Braking method for autonomous vehicle system, vehicle, storage medium and program product

Abstract

A method of decelerating a plurality of vehicles along a roadway can include, at a first vehicle, receiving a first brake initiation signal and a first deceleration value from an adjacent downstream vehicle, the first deceleration value indicative of a deceleration rate of the adjacent downstream vehicle, determining a first distance relative to the adjacent downstream vehicle, and determining a second deceleration value based at least in part on the first distance, the second deceleration value configured to prevent a collision of the first vehicle with the adjacent downstream vehicle. The method can also include decelerating at an upper deceleration value according to a determination that the second deceleration value is greater than or equal to the upper deceleration value, and decelerating at the second deceleration value according to a determination that the second deceleration value is less than the upper deceleration value and greater than a lower deceleration target.

Description

[0001] Cross-references to related applications

[0002] This Patent Cooperation Treaty patent application claims priority to U.S. Provisional Patent Application No. 63 / 041,513, filed June 19, 2020, entitled “Braking and Signaling Scheme for Autonomous Vehicle Systems,” the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The described embodiments generally relate to vehicles, and more specifically to braking and signaling schemes for autonomous vehicles within an autonomous vehicle system. Background Technology

[0004] Vehicles such as cars, trucks, vans, buses, trams, and the like are ubiquitous in modern society. Cars, trucks, and vans are often used for personal transport of relatively few passengers, while buses, trams, and other large vehicles are frequently used for public transport. Vehicles can also be used for parcel delivery or other purposes. Such vehicles can travel on roads, including surface roads, bridges, highways, overpasses, or other types of right-of-way. Driverless or autonomous vehicles can alleviate the need for individuals to manually operate vehicles to meet their transportation needs. Summary of the Invention

[0005] A method for decelerating multiple vehicles along a road may include: at a first vehicle, receiving a first braking initiation signal and a first deceleration value from a nearby downstream vehicle, the first deceleration value indicating a deceleration rate of the nearby downstream vehicle; determining a first distance relative to the nearby downstream vehicle; and determining a second deceleration value based at least in part on the first distance, the second deceleration value being configured to prevent the first vehicle from colliding with the nearby downstream vehicle. The method may further include decelerating with the upper deceleration value based on a determination that the second deceleration value is greater than or equal to the upper deceleration value; and decelerating with the second deceleration value based on a determination that the second deceleration value is less than the upper deceleration value and greater than a lower deceleration target. The second deceleration value may also be based at least in part on a speed of the first vehicle, a speed of the nearby downstream vehicle, and the first deceleration value. The upper deceleration value may correspond to a maximum deceleration value that the first vehicle can withstand without skidding.

[0006] The method may further include: sending a second braking initiation signal and the upper deceleration value to a neighboring upstream vehicle based on the determination that the second deceleration value is greater than or equal to the upper deceleration value. The method may further include: sending the second braking initiation signal and the second deceleration value to the neighboring upstream vehicle based on the determination that the second deceleration value is less than the upper deceleration value and greater than a lower deceleration target.

[0007] The method can further include, in accordance with a determination that the first deceleration value is less than or equal to the lower deceleration target, maintaining a speed of the vehicle; and after the speed of the vehicle is maintained for a period of time: detecting a deceleration of the proximate downstream vehicle; and in response to detecting the deceleration of the proximate downstream vehicle, decelerating at the lower deceleration target.

[0008] The proximate downstream vehicle can include an optical output system configured to send information and the first vehicle can include an optical sensing system configured to receive information sent by the optical output system. The first brake initiation signal can be sent via the optical output system of the proximate downstream vehicle and received by the optical sensing system of the first vehicle. The first deceleration value can be sent as an encoded signal via the optical output system of the proximate downstream vehicle.

[0009] A vehicle can include a drive system configured to propel the vehicle, a brake system configured to decelerate the vehicle, a steering system configured to steer the vehicle, and a vehicle controller configured to: receive a first brake initiation signal and a first deceleration value from a proximate downstream vehicle, the first deceleration value indicative of a deceleration rate of the proximate downstream vehicle; determine a first distance relative to the proximate downstream vehicle; and determine a second deceleration value based at least in part on the first distance, the second deceleration value configured to prevent a collision of the vehicle with the proximate downstream vehicle. In accordance with a determination that the second deceleration value is greater than or equal to an upper deceleration value, the vehicle controller can cause the brake system to decelerate the vehicle at the upper deceleration value; and in accordance with a determination that the second deceleration value is less than the upper deceleration value and greater than a lower deceleration target, the vehicle controller can cause the brake system to decelerate the vehicle at the second deceleration value. The vehicle can further include an optical output system configured to send the deceleration information to the proximate upstream vehicle and an optical sensing system configured to receive the first brake initiation signal and the first deceleration value.

[0010] The vehicle controller can also be configured to determine the second deceleration value based at least in part on a speed of the vehicle and a speed of the proximate downstream vehicle. The vehicle controller can also be configured to send deceleration information to a proximate upstream vehicle including a second brake initiation signal and the upper deceleration value in accordance with a determination that the second deceleration value is greater than or equal to the upper deceleration value. The vehicle controller can also be configured to send deceleration information to the proximate upstream vehicle including the second brake initiation signal and the second deceleration value in accordance with a determination that the second deceleration value is less than the upper deceleration value.

[0011] A method of decelerating a plurality of vehicles along a roadway can include receiving, at a first vehicle, a first brake initiation signal and a first deceleration value from a proximate downstream vehicle, the first deceleration value indicating a deceleration rate of the proximate downstream vehicle, and determining a second deceleration value configured to prevent a collision of the first vehicle with the proximate downstream vehicle. The method can include sending a second brake initiation signal and an upper deceleration value to a second vehicle in accordance with a determination that the second deceleration value is greater than or equal to the upper deceleration value, and decelerating at the upper deceleration value. The method can also include receiving, at the second vehicle, the second brake initiation signal and the upper deceleration value from the first vehicle, and determining a third deceleration value configured to prevent a collision of the second vehicle with the first vehicle. The method can also include sending a third brake initiation signal and the third deceleration value to a proximate upstream vehicle in accordance with a determination that the third deceleration value is less than the upper deceleration value and greater than a lower deceleration target, and decelerating at the third deceleration value.

[0012] The method can also include sending, at the second vehicle, the third brake initiation signal and the upper deceleration value to the proximate upstream vehicle in accordance with a determination that the third deceleration value is greater than or equal to the upper deceleration value, and decelerating at the upper deceleration value.

[0013] A method of determining a deceleration rate for a plurality of vehicles in a platoon of vehicles can include, at each respective vehicle in the platoon, determining a respective distance relative to a respective proximate upstream vehicle and determining a respective deceleration value based at least in part on the respective distance, and at a vehicle in the platoon associated with a first deceleration value and traveling at a speed, receiving a braking indication from a proximate upstream vehicle and a second deceleration value for an upcoming braking event of the proximate upstream vehicle. The method can further include decelerating at an upper deceleration value in accordance with a determination that the first deceleration value is greater than or equal to the upper deceleration value, decelerating at the first deceleration value in accordance with a determination that the first deceleration value is less than the upper deceleration value and greater than a lower deceleration target, and maintaining the vehicle at the speed in accordance with a determination that the first deceleration value is less than or equal to the lower deceleration target.

[0014] The method can further include, at each respective vehicle in the platoon, determining a speed of the respective proximate upstream vehicle and the respective deceleration value can be determined based at least in part on the speed of the respective proximate upstream vehicle.

[0015] The method can further include, at the vehicle, detecting deceleration of the proximate upstream vehicle and decelerating at the lower deceleration target after maintaining the vehicle at the speed. The upper deceleration value can correspond to a maximum deceleration value that the vehicle can sustain without skidding, and the lower deceleration target can be 2.0 meters per second squared or less. BRIEF DESCRIPTION OF DRAWINGS

[0016] The present disclosure will be readily understood by those skilled in the art from the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:

[0017] Figure 1 A portion of an example roadway is depicted.

[0018] Figures 2A-2B An example vehicle is depicted.

[0019] Figures 3A-3C A top view of a roadway with vehicles decelerating according to a braking control scheme is depicted.

[0020] Figure 4 Two example vehicles are depicted.

[0021] Figure 5 A plot of deceleration rates for some vehicles traveling in a group is depicted.

[0022] Figure 6 Multiple vehicles decelerating according to a braking control scheme are depicted.

[0023] Figures 7A-7B An example vehicle is depicted.

[0024] Figures 8A-8B depictions Figures 7A-7B a vehicle door opens.

[0025] Figure 9 depictions DETAILED DESCRIPTION

[0026] Reference will now be made in detail to the representative embodiments illustrated in the drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. On the contrary, it is intended to cover alternatives, modifications, and equivalents, which are included in the spirit and scope of the described embodiments as defined by the appended claims.

[0027] Embodiments herein generally relate to a transportation system in which a number of vehicles can operate autonomously to transport passengers and / or cargo along a roadway. For example, a transportation system or service can provide a fleet of vehicles operating along a roadway to pick up passengers at predetermined locations or stops or dynamically selected locations, such as selected by a person through a smartphone. As used herein, the term "roadway" can mean a structure that supports a number of moving vehicles.

[0028] Autonomous operation of a vehicle is a complex task, however, the particular technology or approach that the vehicle takes on the roadway can have a significant impact on the operation of the overall system as well as the comfort and safety of passengers and / or cargo in the vehicles. One important aspect of safe operation of the transportation system is braking. For example, to maximize the efficiency and throughput of the transportation system, it is advantageous to minimize the distance between the vehicles. However, the closer the vehicles are to each other, the more critical it is for following vehicles to be able to stop safely in the event that a leading vehicle needs to unexpectedly slow down, such as to avoid an obstacle on the roadway. Accordingly, the safety and efficiency of a transportation system can be improved by providing a robust braking system in which leading vehicles can quickly disseminate information about their upcoming braking events and following vehicles can quickly react to information received from the leading vehicles while also disseminating information about upcoming braking events to more following vehicles.

[0029] Various techniques and systems are described herein for providing robust and safe braking operations for autonomous vehicles in a transportation system. One aspect of such techniques and systems involves an optical communication system that allows vehicles to communicate with each other in a fast, reliable manner. For example, as described herein with respect to Figures 2A-2BAs described, the vehicles can each include optical output systems and optical input systems that facilitate sending and receiving braking information, such as a brake indication (e.g., an alert indicating an impending or active braking event) and information about the braking event (e.g., a deceleration rate of the vehicle during an impending or active braking event). Such systems can allow braking event information to quickly pass through a platoon of vehicles so that each vehicle can even begin decelerating at an appropriate rate before detecting deceleration of downstream vehicles. As used herein, deceleration means a decrease in speed. It should be understood that a deceleration rate or value can also be characterized as a negative acceleration rate or value. For purposes of calculations or evaluations described herein, either sign convention can be used.

[0030] The vehicles can also operate according to a braking control scheme that defines how vehicles in a platoon react to braking events and also attempts to minimize the number of vehicles that must implement high deceleration values that can be uncomfortable for passengers. For example, as described herein with respect to Figures 4-5 As described, the vehicles can each be configured to monitor a speed and distance of an adjacent upstream vehicle (e.g., the immediately preceding vehicle) and continuously determine a deceleration rate that is needed to prevent a collision with the adjacent upstream vehicle. In the event that the adjacent upstream vehicle must decelerate, such as in an emergency situation to avoid a collision with an object or other obstacle in the roadway, the adjacent upstream vehicle can send information about the impending braking event, such as a planned deceleration rate, to the following vehicle. The following vehicle can then determine how it should react according to the planned deceleration rate of the upstream vehicle and its own safe deceleration rate. The following vehicle can also provide information to more upstream (e.g., following) vehicles so that they can each determine how to react according to the planned deceleration rate of the downstream vehicle and their own safe deceleration rates. As described herein, if vehicles simply react to detected deceleration of downstream vehicles, this system allows vehicles to begin decelerating earlier and also reduces the number of vehicles in a platoon (or otherwise close to each other) that must decelerate above a comfortable level.

[0031] As used herein, "downstream" refers to objects (e.g., vehicles) ahead of a particular vehicle or location in a direction of travel, and "upstream" refers to objects (e.g., vehicles) behind a particular vehicle or location in the direction of travel. Thus, for example, in a line of vehicles traveling west to east, the vehicle at the east end of the line is considered to be downstream of all the other vehicles in the line. Likewise, the vehicle at the west end of the line is considered to be upstream of all the other vehicles in the line. Furthermore, unless otherwise noted, the terms "leading" and "trailing" are used to indicate relative position, not absolute position. Thus, a leading vehicle can be any vehicle ahead of another vehicle or downstream of another vehicle, and a trailing vehicle can be any vehicle behind another vehicle or upstream of another vehicle.

[0032] The vehicles in the system can share braking and / or deceleration information using optical communication techniques and / or systems. For example, each vehicle can include an optical sensing system and an optical output system. The optical output system can be configured to send or output information such as brake initiation signals (e.g., an indication that a braking event is imminent or occurring), planned deceleration values, etc. The optical output system can include lights that are selectively illuminated to convey information. Optical output from one vehicle can be detected by the optical sensing system(s) of other vehicles.

[0033] Figure 1 A portion of a roadway 100 for autonomous vehicles 108 according to embodiments described herein is illustrated. Figure 1 The illustrated portion of roadway is shown on a ground surface in a typical urban or suburban environment, but this is not meant to be limiting. In fact, the roadway can be deployed in any environment or location, including rural locations, entirely or partially within a building, off-road, on an elevated structure, underground, etc. The roadway 100 is shown with four-wheeled vehicles 108 navigating along the roadway 100. The vehicles 108 can be autonomous or semi-autonomous vehicles specifically designed for the roadway 100. One example type of vehicle for the roadway 100 is described with reference to Figures 7A-9 Other types of vehicles can travel along the roadway 100 instead of or in addition to those described herein. In the roadway 100 as described herein, the vehicles 108 are autonomous or semi-autonomous vehicles that are specifically designed for the roadway 100. In other embodiments, the vehicles 108 can be vehicles that are not specifically designed for the roadway 100, but are capable of operating on the roadway 100. For example, the vehicles 108 can be vehicles that are capable of operating in a manual mode, an autonomous mode, or a semi-autonomous mode. Figure 1The illustrated road segment can be only a small portion, can include multiple road segments, including straightaways, curves, intersections, bridges, tunnels, boarding areas, parking facilities, etc. To facilitate safe and efficient vehicle operation, the vehicles 108 on the road 100 can employ a braking control scheme whereby information about braking events is rapidly disseminated among the vehicles, and the vehicles intelligently determine rates at which they can and should slow to maintain safety and comfort.

[0034] Figure 2A and Figure 2B An example vehicle 108 is illustrated. As described herein, the vehicle 108 can be configured for bidirectional operation. Thus, the vehicle 108 can include an optical communication system 200 (e.g., optical communication system 200-1, 200-2) at each end of the vehicle. Each optical communication system can include an optical output system 201 (e.g., optical output system 201-1, 201-2) configured to transmit information to other vehicles and an optical sensing system 204 (e.g., optical sensing system 204-1, 204-1) configured to detect and / or receive information from other vehicles (e.g., from the optical output system of another vehicle). This configuration provides several advantages. For example, regardless of which end of a vehicle is acting as the "front" of the vehicle, the vehicle can receive information from a leading vehicle and transmit information to a trailing vehicle. Moreover, by having both an optical output system and an optical sensing system at both ends of the vehicle, bidirectional communication is possible (e.g., the vehicle can communicate with both upstream and downstream vehicles).

[0035] The optical output system 201 can include a plurality of light sources 202. By selectively illuminating the plurality of light sources according to an encoding scheme, the optical output system 201 can transmit information via the plurality of light sources 202. The optical output system 201 can be configured to transmit various types of information to other vehicles (and respective optical sensing systems can be configured to receive), including, for example, deceleration information. Deceleration information can include deceleration initiation signals and / or deceleration values. As used herein, a deceleration value can mean a deceleration rate, and these terms can be used interchangeably unless otherwise specified. Other types of information that can be transmitted and received by the optical communication system 200 can include, but are not limited to, the number of vehicles ahead in a platoon, planned or upcoming acceleration and / or deceleration events, information about upcoming maneuvering (e.g., right turn, left turn, planned stop), the number or type of payload in the vehicle (e.g., people or cargo), etc.

[0036] Many of the brake initiation signals can indicate that the signaling vehicle is experiencing a deceleration or braking event, and the deceleration values can indicate the rate at which the vehicle is decelerating or will decelerate. Other information can also be sent, such as a time of an upcoming deceleration event that is expected or predicted, times of upcoming turning events (e.g., a lead vehicle will turn at a time and degree), upcoming accelerations, etc.

[0037] A following vehicle can receive the information from a lead vehicle's optical output system 201 (e.g., via the following vehicle's optical sensing system 204, as described herein) and react according to a braking control scheme. For example, upon receiving deceleration information from a lead vehicle, the following vehicle can determine whether it should begin to decelerate, what deceleration rate it should use, and what information to send to other following vehicles.

[0038] Optical output from a vehicle can be detected and / or received by another vehicle's optical sensing system 204. The optical sensing system 204 can include components such as lenses, image sensors, processors, memory, imaging software and / or firmware, and / or other suitable components that facilitate the capture and / or analysis of images and, optionally, the decoding of captured information. The optical sensing system 204 can have optical characteristics (e.g., focal length, field of view, resolution) and be oriented such that an adjacent vehicle's optical output system 201 can be optically detected by the optical sensing system 204.

[0039] As described above, the information sent by the optical communication system 200 can be in an encoded format. For example, where the optical output system 201 includes multiple light sources, such as Figures 2A-2B As shown, each light source can convey a bit of information (e.g., an off light source conveys a value of 0, an on light source conveys a value of 1). Thus, for example, an optical output system 201 including eight light sources 202 can facilitate an eight-bit information channel. More or fewer light sources can be used to transfer an appropriate amount of information between vehicles.

[0040] In some cases, some light sources are used for binary or other encoded communication, while other light sources are used to convey dedicated single-bit information channels. For example, in Figures 2A-2BIn the illustrated optical output system 201, one light source can be reserved as a brake indicator conveying a brake initiation signal (e.g., if the light source is on, braking and thus deceleration is currently active; if the light source is off, braking is not active), while the remaining seven light sources are used as a seven-bit channel to convey information, such as a deceleration value associated with the braking event (or an upcoming braking event). The seven-bit channel can also be used to convey other information, such as vehicle speed, upcoming maneuver (e.g., turn, acceleration, deceleration), type of cargo in the vehicle (e.g., packages, passengers), or the like.

[0041] The optical communication system 200 can be used to rapidly propagate deceleration information between vehicles, more specifically to upstream vehicles. As described above, the information can include not only the fact that a leading vehicle is actively braking, but also the actual deceleration value at which a leading vehicle is or will be braking. Furthermore, the use of optical communication can allow more upstream vehicles to begin preparing (or initiating) a braking maneuver even before these vehicles are able to detect the actual deceleration of an immediately downstream vehicle.

[0042] Figures 3A-3C A top view of a road 302 is depicted, with a plurality of vehicles 300 (300-1 through 300-7) traveling along the road 302 in a direction of travel 301. Figures 3A-3C To illustrate how deceleration information, such as deceleration values, can be propagated upstream through a platoon or other group of vehicles. More specifically, Figures 3A-3C To illustrate how deceleration information can travel through the vehicle group 300 even faster than a physical braking event.

[0043] Figure 3A To illustrate the road at a time tO. At this time, the vehicle 300-1 can detect an obstacle in the road or otherwise need to begin a braking event. After (or optionally before) the vehicle 300-1 initiates a braking event, the vehicle 300-1 can begin braking (as indicated by the circled x symbol) and can send to an adjacent upstream vehicle 300-2 a deceleration value 305 indicating the rate of deceleration of the vehicle 300-1. The vehicle 300-1 can also send a brake initiation signal (e.g., indicating that braking is occurring). In Figure 3A At the illustrated time tO, the wavefront of the deceleration value 305 and the wavefront of the actual braking maneuver are both at location 304.

[0044] Due to the speed of optical communication, the wavefront of the deceleration value information can rapidly propagate through the vehicle group 300. For example,Figure 3B The road 302 is illustrated at time t2. At this time, the vehicles 300-2, 300-3, and 300-4, 300-5, 300-6, and 300-7 have received deceleration values from the upstream vehicles, even though in fact only the vehicles 300-1, 300-2, 300-3, 300-4 have initiated deceleration. Thus, the wave front of deceleration values travels further upstream (e.g., to location 314) than the wave front of the physical braking maneuvers (e.g., to location 312).

[0045] Figure 3C The road 302 is illustrated at time t2. At this time, the vehicles 300-2, 300-3, and 300-4, 300-5, 300-6, and 300-7 have received deceleration values from the upstream vehicles, even though in fact only the vehicles 300-1, 300-2, 300-3, 300-4 have initiated deceleration. Thus, the wave front of deceleration values travels further upstream (e.g., to location 314) than the wave front of the physical braking maneuvers (e.g., to location 312).

[0046] Figures 3A-3C The road 302 is illustrated at time t2. At this time, the vehicles 300-2, 300-3, and 300-4, 300-5, 300-6, and 300-7 have received deceleration values from the upstream vehicles, even though in fact only the vehicles 300-1, 300-2, 300-3, 300-4 have initiated deceleration. Thus, the wave front of deceleration values travels further upstream (e.g., to location 314) than the wave front of the physical braking maneuvers (e.g., to location 312).

[0047] When multiple vehicles are travelling in a line or group, a leading vehicle must perform a deceleration maneuver (e.g., due to an unexpected obstacle or hazard on the road), the leading vehicle can have to decelerate very quickly to avoid a collision with the obstacle or hazard. In some cases, the leading vehicle can need to decelerate at an upper deceleration value, which can correspond to a maximum deceleration value that the vehicle can sustain without slipping (e.g., without the wheels locking up and causing continuous slipping or skidding between the vehicle’s tires and the road). However, such a rapid deceleration can be uncomfortable for passengers and can increase mechanical wear and stress on the vehicle. Thus, it would be advantageous to reduce the number of vehicles in the group that need to decelerate at the rate. For example, instead of each vehicle decelerating at the same maximum rate, each vehicle can independently determine its own deceleration rate according to a scheme that causes upstream vehicles to decelerate slower (e.g., a lower deceleration value) than downstream vehicles, if it is safe to do so. The optical communication system of the vehicles facilitates such a scheme, as each vehicle can assess its deceleration requirements according to the actual deceleration rate of the vehicle in front of it.

[0048] In one example braking control scheme, each vehicle continuously (e.g., periodically) determines a minimum deceleration rate that is needed to prevent a collision with an immediately upstream vehicle (which can be referred to herein as the vehicle’s base deceleration rate). Then, when a vehicle receives information that the immediately upstream vehicle is going to start braking, it can assess its base deceleration rate with the deceleration rate advertised by the immediately upstream vehicle, and determine what deceleration rate it should use for its own braking event, and what deceleration rate it should advertise or send to a following vehicle. This braking control scheme can be configured so that upstream vehicles decelerate slower than downstream vehicles, if it is safe to do so. Figures 4-6 An example braking control scheme is illustrated to cause more upstream vehicles to decelerate at a lower deceleration value than downstream vehicles, thereby reducing the overall impact of a braking event (especially an emergency braking event) on other vehicles on the road.

[0049] As described above, each vehicle in the transportation system can be configured to continuously or cyclically determine a minimum deceleration rate that is needed to prevent a collision with an immediately upstream vehicle. Figure 4 Two example vehicles, vehicle A 400 and vehicle B 402, are illustrated travelling in the same direction (e.g., to the right). Vehicle A 400 can be travelling at a speed V A and vehicle B 402 can be travelling at a speed V Btravel, and vehicle B can be a distance d behind vehicle A. Each vehicle can include a number of sensors that allow it to determine these values. For example, each vehicle can have a speedometer so that it can determine its own speed, and additional sensor system(s) that allow it to determine the distance d and the speed of an immediately downstream vehicle. Such sensor systems can include short-range sensors (e.g., optical, ultrasonic, etc.), radar (radio detection and ranging), lidar (light detection and ranging), imaging systems, or any other suitable type of sensing system, as well as any associated circuitry, processors, memory, hardware, software, firmware, or the like that facilitate the sensing function. In some cases, a following vehicle (e.g., vehicle B 402) can base its own speed (e.g., as measured by a speedometer, GPS, or other system) and changes in distance d (if any).

[0050] Given these values, a base deceleration rate for vehicle B 402 may be defined by equation 1:

[0051]

[0052] where, is the reaction time of vehicle B 402 (e.g., the time between when a decision is made to decelerate and when the vehicle actually begins its deceleration maneuver), and is the deceleration value received from vehicle A 400 via the optical communication system of the vehicle (e.g., the optical communication system 200, Figures 2A-2B ). As described above, each vehicle can continuously or periodically calculate its base deceleration rate so that it maintains an accurate base deceleration value in the event of an unexpected braking event.

[0053] When vehicle B 402 receives a braking indication signal from the optical communication system of an immediately upstream vehicle (e.g., vehicle A 400) and the deceleration value to be used by the immediately upstream vehicle (e.g., vehicle A 400) during the upcoming braking event, vehicle B 402 can evaluate its base deceleration rate relative to the received deceleration value of vehicle A 400 and take one or more actions based on the evaluation. For example, vehicle B 402 can determine whether its base deceleration rate is greater than or equal to an upper deceleration value (e.g., the maximum deceleration value that vehicle B 402 can sustain without skidding). In accordance with a determination that the base deceleration rate is greater than or equal to the upper deceleration value, vehicle B 402 can decelerate with the upper deceleration value (e.g., by causing a braking system of the vehicle to decelerate the vehicle). This determination and corresponding action reflect the fact that, if vehicle B 402 is to avoid a collision with vehicle A 400, it must decelerate at the maximum safe rate.

[0054] On the other hand, if vehicle B 402 determines that its base deceleration rate is less than the upper deceleration value and greater than a lower deceleration target, vehicle B can decelerate with its base deceleration rate (e.g., by causing a braking system of the vehicle to decelerate the vehicle). The lower deceleration target can correspond to a deceleration rate that is comfortable for passengers of the vehicle, or otherwise selected based on safety, comfort, passenger preferences, or any other suitable factor. For example, the lower deceleration target can be approximately 1.5 meters per second squared (m / s2), 2.0 m / s2, 2.5 m / s2, 3.0 m / s2, or any other suitable value.

[0055] If vehicle B 402 determines that its base deceleration rate is less than or equal to the lower deceleration target, vehicle B 402 can maintain its speed for at least a period of time before beginning to decelerate. This can be due to the fact that an emergency level of braking (e.g., above the lower deceleration target) and an immediate braking response (e.g., before detecting an actual deceleration of a proximate downstream vehicle) can not be necessary to avoid a collision. Instead, vehicle B 402 can drive according to a normal operating mode in which it is at the lower deceleration target when it detects an actual deceleration of a proximate downstream vehicle. Thus, for example, after maintaining its speed for a period of time, vehicle B 402 can detect an actual deceleration of the proximate downstream vehicle (vehicle A 400), such as by determining a decrease in distance between the vehicles, and, in response to detecting the deceleration of the proximate downstream vehicle, begin to decelerate at the lower deceleration target (e.g., by causing a braking system of the vehicle to decelerate the vehicle).

[0056] To continue to propagate information through a group of vehicles, vehicle B 402 can also send information to proximate upstream vehicles, and the particular information sent can be based at least in part on the deceleration value that it has selected based on information from a downstream vehicle. For example, in accordance with a determination that the base deceleration rate is greater than or equal to the upper deceleration value, vehicle B can send a brake initiation signal and the upper deceleration value to a proximate upstream vehicle. On the other hand, in accordance with a determination that the base deceleration rate is less than the upper deceleration value and greater than the lower deceleration target, vehicle B 402 can send a second brake initiation signal and the base deceleration rate to the proximate upstream vehicle.

[0057] The information sent from the upstream vehicle to vehicle B 402 informs the upstream vehicle that vehicle B 402 is starting its braking event and also indicates the deceleration value that vehicle B 402 will use. Thus, the immediately upstream vehicle can determine for itself how much deceleration it should use by applying the same or similar operations described with respect to vehicle B 402. This scheme facilitates the rapid propagation of braking information and also results in a natural attenuation of braking aggressiveness by a group of vehicles, such that any given vehicle does not have to use a greater deceleration than is necessary for comfort and / or safety. In other words, each vehicle determines whether it is possible to decelerate at a more moderate rate than a downstream vehicle given factors such as its speed, distance to the downstream vehicle, the impending deceleration rate of the downstream vehicle, etc. If it is possible and safe to decelerate at a lower rate, it will decelerate at that rate, with the result that more upstream vehicles are allowed to decelerate at even lower rates.

[0058] Figures 5-6 To illustrate how the foregoing braking and communication scheme results in an attenuation or reduction of deceleration rates toward the upstream vehicles in a group of vehicles. For example, Figure 5 A plot 500 illustrating six example vehicles (x-axis) with deceleration rates (y-axis). Vehicle 1 can be the first vehicle in a group to encounter an obstacle or need to perform an emergency braking operation. In this example, vehicle 1 determines that in order to avoid (or increase the chances of avoiding) a collision or other problem, it must decelerate at an upper deceleration rate 502 (e.g., a maximum deceleration value that vehicle 1 can sustain without skidding). As described above, vehicle 1 will send a braking initiation signal and its deceleration rate (e.g., maximum value) to an immediately upstream vehicle (vehicle 2).

[0059] In the plot 500, vehicle 2 can evaluate its own deceleration rate (e.g., as calculated by equation 1) against the deceleration rate received from vehicle 1 to determine how to decelerate (and what information to provide to vehicle 3). In this example, vehicle 2's own calculated deceleration rate (from equation 1) is lower than the upper deceleration rate but higher than a lower deceleration target 504. As described above, in this case vehicle 2 will decelerate at its own calculated deceleration rate. Figure 5

[0060] ​Vehicle 3 also determines its own deceleration rate (e.g., calculated by Equation 1), receives a brake initiation signal and the deceleration rate of vehicle 2 from vehicle 2, and evaluates its own deceleration rate against the deceleration rate received from vehicle 2 to determine how to decelerate (and what information to provide to vehicle 4). In the example shown, the calculated deceleration rate of vehicle 3 (from Equation 1) is also below the upper deceleration rate 502 but above the lower deceleration target 504. As described above, in this case, vehicle 3 will decelerate at its own calculated deceleration rate rather than the upper deceleration rate 502 or the lower deceleration target 504.

[0061] In Figure 5 the example, vehicle 4 is the first vehicle that can safely decelerate at the lower deceleration target 504. Specifically, vehicle 4 determines its own deceleration rate (e.g., as calculated by Equation 1), receives a brake initiation signal and the deceleration rate of vehicle 3 from vehicle 3, and evaluates its own deceleration rate against the deceleration rate received from vehicle 3 to determine how to decelerate (and what information to provide to vehicle 5). Because the calculated deceleration rate of vehicle 4 (from Equation 1) is at or below the lower deceleration target 504, vehicle 4 can wait to decelerate until it detects that vehicle 3 is decelerating, and can start decelerating at the lower deceleration target 504 at that point.

[0062] Vehicle 4 also sends to vehicle 5 the actual deceleration of vehicle 4 (here, the lower deceleration target 504) and a brake initiation signal. Vehicle 5 can therefore determine that its own deceleration rate is also at or below the lower deceleration target 504. As such, once vehicle 5 detects that vehicle 4 is actually decelerating, vehicle 5 can also decelerate at the lower deceleration target 504. Vehicle 6 can operate in the same manner as vehicle 5.

[0063] In Figure 5 the plot 500 in FIG. 5 demonstrates how the brake control scheme described herein results in a decay of the deceleration rates through a group of vehicles. More specifically, because each vehicle determines its own safe deceleration rate and because each vehicle has the right to choose its own deceleration rate if doing so is safe, the system can prioritize safety and comfort while also minimizing or reducing traffic flow disruption.

[0064] One reason for allowing upstream vehicles to decelerate at a lower deceleration rate than downstream vehicles is that the vehicles can be configured to maintain a fixed (or at least predetermined) time interval between the vehicles. In other words, the vehicles can maintain, for example, a two-second interval from each other, regardless of their speed. Under these conditions, the distance between the vehicles will increase as the speed increases, and decrease as the speed decreases. The ability of the vehicles to reduce the physical distance between the vehicles allows the upstream vehicles in a group of vehicles to use progressively lower deceleration values, as described with respect to Figure 5

[0065] Figure 6 Further to illustrate how to maintain a time interval (rather than a fixed or predetermined distance interval) between the vehicles to facilitate progressively lower deceleration values in a group of vehicles. In particular, Figure 6 A first vehicle 602, a second vehicle 604, and a third vehicle 606 are illustrated traveling to the right of the page. At time to, the gap 608 between the adjacent vehicles can represent equal time intervals (e.g., two seconds, three seconds, four seconds, or any other suitable time), and each vehicle can be traveling at the same speed or near the same speed.

[0066] At time to, the first vehicle 602 can determine that it must perform a braking maneuver. For example, the first vehicle 602 can detect an object 600 (e.g., an obstacle) in the roadway or in the path of the first vehicle 602, and thus determine that it needs to decelerate. While the object 600 is shown as a simple square, this represents any obstacle, location, object, or indeed anything that a vehicle can encounter and should avoid, including but not limited to a hole, a pothole, a curb, an animal, another vehicle, a chemical or other spill on the road, a light pole, an intersection, a stop sign, a red light, a rock, a puddle, an unidentifiable object, road debris, a construction sign, a guardrail, a building, etc.

[0067] The first vehicle 602 can determine a deceleration value necessary to avoid colliding with or otherwise interacting with the object 600. The deceleration value can be based at least in part on the speed of the first vehicle 602, the distance to the object 600, the motion characteristics of the object 600 (e.g., speed, direction of motion, acceleration, etc.), an upper deceleration value (e.g., a maximum deceleration value that the first vehicle 602 can sustain without skidding), existing road conditions, current tire conditions. Other factors can also be used to determine the deceleration value for the first vehicle 602.

[0068] ​Time tl illustrates an example of the relative positions of vehicles 602, 604, 606 during a braking event initiated when the first vehicle 602 begins braking. As shown at tl, the first vehicle 602 is decelerating at a relatively high rate, as illustrated by a deceleration magnitude indicator (e.g., deceleration magnitude indicator 618). The boldness of a deceleration magnitude indicator can represent and / or indicate the relative magnitude of the deceleration value being employed by the vehicle. As shown, from to to tl, the first vehicle 602 has decelerated a distance 612. On the other hand, the second vehicle 604 is able to decelerate a distance 614 that is greater than the distance 612. The greater distance 614 available to the second vehicle 604 can be due, at least in part, to the fact that at slower speeds, the physical distance between vehicles can decrease while still maintaining a target time interval. For example, although the physical distances of the gaps 608, 610 differ (e.g., gap 610 is less than gap 608), the time interval between the vehicles at times to and tl can be the same. Returning to the second vehicle 604, because it is able to decelerate a distance 614 that is greater than the distance 612, it is able to employ a lower deceleration value, as indicated by the less bold deceleration magnitude indicator 620. Similarly, because the third vehicle 606 can shorten its distance from the second vehicle 604 during braking (while still maintaining the same safety time interval represented by the gaps 608 and 610), the third vehicle 606 is able to decelerate a distance 616 that is greater than the distance 614. Thus, the third vehicle 606 can apply an even lower deceleration value, as indicated by the least bold deceleration magnitude indicator 622.

[0069] As described above, Figure 6 The vehicles in the chain can communicate with each other to provide deceleration values and braking indication signals. For example, each of the trailing vehicles receives the deceleration values of the immediately downstream vehicle, allowing the trailing vehicles to calculate their own deceleration values (e.g., using Equation 1 above), compare their calculated deceleration values to the upper and lower deceleration targets, and determine how to decelerate based on the comparison.

[0070] In this application, the term braking can mean any operation that causes a vehicle to decelerate, and is not limited to any particular scheme or technique for causing the vehicle to decelerate. For example, braking can be accomplished using a number of braking systems, such as mechanical friction that resists wheel motion (e.g., disc brakes, drum brakes, etc.), motors that apply a torque to the wheels to resist wheel motion (e.g., electric, internal combustion, etc.), pneumatic braking systems (e.g., parachutes, movable fins, wings, or other objects), external friction-based systems (e.g., poles, plates, or other objects forced into contact with the ground, a track, or another object), forced ventilation systems (e.g., rockets, turbines, fans, etc.), or any other suitable system (or a combination of the foregoing or other systems).

[0071] The braking control schemes described herein can be used with or by a transportation system in which a number of vehicles are autonomously operated to transport passengers and / or cargo along a roadway. For example, a transportation system or service can provide a fleet of vehicles that operate along the roadway. The vehicles in such a transportation system can be configured to operate autonomously, such as according to one or more vehicle control schemes. As used herein, the term autonomous can mean a mode or scheme in which vehicles can operate without continuous, manual control by a human operator. For example, a driverless vehicle can navigate along a roadway using automated drive systems and steering systems that control the speed and direction of the vehicle. In some cases, the vehicle can not require passenger control of steering, speed, or direction, and can not include passenger-accessible accelerator and brake pedals, steering wheels, and other manual controls. In some cases, the vehicle can include manual drive controls that can be used for maintenance, emergency overrides, etc. Such controls can be hidden, stowed, or otherwise inaccessible directly by a user during normal vehicle operation. For example, they can be designed to be accessed only by trained operators, maintenance personnel, or similar personnel.

[0072] Autonomous operation need not exclude all human or manual operation of the vehicle or the entire transportation system. For example, a human operator can intervene in the operation of a vehicle for safety, convenience, testing, or other purposes. Such intervention can be local to the vehicle, such as when a human driver controls the vehicle, or remote, such as when an operator sends commands to the vehicle through a remote control system. Similarly, certain aspects of the vehicle can be controlled by a passenger of the vehicle. For example, a passenger in a vehicle can select a target destination, select a route, select a speed, control the operation of doors and / or windows, etc. Thus, it should be understood that the terms "autonomous" and "autonomous operation" do not necessarily exclude all human intervention or operation of an individual vehicle or the entire transportation system.

[0073] The vehicles in the transportation system can include various sensors, cameras, communication systems, processors, and / or other components or systems that help facilitate autonomous operation. For example, the vehicles can include a sensor array that detects magnets or other markers embedded in the roadway and helps the vehicle determine its location, position, and / or orientation on the roadway. The vehicles can also include wireless vehicle-to-vehicle communication systems, such as optical communication systems (e.g., optical communication system 200, Figures 2A-2B ), that allow vehicles to inform each other of operational parameters, such as deceleration information (e.g., brake initiation signals, deceleration values, etc.), the number of vehicles ahead in a platoon, acceleration status, their next maneuver (e.g., right turn, left turn, planned stop), their number or type of payload (e.g., people or cargo). The vehicles can also include wireless communication systems to facilitate communication with a transportation system controller that has supervisory command and control over the transportation system (e.g., using cellular, WiFi, or other suitable wireless communication technology).

[0074] The vehicles in the transportation system can be designed to enhance the operation and convenience of the transportation system. For example, a primary goal of the transportation system can be to provide comfortable, convenient, fast, and efficient personal transportation. To provide personal comfort, the vehicles can be designed to facilitate ingress and egress by passengers and can be equipped with comfortable seating arrangements with ample legroom and headroom. The vehicles can also have a sophisticated suspension system that can provide a comfortable ride experience and dynamically adjustable parameters to help maintain vehicle level, position at a convenient height, and ensure a comfortable ride over a range of variable load weights.

[0075] Conventional personal automobiles are primarily designed to travel in only one direction. This is partly due to the fact that the driver is facing forward, and long distance reverse operation is often unsafe or unnecessary. However, in an unmanned vehicle, where a human is not directly controlling the operation of the vehicle in real time, it can be advantageous for a vehicle to be capable of bi-directional operation. For example, a vehicle in a transportation system as described herein can be substantially symmetrical, such that the vehicle lacks a visually or mechanically distinct front or back. Furthermore, the wheels can be controlled sufficiently independently that the vehicle can operate substantially identically regardless of which end of the vehicle is facing the direction of travel. Such a symmetrical design provides several advantages. For example, by potentially eliminating the need for a U-turn or other maneuvering to re-orient the vehicle, the vehicles can maneuver in smaller spaces in order that they face "forward" before embarking on a journey.

[0076] Figure 7A and Figure 7B is a perspective view of an exemplary four-wheel road vehicle 700 (herein simply a "vehicle") that can be used in a transportation system as described herein. The vehicle 700 can be an embodiment of the vehicle 108 Figures 1-2B ) or any other vehicle described herein. Figures 7A-7B To illustrate the symmetry and bi-directionality of the vehicle 700. In particular, the vehicle 700 defines a first end 702 as shown by the foremost edge in Figure 7A and a second end 704 as shown by the foremost edge in Figure 7B In some examples and as shown, the first end 702 and the second end 704 are substantially identical. Furthermore, the vehicle 700 can be configured such that it can be driven with either end facing the direction of travel. For example, when the vehicle 700 is travelling in the direction indicated by arrow 714, the first end 702 is the front end of the vehicle 700, while when the vehicle 700 is travelling in the direction indicated by arrow 712, the second end 704 is the front end of the vehicle 700.

[0077] The vehicle 700 can also include wheels 706 (e.g., wheels 706-1 through 706-4). The wheels 706 can be paired according to their proximity to the ends of the vehicle. Thus, the wheels 706-1, 706-3 can be positioned near the first end 702 of the vehicle and can be referred to as a first pair of wheels 706, and the wheels 706-2, 706-4 can be positioned near the second end 704 of the vehicle and can be referred to as a second pair of wheels 706. The wheels can be driven by a drive system, which can include motors, engines, motor controllers, speed controllers, computers, processors, and any other suitable components, systems, subsystems, or the like that facilitate propelling (and optionally braking) or decelerating the vehicle. Each pair of wheels can be driven by at least one motor (e.g., an electric motor), and each pair of wheels can be capable of causing the vehicle to turn. Because each pair of wheels is capable of turning to cause the vehicle to turn, the vehicle can have similar driving and handling characteristics regardless of the direction of travel. In some cases, the vehicle can operate in a two-wheel steering mode, in which only one pair of wheels causes the vehicle 700 to turn at a given time. In such cases, the particular pair of wheels that causes the vehicle 700 to turn can change when the direction of travel changes. In other cases, the vehicle can operate in a four-wheel steering mode, in which the wheels operate in concert to cause the vehicle to turn. In a four-wheel steering mode, the pairs of wheels can turn in the same direction or in opposite directions, depending on the steering maneuver being performed and / or the speed of the vehicle.

[0078] The vehicle 700 can also include a plurality of doors 708, 710 that open to allow passengers and other payloads (e.g., packages, luggage, cargo) to be placed within the vehicle 700. The plurality of doors 708, 710, described in greater detail herein, can extend over the top of the vehicle such that they each define two opposing side sections. For example, each door defines one side section on a first side of the vehicle and another side section on an opposite second side of the vehicle. Each door also defines a top section that extends between the plurality of side sections and defines a portion of the roof (or top side) of the vehicle. In some cases, the plurality of doors 708, 710 have a cross-section that resembles an inverted “U” and can be referred to as canopy doors. The plurality of side sections and the top section of the plurality of doors can be formed as a rigid structural unit such that all components of the door (e.g., the plurality of side sections and the top section) move in unison with one another. In some cases, the plurality of doors 708, 710 include a monocoque or door chassis that is formed from a unitary structure. The monocoque or door chassis can be formed from a composite sheet or structure including, for example, fiberglass, carbon composite, and / or other lightweight composite materials.

[0079] The vehicle 700 can also include a vehicle controller that controls operation of the vehicle 700 and systems and / or subsystems of the vehicle. For example, the vehicle controller can control the drive system, braking system, steering system, suspension system, doors, etc. of the vehicle to facilitate vehicle operation, including navigating the vehicle along a roadway in accordance with one or more vehicle control schemes and controlling operation of the braking system in accordance with one or more braking control schemes described herein. The vehicle controller can also be configured to communicate with other vehicles (e.g., via the optical communication system 200), the transportation system controller, and / or other components of the transportation system. For example, the vehicle controller can be configured to receive information from other vehicles regarding the positions of those vehicles in a platoon, speeds, upcoming speed or direction changes, upcoming braking events, etc. The vehicle controller can include a computer, processor, memory, circuitry, or any other suitable hardware components and can be interconnected with other systems of the vehicle to facilitate the operations described herein and other vehicle operations.

[0080] Figure 8A and Figure 8B are side and perspective views of the vehicle 700 with the plurality of doors 708, 710 in an open state. Because the plurality of doors 708, 710 each define two opposing side sections and a roof section, an unbroken interior space 802 can be revealed when the plurality of doors 708, 710 are open.Figure 8A and Figure 8B In the depicted example, when the plurality of doors 708, 710 are opened, an open section can be defined between the plurality of doors 708, 710 that extends from one side of the vehicle 700 to the other. This can allow passengers on either side of the vehicle 700 to access the vehicle 700 without obstruction. There is no overhang when the plurality of doors 708, 710 are open, which can allow passengers to walk through the vehicle 700 without the constraint of an overhanging gap.

[0081] The vehicle 700 can also include a plurality of seats 804 that can be positioned at opposite ends of the vehicle 700 and can face each other. As shown, the vehicle includes two seats 804, but other numbers of seats and other seat arrangements are possible (e.g., zero seats, one seat, three seats, etc.). In some cases, the plurality of seats 804 can be removed, folded, or stowed so that a wheelchair, stroller, bicycle, or luggage can be more easily placed in the vehicle 700.

[0082] A vehicle for use in a transportation system as described herein, such as the vehicle 700, can be designed for safe and comfortable operation, as well as ease of manufacture and maintenance. To achieve these advantages, the vehicle can be designed to have a frame structure that includes many of the structural and operational components of the vehicle (e.g., motors, suspension, batteries, etc.) and is positioned low to the ground. A body structure can be attached or secured to the frame structure. Figure 9 To illustrate a partial view of a vehicle, which can be an embodiment of the plurality of vehicles 108, 700 (or any other vehicle described herein), an example configuration of a frame structure and body structure is shown. As described below, the low position of the frame structure, in combination with a relatively light body structure, results in a very low center of gravity for a vehicle, which improves the safety and maneuverability of the vehicle. For example, when the vehicle encounters a sloped road surface, wind loads, a sharp turn, or the like, the low center of gravity reduces the risk of the vehicle tipping over, and also reduces the tendency of the body of the vehicle to roll to the side during a turn or other maneuvering Figure 9 maneuvers. Furthermore, by positioning many of the operational components of the vehicle, such as motors, batteries, vehicle controllers, sensors (e.g., sensors that detect road-mounted magnets or other markers), and the like, on the frame structure (e.g., the frame structure 904,

[0083] Figure 9FIG. 9 is a partial exploded view of a vehicle 900, which can be an embodiment of the vehicle 700. Details of the vehicle 700 can be equally applicable to the vehicle 900, and are not repeated here. The vehicle 900 can include a body structure 902, which can include doors (e.g., the doors 708, 710, as described above) and other body members, attached to a frame structure 904.

[0084] The frame structure 904 can include drive, suspension, and steering members of the vehicle. For example, the frame structure 904 can include a wheel suspension system (which can define or include wheel mounts, axles, or hubs, represented as points 912 in FIG. 9), a steering system, a drive system (e.g., electric motors, engines, etc.), a braking system (e.g., disc brakes, drum brakes, etc.), and optionally a motor controller. Wheels can be mounted to the wheel suspension system via wheel mounts, axles, hubs, or the like. The drive motors can include one or more drive motors that drive the wheels, independently or in cooperation with one another. The drive motors can receive power from a power source (e.g., a battery) mounted on the frame structure 904. The motor controller for the drive motors can also be mounted on the frame structure 904. Figure 9

[0085] The suspension system can be any suitable type of suspension system. In some cases, the suspension system includes an independent suspension system for each wheel. For example, the suspension system can be a double wishbone torsion beam suspension system. The suspension system can also be dynamically adjustable, such as to control ride height, suspension pre-load, damping, or other suspension parameters while the vehicle is stationary or moving. Other suspension systems can also be considered, such as swing axle suspension, sliding pillar suspension, MacPherson strut suspension, or the like. Furthermore, spring and damping functions can be provided by any suitable components or systems, such as coil springs, leaf springs, pneumatic springs, hydro-pneumatic springs, magneto-rheological dampers, or the like. The suspension system can be configured to operate in conjunction with a profile of a road surface (e.g., a profile of a road as described above) to maintain a passenger-desired experience.

[0086] The frame structure 904 can also include a steering system that allows the wheels to be turned to steer the vehicle. In some cases, the wheels can be independently steerable, or they can be connected (e.g., by a rack) so that they always point in substantially the same direction during normal operation of the vehicle. Furthermore, this allows the vehicle to use a four-wheel steering scheme, as well as to alternate between two-wheel steering and four-wheel steering schemes.

[0087] ​The frame structure 904 may include a number of components, such as a battery, a motor and a mechanism for opening and closing the doors, a control system (including a computer or other processing unit) and the like.

[0088] Figure 9 An example configuration of the vehicle and frame structure is illustrated. However, other configurations are also possible. Furthermore, Figure 9 The frame and body structures shown are intended more as illustrative representations of these components, and these components may include elements omitted for clarity. Figure 9 Other structures that are omitted. Besides Figure 9 In addition to those explicitly indicated, further structural connections and integrations can be made between the vehicle body structure and the frame structure. For example, components of a door mechanism for opening and closing the various doors of the vehicle body structure can be connected to the various doors and the frame structure.

[0089] For purposes of explanation, the foregoing description uses specific terminology to provide a thorough understanding of the described embodiments. However, it will be apparent to those skilled in the art that the specific details are not required to practice the described embodiments. Therefore, for purposes of illustration and description, the foregoing description of specific embodiments described herein is presented. Their purpose is not to be exhaustive or to limit the embodiments to the precise forms disclosed. In view of the foregoing teachings, many modifications and variations will be apparent to those skilled in the art. For example, while the methods or processes disclosed herein are described and shown with reference to specific operations performed in a particular order, these operations may be combined, subdivided, or reordered to form equivalent methods or processes without departing from the teachings of this disclosure. Furthermore, structures, features, components, materials, steps, processes, etc., described herein with respect to one embodiment may be omitted from or incorporated into other embodiments. Additionally, while the term "roadway" is used herein to refer to a structure supporting numerous moving vehicles, the road described herein may not necessarily conform to any definition, standard, or requirement that may be associated with the term "road," such as those used in laws, regulations, traffic regulations, etc. Therefore, the road described herein may not necessarily (and in fact may not) provide the same features and / or structure as a conventional "road." Of course, the roads described herein may comply with any and all applicable laws, safety regulations, or other rules concerning the safety of passengers, bystanders, operators, construction workers, maintenance personnel, etc.

Claims

1. A method for decelerating multiple vehicles along a road, characterized in that: include: At the location of the target vehicle: Received from a nearby leading vehicle: A brake indication signal instructing the adjacent leading vehicle to initiate braking operation; and A first deceleration value, the first deceleration value indicating a deceleration rate of the adjacent leading vehicle; and In response to receiving the braking indication signal: Determine a first distance relative to the nearest leading vehicle; A second deceleration value is determined at least in part based on the first distance, the second deceleration value being configured to prevent the target vehicle from colliding with the adjacent leading vehicle; Based on the determination that the second deceleration value is greater than or equal to an upper deceleration value, deceleration is carried out at the upper deceleration value; Based on the determination that the second deceleration value is less than the upper deceleration value and greater than the lower deceleration target, Decelerate at the second deceleration value; and Based on the determination that the second deceleration value is less than or equal to the lower deceleration target: After receiving the braking instruction signal, maintain the speed of the target vehicle for a period of time; and After maintaining the target vehicle's speed for a period of time, the target vehicle decelerates.

2. The method as described in claim 1, characterized in that: It also includes sending a message to a nearby following vehicle based on the determination that the second deceleration value is greater than or equal to the upper deceleration value: A second braking initiation signal; and The aforementioned deceleration value.

3. The method as described in claim 2, characterized in that: Also includes: Based on the determination that the second deceleration value is less than the upper deceleration value and greater than the lower deceleration target, the following information is sent to the adjacent following vehicle: The second braking initiation signal; and The second deceleration value.

4. The method as described in claim 1, characterized in that: Also includes: Based on the determination that the first deceleration value is less than or equal to the lower deceleration target, maintain a speed of the target vehicle; and After the target vehicle maintains its speed for a period of time: Detecting the deceleration of the adjacent leading vehicle; and In response to detecting the deceleration of the nearby leading vehicle, decelerate to the lower deceleration target.

5. The method as described in claim 1, characterized in that: The second deceleration value is also based, at least in part, on a speed of the target vehicle; The speed of the adjacent leading vehicle; and The first deceleration value.

6. The method as described in claim 1, characterized in that: The deceleration value corresponds to the maximum deceleration value that the target vehicle can withstand without slipping.

7. The method as described in claim 1, characterized in that: The adjacent leading vehicle includes an optical output system configured to transmit information; and The target vehicle includes an optical sensing system configured to receive information transmitted by the optical output system.

8. The method as described in claim 7, characterized in that: The braking indication signal is transmitted via the optical output system of the nearby leading vehicle and received by the optical sensing system of the target vehicle.

9. The method as described in claim 7, characterized in that: The first deceleration value is transmitted as an coded signal via the optical output system of the adjacent leading vehicle.

10. A vehicle, characterized in that: include: A drive system configured to propel the vehicle; A braking system configured to decelerate the vehicle; A steering system configured to steer the vehicle; and A vehicle controller, the vehicle controller being configured to: Received from a nearby leading vehicle: A brake indication signal instructing the adjacent leading vehicle to initiate braking operation; and A first deceleration value, the first deceleration value indicating a deceleration rate of the adjacent leading vehicle; In response to receiving the braking indication signal: Determine a first distance relative to the nearest leading vehicle; A second deceleration value is determined at least in part based on the first distance, and the second deceleration value is configured to prevent the vehicle from colliding with the adjacent leading vehicle. Based on the determination that the second deceleration value is greater than or equal to an upper deceleration value, the braking system causes the vehicle to decelerate by the upper deceleration value; Based on the determination that the second deceleration value is less than the upper deceleration value and greater than the lower deceleration target, This causes the braking system to decelerate the vehicle by the second deceleration value; and Based on the determination that the second deceleration value is less than or equal to the lower deceleration target: Upon receiving the braking instruction signal, the drive system is caused to maintain the vehicle's speed for a period of time; and After maintaining the vehicle's speed for a period of time, the drive system is caused to decelerate to the lower deceleration target.

11. The vehicle as claimed in claim 10, characterized in that: The vehicle controller is also configured to determine the second deceleration value based at least in part on a speed of the vehicle and a speed of the adjacent leading vehicle.

12. The vehicle as claimed in claim 11, characterized in that: The vehicle controller is further configured to send deceleration information to a nearby following vehicle based on the determination that the second deceleration value is greater than or equal to the upper deceleration value, the deceleration information including: A second braking initiation signal; and The aforementioned deceleration value.

13. The vehicle as described in claim 12, characterized in that: The vehicle controller is further configured to send deceleration information to the nearby following vehicle based on the determination that the second deceleration value is less than the upper deceleration value, the deceleration information including: The second braking initiation signal; and The second deceleration value.

14. The vehicle as described in claim 13, characterized in that: The vehicle also includes: An optical output system configured to send the deceleration information to the nearby following vehicle; and An optical sensing system configured to receive the braking initiation signal and the first deceleration value.

15. A method for decelerating multiple vehicles along a road, characterized in that: include: At the first vehicle: Received from a nearby leading vehicle: First braking indication signal; and A first deceleration value, the first deceleration value indicating a deceleration rate of the adjacent leading vehicle; A second deceleration value is determined, the second deceleration value being configured to prevent the first vehicle from colliding with the adjacent leading vehicle; Based on the determination that the second deceleration value is greater than or equal to an upper deceleration value: Send to a second vehicle: A second brake indication signal indicating that the first vehicle has begun braking operation; and The aforementioned deceleration value; and Decelerate at the aforementioned deceleration value; and At the second vehicle: Received from the first vehicle: The second braking indication signal; and The aforementioned deceleration value; as well as In response to receiving the second braking indication signal: A third deceleration value is determined, the third deceleration value being configured to prevent the second vehicle from colliding with the first vehicle; The determination is based on the fact that the third deceleration value is less than the upper deceleration value and greater than the following deceleration target: Send to a nearby following vehicle: A third brake indication signal; and The third deceleration value; and Decelerate at the third deceleration value; and Based on the determination that the third deceleration value is less than or equal to the lower deceleration target: Maintain the speed of the second vehicle for a period of time; and After maintaining the speed of the second vehicle for a period of time, decelerate to the target deceleration.

16. The method as described in claim 15, characterized in that: It also includes, at the second vehicle: based on the determination that the third deceleration value is greater than or equal to the upper deceleration value: Send to the nearby following vehicle: The third braking indication signal; and The aforementioned deceleration value; and Decelerate at the aforementioned deceleration value.

17. A method for determining a deceleration rate of multiple vehicles in a row, characterized in that: include: At each corresponding vehicle in the row: Determine a corresponding distance relative to a corresponding neighboring leading vehicle; and A corresponding deceleration value is determined at least in part based on the corresponding distance; and At a vehicle in the row that is traveling at a speed and is associated with a first deceleration value: Received from a nearby leading vehicle: A brake indication signal instructing the adjacent leading vehicle to initiate braking operation; and A second deceleration value for an impending braking event of the adjacent leading vehicle; In response to receiving the braking indication signal: Based on the determination that the first deceleration value is greater than or equal to an upper deceleration value, the deceleration is reduced by the upper deceleration value; Based on the determination that the first deceleration value is less than the upper deceleration value and greater than the lower deceleration target, the deceleration is reduced by the first deceleration value; and Based on the determination that the first deceleration value is less than or equal to the lower deceleration target: After receiving the braking instruction signal, the vehicle is maintained at the speed for a period of time; and After maintaining the vehicle at the stated speed for a period of time, the vehicle decelerates towards the stated deceleration target.

18. The method as described in claim 17, characterized in that: The method further includes: determining a speed at each corresponding vehicle in the row for the corresponding adjacent leading vehicle; and The corresponding deceleration value is determined at least in part based on the speed of the corresponding adjacent leading vehicle.

19. The method as described in claim 17, characterized in that: Also includes: At the vehicle: After maintaining the vehicle at the speed: Detecting the deceleration of the adjacent leading vehicle; and The target decelerates as described below.

20. The method as described in claim 19, characterized in that: The deceleration value corresponds to the maximum deceleration value that the vehicle can withstand without slipping; and The deceleration target is 2.0 meters per square second or less.

21. A non-transitory computer-readable storage medium storing one or more programs, said one or more programs being executed by one or more processors of a computer system configured to decelerate a plurality of vehicles along a road, said one or more programs including instructions for performing the method according to any one of claims 1-9 or 15-16.

22. A computer program product comprising one or more programs configured to be executed by one or more processors of a computer system configured to decelerate a plurality of vehicles along a road, the one or more programs comprising instructions for performing the method according to any one of claims 1-9 or 15-16.

23. A non-transitory computer-readable storage medium storing one or more programs, said one or more programs being executed by one or more processors of a computer system configured to determine a deceleration rate of a plurality of vehicles in a row, said one or more programs including instructions for performing the method according to any one of claims 17-20.

24. A computer program product comprising one or more programs configured to be executed by one or more processors of a computer system configured to determine a deceleration rate of a plurality of vehicles in a row, the one or more programs comprising instructions for performing the method according to any one of claims 17-20.

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