Six-Legged Mechanical Walkers: Spring 2020 Highlights

The design of these four-legged walkers uses two coordinated function generators to drive the hip and knee joints to achieve the desired foot trajectory. This differs from Jansen’s leg mechanism in the following ways: (i) separate cranks can be used to drive the hip and knee joints, rather than the same crank driving both joints; (ii) the drive of the hip joint need not be connected at the knee but can connect any where on the upper leg; and (iii) a true parallelogram is used to connect the drive around the hip down to the knee, whereas Jansen’s connection has one side slightly larger for both pairs (39.3, and 39.4 for one pair of sides, and 40.1 and 36.7 for the other pair). So these leg mechanisms can be viewed as generalizations of Jansen’s design.

Stable gait for these walkers can be achieved by coordinating three legs at a time to form a tripod gait.  Please see this video showing walkers designed by my students to be a crocodile, rhinoceros, bug, legged container and the Star Wars All-Terrain Tactical Enforcer, known as AT-TE. These assemblies of six 10-bar linkages connected by a gear train of as many as 18 gears posed a challenge to SolidWorks motion analysis for my students. We will get better at this.

Prototype Four-Legged Mechanical Walker

Kevin Chen and Arwa Tizani designed this four-legged mechanical walker using Curvature theory to identify a flat-sided coupler curve of a four-bar linkage. This curve was positioned to be the foot trajectory of the leg mechanism using a skew-pantograph.

Kevin collected the parts and assembled the walker. Here are his photos and video of its performance:

Fall 2019 Mechanical Walker Prototypes

I was pleased to have an enthusiastic group of graduate students work with me on the design of four-legged walkers as the final project for MAE 245 Kinematic Synthesis. Each of the teams designed a four-bar linkage using Curvature Theory to obtain a coupler curve with a flat portion that could be used as the foot trajectories for the legs of the walker.

Then, they placed the coupler curve in position to form the feet of a walker by using a skew pantograph for the front legs and rectilinear six-bar linkages for the rear legs. I required this particular choice of the type of legs, simply because I was not sure which would work better.

This video shows the operation of their design prototypes. They all work as designed, though we have more work to do on their fabrication in order to improve performance.

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:

Beijing Walking Robot

Design Research in China: Beijing

This video shows the excellent research in design at universities in Beijing.  This is the final of five videos highlighting design research across China taken during a visit in September 2016.

 

For our colleagues in China, here is a link to a YouKu version.

Beijing Design Research

Beijing Design Research

2017 MR Conference

2017 ASME Mechanisms and Robotics Conference

The program for the 2017 ASME Mechanisms and Robotics Conference is now on-line. You can access it at the link: ASME MR Conference

The papers from the UCI Robotics and Automation Lab are:

2017 MR Conf Program

2017 MR Conf Program

Design Research Changzhou

Design Research in China: Changzhou

Our trip through China concluded at a conference and workshop at Changzhou University. This video highlights the Changzhou conference on innovation in Robotics and Intelligent Manufacturing, the beauty of the city of Changzhou, and a rainy night in Shanghai.

Our colleagues in China can see this video on YouKu at: Design Research in China: Changzhou

Changzhou YouKu

Changzhou YouKu

Design Research Dalian

Design Research in China: Dalian

Design Research Dalian

Design Research Dalian

This is the third of five videos highlighting design research across China.  This captures the beauty of Dalian, a city on the Yellow sea, and the excellent research in precision machine design by colleagues and their students at Dalian University of Technology.

Here is a link to this video on Youku for our colleagues in China:
http://v.youku.com/v_show/id_XMTg5MDg4MzI0NA==.html

Youku Dalian

Youku Dalian

Design Research Xian

Design Research in China: Xi’an

Design Research Xian

Design Research Xian

This video of our visit to Xi’an captures the beauty of the city and its surroundings, as well as the personality of the excellent professors and students at Xidian University.

For our colleagues in China, here is a link to a Youku version of this video: http://v.youku.com/v_show/id_XMTg2MzQ5NDI4MA==.html

Youku Xian Video

Youku Xian Video

Trifolium prototype

Prototype of the Trifolium Mechanism

Trifolium prototype

Trifolium prototype

Yang Liu and Peter Yang designed and built this physical prototype of our Trifolium mechanism.  It is fabricated from ABS using the Stratasys Fortus system in UCI’s Institute for Design and Manufacturing Innovation.

Our Chinese colleagues can view this video on Youku at the link: http://v.youku.com/v_show/id_XMTg2MzQ2MjE5Mg==.html

Youku Trifolium Prototype

Youku Trifolium Prototype