Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D57/00—Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track
  • B62D57/02—Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track with ground-engaging propulsion means, e.g. walking members
  • B62D57/032—Vehicles characterised by having other propulsion or other ground- engaging means than wheels or endless track, alone or in addition to wheels or endless track with ground-engaging propulsion means, e.g. walking members with alternately or sequentially lifted supporting base and legs; with alternately or sequentially lifted feet or skid
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J15/00—Gripping heads and other end effectors
  • B25J15/0009—Gripping heads and other end effectors comprising multi-articulated fingers, e.g. resembling a human hand
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J15/00—Gripping heads and other end effectors
  • B25J15/08—Gripping heads and other end effectors having finger members

Definitions

• This description relates to a mobile robot having legs for both locomotion and grasping functions.
• FIG. 3 illustrates an example of an articulated robot.
• FIG. 7 is a graph showing an example full climb analysis depicting the climbable workspace versus coxa angle and height (body height and object height).
• a four DOF legged robot can both walk over and grasp objects.
• the legs e.g., reduced actuated Klann legs
• the extra DOF provided by the coxa joint can more than triple the climbable obstacle height and enables grasping of a range of rectangular object widths.
• the robot further can be adapted and customized for environments and grasping various object shapes.
• a robot described herein can implement other numbers of DOFs, including six DOFs.
• Such a six DOF legged robot can include four drive DOFs to generate a periodic walking gait and two lift DOFs to pull legs inward to grasp objects (e.g., tubes, UXOs, extrusion, plates).
• the six DOF robot can be configured to: walk forward/ backward, point turn right /left, arc right/left, body close/open, right body close / open, left body close I open, and digging.
• an articulated crab robot can be configured to have three DoFs on each leg and modified dactyls to grasp objects. Such robot can generate a forward-moving gait and a sideways gait to efficiently search for the UXO in both directions.
• FIG. 1 illustrates a conceptual diagram showing the operational concept of an example tethered robot 10.
• the tethered robot 10 is configured to perform a method that includes: (1) using legs 11 for walking to an object 12, (2) climbing the object 12 (3) grasping the object 12, and (4) being lifted (or pulled) by a tether 14 while grasping the object 12.
• the robot 10 takes advantage of the walking ability of legs 11 for controlled walking over potentially uneven terrain.
• the robot 10 finds a target object to grasp (e.g., via direct vision by a user, an imaging device, such as a camera, and/or by other sensors).
• the robot 10 is controlled to place legs 11 on top of an object (referred to herein as a “half climb” shown at 2).
• the robot 10 is then controlled to climb on top of it until front and back legs 11 are placed on the opposite sides of the object (“full climb”) so that legs 11 can be pressed against obstacle sides with a secure grasp (shown at 3).
• the load-bearing tether 14 can provide a main lift force to retrieve the target object.
• the tether 14 can suspend the robot 10 from structure 16, such as a crane, a boat, a rotorcraft or a larger robot, to retrieve the object 12 (e.g., samples, essential tools, hazardous materials or other target objects). Because the robot 10 disclosed herein uses the same legs 11 for both locomotion (e.g., walking) and grasping, the object retrieval function can be facilitated.
• the robot 10 can be self-powered having an internal power supply (e.g., battery) and/or power can be supplied through an electrically conductive cable that forms part of the tether 14.
• an internal power supply e.g., battery
• power can be supplied through an electrically conductive cable that forms part of the tether 14.
• Many search and rescue teams prefer tethered robots because the robot 10 can always be retracted. In examples where the robot 10 is small enough to explore confined spaces and can be dragged back with larger object in tow could be especially helpful for clearing blocked infrastructure or search and rescue.
• the robot 10 can be implemented as a self-positioning end effector for a crane hook would save humans the role of securing loads in difficult to access spots.
• the robot 10 disclosed herein can be used as marine robots to walk along the sea floor and retrieve environmental samples, hazards such as unexploded munitions, or rare metal nodules have the potential to be both profitable and environmentally friendly.
• flying robots have to precisely align a hook or connector to a load, which requires a combination of skill and appropriate weather conditions.
• a walking and grasping robot, such as described herein, would reduce required precision and enable access to objects that are occluded from the sky by overhanging structures or plants.
• Example embodiments of the robot 10 described herein are different from many other types of legged robots, which can grasp objects in its environment by an attached robotic gripper, in that the whole robot 10 (including its body and legs) can be adapted to grasp the object. That is, rather than reserve some legs for locomotion, the robot 10 uses more legs 11 to contribute to the secure form or force closure of the grip. Unlike in climbing robots, which often require specialized end-effectors, the same legs 11 of the robot 10 will be used like the fingers of a grasper.
• the legs 11 can have tapered distal end portions, which can be key for secure walking in sand, rocks and other similar terrain.
• the robot can include Klann mechanism legs that have been added to the end of a coxa joint to provide an additional DOF.
• the linkage design separates the functions of the DOF when the Klann mechanisms are driven the robot moves forward (drive DOF) whereas when the coxa is driven the legs pull inward or outward like a claw (lift DOF), such as shown in the example leg mechanism of FIGS. 2A and 2B.
• the robot described herein is designed to have compatible degrees of freedom (DOF) for both drive and lift.
• the drive DOF is responsible for creating a periodic gait trajectory, using continuous rotation as input for efficiency and simplicity.
• the lift DOF is responsible for raising the legs to climb onto the obstacle and for pulling the legs inward to grasp the obstacle once it has been climbed.
• the robot includes two lift DOFs (left and right).
• the robot is also configured to steer into position, and thus includes two drive DOFs.
• the robot having four legs thus can be implemented having a total of four DOFs. Other numbers of DOFs can be implemented with robots having different numbers and configurations of legs based on the approaches described herein.
• FIG. 2A depicts an example of a dual leg mechanism 50 that can implement both locomotion and grasping functions.
• the leg mechanism 50 provides a useful example of a leg mechanism that can be used to implement each of the legs of the robots described herein (e.g., legs 11 of the robot 10; legs 102, 104, 106, 108 in the example robot 100 shown in FIG. 3).
• legs 11 of the robot 10 e.g., legs 11 of the robot 10; legs 102, 104, 106, 108 in the example robot 100 shown in FIG. 3
• the geometry and kinematics of each leg mechanism 50 can be modified from that shown and described according to intended use.
• the lengths of respective links and/or joint locations can vary depending on objects/surfaces to be grasped and environmental conditions and surface where the robot will be used.
• the leg mechanism 50 includes a dual Klann leg, which can improve the static stability and smoothness with reduced DOF.
• the leg mechanism 50 includes dual Klan linkages (also referred herein to as legs) 52 and 54 coupled to a coxa plate 56.
• the coxa plate 56 can be coupled to the chassis (or body portion) 58 of the robot by an articulated coxa joint 60 having an axis orthogonal to the coxa plate.
• the coxa joint 60 can be articulated relative to the body portion, schematically shown at 58, of the robot over an angle (a) based on actuation of a coxa actuator (see, e.g., actuator 150 of FIG. 3).
• the legs 52 and 54 are fixed to the coxa plate 56, rotation of the coxa plate also causes corresponding movement of legs 52 and 54 about the coxa joint.
• the legs 52 and 54 can be moved upward or downward, such that distal ends 62 and 64 of the legs move outwardly or inwardly (e.g., like a claw) relative to the body portion 58.
• Each of the legs 52 and 54 can have the same dimensions and configuration.
• the leg 52 includes an arrangement of links shown as n to n.
• the links can be formed of a rigid material, such as a metal or plastic.
• Each of the links can be the same material or different materials (and/or coatings) can be used in some examples.
• Link n is coupled to the coxa plate 56 by rotational joint Oi.
• Link n is coupled to the coxa plate 56 by rotational joint CL- Link is coupled to the coxa plate 56 by rotational joint
• the position of the rotational joints Oi, Ch. O3 is fixed with respect to the coxa plate 56.
• Additional rotational joints 66, 68, 70 and 72 are coupled between pairs of respective links, such as shown, to provide a cyclic trajectory for the leg 52.
• the rotational joints 66, 68, 70 and 72 are not fixed (grounded) to the coxa plate (as are joints Oi, O2, O3), and thus will move relative to the coxa plate and body portion 58 during actuation of the leg 52.
• the leg 54 can include the same links n to n and rotational joints as the leg 52 but is coupled to the articulated joint Oi at an angular offset (e.g., a fixed offset) relative to how the leg 52 is coupled to joint Oi, such as 180 degrees.
• the rotational joint (?i is an articulated joint, which is driven by a drive actuator (e.g., drive actuator 120, 122, 124, 126 shown in FIG. 3).
• the drive actuator rotates a shaft, to which the crank arm n is coupled, about the drive motor axis extending through Oi (e.g., orthogonal to the plane of the drawing sheet for FIG. 2A) resulting in a cyclic leg trajectory that will include both stance and swing.
• the drive actuator can rotate the continuously at a constant speed.
• each leg pair 52, 54 is driven together by respective crank arms n at a 180 degree offset to form the dual Klann legs.
• the example gait shown at 76 is a “locked gait” where the coxa angle a is fixed at 0°. In other examples, the gait can be fixed at different coxa angles or the coxa angle can be variable during the gate.
• the coxa actuator e.g., actuator 150 of FIG. 3
• the coxa actuator can be configured and controlled to adjust the coxa angle over a range of angles, such as ranging from -90 to +90 degrees relative to a zero coxa angle (e.g., a 180 degree range).
• a design goal of its generated single gait can be to walk smoothly and swing across small obstacles like pebbles in the uneven terrains.
• the Klann linkage mechanism can be configured to optimize the gait shape for efficient walking on a given surface.
• FIG. 2A An example definition of the gait shape is shown at 80 in FIG. 2A.
• Pi and P 2 represent the liftoff point and the touchdown point having a phase difference it, which divide the swing phase and the stance phase.
• the gait parameters Pi and P 2 can be configured to satisfy the following criteria: (a) Stride length P1P2 should be as horizontal as possible so that both stance phases of front and back legs would be co-linear; (b) Stride length P1P2 should be large enough to achieve fast speed; (c) Swing height P3P5 should be as long as possible to swing across obstacles; and (d) Stance variation P4P6 should be relatively small to reduce moving vibration.
• the objective function is shown as Eq.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Robotics (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Manipulator (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=96014175

Family Applications (1)

Country Status (1)

• 2023
  • 2023-09-05 EP EP23861387.1A patent/EP4580932A1/de active Pending

Similar Documents

Legal Events