FR3075713A1 - DEVICE FOR CORRECTING THE PLATFORM OF A LIDAR OF A MOTOR VEHICLE - Google Patents

Abstract

Automatic attitude correction system for LIDAR of a motor vehicle and particularly autonomous motor vehicle consisting of a base comprising a cup in which is fixed the LIDAR, an attachment plate for holding the device on the roof of the vehicle and 'a setting cross. The latter allows, via a first pivot connection with the base, a pitch adjustment and, via a second pivot connection with the attachment plate, a roll adjustment. The invention also relates to the servo-control of this device. The attitude correction system is then coupled to two servomotors for controlling the two pivot links. The angular positioning errors in roll and pitch are sensed by an inertial matrix integral with the base and then are processed by a computer. The roll and pitch instructions are then sent from the computer to the two servomotors which then correct the attitude of the LIDAR by acting on the adjusting screws. According to a non-servo embodiment, a locking system in position, distinct from the adjustment system, makes it possible to avoid any inadvertent adjustment during use. The invention thus makes it possible to maintain the horizontal LIDAR in order to ensure optimal operation.

Description

Device for correcting the attitude of a LIDAR of a motor vehicle The invention relates to a device for holding an object, particularly suitable for maintaining a LIDAR on a motor vehicle. The invention also relates to a system for correcting the attitude of an object mounted on a motor vehicle. Finally, the invention relates to a motor vehicle as such.

A state-of-the-art autonomous motor vehicle generally comprises a sensor called "LIDAR" derived from the acronym of the English expression "laser detection and ranging". The LIDAR requires a horizontal position to function optimally. By way of example, document EP2786175 discloses a positioning solution for a LIDAR intended for measuring the wind speed. Such a solution does not prevent permanent oscillations of the LIDAR around its equilibrium position as defined.

During the use of an autonomous motor vehicle, the attitude of the motor vehicle varies depending on the load loaded, in particular related to the number of passengers. In addition, the LIDAR is generally fixed on the roof or roof of the motor vehicle, and is subject to mounting dispersions of its support. In addition, the trim of the LIDAR may be different from the initial setting at the factory. A control system with a short response time and a suitable corrector can also make it possible to compensate for the angular position deviations induced by the defects of the roadway (potholes for example), the roll induced by the cant of the road or the pitch induced by the donkeys, steps or other types of elevation caused by a particular development of the roadway.

Such a situation induces unacceptable inaccuracies with prior art solutions, since the data measured by LIDAR can have consequences for the safety of the occupants of the motor vehicle.

The object of the invention is to provide a device which overcomes the above drawbacks.

More specifically, the invention provides a solution for reliably correcting the attitude of a LIDAR attached to a motor vehicle. To this end, the invention is based on a device intended to hold an object, in particular an object of the LIDAR detector type, in a plane, in particular a horizontal plane, characterized in that it comprises: a base intended to support the object , a device fixing plate, in particular a device fixing plate intended to be fixed on a motor vehicle, an adjustment cross disposed between the fixing plate and the base, the adjustment cross being linked to the base by a first pivot link, and linked to the fixing plate by a second pivot link with an axis substantially perpendicular to the axis of the first pivot link, and characterized in that the device comprises: a first means for adjusting the rotation of the first pivot link, a second means for adjusting the rotation of the second pivot link.

The first adjustment means may comprise a first screw cooperating with a first tapping so as to move the base relative to the adjustment cross around the first pivot link, and / or the second adjustment means may comprise a second cooperating screw with a second thread so as to move the fixing plate with respect to the adjustment cross around the second pivot link.

The screwing of the first screw can generate a rotation in one direction, the unscrewing of the first screw generating a rotation in an opposite direction, and / or the screwing of the second screw can generate a rotation in one direction, the unscrewing of the second screw generating a rotation in an opposite direction.

The device may comprise: a first means for locking in position of the first pivot link, in particular a first means for locking in position provided with a first screw that can be actuated manually, and / or a second means for locking in position of the second pivot link , in particular a second position locking means provided with a second screw that can be actuated manually.

The first means for adjusting the rotation of the first pivot link can comprise a first control means, and / or the second means for adjusting the rotation of the second pivot link can comprise a second control means. The invention also relates to a trim correction system comprising a device as described above so as to place an object, in particular an object of the LIDAR detector type, in a horizontal plane, characterized in that it comprises a computer, an inertial matrix connected by a first communication device to the computer, the inertial matrix measuring roll and pitch angles of the base of the device, and the computer calculating attitude corrections as a function of measurements of the inertial matrix, and may include a second communication device from the computer to control means so as to transmit to them instructions for correcting the attitude of the base.

The computer can belong to an electronic card fixed to the fixing plate and the inertial matrix can be fixed to the base. The invention also relates to a motor vehicle, characterized in that it comprises a device as described above, and / or a trim correction system as described above.

The first pivot link of the device can be of axis parallel to the transverse direction of the motor vehicle, and the second pivot link of the device can be of axis parallel to the longitudinal direction of the motor vehicle.

The accompanying figures show, by way of example, two embodiments of the invention, a first basic mode without automatic control and a second advanced mode with motorized control.

Figure 1 is a schematic view of a motor vehicle according to the first basic embodiment of the invention, without automatic control.

Figure 2 is an exploded view of a device according to this first embodiment of the invention.

Figure 3 is a perspective view of the device according to this first embodiment of the invention.

Figure 4 is another perspective view of the device according to this first embodiment of the invention.

FIG. 5 is a detailed view of adjustment means according to this first embodiment of the invention.

FIG. 6 is a diagram illustrating the operation of a device according to a second advanced embodiment of the invention, with motorized servoing.

Figures 7 and 8 are block diagrams illustrating the servo-control of the device according to this second embodiment of the invention.

FIG. 9 is a partial schematic view of the device according to any one of the two embodiments of the invention, illustrating the relationship between the translation generated by the adjustment threaded rod, motorized or not, and the roll angle / pitch thus generated at the LIDAR.

Figure 10 is a schematic sectional view, along a vertical and transverse plane, of the device according to the second embodiment of the invention.

Figure 11 is a schematic sectional view, along a vertical and longitudinal plane, of the device according to the second embodiment of the invention.

FIG. 12 is a detailed perspective view of an anti-blocking adjustment means of the device according to the second embodiment of the invention.

The direction in which a motor vehicle usually travels in a straight line is defined as the longitudinal direction X ’. By convention, the direction perpendicular to the longitudinal direction X ’, located in a plane parallel to the ground, is called transverse direction Y’. The third direction, perpendicular to the other two, is called the vertical direction Z ’.

Thus, a horizontal plane is a plane defined by the longitudinal X 'and transverse Y' directions.

According to an embodiment illustrated in FIG. 1, a motor vehicle 1, for example autonomous, comprises a device 10 supporting a LIDAR type detector or sensor 5. The device 10 is preferably fixed on the roof 2 of the motor vehicle 1.

As illustrated in FIGS. 2, 3 and 4, the device 10 comprises a base 20, provided with a cup 21 preferably circular, intended to support the LIDAR 5. The device 10 also comprises a fixing plate 60 intended to be fixed on the motor vehicle 1. The fixing plate 60 can for example be fixed to a mast, via a fixing tube 61, or also to at least one roof bar, for example by means of a clamp system (not represented).

The device 10 also comprises an adjustment cross 40 arranged between the fixing plate 60 and the base 20. The adjustment cross 40 is linked on the one hand to the base 20 by a first pivot link 30 of axis Y. It is also linked to the fixing plate 60 by a second pivot link 50 of axis X. Preferably the two axes X and Y of the two pivot links are perpendicular and positioned in the same plane.

As illustrated in FIG. 2, the base 20 comprises four curved arches 22, 23, each having substantially a semi-circular shape. The tops of each hoop intersect substantially perpendicularly to the level of the cup 21. As a result, the base 20 comprises four legs, formed by the four hoops, in the form of a quarter of a circle, which extend downwards from the cup 21. These four legs are distributed uniformly around the cup, every 90 degrees. The two arches 23 participating in the pivot link 30, they will preferably be longer than the other two opposite first arches 22 having no similar function to perform.

The adjusting cross 40 comprises four hoops 41 each having a quarter-circle shape, connected at the same point by a first end, and extending downwards in a uniformly distributed manner, every 90 degrees. The four hoops 41 of this adjustment cross thus have a shape corresponding substantially to the hoops 22, 23 of the base 20, for their cooperation.

According to the embodiment of the invention, the axis X of the second pivot link 50 is positioned parallel to the longitudinal direction X 'of the motor vehicle 1, and the axis Y of the first pivot link 30 is positioned parallel to the transverse direction Y ′ of the motor vehicle 1.

As a result, the base 20 has an articulation relative to the fixing plate 60 along two perpendicular horizontal axes.

As illustrated more precisely in FIG. 5, the device 10 comprises a first means of adjusting 31 in rotation of the first pivot link 30 and a second means of adjusting 51 in rotation of the second pivot link 50. The first adjusting means 31 comprises a first screw or first threaded rod 32 cooperating with a first tapping 33 so as to move the base 20 relative to the adjustment cross 40 around the first pivot link 30. The second adjustment means 51 comprises a second screw or second threaded rod 52 cooperating with a second thread 53 so as to move the adjustment cross 40 relative to the fixing plate 60 around the second pivot connection 50.

The screwing of the first screw 32 generates a rotation in one direction, the unscrewing of the first screw 32 generating a rotation in an opposite direction. Thus, the first pivot link 30 can be adjusted in both directions by means of the first screw 32 and the first tapping 33. The screwing of the second screw 52 generates a rotation in one direction, the unscrewing of the second screw 52 generating rotation in an opposite direction. Thus, the second pivot link 50 can be adjusted in both directions by means of the second screw 52 and the second tapping 53. As illustrated in FIG. 5, the second tapping 53 is fixed to the fixing plate 60, the second screw 52 being in pivot connection with respect to the adjustment cross 40. As illustrated in FIG. 3, the first thread 33 is fixed to the adjustment cross 40, the first screw 32 being in pivot connection with respect to the base 20.

Alternatively, the second thread can be fixed to the adjustment cross 40, the second screw being in pivot connection relative to the fixing plate 60. The first thread can be fixed to the base 20, the first screw being in pivot connection by relative to the adjustment cross 40. These adjustment means may alternatively be different.

Preferably, as illustrated in FIG. 3, a first means for locking in position 34 or locking the first pivot link 30 is provided, for example by means of a first manually actuable screw 35. Preferably, a second means of blocking in position 54 or locking of the second pivot link 50 is provided, for example by means of a second screw that can be actuated manually 55. The first and second screws that can be actuated manually 35, 55 may be provided with “butterfly” heads giving them a easy screwing / unscrewing by hand, that is to say without requiring a key. It should be understood that these blocking means, as described in this first embodiment, are optional and must necessarily be unlocked or removed in the context of controlled operation, like the second embodiment which follows. The blocking function can be implemented differently.

The device 10 for supporting a LIDAR, described above, is advantageously integrated into an attitude correction system 80, at least automatic, which will be detailed below.

According to the embodiment, the attitude correction system 80, illustrated in FIG. 6, comprises a battery 3, for example the 12V battery supplying the general network of the motor vehicle 1, which supplies a transformer 4. The latter transforms the 12V voltage at a voltage lower than 5V, which supplies an electronic card 73. The electronic card 73 comprises for example a computer 70 and a data carrier 71. The electronic card 73 is preferably fixed to the fixing plate 60, for example in below, as illustrated in FIGS. 10 and 11 and shown diagrammatically in FIG. 6. The electronic card 73 is thus fixed relative to the motor vehicle 1. Advantageously, an inertial matrix 72, for example fixed on the base 20 as illustrated in FIG. 10, measurement of the roll angles (around the longitudinal axis X 'of the motor vehicle 1) and of pitching (around the transverse axis Y' of the vehicle a utomobile 1) and transmits them to the electronic card 73. This transmission of information between the inertial matrix 72 and the electronic card 73, or the computer 70 directly, is ensured by a first communication device which can be wired or preferably, wireless. The electronic card 73, in particular via the computer 70, then calculates the corrections to be made, via the first and second pivot connections 30, 50, respectively of axes Y, X. Once the calculations have been made, instructions for roll CR and pitch instructions CT depart from the electronic card 73 towards servo means 36, 56 so that the base 20 is brought back into a horizontal position if necessary, by acting on the two pivot links. This transmission of information between the electronic card 73, or the computer 70, and the servo means 36, 56 is provided by a second wired or wireless communication device.

The first and second control means 36, 56 are respectively fixed on the base 20 and on the adjustment cross 40. Each control means comprises for example a geared motor, or a servomotor, or a motor, preferably electric, their respective output shaft being adapted so as to drive the first and second screws 32, 52. Alternatively, each output shaft comprises a threaded part ensuring the role of screws 32, 52 for adjusting directly. These output shafts or screws 32, 52 cooperate, as seen above, with the threads 33, 53. In this embodiment, the blockages are not ensured by means of blocking in specific position, but by the servo means 36, 56 themselves, for example provided with mechanisms of type wheels and irreversible worms.

Thus, as illustrated in FIGS. 6 and 11, the first control means 36 generates the pitch settings RT on the first pivot link 30 of axis Y. As illustrated in FIGS. 6 and 10, the second control means 56 generates the roll settings RR on the second pivot link 50 of axis X.

As illustrated in FIGS. 7 and 8, the transfer functions of the servo means use the following equations:

Converter: U = - x σ 2π

PID corrector: Fc (p) = Kp p- ^] (1 + τάρ) (Transfer function of the corrector in the Laplace domain) {U = L - + RI + Κβω (electric equation) Μ άω

Kcl = J - + f mechanical adequacy)

kc

Sl (p) = U (p) x çLp + Ryjp + + KcKe (engine transfer function in the Laplace domain)

Integration: 0m (t) = f mm (t) dt 0m (p) = Ω (ρ) x - (integration function in the Laplace domain) Mechanism: 0m = χ p

Not

As illustrated in FIG. 9, for the screw-nut connection for adjusting the roll, we have the equation: Δχ = - x Δ0τη 2π and for the second pivot connection 50 of the device 10, we have the equation: Δχ = Rs x ΔΘ which gives _ 2nRs n 0m = -x 0

Pitch where Rs is the radius between the axis of rotation X for the adjustment and the axis of the corresponding servo means 56, and Pitch is the pitch of the screw thread 52.

Thus, the translation generated by the screw-nut connection is approximated by a portion of a circle of radius Rs.

Indeed, the rotation of the second screw 52 corresponds to an angular displacement of the adjustment cross 40 relative to the fixing plate 60 around the axis X (case of roll). The rotation of the first screw 32 corresponds to an angular displacement of the base 20 relative to the adjustment cross 40 along the axis Y (case of pitch).

Advantageously, as illustrated in FIG. 12, the nuts or threads 33, 53 each have two degrees of freedom, for example a rotation about an axis A and a translation along a perpendicular axis B, by means of a pivot link and a slide link 38, 58 (or: "by means of a complex link allowing rotation around an axis A and translation around a transverse axis B and of which FIG. 12 proposes a Such an arrangement makes it possible to avoid, if necessary, constraints, or even a blockage, of the device 10 during the adjustments.

Thus, the adjustment of the roll of the LIDAR 5, that is to say the inclination around the longitudinal direction X ′ of the motor vehicle 1, is carried out by the second screw 52 piloted between the fixing plate 60 and the cross 40. The adjustment of the pitch of the LIDAR 5, that is to say the inclination around the transverse direction Y ′ of the motor vehicle 1, is carried out by the first screw 32 driven between the adjustment cross 40 and the base 20. The base of the base 20, and consequently of the LIDAR 5 fixed on it, can then be corrected so that the LIDAR is continuously placed in a horizontal plane. The plate of the LIDAR 5 is easily corrected automatically thanks to the first pivot link 30 and the second pivot link 50, both of which are adjustable.

The device 10, by its “sphere-sphere” connection, allows simultaneous pitch and roll adjustment without blocking. The first pivot link 30 and the second pivot link 50 make it possible to increase the degree of hyperstatism and ensure good stability of the adjustment. In addition, the dissociation of the adjustment means 31, 51 and of the locking means in position 34, 54 makes it possible to limit the loosening during use and to compensate for untimely misadjustments of the device 10 in the first non-controlled embodiment. . Preferably, the surface conditions are deliberately degraded at the level of the contacts between the fixing plate 60 and the adjustment cross 40 and between the adjustment cross 40 and the base 20, in order to further limit any untimely loosening of the connections. .

Thanks to hoops arranged in a semi-sphere shape of the adjustment cross 40 and the base 20, and via the space-saving fixing plate 60, a space remains free under the LIDAR 5, which facilitates its attachment to its base 20 (this also facilitates the integration of the computer 73 which can then be installed in this area). The adjustment means 31, 51 of the screw-nut type allow the LIDAR to be held in position when the device 10 is released, while offering great adjustment precision. Finally, the adjustment means 31, 51 of the screw-nut type facilitate the installation of the servo-control means in position of the device 10 supporting the LIDAR 5.

Thus, the attitude correction system 80 comprising the device 10, equipped for example with two servomotors at each adjustment means 31, 51, coupled to at least one gyroscope or to an inertial matrix, makes it possible to drive in screwing / unscrewing each screw 32, 52 so as to correct the pitch and roll angles in real time. In other words, the correction of the attitude of the LIDAR 5 is ensured so that it remains horizontal, whatever the conditions of use of the motor vehicle 1. The LIDAR then performs optimal measurements.

In addition, the device 10 allows fine adjustment of the roll around the longitudinal direction X ′ and fine adjustment of the pitch around the transverse direction Y ′, while offering blockings in position once the adjustment (s) has been made. (s) in a non-slave embodiment.

The solution is particularly suitable for adjusting the attitude of a LIDAR mounted on an autonomous motor vehicle and has the following advantages: - It is compact; - It guarantees a precise, horizontal and stable position of a LIDAR on a motor vehicle. Note that this solution can be adapted to the attitude correction, possibly in real time, of another device than a LIDAR, for example of a camera mounted on a motor vehicle. In addition, it can be applied to other vehicles requiring a real-time attitude correction of a LIDAR, in other words stabilization or adjustment in horizontal position of their LIDAR, and / or of a camera, such such as trucks, boats, planes or helicopters. This solution can also be used on drones for the attitude correction of a LIDAR and / or a camera. Finally, this solution can find an application in the field of civil engineering, for example for the horizontal position adjustment of a 3D scanner. The invention thus relates more generally to a device for holding an object.

Claims (9)

claims 1. Device (10) intended to hold an object, in particular an object of the LIDAR detector type (5), in a plane, in particular a horizontal plane, characterized in that it comprises: a base (20) intended to support the object, a fixing plate (60) of the device (10), in particular a fixing plate (60) of the device (10) intended to be fixed on a motor vehicle (1), an adjustment cross (40) disposed between the fixing plate (60) and the base (20), the adjustment cross (40) being linked to the base (20) by a first pivot link (30), and linked to the fixing plate (60) by a second pivot link (50) with an axis substantially perpendicular to the axis of the first pivot link (30), and characterized in that the device (10) comprises: a first means (31) for adjusting the rotation of the first link pivot (30), a second means for adjusting (51) in rotation of the second pivot link (50). 2. Device (10) according to the preceding claim, characterized in that the first adjustment means (31) comprises a first screw (32) cooperating with a first thread (33) so as to move the base (20) relative to the adjustment cross (40) around the first pivot link (30), and / or in that the second adjustment means (51) comprises a second screw (52) cooperating with a second thread (53) so as to move the fixing plate (60) relative to the adjustment cross (40) around the second pivot link (50). 3. Device (10) according to the preceding claim, characterized in that the screwing of the first screw (32) generates a rotation in one direction, the unscrewing of the first screw (32) generating a rotation in an opposite direction, and / or in that the tightening of the second screw (52) generates a rotation in one direction, the unscrewing of the second screw (52) generating a rotation in an opposite direction. 4. Device (10) according to one of the preceding claims, characterized in that the device (10) comprises: a first locking means in position (34) of the first pivot link (30), in particular a first locking means in position (34) provided with a first screw that can be actuated manually (35), and / or a second means for locking in position (54) of the second pivot link (50), in particular a second means for locking in position (54) with a second manually actuated screw (55). 5. Device (10) according to one of claims 1 to 4, characterized in that the first adjustment means (31) in rotation of the first pivot link (30) comprises a first servo means (36), and / or in that the second adjustment means (51) in rotation of the second pivot link (50) comprises a second servo means (56). 6. attitude correction system (80) comprising a device (10) according to one of the preceding claims so as to place an object, in particular an object of the LIDAR detector type (5), in a horizontal plane, characterized in that that it comprises a computer (70), an inertial matrix (72) connected by a first communication device to the computer (70), the inertial matrix (72) measuring roll and pitch angles of the base (20) of the device (10), and the computer (70) calculating attitude corrections as a function of measurements of the inertial matrix (72), and in that it comprises a second device for communicating from the computer (70) to means servo (36, 56) so as to transmit to them instructions for correcting the attitude of the base (20). 7. attitude correction system (80) according to the preceding claim, characterized in that the computer (70) belongs to an electronic card (73) fixed to the fixing plate (60) and in that the inertial matrix (72 ) is fixed on the base (20). 8. Motor vehicle (1), characterized in that it comprises a device (10) according to one of claims 1 to 5, and / or a trim correction system (80) according to claim 6 or 7. 9. Motor vehicle (1) according to the preceding claim, characterized in that the first pivot link (30) of the device (10) is of axis (Y) parallel to the transverse direction (Y ') of the motor vehicle (1) , and in that the second pivot link (50) of the device (10) is of axis (X) parallel to the longitudinal direction (X ') of the motor vehicle (1).