Amphibious robotic device

Abstract

A robotic device for navigating in at least a liquid medium, includes a legged propulsion system having a series of legs external of a body of the robotic device, each of the legs being independently driven and mounted to the body for pivotal movement about a respective transverse axis. The legs oscillating relative to the body about the respective transverse axis such that interaction between the legs and the liquid medium produces propulsive forces that displace the robotic device within the liquid medium. A control system is operatively connected to the legged propulsion system for autonomous control and operation of the robotic device based on information received from at least one sensor providing data about an environment of the device.

1 . A robotic device for navigating in at least a liquid medium, the robotic device comprising:
 a legged propulsion system having a series of legs external of a body of the robotic device, each of the legs being independently driven and mounted to the body for pivotal movement about a respective transverse axis, each of the legs being operable to at least oscillate relative to the body about the respective transverse axis such that interaction between the legs and the liquid medium produces propulsive forces that displace the robotic device within the liquid medium; and   a control system operatively connected to the legged propulsion system for autonomous control and operation of the robotic device based on information received from at least one sensor providing data about an environment of the device, the control system using data from the at least one sensor to determine a desired motion of the robotic device and a corresponding required leg motion of each of the legs to produce the desired motion, and the control system autonomously actuating each of the legs of the legged propulsion system in accordance with the corresponding required leg motion.   
   
   
       2 . The robotic device according to  claim 1 , wherein the desired motion includes a series of at least two consecutive steps, each step including one of movement in at least one of six degrees of freedom and station keeping. 
   
   
       3 . The robotic device according to  claim 1 , wherein the at least one sensor includes a visual sensor retrieving an image of an environment of the device, the control system determining a presence of an object of a given type in the image, determining an identity of the object from a given list of possible objects of the given type, and determining the desired motion associated with the identity of the object in the list. 
   
   
       4 . The robotic device according to  claim 1 , wherein the at least one sensor includes a visual sensor retrieving an image of an environment of the device, the control system determining a presence of an object of a given type in the image, determining a position of the object on the image and comparing the position to a desired position, and determining the desired motion of the device such as to change to position to correspond to the desired position. 
   
   
       5 . The robotic device according to  claim 1 , wherein the control system includes a motion calculator having at least one angular controller which calculates a required angular displacement necessary to achieve said desired motion. 
   
   
       6 . The robotic device according to  claim 5 , wherein the angular control includes a yaw controller calculating a required yaw of the device, a pitch controller calculating a required pitch of the device and a roll controller calculating a required roll of the device, the desired motion including at least one of the required yaw, the required pitch and the required roll. 
   
   
       7 . The robotic device according to  claim 1 , wherein each of the legs is also operable to rotate about the respective transverse axis such that interaction between the legs and a solid medium allows the robotic device to move on the solid medium, thereby making the robotic device amphibious. 
   
   
       8 . The robotic device according to  claim 1 , wherein each of the legs defines at least two members pivotally interconnected to relatively pivot about a pivot axis parallel to the respective transverse axis. 
   
   
       9 . An amphibious robotic device comprising:
 a legged propulsion system having a series of legs, each of said legs being driven by an actuator and mounted for pivotal movement about a respective transverse axis in one of at least a swimming mode and a walking mode, said legs being configured to pivotally oscillate relative to the transverse axis in said swimming mode when the device is in a liquid medium such that interaction between said legs and the liquid medium provides propulsive forces that displace the vehicle body within the liquid medium, said legs being configured to rotate relative to the transverse axis in said walking mode when the device is on a solid medium such that interaction between said legs and the solid medium provides propulsive forces that displace the vehicle body in a desired direction on the solid medium; and   a control system having at least one sensor operable to autonomously detect with which of the liquid medium and the solid medium the robotic device is interacting and a leg controller synchronously operating said legs in either one of the swimming mode and the walking mode based on the detected medium.   
   
   
       10 . The amphibious robotic device according to  claim 9 , wherein each leg defines at least two members pivotally interconnected to relatively pivot about a pivot axis parallel to the respective transverse axis. 
   
   
       11 . The amphibious robotic device according to  claim 10 , wherein each leg includes an elastic material extending through the members and providing resistance to a relative pivoting motion of the members about the pivot axis. 
   
   
       12 . The amphibious robotic device according to  claim 11 , wherein the resistance to the relative pivoting motion of the members increases as the members pivot away from an aligned position. 
   
   
       13 . The amphibious robotic device according to  claim 9 , wherein the control system is operatively connected to the legged propulsion system for autonomous control and operation of the robotic device based on information received from the at least one sensor, the control system using data from the at least one sensor to determine a desired motion of the robotic device and a corresponding required leg motion of each of the legs to produce the desired motion, and the control system autonomously actuating each of the legs of the legged propulsion system in accordance with the corresponding required leg motion. 
   
   
       14 . The amphibious robotic device according to  claim 13 , wherein the desired motion includes a series of at least two consecutive steps, each step including one of movement in at least one of six degrees of freedom and station keeping. 
   
   
       15 . The amphibious robotic device according to  claim 13 , wherein the control system includes a motion calculator having at least one angular controller which calculates a required angular displacement necessary to achieve said desired motion. 
   
   
       16 . The amphibious robotic device according to  claim 15 , wherein the angular control includes a yaw controller calculating a required yaw of the device, a pitch controller calculating a required pitch of the device and a roll controller calculating a required roll of the device, the desired motion including at least one of the required yaw, the required pitch and the required roll. 
   
   
       17 . A control system for autonomously maneuvering a robotic device in at least one of a liquid medium and a solid medium, the robotic device including a propulsion system having a series of individually controlled legs, the control system comprising:
 at least one visual sensor retrieving an image of an environment of the device in the medium;   an image analyzing module receiving the image, determining a presence of an object of a given type therein and analyzing at least one property of the object;   a motion calculator determining a desired motion of the device based on the at least one property of the object; and   a controller operating the propulsion system of the device, the controller calculating a respective required leg motion of each of the legs to obtain the desired motion of the device and operating each of the legs based on the respective required leg motion calculated, such that the robotic device autonomously maneuvers in said medium.   
   
   
       18 . The control system according to  claim 17 , wherein the desired motion of the device includes station keeping. 
   
   
       19 . The control system according to  claim 17 , wherein the motion calculator is programmed upon reception of the at least one property to memorize a series of at least two consecutive steps, each step including one of movement in at least one of six degrees of freedom and station keeping, the desired motion successively corresponding to each of the consecutive steps. 
   
   
       20 . The control system according to  claim 17 , wherein the image analyzing module determines an identity of the object from a given list of possible objects of the given type, the motion calculator determining the desired motion of the device from the list where a different desired motion is associated with each of at least some of the possible objects of the given type. 
   
   
       21 . The control system according to  claim 17 , wherein the image analyzing module determines a position of the object on the image and compares the position to a desired position, and the motion calculator determining the desired motion of the device such as to change the position to correspond to the desired position. 
   
   
       22 . The control system according to  claim 21 , wherein the object is moving, and the desired motion of the device allows the device to follow the object. 
   
   
       23 . The control system according to  claim 17 , wherein the motion calculator includes at least one angular controller which calculates a required angular displacement necessary to achieve said desired motion. 
   
   
       24 . The control system according to  claim 23 , wherein the angular control includes a yaw controller calculating a required yaw of the device, a pitch controller calculating a required pitch of the device and a roll controller calculating a required roll of the device, the desired motion including at least one of the required yaw, the required pitch and the required roll. 
   
   
       25 . The control system according to  claim 24 , wherein the yaw, pitch and roll controllers are PID controllers.