Patent Publication Number: US-8991078-B1

Title: Pneumatic excavation system and method of use

Description:
1.0 CLAIM OF PRIORITY 
     The present application claims priority as a non-provisional of Ser. No. 61/881,896 filed on Sep. 24, 2013, and as a continuation of application Ser. No. 14/162,652 which is a continuation in part of application Ser. No. 13/094,136 filed on Apr. 26, 2011, and as a continuation of application Ser. No. 14/162,641 which is a continuation in part of application Ser. No. 13/094,136 filed on Apr. 26, 2011. These applications are herein incorporated by reference in their entirety. 
    
    
     2.0 TECHNICAL FIELD 
     The present invention relates to an excavating system and a method for using the excavation system. More specifically, this invention relates to a pneumatic excavating device that uses a supersonic or high-pressure pulsed air jet in combination with a low-pressure high velocity blower to excavate or dig in the ground. The device can be employed to excavate or unearth buried items such as but not limited to an improvised explosive device (IED). The system of the present invention can also be employed to remove an IED from the ground and/or to detonate an IED. 
     3.0 BACKGROUND 
     Pneumatic excavation systems of the prior air have previously employed high speed pulsed air jets such as Nathenson et al (U.S. Pat. No. 6,158,152). Nathenson et al (hereinafter “Nathenson”) employs a hand held or a vehicle-attached device that employs a high-pressure pulsed air jet to uncover buried unexploded ordinance. One distinct disadvantage of the system of Nathenson is that personnel operating the device are in close proximity to the unexploded ordnance. Nathenson does not teach employing a second or an additional air source for use in conjunction with a pulsed air jet for pneumatic excavation. The need remains for improvements to pneumatic excavation systems in a safe and effective manner. The present invention addresses the deficiencies in the prior art. 
     4.0 SUMMARY 
     One aspect of the present invention is to provide an excavation system that employs a high-pressure pulsed air jet and, optionally, a low-pressure high velocity air source. The low-pressure high velocity air source improves the digging capability of the device by assisting in the clearing or removal of the debris dislodged by the high-pressure pulsed air jet. The low-pressure air source also prevents the debris from falling back into the excavated site. 
     Another embodiment may be a kit that can retrofit an existing robot. This removes the need to have personnel in close proximity to the explosive device and provides existing robots with an alternative function. In another embodiment, an existing encrypted wireless communication channel is used in the operational control unit of the robot. This simplifies the integration of the excavating system to an existing robot. 
     Another embodiment provides a robot mounted excavation system that can be employed to perform other tasks such as operating a pneumatic tool. 
     In yet another embodiment, a method of excavation is disclosed. The method includes providing a robot with a nozzle for delivering a high-pressure pulsed air jet with a valve in communication with the nozzle, connecting the valve to a high pressure air source, optionally providing a low-pressure high velocity blower adjacent the valve, and using the high-pressure pulsed air jet optionally in combination with the high velocity blower during excavation. Other related method steps are also disclosed herein. 
     Other aspects of the invention are disclosed herein as discussed in the following Drawings and Detailed Description. 
    
    
     
       5.0 BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be better understood with reference to the following figures. The components within the figures are not necessarily to scale, emphasis instead being placed on clearly illustrating example aspects of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views and/or embodiments. It will be understood that certain components and details may not appear in the figures to assist in more clearly describing the invention. 
         FIG. 1  is an elevation view of a prior art robot. 
         FIG. 2A  is a right side view of the excavation system mounted on a robot. 
         FIG. 2B  is a left side view of the excavation system mounted on a robot. 
         FIG. 2C  is a side view of a variation of the system where a pneumatic tool can be operated by the system. 
         FIG. 3  is an elevation of the excavation system mounted a robot. 
         FIG. 4  is an elevation view of a controller for operating the robot and excavation system. 
         FIG. 5  is a right side view of the excavation system with the robot arm in the fully stowed position. 
         FIG. 6  is a left side view of the excavation system with the robot arm in a downward extended position. 
         FIG. 7  is a close up view of the robot arm with gripper and the evacuation valve of the excavation system. 
         FIG. 8  is an elevation view of the low-pressure high velocity blower. 
         FIG. 9  is a close up view of the robot arm with evacuation valve of with an attached pneumatic tool. 
         FIG. 10  is a partially exploded view of the excavation system with the evacuation valve and the high-pressure air tank removed. 
         FIG. 11  is a partially exploded view of the excavation system with the low-pressure high velocity air source removed. 
         FIG. 12  is a partially exploded view of the excavating system with the evacuation valve and the evacuation valve connected to a pneumatic tool. 
         FIG. 13  is a schematic of the pressure control module. 
         FIG. 14  is a close up view of the operation control unit modified for use with the excavating system. 
         FIG. 15A  is a close up view of the operation control unit modified for use with the excavating system. 
         FIG. 15B  is a map view of the operation control unit modified for use with the excavating system. 
         FIG. 15C  is a map view of the operation control unit from an existing robot without pneumatic excavating components. 
     
    
    
     6.0 DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Following is a non-limiting written description of example embodiments illustrating various aspects of the invention. These examples are provided to enable a person of ordinary skill in the art to practice the full scope of the invention without having to engage in an undue amount of experimentation. As will be apparent to persons skilled in the art, further modifications and adaptations can be made without departing from the spirit and scope of the invention, which is limited only by the claims. 
     In certain embodiments, the present invention may be used with the prior art robot  1  seen in  FIG. 1 . The robot  1  includes a mobile platform  2  with tracks  3 . The mobile platform  2  may include a rear mast  4  with a camera  5  mounted thereon. The mobile platform  2  includes with an upper arm  6  moveably connected to a lower arm  7 . The upper arm  6  can include a gripper  8  and may include one or more cameras  5  mounted thereon. The lower arm is moveably connected to the mobile platform  2 . The gripper  8  is pivotally attached to the end of the upper arm  6  by joint  9 . The connection between joint  9  and upper arm  6  allows rotation of joint  9  independently of upper arm  6 . 
     An excavation system  10  of the present invention incorporated on a prior art robot is shown in  FIGS. 2A and 2B . The excavation system  10  may includes two air sources. One is a high-pressure air tank  11  and the other is a low-pressure high velocity blower  12 . The air tank  11  is mounted on the mobile platform  2  and the high velocity blower  12  is mounted to the upper arm  6  of robot  1 . The upper arm  6  also includes an evacuation valve  13 . The system  10  includes a pressure control module  14  (PCM) mounted on the mobile platform  2  via PCM mounting bracket  15 . The PCM  14  is in fluid communication with the evacuation valve  13  and the air tank  11 . The PCM  14  regulates the high-pressure air (up to about 4500 PSI) in tank  11  to a pressure (about 300 PSI) that is employed by the evacuation valve  13 . The PCM  14  is adjustable such that the regulated pressure may be varied. It would be understood that other pressures may be used to successfully excavate items. For example, in soft sand a lower pressure might be sufficient and preferable so as to allow more high-pressure pulses from the air tank  11  without a need for a recharge. A lower pressure may be utilized when uncovering an IED with a pressure plate. Alternatively, if the excavation needs to penetrate clay or other more densely packed materials, a higher pressure may be needed. As discussed in more detail below, the amount of pressure regulation may be controlled by a remote operation control unit (OCU). 
     The air tank  11  and the PCM  14  may be mounted on different sides of the mobile platform  2  as seen in  FIG. 3 . This provides better balance and weight distribution to the mobile platform  2 . The air tank  11  is located above one track  3  and the PCM  14  is located over the second track  3 . An additional air tank may be employed to provide increased operation time of the excavation system  10 . The additional air tank may be stacked over the first tank (not shown). 
     The excavation system  10  may be employed to drive a pneumatic tool such as a cut-off tool  16  seen in  FIGS. 2C and 12 . The system  10  may be employed to operate any other pneumatic tool such as but not limited to a chisel (not shown). A pneumatic tool may be fluidly connected via a flexible air hose  17  to the evacuation valve  13  or another valve (not shown) in place of the evacuation valve  13 . The pneumatic tool may be attached to the gripper  8  as seen in  FIG. 9 . 
     The system includes an operation control unit (OCU)  18  as seen in  FIGS. 4 and 14 . An existing OCU  18  for the robot  1  is modified to control the excavation system  10 . The OCU  18  is modified to employ an existing encrypted wireless communication channel to control the excavation system. This eliminates the need of setting up additional or a separate encrypted communication channel to control the excavation system  10 . It also simplifies and speeds up the incorporation of the excavation system  10  to an existing robot  1 . 
     It should be noted that the prior art robot have a very high level of encryption because they are often used in an active battle zone. The encryption prevents the enemy from hi-jacking the robot, thus rendering it useless or worse turning the robot against the operator. Because of this high-level of encryption, it may not be economical or even possible to add new encrypted channels to an existing robot. In a retrofit kit, it may be preferably to re-purpose an existing channel to operate the excavation system described herein. This would maintain the operational integrity of the robot, and lowers costs. 
     The OCU  18  wirelessly communicates with the robot  1  and the excavation system  10  via encrypted channels to provide secure communication. The OCU  18  may employ multiple encrypted channels to control the various parts of the robot  1  and the excavation system  10 . The OCU  18  may include a video monitor  19  ( FIG. 4 ) for displaying real time video feed or images from the multiple cameras  5  mounted on robot  1 . The system  10  may be configured to allow a user to display multiple camera images on the monitor  19  at the same time. The excavation system  10  may be configured to allow the video monitor  19  to display air pressure data for various locations or parts of the system. The displayed pressures may include but are not limited to tank pressure, dome pressure (pressure in the dome of the first regulator valve), and jet pressure. A video pressure overlay unit (not shown) may be employed to provide the video monitor  19  with the pressure data on a real time basis by overlaying the pressure data on the encrypted video signal. Again, piggybacking on the existing encrypted transmissions between the robot and the OCU maintains operational integrity. 
     The upper and lower arms  6 ,  7  of the robot  1  can be moved to a variety of positions as seen in  FIGS. 3 ,  5 , and  6 .  FIG. 5  shows the upper arm  6  and the lower arm  7  (shown in dashed lines) in a fully stowed position where the upper and lower arms  6 ,  7  drop in between the air tank  11  and the PCM  14 .  FIG. 6  shows the upper arm  6  in a downwardly extended position where upper arm  6  could be in an excavation site in the ground. 
     A close up of the end of upper arm  6  is shown in  FIG. 7 . The evacuation valve  13  includes a first valve  20  and a second valve  21 , where the second valve  21  is remotely located from the first valve  20 . The second valve  21  controls the operation of the first valve  20  to produce the high-pressure pulsed air jet out of the nozzle  40  (shown in an exploded view). The nozzle  40  may be a De Laval nozzle such as the one disclosed in U.S. Pat. No. 522,066. A tube  22  connects the second valve  21  to the first valve  20  allowing the second valve  21  to control (i.e. the opening and closing) the first valve  20 . The second valve  21  may be a solenoid valve or a pilot valve. The second valve  21  can control the first valve  20  pneumatically via the tube  22 . The pneumatic control may be replaced with an electrical control or another suitable type of control. The gripper  8  may support the first valve  20 . The second valve  21  is remotely located from the first valve  20  to provide a narrower profile to the end of arm  6 . The second valve  21  is electrically connected to the PCM  14  by a suitable electric cable  23  or other connection mechanism (connection to PCM not shown). The high-pressure air jet has a pulse width or duration that is user selectable, i.e., it can be varied or controlled by the user. The duration may be in the order of about 30 to about 140 milliseconds. The high-pressure air jet has a delay between pulses that is also user selectable. The pulse delay may be in the order of about 0.25 seconds to about 2.3 seconds. 
     The second valve  21  is located within approximately 6 inches of the first valve  12 , so that the first valve  20  may be opened and shut quickly because it is necessary to conserve compressed air. The remote location of the second valve  21  allows the gripper  8  to operate freely, without compromising the ability of the gripper  8  to reach buried objects. 
     The low-pressure high velocity blower  12  is shown in  FIG. 8 . The high velocity blower  12  puts out a continuous flow of air. The high-pressure air jet puts out a pulsed or intermittent flow of air. The low-pressure high velocity air from the blower  12  improves the digging capability of the system  10  by assisting in the clearing or removal of the debris dislodged by the high-pressure pulsed air jet. The air from the blower  12  also prevents debris from falling back into the excavation site. The blower  12  preferably includes a bifurcated fan duct  24  with two air outlets  25  and an air inlet or intake (not shown). The air outlets  25  may be provided with mesh or screen covers (not shown). An air filter  26  is placed over the air inlet in the end of the bifurcated fan duct  24 . The air filter  26  seals and covers the air inlet and filters any air entering therein. The blower  12  includes an axial fan (not shown) located inside the inlet end of the bifurcated fan duct  24 . A fan control module  27  (FCM) is employed to control operation of the fan. The FCM  27  may be mounted on the outside of the bifurcated fan duct  24  or any other suitable location. The FCM  27  is preferably located in close proximity to the fan. The blower  12  has a fan duct mounting bracket  28  for securing the blower  12  to the upper arm  6  as seen in  FIGS. 10 and 11 . 
     Looking at  FIG. 10  the excavation system  10  is shown with the air tank  11  and its tank mounting bracket  29  removed from the mobile platform  2  and with the evacuation valve  13  removed from the gripper  8 . The FCM  27  is electrically connected to the PCM  14  via a suitable electric cable  23 . The blower  12  is positioned rearward of the gripper  8  to provide clearance between the gripper  8  and the blower  12 . This enables the end of upper arm  6  to rotate without interfering with the bifurcated fan duct  24 . 
     In  FIG. 13  a schematic of the PCM is shown in more detail. The PCM  14  includes the high-pressure input  105  from the from the high-pressure air tank  11  to a lower pressure outlet  110  supplied to the evacuation valve  13 . The PCM  14  may include a filter  115  two pressure regulator valves  120 ,  125  where the second valve  120  is employed to provide remote operation of the first pressure regulator valve  125 . The first pressure regulator valve  125  may be a dome-loaded high flow regulator valve. The second pressure regulator valve  120  is used to provide pressure to the dome input of the first regulator valve. The second pressure regulator valve  120  is connected to a solenoid valve  130  which is then connected to a pressure transducer  135 , and provides for remote control operation of the first pressure regulator valve  125  by varying the pressure provided to the dome input. The second pressure regulator valve  120  may also be connected to a solenoid valve  140  that vents the pressure to atmosphere, as well as a dome pressure relief valve  145  that vents to atmosphere. The first pressure regulator valve  125  may also be connected to a pressure relief valve  150  to vent to atmosphere. 
     The PCM  14  includes a high-pressure air inlet  105  and a lower pressure air outlet  110 . The air inlet  105  is connected to the air tank  11  by a suitable conduit or flexible hose and PCM may incorporate a high-pressure hose connector at the air inlet. The hose or conduit connecting the air tank  11  to PCM must be capable of withstanding the high-pressure air in tank  11 . The air outlet  110  is connected to the evacuation valve  13  and the PCM may incorporate a lower pressure hose connector such as but not limited to an AN-8 connector. The air outlet  110  is connected to the first valve  20  (of the evacuation valve  13 ) as seen in  FIGS. 7 and 10  by a suitable conduit or a flexible hose  17  (connection to air outlet not shown). The system  10  may be configured to allow a user to control and vary the air pressure exiting the air outlet during the operation of the excavation system  10  via the OCU  18 . The housing  30  of the PCM  14  may be a watertight case such as those sold under the PELICAN brand name. This is not intended to be limiting and any suitable housing  30  that will protect its internal components may enclose the PCM  14 . 
       FIG. 14  is a close up of the control panel  31  of the OCU  18 . The control panel  31  of the OCU  18  is shown including a lower arm control  32 , an upper arm control  33 , a mast control  34 , and a mobile platform drive control  35 . These controls are employed to move and operate their respective elements (i.e. the mobile platform drive control operates the mobile platform). The OCU  18  may also be provided with a control for the operation of a pneumatic tool (not shown). The OCU  18  may be provided with a selector switch  36  that would allow the air jet and high velocity blower  12  to operate at the same time or independently of each other. An on/off switch  37  incorporated in the OCU  18  as seen in  FIG. 14  may operate the high-pressure pulsed air jet and the low-pressure high velocity blower. These switches  36 ,  37  employ an existing encrypted communication channel or channels in the OCU  18  which is described in further detail below with reference to  FIGS. 15A-C . Other switches or controls to operate the excavation system  10  may be employed. 
       FIGS. 15A , B and B C further detail the repurposing of existing encrypted communication channels.  FIG. 15A  illustrates the OCU  31  of the robot that contains several switches.  FIG. 15B  illustrates a portion of the OCU  200  that includes the switches  36  and  37  that control the pneumatic excavation components, and a mobile platform drive control  35 . The OCU portion  200  also includes button  205  to actuate the gripper. In  FIG. 15C , the original OCU portion  210  of the robot is shown. The original robot does not have the pneumatic excavation components, and instead has switches  36   a  and  37   a  to control power to an LED and the intensity of the LED. The output for these switches on the robot have been connected to the pneumatic excavation components described herein. The new features include selector switch  36  (repurposed from switch  36   a ) which would allow the air jet and high velocity blower  12  to operate at the same time or independently of each other and on/off switch  37  (repurposed from switch  37   a ) to operate the high-pressure pulsed air jet and the low-pressure high velocity blower. Optionally, the OCU portion  210  may include a physical plate that lays over the existing OCU  31 , relabeling the switches so as to assist the robot operator. 
     The invention has been described in connection with specific embodiments that illustrate examples of the invention but do not limit its scope. Various example systems have been shown and described having various aspects and elements. Unless indicated otherwise, any feature, aspect or element of any of these systems may be removed from, added to, combined with or modified by any other feature, aspect or element of any of the systems. As will be apparent to persons skilled in the art, modifications and adaptations to the above-described systems and methods can be made without departing from the spirit and scope of the invention, which is defined only by the following claims. Moreover, the applicant expressly does not intend that the following claims “and the embodiments in the specification to be strictly coextensive.” Phillips v. AHW Corp.,  415  F.3d 1303, 1323 (Fed. Cir. 2005) (en banc).