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At least 127 records · Page 7

Goal driven kinematic simulation of flexible arm robot for space station missions

Flexible arms offer a great degree of flexibility in maneuvering in the space environment. The problem of transporting an astronaut for extra-vehicular activity using a space station based flexible arm robot was studied. Inverse kinematic solutions of the multilink structure were developed. The technique is goal driven and can support decision making for configuration selection as required for stability and obstacle avoidance. Details of this technique and results are given.

Janssen, P.↗

Obstacle avoidance for redundant robots using configuration control

The article presents a new and simple solution to the obstacle avoidance problem for redundant robots. In the proposed approach, called configuraiton control, the redundancy is utilized to configure the robot so as to satisfy a set of kinematic inequality constraints representing obstacle avoidance, while the end-effector is tracking a desired trajectory. The robot control scheme is very simple, and uses on-line adaptation to eliminate the need for the complex dynamic model and parameter values of the robot. Several simulation results for a four-link planar robot are presented to illustrate the versatility of the approach. These include reaching around a stationary obstacle, simultaneous avoidance of two obstacles, robot reconfiguration to avoid a moving obstacle, and avoidance of rectangular obstacles.

Colbaugh, R.↗

Design of a simulation environment for laboratory management by robot organizations

This paper describes the basic concepts needed for a simulation environment capable of supporting the design of robot organizations for managing chemical, or similar, laboratories on the planned U.S. Space Station. The environment should facilitate a thorough study of the problems to be encountered in assigning the responsibility of managing a non-life-critical, but mission valuable, process to an organized group of robots. In the first phase of the work, we seek to employ the simulation environment to develop robot cognitive systems and strategies for effective multi-robot management of chemical experiments. Later phases will explore human-robot interaction and development of robot autonomy.

Zeigler, Bernard P.↗

Performance of the Satellite Test Assistant Robot in JPL's Space Simulation Facility

An innovative new telerobotic inspection system called STAR (the Satellite Test Assistant Robot) has been developed to assist engineers as they test new spacecraft designs in simulated space environments. STAR operates inside the ultra-cold, high-vacuum, test chambers and provides engineers seated at a remote Operator Control Station (OCS) with high resolution video and infrared (IR) images of the flight articles under test. STAR was successfully proof tested in JPL's 25-ft (7.6-m) Space Simulation Chamber where temperatures ranged from +85 C to -190 C and vacuum levels reached 5.1 x 10(exp -6) torr. STAR's IR Camera was used to thermally map the entire interior of the chamber for the first time. STAR also made several unexpected and important discoveries about the thermal processes occurring within the chamber. Using a calibrated test fixture arrayed with ten sample spacecraft materials, the IR camera was shown to produce highly accurate surface temperature data. This paper outlines STAR's design and reports on significant results from the thermal vacuum chamber test.

Mcaffee, Douglas↗

Kinematics and control algorithm development and simulation for a redundant two-arm robotic manipulator system

An efficient approach to cartesian motion and force control of a 7 degree of freedom (DOF) manipulator is presented. It is based on extending the active stiffness controller to the 7 DOF case in general and use of an efficient version of the gradient projection technique for solving the inverse kinematics problem. Cooperative control is achieved through appropriate configuration of individual manipulator controllers. In addition, other aspects of trajectory generation using standard techniques are integrated into the controller. The method is then applied to a specific manipulator of interest (Robotics Research T-710). Simulation of the kinematics, dynamics, and control are provided in the context of several scenarios: one pertaining to a noncontact pick and place operation; one relating to contour following where contact is made between the manipulator and environment; and one pertaining to cooperative control.

Hennessey, Michael P.↗

Microgravity flight testing of a laboratory robot

A review is given of the conditions and preparations for studying the performance of a robotic laboratory manipulator under microgravity conditions and by means of dynamic simulations. The robotic arm is fitted with accelerometers, incorporated into a materials-transfer workcell, and flown on a microgravity simulator. A software package based on the Lagrangian form of the equations of motion is used for dynamic analysis and control-systems development of the arm.

Hinman, Elaine M.↗

Mission Simulation Facility: Simulation Support for Autonomy Development

The Mission Simulation Facility (MSF) supports research in autonomy technology for planetary exploration vehicles. Using HLA (High Level Architecture) across distributed computers, the MSF connects users autonomy algorithms with provided or third-party simulations of robotic vehicles and planetary surface environments, including onboard components and scientific instruments. Simulation fidelity is variable to meet changing needs as autonomy technology advances in Technical Readiness Level (TRL). A virtual robot operating in a virtual environment offers numerous advantages over actual hardware, including availability, simplicity, and risk mitigation. The MSF is in use by researchers at NASA Ames Research Center (ARC) and has demonstrated basic functionality. Continuing work will support the needs of a broader user base.

Pisanich, Greg↗

Simulation study of the ROMPS robot control system

This is a report presenting the progress of a research grant funded by NASA for work performed from June 1, 1993 to August 1, 1993. The report deals with the Robot Operated Material Processing System (ROMPS). It presents results of a computer simulation study conducted to investigate the performance of the control systems controlling the azimuth, elevation, and radial axes of the ROMPS and its gripper. Four study cases are conducted. The first case investigates the control of free motion of the three areas. In the second case, the compliant motion in the elevation axis with the wrist compliant device is studied in terms of position accuracy and impact forces. The third case focuses on the behavior of the control system in controlling the robot motion along the radial axis when pulling the pallet out of the rack. In the fourth case, the compliant motion of the gripper grasping a solid object under the effect of the gripper passive compliance is studied in terms of position accuracy and contact forces. For each of the above cases, a set of PIR gains will be selected to optimize the controller performance and computer simulation results will be presented and discussed.

Nguyen, Charles C.↗

Method for neural network control of motion using real-time environmental feedback

A method of motion control for robotics and other automatically controlled machinery using a neural network controller with real-time environmental feedback. The method is illustrated with a two-finger robotic hand having proximity sensors and force sensors that provide environmental feedback signals. The neural network controller is taught to control the robotic hand through training sets using back- propagation methods. The training sets are created by recording the control signals and the feedback signal as the robotic hand or a simulation of the robotic hand is moved through a representative grasping motion. The data recorded is divided into discrete increments of time and the feedback data is shifted out of phase with the control signal data so that the feedback signal data lag one time increment behind the control signal data. The modified data is presented to the neural network controller as a training set. The time lag introduced into the data allows the neural network controller to account for the temporal component of the robotic motion. Thus trained, the neural network controlled robotic hand is able to grasp a wide variety of different objects by generalizing from the training sets.

Buckley, Theresa M.↗

Adjustable Autonomy Testbed

The Adjustable Autonomy Testbed (AAT) is a simulation-based testbed located in the Intelligent Systems Laboratory in the Automation, Robotics and Simulation Division at NASA Johnson Space Center. The purpose of the testbed is to support evaluation and validation of prototypes of adjustable autonomous agent software for control and fault management for complex systems. The AA T project has developed prototype adjustable autonomous agent software and human interfaces for cooperative fault management. This software builds on current autonomous agent technology by altering the architecture, components and interfaces for effective teamwork between autonomous systems and human experts. Autonomous agents include a planner, flexible executive, low level control and deductive model-based fault isolation. Adjustable autonomy is intended to increase the flexibility and effectiveness of fault management with an autonomous system. The test domain for this work is control of advanced life support systems for habitats for planetary exploration. The CONFIG hybrid discrete event simulation environment provides flexible and dynamically reconfigurable models of the behavior of components and fluids in the life support systems. Both discrete event and continuous (discrete time) simulation are supported, and flows and pressures are computed globally. This provides fast dynamic simulations of interacting hardware systems in closed loops that can be reconfigured during operations scenarios, producing complex cascading effects of operations and failures. Current object-oriented model libraries support modeling of fluid systems, and models have been developed of physico-chemical and biological subsystems for processing advanced life support gases. In FY01, water recovery system models will be developed.

Malin, Jane T.↗

Development of the Advanced Regolith Ground Operations (ARGO) Test Bed– A Robotic Construction Test Facility with Simulated Lunar Environments

NASA’s Artemis Program is working towards developing a sustained presence on the Moon and eventually Mars. To achieve this goal, robotic excavation, site preparation and construction technologies are under development to establish the capability to construct infrastructure such as launch/landing pads and radiation protection shelters. Technologies must be proven in simulated Lunar conditions prior surface demonstration missions. To that end, the Relevant Additive Construction Technology (REACT) Announcement of Collaboration Opportunities (ACO) project with AI Space Factory and the NASA Kennedy Space Center’s (KSC) Granular Mechanics and Regolith Operations Laboratory (a.k.a. Swamp Works) has developed the Advanced Regolith Ground Operations (ARGO) Test Bed. ARGO includes a ~1.5m x 1.5m x 1.2m (~5x5x4ft) vacuum chamber, cryogenically cooled thermal shroud, a 3-axis robotic positioning system, and a regolith bin. For the REACT project, a pellet extruder and feed hopper have been installed on ARGO to advance the Technology Readiness Level (TRL) of regolith-polymer composite Fused Deposition Modeling (FDM) additive construction systems, processes, and materials. This paper will focus on the design and operational characteristics of the ARGO Test Bed with pellet extruder.

Moon↗

The dynamic effects of internal robots on Space Station Freedom

Many of the planned experiments of the Space Station Freedom (SSF) will require acceleration levels to be no greater than microgravity (10 exp -6 g) levels for long periods of time. Studies have demonstrated that without adequate control, routine operations may cause disturbances which are large enough to affect on-board experiments. One way to both minimize disturbances and make the SSF more autonomous is to utilize robots instead of astronauts for some operations. The present study addresses the feasibility of using robots for microgravity manipulation. Two methods for minimizing the dynamic disturbances resulting from the robot motions are evaluated. The first method is to use a robot with kinematic redundancy (redundant links). The second method involves the use of a vibration isolation device between the robot and the SSF laboratory module. The results from these methods are presented along with simulations of robots without disturbance control.

Miller, Jeffrey H.↗

The dynamic effects of internal robots on Space Station Freedom

Many of the planned experiments of the Space Station Freedom (SSF) will require acceleration levels to be no greater than microgravity (10 exp -6 g) levels for long periods of time. Studies have demonstrated that without adequate control, routine operations may cause disturbances which are large enough to affect on-board experiments. One way to both minimize disturbances and make the SSF more autonomous is to utilize robots instead of astronauts for some operations. The present study addresses the feasibility of using robots for microgravity manipulation. Two methods for minimizing the dynamic disturbances resulting from the robot motions are evaluated. The first method is to use a robot with kinematic redundancy (redundant links). The second method involves the use of a vibration isolation device between the robot and the SSF laboratory module. The results from these methods are presented along with simulations of robots without disturbance control.

Miller, Jeffrey H.↗

Using Generative Representations to Evolve Robots

Recent research has demonstrated the ability of evolutionary algorithms to automatically design both the physical structure and software controller of real physical robots. One of the challenges for these automated design systems is to improve their ability to scale to the high complexities found in real-world problems. Here we claim that for automated design systems to scale in complexity they must use a representation which allows for the hierarchical creation and reuse of modules, which we call a generative representation. Not only is the ability to reuse modules necessary for functional scalability, but it is also valuable for improving efficiency in testing and construction. We then describe an evolutionary design system with a generative representation capable of hierarchical modularity and demonstrate it for the design of locomoting robots in simulation. Finally, results from our experiments show that evolution with our generative representation produces better robots than those evolved with a non-generative representation.

Hornby, Gregory S.↗

Design of Rigid-Flex PCB Robotics Leveraging Validated Finite Element Simulations

The use of rigid-flex printed circuit board (PCB) as primary structure has the potential to reduce the weight and volume of robotic systems. In the case of robotics for interplanetary exploration, these systems can leverage origami-inspired folding for increased mobility options and reduced storage volume. Folding rigid-flex PCB robotics can be constructed with rigid PCB connected by short Nomex fabric hinges coupled with flex PCB ribbon cables that permits enhanced system flexibility and energy dissipation to promote impact survivability. This paper presents a design methodology of rigid-flex PCB systems with an emphasis on impact resistance. The design process considers solder joint adequacy, panel bending, and fracture using a finite element (FE) model. The proposed design methodology is developed using a case study with NASA JPL's Pop-Up Folding Flat Explorer Robot (PUFFER). First, the finite-element (FE) modeling methodology is presented with consideration to both frequency and time-domain modeling applications, which include operational self-contact analysis and high impact scenarios. The time-domain impact modeling methodology utilizes hyperelastic material properties for the Nomex hinges. This modeling method is validated using image correlation of PUFFER drop tests. A flowchart is presented to guide users through a validated Abaqus modeling procedure for highly flexible rigid-flex systems. Next, a case study is presented in which PUFFER is subject to drop heights representative of falls into Lunar pits and then the design is refined for a more optimum impact performance. Finally, the results of the case study are used to inform a generalized design methodology for rigid-flex PCB robotics subject to high-impact loads with the considerations presented.

John Bell↗

Design of Rigid-Flex PCB Robotics Leveraging Validated Finite Element Simulations

The use of rigid-flex printed circuit board (PCB) as primary structure has the potential to reduce the weight and volume of robotic systems. In the case of robotics for interplanetary exploration, these systems can leverage origamiinspired folding for increased mobility options and reduced storage volume. Folding rigid-flex PCB robotics can be constructed with rigid PCB connected by short Nomex fabric hinges coupled with flex PCB ribbon cables that permits enhanced system flexibility and energy dissipation to promote impact survivability. This paper presents a design methodology of rigidflex PCB systems with an emphasis on impact resistance. The design process considers solder joint adequacy, panel bending, and fracture using a finite element (FE) model. The proposed design methodology is developed using a case study with NASA JPL’s Pop-Up Folding Flat Explorer Robot (PUFFER). First, the finite-element (FE) modeling methodology is presented with consideration to both frequency and time-domain modeling applications, which include operational self-contact analysis and high impact scenarios. The time-domain impact modeling methodology utilizes hyperelastic material properties for the Nomex hinges. This modeling method is validated using image correlation of PUFFER drop tests. A flowchart is presented to guide users through a validated Abaqus modeling procedure for highly flexible rigid-flex systems. Next, a case study is presented in which PUFFER is subject to drop heights representative of falls into Lunar pits and then the design is refined for a more optimum impact performance. Finally, the results of the case study are used to inform a generalized design methodology for rigid-flex PCB robotics subject to high-impact loads with the considerations presented.

de la Croix, Jean-Pierre↗

Making ROBONAUT an Intelligent Assistant for Humans

This presentation is an overview of the Robonaut project. Robonaut is a humanoid robot designed by the Automation, Robotics, and Simulation Division at NASA's Johnson Space Center. The Robonaut project seeks to develop and demonstrate a robotic system that can function as an EVA astronaut equivalent. Robonaut jumps generations ahead by eliminating the robotic scars (e.g., special robotic grapples and targets) and specialized robotic tools of traditional on-orbit robotics. However, it still keeps the human operator in the control loop through its telepresence control system. Robonaut is being designed for "EVA" tasks, i.e., those that were not specifically designed for robots. Our challenge is to build machines that can help humans work and explore in space. Working side by side with humans, or going where the risks are too great for people, machines like Robonaut will expand our ability for construction and discovery. Central to that effort is a capability we call dexterous manipulation, embodied by an ability to use ones hand to do work, and our challenge is to build machines with dexterity that exceeds that of a suited astronaut.

Savely, Robert T.↗

Mobile Applications and Multi-User Virtual Reality Simulations

This is my third internship with NASA and my second one at the Johnson Space Center. I work within the engineering directorate in ER7 (Software Robotics and Simulations Division) at a graphics lab called IGOAL. We are a very well-rounded lab because we have dedicated software developers and dedicated 3D artist, and when you combine the two, what you get is the ability to create many different things such as interactive simulations, 3D models, animations, and mobile applications.

Gordillo, Orlando Enrique↗