Prodder with force feedback

Abstract

A detector for detecting detonatable devices such as land mines has a search head with a probe having a tip for placing beneath the surface of the ground. The probe tip ultrasonically provides an indication of the presence of a metal or plastic material. A force sensor coupled to the probe time provides an indication of force at the tip a it is placed beneath the ground surface. Therefore, before too much force is applied to the tip, a user is warned and accidental detonation may be prevented.

What is claimed is:  
     
       1. A detector for detecting detonatable devices or land mines, comprising: 
       a search head including a probe having a tip for placing beneath the surface of the ground, the probe tip for providing an indication of the presence of a metal or plastic material; and,  
       a force sensor other than an operator of the prodding rod for providing an indication of a force at the tip as it is placed beneath the ground surface, the indication independent of the indication of the presence of a metal or plastic material.  
     
     
       2. A prodding rod having a driver portion and a sensing end for contacting an object to be detected as defined in  claim 1  wherein the force sensor is positioned proximate the driver portion for sensing strain induced by the force applied at the sensing end of the rod. 
     
     
       3. A detector for detecting detonatable devices or land mines, as defined in  claim 1  wherein the search head includes ultrasonic detection means. 
     
     
       4. A detector for detecting detonatable devices or land mines, comprising: 
       a search head including a probe having a tip for placing beneath the surface of the ground, the probe tip for providing an indication of the presence of a metal or plastic material; and,  
       a force sensor other than an operator of the prodding rod for providing a signal that varies with a change in force applied to the tip.  
     
     
       5. A detector for detecting detonatable devices or land mines as defined in  claim 4  wherein said means is coupled to the probe tip. 
     
     
       6. A detector for detecting detonatable devices or land mines as defined in  claim 4  wherein said force is pressure. 
     
     
       7. A prodding rod having a driver portion and a sensing end for contacting an object to be detected, comprising: 
       means at or near the driver portion of the rod for imparting mechanical energy into the rod toward the sensing end, and for detecting a signal corresponding to a reflected wave, the signal containing information for determining a characteristic of the object;  
       a processor for processing the detected signal and for comparing the detected signal with a plurality of stored signals so as to categorize the object's material; and,  
       a force sensor other than an operator of the prodding rod for sensing the force applied to the object by the sensing end of the rod, a sensed force being other than directly related to the detected signal.  
     
     
       8. A prodding rod as defined in  claim 7  wherein the rod is non-magnetic, and where the rod includes means for indicating to a user, when excessive force is being applied. 
     
     
       9. A prodding rod as defined in  claim 8  wherein the means for indicating force provides a visual indication. 
     
     
       10. A prodding rod as defined in  claim 8 , wherein the means for indicating an excessive force includes a capacitive force sensor. 
     
     
       11. A prodding rod as defined in  claim 7 , including means for indicating to a user, when a variable force is being applied. 
     
     
       12. A prodding rod having a driver portion and a sensing end for contacting an object to be detected as defined in  claim 7  wherein the means at or near the driver portion of the rod for imparting mechanical energy into the rod comprises a transducer directly coupled at the driver end for electrically imparting mechanical energy into the rod which travels as a high frequency incident elastic wave from the driver end towards the sensing end and returns from the object as a reflected wave travelling towards the driver end. 
     
     
       13. A prodding rod having a driver portion and a sensing end for contacting an object to be detected as defined in  claim 7  wherein the sensed force applied to the object by the sensing end of the rod is uncorrelated with the detected signal. 
     
     
       14. A prodding rod having a driver portion and a sensing end for contacting an object to be detected as defined in  claim 7  wherein the force sensing means is positioned proximate the driver portion for sensing strain induced by the force applied at the sensing end of the rod. 
     
     
       15. A detector for detecting detonatable devices or land mines, comprising: 
       a search head including a probe having a tip for placing beneath the surface of the ground, the probe tip for providing an indication of the presence of a metal or plastic material; and,  
       a force sensor other than an operator of the prodding rod for providing an indication of a force at the tip as it is placed beneath the ground surface, the indication being one of a signal indicating a suitability of the force at the tip for providing an indication of the presence of a metal or plastic material, a signal related to the force at the tip for use in determining the presence of a metal or plastic material, and a signal based on a measurement of the force at the tip.