## LINCAGES and the History of Kinematic Synthesis

The linkage design software developed by Art Erdman and his students at the University of Minnesota, called LINCAGES: Linkage INteractive Computer Analysis and Graphically Enhanced Synthesis Package, was developed in 1977 through 2000. This is a link to his information site. His guide map that evaluates all of the linkages formed from points on the circle-point and counter-point curves was a nice innovation.

This link connects to a YouTube video shows the linkage design process using LINCAGES:

https://youtu.be/ZuC-D8EQeNM

## Strider and TrotBot at DIYWalkers.com

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 DIYWalkers.com

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.

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

## About Geogebra-Kinematic Synthesis of Mechanisms

The animated four-bar linkage FHJD is constructed using dimensions as the quadrilateral ABCD. The dynamic geometry software Geogebra maintains the dimensions of FHJD as the points of ABCD are moved. The result is that the animated linkage changes to match the new dimensions. This can be seen in following Movie.  For more information see Kinematic Synthesis of Mechanisms.

## Chapter 6 Animations-Kinematic Synthesis of Mechanisms

Here are the eight Movies in Chapter 6 of Kinematic Synthesis of Mechanisms.

## Chapter 5 Animations-Kinematic Synthesis of Mechanisms

Here are the four Movies in Chapter 5 of Kinematic Synthesis of Mechanisms.

## Chapter 4 Animations-Kinematic Synthesis of Mechanisms

Here are the four Movies in Chapter 4 of Kinematic Synthesis of Mechanisms.

## Chapter 3 Animations-Kinematic Synthesis of Mechanisms

Here are the four Movies in Chapter 3 of Kinematic Synthesis of Mechanisms.

## Chapter 2 Animations-Kinematic Synthesis of Mechanisms

Here are the six Movies in Chapter 2 of Kinematic Synthesis of Mechanisms.

## Chapter 1 Animations-Kinematic Synthesis of Mechanisms

Here are the three Movies in Chapter 1 of Kinematic Synthesis of Mechanisms.

## Kinematic Synthesis of Mechanisms: A project based approach

This book is an introduction to the geometric theory used to design linkage systems that are critical components of machines ranging from vehicle suspensions to robot arms. The focus throughout is on graphical synthesis of linkages to control the movement of the legs for a walking machine.

Select this link to see the Kindle Interactive version in Amazon

Select to see this book in Apple Books

Increasingly complicated walking machines obtained from patent drawings, art and technology are used to motivate the theory. Starting with legs formed by rotating cranks, we move to legs constructed from four bar linkages with specially shaped coupler curves. This leads to a search for coupler points that have near straight line trajectories, and motivates constructions for the inflection circle and cubic of stationary curvature. We also consider cognate linkages and those with symmetric coupler curves.

The use of an RR chain controlled by the coupler of a four-bar linkage is our introduction to six-bar linkages. Then skew pantographs that provide scaling and reorientation of a coupler curve for better walking movement yields eight-bar linkages. The legs designed by Theo Jensen and Amanda Gassaei are shown to implement four bar function generators that control the joint movement of an RR chain. This leads to graphical two and three position synthesis of four-bar function generators, which are applied to the design of legs with two and three specified configurations.

We end with a description of the duty factor and support pattern needed for two, four and six legged walking machines. The challenge of steering and suspension is left for the future.