Abstract:
A sensing system for providing vehicle automation. The system includes a master controller that is electrically connected to a receiver that has a transceiver that provides over-the-air communication to a plurality of wireless sonic sensors. The transceivers receive information from the plurality of wireless sonic sensors in order to automate the control of the vehicle to ensure the vehicle drives in a straight line.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates to a sensing system for following a string line or a surface. More specifically, this invention relates to a wireless mechanical string line following system for construction equipment. 
         [0002]    Often there is importance in having construction machines such as road paving machines be able to drive in a straight line and at a predetermined elevation. Currently string line sensors and surface sensors are placed far away from the body of the construction machine in close proximity to people and other moving construction moving vehicles. The cables for the string line sensors and the connector on the sensors themselves often get damaged because of the close proximity of traffic on a busy construction site. The sensor cables must be connected to the control system on the body of the machine which can be up to 30 feet away which exposes the cables to further damage. 
         [0003]    Thus, a need in the art exists for a way to eliminate these physical cables but still be able to accurately navigate the machines. Such elimination of cables would similarly minimize the risk of shutting down machine operation because of damage to such cable. In addition, eliminating the cable would provide additional safety for such road construction workers. 
         [0004]    Thus, a principal object of the present invention is to provide a sensing system for following a string line utilizing wireless technologies. 
         [0005]    Yet another object of the present invention is to eliminate risks associated with cables. 
         [0006]    These and other objects, features, and advantages will become apparent from the specification and claims. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    A sensing system for following a string line that includes a master controller and at least one receiver having a first transceiver in electric communication with the master controller. A plurality of wireless sonic sensors that are aligned along a string line or a surface are each in over-the-air communication with the first transceiver of the receiver in order to communicate data from the sonic sensors to the first transceiver. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a top schematic diagram of a sensing system; 
           [0009]      FIG. 2  is a protocol timing graph showing the movement of radio frequencies to and from transceivers of a receiver; and 
           [0010]      FIG. 3  is a schematic diagram of a sensing system for following a string line or a surface. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0011]    The figures show a sensing system  10  that includes a vehicle  12  that has a steering device  14  and optionally an elevation device  16  and associated valving  18 . The vehicle  12  in a preferred embodiment is a construction vehicle such as a paving machine, a skid steer loader, or the like. A master controller  20  having machine control software  21  is associated with the vehicle  12  by either being in the vehicle, on the vehicle, or the like. The machine control software  21  of the master controller  20  electrically controls the valving  18  and thus the steering device and elevation device  14  and  16  for automated control of the vehicle  12 . The master controller  20  additionally has a user interface  22  that allows for manual operation of functions of the system  10 . 
         [0012]    First and second receivers  24  and  26  are electrically connected and in communication with the master controller  22  via software  28  or a CAN bus that provide CAN messaging between the receivers  24 ,  26  and master controller  20 . The software  28  in one embodiment includes application programming interface that interfaces with the software of the receivers to send an electronic signal containing information to the machine control software. Each receiver  24 ,  26  has first and second transceivers  30  and  32  that in a preferred embodiment are 802.15.4 wireless radio links for bi-directional communication. By having two transceivers the sensor system band width is increased and additionally allows for active scanning of radio channel activity. 
         [0013]    A plurality of wireless sonic sensors  34  are aligned along a string line  36  or a surface to ensure the sonic sensors  34  are aligned. Each of the plurality of wireless sonic sensors  34  has a wand or transceiver  38  that is preferably 802.15.4 wireless radio link. In this manner the transceiver  38  is in over-the-air communication with a transceiver  30  or  32  of the receivers  24  or  26 . In addition the plurality of wireless sensors  34  each have a RFID reader  40  that is able to read an RFID tag  42  located on a mounting bracket  44  of a sonic sensor  34  in order to uniquely identify the sensor to the master controller  20 . 
         [0014]    In operation, the first transceiver  30  of the first and second receivers  24 ,  26  transmits a time triggered protocol beacon at time=zero, TO, as shown in  FIG. 2 . Each of the plurality of sonic sensors  34  responds with its positioning and status data in its respective time slot. Simultaneously the second transceiver  32  of the receivers  24 ,  26  collects wireless sensor data and scans all radio channels and determines the channel with the least amount of traffic available. At this time the receivers  24 ,  26  communicate with the plurality of sonic sensors  34  to proactively command the sensors  34  to change to the radio channel with the least amount of traffic. The receivers  24 ,  26  also sort the sensor data into a CAN message  28  that is then transmitted over a machine control CAN bus to the master controller  20 . Based on this communicated data the master controller  20  then selectively actuates the valving  18  of the vehicle  12  in order to control the steering device and elevation device  14 ,  16  to thus control the steering and elevation of the vehicle  12 . Simultaneously the master controller  20  polls the receiver status, all sensors status, and can manually set the channels through the user interface  22 . 
         [0015]    Thus provided is a sensing system  10  that can be utilized in order to control the elevation and steering for a vehicle  12  such as a road construction machine for road paving. The transceivers  36  or wands attached to the plurality of sonic sensors  34  sense the machine or vehicle  12  position versus the string line  36  position to provide control input to the elevation or steering control loop of the vehicle  12 . 
         [0016]    Thus, wireless mechanical string line wand sensors are provided. The multiple wireless sonic sensors  34  can be read by the receivers  24 ,  26  at a very high data rate through the time triggered custom wireless protocol. Additionally, provided is the ability to actively switch to low traffic channels in a direct sequence spread spectrum (DSSS) and the use of an RFID reader  40  in order to read the RFID tag  42  to provide for automated machine sensor location. Thus, at the very least all of the stated objectives have been met. 
         [0017]    It will be appreciated by those skilled in the art that other various modifications could be made to the device without departing from the spirit and scope of this invention. All such modifications and changes fall within the scope of the claims and are intended to be covered thereby.