Mechanism Synthesis

1
Mechanism Synthesis

• W. Farrow

2
Qualitative Synthesis

• Creation of potential solutions in absence of
  well-defined algorithm

• Fuzzy generation of potential solutions

• Creative design and past experience

3
Type Synthesis

• Definition of proper type of mechanism best
  suited
• Solution driven by many variables including cost.
• An exercise in tradeoffs.
• What kind of mechanism should it be?

4
Dimensional Synthesis

• Determination of link proportions necessary to
  accomplish goals
• Usually requires a combination of qualitative and
  quantitative synthesis.

5
Mechanism Goals

• Function Generation
• Path Generation
• Motion Generation

6
Function Generation

• Correlation of an input motion with and output
  motion
• y f(x)
• x motion of input member
• y motion of output member

7
Path Generation

• Control of a point such that it follows a
  prescribed path
• Usually employs knowledge of coupler-point curves

8
Motion Generation

• Control of a line such that it assumes a
  prescribed set of sequential positions.

9
Limiting Conditions

• Limitations in the motion of the a mechanism
• Maybe a design
• Advantage
• Disadvantage
• Requires analysis of mechanism after dimensional
  synthesis to identify limitations.

10
Toggle Positions

• Occurs when two moving links become colinear.

11
Transmission Angle

• Angle between output link and coupler
• Optimum 90º Minimum 40º