23 accepted papers
We report a novel stable Model-Based Adaptive Velocity Tracking Controller (AVTC) for ground vehicles capable of asymptotically exactly tracking longitudinal and yaw reference velocities and simultaneously adaptively identifying unknown plant parameters and actuator parameters. The reported AVTC is
This paper reports a numerical method for modeling underwater vehicle (UV) interactions with the free surface using a finite-dimensional dynamical plant model. Although finite-dimensional plant models of fully submerged UV behavior are well-established, they are unable to model the ubiquitous condit…
We report a novel model-based nullspace adaptive trajectory-tracking control (NS-ATTC) algorithm for fully-actuated 6-degree-of-freedom (DOF) underwater vehicles which estimates unknown plant and actuator model parameters simultaneously. We provide a stability and convergence analysis with proof of…
Teleoperation of robots in space is challenging due to high latency and limited workspace visibility. Previously, the Interactive Planning and Supervised Execution (IPSE) and Augmented Virtuality systems were developed to reduce failure risk. These tools were visualized on a 3D da Vinci surgical con…
We report the development of novel fault detection and isolation (FDI) methods for model-based fault detection (MB-FD) and quotient-space fault isolation (QS-FI). This FDI approach performs MB-FD and QS-FI of single or multiple con-current faults in plants and actuators simultaneously, without a pri…
This paper addresses the long-standing open problem of observability of mass and inertia plant parameters in the adaptive identification (AID) of second-order nonlinear models of 6 degree-of-freedom rigid-body dynamical systems subject to externally applied forces and moments. Although stable method…
This letter addresses the problem of on-line estimation and compensation of the hard-iron and soft-iron biases of a 2-axis magnetometer under dynamic motion, utilizing only biased measurements from a 2-axis magnetometer. The proposed adaptive observer formulates the relation between the true magneti
Ground-based teleoperation of robot manipulators for on-orbit servicing of spacecraft represents an example of high-payoff, high-risk operations that are challenging to perform due to high latency communications, with telemetry time delays of several seconds. In these scenarios, confidence of operat…
We propose a system for visually monitoring and servoing the cutting of a multi-layer insulation (MLI) blanket that covers the envelope of satellites and spacecraft. The main contributions of this paper are: 1) to propose a model for relating visual features describing the engagement depth of the bl…
On-orbit servicing of satellites is complicated by the fact that almost all existing satellites were not designed to be serviced. This creates a number of challenges, one of which is to cut and partially remove the protective thermal blanketing that encases a satellite prior to performing the servic…
This paper addresses the problem of underwater robotic vehicle navigation relative to moving or stationary sea ice. A brief review of previously-reported under-ice navigation methods is given, as well as a brief motivation for the use of under-ice robotic vehicles with precision navigation capabilit…
Nine degrees of freedom (DOF) inertial measurement units (IMUs) comprised of three-axis magnetometers, three-axis accelerometers, and three-axis angular rate sensors are commonly used in attitude and heading reference systems (AHRSs). Two classes of AHRSs exist: systems that estimate true-North head…
This paper reports a preliminary study for use of a fully dynamic vehicle process model in combined underwater communication and navigation (cooperative navigation) of underwater vehicles equipped with an acoustic modem, attitude, and depth sensors, but lacking a Doppler velocity log (DVL), and a su…
This paper reports a method and preliminary evaluation of a novel null-space least-squares parameter identification method for a fully nonlinear second -order 6-degree-of-freedom (DOF) dynamic process model of an underactuated underwater vehicle (UV) for which both the model parameters and the contr…
Teleoperation in extreme environments can be hindered by limitations in telemetry and in operator perception of the remote environment. Often, the primary mode of perception is visual feedback from remote cameras, which do not always provide suitable views and are subject to telemetry delays. To add
Despite the availability of increasingly more robust machine perception and control algorithms, human operators are still needed to directly control robotic systems in extreme environments where there is a high cost of failure. This paper reports a novel architecture for semi-autonomous teleoperatio…
This paper reports a novel stable adaptive attitude estimator and preliminary simulation results of a true-North gyrocompass system employing the attitude adaptive identifier and a commercially available low-cost inertial measurement unit (IMU) comprising a 3-axis fiber optic gyroscope (FOG) with a…
Six-degree of freedom (DOF) inertial measurement units (IMUs) are widely used for attitude estimation. However, such systems' accuracy is limited by the accuracy of calibration of bias, scale factors, and non-orthogonality of sensor measurements. This paper reports a stable adaptive estimator of mea…
This paper reviews the motivation, development, and use of underwater robotic vehicles designed for use in ice-covered waters, with special attention paid to the navigation systems employed for under-ice deployments. The scientific need for routine access under fixed and moving ice by underwater rob…
This paper reports a preliminary study of a method for combined underwater communication and navigation of underwater vehicles (cooperative navigation) equipped with an acoustic modem, attitude, and depth sensors, but lacking a Doppler velocity log (DVL), and a surface vehicle equipped with an acous
The ability to refuel satellites on-orbit using teleoperated robots could extend the life of satellite missions, potentially saving time and resources for both industry and space agencies. One critical step in the refueling process is to gain access to the satellite's fueling port by cutting through…
Direct teleoperation with multisecond time-delayed telemetry between master and slave is challenging for humans to perform. When controlling a holonomic robot with many degrees of freedom, operators may incidentally provide commands in an intended direction without realizing their mistake until rece…
This paper addresses the problem of ice-relative navigation of underwater robotic vehicles for oceanographic missions under moving sea ice. We define the ice-relative navigation problem and report a novel underwater robot vehicle, Nereid-UI, and its navigation system designed for under-ice oceanogra…