Showing posts with label Mini project. Show all posts
Showing posts with label Mini project. Show all posts

Report on Geneva Mechanism | Mini Project

The Geneva wheel or Maltese cross is a cam like mechanism that provides intermittent rotary motion and is widely used in both low and high speed applications. Geneva mechanism is extensively used in automatic machinery where turret, spindle or worktable must be indexed. Geneva mechanism is popular from longer times by means of producing positive incremental motion.

Construction :

The basic structure of 4 slot geneva mechanism is shown in figure below.

The system consist of constantly rotating disk coupled with a slotted disk, which gives rise to the desire discrete motion. 
A rotation of 2p radians of the former cause 2p/N radians of rotation of the latter, where N is the number of slots available on the slotted disk.
Thus, one complete rotation of the slotted wheel requires N complete rotations of the other disk, thereby also increasing the time period.

Working :

Refer the figure above. Pinwheel W rotates constantly about axis A and has a pin 'a' attached to it. This pin 'a' engages into the slots 's' of the geneva  wheel 'G' and rotates it as long as it is engaged with the slot. While the wheel rotates continuously, the Geneva wheel has a discrete rotation about axis 'b'. 
Wheel 'G' has a rotation time period of 'tr' when it is moving with disk 'W' and an idling time period of 'ti', when the pin 'a' is not inside one of the slots 's' and is moving freely. 
The three quarter wheel 'L' is placed in order to prevent any unintentional rotation of wheel 'G' while it is idling. 

Mini Project on Robotic Gripper Mechanism

Gripper is a mechanical device which enables us to hold an object to be manipulated. Gripper can be described in much more easier way by thinking its a human hand. Just like fingers of hand, gripper enables us to hold, tighten, release and handle an object. A gripper can be a part of fixed automation system or it may be attached to the robot for performing specific operations.
There are a variety of grippers available in industry.

Operating Principle of Gripper

The opening and closing of fingers of gripper can be actuated either by pivoting or linear/translational movement.
Pivoting Movement : In this movement, the rotation of fingers is concerned with the pivoted points that are fixed for providing opening and closing action. To achieve this movement, it uses linkage mechanism.
Linear/Translational Movement : In this movement, the gripper jaw moves parallel to the gripper body. These grippers are used in most of the applications. These type of grippers are more accurate than other types of grippers.
Mini Project on Robotic Gripper Mechanism |
Linkage Actuation

Linkage Actuation

The design of linkage actuation helps to find out the conversion of the mechanical gripper's force into the gripping force and the time taken by them to actuate the gripper and maximum capability to open the finger.
There are number of designs available for linkage actuation, some of them are shown in above figure.

Now moving towards the video, we will see how the gripper works. Here we will see, few mechanisms of robotic gripper and their models.

Type 1 gripper :

A cylinder (it can be either hydraulic or pneumatic) attached to the slider (shown in pink color) causes the opening and closing of the gripper and hence permitting it to grasp and release the object.
The slider is connected to the links (shown in yellow color) which forms a slider crank mechanism and thus, is responsible for actuation.

Type 2 gripper :

 In this mechanism, one end of piston of cylinder is attached to rack or say any tooth like mechanical element. This element engages in respective meshing element (here pinion) which is pivoted at one point. As the cylinder actuated, the gripper open and closes as per the motion of the piston. Thus, it creates a parallelogram mechanism.

Type 3 gripper :

In this type of mechanism, a bar is directly connected to the piston of the cylinder responsible for the opening and closing of the gripper.
It is also an example of slider crank mechanism.

Type 4 gripper :

   It is quiet similar to the type 3 gripper. Only the change is in design of mechanism.

Mini Project on Conversion of two way linear motion into one way rotation

Hello friends, we are back again with one more mini project. We hope you have gone through all previous mini projects,seminars and projects.
Moving towards the subject, in this post we are going to show you how linear motion is being converted into rotational motion. Basically, for conversion of linear motion into rotational motion different types of linkages/mechanisms are used and rack & pinion is one of the famous mechanism used for such conversions.
Mini Project on Conversion of two way linear motion into one way rotation |
Mini Project on Conversion of two way linear motion into one way rotation
The mechanism consist of two rack gears fixed at two ends and a pinion pair engaged in the tooth of both rack. There is also a gear pair having buttress threads on it and their corresponding rollers which restricts backward motion. All the gears i.e. spur gears and buttress tooth gears are mounted on same shaft.
When the rack moves forward or backward, its linear motion is converted into rotary motion by pinion. This rotary motion of pinion is transferred to further mechanism through shaft on which it has been mounted.
Here you have to note one thing that, rack and pinion gear only converts linear motion into rotary motion, and it does not reduce the speed as its gear ratio is always 1.
Have a look at the video, how Conversion of two way linear motion into one way rotation works.

6 Ways to Finish Your Projects

We can work on many projects at a time. There is no doubt that finishing the project gives all of us a great pleasure. But at the time of finishing the project, it takes some practice at the skill of finishing stuff.

Start of Project |

It is said that the last 10% of the project is the 90% of the work. It means that first 90% of the project is only the visualization which is of only 10% of work.
Have anyone ever thought that why finishing the projects is so tough than to start them ?
Starting is much easy which involves option for researching, discussion and much more. These tasks gives us pleasure that we have completed something. Making something out of nothing, to design something or to build something where it wasn't in existence before is HARD. If you are not feeling any sense of accomplishment, you cannot know how much you are missing to want to feel it badly.
I think finishing the projects is a learned skill that provides you an experience about how much long some things can take.Obtaining the skills of Finishing Stuff takes practice.
Here are those skills that you should practice to gain them for Finishing the projects.

1. Make decision to stop being an anal perfectionist.

 You can lose a ridiculous amount of time going from red to blue and back again. Tweaking this and tweaking that keeps you in the 50% done phase which is essential. It also tricks you out of having to think too hard about solving the problem.

2. Don't add tentacles to your Revision 1 project.

Unnecessarily adding tentacles to your project will make them unwieldy and unmanageable, which may cause the project to sit tin the garage.

3. Kill your wireless and put caution type across your kitchen door (No Distraction)

How can you get anything done if internet life is blinking at you ?
Leaving your Facebook, emails, twitter, etc on while you are trying to move forward is just a bad decision. It takes an average person some time to get their brain back on the track after an interruption, and you are no exception.
And don't iterrupt yourself because you are hungry or need to do dishes. Finding oneself in the kitchen staring into white light is also not productive.

4.Practice working your way through problems.

Keep in mind that, you can't heat the wall of problems and delay them or ignore them. When you get to a stopping place because you don't know what to do, do something. If you don't know what to do, ask someone, get the help from someone, ask forum, ask Google, and experiment. Do no hesitate to ask queries to anyone, just ask them.

5. Set a deadline that is 2 weeks from now.

When you have a deadline that is too far away, it is easy to wait until the last minute. Then after that you have no time and the project doesn't get completed. Break the project up into 2 week doable sized pieces.

6. Keep it simple....... soooo simple.

Dont pick much more projects (say 10 projects) that are not doable. Pick something challenging you know you can do and tackle it. Don't wake a day and decide to build a small shed on your property... alone... and find that you dont have the time, money, skill set to finish it. know yourself better than that.
End of Project |

The way to get good at something, good enough, is to do it over again and again until you have mastered that skill. If you finish a few projects, there are the chances that you will never want to leave the work undone.