These notes introduce students to research on classifying linkage systems which involves a variety of ideas such as Assur groups, Baranov trusses, and Rigidity theory. Organizing the increasing complexity of machine systems to guide inventors has attracted researchers for literally generations and has generally been called “Type synthesis.” The goal is to provide a systematic way to explore the types of linkage systems that are available to address a design need.Type Synthesis
Lecture notes on specific topics.
Nicholas Bodley sent me to www.maritime.org for information about the MK.1 mechanical computer that he used as a Navy Fire Control Technician during the Korean War. Just the schematic of its operation is a dizzying flowchart.
A description of the mechanical components of this computer system can be found in the manual Basic Fire Control Mechanisms (62.7MB). It is an excellent description of the use gears, cams and linkages for computation.
Select this link, Four-bar linkages, for a Geogebra book that illustrates linkages ranging from a lever to a crank-rocker that open a door. This includes the construction of a four-bar linkage that coordinates the open and closed positions with specific input crank angles, called a four-bar function generator. The iPad application, MechGen FG, computes four-bar function generators for five coordinated values of the input and output cranks.
Profs. Carl Nelson and Anurag Purwar organized a Summer School on Kinematic Theory at the University at Buffalo, New York as part of the 2014 ASME Design Engineering Technical Conferences. Please select this link to get access to all of the talks: Kinematics Summer School.
My lecture on the synthesis of six-bar and eight-bar linkages is the third item on the playlist.
You can access a pdf of my talk at the link: Synthesis of Planar Six-bar and Eight-bar Linkages.
Among these is a nice presentation by Anurag Purwar on Quaternions and Clifford Algebras.
Please select this link to open the Geogebra Book containing constructions of a number of interesting linkages. This is an introduction to the useful movement available with articulated systems.
This video from the University of Dayton narrated by Prof. Andrew Murray provides an excellent illustration of the important concept of mechanical advantage.
Select this link to download a .pdf version of A. Svoboda, Computing Mechanisms and Linkages, Dover Publications, 1965, (17MB). This book was originally published by McGraw-Hill in 1948.
Select this link to download a .pdf version of A. B. Kempe, How to Draw a Straight Line, MacMillan and Co., London, 1877. (1.8MB)
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.
- Computer-Aided Invention of Mechanisms and Robots. J. Michael McCarthy, Professor, University of California, Irvine.
- Mechanism Synthesis for Modeling Human Movement. Vincenzo Parenti-Castelli, Professor, University of Bologna.
- Algebraic Geometry and Kinematic Synthesis. Manfred Husty, Professor, University of Innsbruck.
- Kinematic Synthesis of Compliant Mechanisms. Larry Howell, Professor, Brigham Young University.
- Kinematics and Numerical Algebraic Geometry. Charles Wampler, Technical Fellow, General Motors Research and Development.
- Kinematic Analysis of Cable Robotic Systems. Vijay Kumar, Professor, University of Pennsylvania.
- Protein Kinematics. Kazem Kazerounian, Professor, University of Connecticut.
Colleagues joined in with two additional presentations:
- Development of Fast Pick and Place Robots. Jorge Angeles, Professor, McGill University.
- Kinestatic Analysis of Mechanisms with Compliant Elements. Carl Crane, Professor, University of Florida.
Many thanks to the contributors and the attendees for an outstanding workshop.
Recently, I became aware of the overall poor quality of the articles on machines in Wikipedia, and I have spent quite a bit of time revising these articles over the past month. I hope my contributions are an improvement. Please take a look:
- Machine (mechanical)
- Mechanical system
- Linkage (mechanical)
- Screw axis
- Burmester’s theory
- Four-bar linkage
- Mechanism (engineering)
- Instantaneous center of rotation
- Screw theory
- Dual quaternion
- Mechanical advantage
- Overconstrained mechanism
- Kinematic pair
- Virtual work
As you may know anyone may edit Wikipedia, and it is intended to allow user communities to maintain the quality of particular sets articles. It is important that we take this opportunity because Wikipedia is an important resource to our students.