Construction of a Leg Mechanism

This is a series of four videos that show how to:

  1. Specify three positions for the foot of a leg consisting of a hip and knee joint;
  2. Use three position synthesis to design a four-bar function generator to guide the hip joint;
  3. Then use three position synthesis to design a second four-bar function generator to guide the knee joint;
  4. And finally assemble the linkage to determine the trajectory of the foot. Adjusting the lengths of the leg segments, the position of the hip, the specified positions of the input cranks, and the position of the coupler attachments to the input cranks vary the resulting foot trajectory. An example leg mechanism is shown at the end of this video.

Part 1:4 Setting up the design

Part 2:4 Synthesis of the hip function generator.

Part 3:4 Synthesis of the knee function generator.

Part 4:4 Assembly of the leg mechanism, exploration of design variations, and an example final leg design.

Walking Robot Student Project

Walking Machine Class Projects: Ohio State ME 5751

Prof Haijun Su at Ohio State University had his students design walking machines for their final project in ME 5751. Here are videos of four project teams from that event.

Team A:

Team B:

Team C:

Team D:


Strider and TrotBot at

Just after I published my book Kinematic Synthesis of Mechanisms with its emphasis on leg mechanisms, I found two more interesting eight-bar legs from the designers at

This is a Geogebra animation of the leg mechanism for the Strider walker. It is a symmetrical design that allows the formation of a second foot assembly by simply adding two more bars.

Strider leg mechanism.

This is an animation of the leg mechanism in the TrotBot walker.

TrotBot leg mechanism.


Introduction to Theoretical Kinematics, paperback on

I am pleased to report that a paperback version my book Introduction to Theoretical Kinematics: the mathematics of movement is on-line with I have updated it to reflect current terminology in Robotics and to correct all of the errors that I could identify. Please select the link Introduction to Theoretical Kinematics.

Design of Linkages to Draw Curves, GRASPLab Seminar

On May 8, 2018, I was pleased to give a seminar at the University of Pennsylvania GRASPLab:  McCarthy Seminar.

They also videotaped my lecture.  Here it is:

Robotics Handbook

Robot Ethics

Robotics Handbook

Springer Handbook of Robotics

I found this excerpt of the TEDx talk by Bruno Siciliano describing the growing research area of Roboethics to be fascinating and important. Prof. Siciliano is the Director of the ICAROS Center at the Universita degli Studi di Napoli Federico II. He is co-editor with Oussama Khatib of the first and second editions of the Springer Handbook of Robotics. The entire talk is available at the link Robotics and Napoli.

Mechanisms and Robotics Conference

2016 Mechanisms and Robotics Conference

Mechanisms and Robotics Conference

Symposia organized for the 2016 Mechanisms and Robotics Conference

The 2016 Mechanisms and Robotics conference is part of International Design Engineering Technical Conferences organized by ASME International in Charlotte, North Caroline, August 22-24.

Plenary speaker Bernard Roth is the Academic Director of Stanford University’s and the author of the Achievement Habit.

For some reason, ASME has broken these links to the 2016 IDETC conference, but you can find out more about each of the symposia at the conference overview link: 2016 ASME Mechanism and Robotics Conference Overview.  Then select the Expand all Symposia Link to see the sessions and a list of papers.


Virgo 2 SUTD

Rolling Robot at SUTD

Virgo 2 SUTD

Virgo 2 SUTD

A research team including Profs. GimSong Soh, Kristin Wood and Kevin Otto at Robotics Innovation Lab at the Singapore University of Technology and Design has developed a rolling robot about the size of a baseball. The design and motion planning of this robot, Virgo 2.0, was presented at the Mechanisms and Robotics Conference which was part of the 2015 ASME Design Engineering Technical Conferences, August 2-5, in Boston, MA. A demonstration of the Virgo 2.0 moving through a figure eight path around obstacles is shown in the video below.

Laval Robot

An Interesting Planar Robot at Laval

Students of Prof. Clement Gosselin at the Laval University Robotics Laboratory demonstrate a four-degree of freedom planar robot. I particularly like the demonstration of its use as a gripper that does a cartwheel just for fun.

Tensegrity Robot

Tensegrity Robotics at UC Berkeley

Students in Professor Alice Agogino’s Berkeley Emergent Space Technologies Laboratory, the BEST Lab, working on motion planning for their tensegrity robot.