Internal Geneva Mechanism
Aim: MultiBody Dynamics using Solidworks.
Theory: Geneva mechanism, also called Geneva Stop, one of the most commonly used devices for producing intermittent rotary motion, characterized by alternate periods of motion and rest with no reversal in direction. It is also used for indexing (i.e., rotating a shaft through a prescribed angle).
Contact Force: A contact force is any force that requires contact to occur.Contact forces are ubiquitous and are responsible for most visible interactions between macroscopic collections of matter. Pushing a car up a hill or kicking a ball or pushing a desk across a room are some of the everyday examples where contact forces are at work.
Angular Displacement: Angular displacement of a body is the angle in radians (degrees, revolutions) through which a point revolves around a centre or line has been rotated in a specified sense about a specified axis. When a body rotates about its axis, the motion cannot simply be analyzed as a particle, as in circular motion it undergoes a changing velocity and acceleration at any time (t). When dealing with the rotation of a body, it becomes simpler to consider the body itself rigid. A body is generally considered rigid when the separations between all the particles remain constant throughout the body's motion, so for example parts of its mass are not flying off. In a realistic sense, all things can be deformable, however, this impact is minimal and negligible. Thus the rotation of a rigid body over a fixed axis is referred to as rotational motion.
Model:
1. Geometry of Driver wheel
2. Geometry of Driven wheel
Procedure:
1. First we will draw the CAD model of driver and driven wheel in solidworks using the required dimension.
2. Then, We will assemble the two parts in solidworks assembly so that we can do motion analysis of the model.
3. Now, We will go to part modelling of the driver part and we will measure the distance of the axis of the two parts using the measure tool.
4. Now we will use solidworks motion to define the contact group between driver and driven model.
5. Now, We will make the driver part as the motor and specify its rpm as 10 and then 20.
6. Now we will calculate and then we will go for results and plots to do post processing.
Precise Contact:
At 10rpm
At 20rpm
Results and Plots:
Contact Force at 10 rpm
Angular Displacement at 10rpm
Angular Velocity at 10rpm
Contact Force at 20rpm
Angular Displacement at 20rpm
Animation Video of Geneva Mechanism at 10rpm
Animation Video of Geneva Mechanism at 20rpm
Results:
The Angular displacement plot shows a linear trend.
The number of peaks increased linearly.
For 10rpm, the Angular velocity is steady with time