Title of Invention: VEHICLE SENSING SYSTEM USING DAISY CHAIN OF SENSORS
Abstract: 
A sensing system for a vehicle includes a plurality of sensors disposed at the vehicle. The plurality of sensors includes individual sensors connected to a vehicle network using a daisy chain topology. A control determines an address of the sensors and calibrates the sensors. The control, responsive to determination that an individual sensor is not the last sensor of a daisy chain of sensors, adjusts the internal electrical configuration to provide an open connection for another sensor. The control, responsive to determination that an individual sensor is the last sensor of the daisy chain of sensors, adjusts the internal electrical configuration to provide a termination configuration. The control, responsive to the outputs of the sensors, determines the presence of one or more objects exterior the vehicle and within the field of sensing of at least one of the sensors.

Detailed Description: 

CROSS REFERENCE TO RELATED APPLICATION
The present application claims the filing benefits of U.S. provisional application Ser. No. 62/361,586, filed Jul. 13, 2016, which is hereby incorporated herein by reference in its entirety.


FIELD OF THE INVENTION
The present invention relates generally to a vehicle sensing system for a vehicle and, more particularly, to a vehicle sensing system that utilizes a plurality of sensors at a vehicle to provide a field of sensing around the vehicle.
BACKGROUND OF THE INVENTION
Use of imaging sensors or ultrasonic sensors or radar sensors in vehicle sensing systems is common and known. Examples of such known systems are described in U.S. Pat. Nos. 8,013,780 and 5,949,331 and/or U.S. publication No. US-2010-0245066 and/or International Publication No. WO 2011/090484, which are hereby incorporated herein by reference in their entireties.
SUMMARY OF THE INVENTION
The present invention provides a driver assistance system or sensing system for a vehicle that utilizes one or more sensors (such as ultrasonic sensors or radar sensors or the like) disposed at the vehicle to sense respective regions exterior of the vehicle, with the sensors or sensor units comprising a plurality of sensors disposed at the vehicle. Outputs of the sensors are communicated to a control and, responsive to the outputs of the sensor unit, the control determines the presence of one or more objects exterior the vehicle and within the field of sensing of at least one of the sensors.
The system of the present invention solves concerns with respect to indistinguishable CAN or CAN FD knots or nodes in a vehicle network, which could be used for sensor chains or all other types of CAN knots, such as actuators or control devices. In order to solve such concerns, a termination and calibration process is provided.
These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing a standard CAN network topology;
FIG. 2 is a diagram showing a daisy chain sensor configuration in accordance with the present invention;
FIG. 3 is a diagram showing an initial mounting of a sensor;
FIG. 4 is a diagram showing reconfiguration of the connections based on sensor calibration;
FIG. 5 is a block diagram showing calibration of a sensor in accordance with the present invention;
FIG. 6 is a block diagram showing calibration of a sensor in the daisy chain of sensors of the present invention;
FIG. 7 is a plan view of a vehicle with daisy chains of sensors in accordance with the present invention; and
FIG. 8 is a diagram showing application of the daisy chain of sensors for an ultrasonic park assist (UPA) system.



DESCRIPTION OF THE PREFERRED EMBODIMENTS
A vehicle sensing system, such as a driving assist system, object detection system, parking assist system and/or alert system, operates to capture sensing data exterior of the vehicle and may process the captured data to detect objects at or near the vehicle and in the predicted path of the vehicle, such as to assist a driver of the vehicle in maneuvering the vehicle in a forward or rearward direction or to assist the driver in parking the vehicle in a parking space. The system includes a processor that is operable to receive sensing data from multiple sensors and to provide an output to a control that, responsive to the output, generates an alert or controls an accessory or system of the vehicle, or highlights or overlays an alert on a display screen (that may be displaying video images captured by a single rearward viewing camera or multiple cameras providing forward, side or 360 degree surround views of the area surrounding the vehicle during a reversing or low speed maneuver of the vehicle).
A vehicle network (such as a CAN bus or the like) uses network ID to receive and send messages in the network. The CAN (controller area network) database and message is predefined and pre-shared with suppliers to configure the vehicle network. Indistinguishable components need to be preconfigured. The system of the present invention avoids the need for preconfiguring indistinguishable components. A use case is, for example, CAN or CAN FD based automotive sensor chains, such as for ultrasonic park assist (UPA) sensors, Radar sensors and/or the like. The sensor knots in a CAN chain may also be of different (preconfigured and indistinguishable) types, such as control devices, output devices and actuators. An exemplary park assist system using the sensors and daisy chain topology of the present invention is shown in FIG. 7.
As shown in FIG. 1, a standard CAN network topology has each sensor connected to a CAN-Hi line and a CAN-Low line. A smart daisy chain sensor of the present invention is shown in FIG. 2. Switch configurations for an initial mounting of a sensor and for electrical reconfiguration based on sensor calibration are shown in FIGS. 3 and 4.
As shown in FIG. 5, a chain extension mechanism (where one or more sensors may be added to the chain of sensors at the vehicle and along and in communication with the communication network) is provided that uses an internal diagnostic routine that calibrates the sensor or sensors. Replacement of one or more sensors works in the same manner. The diagnostic trouble codes (DTCs) can be defined to identify sensor features in the chain.
Another chain extension mechanism is shown in FIG. 6, where calibration (learning the CAN ID) for sensor replacement is provided.
A CAN-based smart sensor system (such as for a UPA system of a vehicle) of the present invention is shown in FIG. 8. The system provides for removal of an existing UPA ECU and includes a daisy chain of CAN-based smart sensors. Optionally, SW decision blocks in other ECUs may be moved based on the system of FIG. 8. Although shown as applicable for a UPA system, the sensor system is applicable to other sensing systems as well.
Although described as having a plurality of ultrasonic sensors or sensor units disposed at the vehicle, the system of the present invention may utilize any suitable type of sensors, such as radar sensors, Lidar sensors, or the like. The means to adapt for the vehicle body response may be adjusted according to the type of sensors implemented in the sensing system.
Thus, the sensing system of the present invention is operable to calibrate a plurality of sensors for a sensing system for a vehicle. The plurality of sensors are configured to be disposed at a vehicle and electrically connected to a communication network of the vehicle, and the control is in communication with the communication network of the vehicle and is operable to process data sensed by the sensors when the sensors are connected to the communication network of the vehicle. When the system is initially installed or set up, an input may be provided to the control that is indicative of the number of sensors that are to be connected to the communication network as part of a daisy chain of sensors. When the individual sensors are connected to the communication network of the vehicle, the control may determine that the given connected sensor is connected to the communication network and calibrates the given connected sensor. The control may also determine an address or location of the sensor at the communication network and vehicle. The control, responsive to the known number of sensors to be connected and to the determined address of each sensor, determines whether an individual connected sensor is the last sensor of the daisy chain of sensors. If the individual sensor is determined to not be the last sensor of the daisy chain of sensors, the control adjusts the internal electrical configuration to provide an open connection for another sensor (and the control may search for another sensor connected to the communication network). If the individual sensor is determined to be the last sensor of the daisy chain of sensors, the control adjusts the internal electrical configuration to provide a termination configuration.
The sensing system of the present invention may utilize aspects of the systems described in U.S. Pat. Nos. 9,599,702; 9,575,160; 9,508,014; 8,013,780 and/or 5,949,331 and/or International Publication No. WO 2011/090484 and/or U.S. Publication No. US-2010-0245066 and/or U.S. patent application Ser. No. 15/619,627, filed Jun. 12, 2017 (Attorney Docket MAG04 P-3056R), Ser. No. 15/584,265, filed May 2, 2017 (Attorney Docket MAG04 P-3017R), Ser. No. 15/467,247, filed Mar. 23, 2017 (Attorney Docket MAG04 P-2978R), Ser. No. 15/446,220, filed Mar. 1, 2017 (Attorney Docket MAG04 P-2955), Ser. No. 15/420,238, filed Jan. 31, 2017 (Attorney Docket MAG04 P-2935R), and/or International PCT Application No. PCT/IB2017/054120, filed Jul. 7, 2017 (Attorney Docket MAG04 FP-3069R), which are hereby incorporated herein by reference in their entireties.
Changes and modifications in the specifically described embodiments can be carried out without departing from the principles of the invention, which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents.



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