Materials

Materials needed:
4x wooden rods to support each ends of the arms
8x screws
2x nuts
2x sensors
2x servo motor-continuous
Polycarbonate plate 200x300x4.6

*The drawing is not drawn to scale

The left and right claw are almost the same except for one part.

The dimensions of the drawings have not been decided yet but this is what the mechanism is supposed to look like.

Isometric drawing

This is the detailed 3D drawing of the mechanism. The claws will be attached in front of the base chassis. Its function is to grab the can and move backwards to the starting line while pulling the can along with it.

More modifications will be added to the design later on.

Delay

Sketching of the mechanism is done and will be posted on the blog on Monday(21/6/10)as there will a group meeting. The mechanism has been confirmed. The mechanism will be broken down into several components. The length and width estimated will be recorded and done in AutoCad 2010.

Furthermore information will be posted next week after the group meeting.

The fabrication of mechanism and programming will be done on week 11.

Brainstorming and generating concepts

Task 1:Brainstorm and generate concepts of a mechanism to fulfill the function of transporting an empty drink can across a given distance of 50cm.

Conditions:
-During the time span of 2mins, the robot is supposed to travel 50cm of distance to carry or toss the (70mm in diameter) can back to the starting line.

-The design of the robot can only fit into a perimeter of maximum 400x300x300 mm including the operating locus of any mechanism.

-No modifications to the Base chassis.

Decisions:
Toss or transport.

Toss
Pros and Cons
-Pros
It is more efficient to toss the can back to the starting line as the robot can transport more cans within the 2mins time limit. There is no rule saying that the robot must be at the starting line after transporting the can.
-Cons
However, creating the mechanism is not easy and the motor might not have enough power to toss the can back to the starting line. Using gears can help to increase the power of the motor but it will also reduce the speed. Thus, the robot might not be able to transport as much cans back to the starting line as expected.

Carry
Pros and Cons
-Pros
Building the mechanism would not be difficult as it will only involve grabbing of the can.
-Cons
It would be more time consuming as the robot have to return back to the starting line. There is also a rule stating that no modification to the base chassis is allowed thus gears could not be added to increase the speed.

Ideas:
1) Building a slide and a grabber.

How it works:
This mechanism is using the toss idea. Instead of tossing, the can would be rolled back to the starting line like on a slide. Firstly, the can would be pushed onto the slide by tiny grabbers at the side of it. Then the slide would flip backwards which will carry the can along with it. Then by gravity, the can would slide down and roll towards the starting line.

Pros
The robot does not have to move back and forth. As it is a slide, little power is needed to bring the can back to the starting line.

Cons
A lot of power is needed to flip the slide backwards as it is now carrying the can. A lot of materials would be needed to build the mechanism and it might exceed the materials given. Fabrication of the mechanism would be tough especially the tiny grabbers. Not to forget that a sensor has to be addded in.

2)Grabbing the can and move backwards

How it works:
The concept is simple. The robot will grab the can using claws inserted in. Then instead of turning 180 degrees, it simply moves backwards. When it reaches the starting line, it lets go of the can.

Pros
The mechanism is easy to construct and a sensor can be inserted in easily. It is more efficient to just move backwards instead of turning 180 degrees back and returning to the starting line.

Cons
It is much slower than tossing and it requires mobility as the robot has to return to the starting line and go back. Furthermore, there is a rule saying no modification to the base chassis so modification to the robot's speed is not applicable.

Our group has only narrowed down to these two ideas as it appeared to be reasonable and applicable. The rest of the ideas are not constructable as we are not sure on how to construct it.

After the group's discussion over the last two weeks, we had decided to go with decision no.2 as it is much easier to construct and seen as the most promising.