JPL’s ATHLETE Rover Walks, Rolls, and Slides

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Athlete-Rover-Nasa

JPL’s ATHLETE Rover (image from paper cited below)

The ATHLETE Rover is a mixture of a wheeled rover and a walking robot, or better a walking truck, created by engineers at Jet Propulsion Laboratory to be used for manned and unmanned missions to the moon. ATHLETE, which stands for All-Terrain Hex-Limbed Extra-Terrestrial Explorer, is a six-legged walker that is taller than a person. The walker also rolls since it has powered wheels at the end of each limb. This allows the ATHLETE great mobility over changing terrain.

An innovation that comes from the leg-wheel combo is the Sliding Gait, which is a mode of transport more efficient than walking that can be used over loose or steep terrain where driving is impossible. Sliding Gait uses some of the articulated legs as anchors while others do the walking or sliding, like skating. This allows for quicker more responsive movement of the robot. The ATHLETE is to be remote controlled from earth or by astronauts on the moon, so the many different ways the machine can travel give more options to a remote user to navigate tricky terrain.

athlete-rover-2

ATHLETE at work (image from paper cited below)

Motion planning is critical to the operation of ATHLETE because it is both a walker, a rover and something in between, so it takes some work to plan out each step. Footfall is the software that assists the remote driver in planning each step. It uses “telemetry from the robot, such as joint angles and stereo camera image pairs, and generates 3D terrain map,” computes a sequence of movement commands and presents an animated preview to the driver. Footfall makes it possible for this big robot to really move.

Citations:

“FootFall: A Ground Based Operations Toolset Enabling Walking for the ATHLETE Rover,” by Vytas SunSpiral, Daniel Chavez-Clemente, Michael Broxton, Leslie Keely, Patrick Mihelich, David Mittman, and Curtis Collins.

“Sliding Gait for Athlete Mobility,” NASA Techbrief, This work was done by Julie A. Townsend, Curtis L. Collins, and Jeffrey J. Biesiadecki of Caltech for NASA’s Jet Propulsion Laboratory.

Read more about the ATHLETE Rover at JPL’s Website

Wearable Robotics Put Spring in Your Step

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Wearable electronics or “wearables” are seen as the next great wave of technology and commerce. Much of the popular talk about these kinds of products revolves around things like fitness trackers, augmented reality devices, and other machines you can wear that interact with, track, or add on to your experience with the world around you. Thomas Sugar, a professor at Arizona State University Polytechnic Campus and a wearable robotics expert works on a different kind of wearable.

Along with his colleagues and students, he has developed a new generation of powered prosthetic devices that can be used for rehabilitation and as prosthetics for amputees. He works on spring-based robots that enhance human mobility based on lightweight energy storing springs that allow for a more responsive and therefore more functional human gait. His devices make position control calculations 1,000 times per second to make the prosthetics as human as possible.

springactive-odyssey
Sugar starts from a “human being first” research perspective since his devices must be wearable and efficient. In his devices, spring power and motor power combine to create a powered system that gives prosthetic ankles the “push off” and “toe pick up” they need in order to mimic the function of human ankles.

His idea of a robotic tendon is much more efficient than a direct drive system, which would require more electricity and larger, more powerful motors.   In fact, his innovation uses half the required energy of a direct drive system powered prosthetic ankle.

springactive-spark
In a different device attached to the ankle Sugar uses able-bodied movement to harvest energy from walking. His company SpringActive developed a boot attachment with the military in mind that turns walking into back up power for batteries with negligible metabolic cost.

The real world and commercial applications for this kind of research are far reaching.   For more on Thomas Sugar’s and his colleagues’ work, visit SpringActive.com and http://innovation.asu.edu/

21st Century Kinematics

Workshop on 21st Century Kinematics

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21st Century Kinematics

21st Century Kinematics

The NSF Workshop on 21st Century Kinematics at the 2012 ASME IDETC Conference in Chicago, IL on August 11-12, 2012 consisted of a series of presentations and a book of supporting material prepared by the workshop contributors.

The book is now available at amazon.com: 21st Century Kinematics–The 2012 NSF Workshop.

And here are the seven primary presentations given at the workshop.

  1. Computer-Aided Invention of Mechanisms and Robots. J. Michael McCarthy, Professor, University of California, Irvine.
  2. Mechanism Synthesis for Modeling Human Movement. Vincenzo Parenti-Castelli, Professor, University of Bologna.
  3. Algebraic Geometry and Kinematic Synthesis. Manfred Husty, Professor, University of Innsbruck.
  4. Kinematic Synthesis of Compliant Mechanisms. Larry Howell, Professor, Brigham Young University.
  5. Kinematics and Numerical Algebraic Geometry. Charles Wampler, Technical Fellow, General Motors Research and Development.
  6. Kinematic Analysis of Cable Robotic Systems. Vijay Kumar, Professor, University of Pennsylvania.
  7. Protein Kinematics. Kazem Kazerounian, Professor, University of Connecticut.

Colleagues joined in with two additional presentations:

Many thanks to the contributors and the attendees for an outstanding workshop.

Update: The presentation links have been fixed.

Kinematics and Polynomials

Kinematics and Polynomials–available on a Mac

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Until yesterday, my iBooks Introduction to Theoretical Kinematics and Kinematics and Polynomials were available only on the iPad, but now with OSX Mavericks they are available on any Mac. Please give it a try. You can download a sample at this link: Kinematics and Polynomials sample.

Mechanical Characters

Mechanical characters

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Disney Research guides two degree-of-freedom open chains using the coupler curve of a geared five-bar linkage to obtain geared seven-bar and nine-bar linkages, which they use to move the front and rear legs of their Cyber Tiger. By connecting the driving gears of the four legs, they obtain a one degree-of-freedom system that animates the Cyber Tiger.

The computational design system uses an optimization routine to adjust the coupler curve of the five-bar linkage to approximate a given curve in order to guide the system in a desired movement. The results are terrific, and look a lot like the mechanical toys of the past. Select this link for more information.

Six-bar linkages

Six-bar Linkage Design for Mechanical Computation

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Six-bar linkages

Six-bar linkages

Our paper Numerical Synthesis of Six-bar Linkages for Mechanical Computation provides the mathematical theory that underlies the synthesis of a six-bar linkage with an input-output relationship that approximates a specified function. This describes how the Stephenson III six-bar linkage that sets the elevation for a ballistic trajectory was designed.

Waldron Celebration

Waldron Fest: May 16-17, 2013

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Waldron Inspires

Waldron Inspires

This poster was prepared as a gift to Ken Waldron on his 70th birthday and given to him at a conference organized in his honor. Anuj Taneja generated the SolidWorks model in 2006 from the original drawings of the Adaptive Suspension Vehicle. I recently found the electronic files and Kaustubh Sonawale generated the four-view drawing. The ASV is an important feat of engineering and the stories shared by those who worked on it were wonderful.

Introduction to Theoretical Kinematics

Introduction to Theoretical Kinematics

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Introduction to Theoretical Kinematics


Introduction to Theoretical Kinematics

My 1990 book is now on-line as an iBook. It is available as of March 31, 2013. This 2013 version has corrections to errors and language, and includes a glossary and animations of various linkage systems. I hope you like it.

You can see it at the link: Introduction to Theoretical Kinematics.

Six-bar gripper with fine adjustment

Six-bar gripper with fine adjustment

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This is a robotic gripper designed by Andrea Carli and Kaustubh Sonawale. It uses a six-bar linkage for the primary movement and a slider adjustment to provide a gripping fine movement.

Workshop Schedule: 21st Century Kinematics

21st Century Kinematics: Workshop Schedule

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Here is the schedule for the IDETC/NSF Workshop on 21st Century Kinematics:

Workshop Schedule: 21st Century Kinematics

Workshop Schedule: 21st Century Kinematics