Mechanisms and Robots: Geometry in Motion Prof. Venkat N. Krovi

GMP Seminar 

Venkat Krovi 

Mechanisms and Robots: Geometry in Motion 



Venkat N. Krovi 

Associate Professor 

Mechanical and Aerospace Engineering 

University at Buffalo (SUNY) 

Buffalo, NY 

vkrovi@eng.buffalo.edu 

University at Buffalo 

The State University of New York 

http://mechatronics.eng.buffalo.edu 

Research Interests 

t 

Research Highlights 

ht 

Honors 

Prof. Venkat N. Krovi 

1012 Furnas Hall, North Campus 

Phone: 716.645.1430 

E-mail: vkrovi@eng.buffalo.edu 

WWW: http://mechatronics.eng.buffalo.edu/ 

• Lifecycle treatment 

(design, analysis, 

implementation 

and verification) of 

smart, mechanical and 

mechatronic systems. 

• Research Thrusts 

(a) Multi-robot Cooperative 

Payload Transport 

(b) Haptic Device Design 

(c) Mediated Teleoperation; 

(d) Haptic Rehabilitation 

(e) Distributed real-time 

simulation/control of systems. 

• NSF CAREER 2004 

• 2000 Petro-Canada Young 

Innovator, McGill University 

Professional Activities 

• ASME DSCD Robotics TC 

(Founding Chair) 

• TE, IEEE/ASME Transactions on 

Mechatronics 

• AE, ASME Journal of Dynamic 

Systems and Control, AE 

• Program Chair, M&R Conference 

2010, IDETC 2010 

• Finance Chair, CASE 2010 

• Finance Chair, ICRA 2010 






What are “Mechatronic/Smart 

Systems”? 

Computer-integrated, network-enabled electromechanical 

systems capable of working with virtual/real environments, 

human users and other smart systems, to enhance 

performance and productivity 

E.g. Cell Phones to Mars Rovers 

Theme: Modulation of power within articulated multibody systems 

Smart Car Haptic Telerehabilitation Musculoskeletal Analyses 

Virtual 

World 

Real 

World 

Human User 

Smart System 

Microcomputer 

Network 

Sensors 

Actuators 

Smart System 

Microcomputer 

Network 

Sensors 

Actuators 

Multi-loop Articulated 

Mechanical System 

Acknowledgements 

• Bhatt, Rajan 

• delSignore, Michael 

• Fu, Qiushi 

• Jadhav, Chetan 

• Jun, Seung-kook 

• Kannan, Srikanth 

• Lee, Lengfeng 

Army of Ants 

NSF CAREER IIS-0347653 

Design, modeling, analysis, simulation & prototyping of 

“Mechatronic & Robotic Systems” 



Associate Professor 

Mechanical and Aerospace Engineering 

Uneven Terrain Locomotion 

Acknowledgements 

• M S Narayanan 

• Miller, Patrick 

• Naik, Anand 

• Nair, Pravin 

• Tang, Chin-Pei 

• White, Glenn



Cooperative Payload Transport by 

Robot Collectives: An Army of Ants 



Uneven Terrain Locomotion 

Initial 

Position 

Initial Position 

Virtual Prototyping 

Verification by Co-simulation 

Physical Prototyping 

Verification by Hardware-in-the-loop Testing 

Original Design 

Wheel Paths of the Different Designs 

The modified design is better suited to 

absorbing disturbances due to the obstacles 

by moving up and away from the obstacle 

Modified Design 

Modified Design 

NSF CAREER IIS-0347653 



Computational Musculoskeletal Modeling 

and Analysis 



CENTRAL INTERFACE 

So what does this have to do with 

today’s talk? 

Machines and Robots Embody “Geometry in Motion” 

The fundamental concepts of 

modeling, design and analysis 

of 

mechanisms and machines 

forms the basis of the research activities. 

i th t i l ki ti d d i d li 

i.e. the geometrical, kinematic, and dynamic modeling 

and analysis of articulated multibody systems



Mechanisms and Machines 



Tasks of Interest: 

Manipulation of Motions and Forces 

As Mechanical Engineers we are interested in: 

Modulation of MOTIONS, FORCES (and POWER) 

Simple Motions and Forces: 

We use “simple” machines!! 

These devices were all in common use from prehistoric times. 

THINK: Egyptian, Inca, Greek and Roman Empires 

Each one makes work easier to do by providing some trade-off between the 

force applied and the distance over which the force is applied. 



http://www.fi.edu/qa97/spotlight3/spotlight3.html 



Modulation of Motions and Forces 

As Mechanical Engineers we are interested in: 

Modulation of MOTIONS, FORCES (and POWER) 

What do we do when we need to provide 

complex motions and forces? 

Complex Motions and Forces ?? 

Y 

Quoting Archimedes in the Doric speech of Syracuse : "Give me a 

place to stand and with a lever I will move the whole world." 

Z 

X 

Useful Engineering Practice 

Compositional Approach



Articulated Linkages 

• Multiple articulations are required in order to trace more complex curves 

• Increases the degrees-of-freedom 

• Constraints need to be created – Why ??? 

Passive “Hardware” Constraints 

(Four-bar) 

Active “Software” Constraints 

(Robot) 



Think-Pair-Share 

• Question: 

Where do YOU see applications for 

what you will learn in Mechanisms and 

Machines in your “day-to-day lives”??? 

-- Which “products” ??? 

-- Which “industries” ??? 

Single actuator 

Three actuators 





Flowing 

water/wind 

Acted as a 

Power source 

Various other 

mechanisms 

to convert this 

to other types 

of motions & 

forces 

Middle Ages 

-- Chinese Locks 

-- Church Organs 

Design of 

Machines was an 

“art” – you served 

an apprenticeship 

to become a 

renown expert 

Mid-1800s Industrial Revolution 

Created a greater need for mechanisms 

Mid-1800s Industrial Revolution created a need for new mechanisms 

Watt’s governor – to control speed of “automatic machinery” 

Straight line mechanism – long stroke for engines 

Jacquard looms – automatic looms



MODERN DAY MECHANISMS & MACHINES 

Venkat Krovi Venkat Krovi 

Cherokee Engine 

Front End Loader 

L-1011 Landing Gear 

Intermittent Contact 

Cam 





A note on “creativity” 

How do we create mechanisms to do a particular job ?? 

• Eureka !!! 

Segue: So How Does One Design 

Machines and Robots Anyway? 

• Recipebook 

– Typically many “sourcebooks/cookbooks”of 

candidate 

simple/complex l mechanisms 

– Mechanisms and Mechanical Devices 

Sourcebook 

Neil Sclater, Nicholas P. Chironis 

ISBN: 0071361693 

• Constructionist Approach 

– Combine many simple machines to 

create a complex machine 

– May not be the most efficient but often 

tends to be simple to analyze







How do we create mechanisms to do a particular job ?? 

Pencil Sharpener 

• Then comes the problem of adapting it 

for your own task at hand 

– This is what we would like to address 

in a systematic “analytic” manner 

How do we create 

mechanisms to do a 

particular job ?? 

http://www.rubegoldberg.com 

Rube Goldberg Commercial 

How to build a Rube Goldberg machine 



Evolution of Mechanism Analysis 



Ideal Mix 

– Graphical Tools 

• First used – promotes visual 

understanding 

• Kinematics is “geometry in 

motion” 

– Analytical l Tools 

• Uses Algebra and 

Trigonometry 

• Permits computer 

manipulation of data 

Link Traditional Approach and VP Approach 

Link 

– Computer-based tools 

• Fast implementation 

• Repetitive stuff becomes 

easy 

• Can be augmented by 

visualization 

• Includes both: 

– Use of current 

Technological Tools 

– Learn to develop tools for 

the future 

Traditional Approach 

Grashof 

Non-Grashof 

VP Approach



Try it out for yourselves!!! 




Web-Based Self-Paced Tutorials 

A web-based tutorial 

developed, eloped permitting 

students to: 

• interactively explore 

the process of 

creating 

engineering 

analysis models in 

integrated VP 

environment; 

• develop skills for 

interactive e SBD of 

models; and 

• develop 

engineering 

judgment by 

interactive 

exploration of a 

spectrum of 

exercises. 

http://www.eng.buffalo.edu/Courses/MAE412/tutorials/index.html 

Web-Based Self-Paced Tutorials 

http://mechatronics.eng.buffalo.edu/education/NewfaneHighSchool 






http://www.rubegoldberg.com 

Rube Goldberg Commercial 

How to build a Rube Goldberg machine 

Questions? 

http://www.wonderhowto.com/how-to-build-rube-goldberg-machine-kids-204880/

Mechanisms and Robots: Geometry in Motion Prof. Venkat N. Krovi

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