Adaptive Cruise Control for Motor Vehicles

Abstract

Such an adaptive cruise controller (26) for a motor vehicle (2) comprises a detection module (28) for detecting a leading vehicle, a setting module (30) capable of establishing a setpoint, a storage module (32) configured to store a value corresponding to the setpoint, a timer (34) configured to be initialized and activated at the instant the vehicle stops, and a reinitialization module (72) for reinitializing the storage module (32). The cruise controller (26) comprises an establishment module (36) capable of determining a limit according to the environment of the vehicle (2), and the reinitialization module (72) is configured to reinitialize the value stored by the storage module (32) when the duration provided by the timer (34) is greater than the limit.

Description

Field of the Invention

[0001] The present invention relates to the field of adaptive cruise control for motor vehicles and more particularly to adaptive speed control or adaptive distance control. Background Art

[0002] Devices for assisting the driving of motor vehicles include an adaptive cruise controller, which is also known by the term "adaptive cruise control stop-and-go system" or the corresponding acronym "ACCS&G". The adaptive cruise controller incorporated in the following vehicle makes it possible to control the cruise of the following vehicle by taking into account the leading vehicle located in front of the following vehicle. The expression "control the cruise" should be understood to mean controlling the speed of the following vehicle or the distance between the following vehicle and the leading vehicle. When the leading vehicle stops, the adaptive cruise controller detects this stop and commands the following vehicle to stop. When the leading vehicle restarts, the adaptive cruise controller stops commanding the following vehicle to stop.

[0003] In a conventional manner, the adaptive command controller is capable of storing a control setpoint before the moment when the following vehicle stops. When the leading vehicle restarts, the control resumes with the stored setpoint. For example, the adaptive cruise controller saves in memory a setpoint for activating the speed control of the following vehicle at a setpoint speed. When the leading vehicle restarts, the speed control is automatically activated at the setpoint speed.

[0004] However, such a design is not entirely satisfactory. In fact, when the leading vehicle stops at a traffic light, a stop sign or a roundabout, resuming control with the stored setpoint can create dangerous situations, such as not stopping at a traffic light, a stop sign without a stop marking or violating priority rules.

[0005] To mitigate these drawbacks, it has been proposed to reinitialize the stored setpoint when the leading vehicle stops for a period exceeding a limit on the order of a few seconds.

[0006] Although this solution makes it possible to limit the risks accidentally caused by storing the setpoint, this solution limits the driver's ability to reactivate the control in situations where there is no specific danger (such as in stop-and-go situations on a highway). Summary of the Invention

[0007] In view of the foregoing, an object of the present invention is to allow an adaptive cruise control that can mitigate the above-mentioned drawbacks.

[0008] More specifically, an object of the present invention is to limit the risks associated with the storage of the setpoint of the adaptive cruise control while avoiding forcing the driver to reactivate the control in situations where there is little or no danger.

[0009] To this end, an adaptive cruise controller for a motor vehicle is proposed, which includes a detection module for detecting a leading vehicle, a setting module capable of formulating a setpoint, a storage module configured to store values corresponding to the setpoint, a timer configured to be initialized and actuated at the instant the vehicle stops, and a reinitialization module for reinitializing the storage module.

[0010] According to one of its general characteristics, the controller includes an establishment module capable of determining a limit according to the environment of the vehicle, and the reinitialization module is configured to reinitialize the value stored by the storage module when the duration delivered by the timer is greater than the limit.

[0011] The establishment module enables the establishment of limit values according to the environment on which the vehicle is traveling. Therefore, the rapidity of reinitializing the stored setpoint is related to the estimation of the degree of danger caused by the vehicle.

[0012] According to one embodiment, the establishment module includes a determination module capable of determining the environment of the vehicle and a map containing limit values depending on the environment.

[0013] Advantageously, the setting module is capable of formulating at least one setpoint selected from the following: a speed control activation setpoint, a control speed setpoint, an activation setpoint for distance control relative to the leading vehicle, and a control distance setpoint.

[0014] Advantageously, the determination module is configured to determine the environment selected from the following: urban environment, suburban environment, rural environment, expressway environment, and highway environment.

[0015] Preferably, the determination module includes at least one device selected from the following: ultrasonic sensor, radar, lidar, camera, inertial measurement unit, odometer, satellite-based global positioning device.

[0016] Such devices are equipment that are usually already incorporated in motor vehicles. The production cost of the adaptive cruise controller is thus limited.

[0017] In one embodiment, the determination module includes at least one recognition unit selected from the following: a recognition unit for another vehicle, a pedestrian recognition unit, a road infrastructure recognition unit, a road geometry recognition unit, and a meteorological condition recognition unit.

[0018] Advantageously, the determination module is capable of recognizing at least one highway or expressway symbol selected from a highway section start sign, a main network route panel, and an auxiliary network route panel, and is configured to determine the environment as a road environment when a highway or expressway symbol is recognized.

[0019] In one embodiment, the determining module is capable of recognizing at least one urban symbol selected from a building density area entry sign, a bicycle lane notice sign, and a crosswalk notice sign, and is configured to determine that the environment is an urban environment when the urban symbol is recognized.

[0020] In another embodiment, the determining module is capable of recognizing at least one hazard symbol selected from a roundabout sign, a stop sign, and a traffic signal notice sign, and is configured to determine that the environment is a hazardous environment when the hazard symbol is recognized.

[0021] Advantageously, the establishing module selects a limit between 25 seconds and 35 seconds in the case of a road environment, a limit between 2 seconds and 4 seconds in the case of an urban environment, and a limit less than 0.1 second in the case of a hazardous environment.

[0022] The limits selected within these value intervals are particularly suitable for limiting the hazards accidentally caused by storing setpoints while avoiding reinitialization in cases where there is little or no hazard.

[0023] According to another aspect, a method for adaptive cruise control of a motor vehicle is proposed, in which a leading vehicle is detected, a setpoint is formulated, a value corresponding to the setpoint is stored before the instant when the vehicle stops, the environment of the vehicle is determined, and the stored value is reinitialized according to the determined environment.

[0024] In one implementation mode, a timer is actuated from the instant of stopping, a limit is calculated according to the environment of the vehicle, and the stored value is reinitialized when the duration delivered by the timer is greater than the limit. Description of the Drawings

[0025] Other objects, features, and advantages of the present invention will become apparent by reading the following description given solely by way of non-limiting example and with reference to the accompanying drawings, in which:

[0026] - Figure 1 is a schematic view of a motor vehicle incorporating a controller according to one aspect of the present invention,

[0027] - Figure 2 is Figure 1 a schematic representation of the controller of the vehicle,

[0028] - Figure 3 shows examples of highway symbols and freeway symbols,

[0029] - Figure 4 shows examples of urban symbols,

[0030] -Figure 5 shows an example of a danger symbol, and

[0031] - Figure 6 shows a method for performing adaptive cruise control according to another aspect of the present invention. Detailed implementation

[0032] Reference Figure 1 , schematically shows a motor vehicle 2. The vehicle 2 includes a front end 4 and a rear end 6.

[0033] In this patent application, the terms "front" and "rear" will be understood to refer to the front end 4 and the rear end 6 of the vehicle 2. Similarly, the terms "longitudinal", "lateral", "left" and "right" will be understood by considering the longitudinal direction connecting the ends 4 and 6 of the vehicle 2 as a whole.

[0034] The vehicle 2 includes a body shell 8, an on-vehicle computer 10, a driver interface 11, and a satellite-based global positioning system 12 (also referred to as the term "global navigation satellite system" and the corresponding acronym "GNSS"), such as, for example, the "Global Positioning System" known by the corresponding acronym "GPS".

[0035] In addition, the vehicle 2 includes a radar 14, a lidar 16, an ultrasonic sensor 18, and a camera 20. The components 14, 16, 18, and 20 are arranged near the front end 4 of the vehicle 2 (for example, arranged in the radiator grille, the ventilation hood grille), in the area near the windshield or fenders of the vehicle 2. In this way, the components 14, 16, 18, and 20 acquire images representing the environment of the vehicle 2, especially the environment in front of the vehicle 2.

[0036] The vehicle 2 includes an odometer 22 and an inertial measurement unit 24. The odometer 22 and the inertial measurement unit 24 are information-linked with the on-vehicle computer 10 and are capable of providing information such as the relative position or acceleration of the vehicle 2. The odometer 22 and the on-vehicle computer 10 can determine the speed V of the vehicle 2 VEH .

[0037] The vehicle 2 includes an adaptive cruise controller 26. In the example shown, the controller 26 implements the control of the speed V VEH and the control of the distance Δ relative to a leading vehicle (not shown). However, without departing from the scope of the present invention, of course, an adaptive cruise controller that implements only one of these two functions can be envisaged. Figure 2 The controller 26 is schematically shown in.

[0038] Reference Figure 2, the controller 26 includes a positioning system 12, a radar 14, a lidar 16, an ultrasonic sensor 18, a camera 20, an odometer 22, and an inertial measurement unit 24. Components 12, 14, 16, 18, 20, 22, and 24 together constitute a detection module 28, which is designed to detect the presence of a leading vehicle (not shown) and the position of the leading vehicle relative to vehicle 2.

[0039] The controller 26 includes a formulation module 30. Module 30 is information-linked with module 28 and the on-board computer 10. The function of module 30 is to formulate setpoints based on the operating parameters of vehicle 2, the intentions of the driver of vehicle 2, and the presence and position of the leading vehicle.

[0040] More specifically, module 30 formulates a setpoint CONS_1 that activates the control of speed V VEH If the control of speed V VEH must be implemented, the setpoint CONS_1 takes the value "yes", otherwise it takes the value "no".

[0041] Module 30 generates a control speed setpoint CONS_2. The setpoint CONS_2 can take any speed value that vehicle 2 can reach. More specifically, module 30 collects the setpoint CONS_2 from the on-board computer 10 and the input interface 11.

[0042] Module 30 formulates a setpoint CONS_3 that activates the control of distance Δ. If the control of distance Δ must be implemented, the setpoint CONS_3 takes the value "yes", otherwise it takes the value "no". If the detection module 28 does not detect the presence of the leading vehicle, the setpoint CONS_3 is forced to the value "no".

[0043] The formulation module 30 generates a setpoint CONS_4 for the control distance between vehicle 2 and the leading vehicle. The setpoint CONS_4 can take any distance value smaller than the maximum range of the optical sensors 14, 16, 18, and 20. In the example shown, the value of the setpoint CONS_4 is calculated based on speed V VEH

[0044] The setpoints CONS_1, CONS_2, CONS_3, and CONS_4 are sent to a traction command device (not shown) of vehicle 2. The traction command device drives the powertrain (not shown) of vehicle 2 in such a way that vehicle 2 moves according to the setpoints CONS_1, CONS_2, CONS_3, and CONS_4. In other words, the traction command device drives the powertrain in such a way that:

[0045] - If CONS_1 = "yes", then speed V VEH converges to CONS_2, and ​

[0046] - If CONS_3 = "Yes", then the distance Δ converges to CONS_4.

[0047] Modules 28 and 30 are equipped with hardware and software means for detecting a significant deceleration or a complete stop of the lead vehicle. When a significant deceleration or a complete stop of the lead vehicle is detected, module 30 issues a storage signal MEMO. Thereafter, module 30 adapts the setpoints CONS_1, CONS_2, CONS_3, and CONS_4 so that vehicle 2 gradually stops.

[0048] Controller 26 includes a storage module 32. Module 32 is information - linked to module 30. More specifically, at each rising edge of the signal MEMO issued by module 30, module 32 stores the values of the setpoints CONS_1, CONS_2, CONS_3, and CONS_4 issued by module 30.

[0049] Controller 26 includes a timer 34 that is information - linked to the on - vehicle computer 10. More specifically, timer 34 is configured to initialize itself to zero and trigger once the speed V VEH becomes zero. When timer 34 is triggered, the timer displays the elapsed time t since the moment of triggering.

[0050] Controller 26 includes an establishment module 36. Establishment module 36 includes a determination module 38 and a map 40. In the example shown, module 38 particularly includes the detection module 28.

[0051] Determination module 38 includes an identification unit 42 for another vehicle, a pedestrian identification unit 44, a road geometry identification unit 46, a road infrastructure identification unit 48, and a meteorological condition identification unit 50. Units 42, 44, 46, 48, and 50 are information - linked to module 28. More specifically, units 42, 44, 46, 48, and 50 are equipped with hardware and software means for processing the images captured by components 14, 16, 18, and 20 of module 28 and the information collected by components 22 and 24 of module 28. Based on these images and this information, units 42, 44, 46, 48, and 50 identify data representing the degree of danger caused by vehicle 2.

[0052] In the example shown, unit 48 is equipped with hardware and software means for identifying road signs characterizing the environment of vehicle 2. An example of such a road sign is shown in Figures 3 to 5 .

[0053] Unit 48 is configured to identify the highway section start sign 52, the national route panel 54, and the regional route panel 56. If unit 48 identifies sign 52, 54, or 56, module 38 emits signal ROAD_ENVIR. Thus, module 38 is able to detect that vehicle 2 is traveling in a road environment (such as, a roundabout or a bypass), that is, traveling on a highway, a freeway, a main road in a rural setting, or a main road in a suburban setting.

[0054] In addition, unit 48 is configured to identify the built-up area entry sign 58, the bicycle lane notice sign 60, and the crosswalk notice sign 62. If unit 48 identifies sign 58, 60, or 62, module 38 emits signal URBAN_ENVIR. Thus, module 38 is able to detect that vehicle 2 is traveling in an urban environment, that is, especially traveling on the streets of a town.

[0055] Unit 48 is configured to identify the notice sign 64 for a specific event, the roundabout indication sign 66, the stop sign 68 (also known as the term "STOP" sign), and the traffic signal notice sign 70. If unit 48 identifies symbol 64, 66, 68, or 70, module 38 emits signal DANGER_ENVIR. Thus, module 38 is able to detect that vehicle 2 is traveling in a dangerous environment, that is, especially traveling near an intersection or a level crossing in an urban setting, a suburban setting, or a rural setting.

[0056] In the example shown, unit 48 is configured to identify the shapes, sizes, colors, and characters written on signs 52, 54, 56, 58, 60, 62, 64, 66, 68, and 70. Although unit 48 is specifically configured to identify Figures 3 to 5 the signs corresponding to the norms of the French highway code as represented, it is obvious that, without departing from the scope of the present invention, unit 48 can be configured to identify other signs, especially signs corresponding to the laws of another country in which vehicle 2 intends to travel.

[0057] When none of the above signs can be identified or when the above signs are identified with too significant an error tolerance, determination module 38 is configured to consider the data analyzed by units 42, 44, 46, and 50.

[0058] More specifically, unit 42 collects the images captured by radar 14, lidar 16, ultrasonic sensor 18, and camera 20 to identify the presence and location of other vehicles in the environment of vehicle 2. Unit 44 collects the same images as unit 42 to detect the presence of pedestrians near vehicle 2. If a large number of vehicles and / or pedestrians are identified, module 38 emits signal URBAN_ENVIR.

[0059] Unit 46 collects the information provided by the positioning system 12, the odometer 22, and the inertial measurement unit 24, as well as the images captured by the radar 14, the lidar 16, the ultrasonic sensors 18, and the camera 20 to identify specific road geometries. In particular, unit 46 can detect lanes presenting the shape of a roundabout, lanes presenting a slope, lanes presenting the shape of a highway on-ramp, and lanes presenting the shape of an intersection. Based on the road geometries detected by unit 46, module 38 emits different signals ROAD_ENVIR, URBAN_ENVIR, or DANGER_ENVIR.

[0060] Unit 50 collects the images captured by the radar 14, the lidar 16, the ultrasonic sensors 18, and the camera 20, as well as the information emitted by the odometer 22 and the inertial measurement unit 24 to identify specific weather conditions. For example, if unit 50 detects weather conditions of rain or snow, module 38 emits a different signal DANGER_ENVIR.

[0061] Map 40 is linked for information with module 38. More specifically, map 40 collects the signals ROAD_ENVIR, URBAN_ENVIR, or DANGER_ENVIR emitted by module 38. Map 40 transmits the value of the time limit LIM based on the collected signals. In the example shown, map 40 delivers:

[0062] - When the input signal ROAD_ENVIR is taken as input, the limit LIM is between 25 seconds and 35 seconds, preferably substantially 30 seconds,

[0063] - When the input signal URBAN_ENVIR is taken as input, the limit LIM is between 2 seconds and 4 seconds, preferably substantially 3 seconds, and

[0064] - When the input signal DANGER_ENVIR is taken as input, the limit LIM is strictly less than 0.1 second, preferably substantially 0 second.

[0065] The controller 26 includes a reinitialization module 72 that is information - linked to the module 32, the timer 34, and the map 40. More precisely, the module 72 is capable of collecting the limit LIM. In addition, the module 72 is capable of collecting the duration t displayed by the timer 34. The module 72 is capable of emitting a signal REINIT for re - initializing the storage module 32. The module 72 is configured to emit the signal REINIT once the duration t exceeds the limit LIM. When the module 32 receives the signal REINIT, the stored set - points CONS_1, CONS_2, CONS_3, and CONS_4 are re - initialized. More specifically, when the module 32 receives the signal REINIT, the set - points CONS_1 and CONS_3 take the value "no".

[0066] Reference Figure 6 Schematically represents a method for implementing adaptive cruise control that can be implemented by means of the controller 26.

[0067] The method includes a re - initialization step E00. During step E00, the vehicle 2 travels at a speed V VEH_E00 and the controller 26 is activated by the driver.

[0068] The method includes a step E01 of establishing a first set - point and a second set - point. More precisely, during step E01, the set - point CONS_1 takes the value "yes". The set - point CONS_2 takes a value equal to the speed V VEH_E00 .

[0069] The method includes a step E02 of implementing control of the speed V VEH to tend to make it converge to the speed V VEH_E00 .

[0070] Thereafter, the method includes a test step E03, during which it is detected whether there is a vehicle in the lane of the vehicle 2 and in front of the vehicle 2. When the response to step E03 is "no", step E02 is continued. If the response is "yes" when step E03 is completed, step E04 is applied.

[0071] During step E04, the values of the set - points CONS_1, CONS_3, and CONS_4 are modified. More precisely, the set - point CONS_l takes the value "no", the set - point CONS_3 takes the value "yes", and the set - point CONS_4 takes a value Δ VEH proportional to the speed V E04 .

[0072] The method includes step E05, during which the distance Δ is controlled in such a way that the distance converges to Δ E04Although in the exemplary embodiments shown, the switch from speed control to distance control is made after detecting the presence of a leading vehicle, regardless of the driver's intention, other modes that drive the switch from speed control to distance control (and vice versa) can be provided without departing from the scope of the present invention. For example, the switch from one type of control to another can be made after an action by the driver on the interface 11.

[0073] The method includes a test step E06. During step E06, it is detected whether the leading vehicle significantly decelerates or stops. If no significant deceleration or stop of the leading vehicle is detected during step E06, step E05 is repeated. If a stop or significant deceleration of the leading vehicle is detected upon completion of step E06, step E07 is applied.

[0074] During step E07, a signal MEMO is emitted and the module 32 stores the setpoints CONS_1, CONS_2, CONS_3, and CONS_4.

[0075] The method includes a step E08 of stopping the vehicle 2. During step E08, the traction command device is driven in a manner that stops the vehicle 2. When the vehicle 2 has stopped, the timer 34 is initialized and actuated. Then step E08 is terminated.

[0076] The method includes a test step E09, during which it is determined whether the leading vehicle restarts. As long as the response is "no", step E09 is repeated. Once the response to step E09 is "yes", step E10 is applied.

[0077] During step E10, the limit LIM corresponding to the environment in which the vehicle 2 is traveling, delivered by the map 40, is collected.

[0078] The method includes a test step E11 of comparing the limit LIM with the value t displayed by the timer 34. More precisely, in step 11:

[0079] - If t < LIM, distance control is resumed by applying step E05, and

[0080] - If t > LIM, step E12 is applied.

[0081] During step E12, the module 72 emits a signal REINIT. Accordingly, the module 32 is reinitialized, that is, the setpoints CONS_1 and CONS_3 take the value "no". Upon completion of step E12, the method terminates.

[0082] In the exemplary embodiment shown, the choice of reinitialization depends directly on the comparison between the value t and the limit LIM which can take various values. However, the scope of the invention is not departed from by envisioning other driving modes. For example, step E12 can be directly implemented starting from the signal DANGER_ENVIR emitted by module 38. Additionally, steps E10 and E11 can be replaced by a test step during which two tests are carried out simultaneously, namely determining whether the signal URBAN_ENVIR has been emitted and whether the value t exceeds 2 seconds, or whether the signal ROAD_ENVIR has been emitted and whether the value t exceeds 30 seconds. In other words, such a step can be written as:

[0083] [{URBAN_ENVIR has been emitted and t ≥ 2 seconds}

[0084] or {ROAD_ENVIR has been emitted and t ≥ 30 seconds}]

[0085] If the response to this test step is yes, step E12 is applied. Otherwise, the cruise control is restored with the stored setpoint.

[0086] In view of the foregoing, with the aid of the controller 26 and the control method according to the invention, adaptive cruise control can be implemented while limiting the risk associated with storing the setpoint in dangerous situations (such as intersections with traffic lights), yet without restricting the driver from reactivating the control in situations with little or no danger (such as stop-and-go traffic on a highway).

Claims

1. An adaptive cruise controller (26) for a motor vehicle (2), the adaptive cruise controller comprising a detection module (28) for detecting a leading vehicle, a setting module (30) capable of formulating a setpoint, a storage module (32) configured to store a value corresponding to the setpoint, a timer (34) configured to be initialized and actuated at the instant the motor vehicle stops, and a reinitialization module (72) for reinitializing the storage module (32). Characterized in that, the adaptive cruise controller comprises an establishment module (36) capable of determining a limit (LIM) according to the vehicle environment in which the motor vehicle (2) is traveling, the establishment module comprising a determination module capable of determining the vehicle environment, and the reinitialization module (72) is configured to reinitialize the value stored by the storage module (32) when the duration (t) delivered by the timer (34) is greater than the limit (LIM).

2. The adaptive cruise controller (26) according to claim 1, wherein, the setting module (30) is capable of formulating at least one setpoint selected from the following: a speed control activation setpoint (CONS_1), a control speed setpoint (CONS_2), an activation setpoint (CONS_3) for distance control relative to the leading vehicle, and a control distance setpoint (CONS_4).

3. The adaptive cruise controller (26) according to claim 2, wherein, the establishment module (36) comprises a map (40) containing limit (LIM) values depending on the environment.

4. The adaptive cruise controller (26) according to claim 2 or 3, wherein, the determination module (38) comprises at least one device selected from the following: an ultrasonic sensor (18), a radar (14), a lidar (16), a camera (20), an inertial measurement unit (24), an odometer (22), a satellite-based global positioning device (12).

5. The adaptive cruise controller (26) according to any one of claims 1 to 3, wherein, the determination module (38) comprises at least one identification unit selected from the following: an identification unit for another vehicle, a pedestrian identification unit (44), a road infrastructure identification unit (48), a road geometry identification unit (46), and a meteorological condition identification unit (50).

6. The adaptive cruise controller (26) according to any one of claims 1 to 3, wherein, the determination module (38) is capable of identifying at least one highway or expressway symbol selected from a highway section start sign (52), a main network route panel (54), and an auxiliary network route panel (56), and is configured to determine the environment as a road environment when a highway or expressway symbol is identified.

7. The adaptive cruise controller (26) according to any one of claims 1 to 3, wherein, The determination module (38) is capable of recognizing at least one urban symbol selected from an urban area entry sign (58), a bicycle lane notice sign (60), and a crosswalk notice sign (62), and is configured to determine that the environment is an urban environment when the urban symbol is recognized.

8. The adaptive cruise controller (26) according to any one of claims 1 to 3, wherein the determination module (38) is capable of recognizing at least one hazard symbol selected from a roundabout indication sign (66), a stop sign (68), and a traffic signal notice sign (70), and is configured to determine that the environment is a hazardous environment when the hazard symbol is recognized.

9. The adaptive cruise controller (26) according to any one of claims 1 to 3, wherein the establishment module (36) selects a limit between 25 seconds and 35 seconds in the case of a road environment, selects a limit between 2 seconds and 4 seconds in the case of an urban environment, and selects a limit less than 0.1 second in the case of a hazardous environment.

10. A method for adaptive cruise control of a motor vehicle, wherein a leading vehicle (E03, E06, E09) is detected, a setpoint (E01, E04) is formulated, a value (E07) corresponding to the setpoint is stored before the moment when the motor vehicle stops, a timer (34) is initialized and actuated at the moment when the motor vehicle stops, the vehicle environment (E10) in which the motor vehicle is traveling is determined, a limit (LIM) is determined according to the vehicle environment determined for the motor vehicle, and the stored value (E12) is reinitialized when the duration (t) delivered by the timer (34) is greater than the limit (LIM).

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