Electrical and Computer Engineering

The OCTOR project - named for soft robotic manipulators - looks for ways to bring the remarkable capabilities of muscular hydrostats such as octopus arms to robotics by designing, analyzing, and building continuum robots.

Introduction - news - publications - multimedia - software

Inspired by elephant trunks, mammalian tongues, and octopus arms, appendages which possess remarkable manipulation abilities without a typical skeletal structure, continuum robots seek to mimic the astonishing abilities of these organisms through designs which lack the rigid links which compose traditional robots. Just as an octopus explores under rocks and in dark holes by feeling with its arms, so also continuum trunks could be used in urban search and rescue operations in the unstructured, confined environments of collapsed buildings. By encircling objects of widely varying sizes and a priori unknown shapes, continuum robots may utilize whole-arm grasping to manipulate objects too large, too fragile, or too unstructured for traditional parallel-jaw grippers in a manner similar to the abilities evidenced by elephant trunks as shown in Fig. 1 on the left.

(a)

(b)

Fig. 1. In (a), the OctArm continuum manipulator grasps a traffic cone. Shown here, it replaces the end-effector of a Foster-Miller Talon robot. In (b), the two-section Air-Octor continuum robot is shown.

The OCTOR project provides both a mathematical foundation for describing and understanding continuum robots and a set of practical implementation techniques in the form of software and hardware which validate this theory. For example, the project defines the trunk as in arc of a circle parameterized by trunk length s, curvature κ, and direction of curvature φ as shown in a movie behind the figure on the left. This derivation can be applied to a trunk composed of three actuators fixed between parallel plates, as shown in Fig. 2a, such as OctArm in Fig. 1a. It can also be applied to trunks formed from a single chamber and controlled by cables, as diagrammed in Fig. 2a, such as Air-Octor shown in Fig. 1a. Using the symbolic and code-generation capability of Maple, this mathematical model is then transformed into C code which provides wireless, real-time control of the trunk using a joystick and a laptop. A 3-D model of the trunk provides feedback on the shape of the trunk

(a)

(b)

Fig. 2. On the left, (a) illustrates a trunk composed of three pressurized chambers (McKibben actuators) connected by a single plate. On the right, (b) shows that a trunk is composed of a pressurized chamber surrounded by three cables which control the trunk's shape.

Introduction - news - publications - multimedia - software

See the Canadian Discovery channel's take on OCTOR on their Daily Planet.
SlashDot mentioned OCTOR in a post.
LiveScience published an article about OCTOR.
NewScientistTech also published an article about OCTOR.

Introduction - news - publications - multimedia - software

Journal publications

B. A. Jones and I. D. Walker, “Practical kinematics for real-time implementation of continuum robots,” IEEE Transactions on Robotics, vol. 22, no. 6, Dec. 2006, pp. 1087-1099 (paper) (cites).

B. A. Jones and I. D. Walker, “Kinematics for multi-section continuum robots,” IEEE Transactions on Robotics, vol. 22, no. 1, Feb. 2006, pp. 43-55 (paper in color) (as published) (animated figures) (video of kinematics derivation) (corrections) (cites).

W. McMahan, B. A. Jones, and I. D. Walker, “Robotic manipulators inspired by cephalopod limbs,” The Journal of Engineering Design and Innovation, vol. 1P, paper 01P2, December, 2005 (paper) (cites).

Conference publications

B. A. Jones and I. D. Walker, “Limiting-case analysis of continuum trunk kinematics,” Proceedings of the International Conference on Robotics and Automation, April 2007, Rome, Italy, pp. 1363-1368 (paper as published) (corrected paper) (presentation).

B. A. Jones and I. D. Walker, “Three-Dimensional modeling and display of continuum robots,” Proceedings of the International Conference on Intelligent Robotics and Systems, October 2006, Beijing, China, p. 5872-5877 (corrected paper) (as published) (presentation).

B. Holbrook, M. Csencsits, W. McMahan, V. Chitrakaran, M. Grissom, M. Pritts, B. A. Jones, C. D. Rahn and I. D. Walker, “Field experiments with the OctArm continuum manipulator,” video 040 in Proceedings of the International Conference on Intelligent Robotics and Systems, October 2006, Beijing, China (in WMV format).

B. A. Jones, W. McMahan, and I. D. Walker, “Practical kinematics for real-time implementation of continuum robots,” Proceedings of the International Conference on Robotics and Automation, May 2006, Orlando, Florida, pp. 1840-1847 (paper).

W. McMahan, B. A. Jones, V. Chitrakaran, M. Csencsits, M. Grissom, M. Pritts, C. D. Rahn and I. D. Walker, “Field trials and testing of the Octarm continuum manipulator,” Proceedings of the International Conference on Robotics and Automation, May 2006, Orlando, Florida, pp. 2336-2341 (paper) (cites).

B. A. Jones, M. Csencsits, W. McMahan, V. Chitrakaran, M. Grissom, M. Pritts, C. D. Rahn and I. D. Walker, “Grasping, manipulation, and exploration tasks with the OctArm continuum manipulator,” video in Proceedings of the International Conference on Robotics and Automation, May 2006, Orlando, Florida (video).

M. Csencsits, B. A. Jones, W. McMahan, V. Iyengar, and I. D. Walker, “User interfaces for continuum robot arms,” Proceedings of the International Conference on Intelligent Robotics and Systems, August 2005, Edmonton, Canada, pp. 3011-3018 (paper) (presentation) (related video) (cites).

W. McMahan, B. A. Jones, I. D. Walker, “Design and implementation of a multi-section continuum robot: Air-Octor,” Proceedings of the International Conference on Intelligent Robotics and Systems, August 2005, Edmonton, Canada, pp. 3345-3352 (paper) (video in DIVX format) (cites).

B. A. Jones and I. D. Walker, “A new approach to Jacobian formulation for a class of multi-section continuum robots,” Proceedings of the International Conference on Robotics and Automation, May 2005, Barcelona, Spain, pp. 3279-3284 (paper) (presentation) (video) (overview) (cites).

B. A. Jones, W. McMahan, and I. D. Walker, “Design and Analysis of a Novel Pneumatic Manipulator,” Proceedings of the 3^rd IFAC Symposium on Mechatronic Systems, Sept. 6, 2004, Sydney, Australia, pp. 745-750 (paper) (presentation) (video) (cites).

W. McMahan, B. A. Jones, I. D. Walker, V. Chitrakaran, A. Seshadri, and D. Dawson, “Robotic manipulators inspired by cephalopod limbs,” Proceedings of the CDEN Design Conference, July 2004, Montreal, Canada, pp 1-10 (paper) (presentation) (video) (cites).

Thesis / technical reports

Ph.D. Thesis (August 2005): Kinematics and implementation of continuum manipulators (paper) (presentation) (videos of kinematics and implementation)

Bryan A. Jones, “Analysis of a Novel Pneumatic Manipulator,” Technical Report, February 2004, Clemson University (PDF).

Introduction - news - publications - multimedia - software

Field trials of the OctArm continuum manipulator mounted on a Talon mobile platform reveal the wide variety of capabilities of this type of robot.	This video shows grasping, manipulation, and exploration tasks with the OctArm continuum manipulator.
This video explaining trunk kinematics reveals the mathematical formulation behind continuum manipulators.	An animated figure reveals the crucial difference between an older formulation for a continuum trunk compared to the method developed [here]: the new formulation is torsion-free, which matches the physical construction of the robot, in contrast to the earlier torsional formulation.
This video illustrates various joystick control modes for a continuum robot and shows the ways in which the robot bends and moves.	A video of a 3-D model of a continuum trunk and joystick also illustrates how these control modes operate.
The Coke thief is devious and wily! See what we caught on video.	A demonstration of a first prototype of a continuum trunks shows that the trunk can both bend and extend or contract in length.
A fixed-length continuum-like robot grasps an object.	Playing with our biological inspiration, an octopus.

Introduction - news - publications - multimedia - software

Code (.cpp and .h) for a NURBS-based formulation of a continuum trunk produces a real-time, 3-D realization of the trunk which specifies the shape of trunk as a bent cylinder, rather than approximating it as a large number of rigid-link segments. This code (.cpp and .h) depends on the Coin library, a platform-independent implementation of OpenInventor. See the Coin website for instruction on compiling and linking again their libraries.