High precision time of flight measurement system for industrial automation

Abstract

A system for tracking position of objects in an industrial environment includes an interrogator, a transponder, and a processor. The interrogator transmits a signal and provides a first reference signal corresponding to the transmitted signal. The transponder provides a response signal. The interrogator receives the response signal and provides a second reference signal corresponding to the response signal. The processor determines a location of either the interrogator or the transponder, relative to the other, based on the two reference signals.

What is claimed is: 
     
         1 . A system comprising:
 at least one first radio frequency transceiver configured to be mounted to a body part of a user;   at least one second radio frequency transceiver mounted to a portion of a robot;   a plurality of interrogators configured to determine a position of the at least one first radio frequency transceiver and configured to determine a position of the at least one second radio frequency transceiver; and   at least one controller configured to track, using the determined position of the at least one first radio frequency transceiver, movement of the body part of the user, and configured to track, using the determined position of the at least one second radio frequency transceiver, movement of the portion of the robot relative to the movement of the body part of the user.   
     
     
         2 . The system of  claim 1 , further comprising at least one feedback mechanism to provide feedback to the user about the position of the body part relative to the position of the portion of the robot. 
     
     
         3 . The system of  claim 2 , wherein the at least one feedback mechanism comprises haptic feedback. 
     
     
         4 . The system of  claim 2 , wherein the at least one feedback mechanism comprises at least one light emitting diode. 
     
     
         5 . The system of  claim 1 , wherein the at least one controller is configured to stop movement of the portion of the robot based on the determined position of the body part of the user relative to the determined position of the portion of the robot. 
     
     
         6 . The system of  claim 1 , wherein the at least one controller is configured to move the portion of the robot away from the body part of the user based on the determined position of the body part of the user relative to the determined position of the portion of the robot. 
     
     
         7 . The system of  claim 1 , wherein the at least one first radio frequency transceiver is affixed to a wristband configured to be worn by the user. 
     
     
         8 . The system of  claim 1 , wherein the at least one controller is configured to track, using the determined position of the at least one first radio frequency transceiver, movement of the body part of the user while picking items from, and/or placing items into, a plurality of bins. 
     
     
         9 . The system of  claim 8 , further comprising at least one feedback mechanism to provide feedback to the user in picking items from and/or placing items into the plurality of bins. 
     
     
         10 . The system of  claim 9 , wherein the at least one feedback mechanism is configured to signal to the user a correct one of the plurality of bins to pick an item from and/or to place an item into. 
     
     
         11 . The system of  claim 9 , wherein the at least one feedback mechanism is configured to signal to the user that an item has been correctly placed and/or correctly picked. 
     
     
         12 . The system of  claim 9 , wherein the at least one feedback mechanism is configured to signal to the user that an item has been incorrectly placed and/or incorrectly picked. 
     
     
         13 . The system of  claim 9 , wherein the at least one feedback mechanism provides an indication of an unsafe condition. 
     
     
         14 . A method comprising:
 determining a position of at least one first radio frequency transceiver mounted to a body part of a user using a plurality of interrogators;   determining a position of at least one second radio frequency transceiver mounted to a portion of a robot using the plurality of interrogators;   tracking, using the determined position of the at least one first radio frequency transceiver, movement of the body part of the user; and   tracking, using the determined position of the at least one second radio frequency transceiver, movement of the portion of the robot relative to the movement of the body part of the user.   
     
     
         15 . The method of  claim 14 , further comprising providing feedback to the user about the position of the body part relative to the position of the portion of the robot using at least one feedback mechanism. 
     
     
         16 . The method of  claim 14 , further comprising stopping movement of the portion of the robot based on the determined position of the body part of the user relative to the determined position of the portion of the robot. 
     
     
         17 . The method of  claim 14 , further comprising moving the portion of the robot away from the body part of the user based on the determined position of the body part of the user relative to the determined position of the portion of the robot. 
     
     
         18 . The method of  claim 14 , further comprising tracking, using the determined position of the at least one first radio frequency transceiver, movement of the body part of the user while picking items from, and/or placing items into, a plurality of bins. 
     
     
         19 . The method of  claim 18 , further comprising providing feedback to the user in picking items from and/or placing items into the plurality of bins using at least one feedback mechanism. 
     
     
         20 . The method of  claim 19 , further comprising signaling to the user a correct one of the plurality of bins to pick an item from and/or to place an item into using the at least one feedback mechanism.