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Matthew K Mahlin

Publications and source records attributed to Matthew K Mahlin.

Tall Lunar Tower Ground Demonstration

Time lapse of the Tall Lunar Tower (TLT) Ground EDU Demonstration performed at the Langley Research Center. The demonstration focused on using commercial off-the-shelf robotic manipulator arms with specialized end-effectors to place and join components in a jigging and lifting frame. The frame allows the assembly of a tower by the 6 degree-of-freedom manipulator arms in a work cell configuration by lifting the completed tower segments upward to allow new tower segments to be appended to the bottom of the structure. The demonstration took place from September 28th to 30th 2023.

Tall Lunar Tower↗

Sizing and Design Tool for Tall Lunar Tower

Tall lunar towers enable direct collection of solar energy using solar panels that can generate power exceeding 50kW. Tall lunar towers also support solar reflectors and concentrators for solar farms, which enable various mission architectures on the lunar surface. The Tall Lunar Tower project at NASA Langley Research Center is focused on the design, modeling, fabrication, and testing of an assembled tall lunar tower engineering development unit. This paper presents the development of a sizing and design tool for the tall lunar tower. The predicted frequency and buckling responses of the tall lunar tower from the tool are compared with the results obtained from finite element analysis.

Solar Tower↗

Sizing and Design Tool for Tall Lunar Tower

Tall lunar towers enable direct collection of solar energy using solar panels that can generate power exceeding 50kW. Tall lunar towers also support solar reflectors and concentrators for solar farms, which enable various mission architectures on the lunar surface. The Tall Lunar Tower project at NASA Langley Research Center is focused on the design, modeling, fabrication, and testing of an assembled tall lunar tower engineering development unit. This paper presents the development of a sizing and design tool for the tall lunar tower. The predicted frequency and buckling responses of the tall lunar tower from the tool are compared with the results obtained from finite element analysis.

Solar Tower↗

Cable Decoupling and Cable-Based Stiffening of Continuum Robots

Cable-driven continuum robots, which are robots with a continuously flexible backbone and no identifiable joints that are actuated by cables, have shown great potential for many applications in unstructured, uncertain environments. However, the standard design for a cable-driven continuum robot segment, which bends a continuous backbone along a circular arc, has many compliant modes of deformation which are uncontrolled, and which may result in buckling or other undesirable behaviors if not ameliorated. In this paper, we detail an approach for using additional cables to selectively stiffen planar cable-driven robots with-out substantial coupling to the actuating cables. A mechanics-based model based on the planar Cosserat equations is used to find the design conditions under which additional cables can be routed without coupling of the cable lengths for small deformations. Simulations show that even for relatively large deformations, coupling remains small. A prototype is evaluated, and it is demonstrated that the compliance of the robot is substantially modified relative to the same robot without stiffening cables. Additional stiffening cables are shown to increase the end-effector output stiffness by a factor of approximately 10 over a typical design with actuating cables.

Tendon/wire mechanism↗

Assemblers: A Modular, Reconfigurable Manipulator for Autonomous in-Space Assembly

This paper presents a modular, reconfigurable robotic manipulator for autonomous in-space assembly. On-orbit and planetary surface assembly is a challenging domain that encompasses various technological thrusts to support human exploration, science, and technology demonstration missions. The system architecture presented here addresses the need for robotic assembly of structures in locations that prohibit constant human oversight and/or teleoperation. This system is capable of scheduling, reconfiguring itself, and executing structural assembly tasks with the ability to assess construction and correct errors during the assembly as needed. An example concept of operations is presented. Details of the mechanical and electrical design of the robotic modules as well as the dynamic modeling approach, control algorithms, and sensing and perception systems are also provided.

robotics↗

Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN) Hinge Joint Structural Performance

The Tendon Actuated Lightweight In-Space MANipulator (TALISMAN), invented and initially developed under the Space Technology Mission Directorate Human Robotics Systems program, is a tendon-actuated robot that established a new structural architecture for long-reach space manipulators. The TALISMAN is designed to have significant stiffness and strength in the plane of the tendons or cables, and operations are designed such that all primary loads are applied in that same plane. However, during normal operations it is possible for out-of-plane forces to be applied on the TALISMAN when secondary loads are imparted by a tool or action at the wrist. These secondary loading conditions will induce out-of-plane bending loads in the TALISMAN hinge joints. The TALISMAN hinge joints must be designed for these out-of-plane loads, to ensure no failure of the joint occurs during operations. A series hinge joint out-of-plane stiffness tests were conducted at five different joint angles; at three cable pre-loads from 25-lbf to 100-lbf; up to an equivalent out-of-plane tip load of 27.28-lbf at the end of a 51-in. long distal link. The objective of the tests was to provide an initial set of deflection, cable load, and strain data to inform accurate modeling of the hinge joint out-of-plane stiffness. The test objective was achieved by developing an FEM of the hinge joint able to predict tip displacement to within 10% of values measured in tests. The hinge joint FEM may now be implemented into a full-scale analysis model of the TALISMAN V2.0 to provide predictions of out-of-plane displacement under different load and joint angle conditions.

Matthew K Mahlin↗

Near-term Persistent Platform Orbital Testbed: Three Candidate Architecture Options

On-orbit Servicing, Assembly, and Manufacturing (OSAM) will revolutionize the space industry by transforming the concept of operations of space systems and enabling new, radically different system implementations. These new implementations will benefit from a novel persistent asset design paradigm which focuses on evolvable designs that are tailored to the operational environment, not the launch environment. In addition, the ability to launch sub-systems independently enable future persistent assets to economically expand in capability and size, achieving cost effective and productive operations lasting for decades like terrestrial observatories. With few exceptions (International Space Station, Hubble Space Telescope, Mission Extension Vehicle customers), current space systems are not visited once they are operational. Leveraging emerging low cost commercial launch provides the ability to repeatedly and routinely revisit space systems. Thus, revolutionary new approaches for space system design are possible, creating completely new opportunities for small businesses and accelerating the growth of already established space industries. To usher in the revolutionary new operational paradigm, two things are needed. First, to build confidence in the technology and new paradigm, there must be a leading example, a bellwether persistent asset, that demonstrates the reliability and maturity of the new persistent asset paradigm (where repeated visits are common). Second, in order to rapidly advance and validate OSAM capabilities, an efficient means is required to conduct tests in the space environment. A persistent platform testbed satisfies both these needs. The space environment exhibits a plethora of characteristics that are difficult and costly to accurately simulate for a full system in a terrestrial laboratory, such as near zero gravity, a wide range of ionizing radiation types, atomic oxygen, and micro-meteoroids and space debris traveling at high velocity. In addition, since persistent assets range in mass from a few grams to several metric tons, it is difficult to accurately simulate interactions between these systems and visiting vehicles (that also exhibit a wide range of varying masses and capabilities). These interactions include the transmission of forces and/or exchanging mass (in the form of instruments, fuel, robotic assets, etc.). Thus, a rapid, versatile and cost efficient in-space testing capability that includes a persistent test platform and a surrounding in-space test zone is needed to mature technologies through experimentation. The testbed can provide common services, such as: power, thermal control, vibration isolation, data transmission between experiments and terrestrial experimenters, station-keeping, pointing, and robotic agents that can be leveraged by customer experiments. The onboard robotic agents can be used to provide payload handling services, such as: assembly, change out or upgrade, relocation, connecting/disconnecting utilities, inspection, repair or servicing, etc. Since the persistent platform cost will be amortized over many hosted payloads, its services can eventually be offered at a price much lower than if one were to design a unique and dedicated spacecraft and mission for those few experiments. The key to achieving an effective testbed is providing efficient cost effective access and infrastructure to a variety of commercial, academic and government customers coupled with extensibility, in the capability of an individual persistent platform test bed or replication of the test bed in a different operational regime. Three potential options for implementing a test bed were developed and evaluated in this study.

Persistent Platform↗

Software Design for the Supervised Autonomous Assembly of a Tall Lunar Tower

Tall towers enable a wide-ranging set of capabilities on the lunar surface including communication, navigation, surveillance, power generation, and more. The Tall Lunar Tower project at NASA Langley Research Center is focused on the design, modeling, fabrication, and testing of an engineering development unit to assemble a tall tower through supervised autonomous operations. In this paper, the software design for the supervised autonomous assembly of a tall lunar tower is presented. The paper includes a high-level description of the concept of operations, the agents, and an overview of the software architecture.

Moon↗

Sizing, Buckling, and Thermal-Structural Analysis of Tall Lunar Tower

Tall lunar towers enable direct collection of solar energy using solar panels that can generate power exceeding 100-kW above shadowed regions on the surface. Tall lunar towers also support solar reflectors and concentrators for solar farms, which enable various mission architectures on the lunar surface. The Tall Lunar Tower (TLT) project at NASA Langley Research Center is focused on the design, modeling, fabrication, and testing of an assembled TLT Engineering Development Unit (EDU). In this paper, the design and analysis plan of a TLT is presented and predicted buckling and thermal-structural response of the TLT EDU on the lunar surface are investigated.

Kyongchan Song↗

Scaling Climbing Collaborative Mobile Manipulators (C2M2) for Outfitting a Tall Lunar Tower (TLT) and Truss Structures

In-space and planetary truss structures like the Tall Lunar Tower (TLT) can greatly benefit from truss climbing collaborative mobile manipulators (C-CMMs) for outfitting and other servicing tasks. Mobile robotic systems traversing these structures will allow for improved access to the structure for placing equipment and routing cables after the structure has been assembled. The robotic system described in the proposed paper is designed to provide access to the structure through collaborative mobile robotics. The paper will provide a method to constrain the design of such a robot via the geometry of the truss structure and the controlling joint torques across various gaits. The focus of the design is on a six-degree of freedom (DOF) robot arranged with two-DOF at each end and at the center. The variable features of this system are the actuators and the length of the links connecting the two-DOF modules. The result of the analysis is a link sizing range which the robot can be designed within to ensure functionality on the truss structure. A C-CMM will be designed using the scaling utility and several constructed to demonstrate operating both independently and collaboratively.

in-space assembly↗

Hardware Systems and EDU Demonstration of the Tall Lunar Tower Project

The Tall Lunar Tower (TLT) project developed a robotic tower assembly system (RTAS) and TLT Truss engineering development units (EDUs) to perform a ground demonstration of supervised semi-autonomous robotic assembly of a truss-based tall tower. Truss structures provide exceptional strength-to-weight ratios for payload capabilities supporting large masses. On the lunar surface, tall towers are a critical structural system that will enable significant solar power generation by supporting vertical solar arrays and beyond-the-horizon communications at the lunar south pole, supporting the Artemis mission architecture, as well as a lunar economy. Tall towers, greater than 30-meters-tall, provide the elevation needed for more consistent solar power generation due to low inclination sunlight and deep shadowing from surface features on the lunar surface at the poles. The robotic structural assembly technologies developed for truss-based tall towers will also enable other large-scale functional lunar structures to be built, including launch plume deflectors, lunar safe havens for astronauts and assets, surface transportation for cargo, and other critical infrastructure. Robotic assembly of truss structures for lunar surface infrastructure is near-term enabling for future Artemis mission campaign and Moon to Mars Objectives needs for power and communication. The project team designed, fabricated, tested, and demonstrated the RTAS EDU by assembling a TLT Truss EDU in a laboratory environment. The hardware systems and the supervised semi-autonomous assembly process for a TLT assembled EDU design, along with descriptions of a hardware demonstration are presented.

In-space Assembly↗