Patent Description:
Modern vehicles may have various types of automated controls to assist a driver of the vehicle. One type of automated vehicle control system is an adaptive cruise control system. Adaptive cruise control systems provide additional functionality over traditional cruise control systems. For example, an adaptive cruise control ("ACC") system may maintain a desired speed for the vehicle until the ACC system detects a vehicle travelling at a slower speed in front of the vehicle. An adaptive cruise control system may also adjust the speed of the vehicle based on changes or features of a roadway being traversed by the vehicle. However, in these examples, the adaptive cruise control systems adjust the speed without considering the effect on other vehicles on the roadway. In particular, changes in speed of the vehicle may be somewhat disruptive to traffic flow and other drivers.

<CIT> relates to a method and system for determining a longitudinal dynamics driving strategy for a vehicle.

<CIT> relates to a vehicular travel control device designed for enhancing fuel efficiency while minimizing disruption to the surrounding environment.

<CIT> relates to a method for operating a driver assistance system in a vehicle, designed to support the driver during coasting maneuvers.

The aim of the present invention is to provide an adaptative cruise control system for a host vehicle according to claim <NUM> and a method of adaptively controlling a host vehicle according to claim <NUM>.

Other aspects and embodiments will become apparent by consideration of the detailed description and accompanying drawings.

Before any embodiments are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings.

A plurality of hardware and software based devices, as well as a plurality of different structural components may be used to implement various embodiments. In addition, embodiments may include hardware, software, and electronic components or modules that, for purposes of discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware. However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, the electronic based aspects of the invention may be implemented in software (for example, stored on non-transitory computer-readable medium) executable by one or more processors. For example, "control units" and "controllers" described in the specification can include one or more processors, one or more memory modules including non-transitory computer-readable medium, one or more input/output interfaces, and various connections (for example, a system bus) connecting the components.

<FIG> illustrates a host vehicle <NUM> equipped with an adaptive cruise control system <NUM> according to one embodiment. In the example illustrated, the adaptive cruise control system <NUM> is constructed of multiple components including a controller <NUM>, a speed control <NUM>, a user interface <NUM>, a navigation system <NUM>, a rearward facing sensor <NUM>, and a front sensor <NUM>. The controller <NUM> is communicatively coupled to the speed control <NUM>, the user interface <NUM>, the navigation system <NUM>, the rearward facing sensor <NUM>, and the front sensor <NUM> via various wired or wireless connections. For example, in some embodiments, the controller <NUM> is directly coupled via a dedicated wire to each of the above-listed components of the adaptive cruise control system <NUM>. In other embodiments, the controller <NUM> is communicatively coupled to one or more of the components via a shared communication link such as a vehicle communication bus (for example, a controller area network (CAN) bus) or a vehicle network (for example, a wireless connection).

The components of the adaptive cruise control system <NUM> may be of various constructions and types. For example, in some embodiments, the speed control <NUM> may be an electronically controlled device (for example, a throttle) for controlling power delivered to an engine of the host vehicle <NUM>. In some embodiments, the speed control <NUM> also includes automatic braking controls. In another example, the user interface <NUM> includes hardware and may also include software configured to provide a human machine interface (HMI). This may include buttons, panels, dials, lights, displays, and the like, which provide input and output functionality between the controller <NUM> and a driver of the host vehicle <NUM>. The user interface <NUM> may include one or more selectable inputs (for example, buttons or selectable icons on a display) to change modes of operation of the host vehicle <NUM> including, for example, one or more inputs to activate and deactivate adaptive cruise control or to set a desired cruise control speed. The user interface <NUM> may also include an indicator (for example, a light, an icon, an audible alarm, haptic feedback, and the like) for providing various indications to a driver of the host vehicle <NUM>.

In another example, the navigation system <NUM> includes additional input/output functionality for the adaptive cruise control system <NUM>. The navigation system <NUM> may gather information via a global positioning system (GPS), a remote information server, an internal database, and the like. The information may include road conditions, traffic conditions, or both. For example, information about current and upcoming road conditions and traffic conditions may be generated externally or internally for the controller <NUM>. The road conditions may include upcoming declining or inclining road slope, an upcoming curve in the road, an upcoming decrease or increase in a speed limit, and the like.

The controller <NUM> uses the road conditions and the traffic conditions, at least in part, to determine when to enable a coasting mode of operation (hereafter "coasting mode"). In one example, road slope information allows the controller <NUM> to predict upcoming changes in a pitch angle of the host vehicle <NUM> based on the upcoming road slope. Road curve information allows the controller <NUM> to predict upcoming changes in a yaw angle and lateral acceleration of the host vehicle <NUM>. As a consequence, the road conditions enable the controller <NUM> to predict future power requirements for the host vehicle <NUM>. For example, the controller <NUM> may predict the power output to the engine necessary to maintain a range of speed set by the adaptive cruise control system <NUM> based on the road conditions. Accordingly, the controller <NUM> may determine when the host vehicle <NUM> will require less power and enable, activate, or transition to the coasting mode in anticipation of and to take advantage of the upcoming reduction in power. When the coasting mode is enabled or activated, the controller <NUM> may remove or reduce power output to the engine. However, even when the coasting mode is enabled, in some embodiments, the controller <NUM>, based on information received from the rearward facing sensor <NUM>, adjusts the timing of coasting (for example, the duration of coasting), the amount of coasting (for example, an allowable speed range), and deactivation of coasting as discussed in more detail below. As a consequence, the controller <NUM> may reduce power consumption of the vehicle where appropriate to save fuel.

In yet another example, the rearward facing sensor <NUM> may be mounted on a rear of the host vehicle <NUM> and be positioned with a field-of-view facing rearward from the host vehicle <NUM>. In one example, the rearward facing sensor <NUM> may be externally mounted to a frame of the host vehicle <NUM>. In another example, the rearward facing sensor <NUM> may be internally mounted within the host vehicle <NUM>. In other embodiments, the rearward facing sensor <NUM> may be mounted on a side of the host vehicle (for example, on a side mirror) and directed towards the rear of the host vehicle <NUM>. In some embodiments, the rearward facing sensor <NUM> includes radio detection and ranging (RADAR) or light detection and ranging (LIDAR) components and functionality. In other embodiments, the rearward facing sensor <NUM> may include ultrasonic detection and functionality. In these embodiments, the rearward facing sensor <NUM> and the front sensor <NUM> are configured to transmit signals from the host vehicle <NUM> and to receive reflected signals indicative of a distance and a relative speed between the host vehicle <NUM> and a target vehicle (illustrated in <FIG>). In yet other embodiments, the rearward facing sensor <NUM> receives transmissions (for example, radio frequency signals) from other vehicles indicative of distance, relative speed, location, and the like of the other vehicles rather than actively sensing these parameters. For example, in these embodiments, the "rearward facing sensor" may use vehicle-to-vehicle (V2V) technology to obtain at least some of the parameters used in the methods and systems described herein. In yet other embodiments, the rearward facing sensor <NUM> is a camera configured to capture images of other vehicles located behind the host vehicle <NUM>. In these embodiments, various image or video processing equipment may determine distance, relative speed, location, and the like of other vehicles located behind the host vehicle <NUM>. Similarly, the front sensor <NUM> may include one or more of the technologies described above with reference to the rear sensor <NUM>.

Each of the above-listed components of the adaptive cruise control system <NUM> may include dedicated processing circuitry including an electronic processor and memory for receiving, processing, and transmitting data. Each of the components of the adaptive cruise control system <NUM> may communicate with the controller <NUM> using a predetermined communication protocol. The embodiment illustrated in <FIG> provides but one example of the components and connections of the adaptive cruise control system <NUM>. However, these components and connections may be constructed in other ways than those illustrated and described herein.

<FIG> is a block diagram of the controller <NUM> of the adaptive cruise control system <NUM> according to one embodiment. The controller <NUM> includes a plurality of electrical and electronic components that provide power, operation control, and protection to the components and modules within the controller <NUM>. The controller <NUM> includes, among other things, an electronic processor <NUM> (such as a programmable electronic microprocessor, microcontroller, or similar device), a memory <NUM> (for example, non-transitory, machine readable memory), and an input/output interface <NUM>. In other embodiments, the controller <NUM> includes additional, fewer, or different components. The controller <NUM> may be implemented in several independent controllers (for example, programmable electronic control units) each configured to perform specific functions or sub-functions. Additionally, the controller <NUM> may contain sub-modules that include additional electronic processors, memory, or application specific integrated circuits (ASICs) for handling input/output functions, processing of signals, and application of the methods listed below.

The controller <NUM> and associated systems are configured to implement, among other things, processes and methods described herein. For example, the electronic processor <NUM> is communicatively coupled to the memory <NUM> and executes instructions which are capable of being stored on the memory <NUM>. The electronic processor <NUM> is configured to retrieve from memory <NUM> and execute instructions related the methods of operation of the adaptive cruise control system <NUM>. In some embodiments, the input/output interface <NUM> includes drivers, relays, switches, and the like to operate the speed control <NUM> based on instructions from the electronic processor <NUM>. In some embodiments, the input/output interface <NUM> communicates with other vehicle controllers or systems by means of a protocol such as J1939 or CAN bus. In other embodiments, the input/output interface <NUM> communicates under other suitable protocols depending on the needs of the specific application.

<FIG> illustrates a flowchart of a method <NUM> of operating the host vehicle <NUM> with the adaptive cruise control system <NUM> according to one embodiment. The method <NUM> includes receiving at least one parameter indicative of a road condition or a traffic condition (block <NUM>). As described above, the at least one parameter may be generated by the navigation system <NUM> based on a current location of the host vehicle <NUM>. In some embodiments, the at least one parameter is sensed, at least in part, by the front sensor <NUM>. For example, the front sensor <NUM> may generate road slope information, road curvature information, traffic condition information, or any combination of the foregoing. In some embodiments, the road conditions and traffic conditions may be sensed or otherwise determined by the navigation system <NUM> and the front sensor <NUM> acting alone or in combination. Based on the at least one parameter, the controller <NUM> sets a coasting mode of the adaptive cruise control system <NUM> to active or inactive (block <NUM>). The controller <NUM> receives a signal from the rearward facing sensor <NUM> indicative of the presence, or lack thereof, of a target vehicle positioned behind the host vehicle <NUM> (block <NUM>). When the signal from the rearward facing sensor <NUM> detects the target vehicle, the controller <NUM> may restrict the coasting mode (block <NUM>). Conversely, when the signal from the rearward facing sensor <NUM> does not detect a target vehicle and when the coasting mode is active, the controller <NUM> performs coasting via the speed control <NUM> without restriction (block <NUM>). In some embodiments, more than just the detection of the target vehicle occurs before the controller <NUM> restricts the coasting mode. For example, detection of a particular distance or speed of the target vehicle may be necessary before any restriction is applied by the controller <NUM>, as discussed below.

The order of the steps of the method <NUM> is not critical to the performance of the method <NUM>. The steps of the method <NUM> may be performed in orders other than those illustrated or the steps may be performed simultaneously. In addition, the steps of the method <NUM> may be performed rapidly and in repetition. For example, particular steps of the method <NUM> may be continuously performed during general operation of the host vehicle <NUM> or only while the adaptive cruise control system <NUM> is active.

<FIG> illustrate driving scenarios in which adaptive cruise control is actively being performed by the controller <NUM>. In the examples illustrated, a target vehicle <NUM> is positioned behind and in a same lane as the host vehicle <NUM>. The rearward facing sensor <NUM> has a range <NUM> that extends rearward from the host vehicle <NUM>. The controller <NUM> receives the signal from the rearward facing sensor <NUM> indicative of the presence of the target vehicle <NUM>. As described in block <NUM> of method <NUM>, the controller <NUM> restricts the coasting mode when the signal from the rearward facing sensor <NUM> detects a target vehicle positioned behind the host vehicle <NUM>. Restricting the coasting mode may be performed in various ways. For example, in some embodiments, when the rearward facing sensor <NUM> detects the presence of the target vehicle <NUM>, the controller <NUM> restricts the coasting mode of the adaptive cruise control system <NUM>. In other embodiments, the controller <NUM> restricts the coasting mode based on detection of the target vehicle <NUM> only when certain additional conditions occur.

In some embodiments, the controller <NUM> determines a distance <NUM> between the host vehicle <NUM> and the target vehicle <NUM> based on the signal from the rearward facing sensor <NUM>. As illustrated in <FIG>, when the distance <NUM> is greater than a predetermined distance threshold <NUM>, the controller <NUM> classifies the target vehicle <NUM> as "far" from the host vehicle <NUM>. Conversely, as illustrated in <FIG>, when the target vehicle <NUM> is less than the predetermined distance threshold <NUM> (for example, the predetermined distance threshold may be approximately <NUM> car lengths), the controller <NUM> classifies the target vehicle <NUM> as "near" to the host vehicle <NUM>. In other words, the target vehicle <NUM> is "near" to the host vehicle <NUM> when the target vehicle <NUM> is close enough to the host vehicle <NUM> such that activation of coasting by the host vehicle <NUM> will require sudden braking by the target vehicle <NUM>. Based on the classification of the distance <NUM>, the controller <NUM> may adjust the adaptive cruise control system <NUM> by activating coasting, deactivating coasting, or allowing coasting within predefined limits.

In some cases, restricting the coasting mode based on the distance <NUM> includes disabling coasting mode. In such cases, whenever the target vehicle <NUM> is "near" to the host vehicle <NUM>, the controller <NUM> ceases to perform coasting mode at least until the target vehicle <NUM> is no longer classified as "near" to the host vehicle <NUM>. In other embodiments, the controller <NUM> ceases to perform coasting as soon as the target vehicle <NUM> is detected by the rearward facing sensor <NUM>. This may occur even when the controller <NUM> classifies the target vehicle <NUM> as "far" from the host vehicle <NUM>.

In other embodiments, the controller <NUM> restricts the coasting mode by setting predefined limits to the coasting mode. This may occur when the target vehicle is "near" to or "far" from the host vehicle <NUM>. For example, the controller <NUM> may have a first set of predefined limits when the target vehicle <NUM> is "near" to the host vehicle <NUM> and a second set of predefined limits when the target vehicle <NUM> is "far" from the host vehicle <NUM>. In this case, the first set of predefined limits may restrict coasting more than the second set of predefined limits.

The predefined limits may influence the behavior of the adaptive cruise control system <NUM> in various ways. For example, the controller <NUM> may set the predefined limits by setting a minimum speed of the host vehicle <NUM>. The minimum speed may be based on the road conditions or the traffic information. As a consequence, the minimum speed sets a limit on the amount of coasting that is available. For example, when the host vehicle <NUM> slows from coasting to the minimum speed, the controller <NUM> maintains the host vehicle <NUM> at the minimum speed via the speed control <NUM> by providing some power to the engine of the host vehicle <NUM>.

The predefined limits may also restrict a period of time available for coasting or of initialization of coasting. For example, the controller <NUM> may restrict coasting by performing coasting for shorter periods of time or may delay initialization of the coasting mode. For example, when the host vehicle <NUM> is approaching a downhill slope (for example, just prior to cresting a hill) and when coasting mode is enabled, the controller <NUM> may anticipate an upcoming reduction in power to the engine. In this example, when no target vehicle <NUM> is detected, the controller <NUM> may set the host vehicle <NUM> to coast without restriction. However, when the target vehicle <NUM> is "near" to the host vehicle <NUM>, the controller <NUM> may activate the coasting mode later in time or for a shorter period of time based on the first set of predefined limits. Similarly, when the target vehicle <NUM> is classified as "far" from the host vehicle <NUM>, the controller <NUM> may activate the coasting mode later in time or for a shorter period of time based on the second set of predefined limits.

According to the invention, the controller <NUM> restricts the coasting mode based on a relative speed between the host vehicle <NUM> and the target vehicle <NUM>. The controller <NUM> determines a speed of the target vehicle <NUM> relative to the host vehicle <NUM> based on the signal received from the rearward facing sensor <NUM>. This may include simply determining whether the distance <NUM> is increasing or decreasing. Based on the determination, the controller <NUM> classifies the target vehicle <NUM> as "approaching," "receding," or "constant. " To classify the target vehicle <NUM>, the controller <NUM> may compare the relative speed of the target vehicle <NUM> to a predetermined speed threshold (not shown). For example, the controller <NUM> may classify the target vehicle <NUM> as "approaching" when the relative speed is greater than the predetermined speed threshold, as "receding" when the relative speed is lower than the predetermined speed threshold, and as "constant" when the relative speed is approximately zero (for example, less than <NUM> miles per hour). In some embodiments, the controller <NUM> may classify the target vehicle <NUM> as "fast approaching" (for example, approaching the host vehicle <NUM> at greater than <NUM> miles per hour).

Similar to adjusting the adaptive cruise control system <NUM> based on distance classifications, the controller <NUM> may adjust the adaptive cruise control system <NUM> by activating coasting, deactivating coasting, or allowing coasting within predefined limits based on speed classifications.

In some cases, restricting the coasting mode based on the relative speed of the target vehicle <NUM> includes disabling coasting mode. In such cases, whenever the target vehicle <NUM> is "approaching" the host vehicle <NUM>, the controller <NUM> ceases to perform coasting mode at least until the target vehicle <NUM> is no longer classified as "approaching" the host vehicle <NUM> (for example, when the target vehicle <NUM> changes lanes). In other embodiments, the controller <NUM> ceases to perform coasting when the target vehicle <NUM> is classified as "constant" or only when the target vehicle <NUM> is classified as "fast approaching.

The controller <NUM> restricts the coasting mode by setting predefined limits to the coasting mode based on the relative speed. This may occur when the target vehicle <NUM> is "approaching," "fast approaching," or "constant" from the host vehicle <NUM>. According to the invention, the controller <NUM> has a first set of predefined limits when the target vehicle <NUM> is "approaching" the host vehicle <NUM> and a second set of predefined limits when the target vehicle <NUM> is "constant" from the host vehicle <NUM>. In this case, the first set of predefined limits restricts coasting more than the second set of predefined limits. In addition, the host vehicle <NUM> may have a third set of predefined limits when the target vehicle <NUM> is "fast approaching" that would restrict coasting more than either the first set of predefined limits or the second set of predefined limits. Similar to the above, the controller <NUM> may restrict coasting by performing coasting for shorter periods of time or may delay initialization of the coasting mode.

The controller <NUM> may also adjust the adaptive cruise control system <NUM> based on both the distance <NUM> and the relative speed of the target vehicle <NUM>. In this case, the controller <NUM> may only disable the coasting mode when the target vehicle <NUM> is classified as both "near" and "approaching. " In addition, the controller <NUM> may set predefined limits to the coasting mode based on the combination of the distance <NUM> and the relative speed of the target vehicle <NUM>. For example, the controller <NUM> may combine the distance <NUM> and the relative speed of the target vehicle <NUM> into a risk assessment value. In this case, when the risk assessment value is greater than a first risk threshold, the controller <NUM> may set predefined limits and when the risk assessment value is greater than a second risk threshold, the controller <NUM> may disable coasting.

In some embodiments, the controller <NUM> may adjust the predefined limits of the coasting mode over a relatively continuous range based on the risk assessment value. In these embodiments, the controller <NUM> gradually reduces the predefined limits as the risk assessment value increases.

Claim 1:
An adaptive cruise control system (<NUM>) for a host vehicle (<NUM>), the system comprising:
a rearward facing sensor (<NUM>);
a speed control (<NUM>); and
a controller (<NUM>) including an electronic processor, the controller (<NUM>) communicatively coupled to the rearward facing sensor (<NUM>) and the speed control (<NUM>), wherein the controller (<NUM>) is configured to:
receive at least one parameter indicative of at least one from the group consisting of a road condition and a traffic condition;
activate a coasting mode based on the at least one parameter;
receive a signal from the rearward facing sensor (<NUM>) indicative of a presence of a target vehicle positioned behind the host vehicle (<NUM>);
restrict the coasting mode when the signal from the rearward facing sensor (<NUM>) detects the target vehicle (<NUM>) positioned behind the host vehicle (<NUM>), wherein the controller (<NUM>) is further configured to:
determine a speed of the target vehicle relative to the host vehicle and to classify the target vehicle as approaching the host vehicle (<NUM>) or receding from the host vehicle (<NUM>) or constant based on a predetermined speed threshold,
set a first set of predetermined limits when the target vehicle is classified as approaching and set a second set of predetermined limits when the target vehicle is classified as constant, wherein the first set of predetermined limits restricts coasting more than the second set of predetermined limits; and
perform coasting via the speed control when the signal from the rearward facing sensor (<NUM>) does not detect the target vehicle (<NUM>) positioned behind the host vehicle (<NUM>) and when the coasting mode is active.