, the risk that the driver may encounter in the near future because of information that the driver has overlooked is the form of the steering force. It is possible to provide. In addition, the driver can be actively encouraged to avoid a possible danger in the future. Furthermore, by changing the amount of support in a vehicle equipped with a support device, the steering force can be changed from side to side, or an avoidance operation can be actively performed.

  In the vehicle steering force correction apparatus according to claim 2, the correction means is configured to reduce a steering assistance amount at least in the direction in which the obstacle exists in accordance with an output of the risk degree calculation means. Therefore, more accurate prediction information can be provided to the driver by predicting the state of the future vehicle and changing the steering force left and right based on the predicted state.

According to a third aspect of the present invention, there is provided a vehicle steering force correction apparatus comprising: lane change detection means for detecting that the own vehicle has moved to the adjacent lane beyond the lane marking of the traveling lane of the own vehicle; Since the function of the steering force correcting means is stopped according to the output of the means, it is possible to prevent returning to the previous lane after completing the lane change.

According to a fourth aspect of the present invention, there is an obstacle detection means for detecting obstacles around the own vehicle, and a risk for calculating a risk when the vehicle is steered in the direction in which the obstacle exists according to the output of the obstacle detection means. Degree calculating means, steering means for operating the steering wheel of the vehicle, bias detecting means for detecting a deviation from the reference line in the traveling lane of the host vehicle, and output of the risk calculating means and the bias detecting means Urging means for generating steering torque in response to the output of the steering means, and when the output of the bias detection means is below a predetermined value, the function of the urging means is substantially stopped. Since it is configured, the state of the vehicle in the near future is predicted from the state quantity related to the running state of the current vehicle, the steering force is corrected to an appropriate one based on the concept of feedforward, and the driver performs correction steering, Its near future The car behavior driver match to what was expected, or the risk that might be encountered in the near future because of the information that the driver had been overlooked can be provided in the form of a steering force. In addition, it is possible to provide prediction information to the driver by predicting the state of the future vehicle and changing the steering force on the left and right based on the predicted state, and actively urging the driver to avoid the potential danger in the future. be able to. Further, when the steering wheel is steered to the side where the following vehicle is present, even if the steering wheel is strongly pushed back to the original lane, the vehicle can be prevented from being pushed back to the opposite lane.

According to a fifth aspect of the present invention , there is an obstacle detection means for detecting obstacles around the host vehicle, and a risk for calculating the degree of danger when steering in the direction in which the obstacle exists according to the output of the obstacle detection means. According to the output of the degree calculation means, the steering means for operating the steering wheel of the vehicle, the direction detection means for detecting the inclination of the host vehicle with respect to the traveling lane, and the output of the risk calculation means and the output of the direction detection means And a bias detecting means for detecting a deviation from a reference line in the traveling lane of the own vehicle, and the output of the bias detecting means is a predetermined value. Since the function of the biasing means is substantially stopped when the value is less than or equal to the value , based on the concept of feedforward by predicting the state of the vehicle in the near future from the state quantity related to the current vehicle running state Suitable steering force To correct and let the driver perform corrective steering to match the behavior of the car in the near future to what the driver was expecting, or may encounter in the near future because of information that the driver overlooked There can be no danger in the form of steering force. In addition, it is possible to provide prediction information to the driver by predicting the state of the future vehicle and changing the steering force on the left and right based on the predicted state, and also actively urging the driver to avoid possible danger in the future. be able to. Further, when the steering wheel is steered to the side where the following vehicle is present, even if the steering wheel is strongly pushed back to the original lane, the vehicle can be prevented from being pushed back to the opposite lane.

In the vehicle steering force correction apparatus according to claim 6 , the vehicle speed detection means for detecting the vehicle speed of the host vehicle is provided, and the function of the urging means is stopped according to the output of the vehicle speed detection means. When the vehicle speed becomes extremely low, the correction function can be made unnecessary.

In the vehicle steering force correction device according to the seventh aspect of the present invention, since the neutral point identifying means for identifying the neutral point of the left and right steering is further provided, when the control unit is turned on to start the device In addition, the neutral point of the bias mechanism can be easily secured.

  The best mode for carrying out a vehicle steering force correcting apparatus according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is an explanatory perspective view generally showing a vehicle steering force correction apparatus according to a first embodiment of the present invention.

  As shown, this apparatus includes one CCD camera 10. The CCD camera 10 is fixed at the rear-mirror mounting position above the driver's seat and monocularly views the vehicle traveling direction. Reference numeral 12 denotes a radar unit from a millimeter wave radar, which consists of two front radars 12a attached to the front of the vehicle and six side radars 12b attached to the side of the vehicle. Detect three-dimensional obstacles such as other vehicles on the side and rear.

  A yaw rate sensor 14 is provided near the center of the vehicle compartment to detect the yaw rate (angular velocity) around the vertical axis of the center of gravity of the vehicle. Further, a vehicle speed sensor 16 composed of a reed switch is provided in the vicinity of the drive shaft (not shown) of the vehicle to detect the traveling speed of the vehicle.

  In the configuration shown in the figure, the steering mechanism (steering means) includes a column shaft 20 connected to the steering wheel 18 as shown in FIG. 2, and is carved at the tip of the pinion shaft 22 connected thereto. The pinion gear 24 meshes with the rack gear 28 of the rack shaft 26 to convert the rotational motion of the pinion shaft 22 into the reciprocating motion of the rack shaft 26. Both ends of the rack shaft 26 turn a steering wheel (front wheel) 32 via a tie rod (not shown) and a knuckle arm 30 to obtain a desired steering.

  Here, an electric motor (hereinafter referred to as “bias motor” or “motor”) 34 is provided in the vicinity of the column shaft 20. The motor output is transmitted to the column shaft 20 via the drive belt 36, and the pinion shaft 22 is rotationally driven to give a steering force. An encoder 38 is attached to the bias motor 34 and detects the steering angle input through the amount of rotation of the bias motor 34.

  The output of the sensor group described above in FIG. 1 is sent to the control unit 60.

  FIG. 3 is a block diagram showing details of the control unit 60.

  As illustrated, the control unit 60 includes three computers including a CPU 1, a CPU 2 and a CPU 3. The bias motor 34 is driven by the output of the motor amplifier 62 that receives the output of the CPU 2 and supplies current. Although not shown, the output torque of the motor may be amplified and transmitted via a reduction gear.

  The CPU 1 receives the output of the image processor 64 that detects and calculates the lane condition of the road ahead of the running vehicle by calculating and processing the image information obtained by the CCD camera 10 and the output of the front radar 12a. The output of the front obstacle evaluation device 66 that obtains position information about the front obstacle including other vehicles in the travel lane, the output of the yaw rate sensor 14, and the output of the vehicle speed sensor 16 are input. The CPU 1 makes an action plan and determination based on these outputs, determines a target route, determines a target steering angle θD, and outputs it to the CPU 2.

  The details are described in Japanese Patent Laid-Open Nos. 5-197423 and 7-81604 previously proposed by the present applicant, and will be briefly described below. Here, basically, a driving environment in which a driving lane (lane) such as an expressway is defined by a division line (white line) is assumed.

  First, a target point P is determined on the target route. Here, the target route is a center line M (virtual line, indicated by a broken line in FIG. 4) of the vehicle traveling lane divided by a lane division line (indicated by N in FIG. 4), and an appropriate route on the center line. A target point arrival yaw rate that causes the vehicle to reach the target point is determined using the forward position as the target point. Next, the angle deviation between the inclination angle of the vehicle at the target point and the inclination angle of the target route is obtained, the correction amount of the yaw rate required to reduce the angle deviation is obtained, and subtracted from the target point arrival yaw rate, and the difference is set as the target. The yaw rate is obtained, and the rudder angle that produces the target yaw rate is obtained as the target rudder angle θD.

  In addition, the CPU 1 also shows a deviation ΔL from the lane center line M (L: distance from the lane center line M to the lane center line M) and the own vehicle with respect to the lane center line M or the lane line N as shown in FIG. The direction of ΘV is also obtained.

  Further, the CPU 2 inputs the output of the side radar 12b that monitors other vehicles that are located in the left and right rear portions of the vehicle and that run around the host vehicle including the rear side (dead angle), and calculates the risk at the time of lane change. By inputting the output of the surrounding environment evaluation device 68 that evaluates the surrounding environment of the vehicle, the validity of the current steering angle is evaluated with reference to the degree of danger, and if the degree of danger is high, the lane change is prevented Therefore, a steering force correction value for increasing the steering force toward the right or left with a higher degree of danger is output to the bias motor 34.

  The CPU 1 also issues a command to the CPU 3 in charge of the vehicle speed plan to drive the brake pedal (not shown) in order to predict the collision from the obstacle information ahead and the speed of the host vehicle and automatically apply the braking. Although it is also configured to output to a braking actuator (not shown), since braking is not directly related to the present invention, the function of the CPU 3 will not be described. Further, as a subsystem not directly related to the present invention, a correction steering angle calculation and a steering angle correction circuit are prepared to directly control the steering angle, but this will not be described in the following description.

  The operation of the vehicle steering force correction apparatus according to the present invention will be described below with reference to the flowchart of FIG. This figure shows a control algorithm of the CPU 2 for causing the bias motor 34 to perform the above operation. The illustrated program is activated at predetermined time intervals.

  In the following, the detection parameters shown in the figure are first read in S1. Next, the process proceeds to S2, and the deviation ΔL from the lane center (line) M and the target steering angle θD, which are the outputs of the host CPU (CPU1), are read.

  Subsequently, the process proceeds to S3, where the read vehicle speed V is compared with a predetermined vehicle speed VTH (for example, 50 km / h). When the vehicle speed V is less than that, the program is immediately terminated. It is determined whether the deviation ΔL of the vehicle exceeds the width L to the lane center line, in other words, whether or not the vehicle has entered the left and right lanes. When the result is affirmative, the program is immediately terminated.

  To explain these, the vehicle speed V is compared with the predetermined vehicle speed VTH because the correction function is considered unnecessary when the vehicle speed is extremely low, and it is appropriate not to restart until the driver resets again. It is. This algorithm shows a case where the vehicle is traveling in the same lane. If it is determined in S4 that the lane has been changed to the adjacent lane, it will not be restarted until it is canceled and the driver is reset again. I did it.

  This is because, if this cancel function is simply omitted, the biasing force to return to the previous lane works even after the lane change is completed in the illustrated algorithm. Of course, when a lane change is made, it is also possible to automatically recognize a new lane and cause the above control to be performed inside the lane. ) It is necessary to recognize that N (FIG. 4) has been exceeded and to follow the next lane division line to the target.

  When the result in S4 is negative, the program proceeds to S5, and as shown in the figure, the target steering angle θD is multiplied by a gain (proportional constant) KBias to calculate the motor torque T of the bias motor 34, and the program proceeds to S6 to set the calculated torque T to the upper limit. Compared with the value T0, if it exceeds that, it is limited to the upper limit value T0.

  Subsequently, the process proceeds to S7, the motor supply current value is calculated so that the determined output torque is obtained, and the motor supply current value is output to the motor amplifier 62.

  In this embodiment, as described above, the first means comprising the CCD camera 10 and the image processing device 64 for detecting the lane condition of the road ahead and the CPU 1 for detecting the current positional relationship of the own vehicle with respect to the road lane. And a second means comprising a CPU 1 for calculating a steering amount (target steering angle θD) necessary for maintaining the positional relationship of the host vehicle with respect to the forward road lane from the outputs of the first and second means. A steering torque is generated in the steering means in response to the output of the steering means of the steering wheel 18 and the column shaft 20 for operating the steering wheel of the vehicle, and the output of the third means. The bias motor 34 and the biasing means S5 in FIG. 5 are configured.

  Further, the function of the biasing means is substantially stopped when the output of the bias detection means is below a predetermined value (S4).

  Furthermore, it has a vehicle speed detection means comprising a vehicle speed sensor 16 for detecting the vehicle speed of the host vehicle, and the function of the urging means is stopped according to the output of the vehicle speed detection means (S3).

  With the above configuration, the state of the vehicle in the near future is predicted based on the state amount related to the current vehicle running state, the steering force is corrected to an appropriate one based on the feed forward concept, and the driver performs corrective steering. Can match the driver's behavior in the near future to what the driver expected, or provide a risk in the form of steering force that may be encountered in the near future due to information the driver has missed It becomes.

  Furthermore, it is possible to provide prediction information to the driver by predicting the state of the future vehicle and changing the steering force on the left and right based on it, and actively avoiding the driver against possible future risks. Can be urged. In addition, in a vehicle equipped with a power steering device, the steering force can be changed left and right by increasing or decreasing the power assist amount, or an avoidance operation can be actively performed.

  Furthermore, the driver can drive by making full use of his senses, and at the same time, can perform optimum steering while referring to the output of this device. In other words, when the driver's judgment does not match the steering force output by the device, the driver has an override function that gives priority to steering, and when it is judged that the steering on either the left or right side is undesirable, The left and right steering forces can be increased according to the degree of determination.

  Furthermore, when the optimal steering amount is calculated for the device to follow the lane and the driver is also participating in steering, the steering force is applied so that the driver can easily steer along the lane. Information can be provided to the driver via the driver, and the ratio of the system and the human being involved in the steering can be changed continuously. It is possible to shift to automatic operation without any.

  The feature of this embodiment basically realizes the purpose by controlling the amount of steering force, so that the fail-safe operation at the time of failure of the bias mechanism according to this embodiment is basically guaranteed. In the unlikely event of a failure, only the change in steering force occurs as in the case of the conventional power steering device, and the most important function of the steering system that avoids obstacles is ensured to the end.

  The other features of this embodiment are also applicable to the embodiments described later, but can be realized simply by adding several devices with the existing system as the main, so there is no need to change the manufacturing facility significantly. Since it is compact and easy to make, the product obtained is highly reliable, structurally reliable, and inexpensive.

  In the first embodiment, the basic principle of the present invention is shown, and it is configured to be applicable to both a vehicle equipped with only a manual steering device and a vehicle equipped with a power steering device. Therefore, in the operation of the apparatus shown in FIG. 5, the detailed configuration described in the second embodiment and after, for example, the degree of risk calculated by the ambient environment evaluation device 68 is not taken into consideration. You can easily add them if necessary.

  FIG. 6 is a control circuit diagram of a hydraulic power steering apparatus showing a vehicle steering force correcting apparatus according to a second embodiment of the present invention. In the second and subsequent embodiments, the same reference numerals are used for the same members.

  In the first embodiment, it does not matter whether the vehicle has a manual steering device or a power steering device. In the second embodiment, the present invention is embodied in a vehicle having a hydraulic power steering device. Turned into. In addition, in the control circuit diagram of the hydraulic power steering apparatus of FIG. 6, the state which is steered to the left side is represented.

  More specifically, as shown in the figure, in a steering mechanism equipped with a hydraulic power steering device, the pinion shaft 22 is once supported by the pinion holder 44 and then rotated together with the holder to the case 42 as is well known. Bearing. When a steering torque is applied to the pinion shaft 22, the pinion holder pin (not shown) moves to the left and right to drive the four-way valve 46 from the neutral position to the left and right, and the pressure oil from the vane pump 48 is supplied to the power cylinder 50. A return path to the tank 52 is selectively connected to one chamber to the other chamber to obtain a desired power assist.

  In FIG. 6, a vane pump 48 driven by an engine pumps oil from a tank 52 and pressurizes it, and supplies it to a supply port of a 4-way valve 46 and two control valves for pressure control of a vehicle (a pressure reducing valve 70 and a variable throttle valve 72). Supply pressure oil. Reference numeral 74 is a known flow control valve for keeping the amount of oil supplied to the system constant even if the pump discharge amount fluctuates, and reference numeral 76 is a known pilot relief valve for regulating the maximum pressure. Indicates.

  As described above, the pinion gear 24 is once supported by the pinion holder 44 and then supported by the case 42 together with the holder. At this time, the bearing center X of the pinion gear 24 is higher than the bearing center Y of the holder 44 by ε. Designed with an offset. A holder pin (not shown) extends forward from the point A on the holder, and the tip of the pin is fitted in the slot B of the 4-way valve 46.

  Two pins 78 and 80 extend vertically from the four-way valve 46 in the figure and hold the plungers 84 and 86 of the reaction chamber 82. Two reaction chambers 82 are arranged at positions opposed to each other by 180 degrees across the four-way valve 46. However, for simplification of description, only one of the reaction chambers is displayed correctly, and the other reaction chamber is This is illustrated schematically above.

  The reaction chamber 82 receives the output pressure of the control valves 70 and 72 for responding to the vehicle speed, and the centering spring 88 presses the plungers 84 and 86 outward. The pressing force of the plungers 84 and 86 is stopped by the pins 78 and 80 and at the same time abuts against the wall on the case 42 side at the point C. When the four-way valve 46 is in the neutral position, the point C The gap between the pins and the gap between the pins are designed to be equal. Since these main components are disclosed in Japanese Patent Publication No. 62-10871 proposed by the present applicant, further explanation is omitted.

  Also in the second embodiment, a bias motor (electric motor) 90 similar to the bias motor 34 of the first embodiment is provided, and an arm 92 is attached to be rotatable about a point D, and the arm 92 is a spring. 94, it abuts on the four-way valve at the right end in the figure. That is, when the bias motor 90 is driven, the arm 92 moves to the left and right from the illustrated position, the movement displaces the spring 94, and acts on the four-way valve 46 as a kind of bias force.

  In order to restrict the overstroke of the arm 92, mechanical stoppers 96 and 98 are provided at appropriate positions. The stoppers 96 and 98 can prevent an excessive bias force from being applied to the 4-way valve 46.

  7 and 8 specifically show the structure of the bias motor 90 and its periphery.

  The bias motor 90 is coupled to the housing 102 coupled to the case 42 that houses the four-way valve 46 via a flange 104, and the output shaft 106 is integrated with the arm 92 via a screw. A slot 108 is formed in the other end of the arm 92, and a roller 110 is inserted into the slot.

  Both ends of the roller 110 are inserted into the guide grooves 112 and 114 on the case side, and the roller 110 linearly moves along the guide groove according to the swinging motion of the arm 92. The roller 110 is rotatably coupled to the spring support 115 at the center, and expands and contracts the spring 94 in conjunction with the movement of the arm 92. As described above, the range of the swinging motion of the arm 92 is limited to contact with the case-side stoppers 96 and 98. These mechanisms including the arm 92 are disposed in a space hydraulically sealed with a cover, and the interior is filled with oil substantially maintained at atmospheric pressure.

  A known encoder 116 for detecting the rotational position of the motor is also provided at the rear of the bias motor 90, and the motor is driven in accordance with a command based on the rotational angle detected by the encoder 116. Although not shown, the output torque of the motor may be amplified and transmitted via a reduction gear.

  Even when the vehicle operation is stopped and the control unit 60 is de-energized, the center of the arm 92 is centered so that the neutral point of the arm 92, that is, the neutral point of the left and right steering can be easily identified or reproduced. Springs 118 and 120 are prepared, and when a command is not sent to the motor, the spring is held at the neutral position shown in the drawing. As is apparent from the drawing, the structure of this spring is characterized in that an initial load is applied in the neutral position, and the arm is reliably returned to the neutral position by this initial load. Further, as clearly shown in FIG. 7, the output shaft of the motor 90 is separated from the working oil by an appropriate oil seal 122, and the working environment is kept good.

  Returning to the explanation of FIG. 6, the pressure reducing valve 70 controls the supply pressure from the pump to a constant low pressure out of the two control valves for vehicle speed response and sends it to the output port 70 a. The reduced output pressure acts on the left end of the lower variable throttle valve 72 in the drawing and presses the valve against the spring to the right. The variable throttle valve connects the reaction chamber 82 to the hydraulic pressure source slightly by a step provided at the position when the vehicle stops, and at the same time, the variable throttle valve is also slightly connected to the tank by another step. As a result, the pressure inside the reaction chamber 82 is substantially atmospheric pressure.

  The output port 70 a of the pressure reducing valve 70 is also connected to the hydraulic pump 132 via the throttle 130. Although not shown, the hydraulic pump 132 is configured to rotate in synchronization with the output shaft of the transmission. For this reason, there is a gear at the tip of the shaft of the rotor 132a, and a differential gear that is an output shaft of the transmission. 1 (both not shown).

  When the vehicle speed is 0, the rotor 132a of the hydraulic pump does not rotate, and thereafter, as the vehicle speed increases, the rotor 132a rotates at a speed proportional to the vehicle speed, and pumps oil from the right port to the left port. Thus, the amount of oil passing through the hydraulic pump 132 increases in proportion to the increase in vehicle speed. When the hydraulic pump 132 is stopped, the pressure on the left side in the drawing of the variable throttle valve 72 is controlled to the pressure set by the pressure reducing valve 70 and presses the valve 72 to the right. When the pressure is released, the pressure oil on the left side of the variable throttle valve 72 is pumped out by the pump. As a result, the pressure further decreases, and the variable throttle valve 72 starts to move from the illustrated state to the left by the action of the right spring.

  As a result, the higher the speed, the lower the sealing effect of the step on the side connecting the reaction chamber 82 to the hydraulic pressure source, and the higher the sealing effect on the side of the step connecting to the tank. Thus, the reaction chamber 82 is isolated from the tank during high-speed traveling, and complete connection with the hydraulic pressure source is completed. In this state, the reaction chamber 82 performs its original function and, as is well known, makes the driver feel a sense proportional to the road surface resistance.

  Next, the operation of the illustrated power steering apparatus will be described.

  Since no torque is applied to the steering wheel 18 in the neutral state, there is no force between the pinion gear 24 and the rack gear 28. The four-way valve 46 is in a neutral position by the action of a spring 88 inside the reaction chamber 82 and constitutes a so-called open center system in which the pressure oil sent from the hydraulic source is returned to the tank as it is. As a result, the pump supply pressure is substantially zero, and the pressures in the left and right chambers of the power cylinder 50 are both zero.

  Here, it is assumed that a left-turning torque indicated by a white arrow is applied to the steering wheel 18. The rack shaft 26 does not move because of road resistance acting on the front wheels. Since the rack shaft 26 does not move, the torque applied to the pinion gear 24 rolls on the rack gear 28 and tries to move to the left. It is the spring force inside the reaction chamber 82 that suppresses this movement. If the force to which the pinion gear 24 tries to move is smaller than this spring force, as a result, the four-way valve 46 continues to remain in the neutral position and power assist cannot be obtained.

  At this time, if the torque applied to the pinion gear 24 exceeds the road surface resistance value applied to the front wheels, the front wheels are steered without power assist. Such a situation corresponds to the case where the road surface on which the vehicle is placed is on slippery ice or the case where the vehicle is running and the reaction force from the road surface is small.

  If the torque applied to the steering wheel 18 is sufficiently large and the pinion gear 24 rolls left on the rack gear 28, the 4-way valve 46 pushes the spring in the reaction chamber and shifts to the right. As a result, as shown in the figure, the left chamber 50a of the power cylinder 50 is connected to the hydraulic source, the right chamber 50b is connected to the tank, and the rack shaft 26 is driven to the right by the resultant force of the pinion torque and the oil pressure. Thus, power assist can be obtained.

  Since the pressure of the hydraulic pressure source is introduced into the reaction chamber 82 during high speed traveling, the reaction chamber 82 is pushed back to the neutral position by an amount proportional to the increase of the pressure of the hydraulic pressure source. The degree of pressure introduction depends on how far the variable throttle valve 72 has moved, in other words, how high the vehicle speed is. The lower the vehicle speed is, the lower the ratio of the pressure of the hydraulic pressure source introduced into the reaction chamber 82 is. Therefore, the reaction force for returning the four-way valve 46 to the neutral position is weak. The description so far is provided for publicly known purposes and does not constitute a major part of the present invention. FIG. 9 shows the steering force characteristics exhibited by this apparatus.

  A case is considered in which the bias motor 90 is driven in FIG. 6 and the arm 92 is rotated by a certain angle in the clockwise direction from the illustrated position to exert a leftward bias force on the four-way valve 46.

  In this case, a larger pinion torque for driving the four-way valve 46 to the right is required. Therefore, it is difficult to obtain power assist, and the steering force at the time of left turning becomes heavy. Conversely, when considering the right turning, the 4-way valve moves to the left with a small pinion torque by the amount of the bias force, and power assist can be easily obtained during the right turning. Therefore, the steering force when the arm 92 rotates clockwise has a characteristic of left and right non-target, in which the right turning is light and the left turning is heavy.

  This is shown in FIG. It is clearly shown that the starting point of the power assist moves along the characteristic diagram of manual steering as the bias force increases. In this embodiment, since the bias force only acts on the centering spring 88 in the reaction chamber, the solid line and the dotted line only translate in the direction of the arrow on the straight line of the manual steering. The characteristics when the arm 92 rotates counterclockwise can be easily understood, and the right turning is heavy and the left turning is light.

  If the bias force is sufficiently large and exceeds the set value of the spring 88 in the reaction chamber, the characteristic is as shown by a one-dot chain line in FIG. That is, when the pinion input is zero, a negative steering force is generated that causes road resistance (rack output). In this state, when the driver releases his / her hand from the steering wheel, the steering wheel starts to rotate by itself and the steering is substantially performed.

  The steering amount is up to a position that balances the steering reaction force coming from the road surface, and the steering wheel does not cut any further. If the bias force is further increased, the steering angle of the front wheels can be further increased. Incidentally, the reaction force coming from the road surface during traveling is the aligning torque that returns the tire to the straight position based on the geometry of the suspension, as is well known.

  Although it has been clarified from the above explanation that the angle of the front wheel can be controlled by increasing / decreasing the bias force, the certainty cannot be guaranteed by the open loop control. Since it rotates, an encoder 126 for monitoring the rotation of the column shaft 20 is prepared. As will be described later, the CPU 2 uses a motor amplifier similar to that used in the first embodiment so that its output signal matches the target steering angle. Via the bias motor 90.

  Based on the above, the operation of the apparatus according to the second embodiment will be described with reference to the flowchart shown in FIG. FIG. 11 shows a control algorithm of the CPU 2 for causing the bias motor 90 to perform the above operation. However, for the sake of simplicity, it is assumed that the degree of danger is monitored only on the right side of the lane in which the vehicle is currently traveling. If the vehicle is traveling in the center lane and wants to consider the left and right risk levels, the same can be done by calculating the risk level for the left lane.

  In the following description, first, the illustrated detection parameters are read in S10. Here, the bias motor β indicates the actual displacement of the bias motor 90, and is obtained by converting the output of the encoder with appropriate characteristics. Next, the process proceeds to S12 and the illustrated output of the CPU 1 is read. Here, the risk αR calculated by the ambient environment evaluation device 68 will be briefly described.

The side radar 12b detects a relative distance D between the own vehicle and another vehicle traveling on the right (or left) lane. DD obtained by differentiating D means a relative speed of the other vehicle with respect to the own vehicle. If the sampling time instead of cumbersome differential processing is constant, it may be a relative velocity with the difference between D _t-1 and detected this time D _t previously detected. That may be _{dD = D t -D t-1} .

The risk degree α is defined by the following expression in this embodiment.
αR = A− (Kd × dDR) − (KD × DR)
Where αR ≧ 0, A: constant

  The above meaning means that when the relative speed dD is positive, the other vehicle is moving away from the own vehicle, so that the greater the dD, the lower the risk level. Conversely, when the vehicle is negative, it means that the other vehicle is approaching the vehicle, so the greater the absolute value, the higher the risk. The relative distance D is always a positive amount, but the greater the amount, the farther away, meaning that the degree of danger is low. Since a minus is not necessary for the concept of risk, the risk is defined as 0 even if the calculated value becomes negative. If the degree of risk on the left side is desired, the subscript R is replaced with L in the above formula.

  Even when the risk level is calculated for only one of the left and right lanes, if there is an obstacle such as a broken vehicle in the traveling vehicle lane, the risk level is calculated. Here, the definition of the risk level is expressed in the form of a simple linear function, but there are various application modifications such as squaring the amount related to the relative speed or distance, or using it as the denominator of the fraction.

  Subsequently, the process proceeds to S14, where the read vehicle speed V is compared with a predetermined vehicle speed VTH (for example, 50 km / h). When the vehicle speed V is less than that, the program is immediately terminated. It is determined whether the deviation ΔL of the vehicle exceeds the width L to the lane center line, in other words, whether or not the vehicle has entered the left and right lanes. When the result is affirmative, the program is immediately terminated.

  To explain these, the vehicle speed V is compared with the predetermined vehicle speed VTH because the correction function is considered unnecessary when the vehicle speed is extremely low, and it is appropriate not to restart until the driver resets again. It is. This algorithm shows a case where the vehicle travels within the same lane. If it is determined in S16 that a lane change has been made to the adjacent lane, it will not be restarted until it is canceled and the driver is reset again. I did it.

  This is because, if this cancel function is simply omitted, the biasing force to return to the previous lane works even after the lane change is completed in the illustrated algorithm. Of course, when a lane change is made, it is also possible to automatically recognize a new lane and cause the above control to be performed inside the lane. Recognizing that N (FIG. 4) has been exceeded, the next lane division line may be followed to the target.

  When the result in S16 is negative, the program proceeds to S18, and as shown in the figure, the target displacement (bias force) βD of the bias motor 90 is calculated by multiplying the target steering angle θD and the risk αR by gains (proportional constants) K1, K2, etc. . Thus, basically, the steering force obtained by multiplying the target steering angle θD by the gain is calculated, and the bias motor 90 is driven to obtain the steering force, and the arm 92 is displaced. In this embodiment, since the spring 94 for converting the arm displacement of the bias motor 90 into a steering force is linear, the target displacement βD to the bias motor 90 is an amount proportional to θD.

  Here, the gain K2 is corrected in accordance with the risk level αR. To explain this, when the risk level αR is output, the imminent following vehicle is present in the immediate vicinity, so that collision with this is avoided. For this purpose, it is desirable to set the gain K2 large to some extent so that there is no time delay. However, assuming that the gain K2 is increased, and if the steering wheel is steered to the side where the following vehicle is present in this state, if the target displacement (bias force) is calculated based on the risk αR, the original lane is strongly The vehicle is expected to be pushed back to the opposite lane because the return force is strong.

  Since this is inconvenient, the gain K2 is reduced to 0 at the center of the lane (ΔL ≦ 0) so that the above-mentioned side effects do not occur. That is, from the center of the lane to the side where the following vehicle is present, the gain K2 is increased in proportion to the distance ΔL from which the vehicle has deviated from the center, but the gain K2 is kept at 0 even if the vehicle is shifted to the opposite side. I did it.

  When such an emergency is required, it is required that the response of the device is as good as possible. For this reason, when the vehicle changes its orientation with respect to the lane center line or lane division line by the driver's steering and changes its direction by ΘV, the gain K2 is increased using the ΘV. Since ΘV is an early phenomenon for the vehicle to approach the next lane from now on, it can be expected to respond quickly. It is a kind of differential control. Of course, the same effect can be expected by using the rotational speed of the steering wheel instead of ΘV.

  Subsequently, the routine proceeds to S20, the torque T of the bias motor 90 is calculated by subtracting the current displacement β from the calculated target displacement βD and multiplied by the gain K0, and the procedure proceeds to S22 to compare the calculated torque T with the upper limit value T0. If it exceeds the upper limit, it is limited to the upper limit value T0. In the case of the second embodiment, the maximum stroke of the arm 92 is determined by the stoppers 96 and 98 even when an excessive torque is applied. This is for the purpose of preventing burning due to the continuous flow of water.

  Subsequently, the process proceeds to S24, where the motor supply current value is calculated so as to be the determined output torque, and is output to the motor amplifier. The supply current value is feedback controlled so that the difference between the output value of the encoder 116 and the target value decreases. Subsequently, the process proceeds to S26 and the above process is repeated until it is determined that the process is finished.

  In this embodiment, as described above, the first means comprising the CCD camera 10 and the image processing device 64 for detecting the lane condition of the road ahead and the CPU 1 for detecting the current positional relationship of the own vehicle with respect to the road lane. And a second means comprising a CPU 1 for calculating a steering amount (target steering angle θD) necessary for maintaining the positional relationship of the host vehicle with respect to the forward road lane from the outputs of the first and second means. A steering torque is generated in the steering means in response to the output of the steering means of the steering wheel 18 and the column shaft 20 for operating the steering wheel of the vehicle, and the output of the third means. The bias motor 90, the arm 92, the power cylinder 50, and the biasing means including S18 in FIG. 11 are configured.

  Furthermore, the first means for detecting the lane condition of the road ahead, the second means for detecting the current positional relationship of the own vehicle with respect to the road lane, and the first and second means The third means for calculating the steering amount necessary for maintaining the positional relationship of the host vehicle with respect to the front road lane from the output, the pinion gear 24 for detecting the direction and magnitude of the steering torque applied to the steering wheel, and the rack gear 28, a 4-way valve 46, etc., a torque detection means, a support means comprising a power cylinder 50 that supports at least a part of a necessary steering force based on a predetermined relationship from the output of the torque detection means, and the The correction means is composed of S18 in FIG. 11 for changing the predetermined relationship in accordance with the output of the third means.

Furthermore, the obstacle detection means comprising the radar 12 for detecting obstacles around the host vehicle and the degree of danger when steering in the direction in which the obstacle exists are calculated according to the output of the obstacle detection means. Necessary steering based on a predetermined relationship from the output of the torque detection means, the torque detection means for detecting the direction and the magnitude of the steering torque applied to the steering wheel, comprising the ambient environment evaluation device 68 A steering torque threshold value for starting the operation of the assisting means based on at least the output of the risk calculating means and the assisting means for assisting at least a part of the force, and comparing it with the output of the torque detecting means; Thus, the correction unit is configured to change the predetermined relationship in accordance with the comparison result obtained .

  Further, the obstacle detecting means for detecting obstacles around the vehicle, and the risk degree for calculating a risk degree when steering in the direction in which the obstacle exists according to the output of the obstacle detecting means. The calculation means, the steering means for operating the steering wheel of the vehicle, and the urging means for generating steering torque in the steering means in accordance with the output of the risk degree calculation means.

  Further, the obstacle detecting means for detecting obstacles around the vehicle, and the risk degree for calculating a risk degree when steering in the direction in which the obstacle exists according to the output of the obstacle detecting means. A calculating means; a steering means for operating a steering wheel of the vehicle; a bias detecting means comprising a CPU 1 for detecting a deviation ΔL from the reference line M in the traveling lane of the host vehicle; and an output of the risk calculating means And an urging means comprising S18 for causing the steering means to generate a steering torque in accordance with the output of the deviation detecting means.

  Further, the function of the biasing means is substantially stopped when the output of the bias detection means is below a predetermined value (S18).

  Further, the obstacle detecting means for detecting obstacles around the vehicle, and the risk degree for calculating a risk degree when steering in the direction in which the obstacle exists according to the output of the obstacle detecting means. A calculation means, a steering means for actuating a steering wheel of the vehicle, a direction detection means comprising a CPU 1 for detecting an inclination ΘV of the own vehicle with respect to the travel lane, an output of the risk calculation means, and the direction detection means The urging means is composed of S18 which causes the steering means to generate a steering torque according to the output.

  Furthermore, it has the deviation detecting means for detecting deviation from the reference line in the traveling lane of the own vehicle, and when the output of the deviation detecting means is a predetermined value 0 or less, the function of the urging means is substantially stopped. (S18).

  Furthermore, the vehicle has lane change detection means comprising a CPU 1 for detecting that the own vehicle has moved to the adjacent lane beyond the lane marking of the traveling lane of the own vehicle, and the steering force according to the output of the lane change detection means. The function of the correcting means is stopped (S16).

  Furthermore, it has a vehicle speed detection means comprising a vehicle speed sensor 16 for detecting the vehicle speed of the host vehicle, and the function of the urging means is stopped according to the output of the vehicle speed detection means (S14).

  With the above configuration, the state of the vehicle in the near future is predicted based on the state amount related to the current vehicle running state, the steering force is corrected to an appropriate one based on the feed forward concept, and the driver performs corrective steering. Can match the driver's behavior in the near future to what the driver expected, or provide a risk in the form of steering force that may be encountered in the near future due to information the driver has missed It becomes.

  Furthermore, it is possible to provide prediction information to the driver by predicting the state of the future vehicle and changing the steering force on the left and right based on it, and actively avoiding the driver against possible future risks. Can be urged. In addition, in a vehicle equipped with a power steering device, the steering force can be changed left and right by increasing or decreasing the power assist amount, or an avoidance operation can be actively performed.

  Furthermore, the driver can drive by making full use of his senses, and at the same time, can perform optimum steering while referring to the output of this device. In other words, when the driver's judgment does not match the steering force output by the device, the driver has an override function that gives priority to steering, and when it is judged that the steering on either the left or right side is undesirable, The left and right steering forces can be increased according to the degree of determination.

  Furthermore, when the optimal steering amount is calculated for the device to follow the lane and the driver is also participating in steering, the steering force is applied so that the driver can easily steer along the lane. Information can be provided to the driver via the driver, and the ratio of the system and the human being involved in the steering can be changed continuously. It is possible to shift to automatic operation without any.

  More specifically, this device generates a rack output even when the pinion input is 0 as shown by a one-dot chain line in FIG. 10, that is, it can also output a negative steering force that rotates the steering wheel. If the consciousness is awake, you can drive by relying on your five senses while referring to the negative steering force that is output, but if your consciousness is distracting, it will automatically be driven by the negative steering force that is output. Steering can prevent departure from the lane and avoid obstacles ahead.

  In this way, when the device actively guides the driver by the steering force, the lane seen from the driver can feel as if the lane center is running on a road with a recessed lane center like a bobsled. It is possible to provide a stable device in which the steering force is heavy regardless of whether it is steered to the left or right, that is, there is a virtual wall of the steering force and it is returned to the center.

  If Triba wants to change lanes, he can achieve his goal by giving the steering wheel enough steering force to overcome this virtual wall. Also, when the following vehicle is approaching by driving on the adjacent lane, the virtual wall that has not existed until now is built only on the side of the following vehicle, and the height of the wall depends on the degree of danger You can get the feeling of being high. Due to the appearance of this wall, the driver is pushed back due to the height of the wall even if he tries to steer to the side of the following vehicle, and as a result, a collision can be prevented. Of course, if the following vehicle moves away for some reason or diverts, the virtual wall also lowers its height and eventually disappears, so the driver should drive with normal feeling without any problem Can do.

  Also, when steering to the side where the following vehicle is, the response is good because the steering force is increased according to the direction of the vehicle relative to the lane marking, that is, the height of the virtual wall is increased. Thus, the wall can be constructed quickly. Conversely, the virtual wall is constructed only when approaching the side of the following vehicle from the center of the road, so when traveling in the center, you can travel without being aware of the wall. Even when pushed back to the virtual wall, the wall disappears if it returns to the center of the lane, and is not pushed back to the opposite lane.

  When pushed back more than anything, the direction of the vehicle's orientation ΘV with respect to the lane line becomes negative, and the height of the wall begins to decrease from the moment the vehicle changes its direction to the center of the lane, and the driver is aware of the wall. There is an advantage that it is not necessary.

  In addition, since the steering force can be determined independently on the left and right, it is possible to deal with it flexibly according to the left and right situations. Since the steering force bias force is also provided with mechanical stoppers 96 and 98, the bias force can be controlled to a certain predetermined value or less even when there is a discrepancy between the judgment on the device side and the judgment on the human side. Human behavior is given priority.

  Furthermore, it was comprised so that the neutral point identification means which consists of the springs 118 and 120 which identify the neutral point of a left-right steering could be provided. That is, since the arm 92 is held in the neutral position by the springs 118 and 120 having an initial load, the bias mechanism, that is, the bias is applied when the power is supplied to the CPU 1 and CPU 2 of the control unit 60 to start the apparatus. The neutral point of the motor 90 and the arm 92 can be easily secured, and it becomes easy to guarantee neutrality.

  The feature of the second embodiment is basically realized by controlling the amount of steering force, so that the fail-safe operation at the time of failure of the bias mechanism according to this embodiment is basically guaranteed. . In the unlikely event of a failure, only the change in steering force occurs as in the case of the conventional power steering device, and the most important function of the steering system that avoids obstacles is ensured to the end.

  The other features of this embodiment are also applicable to the embodiments described later, but can be realized simply by adding several devices with the existing system as the main, so there is no need to change the manufacturing facility significantly. Since it is compact and easy to make, the product obtained is highly reliable, structurally reliable, and inexpensive. In particular, when the power steering apparatus is used, the output of the bias motor 90 is sufficient, and the entire apparatus can be reduced in size. However, in other words, this means that the output of the bias motor 90 is relatively large, but the device according to the present invention can be realized even in a manual steering vehicle.

  Furthermore, the apparatus according to this embodiment performs the correction steering not only when the road structure is a straight line and the driver applies correction steering so that the driver follows the straight line, but also the road structure is curved and the driver follows the curve. In this case, a desired steering direction is calculated, and if the direction matches the steering direction currently performed by the driver, the steering force is not corrected, but if there is a mismatch, the direction and magnitude of the mismatch are not corrected. Accordingly, it is possible to reduce the steering force and prompt the driver to steer, or to push this forward to increase the steering force, thereby creating the virtual wall described above and semi-forcefully guiding the steering. The driver can also ignore this information and can easily follow the calculated course when following that information.

  FIG. 12 is a partial view of a hydraulic control circuit diagram similar to FIG. 6, showing a vehicle steering force correcting apparatus according to a third embodiment of the present invention. The other control circuits are basically the same as in FIG.

  In the third embodiment, the second pilot relief valve 140 and the servo motor 142 are provided in parallel with the pilot relief valve 76 of the vane pump 48, and the set value of the spring 144 for determining the set pressure level is made variable by the servo motor 142. I tried to control it. As a result of arranging these two pilot relief valves 76 and 140 in parallel, the maximum pressure of the hydraulic control circuit is restricted to the lower set pressure level.

  In order to change the set value of the spring 144 of the second pilot relief valve 140 by the rotational movement of the servo motor 142, the movement of the arm may be used as in the second embodiment. Structure 146 was used. That is, the female screw 148 is rotated with the rotation of the servo motor 142, and the male screw 150 meshing with the female screw is caused to linearly move.

  The female screw 148 is directly processed and provided at the center of the rotor of the servo motor 142. When the CPU 2 determines that it is inappropriate to steer in either the left or right direction, the CPU 2 drives the servo motor 142 to weaken the set value of the spring 144 of the second pilot relief valve 140 and increase the maximum supply pressure. Reduce. As a result, the amount of power assist obtained can be reduced and the steering force can be increased.

  The operation of the apparatus according to the third embodiment, specifically, the current value control to the servo motor 142 described above will be described with reference to the flowchart of FIG. 13. First, the process proceeds from S100 to S104 to S106, and the risk α Accordingly, the target position δD of the servo motor is calculated by subtracting and correcting the basic position δ0 by a product obtained by multiplying the risk α by a proportional constant K3 to reduce the set pressure of the relief valve 140.

  Subsequently, the process proceeds to S108, where the servo motor torque T is calculated by multiplying the difference between the target position δD and the current position δ by another gain K4, and the process proceeds to S110, where it is output to the motor amplifier. Repeat the above process. When it is determined in S104 that the vehicle speed V is less than the predetermined vehicle speed VTH, the above-described control is not executed as in the previous embodiment, so that the process proceeds to S114 and the servo motor position is restored to the basic position δ0.

  The characteristic diagram shown by the apparatus according to the third embodiment is as shown in FIG. The steering force after the relief valve 140 is actuated becomes a straight line parallel to the manual steering characteristic. Where the parallel straight line begins depends on how much the servo motor 142 weakens the spring 144. If the spring is completely weakened, the characteristic at that time coincides with the characteristic of manual steering.

  In the third embodiment, since the power assist amount is only reduced, automatic steering does not occur in principle. However, as a result of predicting the future of the vehicle, a better result may be predicted if steering is not performed on either the left or right side. For example, this is the case when there is another vehicle overtaking in any of the left and right lanes, and an obstacle is detected ahead. In such a case, by increasing the steering force on both the left and right sides, it is possible to prompt the driver to go straight ahead or at least stay in his lane.

  On the other hand, according to the third embodiment, since the relief valve 140 is a pilot valve, the output of the motor 142 that drives it to change the pressure level can be small, resulting in a small size and space. A device can be constructed. Since the installation location of the steering mechanism is generally an extremely narrow space, it is very important from a practical point of view that the apparatus can be gathered in a small size.

  FIG. 15 is a partial view of a hydraulic control circuit similar to FIG. 12, showing a vehicle steering force correcting apparatus according to a fourth embodiment of the present invention.

  In the third embodiment, the pressure level is controlled steplessly, but in the fourth embodiment, the solenoid valve 160 is used for on / off control. That is, when the CPU 2 determines that it is desirable to weaken or eliminate the power assist amount, the solenoid 162 is energized to open the poppet valve 164.

  As a result, in the figure of the flow control valve 74, the pressure oil in the right chamber 74a is partially released and drops, and the valve 74 moves to the right due to the differential pressure, and the discharge pressure of the pump is set to the suction side. return. The maximum pressure that can be used by the hydraulic control circuit is determined by the degree of the differential pressure obtained, and the limit of the power assist amount is determined. The determination of the differential pressure depends on the opening of the throttle 166 interposed. The characteristic diagram at this time is one of the straight lines in the characteristic curve of FIG. Depending on the choice of the throttle 166, the available pressure level will be substantially zero, at which time it matches the characteristics of the manual steering.

  The fourth embodiment also only changes the amount of power assist, and automatic steering does not occur, but the same effect as the third embodiment can be obtained by making the steering force heavier on both the left and right. Further, since the pilot valve is the same as in the third embodiment, there is an advantage that the structure of the valve itself can be reduced in size and the current consumption is reduced.

  FIG. 16 is a partial explanatory perspective view of an electric power steering apparatus showing a vehicle steering force correcting apparatus according to a fifth embodiment of the present invention. The apparatus according to the fifth embodiment uses an electric power steering apparatus mainly composed of an electric motor that does not use hydraulic pressure.

  In FIG. 16, a torque sensor (potentiometer) 170 that detects steering torque, an electric motor 172 that drives the column shaft 20 according to the output thereof, and a worm gear type deceleration that decelerates the output of the motor 172 and amplifies the torque. The machine 174 is integrated with the column shaft 20. In the figure, an ordinary rack and pinion type mechanical steering mechanism is provided on the lower side. Such an electric power steering apparatus is already known, and the structure itself is not directly related to the present invention.

  In the fifth embodiment, when torque is applied to the steering wheel 18, the torsion bar 176 is twisted, and the torsional displacement is converted into the vertical motion of the slider 178 via a cam (not shown). It detects with the sensor 170 (potentiometer). That is, when the steering wheel 18 has no torque, the slider 178 that has been kept straight is converted into a vertical displacement according to the direction and magnitude of the applied torque. The output signal of the torque sensor 170 is based on a straight line as shown in FIG.

  The CPU 2 inputs this signal and the vehicle speed signal, and outputs a current command value as indicated by a solid line in FIG. 18 to the electric motor 172 for power steering. Thus, the characteristics of the entire apparatus show a vehicle speed response type as shown by a solid line in FIG. Up to this point, it is known and does not constitute the main part of the present invention.

  FIG. 20 is a flowchart showing the operation of the apparatus according to the fifth embodiment. In the following description, detection parameters are read in S200. Here, the steering force (torque) τs is an output of the torque sensor 170, and takes a positive or negative value according to the left and right steering directions.

  Subsequently, the process proceeds to S202, and the risk degrees αR, αL and the target steering angle θD calculated by the CPU 1 are read. In the fifth embodiment, unlike the second embodiment, the risk α is calculated for the left and right lanes. That is, in the second embodiment, for example, the left steering is controlled to be heavy, and in the third and fourth embodiments, the left and right steering is controlled to be heavy, but in the fifth embodiment, both the left and right are controlled. Control independently.

  Subsequently, the process proceeds to S204, where the steering force threshold value τTH for starting the assist is corrected by the target steering angle θD and the left and right risk levels αR, αL, separately obtained in the left and right directions, and the process proceeds to S206, where the gain K5 is set to the basic value Multiply K0 by the difference between the ratio of the detected vehicle speed V and the predetermined value V1 and 1, that is, the gain K5 is calculated so as to decrease as the vehicle speed increases.

  Next, the routine proceeds to S208, where the maximum torque TMAX is calculated by subtracting the product of the vehicle speed V and the danger levels αR, αL from the upper limit value T0. Since the degree of risk is set separately for the left and right lanes, the maximum torque TMAX is also set separately for the left and right directions. Next, the routine proceeds to S210, where the absolute value of the detected steering force (torque) τs is compared with the assist start steering force threshold values τ0R, τ0L, respectively, and the detected steering force τs is one of the left and right threshold values τ0R, τ0L (calculated in S204) or When both are exceeded, the routine proceeds to S212, where the value γ is set to +1 or −1 according to the sign of the detected steering force, that is, the steering direction.

  Next, the routine proceeds to S214, where the motor torque TC is calculated by multiplying the difference between the detected steering force τs and the corrected threshold value τ0R or the product of τ0L and γ by the gain K5. Here, the threshold value τ0R or τ0L is multiplied by the value γ to become a value in either the left or right direction. Next, in S216, the absolute value of the motor torque TC calculated in step S216 is compared with the maximum torque TMAX calculated in step S208. When the maximum torque is exceeded, the maximum torque is calculated. More precisely, the maximum torque is multiplied by γ. Limited to either maximum torque.

  Next, in S218, the output torque T is output to the motor amplifier. In this way, the steering force is set according to θD and the risk degrees αR and αL, but the setting is made by adjusting the power assist amount. If it is determined in S210 that the absolute value of the detected steering force τs is equal to or less than the assist start threshold value τ0, the process proceeds to S220, and the motor torque TC is set to zero because no assist is performed. The above process is repeated until it is determined in S222 that the process is ended.

  As described above, the threshold value τTH of the steering force (torque) for starting the assist is corrected by the target steering angle θD and the left and right risk levels αR, αL, and the corrected threshold values τ0R, τ0L and the future (or present) are processed in the subsequent processing. ) Compare with the applied steering force τs and output a current value corresponding to the difference.

  The corrected threshold value τ0R or τ0L of the steering torque may be negative depending on the selection of the gain. When the threshold value is negative, steering occurs and automatic driving is possible even if no steering torque is input. Therefore, in the same way as in the previous embodiment, the same algorithm can be used in principle, from joint operation of humans and devices to complete automatic operation.

  The steering characteristic of the fifth embodiment will be described. In FIG. 18 and FIG. 19, the characteristic that is not corrected when the vehicle is traveling at a certain vehicle speed Va is the bold solid line and the characteristic that is corrected. Is indicated by a broken line E. The characteristic of the broken line E in the example shows a case where the steering force is controlled to be heavy, but of course, the steering force may be controlled lightly. Further, when the transition is made to the two-dot chain line G, the steering force becomes negative as described above, and the possibility of automatic driving is exhibited.

  According to the fifth embodiment, since it is possible to deal with software, unlike the second embodiment, the left and right assist amounts can be determined completely independently. Further, if the calculation process of the gain K5 is slightly modified, not only can the K5 be changed depending on the vehicle speed, but also can be easily changed according to the risk α, in which case the slope of the characteristic diagram of FIG. Can vary depending on the degree of danger.

For example, with the algorithm shown in the flow chart of FIG. 20, if the formula for calculating the gain K5 is changed to K5 = K0 (α0−αR) (α0−αL) × (1−V / V1) α0: a certain constant, the risk is high. As the gain K5 decreases, the power assist amount decreases.

  The state of the decrease is that the straight line slopes in FIG. 19 and approaches the straight line of the manual steering characteristic. In extreme cases, if either the left or right risk exceeds α0, K5 becomes negative, so the current flows backward and moves to the left over the manual steering line, realizing a heavier steering force than during manual steering. obtain.

  In the fifth embodiment, as described above, the first means comprising the CCD camera 10 and the image processing device 64 for detecting the lane condition of the road ahead and the CPU 1 for detecting the current positional relationship of the own vehicle with respect to the road lane. A second means comprising: a third means comprising a CPU 1 for calculating a steering amount necessary for maintaining the positional relationship of the host vehicle with respect to the forward road lane from the outputs of the first and second means; and a vehicle Steering means comprising a steering wheel 18 for actuating the steering wheel, and biasing means comprising an electric motor 172 for generating steering torque in response to the output of the third means. Configured.

  Furthermore, the first means for detecting the lane condition of the road ahead, the second means for detecting the current positional relationship of the own vehicle with respect to the road lane, and the first and second means From the third means for calculating the steering amount necessary for maintaining the positional relationship of the host vehicle with respect to the forward road lane from the output, and the torque sensor 170 for detecting the direction and magnitude of the steering torque τs applied to the steering wheel. According to the output of the torque detection means, the support means including the electric motor 172 that supports at least a part of the necessary steering force based on a predetermined relationship from the output of the torque detection means, and the output of the third means The correction means is composed of S214 in FIG. 20 for changing the predetermined relationship.

  Furthermore, when the third means outputs right or left turning, the support means is configured to increase the amount of support for the same direction turning (S204, S214).

  Further, when the third means outputs a right or left turning, the support means is configured to reduce or reduce the support amount of the opposite direction turning (S204, S214).

  Further, the predetermined relationship is that when the output τs of the torque detection means is smaller than the predetermined value τ0, the support amount is reduced or zero (S210), and the output of the torque detection means exceeds the predetermined value. In some cases, the support amount is determined in association with the steering torque τs (S214).

  Further, the correcting means is configured to change the predetermined value τ0 (S204).

  Further, the correction means adds the amount θD related to the output of the third means to the support amount of the support means, thereby energizing the steering force of the right or left turning (S204, S214). Configured.

  Furthermore, it comprises so that the control means (S206, S208) which controls the said required steering force may be provided.

  Furthermore, the predetermined relationship is configured such that when the torque τs applied to the steering wheel exceeds a predetermined predetermined value τ0, the support amount is set to a value proportional to the magnitude of the torque (S210, S214). In addition, the third means is configured to change the predetermined value to a negative value (S214).

Furthermore, the obstacle detection means comprising a side radar 12b for detecting obstacles around the vehicle and the degree of danger when steering in the direction in which the obstacle exists according to the output of the obstacle detection means. Necessary on the basis of a predetermined relationship from the output of the torque detection means, the risk detection means for detecting the direction and magnitude of the steering torque applied to the steering wheel, and the risk calculation means comprising the surrounding environment evaluation device 68 to calculate The assist means for assisting at least a part of the steering force, and at least an output of the torque detection means by calculating a steering torque threshold at which the support means should start operation based on the output of the risk calculation means. Comparing, and the correction means consisting of S204, S210, S214 that changes the predetermined relationship according to the comparison result obtained .

  Furthermore, the correction means is configured to reduce the amount of turning assistance in at least the direction in which the obstacle exists in accordance with the output of the risk degree calculation means (S214).

  With the above configuration, even in the fifth embodiment, the state of the vehicle in the near future is predicted from the state quantity related to the current vehicle traveling state, and the steering force is corrected to an appropriate one based on the concept of feedforward, Let the driver perform corrective steering to match the behavior of the vehicle in the near future to what the driver had predicted, or the risk that the driver might encounter in the near future because of information that the driver overlooked Can be provided in the form of

  Furthermore, it is possible to provide prediction information to the driver by predicting the state of the future vehicle and changing the steering force on the left and right based on it, and actively avoiding the driver against possible future risks. Can be urged. In addition, in a vehicle equipped with a power steering device, the steering force can be changed left and right by increasing or decreasing the power assist amount, or an avoidance operation can be actively performed.

  Furthermore, the driver can drive by making full use of his senses, and at the same time, can perform optimum steering while referring to the output of this device. In other words, when the driver's judgment does not match the steering force output by the device, the driver has an override function that gives priority to steering, and when it is judged that the steering on either the left or right side is undesirable, The left and right steering forces can be increased according to the degree of determination.

  Furthermore, when the optimal steering amount is calculated for the device to follow the lane and the driver is also participating in steering, the steering force is applied so that the driver can easily steer along the lane. Information can be provided to the driver via the driver, and the ratio of the system and the human being involved in the steering can be changed continuously. It is possible to shift to automatic operation without any.

  FIG. 21 is a flow chart similar to FIG. 20, showing a vehicle steering force correcting apparatus according to the sixth embodiment of the present invention.

  The device structure of the sixth embodiment is basically the same as that of the fifth embodiment, and only the control algorithm is different. In the sixth embodiment, the risk degree α is treated as the same on the left and right.

  Explaining below, after proceeding from S300 to S312 and calculating the motor torque TC in substantially the same procedure as in the fifth embodiment, proceed to S314 and subtracting the product of the risk α and the gain KT from the calculated motor torque TC. The absolute value is compared with the maximum torque TMAX, and if it is less than that, the value obtained by subtracting the product of the risk α and the gain KT from the calculated motor torque TC is used as the output torque T. The output torque T is defined as (determined to be positive or negative by multiplying by γ).

  That is, in the fifth embodiment, a bias is added to the output information of the sensor, but in the sixth embodiment, a bias is added to the output signal to the electric motor. The characteristic change at that time is shown by a broken line in FIGS. 22 and 23 as in the case of the fifth embodiment. Similarly to the fifth embodiment, in the sixth embodiment, when the characteristic indicated by the broken line is given, road resistance (rack output) is generated even if the steering force (pinion torque) is zero, and even a small bias signal causes a negative steering. Force, that is, automatic steering for rotating the steering wheel can be realized. The remaining configuration and effects are the same as in the fifth embodiment.

  In the sixth embodiment, the target steering angle θD may be read in S302, and the same steps as in S204 of FIG. 20 in the fifth embodiment may be provided. Further, the configuration of the fifth embodiment may be partially incorporated such that the risk degree α is set separately on the left and right.

  In the above-described embodiment, the CCD camera and the image processing apparatus are exemplified as means for knowing the road condition ahead. However, it can be easily understood that navigation information can be used in principle. The amount of information that the current navigation has is not yet sufficient, and the accuracy of the system that detects the current position is not so good, so the current road condition and the position and direction of the vehicle relative to the road, as well as the previous road condition, etc. Therefore, image recognition technology using a CCD camera is currently advantageous, and the disclosed embodiment adopts this method.

  At present, a technology for recognizing a lane by relying on this magnetism has been proposed mainly by the supervisory authority, embedding a magnetic sign on the road side instead of the environment recognition technology by image processing. Of course, if this technology becomes available, the present invention can be implemented without relying on expensive image processing technology.

  Moreover, although the highway was mentioned as an example of a traveling road, it is not restricted to it, If it is a road environment which can be recognized through a division line, it can implement also on a general road.

  In the above-described embodiments, the description has been made based on the vehicle equipped with the power steering. However, the power steering is not an essential condition, and the present invention can be applied to a manual type.

  Of the above-described embodiments, the torque sensors in the fifth and sixth embodiments are not limited to those illustrated as examples, and may have other structures.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory perspective view generally showing a vehicle steering force correction apparatus according to a first embodiment of the present invention; FIG. 2 is an explanatory top view schematically showing a steering mechanism of the apparatus of FIG. 1. It is a block diagram which shows the detail of the control unit of the apparatus of FIG. It is explanatory drawing which shows the parameter which CPU1 calculates in the block diagram of FIG. It is a flowchart which shows operation | movement of the apparatus of FIG. FIG. 6 is a hydraulic control circuit diagram when the apparatus of FIG. 1 is applied to a vehicle equipped with a hydraulic power steering device in a vehicle steering force correction apparatus according to a second embodiment of the present invention. FIG. 7 is an explanatory side view of a mechanism including a bias motor used in the vehicle steering force correction apparatus according to the second embodiment shown in the hydraulic control circuit diagram of FIG. 6. It is the VIII-VIII sectional view taken on the line of FIG. FIG. 7 is an explanatory diagram showing a conventional steering assist characteristic of a hydraulic power steering device used in a vehicle steering force correcting device according to a second embodiment of the present invention shown in FIG. 6. It is explanatory drawing which shows the steering force correction characteristic of the steering force correction apparatus of the vehicle which concerns on 2nd Example of this invention. It is a flowchart which shows operation | movement of the steering force correction apparatus of the vehicle which concerns on 2nd Example of this invention. FIG. 9 is a partial view of the hydraulic control circuit diagram of FIG. 6 showing a vehicle steering force correction apparatus according to a third embodiment of the present invention. It is a flowchart which shows operation | movement of the steering force correction apparatus of the vehicle which concerns on 3rd Example of this invention. It is explanatory drawing which shows the steering force correction characteristic of the steering force correction apparatus of the vehicle which concerns on 3rd Example of this invention. FIG. 13 is a partial diagram of a hydraulic control circuit diagram similar to FIG. 12 showing a vehicle steering force correction apparatus according to a fourth embodiment of the present invention. It is a partial explanation perspective view of the electric power steering device which shows the steering force amendment device of vehicles concerning the 5th example of this invention. It is explanatory drawing which shows the output characteristic of the torque sensor of the electric power steering apparatus shown in FIG. It is explanatory drawing which shows the electric current supply characteristic of the electric motor of the steering force correction apparatus of the vehicle which concerns on 5th Example of this invention. It is explanatory drawing which shows the steering force correction characteristic of the steering force correction apparatus of the vehicle which concerns on 5th Example of this invention. It is a flowchart which shows operation | movement of the steering force correction apparatus of the vehicle which concerns on 5th Example of this invention. It is a flowchart which shows operation | movement of the steering force correction apparatus of the vehicle which concerns on 6th Example of this invention. It is explanatory drawing which shows the electric current supply characteristic of the electric motor of the steering force correction apparatus of the vehicle which concerns on 6th Example of this invention. It is explanatory drawing which shows the steering force correction characteristic of the steering force correction apparatus of the vehicle which concerns on 6th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 CCD camera 12 Radar unit 14 Yaw rate sensor 16 Vehicle speed sensor 18 Steering wheel 20 Column shaft 22 Pinion shaft 24 Pinion gear 26 Rack shaft 28 Rack gear 32 Steering wheel (front wheel)
34 Electric motor (bias motor)
46 Four-way valve 50 Power cylinder 60 Control unit 64 Image processing device 66 Front obstacle evaluation device 68 Ambient environment evaluation device 70 Control valve (pressure reducing valve)
72 Control valve (variable throttle valve)
76,140 Pilot relief valve 82 Reaction chamber 84,86 Plunger 88 Spring 90 Electric motor (bias motor)
92 Arm 94 Spring 116 Encoder 118, 112 Spring 132 Hydraulic pump 142 Servo motor 146 Screw structure 160 Solenoid valve 170 Torque sensor 172 Electric motor

Claims (7)

Obstacle detection means for detecting obstacles around the host vehicle, risk degree calculation means for calculating the degree of danger when steering in the direction in which the obstacle exists according to the output of the obstacle detection means, and steering Torque detecting means for detecting the direction and magnitude of the steering torque applied to the wheel, support means for assisting at least part of the necessary steering force based on a predetermined relationship from the output of the torque detecting means, and at least the above Based on the output of the risk level calculation means, the assist means calculates a steering torque threshold value to start the operation, compares it with the output of the torque detection means, and changes the predetermined relationship according to the obtained comparison result. A vehicle steering force correction device characterized by comprising:   2. The vehicle steering according to claim 1, wherein the correction unit is configured to reduce a steering assistance amount at least in a direction in which the obstacle exists in accordance with an output of the risk degree calculation unit. Force correction device. It has a lane change detecting means for detecting that the own vehicle has moved beyond the lane marking of the own vehicle to the adjacent lane, and functions as a steering force correcting means according to the output of the lane change detecting means. 3. The vehicle steering force correction device according to claim 1, wherein the vehicle steering force correction device is configured to be stopped. Obstacle detection means for detecting obstacles around the vehicle, risk calculation means for calculating the risk when steering in the direction in which the obstacle exists according to the output of the obstacle detection means, and vehicle According to the steering means for operating the steering wheel, the deviation detecting means for detecting the deviation from the reference line in the traveling lane of the host vehicle, and the output of the risk calculating means and the output of the deviation detecting means And a biasing means for generating a steering torque in the steering means, and the function of the biasing means is substantially stopped when the output of the bias detection means is below a predetermined value. A vehicle steering force correction device. Obstacle detection means for detecting obstacles around the vehicle, risk calculation means for calculating the risk when steering in the direction in which the obstacle exists according to the output of the obstacle detection means, and vehicle Steering means for operating the steering wheel, direction detecting means for detecting the inclination of the vehicle with respect to the traveling lane, steering to the steering means in accordance with the output of the risk degree calculating means and the output of the direction detecting means And a bias detecting means for detecting a deviation from a reference line in the traveling lane of the own vehicle, and when the output of the bias detecting means is equal to or less than a predetermined value, A steering force correction apparatus for a vehicle, characterized in that the function of the urging means is substantially stopped . 6. The vehicle steering system according to claim 4 , further comprising vehicle speed detecting means for detecting a vehicle speed of the host vehicle, wherein the function of the urging means is stopped according to the output of the vehicle speed detecting means. Force correction device. The vehicle steering force correction device according to any one of claims 1 to 6 , further comprising neutral point identification means for identifying a neutral point of left and right turning.

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