Vehicle and procedures for controlling a vehicle

Abstract

A vehicle comprising: an environment monitor with multiple sensors for detecting predefined safety risks associated with several potential destination regions around the vehicle as the vehicle moves along a roadway, wherein the environment monitor selects one of the potential destination regions with a substantially lowest safety risk as a target area; a path determination unit that compiles several plausible paths between the vehicle and the target area, monitors predefined safety risks associated with the several plausible paths, and selects one of the plausible paths with a substantially lowest safety risk as a target path, wherein the path determination unit compiles the plausible paths according to a current speed and a maximum yaw rate for the vehicle;a collision detector to detect a collision between the vehicle and another object and a stability control system configured to autonomously steer the vehicle onto the target path when the collision is detected.

Description

The present invention relates generally to autonomous vehicle control and more specifically to planning and following a path after a collision, which reduces the risk of secondary crash events. Several vehicle control systems currently exist that are used to enhance a vehicle operator's driving capabilities, such as anti-lock braking systems (ABS), traction control systems (ASR), and stability control systems (SC systems). Examples of stability control systems include electronic stability control systems (ESC systems) (sometimes referred to as yaw stability control systems (YSC systems)) and roll stability control systems (RSC systems). ESC systems are sometimes also called ESP systems (ESP = electronic stability program) or DSTC systems (DSTC = dynamic stability and traction control). Furthermore, active safety systems are known from the prior art DE 10 2011 115 223 A1, which are designed to reduce kinetic energy in the event of an unavoidable collision, particularly through measures such as a multi-collision brake. Stability control systems are used to maintain controlled and stable vehicle movements for improved vehicle and occupant safety. These systems are often employed to maintain control of a vehicle while following the driver's intended course, preventing the vehicle from skidding and / or mitigating or preventing a rollover. A yaw stability control system, for example, typically compares the driver's intended course, based on the steering angle, with the vehicle's path as determined by motion sensors located on the vehicle. By adjusting the braking force at each corner of the vehicle and the vehicle's traction, the desired course can be maintained. Existing stability control systems correct unwanted vehicle movement caused by tire force disturbances (TFD), such as a tire force differential due to road surface disturbances or an imbalance between a driver's intentions and the road surface conditions. This imbalance typically occurs when there is a significant difference between the lateral forces acting on the vehicle at the front and rear tires (referred to as the lateral tire force differential), or a significant difference between the longitudinal tire forces of the right and left tires (referred to as the longitudinal tire force differential), or a combination of these. An unwanted yaw motion can also be caused by a yaw moment disturbance, which occurs when a vehicle experiences a force disturbance other than a tire force disturbance. A body force disturbance (BFD) can occur when a vehicle strikes a stationary object, such as a tree, or when the vehicle is struck by another moving object, such as a vehicle. A body force disturbance can also occur when the vehicle is subjected to a sudden, strong gust of wind acting on the vehicle body. While the magnitude of a tire force disturbance is limited by the driving condition of the road surface, the magnitude of a body force disturbance can be essentially unlimited.The collision of two moving vehicles, for example, can cause a body force disturbance of a magnitude several times greater than the total tire forces. Yawing motion can be induced when a vehicle experiences a body force disturbance from an external source, resulting in an altered vehicle trajectory or path, which can lead to a secondary collision event. In many situations, the risk of injury or damage from a secondary event can be much greater than from the primary event. Stability control systems assist a driver in continuing an intended action or trajectory. However, as a result of the impending or actual onset of a vehicle body force disturbance, a driver may panic and perform inappropriate or drastic driving actions in an attempt to avoid experiencing the external body force disturbance, which could lead to further undesirable events. Some studies have shown that approximately one-third of all vehicle-to-vehicle collisions resulting in serious injuries involve more than one impact. A relatively minor initial impact is very often followed by a severe second impact.This second collision can involve one of many types of collisions, such as vehicle-vehicle collisions, vehicle-object collisions, "tripped rollover" (rolling over an obstacle) or "untripped rollover" (rolling over without impact from an obstacle), and leaving the road. It would be desirable to react automatically to collision events, while taking into account the possibility of incorrect driver action in such a way as to reduce the probability and / or severity of secondary collision events. BRIEF SUMMARY OF THE INVENTION In one aspect of the invention, a vehicle comprises an environmental monitor with multiple sensors for detecting predefined safety risks associated with several potential destination regions around the vehicle as the vehicle travels along a roadway. The environmental monitor selects one of the potential destination regions with the substantially lowest safety risk (e.g., risk of a secondary collision) as a target area. A path determination unit compiles several plausible paths between the vehicle and the target area, monitors predefined safety risks associated with the several plausible paths, and selects one of the plausible paths with the substantially lowest safety risk as a target path. A collision detector detects a collision between the vehicle and another object.A stability control system is configured to autonomously steer the vehicle onto the target path when a collision is detected. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 depicts an initial collision and a safe path to follow after the collision. Fig. 2 is a diagram showing a grid used to identify a safest area and the safest path to reach it. Fig. 3 is a block diagram showing an embodiment of a device according to the present invention. Fig. 4 is a flowchart showing a preferred method of the invention. Fig. 5 is a block diagram showing an alternative embodiment. DETAILED DESCRIPTION OF PREFERRED EXECUTION FORMS If a vehicle experiences a collision that may have put it on a course where it will hit another object or move along an unfavorable path (e.g., a lane with heavy traffic or an unsafe situation, such as a lake or a steep slope), according to the present invention, an autonomous vehicle control system, such as torque vectoring, active steering, active braking, or active throttle control, is activated to initiate a path correction measure to avoid the unfavorable path. A device of the invention can prevent further occupant injury after a primary crash. A detection system is used to monitor the environment and identify a low-risk area (LRA) with a substantially lowest risk of potential secondary crashes if the host vehicle were to move into this area. A plausible path determination unit compiles all the plausible paths that could be followed to reach the low-risk LRA. A path planning system, operating in or with the path determination unit, selects a path with a substantially lowest safety risk from all the plausible paths. The identification of a low-risk LRA and the selection of a path are performed essentially continuously while the vehicle is in motion, so that they can be used immediately in the event of a collision.A collision detection system detects the occurrence of a collision. In response to the collision, a vehicle stabilization device is activated to follow the selected path. Preferably, the detection system and the path planning system continue to monitor changing risks, and the selected path is updated accordingly. The detection system can preferably assess predefined safety risks in order to identify the area with the lowest risk and the path with the lowest risk based on information from radar sensors, lidar sensors, ultrasonic sensors, vision sensors (cameras), night vision and other sensors (many of which may already be present on a vehicle in conjunction with a collision warning system, adaptive cruise control system or reversing parking aid) or from remote information obtained from vehicle infrastructure systems, vehicle-to-vehicle communication systems, cloud communication systems or navigation and digital mapping systems. The lowest-risk BGR area can be identified by excluding areas in an environmental grid that have a high probability of a secondary collision or other hazards, using all available environmental sensors. Such hazards could include an area or path leading to a lake, a steep rise, a sloping terrain feature, a region with heavy oncoming traffic or a potential vehicle-to-vehicle collision, an area that could cause a tripped rollover, or a path leading to fixed objects such as poles, trees, or buildings. The collision detector can include vehicle crash sensors, vehicle motion sensors, or other sensors for stability control after a collision. The vehicle stability control used to follow the desired path after a collision can preferably be identical to the one used in the vehicle to provide driver assistance before the collision event. The invention continuously calculates the lowest-risk paths while driving and then uses a first collision as a trigger to initiate autonomous driving functions, such as torque vectoring, active steering, active braking, active throttle control, or active steering assist (EPAS).An autonomous driving function, activated after a collision, can compel a vehicle to move along a safe path, even in the absence of driver control commands or inappropriate actions. If the driver correctly steers the vehicle in the safe direction, the invention can facilitate timely driver intervention. Furthermore, if the vehicle's kinetic energy is sufficiently reduced to bring it to a stop within the area of ​​least risk, the autonomous driving function can also be used to bring the vehicle to a halt. Now, with reference to Fig. 1, a host vehicle 10 is moving along a roadway 11 towards an intersection. A second moving vehicle 12 is shown entering the intersection, causing a collision, with the impact occurring at position 13. The collision alters the trajectory of the host vehicle 10. The vehicle 10 could then take a course that results in a secondary collision with, for example, a stationary pole 14, nearby vehicles 15 and 16, or a pond 17. The driver may be unable to steer into a safe area or may unintentionally initiate control actions inconsistent with avoiding a secondary collision. Therefore, the present invention automatically identifies a safe area 18 with the lowest safety risk, together with a path 19 offering the highest probability of safely reaching the area 18.Using remote sensing to identify potential safety risks, the present invention employs a grid 20 divided into several potential target regions laid out over the area in the immediate vicinity of the vehicle 10. Some of the potential target regions are numbered 21-25, 28, 31-34, 38, and 40-44. Each potential target region lies at a specific heading angle and distance from the vehicle 10 and preferably has a width and length approximately the same size and shape as a contact area of ​​the vehicle 10. Using remote object detection, classification, and tracking, each detected occurrence of a safety risk is mapped onto the corresponding potential target regions. Any locations where a secondary collision event is likely to occur (e.g.,Areas with a stationary obstacle or a moving object, or with unsafe road surface properties or steep gradients, can be excluded from consideration as either a safe destination area or a safe route. Consequently, several regions 40-43 are shaded to indicate that they should be avoided when selecting the destination area or route. For any regions not excluded from consideration, other security risks can be quantified, or other factors can be taken into account when assigning a risk value. For example, a particular risk value can reflect a region's proximity to other regions that pose known security risks. In Fig. 2, region 44 was assessed as having the lowest security risk. Consequently, within the scope of the present invention, it becomes a target area with the lowest risk BGR. Once the target area BGR is selected, several plausible paths 45-47 are compiled (i.e., defined) based on various characteristics of the vehicle control system, a detected vehicle state, and the avoidance of any excluded regions (e.g., region 41). The safety risks associated with each plausible path are monitored, and the assessment of these risks is used to select a target path with the substantially lowest safety risk. The grid 20 is preferably continuously assessed during vehicle movement so that the target area and target path are continuously updated, making them immediately available upon detection of a collision event. In response to the collision, a stability control function is initiated to autonomously steer the vehicle onto the target path, as described below.If possible, the stability control can also stop the vehicle within the target area. Fig. 3 shows a preferred device of the invention, comprising an environmental monitor 50 equipped with various sensors 51 for detecting predefined safety risks associated with the potential target regions around the vehicle. Based on the sensor inputs, the environmental monitor 50 assesses several hazards, which are recorded in a hazard block 52 and correlated with respective regions of the grid 20. Based on the assessment of the hazards 52 in the grid 20, a target area is selected and then identified to a path determination unit 53. Several plausible paths 54 are compiled in the path determination unit 53, and the safety risks associated with each path are monitored based on information from the sensors 51 and several vehicle sensors (which can, for example, be used to determine the vehicle's maneuverability).The plausible path with the lowest safety risk is selected as the target path, and this target path is identified to a post-impact path assistant controller 56. A collision detector 57 is coupled to the controller 56 and provides a trigger signal when it detects a collision between the vehicle and another object. The controller 56 does nothing with the continuously generated target path information until a collision is detected. At that point, the controller 56 interacts with a stability control system 58 to autonomously steer the vehicle onto the target path. A general method of the invention is shown in Fig. 4, wherein in step 60 the environment near the vehicle is monitored for predefined safety risks. In step 61, risks are assigned to regions in the grid. In step 62, the region with substantially the lowest safety risk is selected as a target area. In step 63, all plausible paths between the vehicle and the target area are found, and in step 64 the path with the lowest associated safety risk is selected as the safest path. In step 65, a check is performed to determine whether a collision has been detected. If no collision has occurred, the procedure returns to step 64 to essentially continuously assess the vehicle's surroundings and update the target area and path. Once a collision is detected, in step 66 the vehicle autonomously follows the safest path (or assists the driver in their efforts to follow the path). If the stability control actuation is capable of stopping the vehicle within the target area in step 67, it preferably does so. After step 66, the procedure may also preferably return to step 60 to continue monitoring the surroundings in order to reselect a target area and safest path, as the risk situation may change in the aftermath of the collision. Fig. 5 shows a more detailed embodiment of the invention. A post-impact path assistant controller 70 can be coupled with a yaw rate sensor 71, velocity sensors 72 (e.g., for both vehicle speed and the speeds of individual wheels), a lateral acceleration sensor 73, a vertical acceleration sensor 74, a roll rate sensor 75, a steering angle sensor 76, a longitudinal acceleration sensor 77, a pitch rate sensor 78, a steering angle position sensor 79, and a load sensor 80. A GPS navigation system with a digital map 81 is also connected to the controller 70 as a potential source of safety risk information (e.g., location of fixed obstacles or topology).Security risk information from sources external to the vehicle can also be obtained via a wireless data link 82 to couple the control unit 70 with a vehicle-to-vehicle communication system (V2V communication system) 83 or a cloud-based infrastructure 84. The vehicle further includes a passive safety system 85 with multiple object detection sensors 86, such as radar, lidar, or vision-based remote sensors. The safety system 85 also includes passive countermeasures 87, such as airbags, and collision detection sensors 88 (which may consist of dedicated sensors, such as accelerometers, or may include selected sensors 71-80) to control the deployment of the countermeasures 87. The stability control system of the present invention can comprise a brake control unit 90, an engine control unit (ECU) 99, a suspension control unit 100, and / or a steering control unit 101. As is known in the art, the brake control unit 90 can individually control brake actuators 91-94 at individual wheels to achieve a braking / steering function and ultimately bring the vehicle to a complete standstill. The brake control unit 90 can preferably be shared with other stability control systems, such as an ABS system 95, a YSC system 96, an ASR system 97, and a RSC system 98. During operation, objects and other safety hazards associated with regions around the vehicle are identified and tracked by the object detection sensors 86 and incorporated into a grid by the control unit 70. After identifying an area with the lowest risk, the control unit 70 determines plausible paths to reach the target area by assessing the current vehicle speed and maximum yaw rate, for example, to determine the maximum braking / steering input that can be achieved. If a collision is detected by the sensors 88, the control unit 70 activates one of the stability controls, such as the brake control 90, to steer the vehicle onto the previously identified target path and potentially bring the vehicle to a stop within the target area.

Claims

A vehicle comprising: an environment monitor with multiple sensors for detecting predefined safety risks associated with several potential destination regions around the vehicle as the vehicle moves along a roadway, wherein the environment monitor selects one of the potential destination regions with a substantially lowest safety risk as a target area; a path determination unit that compiles several plausible paths between the vehicle and the target area, monitors predefined safety risks associated with the several plausible paths, and selects one of the plausible paths with a substantially lowest safety risk as a target path, wherein the path determination unit compiles the plausible paths according to a current speed and a maximum yaw rate for the vehicle;a collision detector to detect a collision between the vehicle and another object and a stability control system configured to autonomously steer the vehicle onto the target path when the collision is detected. Vehicle according to claim 1, wherein the previously defined safety risks include stationary obstacles and moving objects that represent a potential collision. Vehicle according to claim 1, wherein the previously defined safety risks include unsafe surface properties and steep gradients. Vehicle according to claim 1, wherein the control actuation is configured to stop the vehicle in the target area. Vehicle according to claim 1, wherein the environment monitor and the path determination unit each select the target area or the target path before the collision occurs. Vehicle according to claim 1, wherein the potential destination regions consist of a predetermined grid defined in relation to the vehicle. Vehicle according to claim 1, wherein the multiple sensors include at least one sensor selected from the group consisting of a radar sensor, a lidar sensor, an ultrasonic sensor, an optical sensor, a night vision sensor, a remote communication system and a geopositioning system. A method for controlling a vehicle comprising the following steps: monitoring predetermined safety risks associated with several potential destination regions around the vehicle while the vehicle is moving along a roadway; selecting one of the potential destination regions with the lowest substantially low safety risk as a destination area; determining several plausible paths between the vehicle and the destination area, depending on the current speed and a maximum yaw rate for the vehicle; monitoring predetermined safety risks associated with the several plausible paths; and selecting one of the plausible paths with the lowest substantially low safety risk as a destination path.Detecting the occurrence of a collision between the vehicle and another object and activating autonomous path control to follow the target path to the target area in response to the collision detection. The method of claim 8, wherein the previously defined safety risks include stationary obstacles and moving objects that represent a potential collision.

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