Anticipating module, associated device and method for controlling path in real time

Abstract

An anticipating module for a device for controlling, in real time, the path of a motor vehicle includes a sub-module for computing a turning command for compensating for the curvature of a bend in the lane of the vehicle and a variable-gain device that is connected to an output of the computing sub-module. The gain of the variable-gain device is connected to a controller to adjust the gain so as to decrease the lateral offset between the centre of gravity of the vehicle and the centre of the lane of the vehicle depending on the result of the comparison of components of a vector of current measurements of state variables of the device to one another and to a detection threshold, the output of the variable-gain device being the steering command for compensating for the curvature of the bend.

Claims

1. An anticipating module for a real-time path control device of a motor vehicle, the anticipating module comprising: computing sub-module circuitry configured to compute a steering command to offset a curvature of a bend in a lane of the vehicle, and a variable-gain device linked to an output of the computing sub-module circuitry, wherein the variable-gain device is linked to a controller configured to adjust a gain value so as to decrease a lateral deviation between a center of gravity of the vehicle and a center of the lane of the vehicle as a function of a result of a comparison of components of a vector of current measurements of state variables of the variable-gain device with one another and with a detection threshold, an output of the variable-gain device being the steering command to offset the curvature of the bend.

2. The anticipating module as claimed in claim 1, further comprising second computing sub-module circuitry linked to an output of the variable-gain device and configured to compute a measurement vector pseudo-calculated using a model of the vehicle.

3. The anticipating module as claimed in claim 2, wherein the model of the vehicle is a bicycle model.

4. A real-time path control device of a vehicle configured to offset a curvature of a bend in a lane of a vehicle, the real-time path control device comprising: an anticipating module that includes computing sub-module circuitry configured to compute a steering command to offset the curvature of the bend in the lane of the vehicle, and a variable-gain device linked to an output of the computing sub-module circuitry, the variable-gain device being linked to a controller configured to adjust a gain value so as to decrease a lateral deviation between a center of gravity of the vehicle and a center of the lane of the vehicle as a function of a result of a comparison of components of a vector of current measurements of state variables of the variable-gain device with one another and with a detection threshold; and observer circuitry configured to generate, in real time, an estimated straight-lane-follow state vector of the vehicle such as to produce the steering command to stabilize a path of the vehicle in relation to the straight lane, the observer circuitry being linked to the anticipating module.

5. A real-time path control method for a motor vehicle configured to offset a curvature of a bend in a lane of a vehicle, the method being performed by an anticipating module that includes computing sub-module circuitry configured to compute a steering command to offset the curvature of the bend in the lane of the vehicle, and a variable-gain device linked to an output of the computing sub-module circuitry, the variable-gain device being linked to a controller, the method comprising: adjusting, via the controller, a gain of the variable-gain device of the anticipating module when vehicle oversteer in relation to a nominal configuration is detected, in order to reduce a lateral deviation between a center of gravity of the vehicle and a center of the lane of the vehicle.

6. The real-time path control method as claimed in claim 5, further comprising: determining that the vehicle is oversteering in relation to the nominal configuration, when the lateral deviation and a direction of the bend are oriented in a same direction in a reference frame of the vehicle and the lateral deviation is greater than a detection threshold.

7. The real-time path control method as claimed in claim 6, further comprising: resetting the gain of the variable-gain device, when the lateral deviation and the direction of the bend are oriented in different directions in the reference frame of the vehicle and the lateral deviation is less than a detection threshold.

Description

(1) Other objectives, characteristics and advantages of the invention are set out in the description below, given purely by way of non-limiting example and in reference to the attached drawings, in which:

(2) FIG. 1, as previously mentioned, is a schematic view of a real-time path control device for a vehicle according to the prior art,

(3) FIG. 2

(4) FIG. 3, as previously mentioned, show the evolution of the steering angle and the lateral deviation over time following the action of the control device according to the prior art when the parameters of the vehicle are at the nominal value and the trunk is empty,

(5) FIG. 4

(6) FIG. 5 show the evolution of the steering angle and the lateral deviation over time following the action of the control device according to the prior art when there is an additional mass in the trunk of the vehicle,

(7) FIG. 6 is a schematic view of an embodiment of a real-time path control device of a vehicle according to the invention,

(8) FIG. 7 shows an embodiment of the anticipating module according to the invention,

(9) FIG. 8 is a schematic view of a vehicle traveling in a lane with a bend,

(10) FIG. 9 shows an implementation method of a real-time path control device of a vehicle according to the invention, and

(11) FIG. 10

(12) FIG. 11 show the evolution of the steering angle and the lateral deviation over time following the action of the control device according to the invention when there is an additional mass in the trunk of the vehicle.

(13) FIG. 6 is a schematic view of a real-time path control device 5 of the vehicle 1 to offset the curvature of a bend in the lane of the vehicle 1 according to one aspect of the invention. The elements of the device 5 that are identical to the elements making up the device DISP in FIG. 1 are indicated using the same reference signs.

(14) The vehicle 1, the controller device 2 for generating a control signal Ust and the observer 3 for generating, in real time, the estimated straight-lane-follow state vector {circumflex over (ξ)} of the vehicle from the vector η of current measurements and the pseudo-calculated measurement vector η.sub.eq are shown.

(15) The device 5 also includes an anticipating module 6 having a first input 61 linked to the vehicle 1 and receiving the vector η of current measurements, a second input 62 linked to the vehicle 1 and receiving the polynomial y(x), a first output 63 linked to the adder such that the control signal U is the sum of the control signal Ust and the control signal Ueff generated by the module 6 and a second output 64 linked to the third input of the observer 3.

(16) The anticipating module 6 is an open loop.

(17) FIG. 7 shows an embodiment of the anticipating module 6.

(18) The anticipating module 6 includes the first sub-module for determining the curvature γff from the polynomial y(x) giving the geometry of the guide line of the traffic lane for each point at the distance x in front of the vehicle 1 determined by the RaCam device and linked to the input 62 of the module 6, a computing sub-module for computing a steering command 65 including a first input 66 linked to the output of the sub-module 41, a second input 67 linked to the input 61 of the module 6 and an output 68 linked to the input 69 of a variable-gain device 70.

(19) The variable-gain device 70 has a control input 71 linked to an output 72 of a controller 73.

(20) The controller 73 also has an input 74 linked to the input 61 of the module 6.

(21) The variable-gain device 70 has an output 75 linked firstly to the first output 63 of the module 6, and secondly to a first input 76 of a second computing sub-module 77.

(22) The second computing sub-module 77 also has a second input 78 linked to the first input 61 of the module 6 and an output 79 linked to the second output 64 of the module 6.

(23) The computing sub-module for computing a steering command 65 calculates a steering command to offset the curvature γff.

(24) The steering command is equal to the wheel angle δ.sub.cq given by the equation (7) and implemented by the computing sub-module for computing a steering command 65.

(25) The controller 73 controls the gain variable-gain device 70 so as to decrease the lateral deviation yl between the center of gravity of the vehicle 1 and the center of the lane of the vehicle depending on the result of the comparison of components of the vector η of current measurements of state variables of the device to one another and to a detection threshold S.

(26) The second sub-module 77 determines the pseudo-calculated measurement vector η.sub.eq according to the equation (8).

(27) In a variant, the first curvature determination sub-module 41 can be arranged outside the anticipating module 6.

(28) FIG. 8 shows the vehicle 1 traveling in a lane 80 with the bend of curvature γff.

(29) The vehicle 1 has a reference frame R, the origin of which for example coincides with the nominal center of gravity of the vehicle 1.

(30) The path of the vehicle 1 follows a central guide line 81 of the lane 80.

(31) At instant t1, the vehicle 1 is on a straight portion of the lane 80. The front wheels 82 and rear wheels 83 of the vehicle 1 are aligned, and the lateral deviation yl and the wheel angle δ are substantially zero.

(32) At instant t2, the vehicle 1 is on the bend.

(33) The device 5 reads a non-zero lateral deviation y12 between the nominal center of gravity of the vehicle 1 and the central guide line 81 of the lane 80, and generates a steering command Ust to offset the deviation between the set-point state vector ξ* and the estimated state vector {circumflex over (ξ)} such that the deviation is eliminated or moved towards zero.

(34) The sign of the wheel angle δ.sub.2 enables the direction of orientation of the bend to be determined.

(35) FIG. 9 shows an implementation method for the device 5.

(36) During the step 80, the controller 73 determines whether the vehicle 1 is oversteering on the bend.

(37) The vehicle 1 is deemed to be oversteering in relation to the nominal if the lateral deviation yl and the direction of the bend are oriented in the same direction in the reference frame R of the vehicle 1, and the value of the lateral deviation yl is greater than a detection threshold S.

(38) In the reference frame R of the vehicle 1 shown in FIG. 8, the oriented angle δ.sub.2 and the lateral deviation y12 are positive.

(39) Consequently, the lateral deviation y12 and the direction of the bend are oriented in the same direction.

(40) It is therefore assumed that the lateral deviation y12 is greater than the detection threshold S.

(41) The method advances to step 81.

(42) If either one of the two conditions are not met, the method remains in step 80.

(43) During step 81, the controller 73 sets the gain of the variable-gain device 70 to a predetermined value.

(44) During this step, the gain of the variable-gain device changes from 1 to the predetermined value, for example 0.75.

(45) The predetermined value is for example determined by testing the behavior of the vehicle 1 empirically or by digital simulation for different predetermined values.

(46) Adjusting the gain reduces the value yl of the lateral deviation between the center of gravity of the vehicle 1 and the center of the lane of the vehicle, as shown in FIGS. 10 and 11, which show the evolution of the steering angle δ and the lateral deviation yl over time following the action of the device 5, the trunk of the vehicle containing an additional 300 kg mass.

(47) The lateral deviation y1 is reduced to 20 cm.

(48) Furthermore, during the step 81, the controller 73 determines whether the vehicle 1 is still oversteering on the bend in relation to nominal.

(49) In a step 82, if the lateral deviation yl and the direction of the bend are oriented in different directions in the reference frame R of the vehicle 1 and the lateral deviation yl is less than the detection threshold S, the controller 73 resets the gain of the variable-gain device 70.