Tethered Mobile Climbing Robot for Inspecting Tanks in Confined Environments

Abstract

A Mobile Climbing Robot (MCR) with wheel or endless-track type propulsion using magnetic attraction for generating adhering forces is adapted to climbing non-planar surfaces such as intersecting walls, pipes or other structural members. A tether is connected to the MCR through a tether linkage that causes the tether to bend with a radius that keeps it from protruding outside of the MCR wheels. The purpose of this is to increase the mobility when passing over variations of the climbing surface such as edges or corners. The purpose is to further protect the tether from wear caused by rubbing with the climbing surface.

Claims

1) A magnetic-based climbing robot for traversing a climbing surface and can accommodate variations in geometry of the climbing surface such as edges and corners comprising, a chassis at least one propulsion wheel attached to the chassis a permanent magnet a tether linkage a tether.

2) The climbing robot of claim 1 wherein the tether linkage includes an elastic tether holder

3) The climbing robot of claim 1 wherein the tether linkage contains an emergency recovery cord that is directly attached to the chassis.

4) The climbing robot of claim 1 wherein the tether linkage contains a camera that can view along the tether.

5) A suction-based climbing robot for traversing a climbing surface and can accommodate variations in geometry of the climbing surface such as edges and corners comprising, a chassis at least one propulsion wheel attached to the chassis a suction chamber a tether linkage wherein the tether linkage creates a port that can rotate by 90 degrees or more about one axis with sliding baffles that restrict air flow to maintain pressure or vacuum in air transferred to the suction-based climbing robot. a tether that includes a tube that transmits air flow under pressure or vacuum.

6) The climbing robot of claim 5 wherein the tether linkage includes an elastic tether holder

7) The climbing robot of claim 5 wherein the tether linkage contains an emergency recovery cord that is directly attached to the chassis.

8) The climbing robot of claim 5 wherein the tether linkage contains a camera that can view along the tether.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 shows an isometric view of the basic form of the climbing vehicle with tether linkage

[0010] FIG. 2 shows a side view of the basic form of the climbing vehicle with tether linkage

[0011] FIG. 3 shows the basic form of the climbing vehicle with tether linkage navigating a convex surface

[0012] FIG. 4 shows the basic form of the climbing vehicle with tether linkage navigating a concave surface

[0013] FIG. 5 shows the climbing vehicle with tether linkage in multiple positions traveling through a constrained area

[0014] FIG. 6 shows a view of the climbing vehicle with tether linkage where the climbing vehicle uses suction to generate adhering forces to the climbing surface, and the tether linkage can transfer both electrical signals and air pressure

DETAILED DESCRIPTION OF THE INVENTION

[0015] The invention disclosed here describes a mobile climbing robot (MCR) that is able to traverse climbing surfaces while accommodating variations in the geometry of the climbing surface such as edges or corners. In a basic form, the invention consists of a chassis (1), propulsion members shown as wheels (2) in the figures but could also be tracks, magnets (3) for generating adhering forces with the climbing surface (or suction chamber, (7), FIG. 6), drive motors with gearing transmission (4), tether linkage (5), and tether (6) as shown in FIGS. 1 and 2. The climbing vehicle is operating on a climbing surface that may contain variations in geometry such as edges or corners. The chassis forms the body of the MCR and can be used to mount inspection or remediation tools or other components. The tether linkage is pivotally connected to the chassis through a revolute joint. The location of the revolute joint can be selected for preferred motion of the tether linkage. In a general sense, locating the tether linkage revolute joint with one of the axes of the propulsion members offers good performance. The tether linkage allows high mobility of a tethered mobile robot when navigating through regions of changing geometry. A tethered mobile robot is one which has a tether, cable or other connection running from some fixed location to the mobile robot and remains attached during operation. In general, the tether can create difficulties with operation of the mobile robot when operating over varying geometries. One such example is passing through vent regions as shown in FIG. 5. The purpose of the tether linkage is to maximize the size of the vehicle by adapting the mobile robot and tether attachment geometry to the climbing surface.

[0016] FIG. 3 shows the basic form of the MCR climbing over convex climbing surface with the tether linkage adapting to the changing geometry. These figures demonstrate some of the benefits of the tether linkages. The tether linkage serves multiple purposes. It keeps the causes the tether to move in a kinematically prescribed motion relative to the mobile robot chassis in the region near the mobile robot. It protects the tether at attachment due to flexure or climbing surface edges. It can allow for very large range of motion of the tether at the point of attachment, even for large tethers. One way in which this can be achieved is by incorporating slip rings or loops of tether within the tether linkage. The tether linkage can also serve as a junction box in connecting electronic components of the robot to the tether. The tether linkage can serve as a location for providing strain-relief in the attachment of the tether to critical components within the robot. The tether linkage can serve as a location to attach a strong cord to be used for retrieving the robot.

[0017] In situations where the mobile robot is a climbing mobile robot and relatively small, it is important to reduce external forces on the robot to maximize that effect of adhering forces between the robot and the climbing surface (these adhering forces could come from magnetics or suction for example). A tether or cable commonly has inherent bending stiffness. When the climbing robot is navigating over a changing surface, the bending moment of a traditional, fixed tether or cable could generate a moment on the climbing robot which could reduce its ability to climb. The tether linkage is created from a kinematic pair, revolute joint which can create no moment about the axis of rotation and reduce any moments at the connection between the tether and the robot within the tether linkage.

[0018] Finally, the tether linkage forms an additional rigid body directed along the axis of the tether. This can serve as a location to place a camera and view along the tether. This can be useful in navigating in and through passageways with changing geometry.

[0019] FIG. 4 shows the basic form of the MCR climbing over a concave climbing surface with the tether linkage adapting to the changing geometry.

[0020] FIG. 6 shows how the tether linkage could also be adapted to create a port for transferring air under pressure or vacuum to the MCR chassis.

[0021] The tether connecting to the tether linkage can formed of multiple members, such as power cable, control signal cable and feedback signal cables, as well as emergency recovery cord and over covering.

[0022] The invention can apply to mobile robots in climbing or ground-based applications.