Vehicle brake force control system

Abstract

Vehicle brake force control device (20) comprising the following: a stopping brake force control unit (202) that individually controls the braking forces of a steered wheel (51, 52) and a non-steered wheel (53, 54) during deceleration of a vehicle; and a pre-detection unit (203) that detects steering in advance while the vehicle is stationary, wherein The stop-brake force control unit (202) then, when steering in a stopped state of the vehicle is detected in advance by the pre-detection unit (203), performs a brake force minimization control in order to reduce the braking force of the steering wheel (51, 52) such that it is less than the braking force during normal braking, wherein the stopping brake force control unit (202) does not execute the brake force minimization control when a vehicle condition meets a predefined predefined prohibition condition, and the specified prohibition condition includes a case in which the vehicle has skidded, whereby Based on a difference in wheel speed between the steering wheels and the non-steering wheels, it is determined whether the vehicle has skidded.

Description

Technical field

[0001] The present invention relates to a brake force control device that individually controls the braking forces of steered wheels and non-steered wheels during the deceleration of a vehicle. Technical background

[0002] A driving mode used to steer a stationary vehicle is called steady-state steering. This mode allows for a turn with a minimal turning radius. Furthermore, steady-state steering can keep the turning radius constant during the maneuver. Steady-state steering has traditionally been used by many drivers because it is sometimes necessary when turning a vehicle in tight spaces and simplifies the vehicle's path. Similarly, in self-steering systems, steady-state steering remains an important driving mode due to its necessity in confined spaces and its ability to simplify the operating algorithm.

[0003] When steering from a stationary position, the steering wheel rotates around a kingpin axis by a steering angle. The total drag of a tire on the steering wheel is greater when the tire is rotated around the kingpin axis than when the tire is rotated around the tire's contact patch center if there is a distance between the kingpin axis and the tire's contact patch center, known as the scrub radius. The scrub radius is determined by a positional relationship between the kingpin axis and the wheel. Since a steering force at the time of steering can generally be smaller, and a force applied by a steering device absorbed by the ground can be reduced when the scrub radius is smaller, the kingpin axis is often designed to be as close as possible to the wheel's center.However, due to various limitations of a suspension system, steering system, power transmission system, and the like, the steering roll radius often cannot be designed to be small.

[0004] While the total drag of the tire during steady-state steering is greater when the scrub radius is large, here the tire is not always dragged during steady-state steering, and a tension against the steering force accumulates as twisting of each part of the vehicle, such as the tire, a braking device, the suspension device, or the steering device, within a range that does not exceed the frictional force between the tire and the ground. This twisting is relieved when the vehicle begins to move. However, even when stationary, twisting in one circumferential direction of the scrub radius can be relieved by releasing the brakes through the braking device to allow rotation of the steering wheel. For example, PTL 1 to PTL 3 disclose methods for releasing the brakes of a steering wheel during steady-state steering.

[0005] PTL 1 discloses a method for releasing a braking force of a steering wheel when a steering operation is detected in a stopped state of a vehicle.

[0006] PTL 2 discloses a method for detecting the intention of an occupant or the commencement of a movement of a vehicle and for restoring braking force after the braking force of a steering wheel has been released similarly to PTL 1.

[0007] PTL 3 discloses a method for preventing the application of a control mechanism to release the braking force of a steerable wheel, similar to PTL 1 or PTL 2, when a gradient in the road surface is detected. PTL 4 relates to a vehicle steering system with a steering device by which a steering force can be applied to the steerable wheel or wheels of a vehicle. The steering device is designed to interact with a control unit for the vehicle's service brake such that, when the service brake is applied and a steering force is applied, the braking force on the steerable wheel or wheels can be reduced or is reduced. Alternatively, when the service brake is applied and a steering force is applied, the service brake can be deactivated or is deactivated with respect to the steerable wheel or wheels.PTL 5 relates to a method for reducing the steering torque of a motor vehicle in a driving situation in which the vehicle is being braked and steered simultaneously. List of prior art patent literature PTL 1: JP 07-257336 A PTL 2: JP 2008-094117 A PTL 3: JP 2014-015082 A PTL 4: DE 10 2010 046 472 A1 PTL 5: DE 10 2009 055 059 A1 Summary of the invention: Technical problem

[0008] However, in all PTL 1 to PTL 3, a control is performed to minimize the braking force after steering operation has been detected. If the braking force minimization control is initiated in this way after the detection of steady steering, it will not function during a control delay period due to a delay between the detection margin and the control initiation time required for the braking force minimization control to begin. In particular, if the steering speed is high, the steering force amount during the control delay period will be large. Furthermore, in such a situation, where the steering force amount has already occurred, the subsequent execution of the braking force minimization control can cause abnormal noises and vehicle rocking due to the release of already accumulated tension.Meanwhile, the detection margin is needed to prevent a faulty detection of a control, and there is a performance limit to the device in the time required for the brake force minimization control.

[0009] The present invention was made with regard to the problem described above, and it is an object of the present invention to provide a brake force control device that can prevent the occurrence of abnormal noises and rocking of a vehicle when minimizing a braking force of a steering wheel, while reducing a steering load during steady steering in order to reduce a load on a steering device, and can prevent a stress build-up due to steady steering in order to reduce loads on the tire, a suspension device and the steering device. Solution to the problem

[0010] The aforementioned problem is solved by the invention according to the subject matter of claim 1. The dependent claims contain preferred embodiments of the invention. In particular, the present invention comprises a stopping brake force control unit that individually controls the braking forces of a steered wheel and a non-steering wheel during deceleration of a vehicle, and a pre-detection unit that detects steering in advance when the vehicle is stationary, wherein, when steering in advance is detected by the pre-detection unit, the stopping brake force control unit then performs a braking force minimization control to reduce the braking force of the steered wheel such that it is less than the braking force during normal braking.

[0011] The system detects steering (steady steering) in advance while the vehicle is stationary. Brake force minimization control is then executed before steady steering begins. This reduces the braking forces on the steering wheels to a level lower than those experienced during normal braking, thus reducing the steering load during steady steering and the stress on the steering system. Furthermore, it prevents stress buildup due to steady steering, thereby reducing the load on the tires, suspension, and steering components. Additionally, minimizing braking forces on the steering wheels also prevents stress buildup in the tires, suspension, and steering system. Advantageous effects of the invention

[0012] According to the present invention, the occurrence of anomalous noises and rocking of a vehicle can be prevented by minimizing braking forces of steering wheels, while reducing steering load during steady steering, reducing the load on a steering device, and reducing stress accumulation due to steady steering, thereby reducing loads on the tire, suspension device, and steering device. Brief description of the drawings [ Fig. 1] Fig. Figure 1 is an overall configuration diagram that represents an example of a brake force control system which includes a brake force control device according to a first embodiment of the present invention. [ Fig. 2] Fig. Figure 2 is a control block diagram representing a control configuration of the brake force control device according to the first embodiment of the present invention. [ Fig. 3] Fig. Figure 3 is a flowchart illustrating the brake force minimization control in the first embodiment of the present invention. [ Fig. 4] Fig. Figure 4 is a time diagram illustrating an example of a change in vehicle speed and brake pressure when the stop-time brake force minimization control is implemented in the first embodiment of the present invention. [ Fig. 5] Fig. Figure 5 is a time diagram that provides a further example of a change in vehicle speed and brake pressure when the stop-time brake force minimization control is implemented in the first embodiment of the present invention. [ Fig. 6] Fig. Figure 6 is a time diagram illustrating an example of a change in vehicle speed and brake pressure when the pre-stop braking force minimization control is implemented in the first embodiment of the present invention. [ Fig. 7] Fig. Figure 7 is a time diagram that provides a further example of a change in vehicle speed and brake pressure when the pre-stop braking force minimization control is implemented in the first embodiment of the present invention. [ Fig. 8] Fig. Figure 8 is a control block diagram to describe an example of a given precondition for detecting stationary steering in advance. [ Fig. 9] Fig. Figure 9 is a diagram that illustrates an example of a given precondition for detecting stationary steering in advance. [ Fig. 10] Fig. Figure 10 is a diagram that illustrates an example of a given precondition for detecting stationary steering in advance. [ Fig. 11] Fig. Figure 11 is a diagram that illustrates an example of a given precondition for detecting stationary steering in advance. [ Fig. 12] Fig. Figure 12 is a diagram that presents an example of a given precondition for detecting stationary steering in advance. [ Fig. 13] Fig. Figure 13 is a diagram that shows an example of a given prohibition condition for prohibiting the brake force minimization control. [ Fig. 14] Fig. Figure 14 is a diagram that shows an example of a given prohibition condition for prohibiting the brake force minimization control. [ Fig. 15] Fig. Figure 15 is a diagram that shows an example of a given prohibition condition for prohibiting the brake force minimization control. [ Fig. 16] Fig. Figure 16 is a diagram that presents an example of a given prohibition condition for prohibiting the brake force minimization control. [ Fig. 17] Fig. Figure 17 is a diagram that shows an example of a given prohibition condition for prohibiting the brake force minimization control. [ Fig. 18] Fig. Figure 18 is a control block diagram representing a brake force control device according to a second embodiment of the present invention. [ Fig. 19] Fig. Figure 19 is a flowchart illustrating the brake force minimization control in the second embodiment of the present invention. Description of the embodiments

[0013] Embodiments of the present invention are described below with reference to the drawings. It should be noted that in the drawings, components or elements that have the same effect or function are given the same reference numeral, and redundant explanations are omitted where appropriate. First embodiment

[0014] In the present embodiment, a case is assumed in which an occupant operates a vehicle based on their own intention, and a case in which the occupant operates the vehicle while receiving some assistance from the vehicle side. A brake force control device according to the present embodiment performs a control to reduce braking forces from steered wheels such that they are less than the braking forces during normal braking (hereinafter referred to as "brake force minimization control") when steady steering is detected in advance based on a state of the vehicle and it is determined that no problem exists if such control is performed.

[0015] Fig. Figure 1 is an overall configuration diagram that illustrates an example of a brake force control system comprising a brake force control device according to a first embodiment of the present invention. Fig. Figure 1 includes a brake force control system comprising a master cylinder 10, an electronic ABS / ESC control unit (ECU) 20 as a brake force control device that individually controls the braking forces of steered wheels 51 and 52 and non-steered wheels 53 and 54 during vehicle deceleration, a brake actuator 30, a power steering device 40, and wheel speed sensors 61 to 64 as its main components. The master cylinder 10 can generate master cylinder pressure when an occupant depresses a brake pedal (not shown). The brake force control device 20 controls the brake actuator 30 to adjust the brake pressure of each of the vehicle's wheels 51 to 54 based on the master cylinder pressure, thereby individually adjusting the braking force of each of the wheels 51 to 54. It should be noted that the brake actuator 30 can increase or decrease the brake pressure of each of the wheels 51 to 54, even if the master cylinder pressure is not generated.The wheel speed sensors 61 to 64 can generate signal waveforms according to the rotational speeds of the wheels 51 to 54. The brake force control unit 20 can measure the vehicle speed based on the signal waveforms generated by the wheel speed sensors 61 to 64. The steering assistance unit 40 can assist the steering effort based on the occupant's steering attention.

[0016] Fig. Figure 2 is a control block diagram that represents a control configuration of the brake force control device 20. Fig. 2 The brake force control unit 20 contains an ABS / ESC control unit 201, a stopping brake force control unit 202 and a pre-detection unit 203 as basic components and controls the brake actuator 30 on the basis of signals input from the wheel speed sensors 61 to 64 and the like.

[0017] The ABS / ESC control unit 201 is a control block mounted in the brake force control unit 20 and controls the brake actuator 30. Furthermore, the ABS / ESC control unit 201 receives signals from the wheel speed sensors 61 to 64 and generates a vehicle speed signal.

[0018] The pre-detection unit 203 reads information from each part of the vehicle according to a pre-detection procedure and controls the stopping brake force control unit 202 based on a detection result. The pre-detection unit 203 can be mounted in the brake force control unit 20 or can be mounted on another control unit.

[0019] The stopping brake force control unit 202 controls the ABS / ESC control unit 201 based on the signal from the pre-detection unit 203 and the vehicle speed signal from the ABS / ESC control unit 201. The stopping brake force control unit 202 can be mounted in the brake force control device 20 or in another control device. The input from the stopping brake force control unit 202 to the ABS / ESC control unit 201 is, for example, a signal that sets an upper limit for the brake pressure of each of the wheels 51 to 54. The braking forces of the steered wheels 51 to 52 can be minimized by setting a value lower than the upper limit for the brake pressures of the steered wheels 51 and 52. Furthermore, this input is, for example, a signal that sets an increase / decrease pressure value for the brake pressure of each of the wheels 51 to 54.The braking force of the entire vehicle can be obtained by specifying a decrease in pressure in the steering wheels 51 and 52 and a decrease in pressure in the non-steering wheels 53 and 54. This is effective when the braking forces of the steering wheels 51 and 52 are minimized, for example, on a road with a gradient.

[0020] Fig. Figure 3 is a flowchart illustrating the brake force minimization control in the present embodiment. The control shown in this flowchart is always executed by the stopping brake force control unit 202. The steps comprising this flowchart are described sequentially below.

[0021] First, based on a vehicle speed signal measured by the wheel speed sensors 61 to 64, it is determined (step S101) whether the vehicle is stopped.

[0022] If step S101 determines that the vehicle is stopped (YES), step S102 determines whether stationary steering in a currently stopped state will be detected in advance by the pre-detection unit 203. Here, the pre-detection unit 203 detects stationary steering in advance if the vehicle's state meets a predefined precondition. It should be noted that multiple predefined preconditions can be applied and combined using an AND or OR condition.

[0023] If step S102 determines that stationary steering is not detected in advance in the current stopped state (NO), one control action is executed (step S103) and the processing returns to step S101. Here, the normal control action is to adjust the brake pressure of each of the wheels 51 to 54 according to an application of the brake pedal by the occupant.

[0024] If step S102 determines that stationary steering is detected in advance in the current stopped state, step S104 determines whether a reduction in braking force of the steering wheels 51 and 52 is permitted. Whether the reduction in braking force of the steering wheels 51 and 52 is permitted is determined based on whether the vehicle's condition does not meet a predefined prohibition condition. It should be noted that multiple predefined prohibition conditions can be applied and that the prohibition conditions can be combined under an AND or an OR condition.

[0025] If step S104 determines that brake force minimization of the steered wheels 51 and 52 is not permitted (NO), normal control is executed (step 103) and processing returns to step S101. Conversely, if it determines that brake force minimization of the steered wheels 51 and 52 is permitted (YES), a stop-time brake force minimization control is executed (step S105) and processing returns to step S101.

[0026] If step S101 determines that the vehicle is not stopped (NO), step S106 determines whether the vehicle is braking and its speed is below a predetermined level. If step S106 determines that the vehicle is not braking or that its speed is equal to or greater than a predetermined level (NO), normal control is executed (step S108), and processing returns to step S101. Conversely, if step S107 determines that the vehicle is braking and its speed is below a predetermined level (YES), it determines whether the stationary steering in the next stopped state will be detected in advance by the pre-detection unit 203.Here, the pre-detection unit 203 detects stationary steering in advance in the next stopped state if the vehicle's state fulfills a predefined precondition. It should be noted that multiple predefined preconditions can be applied and that these preconditions can be combined using an AND or an OR condition.

[0027] If step S107 determines that steady-state steering is not detected in advance in the next stopped state (NO), normal control is executed (step S108) and processing returns to step S101. Conversely, if step S109 determines that steady-state steering is detected in advance in the next stopped state (YES), it is determined whether brake force minimization of the steering wheels 51 and 52 is permitted immediately before stopping. Here, based on whether a predefined prohibition condition is met, it is determined whether brake force minimization of the steering wheels 51 and 52 is permitted immediately before stopping. It should be noted that multiple predefined prohibition conditions can be applied and that the prohibition conditions can be combined using an AND or OR condition.

[0028] If step S109 determines that brake force minimization of the steered wheels 51 and 52 is not permitted immediately before coming to a complete stop (NO), normal control is executed (step S108) and processing returns to step S101. Conversely, if it determines that brake force minimization of the steered wheels 51 and 52 is permitted immediately before coming to a complete stop (YES), pre-stop brake force minimization control is executed (step S110) and processing returns to step S101.

[0029] Fig. Figure 4 is a time graph illustrating an example of a change in vehicle speed and brake pressure when the stop-time brake force minimization control (step S105 in Fig. 3) is executed. In the example that is in Fig. As shown in Figure 4, steady-state steering is detected in advance before or after the vehicle has stopped, the brake pressures of the steering wheels 51 and 52 are reduced so that they are lower than the brake pressures during normal braking after the vehicle has stopped, and the steering load during steady-state steering is reduced.

[0030] Fig. Figure 5 is a time graph that shows another example of a change in vehicle speed and brake pressure when the stop-time brake force minimization control (step S105 in Fig. 3) is executed. In the example that is in Fig. As shown in Figure 5, stationary steering is detected in advance before or after the vehicle has stopped, and the brake pressures of the steering wheels 51 and 52 are reduced to a level lower than the brake pressures during normal braking (shown by the dotted line in Figure 5). Fig. 5) After the vehicle has come to a stop, the brake pressures of the non-steering wheels 53 and 54 are simultaneously increased to a level greater than the brake pressures during normal braking. This reduces the steering load during steady-state steering and maintains the stopping braking force of the entire vehicle.

[0031] Fig. Figure 6 is a time graph illustrating an example of a change in vehicle speed and brake pressure when the pre-stop brake force minimization control (step S110 in Fig. 3) is executed. In the example that is in Fig. As shown in Figure 6, steady-state steering is detected in advance during vehicle braking when the vehicle speed falls below the predetermined speed. Immediately after detection, the brake pressures of the steering wheels 51 and 52 are reduced, and the steering load during steady-state steering is decreased. The control system allows the brake pressures of the steering wheels 51 and 52 to be reduced to zero before the vehicle comes to a stop, and steady-state steering can be performed immediately after the vehicle stops, in the state where the steering load is reduced.

[0032] Fig. Figure 7 is a time graph that shows another example of a change in vehicle speed and brake pressure when the pre-stop brake force minimization control (step S110 in Fig. 3) is executed. In the example that is in Fig. As shown in Figure 7, steady-state steering is detected in advance at the point during braking when the vehicle speed falls below the predetermined speed. Immediately after detection, the brake pressures of the steering wheels 51 and 52 are reduced, while simultaneously the brake pressures of the non-steering wheels 53 and 54 are increased. With this control system, steady-state steering can be performed immediately after the vehicle comes to a stop, even when the steering load is reduced, thus maintaining the overall stopping force of the vehicle. Here, the brake forces of the non-steering wheels 53 and 54 are increased such that the deceleration speed of the vehicle corresponds to that of normal braking, and the feel of the steering during braking is similar to that experienced during normal braking.

[0033] Fig. Figure 8 is a control block diagram that illustrates an example of a predefined precondition for detecting stationary steering in advance. In the present control block diagram, in addition to the configuration in Fig. 2. A mode switch 204 is included. A mode switch signal output by the mode switch 204 is, for example, a signal to the occupant indicating their intention to use brake force minimization control to reduce steering load during steady-state steering. It is a binary signal indicating a desired brake force minimization mode or a mode that does not. When the desired brake force minimization mode is selected, the pre-detection unit 203 determines that one of the predefined preconditions for detecting steady-state steering is met in advance. This desired brake force minimization mode is explained to users in advance as a mode that reduces steering load during steady-state steering, thus providing user comfort. Furthermore, the mode switch signal is, for example,A signal for the occupant indicating their intention to disable the brake force minimization control for reducing steering load during steady-state steering, and a binary signal indicating a mode to disable or not disable the brake force minimization control. When the mode to disable the brake force minimization control is selected, the pre-detection unit 203 determines that one of the predefined prohibition conditions for disabling the brake force minimization control is met.

[0034] Fig. 9 to Fig. Figure 12 are diagrams that illustrate examples of the given precondition for detecting stationary steering in advance.

[0035] In the example that is in Fig. As shown in Figure 9, the pre-detection unit 203 determines, when it detects that the vehicle's position has approached a parking position, that one of the preconditions for detecting stationary steering has been met in advance. Whether the vehicle's position has approached the parking position can be detected, for example, based on whether the distance between the vehicle's position and the parking position falls below a predefined distance using GPS or some other means of communication, or based on whether the vehicle's position has entered a predefined area (e.g., a parking area) that includes the parking position.

[0036] In the example that is in Fig. As shown in Figure 10, the pre-detection unit 203 determines that one of the preconditions for detecting stationary steering is fulfilled in advance when a gear change occurs during vehicle operation, resulting in a switch between forward and reverse movement. This is because a change of direction is often intended during a forward / reverse switch, and there is a high probability that stationary steering will occur immediately after the forward / reverse switch.

[0037] In the example that is in Fig. As shown in Figure 11, the pre-detection unit 203 determines that one of the preconditions for detecting steady-state steering is met in advance if the steering angles of the steering wheels 51 and 52 do not fall within a predetermined angular range that includes a neutral angle at the time the vehicle is stopped. This is because there is a high probability that steady-state steering will be performed just before the next forward or reverse movement when the vehicle is stopped with a steering angle, and there is a high probability that steady-state steering will be performed to return the steering angle to the neutral angle when the vehicle is stopped in the parked position.

[0038] In the example that is in Fig. As shown in Figure 12, the pre-detection unit 203 determines that one of the preconditions for detecting steady-state steering is fulfilled in advance when the vehicle performs a reverse movement. This is because there is a high probability that steady-state steering will be performed when stopping after a reverse movement.

[0039] Fig. 13 to Fig. Figure 17 are diagrams that illustrate examples of the specified prohibition condition for prohibiting the brake force minimization control.

[0040] In the example that is in Fig. As shown in Figure 13, the stopping brake force control unit 202 determines that one of the predefined prohibition conditions for disabling brake force minimization control is met when the steering angles of the steering wheels 51 and 52 fall within a predefined angular range that includes a neutral angle at the time the vehicle is stopped. This is because there is a high probability that when the steering angles of the steering wheels 51 and 52 are close to the neutral angle when the vehicle is stopped, this stop is a stop at the park position (or at least a high probability that this stop is not a stop for a change of direction).

[0041] In the example that is in Fig. As shown in Figure 14, the stopping brake force control unit 202 determines that, when the vehicle is decelerating and the vehicle's deceleration speed exceeds a predetermined deceleration speed, one of the predetermined prohibition conditions for disabling the brake force minimization control is met. This is done to prevent a lack of braking force or braking instability by minimizing the braking forces on the steered wheels during heavy braking.

[0042] In the example that is in Fig. As shown in Figure 15, the stopping brake force control unit 202 determines that one of the predefined prohibition conditions for disabling brake force minimization control is met when the vehicle is on a downhill slope. This is done to prevent a deficiency of braking forces for decelerating the vehicle and braking forces for maintaining the vehicle's stopped state by minimizing the braking forces of the steered wheels 51 and 52. Whether the vehicle is on a downhill slope is determined using an acceleration sensor, map information, or based on a change in driving resistance.

[0043] In the example that is in Fig. As shown in Figure 16, the stopping brake force control unit 202 determines, when the vehicle has slipped, that one of the specified prohibition conditions for prohibiting the brake force minimization control is met.

[0044] This is done to prevent a lack of braking force to avoid skidding by minimizing the braking forces of the steered wheels 51 and 52. It should be noted that whether the vehicle has skidded is determined based on wheel speed differences between wheels 51 to 54.

[0045] In the example that is in Fig. As shown in Figure 17, the stopping brake force control unit 202 determines that one of the predefined prohibition conditions for disabling the brake force minimization control is met in a situation where the braking forces of the steering wheels 51 and 52 are greater than a predefined braking force, or in a situation where the braking forces of the steering wheels 51 and 52 are not controlled by the occupant for the purpose of collision prevention by the vehicle's self-steering system. This is done to prevent insufficient braking forces that would hinder collision prevention by minimizing the braking forces of the steering wheels 51 and 52.

[0046] In the present embodiment, configured as described above, steering (steady steering) is detected in advance while the vehicle is stationary. The brake force minimization control, which reduces the braking forces of the steering wheels 51 and 52 to a level lower than the braking forces during normal braking, is executed before steady steering is initiated. This reduces the steering load during steady steering, decreases the stress on the steering system, and prevents stress buildup due to steady steering. Consequently, the stress on the tire, suspension, and steering system is reduced. Furthermore, by preventing stress buildup in the tire, suspension, and steering system, the anomalous noises and vehicle rocking that occur when minimizing the braking forces of the steering wheels 51 and 52 are prevented. Second embodiment

[0047] In the present embodiment, a case is assumed in which an autosteering system, not an occupant, operates a vehicle (which includes steering), and a case in which the occupant and the autosteering system jointly operate the vehicle. The autosteering system is a system that performs automatic operation, e.g., for the purpose of automatic parking, and is a system that performs automatic operation for the purpose of a U-turn. Such an autosteering system plans some route for the intended operation before the start of operation. A location where stationary steering is possible is planned in advance.Therefore, a brake force control device according to the present embodiment performs a brake force minimization control when stationary steering is detected in advance on the basis of an operating plan and it is determined that there is no problem if the braking forces of the steering wheels 51 and 52 are reduced.

[0048] Fig. 18 is a control block diagram representing a brake force control device 20A according to the present embodiment. A control block diagram (shown in Fig. 2 is shown) in the first embodiment different point in Fig. Paragraph 18 states that information from a steering planning unit 205 is input into a pre-detection unit 203. The steering planning unit 205 creates the operating plan based on input from various sensor devices and the occupant and, prior to executing steady-state steering, inputs information for steady-state steering into the pre-detection unit 203 based on the operating plan. When the information for steady-state steering is input, the pre-detection unit 203 determines whether steady-state steering is planned in a current stopped state or in the next stopped state. The steering planning unit 205, the pre-detection unit 203, and a stop-brake force control unit 202 can be mounted in a control unit for the autosteering system, can be mounted in the brake force control unit 20A, or can be mounted in a control unit other than those mentioned.

[0049] Fig. Figure 19 is a flowchart illustrating the brake force minimization control in the present embodiment. The control shown in the present flowchart is similar to the control in the first embodiment (which is described in Figure 19). Fig. (as shown in Figure 3) is executed on a continuous basis by the stopping brake force control unit 202. The following describes various aspects of the first embodiment.

[0050] In Fig. 19 In the present embodiment, the brake force minimization control has steps S102A and S107A instead of steps S102 and S107 of the first embodiment.

[0051] If step S101 determines that the vehicle is stopped, step S102A determines whether the pre-detection unit 203 has detected stationary steering in advance in the current stopped state. Here, the pre-detection unit 203 detects stationary steering in advance in the current stopped state if stationary steering in the current stopped state is planned in the operating schedule.

[0052] If step S102A determines that steady-state steering is not planned in the current stopped state (NO), normal control is executed (step S103) and processing returns to step S101. Conversely, if step S102A determines that steady-state steering is planned in the current stopped state (YES), it is determined (step S104) whether brake force minimization of the steering wheels 51 and 52 is permitted.

[0053] If in step S106 it is determined that the vehicle is in a braking process and a vehicle speed falls below a predetermined vehicle speed (YES), it is determined (step S107A) whether steady-state steering is planned in the operating plan for the next stopped state.

[0054] If step S107A determines that steady-state steering is not planned in the next stopped state (NO), normal control is executed (step S108) and processing returns to step S101. Conversely, if step S107A determines that steady-state steering is planned in the next stopped state (YES), step S109 determines whether brake force minimization of the steering wheels 51 and 52 is permitted just before coming to a complete stop.

[0055] In the present embodiment, configured as described above, similar effects to those in the first embodiment can be achieved. Furthermore, steady-state steering is detected in advance based on the operating plan, thus preventing the execution of unnecessary brake force minimization control when no steady-state steering is performed.

[0056] The embodiments of the present invention have been described in detail. However, the present invention is not limited to the embodiments described above and includes various modifications. For example, the embodiments have been described in detail for ease of understanding of the present invention, and the present invention is not necessarily limited to one embodiment that possesses all the described configurations. Furthermore, a part of the configuration of a particular embodiment can be added to the configuration of another embodiment, or a part of the configuration of a particular embodiment can be removed, or it can be replaced by a part of another embodiment. Reference symbol list 10 master cylinders 20, 20A ABS / ESC-ECU (Brake Force Control Unit) 30 Brake actuator 40 Steering assistance device 51, 52 steering wheel 53, 54 non-steering wheel 61 to 64 Wheel speed sensor 201 ABS / ESC control unit 202 Stop brake force control unit 203 Pre-detection unit 204 mode switch 205 Steering planning unit

Claims

[1] Vehicle brake force control device (20) comprising the following: a stopping brake force control unit (202) that individually controls the braking forces of a steered wheel (51, 52) and a non-steered wheel (53, 54) during deceleration of a vehicle; and a pre-detection unit (203) that detects steering in advance while the vehicle is stationary, wherein The stop-brake force control unit (202) then, when steering in a stopped state of the vehicle is detected in advance by the pre-detection unit (203), performs a brake force minimization control in order to reduce the braking force of the steering wheel (51, 52) such that it is less than the braking force during normal braking, wherein the stopping brake force control unit (202) does not execute the brake force minimization control when a vehicle condition meets a predefined predefined prohibition condition, and the specified prohibition condition includes a case in which the vehicle has skidded, whereby Based on a difference in wheel speed between the steering wheels and the non-steering wheels, it is determined whether the vehicle has skidded. [2] Vehicle brake force control device according to claim 1, wherein the stopping brake force control unit (202) increases the braking force of the non-steering wheel (53, 54) such that it is greater than the braking force during normal braking while simultaneously performing the brake force minimization control. [3] Vehicle brake force control device according to claim 1, wherein the pre-detection unit (203) detects steering in advance when the vehicle is stopped, during braking of the vehicle and then when the vehicle speed falls below a predetermined vehicle speed. [4] Vehicle brake force control device according to claim 2, wherein the stopping brake force control unit (202) increases the braking force of the non-steering wheel (53, 54) such that a deceleration speed of the vehicle corresponds to a deceleration speed during normal braking simultaneously with the execution of the brake force minimization control. [5] Vehicle brake force control device according to claim 1, wherein the pre-detection unit (203) detects steering in advance in the stopped state of the vehicle on the basis of whether a state of the vehicle meets a predetermined precondition. [6] Vehicle brake force control device according to claim 5, wherein the predetermined precondition includes a case in which a predetermined intention indication process has been carried out by an occupant. [7] Vehicle brake force control device according to claim 5, wherein the predetermined precondition includes a case in which the vehicle has entered a predetermined area which contains a parking position. [8] Vehicle brake force control device according to claim 5, wherein the specified precondition includes a case in which a forward / reverse changeover has been carried out by an occupant. [9] Vehicle brake force control device according to claim 5, wherein the predetermined precondition includes a case in which a steering angle of the steering wheel (51, 52) at a time when the vehicle is stopped does not fall within a predetermined angular range which includes a neutral angle. [10] Vehicle brake force control device according to claim 5, wherein the predetermined precondition includes a case in which the vehicle performs a reverse movement. [11] Vehicle brake force control device according to claim 1, wherein the specified prohibition condition includes a case in which a specified intention indication process has been carried out by an occupant. [12] Vehicle brake force control device according to claim 1, wherein the specified prohibition condition includes a case in which a steering angle of the steering wheel (51, 52) falls within a specified angular range at a time when the vehicle is stopped. [13] Vehicle brake force control device according to claim 1, wherein the specified prohibition condition includes a case in which a braking force of the vehicle is insufficient due to the design of the brake force minimization control. [14] Vehicle brake force control device according to claim 1, wherein the specified prohibition condition includes a case during braking of the vehicle in which a deceleration speed of the vehicle exceeds a specified deceleration speed. [15] Vehicle brake force control device according to claim 1, wherein the specified prohibition condition includes a case in which the vehicle is on a roadway with a gradient. [16] Vehicle brake force control device according to claim 1, wherein the specified prohibition condition includes a case in which the braking force of the steering wheel (51, 52) is greater than a specified braking force. [17] Vehicle brake force control device according to claim 1, wherein the specified prohibition condition includes a case in which the braking force of the steering wheel (51, 52) is controlled by a self-control system mounted on the vehicle for the purpose of preventing a collision of the vehicle. [18] Vehicle brake force control device according to claim 1, wherein the pre-detection unit (203) detects steering in advance while the vehicle is stopped, based on an operating plan created in a steering planning unit (205).

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