TARGET VEHICLE FOR ADAS TESTING

Abstract

A target vehicle, for example a two-wheeled vehicle, for mounting onto an ADAS (Advanced Driver Assistance System) testing platform is provided. The target vehicle comprises one or more sensors and an actuation assembly comprising an actuator. The sensors are arranged to measure a parameter relating to the dynamics of the target vehicle and may for example comprise accelerometers. The actuation assembly adjusts the tilt of the target vehicle in dependence on the output of the sensor(s), for example by means of a control unit. The tilting of the vehicle during cornering may thus be simulated. The measuring of such a parameter and the adjusting of the tilt may be conducted remotely from the testing platform. The sensor(s), control unit and actuator assembly may be self-contained within the target vehicle. A method of modeling a VRU (Vulnerable Road User) for ADAS testing is also provided.

Claims

1. A target vehicle for mounting onto an ADAS testing platform, the target vehicle comprising: a sensor arranged to measure a parameter relating to the dynamics of the target vehicle; and an actuation assembly arranged to adjust the tilt of the target vehicle in dependence on the output of the sensor.

2. The target vehicle of claim 1, wherein the target vehicle further comprises: a control unit configured to control the actuation assembly to adopt a simulation tilt angle, the magnitude of the simulation tilt angle being dependent on the output of the sensor.

3. The target vehicle of claim 2, wherein the simulation tilt angle is the tilt angle necessary to counteract the overturning moment exerted on the target vehicle during movement of the platform around a corner.

4. The target vehicle of claim 1, wherein the target vehicle further comprises: a base for mounting in a fixed position relative to the testing platform, and a tiltable body for tilting relative to the base, wherein the sensor is located on the tiltable body such that the sensor moves during tilting of the target vehicle.

5. The target vehicle of claim 2, wherein the sensor is an accelerometer configured to measure lateral acceleration of the target vehicle.

6. The target vehicle of claim 5, wherein the control unit is configured to maintain the simulation tilt angle at which the lateral acceleration measured by the accelerometer is minimized.

7. The target vehicle of claim 1, wherein the actuation assembly comprises: a rotary actuator, and wherein rotation of the rotary actuator affects the tilt of the target vehicle.

8. The target vehicle of claim 7, wherein the actuation assembly further comprises: a pinion engaged with a rack, the pinion being driven by the rotary actuator such that rotation of the pinion moves the pinion along the rack to tilt the target vehicle.

9. The target vehicle of claim 8, wherein the rack is a toothed belt.

10. A two-wheeled target vehicle for mounting onto an ADAS testing platform, the target vehicle being arranged to simulate the tilting of a two-wheeled vehicle during cornering, wherein the target vehicle comprises: a sensor arranged to measure a parameter of the target vehicle dynamics as it is moved by the testing platform; an actuation assembly arranged to adjust the tilt of the target vehicle; and a control unit configured to control the actuation assembly to adopt a simulation tilt angle, the magnitude of the simulation tilt angle being dependent on the output of the sensor, wherein the sensor, control unit, and actuator assembly are self-contained within the target vehicle and are independent of the platform to which the target vehicle is mounted.

11. A target assembly comprising a testing platform onto which the target vehicle of claim 1 is mounted.

12. A target assembly comprising a testing platform onto which the target vehicle of claim 10 is mounted.

13. An assembly for tilting a target vehicle, the assembly comprising: a sensor for attaching to a target vehicle to measure a parameter relating to the dynamics of the target vehicle; an actuation assembly arranged to adjust the tilt of the target vehicle in dependence on the output of the sensor; and a control unit configured to control the actuation assembly to adopt a simulation tilt angle, the magnitude of the simulation tilt angle being dependent on the output of the sensor.

14. A method of modeling a VRU for ADAS testing using a target vehicle mounted on a moveable testing platform, the method comprising the steps of: measuring a parameter relating to the dynamics of the target vehicle; and adjusting the tilt of the target vehicle in dependence on the output of the sensor, wherein the steps of measuring and adjusting are conducted remotely from the testing platform.

15. The method of claim 14, wherein the steps of measuring and adjusting all take place in the target vehicle.

16. A target assembly comprising a testing platform and a target vehicle mounted thereon, the target assembly comprising: a sensor arranged to measure a parameter relating to the dynamics of the target assembly; and an actuation assembly arranged to adjust the tilt of the target vehicle in dependence on the output of the sensor.

17. The target assembly of claim 16, wherein the sensor is in the testing platform and the target assembly comprises a communication module for communicating signals between the platform and the target vehicle.

18. The target assembly of claim 17, wherein the output of the sensor is also used for control of the platform.

Description

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

[0028] Embodiments of the present invention will now be described by way of example with reference to the accompanying schematic drawings of which:

[0029] FIG. 1 shows a perspective view of a target assembly incorporating a target vehicle according to a first embodiment of the invention;

[0030] FIGS. 2 and 3 show a frontal view of the target assembly in FIG. 1 when upright and tilting respectively;

[0031] FIG. 4 shows the target vehicle of the first embodiment but with the soft body removed;

[0032] FIGS. 5 and 6 show a frontal view of the target vehicle in FIG. 4 when upright and tilting respectively, but with the tires removed;

[0033] FIG. 7 is a schematic showing the control unit in the target vehicle of the first embodiment; and

[0034] FIGS. 8 and 9 are sectional views through A-A in FIG. 4, showing part of the actuation assembly.

DETAILED DESCRIPTION

[0035] FIG. 1 is a perspective view of a target assembly (also referred to as a guided soft target (GST)) 1. The GST 1 comprises a low-profile testing platform 3 onto which is mounted a target vehicle 5 according to a first embodiment of the invention.

[0036] In the first embodiment of the invention, the target vehicle 5 is seeking to replicate a moped, which is a type of target often referred to as a vulnerable road user (VRU). The target vehicle 5 comprises a sacrificial soft body 7 (made from close cell polyethylene foam) that closely resembles a real-world moped. The soft body 7 encloses a framework 9 and tilting assembly 11 (discussed in more detail in FIGS. 4 to 6 below). In the first embodiment, a dummy-rider 13 is sat on the target vehicle 5.

[0037] FIGS. 2 and 3 show the GST 1 in frontal view during two different scenarios. In FIG. 2, the testing platform 3 is traversing level ground in a straight line. The moped is therefore upright, with its center of mass above the wheels 15. In FIG. 3, the testing platform 3 is on the same level ground but is traversing a curved path, for example around a corner in a road. In the first embodiment of the invention, the target vehicle 5 is configured so that it tilts (i.e. leans over from the upright direction) as the testing platform 3 traverses the curved path. This ensures the target vehicle 5 closely replicates the real-world movement the moped would exhibit. Features of the target vehicle 5 that enable this functionality will now be described with reference to FIGS. 4 to 7.

[0038] Referring initially to FIG. 4, this illustrates the structure of the target vehicle 5 beneath the soft body 7. The structure comprises a framework 9 of tubing onto which the soft body 7 (not shown in FIGS. 4 to 6) would be attached. The tubing connects with front and back wheels 15a, 15b. The structure comprises a base portion 17 having four magnetic fasteners 19 for mounting the target vehicle 5 onto the testing platform 3. The magnetic fasteners 19 allow the target vehicle 5 to readily detach from the testing platform 3 in the event of a collision during ADAS testing.

[0039] A hinge axis 21 passes through two co-axial hinges 23, positioned low down on the target vehicle 5, and connecting the base portion 17 to the framework 9 of tubing above. The framework 9 above the base portion 17 is tiltable about the hinges 23 under the action of a tilting assembly 25.

[0040] The tilting assembly 25 comprises an actuator 27, two accelerometers 29, and a control unit 31 (see FIGS. 5-7). The accelerometers 29 and the control unit 31 are located in a housing attached to the framework 9. The accelerometers 29 are shown schematically in FIGS. 5 and 6. The accelerometers 29 are mounted on the framework 9 such that when the target vehicle is upright, the accelerometers 29 lie along the vertical axis in the absolute frame (Z) and the local frame (Zc) relative to the target vehicle. In other embodiments (not shown), the accelerometers 29 may be in a location off from the vertical axis, and the control unit is arranged to compensate for that offset when processing the output from the accelerometers 29.

[0041] Each accelerometer 29 is arranged to measure lateral acceleration a_Xc, i.e. acceleration along the lateral direction Xc relative to the target vehicle 5. Two accelerometers 29 are provided to average out any noise in the signal and to average out any offset between the two accelerometers 29. During use, when the target vehicle 5 is mounted on a moving testing platform 3, the output of the accelerometers 29 is fed to the control unit 31. If the testing platform 3 begins to traverse a curved path, the accelerometers 29 will begin to experience an increase in lateral acceleration a_Xc. The control unit 31 is arranged to control the rotary actuator 27 to adjust the tilt of the testing vehicle 5 (e.g., the tilt of the tiltable framework 9 of the testing vehicle 5), such that the lateral acceleration a_Xc is minimized.

[0042] The control unit 31 carries out the control process shown in FIG. 7 to which reference is now made. The control unit 31 receives the signals from the accelerometers 29 (via a Kalman filter 35 to reduce signal noise). The control unit 31 also receives a target lateral acceleration threshold of 0 g. A PID controller 37 receives a measure of the difference between this target value and the measured values from the accelerometers 29. The PID 37 provides an output signal, indicative of maintaining the target threshold lateral acceleration of 0 g, and this output signal is sent to the actuator 27 to adjust the tilt in a manner that reduces the lateral acceleration a_Xc to the threshold value. The control unit 31 thus contains a control loop that seeks to maintain a simulation tilt angle θ of the target vehicle at a value then results in no lateral acceleration being measured by the accelerometers 29.

[0043] In the first embodiment of the invention, the control unit 31 also contains an intermediate actuator-protection module 38 for protecting the actuator 27 from excessive electrical currents, although it will be appreciated that this protection module 38 is optional and may not necessarily be required in other embodiments. The control unit 31 also comprises an end-stop control module 39, which is arranged to prevent the actuator 27 assembly driving beyond its end-stop positions. Again, it will be appreciated that this end-stop control module 39 is optional and may not necessarily be required in other embodiments of the invention.

[0044] Referring back to FIGS. 5 and 6, these illustrate the accelerometers 29 and other parts of the target vehicle 5 in upright and tilted configurations respectively. As shown in FIG. 6, the lateral acceleration is minimized when the resultant force Rf from cornering and from gravity, is directed along the local vertical axis Zc of the target vehicle (which is the same as the direction through the plane of the wheels). This is the tilt angle θ necessary to counteract the overturning moment exerted on the target vehicle during movement of the platform 3 around the corner, and is therefore an accurate representation of the actual tilt a rider tends to adopt when cornering a moped. In the context of the illustrated embodiment, the tilt angle θ (also referred to as the lean angle) is measured between the vertical axis Zc of the vehicle and the vertical axis Z in the absolute reference frame.

[0045] FIGS. 8 and 9 illustrate the actuation assembly 25 in more detail and is a section view along A-A of FIG. 4. The assembly 25 comprises the rotary actuator 27 orientated along the lower part of the frame, and generally along the fore-aft direction (Yc) of the testing vehicle 5. The use of a rotary actuator 27 and its orientation in this manner facilitates a relatively compact arrangement that does not need to protrude from the soft body 7.

[0046] A pinion gear 43 is mounted to the output shaft of the rotary actuator 27. The pinion gears 43 mesh with a rack in the form of a toothed belt 45. The toothed belt 45 is fastened at either end 45a, 45b, to the base portion 17 of the target vehicle 5 and runs through idler gears 46 mounted on lateral arms 48. To adjust the tilt of the target vehicle 5, the pinion 43 is rotated, thereby drawing the pinion and the remainder of the tiltable part 9 of the target vehicle 5 along the toothed belt 45 in the direction and magnitude specified by the control unit 31, such that it tilts about the hinge axis 21 of the hinges 23.

[0047] The first embodiment of the invention provides several advantages over known VRU target vehicles. Firstly, the equipment necessary to achieve the tilting of the target vehicle is self-contained on the target vehicle. It is independent of the platform on which it is mounted. This enables the target vehicle to be readily used on various different platforms and avoids the need for communication or other interfacing between a platform and the testing vehicle. Secondly, the arrangement used in this embodiment of the invention has been found to provide especially realistic tilt behavior because it measures a real-time parameter that is indicative of the tilt a rider would adopt (e.g., it measures a parameter relating to the dynamics of the vehicle (the lateral acceleration) as it is experienced by the tilting part of the target vehicle). Finally, the actuator assembly in the first embodiment is compact and has a relatively low radar signature outside the soft body of the moped; it is therefore especially beneficial for ADAS testing.

[0048] Whilst the present invention has been described and illustrated with reference to a particular embodiment, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. By way of example, different sensors may be used. In a further embodiment (not shown), the target vehicle may include a GPS sensor for measuring the spatial movement of the target vehicle. From that measurement of spatial movement, for example from a measurement of the yaw of the target vehicle, the appropriate tilt behavior may be calculated and the actuator assembly instructed accordingly. By way of another example, the target vehicle may be modeling a different single-track VRU such as a push bike (bicycle) or a differently shaped motorbike. In another embodiment of one of the aspects of the invention, the sensor may be a pre-existing sensor on the testing platform that was already used for controlling the testing platform (e.g. a GPS sensor). In this embodiment, a communications module is provided for relaying the output of the sensor and/or the control unit, to the actuation assembly on the target vehicle, to provide a tiling actuation signal.

[0049] Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.