Method for controlling a motor vehicle - Patents.com

Abstract

The present invention relates to a method for autonomously controlling actuators (15) of a control system of an autonomous propulsion device (10), comprising the steps of: determining a reference trajectory (T0), determining the position of said device relative to the reference trajectory, obtaining parameters (Cc) related to the forces exerted by the driver on manual controls of said control system, and calculating, by a computer, control commands (Cr) for said actuators. According to the invention, control setpoints are calculated as a function of said parameters and the position of said device relative to the reference trajectory.

Description

[Technical field]

[0001] The present invention relates generally to automating autonomous device trajectory tracking.

[0002] The invention is particularly advantageous in the context of motor vehicle driving assistance, but the invention may also find application in the fields of aeronautics or robotics.

[0003] The present invention more particularly relates to a method for autonomously controlling actuators of a control system of an automotive device, comprising: - determining a reference trajectory; - determining the position of said device relative to a reference trajectory; - obtaining parameters related to the force applied by a driver to a manual control of said control system; - calculating, by a computer, a control set point for said actuator; The present invention relates to a method, including

[0004] The invention further relates to a device equipped with a computer adapted to carry out this method. [Background technology]

[0005] For safety reasons, motor vehicles are increasingly being equipped with driver assistance or autonomous driving systems.

[0006] Among these systems, particularly known are Automatic Emergency Braking (AEB) systems, which are designed to avoid any collision with an obstacle located in the lane taken by the vehicle, by simply acting on the conventional braking system of the motor vehicle.

[0007] However, there are situations in which these emergency braking systems do not make it possible to avoid a collision or are simply not available (for example when a vehicle is closely following a motor vehicle).

[0008] For these situations, automatic avoidance systems (better known by the abbreviation AES, which stands for "Automatic Evasive Steering" or "Automatic Emergency Steering") have been developed that make it possible to avoid an obstacle by deflecting the vehicle from the obstacle's trajectory, either by acting on the steering of the vehicle or by acting on the vehicle's differential braking system.

[0009] It may happen that this AES system for obstacle avoidance conflicts with the driver, forcing the vehicle to follow a different avoidance trajectory than the driver wanted to take, the result of which is at best a nuisance for the driver (who then dares to deactivate the AES system, compromising his safety) and at worst a lack of understanding for the driver, which potentially causes him to have an insufficient understanding of the situation.

[0010] Managing the interaction between the driver and this AES system therefore proves difficult in practice. Summary of the Invention

[0011] Therefore, the present invention proposes to enhance existing AES systems by adding additional functions to them that ensure a better reconciliation between the driver's wishes and the decisions taken by the AES system.

[0012] More particularly, according to the invention, a method as defined in the introduction is proposed, in which a control setpoint is calculated as a function of said parameter and as a function of the position of said device relative to a reference trajectory.

[0013] Thus, thanks to the invention, the trajectory taken by the autonomous device depends not only on the setpoints generated by the AES system, but also on the intentions expressed by the driver.

[0014] The invention then makes it possible to mediate and favour the will expressed by the AES system or by the driver as a function of the situation encountered, and in particular as a function of the position of the automotive device relative to obstacles.

[0015] The invention thus makes it possible to avoid placing the driver in a situation of ignorance, whilst guaranteeing him the best possible driving comfort.

[0016] Other advantageous and non-limiting features of the control method according to the invention, taken individually or according to all technically possible combinations, are the following: - the device is a motor vehicle suitable for travelling on a road and including at least one drive wheel; - the manual control means is a steering wheel; - the control system enables each drive wheel to be steered; - the parameter relates to the torque applied to the steering wheels by the driver of the motor vehicle, - The reference trajectory is determined so that the device avoids obstacles, - at least two zones of the environment of the device are taken into account, the limits of which depend on the position of an obstacle and / or on the position of a reference trajectory relative to an obstacle, and the calculation of the control setpoints is performed by determining the zone in which the device is located and then by using an algorithm for calculating a control setpoint that is selected as a function of the zone in which the device is located, - providing for determining an indicator, the value of which depends on the area in which the device is located and on the parameter; providing for generating preliminary control setpoints for the actuators, making it possible to steer the device on a reference trajectory; providing for correcting the preliminary setpoints as a function of the value of the indicator; - the indicator is adapted to take only one or the other of two values, and provision is made for determining a correction indicator as a function of the indicator, the correction indicator fluctuating between the two values, and the preliminary setpoint is corrected by multiplying the value of the preliminary setpoint by the value of the correction indicator, - when the correction indicator is varied, a rate of variation of the correction indicator is determined as a function of a speed of the motor vehicle and a radius of curvature of a road such that a lateral acceleration of the motor vehicle does not exceed a determined threshold; - preliminary setpoints are derived from wheel steering angle setpoints, which themselves are calculated as a function of the position of said device relative to a reference trajectory and filtered by means of a controller satisfying a setpoint amplitude limit model and a setpoint variation limit model; - the computer considers four regions associated with four different calculation algorithms, the four regions being: * an area between the reference trajectory and a guard line, located upstream of the obstacle, beyond which any collision with the obstacle is avoided; *The area between the reference track and the guard line, alongside the obstacle and downstream of the obstacle; *The area located on the opposite side of the reference track from the protection line and upstream of the obstacle, and A zone, a part of which is located upstream of an obstacle on the opposite side of the guard line from the reference track, and another part of which is located downstream of the obstacle alongside the obstacle on the opposite side of the guard line from the reference track. and - when the device moves from the first area to the second area, the computer continues to use the algorithm associated with the first area as long as the device has not progressed beyond a hysteresis trajectory determined as a function of a reference trajectory; the reference trajectory is determined so as to avoid the obstacle by avoiding at least one protection limit located around a portion of the obstacle, the first protection limit has a shape and a position which are a function of the shape of the obstacle and / or of the sensors with which the motor vehicle is equipped, of the measurement errors of the sensors and / or of the speed of the obstacle, The second protection limit has a shape and a location that is a function of a predetermined safety margin.

[0017] The invention further proposes an autonomous device, such as a car, comprising at least one actuator adapted to influence the trajectory of said device and a computer for controlling said actuator, the computer being programmed to implement the method as specified above.

[0018] Naturally, the various features of the invention can be associated with one another according to various combinations, unless those features are mutually exclusive or incompatible.

[0019] The description given below, given by way of non-limiting example in the light of the attached drawings, will give a good understanding of what the invention consists of and how it can be produced.

[0020] In the accompanying drawings: [Brief description of the drawings]

[0021] [Figure 1]1 is a schematic top view of a motor vehicle traveling on a road on which is depicted an avoidance trajectory that the vehicle must take. [Diagram 2] FIG. 1 is a block diagram illustrating the architecture of a control system suitable for implementing the control method according to the invention. [Diagram 3] 2 is a schematic view of the motor vehicle of FIG. 1, of the different zones of obstacles, of the obstacle avoidance trajectory of the motor vehicle and used in the context of the control method according to the invention; FIG. [Figure 4] FIG. 2 is a schematic representation of an obstacle, an obstacle avoidance trajectory and of two trajectories that can be considered in the context of a first example of the use of the control method according to the invention. [Diagram 5] 5 is a graph plotted based on the graph of FIG. 4, showing the trends of different control torques of a motor vehicle. [Figure 6] FIG. 2 is a schematic representation of an obstacle, an obstacle avoidance trajectory and of two trajectories that can be considered in the context of a first example of the use of the control method according to the invention. [Figure 7] 7 is a graph plotted based on the graph of FIG. 6, showing the trends of different control torques of a motor vehicle. [Figure 8] FIG. 2 is a schematic representation of an obstacle, an obstacle avoidance trajectory and of two trajectories that can be considered in the context of a first example of the use of the control method according to the invention. [Figure 9] 9 is a graph plotted based on the graph of FIG. 8, showing the trends of different control torques of a motor vehicle. [Figure 10] FIG. 2 is a schematic representation of an obstacle, an obstacle avoidance trajectory and of two trajectories that can be considered in the context of a first example of the use of the control method according to the invention. [Figure 11] 11 is a graph plotted based on the graph of FIG. 10, showing the tendency of different control torques of a motor vehicle. [Figure 12] FIG. 2 is a schematic representation of an obstacle, an obstacle avoidance trajectory and of two trajectories that can be considered in the context of a first example of the use of the control method according to the invention. [Figure 13] 13 is a graph plotted based on the graph of FIG. 12, showing the trends of different control torques of a motor vehicle. [Figure 14] FIG. 2 is a schematic representation of an obstacle, an obstacle avoidance trajectory and of two trajectories that can be considered in the context of a first example of the use of the control method according to the invention. [Figure 15] 15 is a graph plotted based on the graph of FIG. 14, showing the trends of different control torques of a motor vehicle. [Figure 16] 11 is a graph illustrating an example of the variation of the steering angle setpoint as a function of time. [Figure 17] 17 is a graph plotted on the basis of the graph of FIG. 16 illustrating the activation and deactivation times of the control system of the vehicle of FIG. 1 in the context of a control method according to the invention. [Figure 18] 17 is a graph plotted on the basis of the graph of FIG. 16, illustrating the variation of the parameters K1 and K1rt used in the context of the method according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] 1 shows a motor vehicle 10 travelling on a road. In the examples which follow, a case will be considered in which the law requires that the vehicle be driven in the right hand lane, however, the invention could equally well be applied symmetrically to cases of driving on the left (as is the case in the UK for example).

[0023] 1, a motor vehicle 10 conventionally includes a chassis that defines a vehicle interior, two front drive wheels 11, and two rear non-drive wheels 12. Alternatively, these two rear wheels may also be drive wheels.

[0024] The motor vehicle 10 includes a conventional steering system 18 making it possible to influence the orientation of the front wheels 11 so as to be able to turn the vehicle. In the example considered, the steering system 18 is controlled by an assisted steering actuator 15 making it possible to influence the orientation of the front wheels 11 as a function of the orientation of the steering wheels 16 and / or, depending on the case, as a function of a set point issued by the computer 13.

[0025] In addition, it would be possible to provide the motor vehicle with a differential braking system making it possible to act differently on the speed of rotation of the front wheels 11 (or even on the speed of rotation of the rear wheels 12) so as to slow down the motor vehicle by turning it. This differential braking system would for example comprise controlled differential or electric motors arranged on the wheels of the vehicle.

[0026] Hereinafter, in this description, the steering system considered will be formed just by a conventional steering system. As a variant, the steering system can be formed by a combination of a conventional steering system and of a differential braking system.

[0027] A computer 13 is arranged to control the actuator 15. To this end, the computer 13 comprises at least one processor, at least one memory and different input and output interfaces.

[0028] Thanks to its input interfaces, the computer 13 is adapted to receive input signals emanating from various sensors.

[0029] Among these sensors the following are provided, for example: - a device such as a front-mounted camera that makes it possible to mark the position of the vehicle relative to the traffic lane; a device, such as a radar or lidar remote sensor, making it possible to detect an obstacle 100 (FIG. 3) located on the trajectory of the motor vehicle 10; - at least one side-mounted device, such as a radar or lidar remote sensor, making it possible to observe the environment to the side of the vehicle; a device, such as a gyrometer, that makes it possible to determine the speed of yaw rotation (around the vertical axis) of the motor vehicle 10, as well as - A sensor of the force exerted on the steering wheel and / or a steering wheel angular position sensor.

[0030] By virtue of its output interface, the computer 13 is adapted to transmit set points to the assisted steering actuator 15 .

[0031] The computer 13 thus makes it possible to ensure that the vehicle follows the reference trajectory formed in the example illustrated in FIG. 3 by the obstacle 100 avoidance trajectory T0, best and if the conditions justify doing so.

[0032] By virtue of its memory, the computer 13 stores data used in the context of the methods described herein below.

[0033] The computer 13 stores in particular a computer application consisting of a computer program containing instructions, the execution of which by the processor enables the computer to carry out the methods described herein below.

[0034] The computer 13, among other things, processes two computer applications: the avoidance trajectory T0 to be followed and, of course, the steering angle set point δ that enables the motor vehicle 10 to follow the avoidance trajectory T0. cand the above-mentioned steering angle set point δ c and a second application, hereinafter referred to as "EPS system 21", which enables determining the set point to be sent to the assisted steering actuator 15, taking into account the intention expressed by the driver.

[0035] The intention expressed by the driver is here inferred from the torque he applies to the steering wheel 16, which will be referred to hereinafter as the "steering wheel torque Cc". Alternatively, the intention can be inferred as a combination of this steering wheel torque and other factors, such as for example the angular position of the steering wheel.

[0036] Before describing these two systems, AES and EPS, in detail, various variables may be introduced that will be used in the context of the control methods described herein below, and some of which are illustrated in FIG.

[0037] The steering angle that the front drive wheels make with the longitudinal axis A1 of the motor vehicle 10 will be represented as "δ" and will be expressed in radians.

[0038] The lateral deviation between the longitudinal axis A1 of the motor vehicle 10 (passing through the center of gravity CG) and the avoidance trajectory T0 at the aiming distance “ls”, located in front of the vehicle, is “y L " and expressed in meters.

[0039] The aiming distance "ls" mentioned above will be measured from the center of gravity CG and will be expressed in metres.

[0040] The speed of the motor vehicle on the longitudinal axis A1 will be represented as "V" and will be expressed in m / s.

[0041] Figure 2 shows the two systems mentioned above, AES 20 and EPS 21. The way in which these systems actually work can now be explained.

[0042] When the motor vehicle 10 travels on a road along an initial trajectory (not shown and substantially parallel to the road) and a potentially dangerous obstacle 100 is detected, the AES system is activated.

[0043] Potentially dangerous obstacles are fixed obstacles located on or close to the initial trajectory, or moving obstacles whose trajectory poses a risk of intersecting with the initial trajectory.

[0044] This system AES20 then receives as input parameters P1 that make it possible to characterize the attitude of the motor vehicle 10 in its environment. These parameters P1 can be, for example, the lateral displacement y of the motor vehicle 10 at the aiming distance ls. L , the heading direction of the motor vehicle 10 relative to the road, the yaw rate of the motor vehicle 10, and so on.

[0045] The system AES20 is further adapted to determine or receive from another computer an obstacle 100 avoidance trajectory T0, which is generated, for example, as a function of the above mentioned parameters P1 and of the characteristics of the obstacle 100 (dimensions, speed, etc.).

[0046] It can be seen in FIG. 3, and in all the examples that will be considered herein below, that this avoidance trajectory T0 is planned to avoid obstacle 100 on the left by avoiding protection limits 101 and 102, making it possible to avoid any collision with the obstacle.

[0047] The rectangular shaped first protection limit 101 has a shape that is a function of the shape of the obstacle 100 and of any measurement errors of the sensors the motor vehicle is equipped with. The first protection limit 101 has a position that takes into account the possible speeds of the obstacle 100.

[0048] The second protection limit 102 has dimensions chosen as a function of the safety margin it is desired to provide. Here, it has the shape of a circle, the centre of which is located at the corner of the first protection limit 101 which is located closest to the avoidance trajectory T0.

[0049] The manner in which the avoidance trajectory T0 is generated will not be described in detail here, as it is not the object of the present invention.

[0050] Given the parameters P1 and the avoidance trajectory T0, the AES system 20 determines a preliminary steering angle setpoint δ for the front wheels 11 of the vehicle that will best enable the vehicle to follow this avoidance trajectory T0. c can be determined.

[0051] As an input, this preliminary steering angle set point δ c The EPS system 21 receives the filtered steering angle setpoint δ, which is saturated in amplitude and in rate of variation, using a controller 22. s Determine.

[0052] In other words, the preliminary steering angle set point δ c is the preliminary steering angle set point δ c exceeds a predetermined threshold (in absolute value), an upper limit is imposed and the preliminary steering angle set point δ c is adjusted so that it cannot fluctuate faster than another predetermined limit.

[0053] These thresholds are selected so that motor vehicle 10 remains controllable by the driver at all times in the event of assuming sole control of the vehicle.

[0054] This filtered steering angle set point δ s and the instantaneous steering angle δ of the drive wheels 11 (measured by an angle sensor) is then used to determine a preliminary torque set point Ca, which would be equal to the filtered steering angle set point δ if the preliminary torque set point Ca were delivered directly to the assisted steering actuator 15. s This allows the steering of the wheels to be controlled accordingly.

[0055] This preliminary torque set point Ca is then calculated using the parameter K1 rt and the parameter K1 rt The calculation of the parameter K1 will be explained later in this specification. rt which makes it possible to obtain the intermediate torque setpoint Ci.

[0056] The deviation (up to the extent of the multiplication term) between this intermediate torque setpoint Ci and the steering wheel torque Cc makes it possible to obtain the final torque setpoint Cr delivered to the assisted steering actuator 15.

[0057] The present invention relates more specifically to the above-mentioned parameter K1 rt This is related to the calculation of

[0058] In the rest of this specification, the correction gain K1 rt This parameter, called "Deactivate AES system 20," is used to deactivate AES system 20 when conditions permit and the driver wishes to regain control of operation of motor vehicle 10.

[0059] To check whether the conditions allow this, provision is now made to determine the area of ​​the environment of the obstacle 100 in which the motor vehicle 10 is located.

[0060] How to correct this gain K1 rt Before detailing how is calculated, the area of ​​the environment that will be considered to perform these calculations can be detailed.

[0061] As shown in figure 3, four zones of the environment are preferentially distinguished. As a variant, it would be possible to consider a smaller number (at least 2) or a larger number and to delimit these zones differently.

[0062] Here, these four zones are defined for the avoidance trajectory T0, for the obstacle 100 and for the protection line L1 beyond which any collision with the obstacle 100 is avoided.

[0063] This protection line L1 corresponds more specifically to an imaginary line that is parallel to the road (here, the protection line L1 is straight, but the protection line L1 may be curved if the road is curved) and passes through point P1 of the second protection limit 102 that is farthest from the obstacle 100.

[0064] The crossing of this line by the motor vehicle 10 (and more specifically by the center of gravity CG of said motor vehicle 10) makes it possible to ensure that the obstacle 100 is successfully avoided.

[0065] Four regions are defined as follows:

[0066] The first zone Z1 is located between the avoidance trajectory T0 and the protection line L1, upstream of the obstacle (more specifically, here, upstream of the first protection limit 101).

[0067] In this first zone Z1, the driver's intention is assumed to be close to the setpoint calculated by the AES system 20 so that there is no desire to be able to suspend operation of the AES system for safety reasons.

[0068] The second zone Z2 is located between the avoidance trajectory T0 and the protection line L1, alongside the obstacle and downstream of the obstacle (more specifically, here, alongside the first protection limit 101 and downstream of the first protection limit 101).

[0069] Since this area is located behind the obstacle 100 and therefore no longer poses any danger, it is now desirable to allow the driver the possibility of regaining full control of the vehicle, as long as he has both hands on the steering wheel.

[0070] The third zone Z3 is located on the other side of the reference trajectory T0 with respect to the first zone Z1, upstream of the obstacle 100 (more specifically, here upstream of the first protection limit 101).

[0071] In this area, the desire is to allow the driver the possibility of regaining control of driving the vehicle if the driver persists in defying the AES system 20 .

[0072] A fourth zone Z4 covers the remainder of the environment.

[0073] In this fourth region, the desire is to allow the driver the possibility of regaining control of operation of the vehicle if the driver opposes the AES system 20. Thus, in the fourth region, the AES requests are suspended as soon as the driver opposes, but gently, a maneuver commanded by the AES system.

[0074] Correction gain K1 rtTo calculate , computer 13 determines in which of these four zones motor vehicle 10 is located, and then computer 13 uses a non-identical calculation algorithm for each zone.

[0075] When the motor vehicle 10 changes zones, the computer does not immediately change the calculation algorithm so as not to create instabilities, but only when the vehicle then travels beyond a so-called hysteresis trajectory, which is calculated as a function of the avoidance trajectory T0.

[0076] In FIG. 3, two hysteresis trajectories T01, T02 are represented that follow the avoidance trajectory T0 at a predetermined fixed distance, for example 1 meter, to the right or to the left of the avoidance trajectory T0.

[0077] When the motor vehicle 10 goes from zone Z1 to zone Z3 (or vice versa) or from zone Z2 to zone Z4 (or vice versa), the computer changes the calculation algorithm only after the vehicle has traversed not only the avoidance trajectory T0, but also these two hysteresis trajectories T01, T02, which makes it possible, among other things, to avoid the phenomenon of oscillation between the zones.

[0078] Correction gain K1 rt The way in which is calculated can now be explained in detail.

[0079] This correction gain K1 rt The value of is derived from the value of gain K1, which is a Boolean value, which is determined as follows.

[0080] If the motor vehicle is located within a first zone Z1, this gain K1 is set equal to 1, which means that there is no desire to interrupt the AES system 20.

[0081] If the motor vehicle is located within the second zone Z2, the driver has both hands on the steering wheel, and the steering wheel torque Cc is above the first threshold value Cc2 in absolute value, the gain K1 is set equal to 0, which means that there is a desire to shut down the AES system 20.

[0082] In any other situation in the second zone Z2, the gain K1 is set equal to one.

[0083] If the motor vehicle is located within the third zone Z3 and the driver intends to avoid the obstacle to the right (contrary to AES system 20) while remaining within zone Z3, i.e., by shifting minimally about obstacle 100, gain K1 is set equal to 0, which means that there is a desire to interrupt AES system 20.

[0084] In order for the computer 13 to take into account that the driver intends to avoid an obstacle to the right by shifting minimally, the computer 13 determines whether the steering wheel torque Cc is negative and whether the steering wheel torque Cc exceeds a negative threshold Cc 3min (e.g. -2Nm)

[0085] Reflecting this, when the motor vehicle is located in the third zone Z3 and the driver is within the threshold Cc 3max If one intends to avoid an obstacle on the left (contrary to the AES system 20) by applying a steering wheel torque CC above (e.g., 2 Nm) and the AES system generates a negative torque, the gain K1 is further set equal to 0, which means that there is a desire to shut off the AES system 20.

[0086] In any other situation in the third zone Z3, the gain K1 is set equal to 1, meaning that there is a desire to maintain the AES system 20.

[0087] The motor vehicle is located in a fourth zone Z4, the driver is negative, and the threshold Cc 4min The threshold value Cc 4min The threshold Cc itself is negative (e.g., -3 Nm). 4min If the driver wishes to return to his initial lane, or at least counter the lateral velocity of the motor vehicle 10, by imposing a steering wheel torque Cc that is lower than the initial lane, and the AES system generates a positive torque, gain K1 is set equal to 0.

[0088] When the motor vehicle is located in the fourth zone Z4 and the driver exceeds the threshold value Cc 4max The threshold value Cc 4max The threshold Cc itself is positive (e.g., 3 Nm). 4max If one wishes to change lanes by continuing to move as far away from the obstacle 100 as possible by imposing a higher, positive steering torque Cc, the AES system will generate a negative torque, and the gain K1 is set equal to 0.

[0089] In any other situation in the fourth zone Z4, the gain K1 is set equal to one.

[0090] It will be noted that in the case where the gain K1 is equal to 0 and at least one of the conditions stated above is no longer satisfied, the gain K1 is immediately set to 1 again.

[0091] The computer 13 then calculates a correction gain K1, which here is a real number between 0 and 1 and which varies continuously. rt can be calculated.

[0092] This correction gain K1 rt is determined to avoid any abrupt corrections in the control of motor vehicle 10.

[0093] In other words, the correction gain K1 rtThe rate of change of is 0 (the correction gain K1 rt is equal to 0 or 1), otherwise it is constant and equal to a predetermined rate. Thus, as FIG. 18 shows, if the gain K1 exhibits a variation in the shape of a rectangular pulse, the correction gain K1 rt exhibits variations in the shape of trapezoidal pulses whose rising and falling edges are not vertical but oblique in the shape of a ramp.

[0094] Provision can be made for the rate of change for a rising edge to be greater than the rate of change exhibited for a falling edge. Each rising edge will begin when the gain K1 changes from 0 to 1, and each falling edge will be triggered when the gain K1 changes from 1 to 0.

[0095] The rate of change for each rising or falling edge is determined by the vehicle's lateral acceleration (e.g., 1 m.s -2 is determined as a function of the vehicle speed V and the radius of curvature of the road so as not to exceed a threshold value (V=1 / 2).

[0096] The gradient used will therefore be correspondingly lower when the speed V is high and correspondingly higher when the radius of curvature of the road is large. A mapping could be used that makes it possible to determine the gradient to be used.

[0097] Correction gain K1 rt Once obtained, the correction gain K1 rt is multiplied by the preliminary torque setpoint Ca.

[0098] This correction gain K1 rt When is equal to 1, which means that the AES system 20 is operational, the preliminary torque setpoint Ca is not modified and the assisted steering actuator 15 is controlled by the AES system 20 only.

[0099] Correction gain K1 rt When is equal to 0, which means that the operation of the AES system 20 must be suspended, the preliminary torque setpoint Ca is cancelled and the assisted steering actuator 15 is controlled only by the steering wheels 16.

[0100] Correction gain K1 between 0 and 1 rt Variation of θ enables a gradual and gentle transition from one mode of operation to the other, avoiding threshold effects.

[0101] In FIG. 2, two signals SA, SB corresponding to the reset signal are represented.

[0102] These two reset signals SA, SB are, among other things, connected to the correction gain K1 rt When changes from 0 to a non-zero value, the preliminary torque setpoint Ca calculation is reset to 0 and the measured steering angle value δ is filtered to the steering angle setpoint δ s Allows you to assign

[0103] The usefulness of these two signals will become clear and evident hereinafter in the present discussion with reference to FIGS.

[0104] Some specific examples illustrating the benefits of the present invention can now be described.

[0105] The first particular case illustrated in Figures 4 and 5 corresponds to a situation in which, after a first obstacle 100 avoidance phase, the motor vehicle 10 enters into a second zone Z2 and the driver wants to return very quickly to his initial traffic lane.

[0106] In this situation, the driver turns the wheels to the right by applying a steering wheel torque Cc that is negative, which is illustrated in Figure 4 by curve C3.

[0107] In this situation, the AES system 20 calculates a positive torque (i.e., makes the vehicle go left) that makes it possible to steer the motor vehicle 10 onto the avoidance trajectory T0. This torque is illustrated in Figure 5 by the curve C1. The curve T1 illustrated in Figure 4 shows the trajectory that would be followed by the motor vehicle 10 if it were controlled without interrupting the operation of the AES system 20.

[0108] It is then understood that without the present invention, i.e. without this possibility of interrupting the AES system 20, the steering wheel torque and the torque generated by the AES system would be opposite, which would create an uncomfortable feeling for the driver.

[0109] Now, since the situation considered here is not dangerous, the situation does not impose a burden on the driver against his will.

[0110] Then, thanks to the present invention, the gain K1 is corrected by the gain K1 rt is chosen equal to 0 so that there will be a continuous transition from 1 to 0. The intermediate torque setpoint Ci will then be gradually decreased (see curve C2 in FIG. 5) until it is cancelled, which will allow the vehicle to return to the initial lane as the driver wishes (see trajectory T2 illustrated in FIG. 4).

[0111] A second separate case illustrated in FIGS. 6 and 7 corresponds to a situation in which a driver may wish to effect a greater avoidance than that planned by AES system 20, for example to change traffic lanes.

[0112] In this situation, after proceeding beyond obstacle 100, the driver continues to turn the steering wheel to the left by applying a steering wheel torque Cc that is positive. This steering wheel torque is illustrated in FIG. 6 by curve C6.

[0113] The AES system 20, for its part, calculates a negative torque (i.e., makes the vehicle go to the right) that makes it possible to steer the motor vehicle 10 onto the avoidance trajectory T0. This torque is illustrated in Figure 7 by the curve C4. The curve T4 illustrated in Figure 6 shows the trajectory that would be followed by the motor vehicle 10 if the motor vehicle 10 were controlled without interrupting the operation of the AES system 20.

[0114] It is then realized that without the present invention, the steering wheel torque and the torque generated by the AES system would be opposite, and since this situation is not dangerous, it does not impose a burden on the driver against his will.

[0115] Then, thanks to the present invention, the gain K1 is corrected by the gain K1 rt is chosen equal to 0 so that there will be a continuous transition from 1 to 0. The intermediate torque set point Ci will then be gradually increased (see curve C5 in FIG. 7) until it is cancelled, which will allow the vehicle to proceed on another traffic lane as the driver wishes (see trajectory T3 illustrated in FIG. 6).

[0116] A third separate case illustrated in Figures 8 and 9 corresponds to a situation in which a driver may wish to perform a larger avoidance than that planned by the AES system 20 and then wish to quickly return to his or her initial traffic lane.

[0117] At the beginning of the avoidance, the driver turns the steering wheel hard to the left, and then, as the vehicle enters the fourth zone Z4, the driver counteracts by applying a negative torque to the steering wheel, which is illustrated in FIG.

[0118] From the start of the avoidance, the AES system 20 then calculates a negative torque (i.e., to make the vehicle go to the right) to steer the motor vehicle 10 onto the avoidance trajectory T0. This torque is illustrated in Figure 9 by curve C7. Curve T6 illustrated in Figure 8 shows the trajectory that would be followed by the motor vehicle 10 if it were controlled without interrupting the operation of the AES system 20.

[0119] As long as the vehicle is within zone Z4 and it is considered undesirable to interrupt the operation of AES system 20, gain K1 is kept equal to one.

[0120] On the other hand, when the vehicle enters the second zone Z2 and the driver maintains his intention to return quickly to the initial traffic lane, a moment will come when the steering wheel torque Cc and the torque generated by the AES system are of opposite signs. This situation is not considered dangerous, so it does not impose a burden on the driver against his will.

[0121] Then, thanks to the present invention, the gain K1 is corrected by the gain K1 rt is chosen equal to 0 so that there will be a continuous transition from 1 to 0. The intermediate torque setpoint Ci imposed by the actuator 15 will then be gradually decreased (see curve C8 in FIG. 9) until the intermediate torque setpoint Ci is cancelled, which will allow the vehicle to return quickly to its initial traffic lane as the driver desires (see trajectory T5 illustrated in FIG. 8).

[0122] A fourth separate case illustrated in Figures 10 and 11 corresponds to a situation in which a driver wants to effect an avoidance of an obstacle 100 on the left, but the torque the driver applies to the steering wheels is not sufficient to effectively avoid the obstacle 100.

[0123] In this situation, the driver therefore exerts a steering torque Cc that is positive and high enough only when the driver detects an obstacle and then the driver relaxes this force too quickly. This steering torque is illustrated in Figure 11 by curve C11. Curve T8 illustrated in Figure 10 shows the trajectory that would be followed by the motor vehicle 10 if the motor vehicle 10 were controlled only by the driver.

[0124] In this situation, as long as motor vehicle 10 is upstream of obstacle 100, in zone Z3, AES system 20 calculates a positive torque (i.e., makes the vehicle go left) that enables motor vehicle 10 to steer onto avoidance trajectory T0. This torque is illustrated in FIG. 11 by curve C10.

[0125] This situation is therefore potentially dangerous, thereby making it imperative for the driver to go against his will and not discontinue operation of the AES system 20.

[0126] Then, thanks to the invention, the gain K1 is kept equal to 1 so that the steering wheel torque Cc has a reduced influence on the trajectory taken by the vehicle.

[0127] Curve T7 illustrated in FIG. 10 indicates the trajectory that will then be followed by motor vehicle 10.

[0128] A fifth separate case illustrated in Figures 12 and 13 corresponds to a situation in which the driver has accomplished a satisfactory avoidance of obstacle 100, but then does not want to veer too far from the initial lane that the driver was in in order to pass obstacle 100 at a reduced distance.

[0129] In this situation, the driver initially steers the wheels to the left by applying a steering wheel torque Cc that is positive, and then the driver steers the wheels to the right by applying a negative torque just before the motor vehicle 10 is aligned with the obstacle 100. This steering wheel torque is illustrated in FIG.

[0130] In this situation, the AES system 20 calculates a torque that is positive (i.e., causes the vehicle to go left) as long as the vehicle is upstream of the obstacle 100. This torque is illustrated in FIG. 13 by curve C12.

[0131] Curve T10 illustrated in FIG. 12 indicates the trajectory that would be followed by motor vehicle 10 if motor vehicle 10 were controlled without interrupting operation of AES system 20.

[0132] It is then understood that without the present invention, i.e., without the possibility of interrupting operation of the AES system 20, the steering wheel torque and the torque generated by the AES system would initially be of the same sign and then be opposite, which would create an uncomfortable feeling for the driver.

[0133] Because the situations considered here are not dangerous, the situations do not impose a burden on the driver against his will.

[0134] Then, thanks to the present invention, the gain K1 is initially kept equal to 1, and then the gain K1 decreases as the steering wheel torque Cc becomes negative and the threshold Cc 3min (-2Nm) is lower than the moment the correction gain K1 rtwill transition intermittently from 1 to 0. The intermediate torque set point Ci will then be gradually decreased (see curve C14 in FIG. 13) until it is cancelled, which will allow the vehicle to pass the obstacle 100 at a reduced distance (see trajectory T9 illustrated in FIG. 12) as the driver wishes.

[0135] The sixth separate case illustrated in FIGS. 14 and 15 corresponds to a situation where the driver wants to avoid the obstacle 100 to the right, whereas the avoidance trajectory T0 passes the obstacle 100 on the left.

[0136] In this situation, the driver turns the wheels to the right by applying a steering wheel torque Cc which, for the driver, is always negative and high, which is illustrated in Figure 15 by curve C17.

[0137] In this situation, the AES system 20 calculates a torque that is positive (i.e., causes the vehicle to go left), which is illustrated in FIG.

[0138] Curve T12 illustrated in Fig. 14 shows the trajectory that would be followed by the motor vehicle 10 if it were controlled without interrupting the operation of the AES system 20. It can be seen that the torque imposed by the driver is high enough to counter the torque imposed by the AES system. Nevertheless, the feeling remains very unpleasant for the driver.

[0139] In this situation, it is therefore desirable to be able to allow the driver to select the side on which he or she wishes to avoid the obstacle 100.

[0140] Then, thanks to the present invention, the gain K1 is corrected by the gain K1 rtwill transition continuously from 1 to 0. The final torque set point Cr imposed by the actuator 15 will then be gradually decreased (see curve C16 in FIG. 15) until the final torque set point Cr is cancelled, which will allow the vehicle to avoid the obstacle to the right (see trajectory T11 illustrated in FIG. 14) as the driver wishes.

[0141] In Figures 16 to 18 examples of parameter trends over time are presented that clearly illustrate the invention.

[0142] 17 it can be ascertained that thanks to signal S1 the AES system is activated at time t0 which corresponds to the moment of detection of an obstacle 100 on the initial trajectory of the motor vehicle 10, in the vicinity of said motor vehicle 10. Moreover, thanks to signal S2 it is to be ascertained that there is a desire to suspend operation of the AES system between times t2 and t4.

[0143] Figure 16 shows - Preliminary steering angle set point δ c of, - Saturated steering angle set point δ s of, and - measured steering angle δ Shows trends.

[0144] It can be ascertained that at the time t0 of the detection of an obstacle, the steering angle will need to be just higher than the currently measured steering angle.

[0145] Preliminary steering angle set point δ c Due to the controller saturating, the saturated steering angle set point δ s The rate of variation of remains constrained between times t0 and t1 so as not to create instability.

[0146] Between the times t1 and t2, the preliminary steering angle set point δ in terms of amplitude or rate of change c It is no longer necessary to saturate the saturated steering angle setpoint δ s is the preliminary steering angle set point δ c This is equivalent to:

[0147] At time t2, as shown in FIG. 18, gain K1 is set to 0 to suspend operation of AES system 20.

[0148] Correction gain K1 rt then decreases linearly to reach a value of 0 at time t3.

[0149] Preliminary steering angle set point δ c continues to increase while the saturated steering angle set point δ s will then be kept constant between instants t2 and t3 thanks to the reset signals SA, SB.

[0150] At time t3 and until time t4, the saturated steering angle set point δ s is then kept equal to the measured steering angle δ. In this approach, the intermediate torque setpoint Ci is kept equal to 0, which leaves the driver alone in control of the steering.

[0151] At time t4, as shown in FIG. 18, gain K1 is set to 1 to suspend the interruption of operation of AES system 20.

[0152] Correction gain K1 rt then increases linearly further to reach a value of 1.

[0153] At that time t4, thanks to the reset signals SA and SB, the preliminary steering angle set point δ cis then equal to the measured steering angle δ. The preliminary steering angle set point δ c then increases very rapidly.

[0154] Preliminary steering angle set point δ c Due to the controller saturating, the saturated steering angle set point δ s The rate of variation of remains constrained in this situation so as not to create instability.

[0155] The measured steering angle δ is saturated due to the torque still being applied by the driver to the steering wheel 16. s It can be seen in Fig. 16 that the trajectory does not follow correctly. In fact, the trajectory that is followed is the result of the combination of the driver torque and of the AES demands. If the driver actively exerts himself on the steering wheel, he then regains control.

[0156] The present invention is by no means limited to the embodiments described and represented, but those skilled in the art will be able to add any modifications to the present invention in accordance with the present invention.

[0157] It thus follows that the method can be applied to other types of domains where individual trajectories have to be followed, for example in aeronautics or in robotics.

Claims

1. A control method for autonomously controlling an actuator (15) of a control system (18) of an autonomous propulsion device (10), the method comprising: - determining a reference trajectory (T0); - determining the position of said device (10) relative to said reference trajectory (T0); - obtaining a parameter (Cc) related to the force exerted by the driver on the manual control means (16) of said control system (18); calculating, by a computer (13), the control settings (Cr) of said actuators (15); Including, said control setpoint (Cr) being calculated as a function of said parameter (Cc) and said position of said device (10) relative to said reference trajectory (T0); said device (10) being a motor vehicle suitable for driving on a road and including at least one driving wheel (11), said manual control means (16) being a steering wheel, said control system (18) enabling each driving wheel (11) to be steered, said parameter (Cc) being related to a torque (Cc) applied to said steering wheel by said driver of said motor vehicle, The reference trajectory (T0) is determined such that the device (10) avoids an obstacle (100), four zones of the environment of the device (10) are taken into account by the computer, the limits of which are associated with four different calculation algorithms, the limits of which depend on the position of the obstacle (100) and / or on the position of the reference trajectory (T0) relative to the obstacle (100), and the calculation of the control setpoint (Cr) is - determining the area in which the device (10) is located, and by using an algorithm to calculate the control setting (Cr) to be selected as a function of the area in which the device (10) is located; It is carried out, The four areas are: a zone (Z1) located upstream of said obstacle (100) between said reference trajectory (T0) and a protection line (L1), which is an imaginary line parallel to the road, and beyond which any collision with said obstacle (100) is avoided; a zone (Z2) located alongside and downstream of said obstacle (100), between said reference track (T0) and said protection line (L1); a zone (Z3) located upstream of said obstacle (100), on the opposite side of said reference trajectory (T0) from said protection line (L1), and a zone (Z4), a part of which is located upstream of the obstacle (100) on the opposite side of the reference trajectory (T0) from the protection line (L1), and another part of which is located downstream of the obstacle (100) alongside the obstacle (100) on the opposite side of the reference trajectory (T0) from the protection line (L1); That is, the method.

2. 2. The control method according to claim 1, further comprising: determining an indicator (K1), the value of which depends on the area in which the device (10) is located and on the parameter (Cc); generating preliminary control setting values ​​(Ca) of the actuators (15) making it possible to steer the device (10) onto the reference trajectory (T0); and correcting the preliminary control setting values ​​(Ca) as a function of the value of the indicator (K1).

3. The indicator (K1) is adapted to take only one or the other of two values, and a correction indicator (K1) is provided which fluctuates intermittently between the two values ​​as a function of the indicator (K1). ｒｔ ), and the preliminary control setpoint (Ca) is configured to determine the correction indicator (K1 ｒｔ 3. The control method according to claim 2, wherein the correction is performed by multiplying the value of

4. The device (10) is a motor vehicle suitable for driving on a road, and the correction indicator (K1 ｒｔ When the correction indicator (K1 ｒｔ 4. The method of claim 3, wherein a rate of variation of said at least one of said first and second speeds is determined as a function of a speed of said motor vehicle and a radius of curvature of said roadway such that lateral acceleration of said motor vehicle does not exceed a determined threshold.

5. The preliminary control set value (Ca) is the steering angle set value (δ ｃ 5. The method according to claim 2, wherein the steering angle setpoint is itself calculated as a function of the position of the device (10) relative to the reference trajectory (T0) and filtered by a controller satisfying a setpoint amplitude limit model and a setpoint variation limit model.

6. When the device (10) moves from a first area to a second area, the computer (13) determines whether the device is moving along a hysteresis trajectory (T0) that is determined as a function of the reference trajectory (T0). １ , T0 ２ 6. A method according to claim 1, further comprising continuing to use the algorithm associated with the first area unless the algorithm has progressed beyond a certain threshold.

7. An autonomous device (10) comprising at least one actuator adapted to influence the trajectory of the device (10) and a computer (13) for controlling said actuator, characterized in that said computer (13) is programmed to implement the method according to any one of claims 1 to 6.

Images