Managing the operation of a head-up display system in a motor vehicle using an inertial measurement unit located at the front of the vehicle

Abstract

The invention relates to a method for managing the operation of a head-up display (2) in a motor vehicle (1) using an inertial measurement unit (3) arranged at the front of the vehicle's passenger compartment on the driver's side. The invention also relates to a computer device (100) implementing such a method, as well as a motor vehicle (1) comprising such a device (100). Figure for the abstract: 1

Description

Title of the invention: Management of the operation of a head-up display system in a motor vehicle using an inertial measurement unit located at the front of the vehicle. Technical field of the invention

[0001] The present invention relates to the field of head-up display systems for motor vehicles. The invention relates in particular to a method for managing the operation of a head-up display system in a motor vehicle. The invention also relates to a device implementing such a method, as well as a motor vehicle comprising such a device. The invention is applicable to motor vehicles such as motor vehicles, particularly cars. Prior art

[0002] Some modern motor vehicles are equipped with a head-up display that projects driving information onto the windshield, positioned so that it is within the driver's field of vision when they are looking forward. To ensure that this information is always optimally visible to the driver, some vehicles incorporate an inertial measurement unit (IMU) used by the head-up display to orient or stabilize the displayed information in response to vehicle movements. This is because the displayed information must remain precisely positioned within the driver's field of vision at all times, and this field of vision is influenced by vehicle movements.However, conventional vehicles typically integrate the inertial measurement unit (IMU) in a location relatively far from the head-up display (HUD), preferably near the vehicle's center of mass. This means that data generated by the IMU must be transmitted through the vehicle's communication networks and pass through several processors before it can be used by the HUD. This introduces latency, which can result in a lag between the positioning of the information displayed by the HUD and the vehicle's movements, potentially leading to a significant decrease in the visibility of the displayed information. Summary of the invention

[0003] The invention aims to solve this problem. In particular, it aims to provide a solution for improving the accuracy of the positioning of information displayed by a head-up display in a motor vehicle as a function of the vehicle's movements. In this way, the invention aims to enable the provision of more ergonomic and safer motor vehicles.

[0004] In order to achieve these goals, the invention relates, according to a first aspect, to a method for managing, by means of a computer device embedded in a motor vehicle, the operation of a head-up display system of the vehicle, the vehicle comprising an inertial measurement unit arranged at the front of the vehicle's passenger compartment on the driver's side, the method comprising the steps of: i. obtain data characterizing the moment of inertia of the vehicle with respect to at least one axis of a first Cartesian reference frame which are generated by the inertial measurement unit; ii. determine, based on the data obtained during step i), data characterizing the moment of inertia of the vehicle with respect to at least one axis of a second Cartesian frame of reference; and iii. manage the operation of the head-up display equipment based on the data determined during step ii).

[0005] According to one variant, step ii) can be carried out using at least one equation defined in accordance with the parallel axes theorem.

[0006] According to another variant, the origin of the second reference frame can be located at the center of mass of the vehicle.

[0007] According to a second aspect, the invention relates to a device for managing the operation of a head-up display device of a motor vehicle, the vehicle comprising an inertial measurement unit arranged at the front of the vehicle's passenger compartment on the driver's side, the device comprising at least one information processing unit, including at least one processor, and a data storage medium configured to implement a method as described above.

[0008] According to a third aspect, the invention relates to a computer program comprising program code instructions for the execution of the steps of a process as described above when said program is executed by at least one processor.

[0009] According to a fourth aspect, the invention relates to a medium usable in a computer on which a program as described above is recorded.

[0010] According to a fifth aspect, the invention relates to a motor vehicle comprising a head-up display system, an inertial measurement unit arranged at the front of the vehicle's passenger compartment on the driver's side and a device as described above.

[0011] According to one variant, the inertial measuring unit can be arranged at a distance from a driver's instrument cluster of between one and fifty centimeters.

[0012] According to another variant, the inertial measuring unit can be integrated into the instrument combination.

[0013] According to yet another variant, the inertial measuring unit can be arranged in a housing which integrates at least one optical component of the head-up display equipment. Brief description of the figures

[0014] Other features and advantages of the invention will become apparent from an examination of the detailed description below, and the accompanying figures, in which:

[0015] [Fig-1] is a diagram of a motor vehicle according to the invention;

[0016] [Fig.2] is a functional diagram of a device according to the invention; and

[0017] [Fig.3] is a flowchart of the steps of a process according to the invention. Detailed description of the invention

[0018] Figure 1 schematically illustrates a motor vehicle 1 according to the invention. This vehicle is equipped with a head-up display (HUD) 2, which conventionally displays visual content on the vehicle's windshield, positioned so as to be within the driver's field of vision when the driver is looking at the road ahead. The vehicle 1 according to the invention also includes an inertial measurement unit (IMU) 3, which measures the movements of the vehicle 1 using various sensors (e.g., accelerometer, gyroscope, etc.). According to the invention, the inertial measurement unit is advantageously located at the front of the vehicle 1's passenger compartment on the driver's side. For example, it is positioned at a distance of between one and fifty centimeters from the instrument cluster of the driver's seat. Alternatively, the inertial measurement unit 3 is integrated into the instrument cluster.According to the preferred embodiment, the inertial measurement unit 3 is arranged in a housing which integrates at least one optical component of the head-up display equipment 2.

[0019] Advantageously, the vehicle 1 according to the invention further incorporates a device 100 for managing the operation of a head-up display of a motor vehicle within the meaning of the present invention, as described below, which implements a method for managing the operation of a head-up display of a motor vehicle within the meaning of the present invention, as briefly summarized below and described in detail below.

[0020] During driving, the device 100 according to the invention acquires data generated by the inertial measurement unit 3 based on the vehicle's movements, in particular data characterizing the moment of inertia with respect to each axis of a Cartesian coordinate system, where the X-axis extends along the length of the vehicle 1, the Y-axis along the width of the vehicle 1, and the Z-axis along the height of the vehicle 1. This data is then processed to perform a change of reference frame due to the offset position of the inertial measurement unit 3. The processed data, which define the movements of the vehicle 1 in a new reference frame, are finally used to manage the operation of the head-up display 2.This is how the device 100 according to the invention makes it possible to minimize latency, thus allowing more precise positioning of the information displayed by the head-up display equipment 2 which more reactively follows the movements of the vehicle 1.

[0021] Figure 2 schematically illustrates the device 100 for managing the operation of a head-up display system in a motor vehicle according to the invention. It is essentially a computer device, which includes at least one information processing unit 101, comprising one or more processors, a data storage medium 102, on which is recorded, in particular, a program comprising program code instructions for executing the steps of the process according to the invention described below, and an input and output interface 103 enabling the reception and transmission of data.

[0022] Preferably, the device 100 according to the invention is hosted on an independent computer and interacts via its input and output interface 103 and by means of a wired vehicle communication network (e.g., CAN, Ethernet, MOST) – represented in [Fig. 1] by the double-headed arrows – with the head-up display unit 2 and with the inertial measurement unit 3. Alternatively, the device 100 according to the invention is partially or entirely part of the head-up display unit 2 or the inertial measurement unit 3. As a result, the device 100 according to the invention can, in particular, obtain data characterizing the moment of inertia of the vehicle with respect to at least one axis of a first Cartesian reference frame, which are generated by the inertial measurement unit 3, and it can also manage the operation of the head-up display unit 2.

[0023] According to the invention, all the elements described above contribute to enabling the implementation of a method for managing the operation of a head-up display device of a motor vehicle within the meaning of the present invention, as described below in relation to [Fig.3].

[0024] Figure 3 illustrates, by means of a flowchart, the steps of the process according to the invention.

[0025] According to a first step 301 of the method according to the invention, the device 100 according to the invention obtains data characterizing the moment of inertia of the vehicle with respect to at least one axis of a first Cartesian frame of reference, which are generated by the inertial measurement unit 3. In fact, the device 100 according to the invention acquires, during this first step, data characterizing the moment of inertia of the vehicle 1 with respect to each of the three axes of the Cartesian frame. Logically, the origin of the first Cartesian frame of reference is located at the position of the inertial measurement unit 3, and is therefore offset from the center (or center of mass) of the vehicle 1.In fact, the data acquired during this first step of the process cannot be used directly to manage the operation of the head-up display 3, because a discrepancy would then exist between the movements of vehicle 1 estimated using this data and the actual movements of vehicle 1. Indeed, due to the remote position of the inertial measurement unit 3, the rotation measurements around the axes (e.g., yaw, pitch, roll) are subject to a discrepancy.

[0026] Then, according to a second step 302 of the method according to the invention, the device 100 according to the invention determines, based on the data it has obtained during the previous step of the method, data characterizing the moment of inertia of the vehicle with respect to at least one axis of a second Cartesian reference frame, the origin of which is preferably located at the center of mass of the vehicle 1. To do this, the device 100 according to the invention uses equations defined in accordance with the parallel axes theorem.For example, with respect to the first X-axis, which extends along the length of the vehicle from rear to front, the device according to the invention solves the following equation: Ix' = Ix + mdx2, where Ix' is the moment of inertia about the X-axis in the second frame of reference, Ix is the moment of inertia about the X-axis in the first frame of reference, that measured by the inertial measurement unit 3, m is the mass of vehicle 1, and dx is the distance between the position of the inertial measurement unit 3 and the center of mass of vehicle 1 along the first X-axis. The device 100 according to the invention operates similarly for the other two axes Y and Z, depending, as appropriate, on the distances dy and dz that separate, along each of these axes, the position of the inertial measurement unit 3 and the center (or center of mass) of vehicle 1.Thus, at the end of this second step, the device 100 according to the invention has advantageously determined the moments of inertia of the vehicle 1 with respect to each of the axes X, Y and Z in the second Cartesian frame whose origin is at the center (or center of mass) of the vehicle 1.

[0027] Finally, according to a third step of the process according to the invention, the device 100 according to the invention manages the operation of the head-up display equipment 2 based on the data it determined during the previous step of the process. Advantageously, this data can be used to precisely orient the information displayed by the head-up display 2 according to the movements of the vehicle 1. Furthermore, due to the positioning of the inertial measurement unit 3 as close as possible to the head-up display 2, the delay induced by the data transmission latency is advantageously minimized.

[0028] Thus, thanks to the method and device according to the invention described above, a solution exists to improve the accuracy of the positioning of information displayed by a vehicle's head-up display system according to the vehicle's movements. In this way, the method and device according to the invention contribute to the provision of more ergonomic and safer motor vehicles.

Claims

Demands

1. A method for managing, by means of a computer device (100) installed on board a motor vehicle (1), the operation of a head-up display (2) of the vehicle, the vehicle comprising an inertial measurement unit (3) arranged at the front of the vehicle's passenger compartment on the driver's side, characterized in that the method comprises the steps of: i. obtaining data characterizing the moment of inertia of the vehicle with respect to at least one axis of a first Cartesian reference frame which are generated by the inertial measurement unit (3); ii. determining, as a function of the data obtained during step i), data characterizing the moment of inertia of the vehicle with respect to at least one axis of a second Cartesian reference frame; and iii. managing the operation of the head-up display (2) as a function of the data determined during step ii).

2. A method according to claim 1, characterized in that step ii) is carried out using at least one equation defined in accordance with the parallel axes theorem.

3. A method according to any one of the preceding claims, characterized in that the origin of the second reference frame is located at the center of mass of the vehicle.

4. Device (100) for managing the operation of a head-up display device (2) of a motor vehicle (1), the vehicle comprising an inertial measurement unit (3) arranged at the front of the vehicle's passenger compartment on the driver's side, characterized in that the device comprises at least one information processing unit (101), comprising at least one processor, and a data storage medium (102) configured to implement a method according to any one of the preceding claims.

5. Computer program comprising program code instructions for carrying out the steps of a process according to any one of claims 1-3 when said program is executed by at least one processor.

6.

7.

8.

9.

10. Support usable in a computer, characterized in that a program according to claim 5 is stored thereon. Motor vehicle (1) comprising a head-up display device (2), characterized in that the vehicle (1) comprises an inertial measuring unit (3) arranged at the front of the vehicle's passenger compartment on the driver's side and a device (100) according to claim 4. Vehicle (1) according to claim 7, characterized in that the inertial measuring unit (3) is arranged at a distance from a driver's instrument cluster of between one and fifty centimeters. Vehicle (1) according to claim 8, characterized in that the inertial measuring unit (3) is integrated into the instrument cluster. Vehicle (1) according to claim 7, characterized in that the inertial measurement unit (3) is arranged in a housing which integrates at least one optical component of the head-up display equipment (2).

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