The ParkourBot climbs in a planar reduced-gravity vertical chute by leaping back and forth between the chute's two parallel walls. The ParkourBot is comprised of a body with two springy legs and its controls consist of leg angles at touchdown and the energy stored in them. During flight, the robot stores elastic potential energy in its springy legs and then converts this potential energy in to kinetic energy at touchdown, when it “kicks off” a wall. This paper describes the ParkourBot's mechanical design, modeling, and open-loop climbing experiments. The mechanical design makes use of the BowLeg, previously used for hopping on a flat ground. We introduce two models of the BowLeg ParkourBot: one is based on a nonzero stance duration using the spring-loaded inverted pendulum model, and the other is a simplified model (the simplest parkour model, or SPM) obtained as the leg stiffness approaches infinity and the stance time approaches zero. The SPM approximation provides the advantage of closed-form calculations. Finally, predictions of the models are validated by experiments in open-loop climbing in a reduced-gravity planar environment provided by an air table.

The ParkourBot is an efficient and dynamic climbing robot. The robot comprises two springy legs connected to a body. Leg angle and spring tension are independently controlled. The robot climbs between two parallel walls by leaping from one wall to the other. During flight, the robot stores elastic energy in its springy legs and automatically releases the energy to "kick off" the wall during touch down. This paper elaborates on the mechanical design of the ParkourBot. We use a simple SLIP model to simulate the ParkourBot motion and stability. Finally, we detail experimental results, from open-loop climbing motions to closed-loop stabilization of climbing height in a planar, reduced gravity environment.

The prismatic cube style of modular robot is a promising design for realizing self-reconfigurable 3D lattices. Cubic lattices with prismatic transitions simplify many aspects of the hardware and planning control needed for reconfiguration. Despite much research on how cubic modules can coordinate to reconfigure, until now these transitions have not been fully demonstrated in hardware.We describe our movement primitives for both orthogonal and convex corner transitions with prismatic cube modules. We discuss the design of a hardware module capable of performing these transitions, as well as assess the performance of this hardware in an initial demonstration of these transitions.

Small robots have the potential to access confined spaces where humans cannot go. However, the mobility of wheeled and tracked systems is severely limited in cluttered environments. Snake robots using biologically inspired gaits for locomotion can provide better access in many situations, but are slow and can easily snag. This paper introduces an alternative approach to snake robot locomotion, in which the entire surface of the robot provides continuous propulsive force to significantly improve speed and mobility in many environments.

We present a refined, second-generation design, construction and integration, of a compact hyper-redundant snakelike robot, called "Woodstock." This robot has substantial advantages over our previous design iteration, "Snoopy," in terms of cost and performance. The robot is composed of six actuated universal joints which are serially chained to construct a twelve degrees of freedom snake-like robot optimized for strength and compactness. Any joint in the robot is strong enough to produce a torque that is capable of cantilevering the entire robot. This paper also presents the low-level system- control architecture, which is based on a high-speed RS-485 data bus; this allows the entire system to be operated with only two power and two data wires. The system is controlled from a remote computer on a wireless network and can also run over the Internet.

In January 2004, NASA began a bold enterprise to return to the Moon, and with the technologies and expertise gained, press on to Mars. The underlying Vision for Space Exploration calls for a sustained and affordable human and robotic program to explore the solar system and beyond; to conduct human expeditions to Mars after successfully demonstrating sustained human exploration missions on the Moon. The approach is to "send human and robotic explorers as partners, leveraging the capabilities of each where most useful." Human-robot interfacing technologies for this approach are required at readiness levels above any available today. In this paper, we describe the HRI aspects of a robot supervision architecture we are developing under NASA's auspices, based on the authors' extensive experience with field deployment of ground, underwater, lighter-than-air, and inspection autonomous and semi-autonomous robotic vehicles and systems.

In this paper, we present a method for controlling a motorized, string-driven marionette using motion capture data from human actors. The motion data must be adapted for the marionette because its kinematic and dynamic properties differ from those of the human actor in degrees of freedom, limb length, workspace, mass distribution, sensors, and actuators. This adaptation is accomplished via an inverse kinematics algorithm that takes into account marker positions, joint motion ranges, string constraints, and potential energy. We also apply a feedforward controller to prevent extraneous swings of the hands. Experimental results show that our approach enables the marionette to perform motions that are qualitatively similar to the original human motion capture data.

In this work we introduce a new concept of a search and rescue robotic system that is composed of an elephant trunk-like robot mounted on a mobile base. This system is capable not only of inspecting areas reachable by the mobile base but also to inspect unreachable areas such as small cracks, and pipes, using the camera mounted on its elephant trunk robot. In the report we describe the mechanical structure of the elephant trunk robot, the kinematic analysis of the structure, the robot control, and its human interface systems.

We describe the mechanical and electronic design of a precision, 2-DOF robot manipulator. The manipulator is one of a wide variety of modular robotic agents in the minifactory, a rapidly deployable precision assembly system under development in our laboratory. The manipulator, in cooperation with another type of 2-DOF robot, termed a courier, can perform 4-DOF assembly operations emulating a SCARA robot. This arrangement provides increased precision, higher throughput, smaller footprint, and increased flexibility relative to the SCARA robot.

We develop a dynamic model of the steering and actuation mechanism of Gyrover, a single-wheel robot which can be considered as a single wheel, actuated through a spinning flywheel attached through a two-link manipulator at the wheel bearing and a drive motor. The spinning flywheel acts as a gyroscope to stabilize the robot, and at the same time it can achieve steering. We develop a dynamic model, investigate its motion equation, and nonholonomic constraints, and present a simulation study. The work is significant in understanding this type of dynamically stable but statically unstable system, and in developing automatic control of the system.

We are developing a novel concept for mobility, and studying fundamental research issues on dynamics and control of the mobile robot. The robot, called Gyrover, is a single-wheel vehicle with an internal gyroscope that provides mechanical stabilization and steering capability. This configuration conveys significant advantages over multi-wheel, statically stable vehicles, including good dynamic stability and insensitivity to attitude disturbances; high manoeuvrability; low rolling resistance; ability to recover from falls; and amphibious capability. In this paper we present the design, analysis and implementation of the robot, as well as the associated research issues and potential applications.

A rapidly deployable manipulator system combines the flexibility of reconfigurable modular hardware with modular programming tools, allowing the user to rapidly create a manipulator which is custom-tailored for a given task. This article describes two main aspects of such a system, namely, the reconfigurable modular manipulator system (RMMS) hardware and the corresponding control software.

We present a novel mobile manipulator concept called the dual-use mobile detachable manipulator, or (DM)/sup 2/, for early construction and maintenance tasks in lunar stations. The robot consists of a wheeled rover, or mobile base and a detachable manipulator arm. The arm is symmetric, with a gripper at each end. When the arm attaches to the mobile base by grasping a handle with one of its grippers, the robot becomes a mobile manipulator and can perform exploration tasks such as collecting soil samples, surveying the lunar surface, and transporting tools and supplies. When the robot nears a lunar center structure such as a manufacturing center or a fuel tank, the manipulator arm can detach from the base and walk hand-over-hand, by grasping a series of handles on the structure, to perform tasks such as structure inspection, parts delivery, and simple assembly tasks. The paper discusses the concept and its advantages, the system under development, and its software architecture.

The control of flexible arms with friction in the joints is studied. A method to identify the dynamics of a flexible arm from its frequency response (which is strongly distorted by Coulomb's friction) is proposed. A robust control scheme that minimizes the effects of this friction is presented. The scheme consists of two nested feedback loops: an inner loop to control the motor position and an outer loop to control the tip position. It is shown that a proper design of the inner loop eliminates the effects of friction while controlling the tip position and significantly simplifies the design of the outer loop. The proposed scheme is applied to a class of lightweight flexible arms, and the experiments show that the control scheme results in a simple controller. As a result, the computations are minimized and, thus, high sampling rates may be used.>

Self-Mobile Space Manipulator (SM/sup 2/) is a simple, 5-DOF (degree-of-freedom), 1/3-scale, laboratory version of a robot designed to walk on the trusswork and other exterior surfaces of Space Station Freedom. It will be capable of routine tasks such as inspection, parts transportation, and simple maintenance procedures. The authors have designed and built the robot and gravity compensation system to permit simulated zero-gravity experiments. They have developed the control system for the SM/sup 2/ including control hardware architecture and operating system, control station with various interfaces, hierarchical control structure, multiphase control strategy for step motion, and various low-level controllers. The system provides operator-friendly real-time monitoring, and robust control for 3D locomotion movements of the flexible robot.>

We have developed a light-weight space manipulator, Self-Mobile Space Manipulator (SM'), in the Robotics Institute at Carnegie Mellon University. SM' is a 7-degreeof-freedom (DOF), 1/3-scale, laboratory version of a robot designed to walk on the trusswork and other exterior surfaces of Space Station Freedom, and to perform manipulation tasks that are required for inspection, maintenance, and construction. Combining the mobility and manip ulation functions in one body as a mobile manipulator, SM2 is capable of routine tasks such as inspection, parts transportation, object lighting, and simple assembly procedures. The system will provide assistance to astronauts and greatly reduce the need for astronaut extra-vehicular activity (EVA). This paper discusses the robot hardware development, gravity compensation system, control structure and teleoperation functions of the SM2 system, and demonstrates its capabilities of locomotion and manipulation in space applications.

Tip-position control of a flexible arm with friction in the joints is carried out. The control scheme is based on two nested feedback loops, an inner loop to control the position of the motor and an outer loop that controls the tip position of the flexible arm. The inner loop is controlled by a high-gain controller to remove the effects of friction. A control law partitioning scheme that partitions the control law into a model-based portion and a servo portion is used for the control of the outer loop. To make the arm follow the desired trajectory without any delay, a feedforward term is added to the control law. The control scheme is experimentally evaluated on two very lightweight flexible arms.>

A method for controlling single-link, lightweight, flexible manipulators is proposed. The objective of this method is to control the tip position of the flexible manipulator in the presence of joint friction and changes in the payload. Both linear and nonlinear friction are overcome using a very robust control scheme that is based on two nested feedback loops: an inner loop to control the position of the motor and an outer loop to control the tip position. Changes in the load are compensated by decoupling the dynamics of the system and then applying a very simple adaptive control for the tip position. This results in a quite simple control law that requires minimal computing effort and thus can be used for real-time control of flexible arms.>

Simple locomotion algorithms provide balance for machines that run on one leg. The generalization of these one-leg algorithms for control of machines with several legs is explored. The generalization is quite simple when muitilegged systems run with gaits that use the support legs one at a time. For these gaits the one-leg algorithms can be used to control multilegged running. The concept of a virtual leg is introduced to further extend the approach to gaits that use the legs in pairs, such as the trot, the pace, and the bound. These quadruped running gaits map into gaits that use one virtual leg for support at a time, for which the one-leg algorithms can provide control. This approach was used in laboratory experiments to control a quadruped machine that runs with a trotting gait.