Procedure for convoy vehicle management

Abstract

A method for controlling a plurality of vehicles to operate the plurality of vehicles in a convoy, the method comprising: within a lead vehicle selected from among several vehicles: monitoring a respective actual position of each of the plurality of vehicles other than the lead vehicle through vehicle-to-vehicle short-range communication based on data from a respective global positioning device in each of the plurality of vehicles other than the lead vehicle; Monitoring the operation of the column at a column speed; Determining a forward tolerance of a desired column shell based on the monitored operation of the column; Defining the desired platoon envelope based on the respective actual position of each of the plurality of vehicles other than the lead vehicle and the forward tolerance; Monitoring an operating environment around the column; Determining a violation of the desired column shell based on the operating environment; and selecting a respective commanded vehicle position for each of the plurality of vehicles based on the violation of the desired platoon envelope; Transmitting each corresponding commanded vehicle position to the respective one of the plurality of vehicles that is not the lead vehicle; and Operating each respective one of the plurality of vehicles other than the lead vehicle based on the respective commanded vehicle position.

Description

TECHNICAL FIELD

[0001] This disclosure relates to a method for controlling multiple vehicles to operate the multiple vehicles in a convoy. BACKGROUND

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] Driving in congested, densely populated urban areas requires significant driver attention. Maneuvering a vehicle in such areas requires the driver's attention to traffic flow, road conditions, signage, traffic signals, and pedestrian traffic. Time spent in traffic reduces the time available to the driver for other personal and work-related activities.

[0004] Autonomous or semi-autonomous control methods are known in which a vehicle is equipped with devices that can locate the vehicle relative to the road and other traffic on the road, and control methods are used to enhance or replace driver control of the vehicle. Such methods are described, for example, in US 2006 / 0161341 A1, WO 2004 / 077378 A1, and in the paper by Antonelli, G. et al., "Kinematic Control of Platoons of Autonomous Vehicles," IEEE Transactions on Robotics, Vol. 22, No. 6; December 2006, pp. 1285-1292.

[0005] According to WO 2004 / 077 378 A1, the vehicles communicate with each other directly over distances of several kilometers.

[0006] The use of vehicles optimized for urban situations in combination with control methods using autonomous control is desirable.

[0007] The object of the invention is to provide an energy-efficient method for controlling several vehicles in a convoy. SUMMARY

[0008] The problem is solved by a method having the features of claim 1. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] One or more embodiments will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 illustrates an exemplary host vehicle in traffic with another vehicle, the host vehicle including a number of devices useful for controlling the host vehicle, in accordance with the present disclosure; Fig. 2 illustrates an exemplary host vehicle on a road section using a number of different inputs that may be used to locate the vehicle, in accordance with the present disclosure; Fig. 3 illustrates an exemplary GPS coordinate monitored by a GPS device according to the present disclosure; Fig. 4 illustrates an exemplary determination of an angle to a signal relative to the longitudinal axis of the vehicle according to the present disclosure; Fig. 5 illustrates an exemplary analysis of the lateral position and angular orientation of a vehicle relative to a lane based on camera information in accordance with the present disclosure; Fig. 6-8 demonstrate an exemplary method for determining a location of a vehicle in accordance with the present disclosure; Fig. 6 illustrates an exemplary GPS coordinate monitored by a GPS device in combination with 3D map data for the GPS coordinate; Fig.7 represents the identification of a lateral position and an angular orientation with respect to the lane; Fig. 8 illustrates an exemplary method for using a directional signal, such as a radio signal from a known source or a radar signal return, to locate the position of a vehicle; Fig. 9 illustrates exemplary target tracking information according to the present disclosure; Fig. 10 illustrates information from a GPS device, including a nominal position, a GPS error margin, and a determined actual position defining a GPS offset error, according to the present disclosure; Fig. 11 illustrates a host vehicle and two targets all monitoring nominal GPS positions and resulting GPS offset errors in accordance with the present disclosure; Fig.12 illustrates vehicles employing example methods for controlling vehicle operation in accordance with the present disclosure; Fig. 13 illustrates an exemplary vehicle and a desired wrap around the vehicle in accordance with the present disclosure; Fig. 14 describes an exemplary method for formulating a minimum desired distance in front of a vehicle in accordance with the present disclosure; Fig. 15 illustrates the operation of an exemplary column according to the present disclosure; Fig. 16 schematically illustrates an exemplary in-vehicle platoon control system according to the present disclosure; Fig. 17 illustrates an exemplary column formation according to the present disclosure; Fig. 18 illustrates exemplary column roles and defined positions according to the present disclosure; Fig.19 illustrates an exemplary column, a number of defined positions within the column, and a number of illustrative states for the illustrated positions in accordance with the present disclosure; Fig. 20 illustrates exemplary decisions made when creating a column, according to the present disclosure; Fig. 21 graphically illustrates exemplary fuel efficiency savings realized during drafting as a function of separation distance in accordance with the present disclosure; Fig. 22 graphically depicts exemplary fuel consumption rates as a function of position within a platoon and vehicle separation distances in accordance with the present disclosure; Fig.23 graphically depicts exemplary fuel consumption as a function of vehicle separation distances and a fraction of the square root of the frontal area in accordance with the present disclosure; Fig. 24 graphically depicts fuel consumption as a function of vehicle spacing versus vehicle length in accordance with the present disclosure; Fig. 25 graphically illustrates a method for selecting a desired distance from a follower vehicle to a lead vehicle in accordance with the present disclosure; Fig. 26 graphically illustrates the use of an exemplary fail-safe speed profile in accordance with the present disclosure; Fig. 27 illustrates the function of an exemplary desired envelope around a convoy of vehicles according to the present disclosure; Fig.28 illustrates an exemplary process for a vehicle to join a platoon in accordance with the present disclosure; Fig. 29 illustrates an exemplary process by which positions within a formation may be reassigned, in accordance with the present disclosure; Fig. 30 illustrates an exemplary process by which a following vehicle may request a position change, in accordance with the present disclosure; Fig. 31 illustrates an exemplary process by which a following vehicle may request to leave a platoon, in accordance with the present disclosure; Fig. 32 illustrates an exemplary process by which a lead vehicle may relinquish leadership of a platoon and assume a flowing vehicle status, in accordance with the present disclosure; Fig. 33 and Fig.34 illustrates an exemplary process by which a follower vehicle may request a change of formation lead and responses that may occur based on the lead vehicle's response, in accordance with the present disclosure; Fig. 33 describes an example reaction if the request is refused; Fig. 34 describes an example response if the request is granted; Fig. 35 illustrates an exemplary response when communication is lost between a lead vehicle and follower vehicles in a formation, in accordance with the present disclosure; Fig. 36 illustrates an exemplary response when a lead vehicle decides to disband a platoon, in accordance with the present disclosure; Fig.37 illustrates an exemplary connectivity map describing methods for accomplishing enhanced connectivity between members of a platoon, in accordance with the present disclosure; Fig. 38 illustrates an exemplary process for managing communication problems within a platoon in accordance with the present disclosure; Fig. 39 illustrates an exemplary projection of a path for a platoon to follow in accordance with the present disclosure; Fig. 40 schematically illustrates the function of an autonomous system architecture diagram, including the operation of a remotely operated portable navigation device that transmits commands to the vehicle control systems, in accordance with the present disclosure; Fig.41 illustrates exemplary speed profile data that may be used to execute a deceleration or stopping maneuver, in accordance with the present disclosure; Fig. 42 illustrates an exemplary method for determining the length of a desired column shell in accordance with the present disclosure; and Fig. 43 illustrates an exemplary method for determining the width of a desired column shell in accordance with the present disclosure. DETAILED DESCRIPTION

[0010] In the drawings, in which the illustrations are only for the purpose of explaining certain exemplary embodiments and not for the purpose of limiting the same, Fig.1 illustrates an exemplary host vehicle in communication with another vehicle, the host vehicle including a number of devices useful for controlling the host vehicle, in accordance with the present disclosure. The host vehicle 10 travels near a target vehicle 20. The host vehicle 10 may include exemplary sensor devices, including a radar system 30 and a camera system 40. In addition, the host vehicle 10 receives signals from a remote wireless communication system 50 and remote satellite system 60. A V2X communication device 35A is illustrated that enables the host vehicle 10 to communicate with infrastructure, such as a remote wireless communication system 50, or other vehicles. A V2X communication device 35B is illustrated on the target vehicle 20 that enables communication between the target vehicle 20 and the host vehicle 10, or V2V communication.V2X communication can be defined as short-range wireless communication between a vehicle and a remotely located communication device for the purpose of providing information regarding the operating environment around the vehicle. V2X communication includes V2V communication between two vehicles and V2I communication between a vehicle and a traffic infrastructure device or system. The host vehicle 10 monitors and processes available information from the aforementioned systems, including information about the target vehicle 20, the road surface being traveled on, and other information available from the remote systems, for the purpose of facilitating control of the host vehicle 10.

[0011] Sensor data and other information can be used in various applications to implement autonomous or semi-autonomous control of a vehicle. For example, adaptive cruise control (ACC) is well known, whereby a vehicle monitors a distance to a target vehicle and controls the vehicle speed to maintain a minimum distance to the target vehicle. Lane keeping methods use available information to predict and react when a vehicle unexpectedly crosses a lane boundary. Object tracking methods monitor objects in the vehicle's operating environment, for example, on a projected path ahead of the vehicle, and facilitate reactions to the object trajectories. Vehicle lateral control is well known, whereby information regarding a projected clear path, a lane keeping boundary, or a potential for a collision is used to steer the vehicle.Vehicle lateral control can be used to implement lane changes, and sensor data can be used to check for lane change availability. Collision avoidance systems or collision preparation systems are known, where information is monitored and used to predict a probability of a collision. Actions are taken in the event that the predicted probability of a collision exceeds a threshold. Many forms of autonomous and semi-autonomous control are known, and the disclosure is not intended to be limited to the specific exemplary embodiments described herein.

[0012] Many information sources can be used in coordination to control a carrier vehicle. Fig.2 illustrates an exemplary host vehicle on a road section using a number of different inputs that can be used to locate the vehicle, in accordance with the present disclosure. The host vehicle 105 is traveling on a road surface 100 in a lane 110 defined by lane markings 115A and 115B. The host vehicle 105 is similar to the vehicle 10 and also includes a GPS device 135 in communication with a global positioning service that enables an estimation of the current vehicle position with respect to a 3D map database calibrated to coordinates provided by the GPS device 135. One of ordinary skill in the art will recognize that information from the GPS device includes GPS error. Known GPS systems provide a data stream of coordinates at a sampling rate ranging from approximately 1-20 Hz.The host vehicle 105 also monitors radar and camera information as described in . Fig.1. Also shown is a cell tower 125. Information via a wireless network from such a cell tower may be used as information for the host vehicle 105. Furthermore, signals from the cell tower 125, even if otherwise unrelated to the operation of the vehicle 105, may be used to provide a tracking angle to the known location of the tower. Such a known location may be determined according to reference information, such as that contained in a 3D map database, or may be located by repeatedly passing a detectable signal, such as a radio signal transmitting at a specific AM frequency or in a specific FM band. Alternative signals in the ISM band and / or DSRC band (5.9 GHz) frequencies may also be used for this purpose. Radar returns may be used to locate a vehicle.For example, a wayfinding sign 120 is illustrated. In methods similar to those described above for locating the vehicle's location relative to a cell tower, radar returns from the example wayfinding sign 120 may be used to refine an estimate of the vehicle's location on the road surface 100. A camera view or analysis of camera images may also be used to locate the vehicle's location. For example, camera images of the wayfinding sign 120, lane markings 115A and 115B, or the presence of an exit 130, combined with information regarding the location of these features relative to the road surface 100, enable an improved estimate of the vehicle's location on the road surface 100.Other exemplary methods for locating the vehicle location on a road surface are contemplated (including, for example, LIDAR devices or ultrasonic devices), and the disclosure is not intended to be limited to the specific embodiments described herein.

[0013] Fig.3 illustrates an exemplary GPS coordinate monitored by a GPS device according to the present disclosure. A GPS device returns information from a remote satellite system describing a location of the GPS device according to a global coordinate system (latitude, longitude, elevation). The returned information may be described as a nominal location. However, as described above, GPS data is not accurate and includes GPS error. The actual location of the GPS device may be anywhere within a range defined by the nominal location and the GPS error. When the distance between vehicles is calculated using GPS position differencing, most GPS errors cancel out for vehicles in close proximity (e.g., within 500 m), and accurate relative distances can often be obtained.

[0014] Fig.Figure 4 illustrates an exemplary determination of an angle to a signal relative to the longitudinal axis of the vehicle according to the present disclosure. Signals received by vehicle 10 may include radar signals returned from detected objects or signals monitored by independent transmitters, such as radio or wireless towers. As shown in Fig. As described in Section 4, analysis of received signals can provide an angle of the signal relative to the vehicle's longitudinal axis (θ). Some signals, such as radar returns, can also provide a distance from a target object from which the signal was returned.

[0015] Fig.5 illustrates an exemplary analysis of the lateral position and angular orientation of a vehicle with respect to a lane based on camera information according to the present disclosure. The vehicle 10 is illustrated with a camera device 40, traveling in a lane 110. A field of view may be described by an area represented in a visual image. As can be seen and as shown in Fig.5, boundaries of a field of view that can be analyzed by a visual image can be described as an angular range extending outward from the camera capturing the image. Using image recognition techniques, lane markings, road features, landmarks, other vehicles on the road, or other recognizable images can be used to estimate a vehicle position and orientation relative to the lane 110. From the analysis of visual images, a lateral position within the lane 110 can be estimated, for example, according to distances a and b from the lane markings. Likewise, an orientation of the vehicle 10 within the lane can be estimated and described as an angle φ.

[0016] Information monitored within a vehicle can be used to determine a vehicle's location relative to 3D map data. Fig.6-8 demonstrate an exemplary method for determining a vehicle location according to the present disclosure. GPS data may be used in coordination with 3D map data to approximate a vehicle location relative to a road surface. Fig. Figure 6 illustrates an example GPS coordinate monitored by a GPS device in combination with 3D map data for the GPS coordinate. As shown in Fig. 3, a nominal location identified by a GPS device can be used to describe an area in which the device may be located. In Fig.6, the nominal location combined with a GPS error yields an area where the GPS device can be located in the vehicle, or a range of possible vehicle locations. The coordinates of the nominal location can be coordinated with corresponding coordinates in 3D map data, and the range of possible vehicle locations can be projected onto a map.

[0017] Within the range of possible vehicle locations made possible by monitoring GPS data, other information can be used to determine the location of the vehicle within the Fig. 6 described range of possible vehicle locations. Image recognition methods can be used, for example, as in Fig. 5 to identify features on the road in front of the vehicle. Fig.Figure 7 illustrates the identification of a lateral position and angular orientation relative to the lane. This information can be used to place the vehicle within the range of possible vehicle locations. Furthermore, lane markings can be examined, for example, using a dashed line versus a solid line, to identify one lane from among the possible lanes within the possible vehicle locations. Furthermore, any recognizable features identified within the camera data can be used to determine a location.Recognizable features that can be identified and used in conjunction with a 3D map database to determine location include the occurrence of an intersection, exit or on-ramp, the encounter of a bridge or overpass, the approach of an identifiable building, or any other similar details contained within the 3D map data.

[0018] Procedures that Fig. 7 can adequately locate the vehicle or can specify a range of locations or alternative locations where the vehicle may be located. Fig. Figure 8 illustrates an exemplary method for using a directional signal, such as a radio signal from a known source or a radar signal return, to locate the position of a vehicle. In the exemplary determination shown in Fig.7, a range of possible vehicle locations was determined. A directional signal from the radio tower shown allows an intersection point between the range of positions within the lane, which is shown in Fig. 7, and the direction to the radio tower to determine a detected location of the vehicle. In this way, a combination of information sources can be used to determine a detected location of a vehicle with reasonable accuracy.

[0019] The Fig.The method illustrated in Figure 8 is an exemplary method for determining a location of a vehicle, wherein an approximate location derived from a GPS coordinate and a digital map database is refined first with visual data or radar data and then with a radio or other wireless directional signal. It will be appreciated that a number of methods for locating the position of a vehicle may equally be used to determine the location of the vehicle to enable the methods described herein. In combination with a GPS signal, for example, visual data or radar data in combination with digital map information, multiple radio, radar, or similar signals derived from known sources may be used to locate a position of a vehicle.In another example, a local communications network could include a local correction factor specific to that geographic location to correct the position determined by GPS coordinates. The disclosure is not intended to be limited to the specific examples described herein.

[0020] Fig.Figures 6-8 demonstrate an exemplary method for determining a vehicle's location. One skilled in the art will recognize that a number of methods are known for determining or triangulating a vehicle's position. For example, radar returns or radio returns from two known objects can be used to triangulate a vehicle's position on a map.Once a position is determined at any time, another method could determine an estimated change in the vehicle's position by estimating the vehicle's motion, for example, assuming travel along a current road based on a monitored vehicle speed, by using a gyroscopic or accelerometer device, or based on determining a GPS error margin by comparing the last determined location with the nominal GPS position at that time and assuming the GPS error margin is similar for some period of time. One of ordinary skill in the art will recognize that many such example methods are known, and the disclosure is not intended to be limited to the example methods described herein.Furthermore, an exemplary infrastructure device includes a GPS differential device, which may be located, for example, along roads, may communicate with passing vehicles, and may provide a GPS offset value for the vehicles for a localized area. In such a known device, a nominal GPS location for the device is compared with a fixed, known position for the device, and the difference yields a GPS offset value that can be used by vehicles operating in the area. By using such a device, sensor readings and calculations for triangulating a host vehicle's location are unnecessary.

[0021] The use of methods to determine a location of a lead vehicle and coordinate a number of vehicles based on the operation of the lead vehicle can be very beneficial for streamlining within a densely populated or urban area.

[0022] Object tracking is a process in which a host vehicle uses information such as radar returns to determine successive relative positions of a target object with respect to the host vehicle. Fig.9 illustrates exemplary target tracking information according to the present disclosure. Positions for a first object Q1 and a second object O2 are described at successive times T1-T3. The three plotted positions of object O1 describe an object that is progressively getting closer to the host vehicle. Such a trajectory can be used in a number of ways by the host vehicle, for example, by comparing a distance to O1 with a minimum allowable distance or by determining a probability of a collision between O1 and the host vehicle.

[0023] Fig.10 illustrates information from a GPS device, including a nominal position, a GPS error margin, and a determined actual position defining a GPS offset error, according to the present disclosure. As described above, a nominal position is monitored by a GPS device. Based on an error inherent in GPS technology, some inaccuracy in the GPS determination is inherent in the nominal location, creating a range of possible positions relative to the nominal position. Through methods such as the exemplary methods described above, an actual or determined location of the GPS device may be determined. By comparing the actual or determined location of the GPS device to the nominal position, a GPS offset error may be calculated as a vector offset from the nominal position.

[0024] Errors in sensing devices may be randomly offset in changing directions and distances, with scattered results indicating poor accuracy; or errors may be consistently offset in a particular direction and distance, with closely grouped results indicating good accuracy. One skilled in the art of GPS devices will recognize that an error in a GPS device will usually have good accuracy, with iterative results over a range and at close time intervals having closely grouped results with similar GPS error offsets. Likewise, multiple devices operating in close proximity to each other and monitoring nominal position information at substantially the same time will usually experience similar GPS error offsets.

[0025] Fig.Figure 11 illustrates a host vehicle and two target objects, each monitoring nominal GPS positions, and resulting GPS offset errors according to the present disclosure. As described above, GPS offset errors in multiple objects monitoring nominal positions at the same time typically have the same or similar GPS offset errors. Nominal positions for the host vehicle and for target objects O1 and O2 are described, for example, describing each of the nominal positions as if there were three GPS devices, one in the host vehicle and one in each of the target objects. An actual position of the host vehicle is determined, and a GPS offset error can be determined for the host vehicle.Based on the tendency of GPS devices to provide information with good accuracy and on the basis of an accurate estimation of the actual location of the host vehicle, the correlation of the three nominal locations creates an ability to determine stated actual positions for O1 and O2 with high accuracy.

[0026] Methods are known to use information regarding the driving environment around a vehicle to autonomously or semi-autonomously control the relative location of the vehicle with respect to a lane and with respect to other vehicles. Fig.12 illustrates vehicles using example methods to control vehicle operation in accordance with the present disclosure. A vehicle 310, a vehicle 320, and a vehicle 330 travel in a lane 300 defined by lane markings 305A and 305B. The vehicle 320 uses a radar signal to determine a distance to the vehicle 310, useful, for example, in an ACC application, and the vehicle 320 also uses known methods to establish an estimated position within the lane and determine lane departure boundaries 325A and 325B. The vehicle 330 also monitors a distance to the vehicle 320, in this example case using an ultrasonic signal. The vehicle 330 may be manually operated, with the driver, for example, steering the vehicle and using distance information to maintain a desired following distance behind the vehicle 320.

[0027] An individual vehicle moves according to its own direction and does not attempt to coordinate its movement with other vehicles. A formation is a specific arrangement of two or more vehicles traveling together in a coordinated manner. The general pattern of a formation is consistent over extended periods of time (based on navigation objectives and situations), but the specific details of the pattern can be adjusted on a moment-by-moment basis based on external factors and the driving situation. At certain times, a new formation may be put into effect due to external factors or human intervention. Each vehicle in the previous formation is assigned a unique position in the new formation. If conditions permit, each vehicle would maneuver into the correct place in the formation geometry.

[0028] Convoy driving is a method of controlling a group of vehicles using a single control scheme to control the group of vehicles in a formation. The single control scheme can be determined in a single lead vehicle. Convoy driving allows the vehicles to achieve a number of beneficial results, including increased fuel efficiency, collision risk mitigation, freeing the driver from having to focus their attention away from the road, increased efficiency in urban traffic congestion and control, and other benefits.

[0029] Each vehicle participating in the formation occupies one (and no more than one) position in the formation at a time. A position is designated as a leader, which carries specific requirements within a vehicle occupying that position, with a specific role defined for that vehicle. One or more additional follower positions may be defined within the formation. The "smoothed" position of the lead vehicle along its trajectory defines the origin and orientation of the formation space, which moves and changes orientation relative to the ground as the formation moves from one location to another.

[0030] Fig.Figure 18 illustrates exemplary platoon roles and defined positions according to the present disclosure. A lead vehicle 710 is shown located on road 700. Follower positions 1, 2, and 3 are shown as circles, defining position envelopes 720, 730, and 740 in which the vehicles may be located, and are defined relative to the position of the lead vehicle. A lateral position offset is shown, describing a lateral distance from the lead vehicle that can be defined for a vehicle in a side-by-side formation position.

[0031] This lateral offset is determined by a number of factors, including lane geometry, vehicle type, and platoon objectives or priorities. A longitudinal position offset is also shown, which describes a longitudinal distance from the lead vehicle that can be defined for a vehicle in a line-up position. This longitudinal offset is determined by a number of factors and is defined in detail throughout this disclosure.

[0032] The selection of and changes to platoon formations can be determined according to a number of factors. For example, road geometry is a consideration for platoon formation. On a single-lane road, only a single-row formation may be used, whereas on a four-lane highway, a side-by-side formation may be expediently used. In a platoon using a side-by-side formation on a four-lane highway, the formation may be expediently changed to a single-row formation when road conditions change. For example, if road construction is abruptly encountered and four lanes are reduced to two, changing the platoon to a single-row formation might be beneficial to facilitate traffic flow through the bottleneck. Upon passing the bottleneck and when traffic regains four lanes, the platoon can be changed back to a side-by-side formation.In another example, platoon goals or priorities are considerations for platoon formation. For example, if fuel efficiency is a priority for the platoon, a closely spaced row formation may be most beneficial to gain efficiencies from slipstreaming. In another example of a priority, if social interaction between occupants of different vehicles is a priority, then a block formation with nearly identical vehicles in a row and side by side might be most beneficial to facilitate the sense of fellowship among occupants traveling together. In another example of a factor affecting formation selection, the number of vehicles in the platoon might affect formation selection. For example, if there are three vehicles in the platoon, a row formation could easily be maintained throughout the transit route.If there are fifteen vehicles in the convoy, a line formation of fifteen vehicles would be difficult to maintain through a series of traffic lights. Instead, a side-by-side formation of three columns of vehicles, each five vehicles long, might be more likely to navigate through the series of traffic lights without being unnecessarily split or temporarily disintegrated by the changing traffic lights. The same formation entering a long stretch of road without traffic lights could change the formation to a single column to take advantage of the increased fuel efficiency made possible by drafting.

[0033] According to one embodiment of the disclosure, for a vehicle to participate in a platoon formation, it must be equipped with required vehicle-to-vehicle (V2V) communication capabilities and implement at least a core subset of the formation management protocol and associated processing and maneuvering functions. Some vehicles may be capable and configured to perform any role in the formation. Others may be limited to a narrower range of roles within the formation based on vehicle equipment or driver / occupant characteristics. Participating members of the formation are called participants, or more specifically, lead vehicles and follower vehicles.

[0034] Each position within the formation has two main properties that define its overall state. The first is whether or not a vehicle is currently assigned to the position. If a vehicle is assigned to a position, the vehicle is expected to maneuver into that position as appropriate and maintain its relative location there as long as it participates in the formation. The second property is the physical layout of the area in and near the defined position. Together, these properties define a number of possible states. In an open state, no vehicle currently occupies the physical area of the position, and nothing directly prevents an attached vehicle from maneuvering into that position.There are two significant substates to the open state: available, where no vehicle is assigned to this position in the formation; and reserved, where the assigned vehicle is not currently in the position (but may assume this position given suitable conditions and sufficient time). In an impassable state, physical access to this position is prevented due to road geometry (the position would be away from the passable part of the road, over an embankment, etc.). In an intruded state, a vehicle that has not joined the formation physically occupies this position (this could be an unequipped vehicle or a vehicle in another formation). In a released state, a vehicle that was recently in the formation leaves the formation but may still be physically in or near the position.In an occupied state, a vehicle from the formation assigned to a different position instead occupies at least part of the position. In a blocked state, other vehicles in the formation are currently distributed in a manner that blocks direct maneuvering into the position; reassigning vehicles to the different positions can eliminate the blocked state. In an occupied state, the vehicle currently assigned to the position physically occupies it. A number of other states are contemplated, describing, for example, encouraged or prohibited conditions. The presence of a large truck in the platoon, for example, would limit the disposition of a vehicle directly in front of the truck, and a state describing an undesirable disposition could be defined.A dependent state could be defined, whereby family members could wish to remain in close positions within the formation, and the position of one family member could be made dependent on the position of another family member. Non-urgent preferences could be handled on an expedient basis, for example, including bubble sort logic whenever a formation changes. A person at the rear of a formation, for example, could request to move towards the front of the formation. Such a non-urgent request could be delayed until the next time the formation changes from a side-by-side formation to a line formation, at which time the requesting vehicle can move some or all of the distance towards the front of the formation, past vehicles without similar requests.The states described herein are exemplary states that may be used in a column, and the disclosure is not intended to be limited to the specific examples described herein.

[0035] Fig.19 illustrates an exemplary platoon, a number of defined positions within the platoon, and a number of illustrative states for the illustrated positions, in accordance with the present disclosure. The platoon 450 includes a lead vehicle 460, a number of defined follower positions 470, 471, 472, 473, and 474, follower vehicles 480 and 485, and an unequipped vehicle 490. According to the methods described herein, the follower positions 470-474 are defined according to the position of the lead vehicle and factors that affect the definition of the formation and resulting positions within the platoon. Under the exemplary condition, the lead vehicle 460 occupies a leader position. Follower position 1 has a position state of occupied based on the follower vehicle 480 being in follower position 1, position 470.Follower position 2, position 471, has a position state of reserved based on the follower vehicle 485 being controlled to enter follower position 2, position 471. Follower position 3, position 472, has a position state of locked. Such a locked state may be a result of any number of obstacles, identified road hazards, lane markings, or any other condition that prevents a follower vehicle from being assigned to this position. Follower position 4, position 473, has an occupied state due to a current position of vehicle 485. The position also includes an unassigned state that allows a following vehicle to be assigned to the position, but movement into the position is prohibited as long as the occupied state remains.Follower position 5, position 474, has a locked state due to the presence of vehicle 490. The described follower positions and the states defined for the various positions are exemplary conditions that may exist, and the disclosure is not intended to be limited to the specific embodiments described. It is noted that the conditions described in . Fig. 19 are considered to be nominal positions that generally describe a formation of the convoy and vehicles arranged in that formation. These nominal positions differ from the actual spaces or distances between vehicle positions, as described herein, for example, with respect to Fig. 17 is described in more detail.

[0036] Positions can be ranked in order of importance, starting with the leader position (position #0, highest importance), then position #1 (highest follower importance), position #2, and so on for all defined positions. Generally, higher-importance positions are located closer to the lead vehicle, although specific formations may employ different procedures. Higher-importance positions are usually assigned to participants ahead of lower-importance positions to keep the formation as compact as possible or to achieve other objectives.

[0037] The lead vehicle's leadership role may be one or a combination of autonomous vehicle systems and a human driver qualified, capable, and willing to guide potentially many follower vehicles along a path. At any given time, a defined navigation objective may exist, or the human driver may manually steer the lead vehicle's path without a specific defined objective. The lead vehicle systems must be able to translate the human driver inputs or the planned navigation route into detailed path and movement commands used to coordinate the overall movement of the follower vehicles. The lead vehicle must be able to send the driving formation definition and position assignments to the follower vehicles and must implement formation management protocols with other vehicles to coordinate changes to formation participation (formation membership).

[0038] Potential Leader vehicles have a defined ambition level that controls how quickly the potential Leader vehicle attempts to claim the lead in situations requiring a new Leader vehicle. If a vehicle is not appropriately equipped for the lead role, the ambition level is set to zero. If the vehicle is used by a less skilled human driver / occupant or by a person who prefers not to serve as a Leader vehicle, the ambition level can be configured low. If two or more potential Leader vehicles have equal ambition levels, the lead is granted on a "first come, first served" basis, although the use of small random additional wait times (similar to the random reset periods in network media access control protocols) can be implemented to further reduce line contention.

[0039] An exemplary method for autonomous or semi-autonomous platoon formation is described in detail. Vehicles begin in a solo mode, although solo mode includes both manual navigation (human-driven) and autonomous navigation (e.g., autonomous "servant" mode). The vehicle may be configured to announce its readiness to create a formation as a lead vehicle and / or to join a formation as a follower vehicle. This readiness may be specified with respect to specific other vehicles; a defined grouping of vehicles, such as a group for a specific human family; or classes of formations. Classes of formations may include virtual school bus formations and general commuter formations. Each vehicle in a solo mode listens for a formation announcement message from other vehicles and responds as appropriate.

[0040] If a potential lead vehicle receives an announcement from a potential follower vehicle and that potential follower vehicle does not indicate a higher level of leadership ambition, and other conditions do not prevent this, the lead vehicle transmits a "Create Formation" message. All potential follower vehicles can then respond with an "Accept Formation" message. If at least one potential follower vehicle responds with an "Accept Formation" message, the potential lead vehicle assumes the lead role and begins serving as the lead vehicle for the new formation. The potential follower vehicles can begin requesting to join the formation, as defined below.

[0041] Convoy control may be a static control scheme, where the formation comprises fixed positions and the convoy responds to the environment around the convoy, acting as a fixed entity. Such a static convoy may be formed at the beginning of a planned route and disbanded as needed, for example, at the end of the planned route. Alternatively, convoy control may comprise dynamic convoy formations, where the convoy responds to changing conditions around the convoy. Likewise, convoy formations, shapes, positions within the formation, and roles within the formation may all be dynamic. Convoy members may, for example, be added to or removed from the convoy midway through a planned route, either as part of a predetermined plan or in response to changing commands from the vehicle occupant.A vehicle may request to change position within the formation, for example, based on a planned maneuver to leave the formation, a desired view from the vehicle, or preferences such as claustrophobia. In another example, a vehicle may be a lead vehicle for an initial portion of a planned route, and at some point, another member may communicate a request to assume the lead role to relieve the current lead vehicle (from a long section of manual driving) or to utilize the vehicle occupant's knowledge of the location being traversed. A number of changes to platoon shape, vehicle positions, and vehicle roles are contemplated, and the disclosure is not intended to be limited to the specific exemplary embodiments described herein.

[0042] Fig.20 illustrates exemplary decisions made when creating a platoon according to the present disclosure. According to the exemplary process, a potential lead vehicle announces to other vehicles a desire to form a platoon. Such an announcement is shown from the potential lead vehicle to another potential lead vehicle or follower vehicle and at least one potential follower vehicle. The announcement is accompanied by a lead ambition value. The other potential lead vehicle and potential follower vehicles can respond, accepting or rejecting the announcement. In addition, the responding vehicles can respond with their own lead ambition value. Based on assumptions and comparisons of the lead ambition, a formation is formed around a lead vehicle, and communication between the lead vehicle and the various follower vehicles is managed.Such a formation is depicted, including the creation of a formation by the lead vehicle, the acceptance of the formation by the follower vehicles, the designation of the lead vehicle, and subsequent exchanges of leader and follower extensions or communications.

[0043] A vehicle that is not currently a member of a formation may send a "Request to Join" message to indicate that it wishes to join. Fig.28 illustrates an exemplary process for a vehicle to join a platoon according to the present disclosure. If at least one available open position exists, the lead vehicle may acknowledge the join request with a "join granted" message and the assigned position of the new vehicle. The lead vehicle generally assigns the new vehicle the highest priority open position whose requirements the new vehicle meets. The lead vehicle may initiate the entry of the requesting vehicle, e.g., commanding the vehicle to a position where the entry can be conducted in an orderly manner. In one exemplary method, a new position may be added to a formation to make room for the following vehicle.In another exemplary method, multiple unused positions may be maintained by the Leader vehicle at any given time, allowing flexibility as vehicles change positions or new members are added. If an unassigned position exists that is claimed or locked, the Leader vehicle may request the new vehicle to "try joining again later." In the meantime, the Leader vehicle may reorganize the formation to improve accessibility for the new vehicle by negotiating with the current formation participants to assume new positions. If the Leader vehicle is able and willing to increase the formation size, a new formation description is sent before the Join Request Accept message is sent to the new vehicle. Note that each position may have minimum commitment requirements (e.g.,Position 1 requires that the occupants be fully admitted, while position 2 does not.

[0044] Fig.Figure 29 illustrates an exemplary process by which positions within a formation may be reassigned, in accordance with the present disclosure. If the lead vehicle detects a situation where a new vehicle cannot join the formation, or other conditions warrant reassigning vehicles to the formation positions, the lead vehicle can simply update the formation position assignment list, and each follower vehicle would be responsible for maneuvering into the newly assigned position. However, the lead vehicle can optionally consult with the follower vehicle by first sending a "position reassignment proposal" message. The follower vehicle can respond with "reassignment of newly assigned position acceptable" or "position reassignment undesirable" (perhaps the follower vehicle intends to leave the convoy in a specific direction, and the new position would be disruptive).If a following vehicle objects to the reassignment of positions, the lead vehicle may attempt another one.

[0045] Fig.30 illustrates an exemplary process by which a follower vehicle may request a position change, in accordance with the present disclosure. If a follower vehicle wishes to exchange places with another follower vehicle, or simply move to another open position in the formation, it issues a "position reassignment request" to the leader vehicle. The leader vehicle may issue a "position reassignment proposal" to any follower vehicle that might be relocated by the proposed reassignment and wait for the response, as described above. If the leader vehicle has any reason to reject the request, it issues a "position reassignment request rejected" message to the requestor. Otherwise, the leader vehicle may simply update the assignments in the position assignments and roles segment of the V2V broadcasts.

[0046] Fig.31 illustrates an exemplary process by which a follower vehicle may request to leave a platoon, in accordance with the present disclosure. When a follower vehicle wishes to leave the formation, it notifies the lead vehicle by sending an "exit notification" message. The lead vehicle sends an acknowledgment message. The position is then considered "released" until the exiting vehicle has physically moved away from the defined position, at which time it may be considered open, locked, or claimed, as appropriate for the existing conditions. The lead vehicle may then reposition other vehicles to fill the released position. The lead vehicle may also reposition the requesting vehicle to facilitate or initiate the vehicle's exit.Later, the former formation participant could be considered an “intruder” if he or she attempts to move back into the formation without asking for and receiving permission to join the formation.

[0047] Fig.Figure 32 illustrates an exemplary process by which a Leader vehicle may relinquish leadership of a platoon and enter a flowing vehicle status, in accordance with the present disclosure. If the Leader vehicle intends to leave the formation or simply wishes another vehicle to assume leadership, the Leader vehicle checks for any specific new Leader vehicle selection from the human driver, and if none is present, the Leader vehicle systems search the current formation participants for another vehicle capable of assuming the lead role, taking into account the significance of the current position, but also characteristics of the human occupant and the configured vehicle settings. Either way, if a new Leader vehicle is identified, the Leader vehicle sends a "New Leader Appointment" message to the formation.The designated Lead vehicle responds with a "Lead Appointment Acceptance" message indicating whether it accepts or declines the appointment. If it is willing to accept, it also defines the provisional formation it will use when it becomes the Lead vehicle (it may be the same or it may define new relative positions, so no physical maneuvering of the current and new Lead vehicles is required, at least initially). When the current Lead vehicle receives the appointment, it sends a "Resignation" message and swaps position assignments with the new Lead vehicle. The new Lead vehicle then begins performing the movement coordination and formation management roles expected of the Lead vehicle.

[0048] Fig. 33 and Fig.34 illustrate an exemplary process by which a follower vehicle may request a change of formation lead and responses that may occur based on the lead vehicle's response, in accordance with the present disclosure. Fig. 33 describes an example reaction if the request is refused. Fig. Figure 34 describes an example response if the request is granted. When steered by the human driver, a follower vehicle in the formation can send a "Request for Leadership" message to the current Lead vehicle and all other formation participants. If the current Lead vehicle receives this, it can send a "Request for Leadership Rejected" message and continue operating as the Lead vehicle. The current Lead vehicle can also respond with the Leader Resignation Protocol, as described above, to implement a smooth transition of leadership.

[0049] Fig.Figure 35 illustrates an exemplary response when communications are lost between a Leader vehicle and Follower vehicles in a formation, according to the present disclosure. In the event of a communications anomaly between the current Leader vehicle and the rest of the formation (as described below), one of the other vehicles may attempt to assume the lead position after a wait period that is a function of that vehicle's current ambition level. To do so, it sends a "Request for Lead" message. If the requesting vehicle does not receive a response from the Leader vehicle within a timeout period (e.g., 100 ms), an exemplary request may require the requester to repeat the request message and wait two more times for a response. If there is still no response at that point, the vehicle requesting the lead must send a "Self-Nomination" message to the formation.If a participating vehicle receives at least two "lead request" messages followed by a "self-appointment" message, it should send an "acceptance" message. If all other vehicles besides the current lead vehicle and the vehicle requesting the lead respond with an acceptance message, the requesting vehicle assumes the lead role and begins serving as the lead vehicle for the remainder of the formation. The new lead vehicle records its new lead start time.

[0050] If any vehicle in the current formation hears a "leadership request" from another participant, it will not attempt to request the lead role itself for a small, fixed period of time plus a wait time that is a function of its ambition level. If the former lead vehicle suddenly regains communication capability and receives a message from the new lead vehicle, it compares the other's lead start time with its own. If the other's start time is more recent, the former lead vehicle immediately transitions to the follower role, assuming the position assigned to it by the new lead vehicle. If the start time is not more recent, a serious time synchronization problem must exist, so fail-safe procedures would be initiated.

[0051] Fig.Figure 36 illustrates an exemplary response when a lead vehicle decides to disband a platoon, according to the present disclosure. The lead vehicle may disband the formation at any time, although it is expected to "warn" the formation participants that the formation is about to end through one of the properties of the transmitted formation definition (one element of the formation data should be a "formation expiration" time). The typical reason a lead vehicle would disband the formation is that the formation has reached a destination and the individual vehicles need to find a suitable parking area. If the formation is disbanded during normal navigation, another vehicle could attempt to create a new formation from the participants of the old formation and guide it to the destination.However, in contrast to this scenario, it would be preferable for the previous lead vehicle to relinquish control as described above to allow for a smooth transition.

[0052] If the lead vehicle detects prolonged situations of impassable and / or encroached positions, or if the lead vehicle driver requests it, the lead vehicle can command a new formation, assign a position within it to each participating vehicle, and broadcast the new position assignments. For example, if the current formation is a "block" pattern, but the drivable road narrows significantly, the lead vehicle can command a "single-file" formation.

[0053] For less dramatic changes in conditions, the lead vehicle adjusts the existing formation pattern rather than switching to a new pattern. For example, the lead vehicle may increase the following spacing within the formation as the platoon speed increases to allow for adequate braking distances. Curves also reduce the formation spacing for the position toward the center of the curve while expanding it on the opposite side. If two vehicles swap positions, additional space could be opened up around them by adjusting the other vehicle positions within the formation. The two vehicles could then be slowly guided through intermediate positions before being assigned the new position assignment IDs.

[0054] A lead vehicle of a formation must establish a speed acceptable to all members of the formation. The lead vehicle checks the speed capabilities of any new vehicle joining the formation and periodically checks the speed capability of each participating vehicle and determines the fastest speed all vehicles are capable of achieving. The lead vehicle may also check the braking capabilities of the following vehicle and reviews a performance-critical vehicle diagnostic before allowing the new member to join the platoon. This determination also includes analyzing motion feedback data, including speed error terms, so that a participant who continues to fall behind, despite their reports of being capable of additional speed, is not left behind by the rest of the formation.This formation speed constraint is used as an upper limit for all navigation planning.

[0055] The example vehicle-to-vehicle communication may be based on periodically sent V2V over-the-air (OTA) transport safety message packets. To this basic information, the formation lead vehicle may append information including the following: path history (in standard V2V OTA format), formation definition (FD), position assignments and additional role assignments (PA), navigation objectives (NG), detailed movement coordination (MC) guidance, an "heard by" list, and any required formation management protocol messages. Formation participants may respond by appending information including the following: movement coordination feedback information, an "heard by" list, and any required formation management protocol messages.

[0056] Fig.Figure 37 illustrates an exemplary connectivity map describing methods for accomplishing extended connectivity between members of a platoon, in accordance with the present disclosure. The formation participants report a list of the other participants they have "heard from" on the wireless communication channel within a recent time window. If the Leader vehicle does not receive reliable communications from one or more of the formation participants, the Leader vehicle scans the "heard from" lists to attempt to identify one or more participants they can hear. The Leader vehicle then assigns "broadcast" roles to as many formation participants as necessary to establish connectivity.

[0057] As described above, methods for managing communication problems between members of a formation can be described. Fig.38 illustrates an exemplary process for managing communication problems within a platoon according to the present disclosure. If the Leader vehicle does not hear from a formation participant for a threshold time and the above "broadcast" method does not work, the participant is considered "lost." While the participant is lost, the Leader vehicle does not reassign the formation position of the lost vehicle to another vehicle. Because the loss of communication may impact Follower-to-Leader transmissions, the Leader vehicle may attempt to change the formation geometry to bring the lost vehicle's formation position closer to the Leader vehicle to clear up communications (assuming the Follower vehicle can still receive at least some of the Leader-to-Follower transmissions).

[0058] If the lead vehicle loses communication with all trailing vehicles for a threshold time, it assumes that the formation has been disbanded or that another vehicle has taken over. Therefore, it switches to a "single-run" mode, but monitors the communication link for messages from its former trailing vehicles. Trailing vehicles must be prepared to switch roles if the lead vehicle becomes unreachable for any reason.

[0059] Even if a follower vehicle does not hear from the lead vehicle (either directly or via a relay vehicle) during a short-term autonomy period (e.g., 0.8 seconds or any defined "look-ahead" period), the follower vehicle will continue to travel along the last received motion coordination guidance path in the short term and attempt to meet the specified position, speed, and heading objectives at the appropriate times.

[0060] In the medium term, each vehicle extrapolates the most recent movement control guidance for an additional medium-term autonomy period, perhaps limited by the defined navigation route (if one exists) and the need to avoid collisions with other formation participants. During this period, a vehicle in the formation qualified to serve in the lead role initiates the "request for leadership" process, as described above. To avoid a power struggle, potential lead vehicles wait a variable amount of time before initiating the request for leadership, depending on their configured "ambition" level. If the self-proclaimed lead vehicle assumes the lead role, the formation can continue as before, although the previous lead vehicle is considered lost.

[0061] In the event of a long-term problem in communication between formation vehicles, or similarly in the event of a disruption in on-board communication systems such as an overloaded controller area network (CAN), a speed profile definition in a control module can be used to apply a desired stopping maneuver profile. If the medium-term autonomy period has elapsed and the follower vehicle has still not heard from the lead vehicle, the follower vehicle will attempt the following fail-safe procedures as an alternative, including, for example, the following: aligning the vehicle's heading with the current direction of travel of the road using a moderate turning rate (if necessary), switching to "single-drive" mode and autonomous navigation if possible, or if autonomous navigation is not possible (e.g.,no route is defined), then start a deceleration with 0.05 g and signal the driver to adopt a manual driving mode.

[0062] With return to Fig.30 illustrates an exemplary process beginning at 800, after which a communication failure is monitored. In step 802, a Leader vehicle communication failure is compared to a short-term autonomy period. Such a short-term autonomy period may be described as a selected period of time during which a vehicle within a platoon formation can operate without transmitted commands from the Leader vehicle. Such a period of time may be calibrated or may be a functional relationship determinable, for example, by the vehicle's speed. If the failure is less than the short-term autonomy period, the process proceeds to step 806. If the failure is not less than the short-term autonomy period, the process proceeds to step 804.In step 806, guidance points used to move the vehicle through a controlled path, previously transmitted to the vehicle by the lead vehicle, are used to calculate motion control commands. In step 808, these commands are issued to control the vehicle. In step 810, feedback data describing the operation and travel of the vehicle is collected, and in step 812, this feedback data is appended to output communications for reception by the rest of the platoon or other nearby vehicles, and the process returns to step 802, where the communication failure continues to be monitored. In step 804, the communication failure is compared to a medium-term autonomy period. Such a medium-term autonomy period may be calibrated or may be a functional relationship.If the outage is greater than the medium-term autonomy period, the process proceeds to step 822. If the outage is not greater than the medium-term autonomy period, the process proceeds to step 814. In step 814, extrapolated lead points are calculated based on available information, including, for example, the lead points that previously existed and any available information regarding the current lane geometry and other vehicles surrounding the vehicle. In step 816, the lead ambition of the present vehicle is calculated. If the lead ambition is high, the vehicle can quickly request the lead for the rest of the platoon that is still in communication with the vehicle.If the lead ambition is low, the vehicle may wait an additional period of time to determine whether the lead vehicle re-establishes communication or any other vehicle in the platoon requests the lead. If, at step 818, the lead ambition is such that it is time for the vehicle to request the lead, then the process proceeds to step 820, in which the vehicle transmits a lead request according to the methods described herein, and the lead request may or may not result in the vehicle being designated as the new lead vehicle. If step 818 determines that it is not time to issue a lead request, or an issued lead request is not accepted by the rest of the platoon, then the process proceeds to step 806, in which short-term action is taken to control the vehicle, as described above.If the process proceeds to step 822, a transition to single-drive outside the platoon is initiated. In step 824, a determination is made as to whether a navigation route has been entered, and the vehicle is instructed as to movement commands to be generated. If such a navigation route exists, the process proceeds to step 826, where the movement commands are generated, and to step 828, where information describing a single-drive state is appended to the output communications. If such a navigation route does not exist, the process proceeds to step 830, where a switch to manual mode is initiated. In step 832, commands, for example, from an HID device or controller, are collected that describe movement commands to be generated. In step 834, information describing a single-drive state is appended to the output communications.In this manner, a vehicle within a platoon as described herein may be controlled via a loss of communication with a lead vehicle.

[0063] An essential role of the lead vehicle is to define a path for the formation to follow and then help guide each participant along the way. Fig.Figure 39 illustrates an exemplary projection of a path for a platoon to follow, according to the present disclosure. The lead vehicle must project a path for each position in the formation and then define short-term targets along the projected paths for each vehicle assigned to those positions. The targets are defined by a set of increasing "look-ahead" periods. For example, each vehicle may be given a position target, a speed target, and a heading target for the following times: 0.1 seconds from now, 0.2 seconds from now, 0.4 seconds from now, and 0.8 seconds from now.

[0064] Each follower vehicle receives the motion guidance information and does its best to achieve the objectives while maintaining a desirable buffer distance between itself and all other vehicles participating in the formation and other objects, while striving to maintain a comfortable ride for occupants and energy efficiency. The motion control processes compare the vehicle's current position with future projected position objectives and determine the basic speed and turn-rate commands for the vehicle's propulsion and steering system to best meet the position objectives and other optimization goals. The follower vehicles report their basic position, heading, and speed information as part of the standard V2V OTA message and add additional feedback, including various error terms for the position, speed, and heading.

[0065] The lead vehicle can adjust the spacing of positions based on the evaluation of the position maintenance performance of each participant vehicle. For example, if a follower vehicle can maintain its assigned relative position very well, i.e., with very small divergences, the lead vehicle can guide it to follow at a smaller spacing. Conversely, the lead vehicle can open additional space in the formation around a participant whose movement includes larger than expected divergences. Position maintenance movement includes evaluation in all of the following performance metrics: position error (RMS) during each of the following: traveling at a constant speed, traveling around a curve, completing an intersection turn, accelerating from a stop, and decelerating to a stop; speed tracking error (RMS); and heading tracking error (RMS).

[0066] Procedure as in Fig.12, improve the driving experience, including methods for automatically controlling the vehicle in the presence of likely collision conditions, and driver comfort. However, as control methods, including methods for determining vehicle position, become more accurate and calculations are capable of real-time operation in tightly formed convoys, additional benefits become possible. For example, slipstreaming is a well-known technique in which close distances are maintained between vehicles to gain aerodynamic advantages, thereby increasing fuel economy or energy efficiency for some or all of the vehicles involved.Furthermore, fuel efficiency can be increased and emissions can be reduced by planning a vehicle journey along a route, for example, by planning the vehicle journey and modulating vehicle operation across an intersection with a traffic light, timing the cycle, and avoiding vehicle stop. The need for a driver in a vehicle is also partially or completely eliminated, reducing or eliminating increased stress and lost productivity associated with the strain of driving, for example on long daily commutes. Furthermore, completely eliminating the need for a driver in a vehicle can relax age restrictions on vehicle operation, for example, allowing a parent to send children to school in an autonomous vehicle without the parent being present in the vehicle.Furthermore, as urban traffic congestion worsens, with traffic jams and associated inhibited movement and delays, methods for automatically controlling vehicle positioning can increase traffic density on roads, enabling automatic, orderly traffic flow with potentially reduced distances between vehicles. The overall carrying capacity of a road can be increased by increasing vehicle density and avoiding traffic slowdowns. Furthermore, the driver experience can be improved, for example, by integrating pedestrian monitoring methods with vehicle control methods, by implementing minimum desired distances, by automating vehicle responses that currently depend on driver detection and response, and by eliminating the driver's tendency to make hasty or impatient traffic decisions.Furthermore, autonomous driving methods can be used to automatically park and retrieve a vehicle, recharge or refuel a vehicle, send the vehicle for maintenance, pick up packages, or perform any other similar tasks while the vehicle's former occupants independently attend to other business, with the vehicle programmed to return at a set time or on command. Furthermore, the methods described herein increase the reliability of methods for automatically controlling vehicles, enabling higher vehicle travel speeds than can currently be used.

[0067] Specific applications of automated control and platoon driving are being considered. For example, urban areas can use vehicles in a platoon to implement mass transit in areas without the tremendous effort and footprint required to install a train or subway system. An automated platoon, or a platoon led by a driven vehicle, with a driver acting like a bus driver, can make circuitous routes in an urban area, making scheduled stops or pass-bys to load and unload individual vehicles from the platoon.Similarly, trucking companies and mining haulage truck operations can also use convoys of automated trucks as a virtual train, reducing the labor required to man the trucks, mitigating the effect of fatigued drivers on the road, and exploiting efficiencies such as slipstreaming to transport goods more efficiently without the investment required for a rail line. Military applications are possible, for example, creating convoys of unmanned or lightly manned vehicles to traverse dangerous areas. Law enforcement applications are possible, for example, placing people in custody in separate and fully locked follow-up vehicles, minimizing contact between potentially dangerous suspects and law enforcement officers.

[0068] This disclosure describes a set of dynamic platoon formation and platoon management protocols that enables efficient autonomous driving of multiple vehicles using low-cost wireless V2V communication, particularly for constrained environments predominantly populated by autonomous vehicles. The programming functionality can enable fail-safe dynamic platoon formation and fail-safe dynamic platoon management.Additionally, the described programming enables formation management and a changing leader-follower platoon formation for various driving scenarios, including example procedures for assigning a new vehicle to the formation, position reassignments within the formation initiated by the lead vehicle, position reassignments within the formation initiated by the follower vehicle, programming to allow vehicles to leave the formation, and reassigning the lead vehicle position to adapt to various driving scenarios. Additional scenarios include a follower vehicle requesting a lead role, programming to disband a formation, managing a loss of communication between vehicles or between a vehicle and an infrastructure system, and scenarios requiring movement coordination guidance.

[0069] Many control methods are considered using information regarding the vehicle's operating environment. Many control methods involve determining a desired distance a vehicle should maintain from surrounding objects or targets. Desired distances can be defined around a vehicle to describe a desired envelope within which other objects are not permitted. Fig.13 illustrates an exemplary vehicle and a desired envelope around the vehicle according to the present disclosure. Example minimum desired distances are defined in four directions around the vehicle and are useful for defining an example desired envelope around the vehicle. Such a desired envelope may be used to control the vehicle by monitoring object trajectories and changing vehicle speed and heading to avoid other objects entering the envelope. Furthermore, communication with other vehicles may be used to coordinate between the vehicles, with both vehicles, for example, changing speed and / or heading to avoid entering the desired envelopes of both vehicles.

[0070] Minimum desired distances for a vehicle are desirable when controlling the vehicle, as described in the methods above. Several methods for defining minimum desired distances are known. Fig. Figure 14 describes an exemplary method for formulating a minimum desired distance ahead of a vehicle according to the present disclosure. A minimum stopping time is described as including a time defined by a minimum braking time, a control reaction time, and additional factors that affect the stopping time. A minimum braking time describes a braking capacity of the vehicle at the current speed. Such braking capacity can be determined for a particular vehicle by many methods, for example, by testing the vehicle at various speeds.

[0071] It can be seen that braking capacity varies for different vehicles, with a large truck, for example, requiring more time to stop than a smaller vehicle. Control response time includes both mechanical responses within the vehicle to a driver or control module commanding a stop, as well as the driver or control module's response time to an impulse indicating a need to stop. Factors affecting stopping time include road conditions; weather conditions; vehicle maintenance conditions, including conditions of the vehicle's braking devices and tire tread; and the operability of vehicle control systems such as ABS brakes and lateral stability control.The factors may include a selectable or automatically calibrated factor for the vehicle's occupants, such as specific driver reaction times and occupant comfort with close distances between vehicles. Stopping time values can easily be translated into minimum desired distances by a person skilled in the art.

[0072] Fig.15 illustrates the operation of an exemplary platoon according to the present disclosure. A lead vehicle 360 and two follower vehicles 370 and 380 are shown traveling within a lane 350 defined by lane markers 355A and 355B. The three vehicles collectively enable a platoon definition that describes the formation and boundaries of the platoon. The lead vehicle may operate under manual control or use control methods to travel within the lane, and the follower vehicles may be controlled by various methods. Fig. For example, FIG. 15 defines a platoon lane keeping boundary defined by lane keeping boundaries 395A and 395B based on control methods used in the lead vehicle, and the following vehicles are controlled to stay within the platoon lane keeping boundaries when the following vehicles follow the lead vehicle.

[0073] The control methods described herein may benefit from operating a group of vehicles as a platoon. Control of other vehicles in a group or platoon may be performed according to the distances between the vehicles, for example, by control methods in each of the vehicles that maintain distances relative to surrounding vehicles and by association from the lead vehicle. In another exemplary control method, the lead vehicle may monitor vehicles in the platoon and issue commands to each of the vehicles to control desired positions of each vehicle within the platoon. In such a system, monitoring the relative positions of vehicles within the platoon while maintaining desired positions of each of the vehicles with respect to one another is desirable.Furthermore, monitoring the positions of vehicles within the convoy relative to the road and objects outside the convoy is desirable when controlling the convoy. Monitoring positions within the convoy can be performed according to the method described above, for example, by using information acquired by radar and vision systems in various vehicles within the convoy and processing the information to describe a complex model of the various positions of the vehicles and the necessary calculations required to navigate the convoy. Although such a method is effective for controlling vehicles within a convoy, radar and vision systems in each vehicle can be prohibitively expensive.Furthermore, the near-constant transmission of complex analyses of distances and relative relationships between vehicles can be prohibitive, requiring high-bandwidth signals and virtually error-free reception of complex signals. In any given communication cycle, the loss of any term required to calculate a vehicle's distance from the host vehicle will block the calculation of the required distance. Furthermore, the computational load within the lead vehicle for controlling numerous vehicles in the convoy using such control methods can be prohibitive.

[0074] An efficient method for controlling vehicles within a platoon by a lead vehicle is disclosed, wherein communication is based on GPS coordinates and uses certain simple values such as distances and relationships between the vehicles, such as vehicle speed. Because the disclosed method enables the determination of vehicle location based on simple GPS coordinates monitored with respect to each of the vehicles within the platoon, the determination of required calculations within a lead vehicle, and the transmission of simple control terms from the lead vehicle to the trailing vehicles, communication between the vehicles requires that less information be exchanged per communication cycle. Furthermore, the method is more robust than communication methods that require the exchange of large amounts of error-free information in each cycle.While previous methods may be blocked for a communication cycle by the loss of individual information values, the disclosed method may incorporate simple redundancy. For example, if a distance from a trailing vehicle to another vehicle in the platoon is corrupted or otherwise not received, a correctly received speed of the trailing vehicle may act as redundant information, allowing a determination of the trailing vehicle's probable distance for that communication cycle. Additionally, a trailing vehicle may report an actual position, actual distance, actual speed, or other terms to allow correction of certain values in the lead vehicle.

[0075] An exemplary method for achieving communication between vehicles is to use radio signals in a dedicated short-range communication (DSRC) format. DSRC signals can be used in a number of ways. In one exemplary format, a two-part signal is transmitted. A first part of the two-part signal is dedicated for communications that describe a minimum desired distance or a desired envelope for vehicles under independent control of the lead vehicle transmitting in DSRC.A second part of the two-part signal may be used for other information, for example, to control vehicles within a platoon. Under one contemplated signaling scheme, the two parts of the signal may be transmitted at different signal strengths, with the first part transmitted at a greater signal strength to most effectively communicate with other vehicles and other platoons not within the control of the lead vehicle's platoon; and with the second part transmitted at a lower signal strength, communicating only with vehicles within the lead vehicle's platoon. Various methods for communicating between the vehicles include, for example, communication over a wireless network.Although known communication over such networks may not be fast enough to enable real-time control of vehicles operating at close ranges in a platoon moving at speed, such communication can be used to convey additional information, such as the presence of an expected stop ahead or incoming information regarding an upcoming traffic light. Furthermore, as wireless networks improve and communication over such networks becomes more timely, the methods used herein may be used over such a network. Additionally, or alternatively, laser scanning signals or other forms of data transmission may be used to communicate between vehicles, for example, as a method of indicating a mandatory stop from the lead vehicle to the platoon.Many forms of communication between vehicles within a platoon are contemplated, and the disclosure is not intended to be limited to the specific methods described herein.

[0076] GPS systems, as described above, enable good accuracy in locating a group of vehicles in close proximity relative to each other. By accurately locating one vehicle in the convoy, GPS information in the remaining vehicles can be used to precisely locate other vehicles in the convoy relative to the location of the precisely located vehicle. Furthermore, GPS information with a coordinate describing a vehicle's location is much easier to transfer between vehicles and requires much less computational effort than relationships determinable by other methods, such as calculations based on radar and visual information in each following vehicle.Furthermore, since GPS data is available in and for each of the follower vehicles, commands to the follower vehicles for maintaining positions within the convoy can be significantly simplified, with the follower vehicles being commanded according to position or distance, rather than detailed vehicle control via the communication signal. By controlling a lead vehicle and using GPS information describing the relative locations of various follower vehicles, control of the follower vehicles can be achieved with minimal communication between the vehicles.

[0077] Operating a platoon of vehicles requires the ability to control each of the vehicles according to a selected platoon formation. Furthermore, operating the platoon requires the ability to navigate the platoon across roads and in relation to other vehicles, traffic signals, and other objects and obstacles necessary to move all vehicles in the platoon. As described above, vehicle-to-vehicle communication, or V2V communication, enables a method for controlling vehicles within the formation and enables the platoon to communicate with other vehicles on the road. Furthermore, vehicle-to-infrastructure (V2I) communication enables the platoon to acquire information from and communicate with systems outside the platoon.As described above, a vehicle's location can be determined using complex and computationally intensive methods using combinations of in-vehicle systems such as GPS, radar, cameras, ultrasonic ranging, and other devices. Known methods for integrating sensor inputs include protocols such as the well-known simultaneous tracking and mapping (SLAM)—an intelligent single-vehicle navigation process. Although such protocols or programming can be effective in controlling a vehicle under certain circumstances, they can be computationally intensive and costly to implement across large numbers of vehicles.An exemplary limitation of such programming includes the presence of significant latency in determining and initiating appropriate autonomous vehicle responses when other vehicles or objects are encountered at intersections or enter the path of the controlled vehicle. Sensor-based control systems must jointly detect and classify objects and their dynamics with a certain degree of certainty before responding to such constantly changing environments, which contributes to the delay. However, by using V2V and V2I communications, methods for locating and controlling the vehicle based on the determined location can be made less complex and less computationally intensive.A communication-based approach shares the information and dynamic state of each vehicle in advance with all connected vehicles, allowing ample time for control modules to plan vehicle movement and adapt to dynamic traffic environments. This characteristic of the V2V and V2I communication-based approach makes vehicle formation and platoon management tasks manageable. Furthermore, reducing the number of components required to operate a vehicle in a platoon can increase system availability, allowing the methods to be shared across all vehicles rather than being a select, expensive feature.

[0078] The methods described above enable the control of a platoon of automated vehicles. However, it should be recognized that manually controlled vehicles may utilize a platoon formation. However, instead of fully automated control, the driver may retain some or all control of the vehicle. For example, a trailing vehicle in a platoon may operate similarly to a vehicle using ACC, a method described above, with automatic vehicle speed control maintaining a distance from the controlled vehicle to a vehicle ahead of the controlled vehicle. In such an application, the driver may retain control of the vehicle's lateral steering.In fully manual operation, an indicator, such as a set of lights, a dashboard display, or a warning indicator, can be used to indicate to the driver a desired distance to maintain the distances required for the convoy. In such an application, the driver can maintain control of the vehicle's speed and lateral steering, but a brake assist module, which overrides manual control when braking is required, can be used to allow closer distances between vehicles than would normally be advisable in manual operation.

[0079] The methods described herein enable the automated control of vehicles in a convoy. However, a certain minimum level of equipment is required to control a vehicle within the convoy. For example, V2V communication is required to enable the definition of desired, but desirable, distances within the convoy. Vehicles without any ability to monitor distance and position within the convoy cannot operate as follower vehicles within the convoy.

[0080] Automated control of a vehicle allows a vehicle to operate as an individually operable vehicle or as a member of a convoy, allowing the driver or occupants of the vehicle to divert their attention from the road and allowing the control system to operate the vehicle. However, it is recognized that automated control of the vehicle can be achieved regardless of the occupant's presence in the vehicle.For example, a vehicle can transport a passenger to work; park automatically and pay any fees through a V2I exchange, for example, using a specified credit account; travel to a maintenance shop, car wash, grocery store, restaurant, or any other facility at a specified time and perform any task authorized by the vehicle's owner or previous occupant; and return to a specified location at a specified time to pick up the passenger at the end of the workday. Alternatively, an unmanned vehicle operating as a taxi service could be operated by a municipality.In another example, parking facilities could be operated at high density, with, for example, vehicles being tightly packed within the facility and navigating a maze within the facility, exiting the facility at a required time input by the driver or occupant. In some parking application, the vehicle could spend some of its parked time in a recharging facility, refilling the vehicle's energy storage device. Automated operation of vehicles could allow several recharging stations within a parking facility to recharge the various vehicles within the facility, with vehicles rotating between the recharging stations. These are example descriptions of how such an automated vehicle might be used.A wide variety of such uses are contemplated, and the disclosure is not intended to be limited to the specific embodiments described herein.

[0081] Automated control of a vehicle allows for easy input of a destination or other commands as a method for operating the vehicle. Designation of destinations, waypoints, or tasks for an automated vehicle may be input through any number of methods. For example, an occupant may possess a human-machine interface (HMI) device to retain control of the vehicle. Such a device could include a convenient form factor with a device similar to and / or consistent with common handheld devices, such as a mobile phone, a navigation device, or a digital assistant / handheld computer.Such a device could utilize key entry of commands; voice commands; touch-screen commands; accelerometer-activated commands; GPS location of the device, for example, to coordinate the occupant's location with the unoccupied vehicle based only on the device's location; periodic synchronization or alternate control through a standard computer interface; control by multiple similar devices, for example, where a child and a parent both have controllers with appropriate authority and monitoring capability in the parent's controller; or some other form of control device.

[0082] The interactivity of an automated vehicle or platoon of vehicles with infrastructure devices enables a number of beneficial advantages for vehicle operation. Intersections that use traffic lights, for example, may include broadcast schedules describing when the light is green or red. Such a broadcast may allow vehicles approaching the intersection to modulate their speed, for example, slowing the vehicle so that the vehicle crosses the intersection when the light turns green, thereby avoiding the need to stop and incurring all the inefficiencies associated with stopping and then accelerating the vehicle. Convoys may also monitor light cycles to allow the entire convoy to navigate to the next green light period without disbanding.Communication with a traffic light can be two-way, allowing, for example, a local traffic authority to extend green light periods to a platoon's reasonable need, thereby enabling greater fuel efficiencies. In another example, traffic lights can be disabled or not used in areas where only automated vehicles are used, with each vehicle monitoring the traffic moving through the intersection and negotiating a path and speed through the intersection with the other vehicles. Such a system could be enabled by giving control of other vehicles to, for example, the vehicle closest to the intersection. An alternative control scheme could be used that models the interplay of people walking across a crowded square or a school of fish.Alternatively, a virtual platoon could be constructed, for example, with minimal management by an infrastructure device, with boundaries at some fixed distance from the intersection in each direction and commands to each vehicle modeling a transforming platoon formation, with position assignments, as in . Fig. 19, which are used entirely here to guide the vehicles across the intersection.

[0083] Vehicles that use V2V and V2I communication methods are necessarily highly connected devices. The use of a wireless connection to enhance navigation and control, for example, is likely to improve the use of the vehicles described. Social networking and other interaction are well known and widespread via the internet and wireless devices. The automated control of a vehicle, combined with time spent in a connecting and mobile device, allows an occupant to participate in social activities within the vehicle. For example, a person could coordinate the formation of a convoy each day with a group of social acquaintances. Connectivity between vehicles could enable reading groups, computer-based games, or some other social activity via monitors in the various vehicles.Alternatively, a driver could search for a group of potentially unknown people traveling along a similar route and suggest forming a convoy. Furthermore, such searches for potential convoy members could be selected based on driving preferences, for example, according to preferred vehicle speed, preferred distances between vehicles, and a preferred convoy formation. In another example, a person could identify friends driving at various locations within an urban area, enabling real-time communication between the person and the friends. Such real-time communication could enable spontaneous social opportunities not considered prior to the conversation.Such opportunities could be enhanced, routes planned, and the plan coordinated within the vehicles using maps and internet content. Routes could involve the vehicles meeting at some point and forming a convoy before reaching an intended destination.

[0084] Commands from the lead vehicle to the following vehicles are required for effective control and management of the platoon. To effectively utilize the various occupants of the vehicles, platoons must share a common schedule. Numerous methods can be considered to establish a common schedule. platoons can be formed at the beginning of a route with a set of known vehicles, and all vehicles can travel according to a single schedule. Alternatively, vehicles can join and leave the platoon along the route, with the shared schedule considering an efficient or selectable joint schedule, with platoon members meeting, traveling together, and members dropping out at points along the shared travel route.Joint schedules can be developed spontaneously during a journey, for example, where three different vehicles traveling on the same road determine a common set of intermediate stops through which a platoon would be advantageous. The formation and management of platoons can be fully automated, with the occupant never selecting a platoon, and a computerized management program either searches for acceptable platoons to join or invites platoon members en route to a joint schedule. Vehicles can communicate directly with other vehicles on a road to search for likely platoon options. Additionally, or alternatively, infrastructure systems can be used, for example, through internet access, to search for vehicles on a given road, or later scheduled to travel on a section of road, to form proposed platoons that share a common schedule.Many uses of shared schedules are contemplated, and the disclosure is not intended to be limited to the specific embodiments described herein.

[0085] The convoy formations are controlled, for example, by commands from the lead vehicle to each of the following vehicles. Fig.16 schematically illustrates an exemplary in-vehicle platoon control system according to the present disclosure. The platoon control system 400 includes an autonomous controller 410, an HMI device 420, an engine controller 430, a GPS device 135, and a DSRC system 440. The autonomous controller 410, including a processor, may be operated in a lead vehicle, which receives data from each of the follower vehicles via the DSRC system 440, GPS data from the GPS device 135, and any other necessary information. The controller 410 performs the necessary calculations to determine appropriate control commands for each of the follower vehicles. These commands may then be sent by the DSRC device 440 to the follower vehicles.Similarly, autonomous controller 410 may be operated in a follower vehicle, which receives commands from a lead vehicle through DSRC system 440 and issues commands to vehicle control systems according to the received commands. HMI device 420 is an interface device that allows a driver to issue commands, enter navigation information, or otherwise provide input to the system. Motor controller 430 receives control messages from autonomous controller 410 and HMI device 420 and issues commands to electric motors that provide motive power and steering control for the vehicle.The motor controller 430 is an exemplary powertrain controller, and it should be appreciated that the motor controller 430 could be replaced with controllers to operate any one or more of the powertrain, steering, and braking systems, including hydraulic or electric steering, internal combustion engines, electric motors, fuel cells, hybrid drive controls, regenerative or friction brakes, or any other similar system. Such controllers may generally be referred to herein as drive controllers. Control module, module, control unit, controller, processor, and similar terms mean any suitable or various combinations of one or more application-specific integrated circuits (ASICs), electronic circuits, central processing units (preferably microprocessors), and associated memory and storage (read-only memory, programmable read-only memory, random access memory, hard disk, etc.).) executing one or more software or firmware programs, combinational logic circuits, input / output circuits and devices, suitable signal conditioning and buffering circuitry, and other suitable components to provide the described functionality. A controller may include a set of control algorithms, including resident software program instructions and calibrations, stored in memory and executed to provide the described functions. The algorithms are preferably executed during predetermined loop cycles. Algorithms are executed, such as by a central processing unit, and are operable to monitor inputs from sensing devices and other networked control modules and to execute control and diagnostic routines to control the operation of actuators.Loop cycles can be executed at regular intervals, for example, every 3.125, 6.25, 12.5, 25, and 100 milliseconds, during continuous vehicle operation. Alternatively, the algorithms can be executed in response to the occurrence of an event.

[0086] A method for monitoring vehicle positions within the platoon includes transmitting a relatively small amount of information from the trailing vehicles to the lead vehicle, determining commands, including desired vehicle positions within the platoon, and using these determined commands to operate the trailing vehicles. Determining commands includes determining distances or separations required to operate the platoon effectively. These separations may include spacing between vehicles within the platoon and may also include determining a range required for the platoon to operate effectively or a desired platoon envelope.

[0087] Close autonomous leader-follower vehicle formations can use in-line and side-by-side positions in a formation. Fig.Figure 17 illustrates an exemplary platoon formation according to the present disclosure. As described above, V2V communication in the disclosed system is advantageous over known systems in that communications between vehicles can be limited to simple terms describing distances and relationships between the vehicles. All vehicles are capable of sharing a set of critical data across the entire platoon, specifically, communicating commands from the lead vehicle to a follower vehicle or reporting actual values from the follower vehicle to the lead vehicle. Critical data may include some or all of the following exemplary list: position, latitude, longitude, elevation, heading, speed, longitudinal and lateral acceleration, braking status, path history, schedule, vehicle size, vehicle type, current operating mode (autonomous or manual), and other platoon control data.Vehicles can also receive traffic light information, map data, and GPS enhancement signals from infrastructure devices, and, if necessary, transmit such information between vehicles. Vehicles can also transmit enhanced information regarding upcoming maneuvers, such as a detected traffic stop a certain distance ahead or a closed lane.

[0088] In Fig. 17 are a lead vehicle L and follower vehicles F1, F2, ... F r , ... F nshown. Between L and F1, a distance or gap is defined between two vehicles of the column D1. Similar distances are defined between different longitudinally spaced vehicles. Each vehicle receives commands from the lead vehicle L and each vehicle is controlled with respect to a lead vehicle or a vehicle directly in front of that vehicle. For example, vehicle F4 receives commands from the lead vehicle L and is commanded to a position based on a distance D4 from its lead vehicle F3. In addition, D LAT1 which describes a lateral distance between different vehicles positioned next to each other. By defining these terms, base locations of positions within the convoy can be defined and controlled.

[0089] When controlling platoon formations, determining desired distances or gaps between vehicles in real time according to increased fuel economy and occupant preferences is a task for autonomous vehicle platoon driving. The system must determine the following distances, positions, and desired driving speeds for all vehicles in the platoon for an improved driving experience and improved fuel efficiency. With automated vehicle control, these values can be communicated directly from the lead vehicle to the controlled follower vehicles. For manually operated follower vehicles, a green zone can be defined to instruct or assist the driver in maintaining the vehicle in the desired positional relationship to a lead vehicle based on criteria such as fuel economy.

[0090] When vehicles in a convoy are controlled automatically by a lead vehicle, it is clear that each follower vehicle must be commanded based on a desired behavior or position of the follower vehicle. The actual distances between the vehicles are a consideration in the operation of the convoy. For example, in Fig.17, a lead vehicle L can command the follower vehicle F1 a position based on the GPS location of the lead vehicle L. As described above, the accuracy of GPS locations is high within a group of vehicles located nearby. Therefore, a commanded position for a follower vehicle F1 based on the distance D1 and the GPS location of the lead vehicle L can be used to control the follower vehicle F1. However, a commanded position for the follower vehicle F2 cannot be based on the commanded position for the follower vehicle F1, but must instead be based on the actual position of its lead vehicle, the follower vehicle F1, directly ahead of the follower vehicle F2, because the actual position is reported by the follower vehicle F1 to the lead vehicle L.Likewise, a commanded position for the follower vehicle Fr must be based on an actual position of its lead vehicle, the follower vehicle F2, since the actual position is reported by the follower vehicle F2 to the lead vehicle L.

[0091] To perform these control functions, the platoon leader vehicle calculates relative real-time platoon position vectors and velocities for each trailing vehicle in the group that ensure the best possible fuel savings and desired operation. Example calculations include selecting the best possible distance between vehicles (D g ) for a known column position, for example based on the vehicle type, calculating a minimum desired distance (D s ) between a following vehicle and a preceding vehicle directly in front of the following vehicle and determining a maximum of D g and D sas the desired column distance (D) between the vehicle in front directly in front of the following vehicle and the following vehicle. D s can be calculated taking into account the following: the current wireless V2V communication quality (e.g., channel congestion, packet error rate); the current vehicle positioning and sensor data accuracy; vehicle size and shape parameters, such as length, cross-sectional area, bumper height; the current and predicted vehicle speeds; the dynamic capability of individual vehicles in the platoon (e.g., braking, acceleration, steering errors, latency); the current road geometry; the road surface; the weather conditions; and the current driving mode (manual or autonomous). The exemplary calculation of D s is described in more detail below.

[0092] Once D is calculated for a particular follower vehicle, the lead vehicle calculates a commanded position for transmission to the follower vehicle, for example, as described above, based on the actual position of the lead vehicle of the particular follower vehicle, D, and other factors such as lane geometry and the platoon formation. The lead vehicle may use wireless communication, such as the DSRC system described above, to periodically transmit this information to the follower vehicles. Each follower vehicle receives the relative position vector and velocity from the platoon leader vehicle and uses this information as targets or setpoints for the steering, position, and velocity control values for use by each of the vehicle's control systems.

[0093] It can be seen that the above system, which describes the lead vehicle performing all calculations for the trailing vehicles, is an exemplary form that the disclosed system may take. Alternatively, the individual trailing vehicles may, for example, calculate individual platoon spacings for themselves based on the schedule, the vehicle, and the control commands received from the platoon lead vehicle, with the trailing vehicle determining deviations from a preferred platoon configuration based on other inputs, such as lane availability or occupant inputs.

[0094] As described above, the trailing vehicles can report their actual position, actual speeds, actual platoon spacing, and other information back to the lead vehicle and other platoon members during each control or communication cycle. In an exemplary system, a control cycle operates at approximately 20 Hz.

[0095] It can be recognized that a system limitation, where follower vehicles calculate their own commands, includes the potential for a follower vehicle in close formation with a lead vehicle to be unable to respond in a timely manner to abrupt changes in the lead vehicle's operation. By determining platoon control commands in the lead vehicle, the lead vehicle's operation can be directly taken into account so that the commands issued to the follower vehicles include an appropriate amount of time for the follower vehicles to respond to the lead vehicle. By determining commands for each of the follower vehicles in the lead vehicle, unpredictability in each of the follower vehicles can also be minimized, reducing the impact on the remaining follower vehicles and allowing for closer spacing between the vehicles than would otherwise be permitted.

[0096] Fuel savings benefits in platoons, also known as slipstreaming, are a well-researched area. All vehicles (not just trailing vehicles) in closely following platoons share this benefit. Research has shown that vehicles within a formation gain the most benefit from platooning, consuming 10% less fuel at the closest gap, and the furthest-back vehicle saves about 7% at the closest gap. For platoon gaps of less than 1.5-2 meters, a lead vehicle also consumes less fuel than its trailing vehicle. This fuel savings results from reduced drag in platoon operation compared to isolated operation.

[0097] Fig.21 graphically illustrates exemplary fuel efficiency savings realized during drafting as a function of separation distance in accordance with the present disclosure. Fig. 22 graphically illustrates exemplary fuel consumption rates as a function of position within a platoon and vehicle separation distances according to the present disclosure. Fig. 23 graphically illustrates exemplary fuel consumption as a function of a fraction of the square root of the frontal area according to the present disclosure. Fig. Figure 24 graphically illustrates fuel consumption as a function of vehicle spacing versus vehicle length according to the present disclosure. Fig.Figures 21-24 clearly demonstrate that fuel savings can be achieved by operating vehicles in close formation and in platoons. Example equations describing projected fuel efficiency for sequential operation can be expressed as the following relationships: % Fuel Savings=ξ*[ΔCDCD] ξ=0.891+[0.031r0+0.000126]CDA / M The expression [ΔCDCD] describes the percentage improvement in the drag coefficient, measured for consecutive operation. The term ξ describes the efficiency factor. The term C D describes a drag coefficient. The term A describes a cross-sectional area. The term M describes the air mass, and 0.031r0 describes the rolling resistance.

[0098] Control commands from the lead vehicle provide instructions to trailing vehicles regarding formation spacing, formation positions, and other commands related to managing the convoy. However, local control of a vehicle can be used to augment commands from the lead vehicle or to assume control of the trailing vehicle in the event of an urgent situation. For example, if the occupant of a particular vehicle feels that the distance to another vehicle is too close, a command from the occupant can be observed to modify distance commands from the lead vehicle. If the occupant of a trailing vehicle observes an urgent situation and issues a steering or braking command, the trailing vehicle can be commanded to break formation in response to the urgent situation.In both circumstances, the DSRC system can be used to simultaneously transmit the change in commands in the following vehicle to the rest of the convoy so that appropriate responses can take place.

[0099] Each follower vehicle receives the relative position vector and velocity from the convoy leader vehicle and uses this information as targets (setpoints) for the steering, position, and velocity control processes. Alternatively, the individual follower vehicles can calculate individual convoy spacings for themselves based on the schedule, the vehicle, and the control commands received from the convoy leader.

[0100] Fig. 25 graphically illustrates a method for selecting a desired distance from a following vehicle to a leading vehicle directly in front of the following vehicle according to the present disclosure. Fig.The data presented in Figure 25 were collected from an exemplary wind tunnel test. A green range of acceptable distance values is defined, which are selected according to the formation preferences described above. Operation within such a green range may be selectable by the vehicle operator, automatically selected by preferences entered into a controller, or by other methods. A green range may be defined in a number of ways depending on the priorities of the platoon or participating vehicle. In one exemplary embodiment, a green range may be defined by a minimum distance at D s and a maximum distance that results in fuel savings of 5%. In another exemplary embodiment, the minimum distance may be defined by D smultiplied by a certain factor based on the driver's comfort level with short following distances or based on weather, visibility, or road conditions. In one embodiment, the green area may be used to indicate a convenient following distance to a driver manually operating the vehicle following the other vehicle. In such an embodiment, an exemplary minimum distance may be defined by D s times a reaction time factor must be defined. Within this green area, a procedure for selecting D g for a known platoon position and a known vehicle. In an exemplary method, calibration curves of both vehicle length versus fuel economy and cross-section versus fuel economy may be referenced, accessed through lookup tables representing information such as in Fig.22-25. The lookup tables and calibration curves for determining D g may be developed experimentally, empirically, predictively, through modeling, or other methods appropriate to accurately determine vehicle operation, and a variety of lookup tables and calibration curves could be used by the same vehicle for different powertrain settings, environmental conditions, or operating ranges. Fig. 25 graphically shows the exemplary selection of D g with respect to a range of potential choices within a defined green area according to the present disclosure.

[0101] D sis the minimum distance between a leading vehicle directly in front of a following vehicle and the following vehicle based on the minimum desired distance calculated by viewing real-time data as follows. A number of factors affecting a following distance can be described, including factors affecting the transmission of commands within the platoon, factors affecting the accurate monitoring of the positions of vehicles within the platoon, speeds of vehicles within the platoon, operating characteristics of vehicles, including acceleration and braking, weather and road conditions. In addition, occupant preference can be considered a factor in determining D s be used, which allows an occupant to have more distance to D s added. D s can be determined from the following example equation: Ds=(N*V) / f+δD+δ1*V+δ2+δ3+β

[0102] The term f describes a frequency of V2V communication. It can be seen that f is used to determine D s is important in that a smaller f describes a larger communication delay, which increases D s required to maintain a preferred distance between vehicles. The term V describes platoon vehicle speed differences or the difference between speeds of different vehicles within the platoon. Small values of V mean that the relative speeds of the different vehicles are small, indicating controlled operation of the platoon and smaller permissible D s -values. Larger values of V indicate that the column formation is not stable and that larger values of D sare advisable based on the instability. The term N can be an integer and describes a probability that a vehicle in the platoon will receive a transmitted packet from the lead vehicle. The term δD describes a difference in minimum stopping distances between trailing vehicles and a corresponding leading vehicle directly in front of the trailing vehicle. The term δ1 describes an estimated computational latency. The term δ2 describes a sum of control and relative position error differences. The term δ3 describes an additional tolerance that can be implemented for bad weather or difficult road conditions. As disclosed herein, the methods described herein can be used to automatically control the vehicles of the platoon. However, it is also described that the disclosed methods can be used with manually operated vehicles. The term β can be used to describe a driver reaction time.β may be a calibrated value, may be selected by a driver, may be a value automatically determined based on measured reaction times of the vehicle driver, or may be determined by any other method that takes driver reaction times into account. According to an exemplary embodiment, for a DSRC packet error rate (PER) of 30% at a distance of 300 m, the number of consecutive packet transmissions (N) required to achieve the packet reception probability P at the vehicles is given by the following relationship. P=1−PERN e.g. N = 4 for 99.2% reception probability, and N = 3 for 97.3% reception probability.

[0103] From D g and D s a selected distance for controlling a vehicle can be determined according to the following equation. D=Maximum(Dg,Ds)

[0104] By selecting a maximum of D g and D s becomes D g selected if it does not violate the minimum desired distance.

[0105] Several methods for controlling a convoy with respect to environmental conditions on a road are considered. Fig. Figure 13 shows a method for controlling a vehicle with respect to environmental conditions on a road using a desired envelope. A similar method can be used with a platoon of vehicles. By evaluating the positions of vehicles within a platoon and applying minimum desired distances from all of the current vehicle positions, a desired envelope can be defined. By controlling the platoon according to a desired envelope, the platoon can be navigated.

[0106] Fig.Figure 27 illustrates the function of an exemplary desired envelope around a platoon of vehicles according to the present disclosure. A lead vehicle 510 and follower vehicles 522, 524, 526, 528, and 530 are shown traveling in a formation on road 500. Minimum desired distances may be determined for each of the vehicles. As described above, minimum desired distances between the vehicles of the platoon are useful for defining the spacing maintained within the formation. However, minimum desired distances for vehicles with one side facing outward from the formation may be used to describe the desired envelope for the platoon. Minimum desired distances for the vehicles with one side facing away from the formation of Fig.27 are shown as distances 540A through 540N. These distances are used to formulate the desired convoy envelope 545. In this way, details regarding the desired operation of the multiple vehicles within a convoy can be used to navigate the entire convoy.

[0107] The minimum desired distances around a column, as defined by the distances 540 in Fig. 27 may be handled according to a number of exemplary methods. According to one exemplary method, a desired platoon envelope (PSE) may be determined, and attention may be drawn to identified or impending violations of the PSE (e.g., non-platoon vehicles within the PSE).

[0108] An exemplary method for determining the dimensions of a PSE is disclosed, Fig.42 illustrates an exemplary method for determining the length of a desired platoon envelope in accordance with the present disclosure. The platoon 1000 includes vehicles 1010, 1020, 1030, 1040, and 1050. Vehicle locations 1012, 1022, 1032, 1042, and 1052 are provided for each of the vehicles 1010, 1020, 1030, 1040, and 1050. The vehicle locations 1012, 1022, 1032, 1042, and 1052 describe a point-defined location of each vehicle, for example, describing the GPS location that each vehicle reports to the lead vehicle. Example distances between vehicles are shown as defined between the vehicle locations. Additionally, a forward tolerance FM and a backward tolerance RM are shown, which describe specific distances required for the column to react to PSE violations. PSE 1005 is shown with a PSE length of 1060.The length of this example platoon can be described as the sum of the distances between the vehicle locations plus the forward and reverse tolerances. However, for different formations, it will be appreciated that a number of other methods can be used to determine the PSE length. For formations occurring over a number of lanes, a PSE length can be determined for each occupied lane, or a PSE length can be applied across lanes based on the overall shape of the formation. Also shown is an SM, or lateral tolerance, which describes a minimum distance that the PSE desirably extends laterally from the sides of the vehicles in the platoon.

[0109] A width of a PSE may be selected according to the methods described herein. Fig.43 illustrates an exemplary method for determining the width of a desirable platoon envelope in accordance with the present disclosure. The platoon 1100 includes vehicles 1110, 1120, 1130, and 1140. The platoon 1100 is illustrated traveling along a roadway having lane marking 1102. It can be appreciated that positional relationships of the various vehicles within a platoon may be managed by the lead vehicle, which, for example, analyzes actual, assigned follower positions and / or commanded positions of the various vehicles and determines a formation width based on the positions. Each vehicle may be described through wireless communication with a Wr, or width, value. These values may be compared, and a widest value may be determined. Fig. 43 shows four vehicles, including a truck, a vehicle 1130, with a certain maximum width of the vehicles in the column, Wmax . A number of exemplary methods can be considered to determine the width of a resulting PSE for the depicted platoon. The platoon width must be at least the width for columns of vehicles in a row, a distance D LAT between the columns of vehicles and two side tolerances 2 * SM for the outer sides of the column. An example equation can be expressed that describes a formation width as follows: Width of the PSE=(n*Wmax+(n−1)*(DLAT)max+2*SM)

[0110] The value n describes the number of columns of vehicles or vehicle lanes within the platoon formation. According to this example equation, all column widths within the platoon are set to W max It can be seen that D LATmay include different values, for example, for different vehicles with different operating characteristics. In one embodiment, SM and D LAT be selected such that the values are equal (SM=D LAT ). In such an embodiment, equation 6 can be expressed as follows: Width of PSE=(n*Wmax+(n+1)*SM)

[0111] Fig. 43 represents a PSE configured according to equation 7. W max , the maximum width of the displayed vehicles, is used to define the width of both columns in which the vehicles can be arranged. For simplicity, vehicles 1130 and 1140 are shown as being at a distance D LAT from each other. However, it can be seen that with regard to the PSE D LAT describes a minimum distance between the columns of vehicles and the vehicles 1120 and 1140 are somewhere in the area defined by W maxdefined area for this column and the PSE is still a valid envelope for the column. Since D LAT in this example is defined as equal to SM, the total width of the PSE 1150 is equal to three times SM plus twice W max In other exemplary embodiments, the PSE may consider lane definitions based on lanes in which vehicles must travel, such as those detected according to the methods described herein. A number of methods for determining the width of a PSE are contemplated, and the disclosure is not intended to be limited to the specific exemplary embodiments described herein.

[0112] It will be appreciated that the shape and size of the PSE may be statically determined. In another embodiment, the shape and size of the PSE may change dynamically based on a number of factors that affect platoon operation. These factors may include a number of vehicles in the platoon; a speed of the platoon; platoon vehicle speed differences; a certain accuracy of vehicle positioning, e.g., quantifying variability in GPS positions; a quality of wireless transmission; dynamic capabilities of the vehicles within the platoon, including, e.g., acceleration, braking, and controllability; a current travel schedule; a geometry of the current road, including a curvature of the road; a condition of the road surface; and weather conditions.Furthermore, the desired envelopes for the convoy can be dynamic, adapting to changes in the formations. The position of a specific vehicle and associated distances can be increased based on a planned maneuver within the formation or changes to the shape of the overall formation.

[0113] Benefits are evident from the use of a navigation method such as a desired platoon envelope. For example, improved platoon-wide driving experiences can be achieved by detecting interactions with vehicles and objects outside the platoon perimeter with a limited number of sensors used around the platoon perimeter, thereby reducing non-communicating sensors in individual vehicles within the formation. The use of a desired platoon envelope in the standard V2V message reduces collision avoidance program complexity and computational load for all V2X (i.e., V2V and V2I)-equipped vehicles. The reduced complexity of the sensors used and the reductions in collision avoidance programs enable the platoon to efficiently utilize communications network resources (i.e., wireless bandwidth).For example, platoon-wide broadcast V2V messages can be transmitted per group of vehicles, thus reducing wireless channel congestion. Furthermore, a dynamic desired bubble size can be used to separately regulate the transmission power for packets to be transmitted within the platoon and outside of it, further reducing wireless channel congestion. Using a single desired platoon envelope in the standard V2V message and including the platoon size parameters in that message instead of including individual vehicle sizes helps reduce computational latency and load on V2X-equipped vehicles and conserves wireless bandwidth. Thus, using a desired platoon envelope in the standard V2V message reduces the collision avoidance process complexity and computational load for all V2X-equipped vehicles.

[0114] The use of a desired platoon envelope can facilitate a number of platoon navigation functions. For example, the desired envelope can be considered within an automatic traffic signal intersection navigator program that modulates platoon operation based on desired minimum headways for platoon vehicles or sets traffic signal requirements. Similarly, a four-way stop sign intersection navigator can use the desired platoon envelope to guide platoon navigation with maximum efficiency. Obstacle detection and avoidance programs can use a desired envelope in a number of ways. For example, if an obstacle is detected in a particular lane that disrupts a certain portion of the platoon, the formation can be adjusted to ensure that the desired envelope is not violated by the obstacle.In the case of a dynamic obstacle, for example, a vehicle ahead of the platoon that slows down and indicates a turn out of the platoon's path, only vehicles that have minimum desired distances expected to be affected by the dynamic obstacle need to be recruited. If a column of five vehicles exists in the particular lane, but a prediction is made that only the first two vehicles in the column will be affected by the dynamically changing obstacle, space can be made in the formation for the two vehicles to change lanes, while the remaining three vehicles in the column can be maintained in their current positions in the formation. During the change, the desired platoon envelope can be reformulated, and reactions can be made if the dynamically changing obstacle does not follow the predicted behavior.

[0115] Likewise, programs for handling urgent situations within the platoon can use desired envelopes to manage reactions within the platoon. For example, if a vehicle in another lane performs a lane change and the desired envelope is violated or incipiently violated, an appropriate evasive response can be initiated, such as a stop command or the immediate return of sensor duties and control of the affected vehicles to the vehicle controllers.

[0116] A lead vehicle may use a number of methods to define the positions that follower vehicles should use. One example method involves transmitting messages using the lead vehicle's path history and defining positions as relative to the path history. By using the path history of the platoon lead as "state commands" for the follower vehicles, the courses defined for the various follower vehicles can be easily defined and maintained within a defined clear path or paths, while avoiding complex calculations required to constantly monitor each vehicle's position in free space and control each path individually.

[0117] A method for managing communications within a vehicle includes managing communications in a CAN operating between various components of a vehicle's control system, in particular, communications of control messages from the autonomous controller to the engine controller. A control message includes a speed profile used to control the vehicle's propulsion. The speed profile includes both a current speed command representing a momentary desired speed of the vehicle, for use in the absence of a communication anomaly (e.g., normal communication), and controlled future speed commands for controllably reducing the speed over a speed profile period, for use in the event of a detected communication anomaly (e.g., full, partial, delayed, erroneous, etc., control message).The controlled future speed commands are generated based on a number of factors in the absence of further communication from the autonomous controller to the motor controller system. Example factors that may be used to generate the controlled future speed commands include a current position of the vehicle, a current speed of the vehicle, a current acceleration of the vehicle, a braking capability of the vehicle, a preferred forward travel distance of the vehicle, and a preferred forward travel speed of the vehicle. A length of the speed profile or a speed profile period over which the speed profile may be effective may be selected in an example embodiment based on the preferred forward travel distance by which the desired movement of the vehicle can be predicted and as determined by the system sensors and V2X communication.For example, the speed profiles are transmitted on the CAN bus, and when received by engine controllers, they have a sufficient number of future speed commands to drive the vehicle even if there is a communication anomaly.

[0118] Such a fail-safe system using speed profiles to represent communication anomalies can increase fuel economy by smoothly controlling vehicle speed and reducing vehicle stops, maintain desired autonomous operation during times when CAN communication is delayed, temporarily lost, or the CAN bus is busy, increase vehicle drivability by reducing speed variation during autonomous operation, and improve travel time by reducing the number of vehicle stops due to data transmission delays. Fig.24 graphically illustrates exemplary speed profiles that may be used in the event of communication anomalies, according to the present disclosure.

[0119] Data exchange between an autonomous controller and a motor controller system involves periodically sending or transmitting a control message, including desired speeds and steering commands, to the latter, and the latter executes these commands in its own control loops. This arrangement assumes a reliable communication medium between the two subsystems (often CAN, Profibus, FlexRay, fieldbus, Ethernet, serial, etc.). Reduced vehicle speeds (e.g., a percentage reduction of the desired vehicle speed) can be used as a mitigation measure by the platform motor controller for situations where this communication is unreliable.Such situations can ultimately lead to a "communication anomaly" condition for the system after a predetermined timeout period, at which point the only option would be to stop the vehicle to mitigate the risk of collisions. This can lead to frequent but temporary system downtimes during autonomous operation, a condition that can be managed by maintaining larger communication timeout threshold periods.

[0120] Fig. 40 schematically illustrates the function of a diagram of an autonomous system architecture, including the operation of a remotely operated portable navigation device that transmits commands to the vehicle control systems, according to the present disclosure. The illustrated autonomous system architecture 600 enhances the operation of the Fig.16, including an autonomous controller 410, a motor controller 430, a GPS device 135, and a DSRC system 440, with additional described components including a manual drive system 610 that allows the driver to control the vehicle; a vehicle interface module 620 including communication devices; and a portable navigation device 630 in communication with the vehicle interface module 620. Additionally, commands between various components of the system are accomplished via a CAN. One of ordinary skill in the art will recognize that signals commonly encountered via the CAN include motion commands: speed profiles, steering / yaw rate; vehicle signals: current speed, longitudinal acceleration, lateral acceleration, yaw rate, braking state, wheel speeds, wheel positions, and battery voltage; and system signals, including communication heartbeats.Also described is an Ethernet connection between the vehicle interface module 620 and the autonomous controller 410. There are two main control commands generated by the autonomous control system: the "Speed Profile" command for the vehicle's longitudinal speed control and the "Steering / Yaw Rate" command for the vehicle's lateral steering control. These two CAN commands are periodically sent as CAN messages from the autonomous controller 410 to the engine controller 430 every 50 milliseconds (or at a higher rate).

[0121] "Speed" and "yaw rate" commands are used for speed and steering control of autonomous vehicles. If CAN bus communication is reliable, the vehicle platform can be reliably controlled using these commands. If, for any reason, CAN communication is delayed (bus shutdown situation) or lost due to packet collisions on the CAN bus, there may be periods of time in the motor controller 430 during which no valid speed commands are to be executed. Some reduced speed (e.g., a percentage reduction in vehicle speed) can be used as a mitigation measure by the platform motor controller in such situations. This may eventually lead to a "CAN bus communication error" after a predetermined timeout period, at which time the vehicle should be stopped to mitigate the risk of collisions.As described above, such a communication anomaly can be controlled using speed commands and speed profiles according to the methods described herein.

[0122] Fig.41 illustrates exemplary speed profile data that may be used to execute a desired deceleration or stopping maneuver, according to the present disclosure. The speed profile data in the CAN control message is intended to provide a set of speeds that the platform engine control system will execute while the "CAN message data delay" (heartbeat delay) is detected. The "speed profile length" field contains a distance value that the autonomous control subsystem has confirmed as clear to travel (according to all of its available information). The speed changes defined in the "Speed Delta_1" through "Speed Delta_4" fields, which are typically defined in a manner that desirably brings the vehicle to a stop at some point in the vehicle's movement, are intended to be executed under the heartbeat delay time.The various speed delta values could be interpreted by the platform motor controllers as follows (not limited to the following numerical values). The CAN speed profile control message can specify any values determined to be appropriate. Exemplary values are described in the following examples: "Command speed" = 10.0 m / s; "Length of the speed profile" = 50 m; "Speed-Delta_1" = -1.5 m / s (the desired Vehicle speed at a distance of 12.5 m is 8.5 m / s); "Speed-Delta_2" = -3.0 m / s (the desired vehicle speed at a distance of 25.0 m is 7.0 m / s); "Speed Delta 3" = -7.0 m / s (the desired vehicle speed at a distance of 37.5 m is 3.0 m / s); and "Speed Delta 4" = -10.0 m / s (the desired vehicle speed at a distance of 50.0 m is 0.0 m / s).

[0123] The methods described herein can work in areas where manually operated vehicles not controlled in platoons and automatically operated vehicles controlled in platoons are driven together on the same roadway in the same lanes. However, it can be recognized that there are several advantages if the traffic on the road can be limited to automated vehicles, since reactions to unpredictable driver responses can disrupt the efficient operation of automatically controlled vehicles. Distances in mixed traffic are desirably extended to maintain improved driving experiences in the face of the unpredictable behavior on the road by manually operated vehicles.

[0124] The formations described above describe a lead vehicle for controlling the creation and operation of a platoon. This vehicle is depicted at a forward location in the formation to fully exploit the advantages of a single vehicle conducting sensing regarding the navigation of the platoon and easily transmitting navigation commands to the other vehicles in the platoon to maintain a desired formation. However, it should be appreciated that the lead vehicle does not need to be located at the forward point in the formation. In such a case, sensor inputs from a vehicle in the forward position in the platoon could be transmitted to the lead vehicle with either no or minimal processing.Alternatively, the lead vehicle could be given some responsibility for determining a desired path by the lead vehicle, thereby reducing the complexity of communication between the lead vehicle and the lead vehicle, while still maintaining control over the formation and distances required to maintain the desired operation of the formation. Such a system could be used by a manually operated lead vehicle with detailed commands from the lead vehicle going to the lead vehicle driver. Alternatively, tasks normally performed by the lead vehicle could be distributed, with, for example, sensor inputs and formation management going to a lead vehicle, while route planning, waypoint management, and similar functions are retained by any other vehicle in the formation.A number of alternative methods for managing roles within the formation are contemplated, and the disclosure is not intended to be limited to the specific exemplary embodiments described herein.

[0125] This disclosure has described new control methods that can be used with known vehicle configurations having standard wheel configurations. However, it can be recognized that, particularly in urban situations, smaller vehicles with non-conventional, shortened wheelbases, especially in dedicated lanes that only allow similar vehicles to travel, may be advantageous for traffic density and the non-conventional energy storage solutions described above. It can be recognized that the methods and systems described herein can be optimized for use with smaller, more maneuverable vehicles with different powertrains, different wheel configurations, and different vehicle control methods.

[0126] The above describes a method for a platoon using a PSE to determine potential PSE violations and maneuver the platoon vehicles to avoid collisions. It will be appreciated that the inter-vehicle communications described herein can be used between a platoon and a vehicle outside the platoon, such as a single vehicle or a vehicle in another platoon. These communications can be used to avoid collisions between the communicating vehicles. For example, considering two lanes traveling in the same direction, a first, faster platoon occupies both lanes and overtakes a second, slower platoon that also occupies both lanes.Based on the foreseeable or actual violation of the PSEs by one or both platoons, the leaders of each platoon may change formation, generating commanded positions for each of the vehicles so that both platoons move into a single column. In this way, the faster platoon may pass the slower platoon, and a collision between the vehicles of the platoons may be avoided. In other examples, the speeds of the platoons or the vehicles within the platoons may be changed to avoid a collision. A number of exemplary responses to particular violations of PSEs between vehicles and platoons are contemplated, and the disclosure is not intended to be limited to the examples described herein.

[0127] The disclosure has described certain preferred embodiments and modifications thereto. Further modifications and changes may occur to others upon reading and understanding the specification. Therefore, it is intended that the disclosure not be limited to the particular embodiment(s) disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims. Legend to Figures 31, 32 and 38

[0128] Legend to Fig. 31 Leader Head Existing Follower(s) Existing Follower(s) Follower(s) Successor Leader Extensions Follower Extensions Leaving Notification Updated Position Assignments Updated Position Assignments V2V Updates V2V Updates Leaving vehicle's position considered "vacating" Position of the leaving vehicle considered "vacating" Leaving Vehicle has cleared, position could be reused for a new vehicle, or filled by current follower Leaving Vehicle has cleared, position could be reused for a new vehicle, or filled by current follower Former Follower Former successor

[0129] Legend to Fig. 32 Current Leader Current Leader Potential New Leader Potential new leader Follower(s) Follower Leader Extensions Follower Extensions New Leader Nomination Appointment of the new leader Leader Nomination Acceptance Provisional Formation Resignation resignation Former Leader, Now Follower Former leader, now successor New Leader New formation and assignments New formation and assignments New leadership takes effect New leadership takes effect

[0130] Legend to Fig. 38 Leader comm. outage < short-term autonomy period? Leader communication outage < short-term autonomy period? 806 Calculate movement control commands for yourself from guide points Issue 808 commands 810 Collect feedback data 812 Add feedback to the output 814 Calculate extrapolated guide points 816 Calculate ambition delay Time to req.? Time to ask? 820 Request guidance Leader comm. outage > medium-term autonom period? Leader communication outage > medium-term autonom period? 822 Transition to single driving 826 Calculate movement commands from route 828 Attach individual information to the outgoing declaration Have navigation route? Navigation route available? 830 Switch to manual mode 832 Collect movement command 834 Attach individual information to the output

Claims

[1] A method for controlling a plurality of vehicles to operate the plurality of vehicles in a convoy, the method comprising: within a lead vehicle selected from among several vehicles: monitoring a respective actual position of each of the plurality of vehicles other than the lead vehicle through vehicle-to-vehicle short-range communication based on data from a respective global positioning device in each of the plurality of vehicles other than the lead vehicle; Monitoring the operation of the column at a column speed; Determining a forward tolerance of a desired column shell based on the monitored operation of the column; Defining the desired platoon envelope based on the respective actual position of each of the plurality of vehicles other than the lead vehicle and the forward tolerance; Monitoring an operating environment around the column; Determining a violation of the desired column shell based on the operating environment; and selecting a respective commanded vehicle position for each of the plurality of vehicles based on the violation of the desired platoon envelope; Transmitting each corresponding commanded vehicle position to the respective one of the plurality of vehicles that is not the lead vehicle; and Operating each respective one of the plurality of vehicles other than the lead vehicle based on the respective commanded vehicle position. [2] The method of claim 1, wherein operating each respective one of the plurality of vehicles other than the lead vehicle based on the respective commanded vehicle position comprises changing a formation of the platoon based on the violation of the desired platoon envelope. [3] The method of claim 1, further comprising monitoring vehicle-to-infrastructure communication; and wherein defining the desired platoon envelope is further based on the vehicle-to-infrastructure communication.

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