The paper describes a method for kinematic modeling of the Rocky 7 Mars rover. The model is derived for full six degree of freedom motions enabling movements in x,y,z directions, as well as pitch, roll and yaw rotations. Forward kinematic equations are derived using wheel Jacobian matrices. The individual matrices are then combined to form the composite equation for the rover. This equation is solved to obtain the rover position and heading in terms of measured wheel velocities and certain rocker joint angles. The inverse kinematics is derived relating the individual wheel velocities and steering angles to the desired forward velocity and turning rate of the rover. Due to the special kinematic configuration of Rocky 7, a geometric approach is developed to determine the steering angles.

This paper describes the design and implementation at the Jet Propulsion Laboratory of a small rover for future Mars missions requiring long traverses and rover-based science experiments. The small rover prototype, called Rocky 7, is capable of long traverses, autonomous navigation, and science instrument control. This rover carries three science instruments, and can be commanded from any computer platform from any location using the World Wide Web. In this paper we describe the mobility system, the sampling system, the sensor suite, navigation and control, onboard science instruments, and the ground command and control system. We also present key accomplishments of a recent field test of Rocky 7 in the Mojave Desert in California.

The development of a ground control station for Earth based control of the dexterous orbital servicing system (DOSS) is described. The DOSS flight test program provides a manipulator which is mounted on a multi-purpose experiment support structure (MPESS) in a Space Shuttle payload bay and may execute tasks from the MPESS or while held by the SSRMS manipulator. The DOSS demonstrates the ability to perform dexterous robotic operations both from an on-board control station and from an Earth-based control station. The initial prototype ground control station for DOSS is described.

The Serpentine Robot is a prototype hyper-redundant (snake-like) manipulator system developed at the Jet Propulsion Laboratory. It is designed to navigate and perform tasks in obstructed and constrained environments in which conventional 6-DOF manipulators cannot similarly function. This paper describes the Serpentine Robot mechanical design, a low level inverse kinematic algorithm for the joint assembly, a brief synopsis of control development to date, and the applications of this technology.

Recent advances in real-time 3-D computer graphics and hierarchically structured graphical user interfaces (GUI) enable development of very efficient graphics-based operator interfaces for telerobotic operations. This paper addresses potential benefits of such advanced graphics interfaces to telerobotic servicing and inspection, emphasizing operator efficiency and system safety. Specifically, the authors report on calibrated 3-D graphics displays and GUIs developed and applied to an advanced teleoperation system and a remote surface inspection system at the Jet Propulsion Laboratory.

Orbital replacement unit (ORU) changeout experiments were performed with the JPL/NASA telerobot testbed system for three different control modes: force reflecting teleoperation (FR), shared compliant control (SCC), and autonomous control (AC). In FR, the operator was provided with kinesthetic force feedback, feeling contact forces through a force-reflecting hand controller. In SCC, the operator controlled a compliant robot, where the robot compliance was implemented by an autonomous compliant control force feedback. In AC, telemanipulation tasks were performed autonomously by using a sequence of macros. Experimental results indicate that SCC greatly reduces the magnitudes and durations of contact forces as compared to FR. AC took the least time to complete the ORU changeout task and, with appropriate operator intervention capabilities, it could be very pleasant to use in some applications with well-structured task environments.>

A description is given of a complete robot control facility built at the CIT Jet Propulsion Laboratory as part of a NASA telerobotic program to develop a state-of-the-art robot control environment for laboratory-based spacelike experiments. This system has the following features: separation of the computing facilities into local and remote sites, autonomous motion generation in joint or Cartesian coordinates, dual-arm force reflecting teleoperation with voice interaction between the operator and the robots, shared control between the autonomously generated motions and operator controlled teleoperation, and dual-arm coordinated trajectory generation. The system has been used to carry out realistic experiments such as the exchange of an orbital replacement unit, bolt turning, and door opening, using a mixture of autonomous actions and teleoperation, with either a single arm or two cooperating arms.>

Preliminary results are reported from efforts to design and develop a robotic system that will accept and execute commands from either a six-axis teleoperator device or an autonomous planner or combine the two. Such a system should have both traded and shared control capability. A sharing strategy is presented whereby the overall system, while retaining positive features of teleoperated and autonomous operation, loses its individual negative features. A two-tired shared control architecture is considered here, consisting of a task level and a servo level. Also presented is a computer architecture for the implementation of this system, including a description of the hardware and software.>

Autonomous robot task execution requires that the end effector of the robot be positioned accurately relative to a reference world-coordinate frame. The authors present a complete formulation to identify the actual robot geometric parameters. The method applies to any serial link manipulator with arbitrary order and combination of revolute and prismatic joints. A method is also presented to solve the inverse kinematic of the actual robot model which usually is not a so-called simple robot. Experimental results performed by utilizing a PUMA 560 with simple measurement hardware are presented. As a result of this calibration a precision move command is designed and integrated into a robot language, RCCL, and used in the NASA Telerobot Testbed.>

This paper describes the architecture and Ada language implementation of a process-level run-time control subystem for the Jet Propulsion Laboratory (JPL) telerobot system. The concept of run-time control in a combined robot-teleoperation environment is examined and the telerobot system at JPL is described. An Ada language implementation of the JPL Telerobot Run-Time Controller (RTC) is described by highlighting the functional behavior of the subsystem, defining the internal modules, and providing a functional flow time sequence of internal module activity.