Method, device and electronic device for generating target tracking path

Abstract

The present invention discloses a method, device, and electronic device for generating a target tracking path. The method includes: obtaining the relative position of the target vehicle in the current DR coordinate system of the ego vehicle; converting the relative position to the current DR coordinate system of the ego vehicle, and updating the tracking path in the DR coordinate system according to the conversion result; the tracking path includes a smoothed path stored in a smoothed cache and a path to be smoothed stored in a buffer to be smoothed; after the number of path point DR coordinates in the buffer to be smoothed reaches a capacity threshold, when new path point DR coordinates are stored, the DR coordinates of the first path point in the buffer to be smoothed are smoothed and then stored in the smoothed path; the smoothed path in DR coordinates is converted to the ego vehicle coordinate system according to the current DR coordinates of the ego vehicle to form a tracking path in the ego vehicle coordinate system. The present invention can not only accurately restore the target path, but also generate a smooth and stable target tracking path.

Description

Technical Field

[0001] The present invention relates to the field of autonomous driving technology, and in particular to a target tracking path generation method, device, and electronic equipment. Background Art

[0002] Autonomous vehicles rely on their sensors to detect the target's position and velocity in real time, record and restore the target's path, and then use a series of strategies to stably follow the target. Because the target's motion cannot be accurately estimated, generating a tracking path often presents many difficulties. Summary of the Invention

[0003] The purpose of the present invention is to provide a method, device and electronic device for generating a target tracking path based on a recursive coordinate system in order to address the technical defects in the prior art.

[0004] A first aspect of the present invention provides a method for generating a target tracking path, comprising the steps of:

[0005] Get the current relative position of the target vehicle in the vehicle coordinate system;

[0006] Convert the relative position to the current DR coordinate system of the vehicle, and update the tracking path in the DR coordinate system according to the conversion result; the tracking path includes the smoothed path stored in the smoothed buffer and the path to be smoothed stored in the buffer to be smoothed;

[0007] After the number of path point DR coordinates in the buffer to be smoothed reaches a capacity threshold, when new path point DR coordinates are stored, the path point DR coordinate that first enters the buffer to be smoothed is smoothed and then stored in the smoothed path;

[0008] The smoothed path in the DR coordinate is converted to the vehicle coordinate system according to the current DR coordinate of the vehicle to form a tracking path in the vehicle coordinate system.

[0009] A second aspect of the present invention provides a target tracking path generation device, comprising:

[0010] The DR coordinate conversion module is used to obtain the relative position of the target vehicle in the current vehicle coordinate system and convert the relative position to the current DR coordinate system of the vehicle;

[0011] A coordinate updating module is used to update the tracking path under the DR coordinate according to the conversion result; the tracking path includes the smoothed path stored in the smoothed buffer and the path to be smoothed stored in the buffer to be smoothed;

[0012] a smoothing processing module configured to, after the number of path point DR coordinates in the buffer to be smoothed reaches a capacity threshold, smooth the first path point DR coordinate in the buffer to be smoothed when a new path point DR coordinate is stored, and then store the smoothed path point DR coordinate;

[0013] The tracking path generation module is used to convert the smoothed path in the DR coordinate system into the ego vehicle coordinate system according to the current DR coordinate system of the ego vehicle to form a tracking path in the ego vehicle coordinate system.

[0014] According to a third aspect of the present invention, an electronic device is provided, comprising at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the target tracking path generation method.

[0015] The target tracking path generation technology based on a recursive coordinate system described in the present invention converts the relative position of the target in the ego-vehicle coordinate system to a recursive (Dead Reckoning, DR) coordinate system. Since recursive coordinates are free of sudden changes and have very small errors in a short period of time, and the task of tracking the target is generally maintained within a relatively short visual distance and is not sensitive to cumulative errors, it can maintain the advantages of the global coordinate path generation method, that is, accurately restore the target path, without the problem of positioning sudden changes that are difficult to avoid with the global coordinate path generation method.

[0016] The present invention uses two data cache areas to respectively store the smoothed path and the path to be smoothed in the target DR coordinate system. Through the dynamic smoothing scheme of two-level cache, the dynamic smoothing effect of the path is guaranteed, and a smooth and stable target tracking path can be generated, overcoming the problem of target fluctuation and ensuring that there is no mutation problem in the path that the vehicle is about to travel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of a target tracking path generation method according to an embodiment of the present invention;

[0018] Figure 2 Schematic diagram of the relationship between DR coordinates and vehicle relative coordinates according to an embodiment of the present invention;

[0019] Figure 3 A schematic diagram of the arrangement of a smooth path and a non-smooth path of a tracking path according to an embodiment of the present invention;

[0020] Figure 4 A schematic diagram of the arrangement of two-level caches of a cache tracking path according to an embodiment of the present invention;

[0021] Figure 5This is a structural diagram of a target tracking path generation device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] The path generation method based on relative coordinates relies only on the relative position of the real-time target given by the perception module. By connecting the relative positions of the ego vehicle and the target, a straight line containing only relative coordinate information can be obtained. This method regenerates a straight line path for each frame, without the need to maintain the existing path. It is easy to use and works well under simple working conditions. The disadvantage is that the ego vehicle will always track the real-time target along a straight line in a "shortcut" manner, and the ego vehicle can respond quickly to changes in the target vehicle. However, the straight line generated in real time often does not meet the vehicle kinematic constraints. When the ego vehicle uses an Ackerman steering chassis, it is difficult to track similar routes. In addition, even if a vehicle that can turn on the spot is used, when the target vehicle takes a curve or turns around, the ego vehicle still cannot restore the trajectory of the preceding vehicle. This will cause a collision risk when the ego vehicle does not have local obstacle avoidance capabilities.

[0024] Global coordinate-based path generation relies not only on the relative target position provided by the perception module but also on the ego vehicle's positioning. Based on its own positioning information, the ego vehicle converts the target vehicle's relative position into a global coordinate system and records it. The recorded path information uses the target's global coordinate position. As the vehicle tracks the recorded path frame by frame, it updates the global path in real time. Ideally, the ego vehicle can accurately restore the target's path, resulting in a highly accurate path.

[0025] Although the global coordinate-based approach can completely restore the actual path of the target vehicle and avoid the problems of the relative coordinate approach, the global coordinate maintenance approach is highly dependent on the positioning accuracy of the vehicle, especially the heading angle. In practical applications, due to the variability of the environment, it is difficult to ensure continuous stability of the positioning state. When the positioning suddenly jitters or deviates at a certain moment, the absolute position of the target recorded at that moment will have a corresponding deviation or jitter, resulting in inaccurate newly recorded paths. At the same time, the already recorded global path will also suddenly deviate or rotate relative to the target, affecting the control effect. There is even a risk of loss of control during high-speed tracking.

[0026] In addition, due to the limitations of perception of target recognition, the recorded global target position will inevitably fluctuate, and the recorded path will not be smooth, which will affect speed planning and control.

[0027] Therefore, the embodiment of the present invention proposes a target tracking path generation method as follows Figure 1As shown, the following steps are included:

[0028] Step S1, obtaining the current relative position of the target vehicle in the vehicle coordinate system;

[0029] Step S2, converting the relative position to the current DR coordinate system of the vehicle, and updating the tracking path in the DR coordinate system according to the conversion result; the tracking path includes the smoothed path stored in the smoothed buffer and the path to be smoothed stored in the buffer to be smoothed;

[0030] Step S3, after the number of path point DR coordinates in the buffer to be smoothed reaches a capacity threshold, when new path point DR coordinates are stored, smoothing the first path point DR coordinate in the buffer to be smoothed, and then storing it in the smoothed path;

[0031] Step S4: converting the smoothed path in DR coordinates to the vehicle coordinate system according to the current DR coordinates of the vehicle to form a tracking path in the vehicle coordinate system.

[0032] The tracking path in DR coordinates is updated according to the conversion results, including:

[0033] The DR coordinates of the relative position of the target are obtained as the conversion results, and the conversion results are arranged in a queue in chronological order and stored in the smoothed cache first. After the smoothed cache is filled, it is stored in the cache to be smoothed to complete the update operation of the tracking path under the DR coordinates.

[0034] When target tracking is initialized, the control module forms an interpolation path based on the current position of the vehicle and the starting position of the target, and uses an interpolation algorithm according to the vehicle coordinates, and stores it in the smoothed cache to be spliced ​​with the tracking path obtained during the target tracking process.

[0035] The interpolation path is an interpolation path in the DR coordinate system of the vehicle, or an interpolation path in the relative coordinate system of the vehicle.

[0036] The following is an introduction to specific embodiments:

[0037] In the embodiment of the present invention, the coordinates of the current recursive coordinate system of the vehicle are completely dependent on the coordinates calculated by the inertial navigation sensor, that is, the DR coordinates are P dr (x dr ,y dr ,θ dr ), the target relative coordinate calculated by the perception module is T r (x r ,y r ), according to the coordinate transformation, the DR coordinate T of the target in the recursive coordinate system can be calculated dr (xT dr ,y T dr ,θ T dr ):

[0038]

[0039]

[0040]

[0041] Where (x, y, θ) represents the horizontal and vertical coordinates and angles of the vehicle in a certain coordinate system, the subscripts r and dr represent the vehicle reference system and the ground reference system, respectively, and the superscript T represents the target position.

[0042] Unlike global coordinates, the DR coordinate system accumulates over time, and there will be a relatively large cumulative error compared to the real position, so it cannot be used continuously for a long time. However, the relative deviation between well-calibrated DR coordinates does not accumulate over time. Therefore, in scenarios with shorter distances, the relative relationship between DR coordinates is basically the same as the relative relationship between real coordinates, and therefore the relative position relationship relative to the ego vehicle is also basically similar. In the target tracking task, the ego vehicle is concerned with the relative relationship of each path point relative to itself. This "generate and use" approach reduces the impact of the inherent cumulative error of inertial navigation. Figure 2 As shown in the figure, the relationship between the DR coordinates of the ego vehicle (autonomous driving vehicle) and the target vehicle and the ego vehicle coordinates is as follows:

[0043] Among them, O dr X dr Y dr Indicates the DR coordinate system, X r 、Y r Indicates the horizontal and vertical coordinate directions of the vehicle coordinate system, when recording a series of DR coordinates of the target in the recursive coordinate system T dr (x T dr ,y T dr ,θ T dr ) can be calculated based on the vehicle coordinate P dr (x dr ,y dr ,θ dr ), each T dr Restore to the vehicle coordinate system and obtain the relative coordinate T r (x r ,y r ) is transmitted to the control module to restore and track the target path.

[0044] Specifically, a series of T r Convert T to DR coordinate system dr Save and then convert to relative coordinates T r In this way, when controlling the tracking path, we only need to pay attention to the path information of the target vehicle relative to the vehicle coordinate system.

[0045] If the relative coordinate T is not r Convert T to DR coordinate system dr To store, then for a series of relative coordinates T recorded when the vehicle is constantly moving r , which does not have a stable meaning. Therefore, in the embodiment of the present invention, the relative coordinate T r Convert T to DR coordinate system dr Storage is performed to ensure the stability of coordinates.

[0046] During the target tracking process, the target position information obtained by the perception module in the ego-vehicle coordinate system is converted into the ego-vehicle's current DR coordinate system to form the corresponding DR coordinates, so as to update and store the stored tracking path. By utilizing the characteristics of recursive coordinates that will not change suddenly and have very small errors in a short period of time, the task of tracking the target is generally maintained within a relatively short visual distance and is not sensitive to cumulative errors. Therefore, the advantages of the global coordinate path generation method can be maintained, that is, the target path is accurately restored, without the problem of positioning mutation that is difficult to avoid in the global coordinate path generation method.

[0047] When recording the target DR coordinates T dr When the vehicle is in motion, sudden braking, sudden steering and other actions are inevitable, which will cause the DR coordinates of the vehicle P dr There will be a momentary large fluctuation. At the same time, due to the limitation of the sensor or perception module on the tracking effect of the target, there will often be an estimated deviation of the target's relative position in scenes such as the target turning or making a U-turn (for example, when the target turns, the tracking point jumps from the rear of the target vehicle to the side of the target vehicle, etc.). In order to ensure a better tracking effect, it is necessary to smooth the recorded target DR coordinates.

[0048] In addition, due to the inherent characteristics of the control, the vehicle has a strong dependence on the path to be tracked not to have sudden jitters. Therefore, when smoothing the path, it is necessary to ensure that the path that the vehicle is about to traverse is stable and will not change suddenly due to smoothing, and on the other hand, it is necessary to ensure that the newly recorded target DR coordinates are all smoothed. Therefore, the embodiment of the present invention proposes two buffer areas for dynamic smoothing, namely a stable buffer area (smoothed cache) and a buffer area to be smoothed, which together constitute the tracking path of the vehicle, thereby ensuring that the path that the vehicle is about to traverse is stable and will not change suddenly, and at the same time ensuring that the newly recorded target DR coordinates are all smoothed. Due to the existence of the buffer to be smoothed, the recorded target positions are smoothed in order by weighted mean filtering that takes into account the previous and next data, so that the fluctuation of the path is reduced and a better tracking effect is achieved. The schematic diagram of the smoothed path is shown as follows. Figure 3 shown.

[0049] In order to achieve a smooth walking path of the vehicle during the tracking process, in the embodiment of the present invention, the number of target DR coordinates stored in the buffer to be smoothed is always kept constant, and the smoothed buffer B filt The amount of data only increases, and existing members do not change. This ensures a smooth path for the ego vehicle during tracking. When the target DR coordinates in the to-be-smoothed cache are smoothed, they are stored in the smoothed cache, ensuring that the path the ego vehicle (autonomous driving vehicle) will follow does not undergo sudden changes. Therefore, in this embodiment of the present invention, when it is determined that the number of pathpoint DR coordinates in the to-be-smoothed cache has reached a capacity threshold and new pathpoint DR coordinates are stored, a smoothing process is triggered, and the smoothed DR coordinates are stored in the smoothed cache.

[0050] In an embodiment of the present invention, during the target tracking process, the relative position in the ego vehicle coordinate system obtained by the perception module is converted to the ego vehicle's current DR coordinate system. After obtaining the DR coordinates of the target's relative position, they are preferably arranged in a queue in the time order of their formation, and are preferentially stored in the smoothed cache. After the smoothed cache is filled, they are stored in the cache to be smoothed.

[0051] Among them, when tracking starts, after the DR coordinates of the relative position of the target are obtained, they are stored in the smoothed cache after smoothing to form a smoothed path. After the smoothed cache is filled, the DR coordinates of the relative positions of other targets are stored in the to-be-smoothed cache for processing. In the subsequent tracking process, the DR coordinates of the target are obtained and stored in the to-be-smoothed cache, and processed through smoothing triggering. After smoothing, they are stored in the smoothed cache to form a smoothed path.

[0052] In the embodiment of the present invention, preferably, the size of the buffer to be smoothed is fixed. After it is filled, each new DR coordinate will trigger a smoothing operation, and the first coordinate in the buffer to be smoothed will be stored in the smoothed buffer. There is no upper limit on the smoothed buffer, and it only needs to ensure that the number is greater than the minimum number.

[0053] See also Figure 4 As shown, each small rectangular box represents the target DR coordinates recorded, which are arranged in order according to the queue. During the processing, the capacity C is filled first. filt Smoothed cache B filt , and then load it into the buffer B to be smoothed raw And always ensure the actual B raw Capacity m and C raw The same, that is, whenever B is loaded raw The actual number m is C raw +1, trigger a smoothing, and B raw The first element T in n+1dr After smoothing, put it into B filt middle;

[0054] Among them, the smoothing calculation method, such as the smoothing method using weighted mean filtering, is as follows:

[0055]

[0056] Since the ego vehicle is generally at a certain distance from the target vehicle when tracking the target, at this time, the above-mentioned tracking path will not be formed based on the DR coordinates for tracking. Therefore, in an embodiment of the present invention, when the target tracking is initialized, that is, when the tracking starts, the control module forms an interpolation path based on the DR coordinates or a relative path based on the vehicle coordinates according to the current position of the ego vehicle and the starting position of the target through the interpolation algorithm, and stores it in the smoothed cache after smoothing, so as to be spliced ​​with the tracking path formed based on the DR coordinates during the target tracking process to ensure smooth tracking. The above-mentioned interpolation operation only needs to be triggered once at the beginning.

[0057] In practical applications, the path based on DR coordinates ultimately needs to be converted into the vehicle coordinate system and given to the control module for use. In order to avoid meaningless conversion between coordinate systems, preferably, in an embodiment of the present invention, a linear interpolation path of the vehicle coordinate system is directly generated.

[0058] See also Figure 5 As shown, an embodiment of the present invention provides a target tracking path generation device, comprising:

[0059] The DR coordinate conversion module 11 is used to obtain the relative position of the target vehicle in the current vehicle coordinate system and convert the relative position to the current DR coordinate system of the vehicle;

[0060] A coordinate updating module 12 is configured to update a tracking path under DR coordinates according to the conversion result; the tracking path includes a smoothed path stored in a smoothed buffer and a path to be smoothed stored in a buffer to be smoothed;

[0061] a smoothing processing module 13 configured to, after the number of path point DR coordinates in the buffer to be smoothed reaches a capacity threshold, smooth the first path point DR coordinate in the buffer to be smoothed when a new path point DR coordinate is stored, and then store the smoothed path point DR coordinate;

[0062] The tracking path generation module 14 is configured to convert the smoothed path in the DR coordinate system into the ego vehicle coordinate system according to the current DR coordinate system of the ego vehicle to form a tracking path in the ego vehicle coordinate system.

[0063] The coordinate updating module is further used for:

[0064] The DR coordinates of the relative position of the target are obtained as the conversion results, and the conversion results are arranged in a queue in chronological order and stored in the smoothed cache first. After the smoothed cache is filled, it is stored in the cache to be smoothed to complete the update operation of the tracking path under the DR coordinates.

[0065] The path interpolation module 12 is used to generate an interpolated path based on the current position of the vehicle and the starting position of the target during target tracking by the control module through an interpolation algorithm according to the vehicle coordinates. The interpolated path is stored in the smoothed buffer for splicing with the tracking path obtained during the target tracking process.

[0066] The smoothing triggering module 15 is configured to trigger the smoothing processing module to perform a smoothing process when it is determined that the number of the path point DR coordinates in the buffer to be smoothed reaches a capacity threshold and new path point DR coordinates are stored.

[0067] In the embodiment of the present invention, the coordinates of the current recursive coordinate system of the vehicle are completely dependent on the coordinates calculated by the inertial navigation sensor, that is, the DR coordinates are P dr (x dr ,y dr ,θ dr ), the target relative coordinate calculated by the perception module is T r (x r ,y r ), according to the coordinate transformation, the DR coordinate T of the target in the recursive coordinate system can be calculated dr (x T dr ,y T dr ,θ T dr ):

[0068]

[0069]

[0070]

[0071] Where (x, y, θ) represents the horizontal and vertical coordinates and angles of the vehicle in a certain coordinate system, the subscripts r and dr represent the vehicle reference system and the ground reference system, respectively, and the superscript T represents the target position.

[0072] Unlike global coordinates, the DR coordinate system accumulates over time, and there will be a relatively large cumulative error compared to the real position, so it cannot be used continuously for a long time. However, the relative deviation between well-calibrated DR coordinates does not accumulate over time. Therefore, in scenarios with shorter distances, the relative relationship between DR coordinates is basically the same as the relative relationship between real coordinates, and therefore the relative position relationship relative to the ego vehicle is also basically similar. In the target tracking task, the ego vehicle is concerned with the relative relationship of each path point relative to itself. This "generate and use" approach reduces the impact of the inherent cumulative error of inertial navigation. Figure 2 As shown in Figure 2, the relationship between the DR coordinates of the ego vehicle and the target vehicle and the ego vehicle coordinates is as follows:

[0073] Among them, O dr X dr Y dr Indicates the DR coordinate system, X r 、Y r Indicates the horizontal and vertical coordinate directions of the vehicle coordinate system, when recording a series of DR coordinates of the target in the recursive coordinate system T dr (x T dr ,y T dr ,θ T dr ) can be calculated based on the vehicle coordinate P dr (x dr ,y dr ,θ dr ), each T dr Restore to the vehicle coordinate system and obtain the relative coordinate T r (x r ,y r ) is transmitted to the control module to restore and track the target path.

[0074] Specifically, a series of T r Convert T to DR coordinate system dr Save and then convert to relative coordinates T rIn this way, when controlling the tracking path, we only need to pay attention to the path information of the target vehicle relative to the vehicle coordinate system.

[0075] If the relative coordinate T is not r Convert T to DR coordinate system dr To store, then for a series of relative coordinates T recorded when the vehicle is constantly moving r , which does not have a stable meaning. Therefore, in the embodiment of the present invention, the relative coordinate T r Convert T to DR coordinate system dr Storage is performed to ensure the stability of coordinates.

[0076] During the target tracking process, the target position information obtained by the perception module in the ego-vehicle coordinate system is converted into the ego-vehicle's current DR coordinate system to form the corresponding DR coordinates, so as to update and store the stored tracking path. By utilizing the characteristics of recursive coordinates that will not change suddenly and have very small errors in a short period of time, the task of tracking the target is generally maintained within a relatively short visual distance and is not sensitive to cumulative errors. Therefore, the advantages of the global coordinate path generation method can be maintained, that is, the target path is accurately restored, without the problem of positioning mutation that is difficult to avoid in the global coordinate path generation method.

[0077] When recording the target DR coordinates T dr When the vehicle is in motion, sudden braking, sudden steering and other actions are inevitable, which will cause the DR coordinates of the vehicle P dr There will be a momentary large fluctuation. At the same time, due to the limitation of the sensor or perception module on the tracking effect of the target, there will often be an estimated deviation of the target's relative position in scenes such as the target turning or making a U-turn (for example, when the target turns, the tracking point jumps from the rear of the target vehicle to the side of the target vehicle, etc.). In order to ensure a better tracking effect, it is necessary to smooth the recorded target DR coordinates.

[0078] In addition, due to the inherent characteristics of the control, the vehicle has a strong dependence on the path to be tracked not to have sudden jitters. Therefore, when smoothing the path, it is necessary to ensure that the path that the vehicle is about to traverse is stable and will not change suddenly due to smoothing, and on the other hand, it is necessary to ensure that the newly recorded target DR coordinates are all smoothed. Therefore, the embodiment of the present invention proposes two buffer areas for dynamic smoothing, namely a stable buffer area (smoothed cache) and a buffer area to be smoothed, which together constitute the tracking path of the vehicle, thereby ensuring that the path that the vehicle is about to traverse is stable and will not change suddenly, and at the same time ensuring that the newly recorded target DR coordinates are all smoothed. Due to the existence of the buffer to be smoothed, the recorded target positions are smoothed in order by weighted mean filtering that takes into account the previous and next data, so that the fluctuation of the path is reduced and a better tracking effect is achieved. The schematic diagram of the smoothed path is shown as follows. Figure 3 shown.

[0079] In order to achieve a smooth walking path of the ego vehicle during the tracking process, in an embodiment of the present invention, the data amount of the target DR coordinates stored in the smoothed cache only increases, and the existing members do not change. When the target DR coordinates in the cache to be smoothed are triggered to be smoothed, they are stored in the smoothed cache, thereby ensuring that the path that the ego vehicle (autonomous driving vehicle) is about to walk will not suddenly change.

[0080] Therefore, in an embodiment of the present invention, the target tracking path generation device based on the recursive coordinate system includes a smoothing trigger module, which is connected to the smoothing processing module and is used to trigger the smoothing processing module to perform a smoothing process when it is determined that the number of path point DR coordinates in the cache to be smoothed reaches a capacity threshold and new path point DR coordinates are stored.

[0081] In an embodiment of the present invention, the target tracking path generation device based on the recursive coordinate system, during the target tracking process, converts the relative position in the ego-vehicle coordinate system obtained by the perception module to the ego-vehicle's current DR coordinate system through the DR coordinate conversion module, and obtains the DR coordinates of the relative position of the target. Preferably, it also arranges the DR coordinates in a queue according to the time sequence of their formation through its coordinate update module, and stores them in the smoothed cache first, and then stores them in the cache to be smoothed after the smoothed cache is filled.

[0082] Among them, when tracking starts, after the DR coordinates of the relative position of the target are obtained, they are stored in the smoothed cache after smoothing to form a smoothed path. After the smoothed cache is filled, the DR coordinates of the relative positions of other targets are stored in the to-be-smoothed cache for processing. In the subsequent tracking process, the DR coordinates of the target are obtained and stored in the to-be-smoothed cache, and processed through smoothing triggering. After smoothing, they are stored in the smoothed cache to form a smoothed path.

[0083] In the embodiment of the present invention, preferably, the size of the buffer to be smoothed is fixed. After it is filled, each new DR coordinate will trigger a smoothing operation, and the first coordinate in the buffer to be smoothed will be stored in the smoothed buffer. There is no upper limit on the smoothed buffer, and it only needs to ensure that the number is greater than the minimum number.

[0084] See also Figure 4 As shown, each small rectangular box represents the target DR coordinates recorded, which are arranged in order according to the queue. During the processing, the capacity C is filled first. filt Smoothed cache B filt , and then load it into the buffer B to be smoothed raw And always ensure the actual B raw Capacity m and C raw The same, that is, whenever B is loaded raw The actual number m is Craw +1, trigger a smoothing, and B raw The first element T in n+1dr After smoothing, put it into B filt middle;

[0085] Among them, the smoothing calculation method, such as the smoothing method using weighted mean filtering, is as follows:

[0086]

[0087] Since the ego vehicle is generally at a certain distance from the target vehicle when it starts to track the target vehicle, at this time, the above-mentioned tracking path will not be formed based on the DR coordinates for tracking. Therefore, in an embodiment of the present invention, the target tracking path generation device based on the recursive coordinate system includes a path interpolation module, which is used to form an interpolation path based on DR coordinates or a relative path based on vehicle coordinates according to the current position of the ego vehicle and the starting position of the target through an interpolation algorithm when the target tracking is initialized, and the interpolation path is stored in the smoothed cache after smoothing, so as to be spliced ​​with the tracking path formed based on DR coordinates during the target tracking process to ensure smooth tracking. The above-mentioned interpolation operation only needs to be triggered once at the beginning.

[0088] In practical applications, the path based on DR coordinates ultimately needs to be converted into the vehicle coordinate system and given to the control module for use. In order to avoid meaningless conversion between coordinate systems, preferably, an embodiment of the present invention directly generates a linear interpolation path in the vehicle coordinate system.

[0089] In the embodiment of the present invention, the number of target DR coordinates stored in the buffer to be smoothed always remains constant, and the smoothed buffer B filt The amount of data only increases, and the existing members do not change, thereby ensuring that the vehicle's walking path is smooth during tracking.

[0090] An embodiment of the present invention also provides an electronic device, comprising at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the target tracking path generation method.

[0091] In an embodiment of the present invention, the relative position of the target is converted into a dead reckoning (DR) coordinate system and the target position information is stored in the DR coordinate system. Since the recursive coordinate system has the characteristics of no sudden change and very small error in a short period of time, and the task of tracking the target is generally maintained within a relatively short visual distance and is not sensitive to cumulative errors, the present invention can maintain the advantages of the global coordinate path generation method, that is, accurately restore the target path, without the problem of positioning sudden change that is difficult to avoid in the global coordinate path generation method.

[0092] To address the target fluctuation problem, an embodiment of the present invention proposes a two-level cache dynamic smoothing solution. Two cache areas are used to store the smoothed path and the path to be smoothed, respectively. The relative position of the target is preferentially stored in the smoothed cache. When it is full, it is stored in the cache to be smoothed. A filtering algorithm is used in real time to process the path points in the cache to be smoothed and add them to the smoothed cache. This ensures the dynamic smoothing effect of the path and ensures that the path section that the vehicle is about to track (the smoothed cache) is not changed due to the smoothing effect, so that the vehicle can track stably.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A target tracking path generation method, characterized in that: Including steps: Get the current relative position of the target vehicle in the vehicle coordinate system; Convert the relative position to the current DR coordinate system of the vehicle, and update the tracking path in the DR coordinate system according to the conversion result; the tracking path includes the smoothed path stored in the smoothed buffer and the path to be smoothed stored in the buffer to be smoothed; After the number of path point DR coordinates in the buffer to be smoothed reaches a capacity threshold, when new path point DR coordinates are stored, the path point DR coordinate that first enters the buffer to be smoothed is smoothed and then stored in the smoothed path; The smoothed path in the DR coordinate is converted to the vehicle coordinate system according to the current DR coordinate of the vehicle to form a tracking path in the vehicle coordinate system.

2. The method according to claim 1, characterized in that The updating of the tracking path in the DR coordinate according to the conversion result includes: The DR coordinates of the relative position of the target are obtained as the conversion results, and the conversion results are arranged in a queue in chronological order and stored in the smoothed cache first. After the smoothed cache is filled, it is stored in the cache to be smoothed to complete the update operation of the tracking path under the DR coordinates.

3. The method according to claim 1, characterized in that When target tracking is initialized, the control module forms an interpolation path based on the current position of the vehicle and the starting position of the target, and according to the vehicle coordinates through an interpolation algorithm, and stores it in the smoothed cache to be spliced ​​with the tracking path obtained during the target tracking process.

4. The method according to claim 3, characterized in that The interpolation path is an interpolation path in the DR coordinate system of the vehicle, or an interpolation path in the relative coordinate system of the vehicle.

5. A target tracking path generation device, characterized in that: include: DR coordinate conversion module, used to obtain the relative position of the target vehicle in the ego vehicle coordinate system; Convert the relative position to the current DR coordinate system of the vehicle; A coordinate updating module is used to update the tracking path under the DR coordinate according to the conversion result; the tracking path includes the smoothed path stored in the smoothed buffer and the path to be smoothed stored in the buffer to be smoothed; a smoothing processing module configured to, after the number of path point DR coordinates in the buffer to be smoothed reaches a capacity threshold, smooth the first path point DR coordinate in the buffer to be smoothed when a new path point DR coordinate is stored, and then store the smoothed path point DR coordinate; The tracking path generation module is used to convert the smoothed path in the DR coordinate system into the ego vehicle coordinate system according to the current DR coordinate system of the ego vehicle to form a tracking path in the ego vehicle coordinate system.

6. The device according to claim 5, characterized in that The coordinate updating module is further used for: The DR coordinates of the relative position of the target are obtained as the conversion results, and the conversion results are arranged in a queue in chronological order and stored in the smoothed cache first. After the smoothed cache is filled, it is stored in the cache to be smoothed to complete the update operation of the tracking path under the DR coordinates.

7. The device according to claim 5, characterized in that include: The path interpolation module is used to control the current position of the vehicle and the starting position of the target during target tracking. The control module forms an interpolated path through an interpolation algorithm based on the vehicle coordinates and stores it in the smoothed cache to be spliced ​​with the tracking path obtained during the target tracking process.

8. The device according to claim 7, characterized in that The interpolation path is an interpolation path in the DR coordinate system of the vehicle, or an interpolation path in the relative coordinate system of the vehicle.

9. The device according to claim 5, characterized in that include: The smoothing triggering module is used to determine that the number of path point DR coordinates in the buffer to be smoothed reaches a capacity threshold and new path point DR coordinates are stored, thereby triggering the smoothing processing module to perform a smoothing process.

10. An electronic device, characterized in that: The invention comprises at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the target tracking path generation method according to any one of claims 1 to 4.

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