Automatic parking control device

Abstract

Automatic parking control device (60) applied to a vehicle (1) equipped with a drive device (20) and a brake device (30), and configured to perform automatic parking control that automatically moves the vehicle (1) into a target parking position (PT), wherein the drive device (20) comprises an internal combustion engine (22) and a torque converter (24) and is configured to output a vehicle driving force (Fd) transmitted to a wheel (2) of the vehicle (1), and wherein the brake device (30) is configured to generate a vehicle braking force (Fb) applied to the wheel (2). wherein the automatic parking control includes a drive force change cancellation control which controls the braking device (30) such that it generates the vehicle braking force (Fb) which cancels a change in the vehicle drive force (Fd) in connection with a change in an actual idle speed (NEi) of the internal combustion engine (22) when a target idle speed (NEit) changes in response to an idle speed change request, wherein the automatic parking control device (60) is configured such that it is in the drive force change cancellation control: executes a rotation prediction process to calculate a change section of a predicted idle speed corresponding to a change section of an idle speed (NEip) obtained by advancing a change section of the actual idle speed (NEia) in association with a change in the target idle speed (NEit) by a brake response delay time (tb) from a time at which a target vehicle braking force (Fbt) is directed to the brake device (30) to a time at which a change in the vehicle braking force (Fb) begins; executes a drive force prediction process to calculate a change section of a predicted drive force corresponding to a change section of the vehicle drive force (Fdp) according to the change section of the predicted idle speed; executes a brake force control process to calculate a change section of the vehicle brake force (Fb) as a change section of the target vehicle brake force (Fbt), which cancels out the change section of the predicted drive force, and to direct a calculated vehicle brake force change section to the brake device (30); and If the brake response delay time (tb) is longer than a machine response delay time (te) corresponding to a response delay time of the actual idle speed (NEia) with respect to the change in the target idle speed (NEit), a speed control delay process is performed to delay the change in the target idle speed (NEit) by a speed control delay time (tdlyc) starting from a time at which the idle speed change request is issued, wherein the speed control delay time (tdlyc) is greater than or equal to a difference (Δtbe) obtained by subtracting the machine response delay time (te) from the brake response delay time (tb).

Description

Background of the invention: Technical field

[0001] The present invention relates to an automatic parking control device which is configured to move a vehicle automatically. General state of the art

[0002] JP 2019 - 25 994 A discloses an automatic parking control device mounted on a vehicle equipped with: a drive device comprising an internal combustion engine and a torque converter, configured to output a vehicle propulsion force that is transmitted to the vehicle's wheels; and a braking device configured to generate a vehicle braking force applied to the wheels.

[0003] The automatic parking control device described above moves the vehicle automatically into a target parking position by performing a creep maneuver while the internal combustion engine is idling. However, to move the vehicle into the target parking position with high accuracy, it is necessary to travel at a lower speed than during the creep maneuver. To achieve this type of very low-speed driving, the automatic parking control device therefore combines the vehicle's braking force with the tractive force generated during idling. Summary of the invention

[0004] If the idle speed changes during the execution of the automatic parking control at very low speeds using creep mode, the vehicle's driving force also changes accordingly. There is concern that if this type of change in driving force cannot be adequately compensated for by adjusting the vehicle's braking force, a jolt due to acceleration or deceleration may occur in the vehicle, and the occupant may find the vehicle's behavior during the automatic parking control unpleasant.

[0005] JP 2019-25994A discloses a technology for actively adjusting the timing of brake force changes (increasing / decreasing) to alleviate occupant discomfort, even though the timing of the brake force change may differ from the timing of the drive force change due to changes in idle speed. In other words, JP 2019-25994A discloses measures that can alleviate occupant discomfort while avoiding the need to predict the timing of drive force and brake force changes.

[0006] However, to alleviate the occupant's discomfort, as described above, and to reduce the decrease in parking position accuracy, it is necessary to maintain a suitable change in the target vehicle braking force to correctly compensate for the change in the actual vehicle driving force resulting from a change in the actual idle speed due to a change in the target idle speed. For this purpose, it is advantageous to be able to accurately predict the change in idle speed, which forms the basis for calculating the change in the target vehicle braking force.

[0007] Furthermore, the automatic parking control should be achieved with the above-described prediction of the idle speed change section regardless of whether the brake device-side response delay time (i.e., the brake response delay time) or the response delay time of the actual idle speed change on the internal combustion engine side (i.e., the engine response delay time) is longer.

[0008] In order to alleviate the occupant's discomfort and reduce a decrease in parking position accuracy, it is also necessary to improve the prediction accuracy by means of a rotation prediction process to predict the idle speed change section described above.

[0009] The present invention was developed in consideration of the problem described above. The first object of the present invention is to achieve an automatic parking control system with a prediction of an idle speed change phase, regardless of whether the brake response delay or the engine response delay is longer. Furthermore, the second object is to improve the prediction accuracy in an automatic parking control system with a rotation prediction process for predicting an idle speed change phase, which forms the basis for calculating a change phase of a target vehicle braking force to counteract a change in a vehicle driving force.

[0010] An automatic parking control device according to a first aspect of the present invention is applied to a vehicle equipped with a drive device and a brake device, and is configured to perform automatic parking control, automatically moving the vehicle into a desired parking position. The drive device comprises an internal combustion engine and a torque converter and is configured to output a vehicle propulsion force transmitted to a wheel of the vehicle. The brake device is configured to generate a vehicle braking force applied to the wheel.The automatic parking control includes a drive force change cancellation control, which controls the braking device so that it generates the vehicle braking force, which cancels out a change in the vehicle drive force associated with a change in the actual idle speed of the internal combustion engine when a target idle speed changes in response to an idle speed change request.

[0011] The automatic parking control device is configured such that, in the drive force change cancellation control, it: performs a rotation prediction process to calculate a change section of a predicted idle speed corresponding to a change section of an idle speed obtained by advancing a change section of the actual idle speed associated with a change in the target idle speed by a brake response delay time from a time at which a target vehicle braking force is applied to the braking device to a time at which a change in the vehicle braking force begins; performs a drive force prediction process to calculate a change section of a predicted drive force corresponding to a change section of the vehicle drive force according to the change section of the predicted idle speed;executes a brake force control process to calculate a change section of the vehicle brake force as a change section of the target vehicle brake force, which cancels out the change section of the predicted drive force, and to instruct a calculated vehicle brake force change section to the brake device;and, if the brake response delay time is longer than a machine response delay time equal to a response delay time of the actual idle speed with respect to the change in the target idle speed, executes a speed control delay process to delay the change in the target idle speed by a speed control delay time starting from a time at which the idle speed change request is issued. The speed control delay time is longer than, or greater than or equal to, a difference obtained by subtracting the machine response delay time from the brake response delay time.

[0012] The rotation prediction process can include at least one process consisting of a prediction speed delay process, a rate limiting process, and a first-order delay process to calculate a waveform of the change section of the predicted idle speed based on a waveform of the target idle speed. The prediction speed delay process can delay a change start time of the waveform of the change section of the predicted idle speed such that it is delayed from a change start time of the target idle speed waveform by a prediction speed delay time corresponding to a difference obtained by subtracting the brake response delay time from the machine response delay time.The rate-limiting process can delay the slope of the predicted idle speed change waveform so that it is equal to or less than the maximum slope of the actual idle speed change that can be generated by the internal combustion engine. The first-order delay process can be applied to a predicted idle speed waveform without any process from the predicted speed delay and rate-limiting processes, or to a predicted idle speed change waveform after the predicted speed delay and / or rate-limiting processes.

[0013] An automatic parking control device according to a second aspect of the present invention is applied to a vehicle equipped with a drive device and a brake device, configured to perform automatic parking control that automatically moves the vehicle into a desired parking position. The drive device comprises an internal combustion engine and a torque converter and is configured to output a vehicle driving force transmitted to a wheel of the vehicle. The brake device is configured to generate a vehicle braking force applied to the wheel. The automatic parking control includes a drive force change cancellation control, which controls the brake device to generate the vehicle braking force that cancels out a change in the vehicle driving force associated with a change in the actual idle speed of the internal combustion engine.when a target idle speed changes in response to an idle speed change request. The automatic parking control device is configured such that, in the drive force change cancellation control, it: performs a rotation prediction process to calculate a change segment of a predicted idle speed that corresponds to a change segment of an idle speed obtained by advancing a change segment of the actual idle speed associated with a change in the target idle speed by a brake response delay time from the time at which a target vehicle braking force is applied to the braking device until the time at which a change in the vehicle braking force begins; performs a drive force prediction process,to calculate a change section of a predicted driving force corresponding to a change section of the vehicle driving force according to the change section of the predicted idle speed; executes a brake force control process to calculate a change section of the vehicle braking force that cancels the change section of the predicted driving force, and to instruct a calculated vehicle braking force change section to the braking device. The rotation prediction process comprises at least one process consisting of a prediction speed deceleration process, a rate limiting process, and a first-order deceleration process.to calculate a waveform of the change section of the predicted idle speed based on a waveform of the target idle speed. The predicted speed delay process delays a change start time of the waveform of the change section of the predicted idle speed so that it is delayed from a change start time of the waveform of the target idle speed by a predicted speed delay time, which corresponds to a difference obtained by subtracting the brake response delay time from a machine response delay time, which corresponds to a response delay time of the actual idle speed with respect to the change in the target idle speed. The rate limiting process delays a slope of the waveform of the change section of the predicted idle speed so that it is equal to or less than a maximum slope of the change in the actual idle speed.which can be generated by the internal combustion engine. The first-order delay process is applied to a waveform of the target idle speed without any process from the predictive speed delay process and the rate limiting process, or to a waveform of the change section of the predicted idle speed after the predictive speed delay process and / or the rate limiting process.

[0014] The rotation forecasting process can include all processes from the forecast rotation delay process, the rate constraint process, and the first-order delay process.

[0015] The rotation prediction process may include an interpolation process to calculate a change section of a final predicted idle speed by interpolating for each time step based on the change section of the predicted idle speed after at least one process from the prediction speed delay process, the rate limiting process and the first-order delay process, and the change section of the actual idle speed in relation to the change in the target idle speed.

[0016] The predicted RPM delay time may be longer if the internal combustion engine's coolant temperature is lower.

[0017] The slope of the waveform of the change section of the predicted idle speed after a restriction by the rate limiting process may be smaller if the internal combustion engine's coolant temperature is lower.

[0018] If, according to the first aspect of the present invention, the brake response delay time is longer than the engine response delay time, the speed control delay process is carried out. In this process, the change in the target idle speed is delayed by the speed control delay time, which is greater than or equal to the difference obtained by subtracting the engine response delay time from the brake response delay time, starting from the time the idle speed change request is issued. As a result, it becomes possible to perform automatic parking control (drive force change cancellation control) with the prediction (calculation) of the change portion of the predicted idle speed, even if the brake response delay time is longer than the engine response delay time.Thus, according to the first aspect, the automatic parking control device enables the achievement of automatic parking control with the prediction of the idle speed change section (calculation of the predicted idle speed) regardless of whether the brake response delay time or the machine response delay time is longer.

[0019] According to the automatic parking control device of the second aspect of the present invention, the calculation of the change in the predicted idle speed is performed by the rotational prediction process, which comprises at least one process from the predicted speed deceleration process, the rate limitation process, and the first-order deceleration process. Consequently, it becomes possible to suitably increase the accuracy of the calculation (prediction) of the change in the predicted idle speed, which forms the basis for calculating the change in the target vehicle braking force to counteract the change in the vehicle driving force. Brief description of the illustrations Fig. Figure 1 is a block diagram showing a configuration example of an automatic parking system according to an embodiment of the present invention; Fig. Figure 2 is a schematic diagram showing an example of a configuration around a vehicle's drive unit, as described in Fig. The automatic parking system shown in section 1 is equipped with it; Fig. Figure 3 is a conceptual illustration used to describe a basic part of an automatic parking control system according to the embodiment of the present invention; Fig. Figure 4 is a time diagram used to describe the basic features of a drive force change cancellation control; Fig. Figure 5 is a timing diagram used to describe a second problem (a problem relating to achieving drive force change cancellation control regardless of whether a brake response delay time tb or a machine response delay time te is longer); Fig. Figures 6A-6C are timing diagrams used to describe each process consisting of a forecast speed delay process, a rate limiting process, and a first-order delay process, which are included in a rotation forecast process according to the embodiment of the present invention; Fig. Figure 7 is a diagram showing a relationship between the machine response delay time te and a machine cooling water temperature; Fig. Figure 8 is a diagram showing a relationship between the slope S of a predicted waveform Wp2 after the rate limiting process and the machine cooling water temperature; Fig. Figure 9 is a time diagram used to describe an example of the rotation prediction process carried out in the embodiment of the present invention; Fig. Figure 10 is a timing diagram used to describe the basic features of a speed control delay process; and Fig. Figure 11 is a flowchart showing a processing routine relating to the automatic parking control in conjunction with the drive force change cancellation control according to the embodiment of the present invention. Detailed description

[0020] Even if the number, quantity, amount, range, or other numerical property of an element is mentioned in the following embodiments, it is understood that the present invention is not limited to the mentioned numerical property unless explicitly described otherwise or the present invention is theoretically explicitly specified by the numerical property. Furthermore, structures, steps, or the like described in connection with the following embodiments are not necessarily essential to the present invention unless explicitly stated otherwise or the present invention is theoretically explicitly specified by the structures, steps, or the like.

[0021] Embodiments according to the present invention are described with reference to the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10 to Fig. 11 described. 1. Configuration example of an automatic parking system

[0022] Fig. Figure 1 is a block diagram showing a configuration example for an automatic parking system 10 according to one embodiment. Fig. Figure 2 is a schematic diagram showing an example of a configuration around a drive device 20 of a vehicle 1, which is equipped with the in Fig. The automatic parking system shown in section 1 is equipped with 10.

[0023] The automatic parking system 10 is mounted on the vehicle 1 and is equipped with the drive device 20, a brake device 30, sensors 40, an HMI unit (human-machine interface) 50, and a control device 60. The control device 60 is configured to perform an “automatic parking control” for automatically moving the vehicle 1 to or into a target parking position, which corresponds to an example of the “automatic parking control device” according to the present invention.

[0024] The drive system 20 comprises an internal combustion engine 22, configured to generate a machine torque Te, and a torque converter (TC) 24, arranged between the internal combustion engine 22 and the wheels (drive wheels) 2 of the vehicle 1. The drive system 20 may also include, for example, a stepped or continuously variable automatic transmission 26 and a differential 28. The drive system 20 is also referred to as the drivetrain and outputs a vehicle driving force (vehicle driving torque) Fd, which is transmitted to the wheel 2. More precisely, the machine torque Te generated by the internal combustion engine 22 is transmitted to the wheels 2 via the torque converter 24, the automatic transmission 26, and the differential 28.

[0025] When the internal combustion engine 22 is idling, it generates an idle torque depending on the idle speed NEi. The internal combustion engine 22 includes, in particular, a throttle or throttle valve 22a, a fuel injection device (only fuel injectors 22b are shown), and an ignition device (only spark plugs 22c are shown) as actuators for controlling the engine torque Te. The generated idle torque is transmitted via the torque converter 24 as creep torque (creep force) to the automatic transmission 26. The drive device 20 transmits the vehicle tractive force Fd to the wheels 2 depending on this creep force and the respective gear ratios of the automatic transmission 26 and the differential 28.In neutral, vehicle 1 can perform a creeping motion using this vehicle tractive force Fd (hereinafter also simply referred to as "tractive force Fd"). If the idle speed NEi changes, the tractive force Fd also changes accordingly.

[0026] The braking device 30 generates a vehicle braking force (vehicle braking torque) Fb, which is applied to the wheels 2. This braking device 30 comprises a master brake cylinder, a brake actuator, and wheel cylinders, which are not shown. The wheel cylinders are located at the respective wheels 2. The brake actuator supplies brake fluid from the master brake cylinder to each wheel cylinder to generate a brake pressure (i.e., the braking force Fb). According to the braking device 30 with this type of configuration, the braking force Fb can be controlled based on a command from the control device 60.

[0027] The sensors 40 are designed to acquire information required for automatic parking control. Specifically, the sensors 40 comprise one or more external sensors for detecting the situation around vehicle 1. These external sensors include, for example, one or more cameras configured to image the vehicle's surroundings. Based on the image information captured by the camera(s), the automatic parking control can detect a target parking position PT for vehicle 1 and calculate the remaining distance X to the target parking position PT. Additionally, the external sensors may include an ultrasonic sonar (distance sonar) configured to detect obstacles around vehicle 1.Using the ultrasonic sonar, the remaining distance X to the target parking position PT can be calculated. In addition, the sensors 40 can include a wheel speed sensor configured to detect wheel rotation. Based on the wheel speed sensor reading, the vehicle's travel distance 1 can be calculated. Furthermore, the sensors 40 include: a crank angle sensor configured to detect the rotational speed (engine speed) NE of a crankshaft 22d of the internal combustion engine 22; a turbine speed sensor configured to detect the rotational speed (turbine speed) NT of an output shaft 24a of the torque converter 24; and an engine coolant temperature sensor configured to detect the engine coolant temperature. The sensors 40 output the acquired information to the control device 60.

[0028] The HMI unit 50 corresponds to an interface for providing various information to the user of the vehicle 1 and for receiving information from the user. The HMI unit 50 includes, for example, an input device, a display device, and a speaker. Examples of the input device include a touch panel, a keypad, a switch, and a button. The input device includes, in particular, an "automatic parking switch" for turning the automatic parking function on and off. The user can use the input device to enter information into the HMI unit 50. The HMI unit 50 sends the information entered by the user to the control device 60.

[0029] The control device 60 is configured to perform automatic parking control. The control device 60 is configured by an electronic control unit (ECU) and corresponds to a microcomputer comprising processors 60a and memory 60b. The control device 60 receives information from sensors 40 and the HMI unit 50 and performs automatic parking control based on the received information.

[0030] The function of the control device 60 is realized by the processors 60a executing control programs stored in the memory 60b. The control programs can be stored on a computer-readable recording medium. It should be noted that the control device 60 can be configured by a plurality of ECUs, such as an automatic parking ECU, which is configured to primarily perform automatic parking control, a machine ECU, which is configured to control the operation of the internal combustion engine 22, and a brake ECU, which is configured to control the brake device 30. 2. Automatic parking control

[0031] As described above, the control device 60 performs the “automatic parking control” to automatically move the vehicle 1 into the target parking position PT. It should be noted that the automatic parking control comprises at least a steering control consisting of the steering control and a gear shift control, together with the “vehicle speed control (that is, drive force control and brake force control)”. As described below, in the present embodiment, particular attention is paid to the “vehicle speed control”. The steering control and the gear shift control are not specifically limited. 2-1. Basic part of the automatic parking control

[0032] Fig. Figure 3 is a conceptual illustration used to describe a fundamental part of the automatic parking control system according to the embodiment. As previously described, the vehicle 1 can perform a creep speed, and the control device 60 uses this creep speed to automatically move the vehicle 1 into the target parking position PT. However, to move the vehicle 1 into the target parking position PT with high accuracy, it is necessary to drive the vehicle 1 at a lower speed than the creep speed. Therefore, according to the vehicle speed control of the automatic parking control system, the control device 60 controls the movement of the vehicle 1 by controlling the braking force Fb while the internal combustion engine 22 is idling. That is, by combining the braking force Fb with the driving force Fd according to the idle speed NEi, a very slow vehicle movement is achieved.

[0033] In particular, the control device 60 first performs a "target position setting process" to set the target parking position PT in the automatic parking control system. This target position setting process is carried out on the basis of the acquisition information received from the sensors 40.

[0034] Furthermore, during vehicle speed control, the control device 60 regulates the driving force Fd by controlling the operation of the internal combustion engine 22. More precisely, the control device 60 stores a target idle speed NEit. When the control device 60 operates in idle mode, as during automatic parking control, it performs "idle speed control" to bring the actual idle speed NEia closer to the target idle speed NEit. During automatic parking control, the drive device 20 generates a driving force Fd in relation to the actual idle speed NEia, which is controlled by the idle speed control.

[0035] The calculation of the driving force Fd in relation to the actual idle speed NEia can be carried out, for example, using a relationship of the following equation 1. Driving force Fd=NE2×C(e)×TR(e)×GR

[0036] The actual no-load speed NEia is substituted for NE in equation 1. C(e) and TR(e) in equation 1 are a volume coefficient and a torque ratio, respectively, which represent the properties of the torque converter 24 and assume values ​​corresponding to a speed ratio e (= speed NT of the output shaft 24a / machine speed NE). The product NE 2*C(e) in Equation 1 corresponds to the input torque of the torque converter 24 (that is, the machine torque Te). The torque ratio TR(e) corresponds to the ratio of the output torque of the torque converter 24 to its input torque (machine torque Te). GR in Equation 1 represents a transmission ratio that encompasses the transmission ratios of the automatic transmission 26 and the differential 28. Therefore, according to Equation 1, the drive torque (drive force Fd) is calculated, which is output by the drive device 20 and applied to the wheels 2.

[0037] Regarding the calculation of the driving force Fd, the volume coefficient C(e) and the torque ratio TR(e) can be calculated according to the speed ratio e, for example, from a characteristic map (not shown) that defines a relationship between both the volume coefficient C(e) and the torque ratio TR(e) and the speed ratio e. The machine speed NE (actual idle speed NEia) and the speed NT of the output shaft 24a for calculating the speed ratio e can be calculated, for example, using the crankshaft angle sensor and the turbine speed sensor, respectively. However, the speed NT is very low during very low-speed driving, during which the automatic parking control is performed. For this reason, the volume coefficient C(e) and the torque ratio TR(e) can be calculated according to the speed ratio e, while the speed ratio e is simply considered to be zero.

[0038] Furthermore, the control device 60 calculates the remaining distance X (see Fig. 3) from the current position of vehicle 1 to the target parking position PT based on the detection information received by the sensors 40. For example, the target parking position PT can be determined by performing an image analysis of the image information captured by the camera and calculating the remaining distance X to the target parking position PT. Alternatively, the remaining distance X can be calculated from the distance to the obstacle detected by the ultrasonic sonar (distance sonar). Alternatively, based on the detection result of the wheel speed sensor, the movement distance of vehicle 1 can be calculated and then the remaining distance X to the target parking position PT can be calculated.

[0039] More precisely, the control device 60 performs the vehicle speed control described above based on the remaining distance X and the current driving force Fd. The target vehicle speed in automatic parking control is expressed as a function of the remaining distance X. If the remaining distance X is zero, the target vehicle speed is also zero. Furthermore, this target vehicle speed corresponds to a very low speed, lower than the creep speed. This type of very low speed is achieved by combining the braking force Fb with the driving force Fd (creep torque) in conjunction with the actual idle speed NEia.Therefore, the control device 60 calculates a target braking force (target vehicle braking force) Fbt, based on the current driving force Fd and the remaining distance X, which is required to reach the target vehicle speed. The control device 60 also controls the operation of the braking device 30 so that the calculated target braking force Fbt is achieved. The vehicle 1 approaches the target parking position PT at a speed determined by the combination of the driving force Fd and the braking force Fb. 2-2. Drive force change cancellation control

[0040] During the execution of the automatic parking control (vehicle speed control) at a very low speed using creep mode, the idle speed NEi can change. One factor contributing to this change in idle speed NEi is, for example, a change in the load of an auxiliary device of the internal combustion engine 22 (such as an air conditioning compressor or alternator). Typically, when the air conditioning is operating (i.e., air conditioning ON), an "idle speed increase request" is made to raise the idle speed NEi. The control device 60 increases the target idle speed NEit in response to this idle speed increase request. Furthermore, with the idle speed control described above, the control device 60 controls the throttle valve 22a to increase the throttle opening and controls each fuel injector 22b to increase the amount of fuel injected.Consequently, the actual idle speed NEia increases. Conversely, when the air conditioning is stopped (i.e., air conditioning OFF), an "idle speed reduction request" is made to decrease the idle speed NEi. The control device 60 lowers the target idle speed NEit in response to the idle speed reduction request. Furthermore, the control device 60, through idle speed control, controls the throttle valve 22a to decrease the throttle opening and controls each fuel injector 22b to reduce the fuel injection quantity. Consequently, the actual idle speed NEia decreases. Thus, the actual idle speed NEia is increased or decreased by the idle speed control described above to match the target idle speed NEit, which changes in response to the idle speed increase / decrease request.

[0041] If the actual idle speed NEia changes as described above during the execution of the automatic parking control using creep mode, the driving force Fd also changes accordingly. There is a concern that if the driving force Fd, which changes in this way, cannot be properly compensated for by adjusting the braking force Fb, a jolt due to acceleration or deceleration may occur in vehicle 1, and the occupant may experience discomfort with the behavior of vehicle 1 during the automatic parking control. Furthermore, there is a concern that the accuracy of the parking position may decrease due to the automatic parking control. 2-2-1. Basic principles of the drive force change cancellation control (basic part)

[0042] The automatic parking control according to the present embodiment comprises the following "drive force change cancellation control". That is, according to this drive force change cancellation control, if the target idle speed NEit changes in response to the idle speed up / down request (idle speed change request), the braking device 30 is controlled to generate a braking force Fb which cancels the change in drive force Fd due to the change in the actual idle speed NEia.

[0043] Fig. Figure 4 is a timing diagram used to describe the basic principles of the drive force change cancellation control. Fig. Figure 4 shows an example of each operation of the machine speed NE, the driving force Fd, and the braking force Fb at the time of the idle-up request. It should be noted that the operation at the time of the idle-down request is the same, except that the positive and negative directions of the changes in the respective waveforms of the machine speed NE, the driving force Fd, and the braking force Fb are opposite to those shown in Figure 4. Fig. The four items shown are already described, and therefore their descriptions are omitted. This also applies to those described below. Fig. 5, 6A-6C, 9 and 10.

[0044] There is a response delay when changing the actual idle speed NEia relative to the change in the target idle speed NEit. If in the Fig. In the example shown in Figure 4, when the target idle speed NEit begins to increase at time t1, the actual idle speed NEia begins to increase at time t3, which is delayed by a machine response delay time te from time t1. The response delay of the actual value to a target value change is present not only on the side of the internal combustion engine 22 (side of the drive device 20), but also on the side of the brake device 30. A Fig. The brake response delay time tb shown in Figure 4 corresponds to the time from a point in time at which the target braking force Fbt is instructed to the braking device 30 until a point in time at which the braking force Fb (actual braking force Fba) begins to change.

[0045] In the drive force change cancellation control, the control device 60 performs a "rotation prediction process" to determine the start time (in Fig. 4, time t3) of the change in the driving force Fd (actual driving force Fda) in connection with the change in the target idle speed NEit and the start time of the change in the braking force Fb (actual braking force Fba) to cancel the change in the driving force Fd taking into account the presence of the machine response delay time te and the brake response delay time tb.

[0046] The rotation prediction process corresponds to a process for calculating (predicting) a "change segment of a predicted idle speed NEip". The change segment of the predicted idle speed NEip (see, for example, a single-point dashed line in Fig. 4) corresponds to an idle speed change section obtained by advancing or shifting the change section of the actual idle speed NEia in conjunction with a change in the target idle speed NEiT by the brake response delay time tb. In the Fig. In example 4, a time t2, which has advanced by the brake response delay time tb with reference to the change start time t3 of the actual idle speed NEia, corresponds to the change start time of the target idle speed NEip.

[0047] In the drive force change cancellation control, the control device 60 also performs a "drive force prediction process" and a "brake force control process".

[0048] The driving force prediction process corresponds to a process for calculating a change section of a predicted driving force Fdp (see, for example, the single-point dashed line in Fig. 4), which corresponds to the change in the driving force Fd according to the change in the predicted idle speed NEip, calculated by the rotation prediction process. That is, the driving force prediction process corresponds to a process for converting the change in the predicted idle speed NEip, calculated by the rotation prediction process, into the change in the driving force Fd. This conversion can be carried out, for example, by substituting the predicted idle speed NEip into NE in Equation 1 described above.

[0049] The brake force control process corresponds to a process to determine, as a change section, the target braking force Fbt (see e.g. dashed line in Fig. 4) to calculate a change in the braking force Fb to cancel out the calculated change in the predicted driving force Fdp and then to instruct or specify the calculated change in the target braking force Fbt to the braking device 30. This change in the target braking force Fbt (that is, the reaction force which cancels out the change in the predicted driving force Fdp) is obtained by reversing the sign of the change in the predicted driving force Fdp, as in Fig. 4 shown.

[0050] According to the drive force change cancellation control, the change section of the target braking force Fbt, which is calculated as described above, is communicated to the brake device 30 at time t2, which is delayed by the brake response delay time tb with respect to the change start time of the actual drive force Fda (in Fig. 4 has advanced to time t3). Consequently, the actual braking force Fba, which cancels out this change, can be applied to wheels 2 at the time that coincides with the start of the change in the actual driving force Fda.

[0051] Furthermore, in the rotation prediction process performed in the drive force change cancellation control, as in the specific example described in detail below, the change section of the predicted idle speed NEip is calculated, while the shape of the waveform of the change section of the actual idle speed NEia due to the change in the target idle speed NEiT is reproduced as accurately (faithfully) as possible. This serves to obtain the waveform of the change section of the target braking force Fbt, which is calculated based on the change section of the predicted idle speed NEip, as a waveform obtained by inverting the waveform of the change section of the actual drive force Fda in relation to the change section of the actual idle speed NEia as accurately as possible. If this type of waveform of the change section of the target braking force Fbt can be obtained, as in Fig. As shown in Figure 4, the change in the actual braking force Fba, which can precisely cancel out the change in the actual driving force Fda, can then be applied to the wheels 2. This leads to a reduction in the occupant's discomfort with the vehicle's behavior and to a decrease in the decrease in parking position accuracy, which is attributable to the inability to adequately cancel out the change in the actual driving force Fda due to the change in the actual idle speed NEia. 2-2-2. Problems with the drive force change cancellation control

[0052] To alleviate the occupant's discomfort and reduce the decrease in parking position accuracy due to the implementation of the drive force change cancellation control, it is necessary to increase the prediction accuracy through the rotation prediction process for forecasting the change in idle speed (i.e., the change in the predicted idle speed NEip), which forms the basis for calculating the change in the target braking force Fbt (first problem). It should be noted that this "first problem" corresponds to the "first objective" according to the present invention.

[0053] Furthermore, the automatic parking control is to be achieved by predicting the change section of the predicted idle speed NEip (more precisely, the drive force change cancellation control) regardless of whether the brake response delay time tb or the response delay time (machine response delay time te) of the change in the actual idle speed NEia is longer (second problem). It should be noted that this “second problem” corresponds to the “second objective” according to the present invention.

[0054] Fig. Figure 5 is a timing diagram used to describe the second problem (a problem relating to achieving the drive force change cancellation control regardless of whether the brake response delay time tb or the machine response delay time te is longer). If the machine response delay time te is longer than the brake response delay time tb, as in the diagram in Fig. In the example shown in Figure 4 above, or if the machine response delay time te is equal to the brake response delay time tb, it is possible to predict the change in the predicted idle speed NEip that has advanced by the brake response delay time tb relative to the change start time of the actual idle speed NEia. By then applying the change in the actual braking force Fba to the wheels 2 based on this change in the predicted idle speed NEip, the change in the actual driving force Fda can be canceled out.

[0055] On the other hand, it shows Fig. 5. An example where the brake response delay time tb is longer than the machine response delay time te. If the idle speed NEi, with respect to a change start time t3' of the actual idle speed NEia, in this example begins to rise earlier by the brake response delay time tb, as in Fig. As shown in Figure 5, the change start time t2' of the change section of the idle speed NEip to be predicted is earlier than the change start time t1 of the target idle speed NEit. Therefore, the prediction cannot be performed. That is, the longest brake response delay time tb with which the prediction can be performed is obtained when the brake response delay time tb equals the machine response delay time te.

[0056] The inability to calculate the predicted idle speed NEip, as described above, means that it becomes impossible to calculate the change in the target braking force Fbt to cancel out the change in the actual driving force Fda at the time (in Fig. 5, time t2'), which has advanced by the brake response delay time tb with respect to the change start time t3' of the actual idle speed NEia, to instruct or communicate. Furthermore, in the example where the brake response delay time tb is longer than the machine response delay time te, the earliest time at which the instruction for the change section of the target braking force Fbt can be started corresponds to time t1, as in Fig. 5 shown. However, if the instruction is given at time t1, the start of the application of the change section of the actual braking force Fba is delayed by the difference (= tb-te) between the brake response delay time tb and the machine response delay time te, with reference to the start of the occurrence of the change section of the actual driving force Fda (that is, with reference to time t3'). 2-2-3. Specific example of the rotation forecasting process

[0057] As previously described, the rotation prediction process is a process for calculating (predicting) the change segment of the predicted idle speed NEip, which is obtained by advancing the change segment of the actual idle speed NEia due to the change in the target idle speed NEit by the brake response delay time tb. With regard to the first problem described above, the "rotation prediction process" is implemented according to the present embodiment as follows.

[0058] The Fig. Figures 6A-6C are timing diagrams used to describe each process consisting of a forecast speed delay process, a rate limiting process, and a first-order delay process, which are included in the rotation forecast process according to the embodiment. Each of the Fig. Figures 6A-6C show an optimal waveform Wopt for the change segment of the predicted idle speed NEip. This optimal waveform Wopt corresponds to the waveform obtained by paralleling or shifting the waveform of the change segment of the actual idle speed NEia, such that it advances by the brake response delay time tb, without altering the shape of the waveform. That is, the optimal waveform Wopt is the best prediction result of the waveform (hereinafter also referred to simply as the "predicted waveform Wp") of the change segment of the predicted idle speed NEip by the rotational prediction process.Therefore, the higher the degree of agreement between the predicted waveform Wp and the optimal waveform Wopt, the more suitable the change section of the actual driving force Fda can be canceled by using the actual braking force Fba based on the calculated change section of the predicted idle speed NEip.

[0059] In order to obtain the predicted waveform Wp as close as possible to the optimal waveform Wopt, the rotation prediction process accordingly includes the "prediction speed delay process", the "rate limiting process" and the "first order delay process" to calculate the predicted waveform Wp based on the waveform of the target idle speed NEiT.

[0060] The forecast speed delay process, the rate constraint process, and the first-order delay process are described in that order with reference to the Fig. 6A-6C are described individually. Each of these figures represents the waveform of the change section of the target idle speed NEit, which is incrementally increased in response to an idle-up request, as shown by the dashed line. (Forecast-speed-delay process)

[0061] First, it Fig. 6A represents a waveform (predicted waveform Wp1) of the change section of a predicted idle speed NEip1, obtained by performing the predicted speed delay process for the waveform of the target idle speed NEit. This predicted speed delay process corresponds to a process for delaying the change start time of the predicted waveform Wp1, such that a time t4 is obtained that is delayed by a predicted speed delay time tdlyp from the change start time t1 of the waveform of the target idle speed NEit. The predicted speed delay time tdlyp corresponds to the “difference obtained by subtracting the brake response delay time tb from the machine response delay time te”, as described in Fig. 6A is shown. It should be noted that, as described below Fig. Figure 10 shows that the predicted speed delay time tdlyp, when the speed control delay process is carried out, corresponds to a difference obtained by subtracting the brake response delay time tb from a ‘machine response delay time te’ after the speed control delay process.

[0062] Furthermore, the predictive speed delay process is performed to delay the change start time of the predicted waveform Wp1 until the change start time t4 of the optimal waveform Wopt of the change section of the predicted idle speed NEip. The machine response delay time te and the brake response delay time tb, which are used to calculate the predictive speed delay time tdlyp, can be obtained in advance, for example, by conducting experiments. Both delay times te and tb can be fixed values; however, here, the delay times te and tb are calculated as an example. Fig. Figure 7 is a diagram showing the relationship between the machine response delay time te and the machine cooling water temperature. That is, the machine response delay time te changes, for example, depending on the machine cooling water temperature. In particular, as shown in Fig. As shown in Figure 7, the machine response delay time is longer when the machine cooling water temperature is lower. Therefore, the control device 60 stores the value in Fig. The relationship shown in Figure 7 is stored as a characteristic map in memory 60b, and the machine response delay time te is calculated as a function of the machine cooling water temperature from this type of characteristic map. Then, for example, the difference between the machine response delay time te calculated in this way and the brake response delay time tb, which corresponds to a fixed value, can be calculated as the predicted speed delay time tdlyp. Furthermore, the brake response delay time tb changes, for example, depending on the brake oil pressure and brake oil temperature. Therefore, the brake response delay time tb, which is used to calculate the predicted speed delay time tdlyp, can be changed according to the brake oil pressure and / or the brake oil temperature.Alternatively, the forecast speed delay time tdlyp can be calculated, for example, to be longer when the machine cooling water temperature is lower, from a characteristic map that defines the relationship between the forecast speed delay time tdlyp itself and the machine cooling water temperature. (Rate restriction process)

[0063] Next, [the text] presents Fig. Figure 6B represents a waveform (predicted waveform Wp2) of the change section of a predicted idle speed NEip2, obtained by performing the rate-limiting process for the waveform of the target idle speed NEit. This rate-limiting process corresponds to a process for limiting a slope S of the predicted waveform Wp2 such that it is equal to or less than the maximum slope of the change in the actual idle speed NEia that the internal combustion engine 22 can produce. As an example, the slope S of the waveform Wp2 is shown in the figure below. Fig. 6B shows the predicted waveform Wp2 restricted so that it matches the maximum slope described above, which is obtained, for example, by conducting experiments in advance.

[0064] Furthermore, the slope S of the predicted waveform Wp2 can be a fixed value after the rate constraint process; however, here the slope S is calculated as follows. Fig. Figure 8 is a diagram showing the relationship between the slope S of the predicted waveform Wp2 after the rate-limiting process and the machine cooling water temperature. The maximum slope described above changes, for example, depending on the machine cooling water temperature. In particular, the maximum slope becomes smaller (more gradual) as the machine cooling water temperature decreases. For this reason, as shown in Fig. As shown in Figure 8, the rate-limiting process restricts the slope S such that the slope S of the predicted waveform Wp2 becomes smaller when the machine cooling water temperature is lower. In detail, the control device 60 stores the information in Fig. The relationship shown in memory 60b is considered a characteristic map and calculates the slope S of the predicted waveform Wp2 as a function of the machine cooling water temperature from this type of characteristic map. (First-order delay process)

[0065] Next, [the text] presents Fig. 6C represents a waveform (predicted waveform Wp3) of the change section of a predicted idle speed NEip3, which is obtained by performing the first-order delay process for the waveform of the target idle speed NEit. In the Fig. In the example shown in 6C, the first-order delay process is applied to the waveform (dashed line) of the target idle speed NEit, which is not accompanied by either the predictive speed delay process or the rate limiting process.

[0066] The first-order delay process can be performed, for example, using the following Equation 2. Specifically, the predicted idle speed NEip3 after the first-order delay process at the current sampling time k (that is, the current value of the predicted idle speed NEip3) is denoted as NEip3(k). This current value NEip3(k) is obtained by adding the last value NEip3(k-1) of the predicted idle speed NEip3 to a value obtained by multiplying the difference between the current value NEit(k) of the predicted idle speed NEit before the first-order delay process and the last value NEip3(k-1) of the predicted idle speed NEip3 by a specific time constant τ.It should be noted that this time constant τ is determined in advance, for example by conducting an experiment, as a value that reflects the response delay characteristics of the actual idle speed NEia. NEip3(k)=(NEit(k)−NEip3(k−1))×τ+NEip3(k−1)

[0067] Additionally, in contrast to the one in Fig. The example shown in Figure 6C illustrates how the “first-order delay process” according to the present invention is applied to a waveform of the forecast idle speed change section after both the forecast speed delay process and the rate limiting process have been applied, as in a Fig. 9 shown in the example described below, or this can be applied to a waveform of the forecast idle speed change section after either the forecast speed delay process or the rate limiting process has been applied. (Example of the rotation prediction process)

[0068] Fig. Figure 9 is a time diagram used to describe an example of the rotation prediction process implemented in the embodiment. The rotation prediction process according to the present embodiment is executed by a combination of all processes from the prediction speed delay process, the rate limiting process, and the first-order delay process described above. Furthermore, the rotation prediction process according to the present embodiment is executed with the following interpolation process.

[0069] In particular, according to the rotation prediction process of the present embodiment, the predicted waveform Wp1 is first calculated, which is obtained by applying the prediction speed delay process to the waveform Wt of the target idle speed NEit, as shown in Fig. Figure 9 shows that a predicted waveform Wp2' is then calculated, which is obtained by applying the rate-limiting process to the predicted waveform Wp1. A predicted waveform Wp3' ​​is also calculated, which is obtained by applying the first-order retardation process to the predicted waveform Wp2'. This calculation of the predicted waveform Wp3' ​​can be performed in the same way by replacing the current value NEit(k) of the target idle speed NEit before the first-order retardation process in Equation 2 with the current value NEip2'(k) of the predicted idle speed NEip2' in the predicted waveform Wp2' after the rate-limiting process. (Interpolation process)

[0070] Furthermore, in the rotation prediction process according to the present embodiment, the "interpolation process" is applied to the change section of the predicted idle speed NEip3' after the first-order delay process, which is calculated as described above. The prediction speed delay process, the rate limiting process, and the first-order delay process, as described above, are performed based on the target idle speed NEit at time t1, when the waveform of the target idle speed NEit is obtained. In contrast, the interpolation process is a process for calculating a final predicted idle speed NEipf by performing an interpolation for each time step (control period) based on the change section of the predicted idle speed NEip3' and the change section of the actual idle speed NEia.

[0071] In particular, according to the interpolation process, for example, the following equation 3 is used to calculate the current value NEipf (k) of the final predicted idle speed NEipf by performing an interpolation based on the current value NEip3' (k) of the predicted idle speed NEip3' after the first-order delay process and the current value NEia (k) of the actual idle speed NEia. This type of calculation of the interpolation process is then performed repeatedly for each time step over a time span from a change start time t5 of the predicted idle speed NEip3' to a change end time t6 of the actual idle speed NEia. NEipf(k)=(NEia(k)−NEip3'(k))×K+NEip3'(k)

[0072] The interpolation coefficient K in equation 3 is adjusted so that the predicted waveform Wpf, which corresponds to the waveform of the change section of the final predicted idle speed NEipf, can be as close as possible to the optimal waveform Wopt, for example by conducting experiments in advance.

[0073] Fig. Figure 9 also represents the final predicted waveform Wpf after the interpolation process described above. Fig. Figure 9 shows that the obtained predicted waveforms Wp1, Wp2', and Wp3' ​​can be gradually approximated to the optimal waveform Wopt by sequentially performing the predicted speed delay process, the rate limiting process, and the first-order delay process. Furthermore, it is evident that by continuing the interpolation process described above, a predicted waveform Wpf can be obtained that is even closer to the optimal waveform Wopt.

[0074] Additionally, it Fig. Figure 9 represents a waveform of the actual idle speed NEia, which changes with an overshoot relative to the change in the target idle speed NEit. According to the interpolation process described above, the overshoot section can also be represented as in the Fig. The predicted waveform Wpf shown in 9 can be expressed. 2-2-4. Speed ​​control delay process

[0075] In view of the second problem described above, the control device 60, according to the drive force change cancellation control of the present embodiment, performs the following “speed control delay process” when the brake response delay time tb is longer than the machine response delay time te.

[0076] Fig. Figure 10 is a time diagram used to describe the basic features of the speed control delay process. Fig. 10 is assigned to an example where the brake response delay time tb is longer than the machine response delay time te, similar to in Fig. 5. In Fig. Figure 10 shows a waveform of the change in a target idle speed NEit0 in response to the idle-on request and a waveform of the change in the actual idle speed NEia0 in connection with this change in the target idle speed NEit0, represented by dashed lines.

[0077] The speed control delay process corresponds to a process for delaying the change time of the target idle speed NEit with respect to the time of the idle speed change request (in Fig. 10, time t1) by a speed control delay time tdlyc which is equal to or longer than a difference Δtbe (= tb-te) obtained by subtracting the machine response delay time te from the brake response delay time tb.

[0078] In the present embodiment, the speed control delay time tdlyc is set, for example, to be equal to the difference Δtbe described above. In particular, to calculate the speed control delay time tdlyc, the machine response delay time te and the brake response delay time tb can be obtained in advance, for example, by conducting experiments, and then the difference Δtbe between these can be stored in memory 60b as a fixed value. Furthermore, as already described, the machine response delay time te changes, for example, depending on the machine cooling water temperature, and the brake response delay time tb changes, for example, depending on the brake oil pressure or brake oil temperature.To calculate the speed control delay time tdlyc, the difference Δtbe on board can therefore be calculated as a value, for example, according to the engine cooling water temperature, when the propulsion force change cancellation control is executed.

[0079] In Fig. Figure 10 represents the target idle speed NEitd, which corresponds to the target idle speed NEit after the speed control delay process, represented by a solid line. Time t7 corresponds to the time at which the target idle speed NEitd changes. The associated change in the actual idle speed NEiad begins at time t8, which is delayed from time t7 by the original machine response delay time te. Simultaneously, the change in the actual drive force Fda is also delayed by the speed control delay time tdlyc from the change segment of the actual drive force Fda0, indicated by a dashed line, as shown by the change segment of the actual drive force Fdad, which is indicated by a solid line.

[0080] If the change time t1 of the original target idle speed NEit0 (that is, the time of the idle speed change request) is used as a reference, the machine response delay time increases from the original time te to time te', that is, from time t1 to time t8, due to the execution of the speed control delay process. In other words, the speed control delay process corresponds to the process of delaying the start of the idle speed control by the speed control delay time tdlyc, and as a consequence, it apparently makes the machine response delay time variable.

[0081] The machine response delay time te' after the speed control delay process, using the speed control delay time tdlyc set as described above, is in the Fig. The example shown in Figure 10 is equal to the brake response delay time tb. Therefore, the rotation prediction process can be executed (started) at the time of change t1 of the original target idle speed NEit (that is, at the time of the idle speed change request).

[0082] Furthermore, even if the speed control delay process is as described in the Fig. In the example shown in Figure 10, the predictive speed delay process, the rate limiting process, and the first-order delay process, which are included in the rotational prediction process, are executed based on the original target idle speed NEit0 (that is, the target idle speed before the speed control delay process), which is indicated by the dashed line. Furthermore, the interpolation process is performed based on the change in the predicted idle speed (not shown) after the first-order delay process and the change in the actual idle speed NEia0, which is indicated by the dashed line. Fig. Figure 10 represents the waveform (predicted waveform Wpf) of the change section of the final predicted idle speed NEipf after the interpolation process. Furthermore, in the Fig. In example 10, since the machine response delay time te' after the speed control delay process is equal to the brake response delay time tb, the prediction speed delay time tdlyp used in the prediction speed delay process is equal to zero.

[0083] Furthermore, even if the speed control delay process is carried out, the change section of the predicted driving force Fdp is adjusted according to the change section of the predicted idle speed NEip, as in Fig. Figure 10 shows that the change in braking force Fb is calculated as a result of executing the drive force prediction process. Furthermore, as a result of executing the brake force control process, the change in braking force Fb to cancel the change in calculated predicted drive force Fdp is calculated as the change in target braking force Fbt and instructed at the brake device 30. Moreover, the calculation and instruction of the change in target braking force Fbt are started immediately from time t1 in connection with the start of the rotation prediction process at time t1.

[0084] As previously described, if the brake response delay time tb is longer than the machine response delay time te, the drive force change cancellation control is executed with the speed control delay process. Therefore, similar to the example where the brake response delay time tb is equal to or shorter than the machine response delay time te, the change section of the actual braking force Fba, based on the change section of the predicted idle speed NEip, can be applied to wheels 2 by the rotation prediction process, while the calculation of the change section of the predicted idle speed NEip can be performed. Consequently, the change section of the actual drive force Fda can be appropriately canceled. 2-3. Process by the control device

[0085] Fig. Figure 11 is a flowchart showing a processing routine relating to the automatic parking control in conjunction with the drive force change cancellation control according to the embodiment.

[0086] In the Fig. In the routine shown in Figure 11, the control device 60 first determines in step S10 whether the automatic parking function is activated. The HMI unit 50 includes an automatic parking switch for turning the automatic parking function on and off. The user can activate (switch on) the automatic parking function by pressing the automatic parking switch. If the control device 60 determines that the automatic parking function is activated, it starts the automatic parking control and proceeds to step S20.

[0087] In step S20, the control device 60 executes the target position setting process to set the target parking position PT. This target position setting process can be performed, for example, based on the detection information received by the sensors 40. The sensors 40 include a camera for imaging the area around the vehicle 1. The parking space, which is surrounded by white lines, for example, can be detected by analyzing the image information captured by the camera. The control device 60 automatically sets the target parking position PT, taking into account, for example, the detected parking space and the size of the vehicle 1. The control device 60 can display the detected parking space and the set target parking position PT on the display of the HMI unit 50. The user can then confirm the parking space and target parking position PT displayed on the display.Once the setting of the target parking position PT is complete, the control device 60 proceeds to step S30.

[0088] In step S30, the control device 60 executes the vehicle speed control described above to move the vehicle 1 into the target parking position PT. This step S30 is configured by the processes of steps S302 to S308. In step S302, the control device 60 determines whether or not an idle speed change request is present during the execution of this vehicle speed control. Consequently, if an idle speed change request is present, the control device 60 executes the processes of steps S304 to S308 regarding the drive force change cancellation control until the change in the current drive force Fda in response to the idle speed change request decays. If, on the other hand, no idle speed change request is present, the control device 60 skips steps S304 to S308 and proceeds to step S40.

[0089] During vehicle operation, the longer machine response delay time (te) or brake response delay time (tb) can change. This is because the machine response delay time (te) varies depending on factors such as the machine coolant temperature, and the brake response delay time (tb) varies depending on factors such as brake fluid pressure and temperature. Therefore, in step S304, the control device 60 determines whether the brake response delay time (tb) is longer than the machine response delay time (te).

[0090] If, therefore, the brake response delay time tb is longer than the machine response delay time te, the control device 60 performs the speed control delay process described above in step S306 and then proceeds to step S308. Conversely, if the brake response delay time tb is equal to or shorter than the machine response delay time te, the control device 60 skips step S306 and proceeds to step S308. That is, if the brake response delay time tb is equal to or shorter than the machine response delay time te, the speed control delay process is not executed.

[0091] In step S308, the control device 60 executes the rotation prediction process, the drive force prediction process, and the brake force control process described above. When the drive force change cancellation control is complete (that is, when the change in the actual drive force Fda subsides), the control device 60 proceeds to step S40.

[0092] In step S40, the control device 60 determines whether vehicle 1 has reached the target parking position PT or not. If vehicle 1 has not yet reached the target parking position PT, the control device 60 returns to step S30. If, however, vehicle 1 has reached the target parking position PT, the control device 60 terminates the automatic parking control. 3. Effect

[0093] As described above, the rotation prediction process associated with the drive force change cancellation control according to the present embodiment comprises the "predict speed delay process," the "rate limiting process," and the "first-order delay process." According to the predict speed delay process, the change start time of the predicted idle speed NEip can be combined with the change start time (in Fig. 6A, time t4) of the optimal waveform Wopt can be brought into agreement (at least approximation). According to the rate-limiting process, the slope of the waveform of the change section of the predicted idle speed NEip can be suitably limited, taking into account the response characteristics of the actual idle speed NEia of the internal combustion engine 22, to which the automatic parking control is applied. Furthermore, according to the first-order delay process in the waveform of the change section of the predicted idle speed NEip, the response characteristics of the actual idle speed NEia of the internal combustion engine 22 can be expressed more accurately using the first-order delay.Thus, according to the rotation prediction process of the present embodiment, it is possible to appropriately increase the accuracy of the calculation (prediction) of the change section of the predicted idle speed NEip, which forms the basis of the calculation of the change section of the target braking force Fbt to cancel the vehicle drive force change.

[0094] Furthermore, the rotation prediction process according to the present embodiment includes the "interpolation process." According to the interpolation process, the change interval of the predicted idle speed NEip can be calculated more accurately, while the characteristics of the waveform of the change interval of the actual idle speed NEia are reflected in relation to the waveform of the change interval of the predicted idle speed NEip, based on the waveform of the target idle speed NEit. This makes it possible to improve the accuracy of the calculation (prediction) of the change interval of the predicted idle speed NEip more appropriately.

[0095] Furthermore, the predictive speed delay time tdlyp, used in the predictive speed delay process, is calculated to be longer when the machine cooling water temperature is lower. This allows the predictive speed delay time tdlyp to be adjusted more accurately to account for changes in the machine cooling water temperature. Similarly, the slope S of the waveform of the change section of the predicted idle speed NEip (in Fig. 6B, NEip2), which is constrained by the rate limiting process, is calculated such that it is longer when the machine cooling water temperature is lower. This makes it possible to adjust the slope S more accurately, taking into account changes in the machine cooling water temperature.

[0096] Furthermore, the drive force change cancellation control according to the present embodiment includes the "speed control delay process." Therefore, even if the brake response delay time tb is longer than the machine response delay time te, it is possible to perform automatic parking control (drive force change cancellation control) with the prediction of the idle speed change segment (i.e., with the calculation of the predicted idle speed NEip). In other words, automatic parking control with the prediction of the idle speed change segment can be achieved regardless of whether the brake response delay time tb or the machine response delay time te is longer. 4. Another example of setting the speed control delay time tdlyc

[0097] In the embodiment described above, the speed control delay time tdlyc is set equal to the difference Δtbe (= tb-te) (see Fig. 10) However, instead of this type of example, the speed control delay time tdlyc can also be set longer than the difference Δtbe (in other words, so that the machine response delay time te' after the speed control delay process is longer than the brake response delay time tb). By ensuring a long machine response delay time te' with a range for the brake response delay time tb using this type of setting, the degree of freedom of the calculation can be increased when more accurately calculating the change section of the predicted idle speed NEip with the interpolation process described above. 5. Further examples of the rotation forecasting process

[0098] In the embodiment described above, the rotation prediction process is carried out by combining all processes from the prediction speed delay process, the rate limiting process, the first-order delay process, and the interpolation process. As a result, the change section of the predicted idle speed NEip can be calculated (predicted) more accurately. However, the rotation prediction process according to the present invention can also be carried out without an interpolation process. Furthermore, the rotation prediction process can be carried out with any one or two processes from the prediction speed delay process, the rate limiting process, and the first-order delay process, or it can be a combination of the interpolation process with one or two processes selected in this way.

Claims

[1] Automatic parking control device (60) applied to a vehicle (1) equipped with a drive device (20) and a brake device (30), and configured to perform automatic parking control that automatically moves the vehicle (1) into a target parking position (PT), wherein the drive device (20) comprises an internal combustion engine (22) and a torque converter (24) and is configured to output a vehicle driving force (Fd) transmitted to a wheel (2) of the vehicle (1), wherein the brake device (30) is configured to generate a vehicle braking force (Fb) applied to the wheel (2), wherein the automatic parking control includes a drive force change cancellation control which controls the braking device (30) such that it generates the vehicle braking force (Fb) which cancels a change in the vehicle drive force (Fd) in connection with a change in an actual idle speed (NEi) of the internal combustion engine (22) when a target idle speed (NEit) changes in response to an idle speed change request, wherein the automatic parking control device (60) is configured such that it is in the drive force change cancellation control: executes a rotation prediction process to calculate a change section of a predicted idle speed corresponding to a change section of an idle speed (NEip) obtained by advancing a change section of the actual idle speed (NEia) in association with a change in the target idle speed (NEit) by a brake response delay time (tb) from a time at which a target vehicle braking force (Fbt) is directed to the brake device (30) to a time at which a change in the vehicle braking force (Fb) begins; executes a drive force prediction process to calculate a change section of a predicted drive force corresponding to a change section of the vehicle drive force (Fdp) according to the change section of the predicted idle speed; executes a brake force control process to calculate a change section of the vehicle brake force (Fb) as a change section of the target vehicle brake force (Fbt), which cancels out the change section of the predicted drive force, and to direct a calculated vehicle brake force change section to the brake device (30); and If the brake response delay time (tb) is longer than a machine response delay time (te) corresponding to a response delay time of the actual idle speed (NEia) with respect to the change in the target idle speed (NEit), a speed control delay process is performed to delay the change in the target idle speed (NEit) by a speed control delay time (tdlyc) starting from a time at which the idle speed change request is issued, wherein the speed control delay time (tdlyc) is greater than or equal to a difference (Δtbe) obtained by subtracting the machine response delay time (te) from the brake response delay time (tb). [2] Automatic parking control device (60) according to claim 1, wherein the rotation prediction process comprises at least one process consisting of a prediction speed delay process, a rate limiting process and a first-order delay process to calculate a waveform of the change section of the predicted idle speed based on a waveform of the target idle speed (NEit), The forecast speed delay process delays a change start time of the waveform of the change section of the forecast idle speed, so that it is delayed from a change start time of the waveform of the target idle speed (NEit) by a forecast speed delay time (tdlyp) corresponding to a difference obtained by subtracting the brake response delay time (tb) from the machine response delay time (te). The rate-limiting process delays a slope (S) of the waveform of the change section of the predicted idle speed such that it is equal to or less than a maximum slope of the change in the actual idle speed (NEia) that can be generated by the internal combustion engine (22), and The first-order delay process is applied to a waveform of the target idle speed (NEit) without any process from the forecast speed delay process and the rate limiting process, or to a waveform of the change section of the forecasted idle speed after the forecast speed delay process and / or the rate limiting process. [3] Automatic parking control device (60) applied to a vehicle (1) equipped with a drive device (20) and a brake device (30), and configured to perform automatic parking control that automatically moves the vehicle (1) into a target parking position (PT), wherein the drive device (20) comprises an internal combustion engine (22) and a torque converter (24) and is configured to output a vehicle driving force (Fd) transmitted to a wheel (2) of the vehicle (1), wherein the brake device (30) is configured to generate a vehicle braking force (Fb) applied to the wheel (2), wherein the automatic parking control includes a drive force change cancellation control which controls the braking device (30) such that it generates the vehicle braking force (Fb) which cancels a change in the vehicle drive force (Fd) in connection with a change in an actual idle speed (NEi) of the internal combustion engine (22) when a target idle speed (NEit) changes in response to an idle speed change request, wherein the automatic parking control device (60) is configured such that it is in the drive force change cancellation control: executes a rotation prediction process to calculate a change section of a predicted idle speed corresponding to a change section of an idle speed (NEip) obtained by advancing a change section of the actual idle speed (NEia) in association with a change in the target idle speed (NEit) by a brake response delay time (tb) from a time at which a target vehicle braking force (Fbt) is directed to the brake device (30) to a time at which a change in the vehicle braking force (Fb) begins; executes a drive force prediction process to calculate a change section of a predicted drive force corresponding to a change section of the vehicle drive force (Fdp) according to the change section of the predicted idle speed; and executes a brake force control process to calculate a change section of the vehicle brake force (Fb) as a change section of the target vehicle brake force (Fbt) which cancels the change section of the predicted drive force, and to direct a calculated vehicle brake force change section to the brake device (30), wherein The rotation prediction process includes at least one process consisting of a prediction speed delay process, a rate limiting process, and a first-order delay process to calculate a waveform of the change section of the predicted idle speed based on a waveform of the target idle speed (NEit). The predictive speed delay process delays a change start time of the waveform of the change section of the predicted idle speed such that it is delayed from a change start time of the waveform of the target idle speed (NEit) by a predictive speed delay time (tdlyp), which corresponds to a difference obtained by subtracting the brake response delay time (tb) from a machine response delay time (te), which corresponds to a response delay time of the actual idle speed (NEia) with respect to the change in the target idle speed (NEit). The rate-limiting process delays the slope (S) of the waveform of the change section of the predicted idle speed such that it is equal to or less than a maximum slope of the change in the actual idle speed (NEia) that can be generated by the internal combustion engine (22), and The first-order delay process is applied to a waveform of the target idle speed (NEit) without any process from the forecast speed delay process and the rate limiting process, or to a waveform of the change section of the forecasted idle speed after the forecast speed delay process and / or the rate limiting process. [4] Automatic parking control device (60) according to claim 2 or 3, wherein the rotation prediction process includes all processes from the prediction speed delay process, the rate limiting process and the first-order delay process. [5] Automatic parking control device (60) according to one of claims 2 to 4, wherein the rotation prediction process comprises an interpolation process to calculate a change section of a final predicted idle speed by interpolation for each time step based on the change section of the predicted idle speed after at least one process from the prediction speed delay process, the rate limiting process and the first-order delay process, and the change section of the actual idle speed (NEia) in association with the change of the target idle speed (NEit). [6] Automatic parking control device (60) according to one of claims 2 to 5, wherein the predicted speed delay time (tdlyp) is longer when the coolant temperature of the internal combustion engine (22) is lower. [7] Automatic parking control device (60) according to one of claims 2 to 6, wherein the slope (S) of the waveform of the change section of the predicted idle speed after a restriction by the rate limiting process is smaller when a cooling water temperature of the internal combustion engine (22) is lower.

Images