Entries by Prof. McCarthy

How to Fix SW Motion Analysis Error: Too Many Redundant Constraints

Kevin Chen,  J. Michael McCarthy,  Shaun Bentley The design and assembly of our four-legged mechanical walkers can yield single degree-of-freedom systems with so many redundant mates that it stalls SolidWorks’ Motion Analysis.  For example, the walker shown in Figure 1 had 782 redundant mates.   The procedure outlined below reduced the number of redundant mates […]

The Design of Mechanical Walkers: Spring 2020 Student Projects

While isolated to slow infections of the Coronavirus, over 60 UCI students learned how to apply the principles of Curvature Theory and Finite-Position Synthesis to the design leg mechanisms for mechanical walkers. Their first team project was a four-legged walker that used the coupler curve of a four-bar linkage positioned using a skew-pantograph as the […]

Construction of a Leg Mechanism

This is a series of four videos that show how to: Specify three positions for the foot of a leg consisting of a hip and knee joint; Use three position synthesis to design a four-bar function generator to guide the hip joint; Then use three position synthesis to design a second four-bar function generator to […]

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 […]

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 […]