System and method for proprioceptive and responsive robotic door opening
The present disclosure pertains to a system and method for a robotic arm mounted on a mobile base, wherein the robotic arm applies a desired force at a point of contact between an arm and a point in the environment. One method involves low-level, automated coordination, wherein the higher-level decision making is made by a human operator, while another method addresses the variability of success in visual identification of door features, by increasing the reliance on proprioceptive cues such as forces from the door and door hinge and reducing reliance on exteroceptive cues.
1 . A system for proprioceptive and responsive robotic door opening, said system comprising:
a legged robot comprising a robot base, one or more legs attached to said robot base and configured to locomote across a variety of terrain and able to withstand toppling forces from door-opening interactions, and at least one robot arm, said robot arm comprising an arm base, a plurality of arm base actuators, an arm first link, an arm second link, a plurality of wrist actuators, an end-effector, and at least one camera;
a user interaction device; and
a processor coupled to a memory, said processor configured to send and receive data from said user interaction device and said legged robot, wherein upon receiving a command to execute door-opening instructions, said processor causes said legged robot to:
approach a door;
engage with a door-opening mechanism associated with said door using said end-effector to open said door while maintaining a controlled distance to said door until said door is opened;
advance at least a portion of said legged robot through a door frame of said door; and
autonomously maintain contact with said door by one of a part of said robot arm or a part of said legged robot in order to maintain an open position of said door until said legged robot has cleared through a door frame.
2 . The system of claim 1 , wherein said door-opening mechanism is a doorknob.
3 . The system of claim 1 , wherein said door-opening mechanism is a door handle.
4 . The system of claim 1 , wherein said door-opening mechanism is a push-bar.
5 . The system of claim 1 , wherein said user interaction device comprises at least one joystick.
6 . The system of claim 1 , wherein said user interaction device receives visual and audio data from said robot.
7 . The system of claim 1 , wherein said end-effector is a gripper with gripper jaws.
8 . A method for proprioceptive and responsive robotic door opening, said method comprising:
sending instructions from a user interaction device to a robot, said robot configured to locomote across a variety of terrain and able to withstand toppling forces from door-opening interactions, said robot comprising a robot base, a processor, one or more legs, and at least one robotic arm comprising an arm base, a plurality of arm base actuators, an arm first link, an arm second link, a gripper with gripper jaws, at least one camera, and a wrist comprising a plurality of wrist actuators;
positioning said gripper in a pre-grasp pose at an algorithmically calculated angle with respect to a door-opening mechanism;
aligning said robot base and said one or more legs with said door-opening mechanism;
closing said gripper on said door-opening mechanism;
confirming, using proprioceptive sensory information collected via said robot, that a grasp of said door-opening mechanism is successful;
manipulating said door-opening mechanism via controlling the velocity of said gripper along a roll axis;
setting an impedance of said wrist to minimize moments along a vertical axis;
selecting a virtual force to be applied by said arm at said gripper according to a virtual spring impedance controller in order to ensure that a position of a door contact point with respect to said robot stays at a controlled distance;
driving said robot in a direction that matches an opening direction of said door;
determining, by said processor, a kinematic constraint imposed by a door hinge from gripper position data collected over time;
planning a path for said gripper to release said door opening mechanism and navigating through a door frame associated with said door; and
maintaining a lateral position of said robot at the center of said door frame with respect to an estimated door hinge location, and autonomously maintaining contact with said door by one of a part of said robot arm or a part of said legged robot in order to maintain an open position of said door until said legged robot has cleared through a door frame.
9 . The method of claim 8 , wherein said door-opening mechanism is a doorknob.
10 . The method of claim 8 , wherein said door-opening mechanism is a door handle.
11 . The method of claim 8 , wherein said door-opening mechanism is a push-bar.
12 . The method of claim 8 , wherein said door is a push door, and said robot is navigated accordingly.
13 . The method of claim 8 , wherein said door is a pull door, and said robot is navigated accordingly.
14 . The method of claim 8 , wherein said robot is in communication with a user interaction device capable of controlling at least one aspect of robot navigation.
15 . The method of claim 8 , further comprising:
determining, by said processor, said door opens away from said robot base;
determining, by said processor, a kinematic constraint imposed by a door hinge from gripper position data; estimating a location of said door opening using said kinematic constraint;
navigating said robot base through a door frame associated with said door while at least a portion of the robot holds open said door autonomously; and
maintaining a lateral position of said robot near a center of said door frame with respect to an estimated door hinge location.
16 . The method of claim 8 , further comprising: determining, by said processor, said door opens toward said robot base determining, by said processor, a kinematic constraint imposed by a door hinge from gripper position data;
estimating a location of said door opening using said kinematic constraint;
determining, by said processor, said door is sufficiently open;
employing door-blocking to maintain sufficient opening of said door;
planning a path for said gripper to release said door-opening mechanism and regrasp said door using said arm on an opposite side of said door;
navigating said robot base through a door frame associated with said door while maintaining sufficient opening of said door; and
maintaining a lateral position of said robot near a center of said door frame with respect to an estimated door hinge location.
17 . The method of claim 16 , wherein said door-blocking comprises positioning at least a portion of said robot body in a closing path of said door.
18 . The method of claim 16 , wherein said door-blocking comprises positioning of one or more of a robot leg or robot foot in a closing path of said door.
19 . The method of claim 16 , wherein a door-blocking mechanism is not required because the door is not weighted or sprung to close automatically.
20 . A system for proprioceptive and responsive robotic door opening, said system comprising:
a legged robot comprising a robot base, one or more legs attached to said robot base and configured to locomote across a variety of terrain, in multiple directions, able to withstand toppling forces from door-opening interactions, and at least one robot arm, said robot arm comprising an arm base, a plurality of arm base actuators, an arm first link, an arm second link, a plurality of wrist actuators, a gripper, and at least one camera;
a user interaction device; and
a processor coupled to a memory, said processor configured to send and receive data from said user interaction device and said legged robot, wherein upon receiving a command to execute door-opening instructions, said processor causes said legged robot to:
position said gripper in a pre-grasp pose with respect to a door-opening mechanism, wherein said door-opening mechanism is identified by said legged robot;
align said robot base and said one or more legs with said door-opening mechanism;
close said gripper on said door-opening mechanism;
confirm, using proprioceptive sensory information collected via said robot, that a grasp of said door-opening mechanism is successful;
manipulate said door-opening mechanism via controlling the velocity of said gripper along a roll axis;
set an impedance of said wrist to minimize moments along a vertical axis; select a virtual force to be applied by said arm at said gripper according to a virtual spring impedance controller in order to ensure that a position of a door contact point with respect to said robot stays at a controlled distance; drive said robot in a direction that matches an opening direction of said door;
determine a kinematic constraint imposed by a door hinge from gripper position data collected over time;
plan a path for said gripper to release said door opening mechanism and navigate through a door frame associated with said door; and
maintain a lateral position of said robot at the center of said door frame with respect to an estimated door hinge location.
21 . The system of claim 20 , wherein said door-opening mechanism is a doorknob.
22 . The system of claim 20 , wherein said door-opening mechanism is a door handle.
23 . The system of claim 20 , wherein said door-opening mechanism is a push-bar.
24 . The system of claim 20 , wherein said user interaction device comprises at least one joystick.
25 . The system of claim 20 , wherein said user interaction device receives visual and audio data from said robot.