Teacher Information:

 The problem presented here is an interesting one that will really tax the students' creative potential. The students will have to build a robotic arm that will have to move left to right a distance of one meter, up and down a distance of one half meter, and pick up and carry a ping-pong ball while it does this moving.

This problem may seem like a brick wall to some, or all, of the students when first presented. But in reality it is very simple.

The first concept to look at is the human arm, how does it work, what powers it, what allows the movement in different angles? In the class brain storming session the working aspects of the human arm can be explored and analysed. A good activity is to have a P.E. teacher, or some one well versed in the mechanics of the human body, to come in and discuss with the students how the human arm works.

The second concept to look at is the function of the human hand. At this point many students might possibly get hung up on thinking that they must build a replica of the human hand; not so. Look at other methods of picking up the ping-pong ball. Remember to lead the discussion, do not present alternatives. Several alternatives to the hand would be; a vacuum pick up, sticky pickup or scoop pick up. The ways of solving the problem are as diverse as the number of students.

Students may also think that the arm must be very high tech in its construction and operation. A simple multi section arm constructed out of thin pieces of wood and operated by pull strings for movement, and sucking on a small diameter hose for the ball pick up works very well. The tendency for students to make this and any project too difficult is great. Direct the groups and teams towards the simple but effective approach to solving the problem.

There are books in most school libraries, or public libraries, which discuss the concepts and construction of simple home made robots. These books, if kept in the class room, can be a good source of background information for the students.

Marking of the project will follow the same method as for the previous projects: one hundred for the project and one hundred for the student evaluation. The guide-lines, or construction performance parameters, are set out in the following manner:

Performance and Construction Guidelines 

A) The base of the arm must be fixed and not able to move.

B) The arm must be able to move side to side a minimum of 90 degrees.

C) The arm must be able to reach outward one meter from the starting point.

D) The pick up end of the arm must be able to lift up at least 600 cm.

E) The arm must have an elbow to allow movement of the pickup from a starting point 200 cm from the    base outward one meter.

F) The students hands may not touch the arm while testing, it must be remote controlled.

G) Both team members may operate the arm at one time.

 Marking

A) Movements: if meets all movement guideline 20 marks
B) Pick up and Carry the balls:  

Four tries worth 5 marks each for a total of 20.
Drop the ball lose 5 marks.
Damage the ball lose 2 marks.

C) Time: Four tries worth 5 marks each for a total of 20 marks.

   Students have 30 seconds to go from rest point (200 cm), pick up the ball clear obstacle, deposit ball    return to rest point.
   Lose two marks for every 5 sec. slow.
   Gain two marks for every 5 seconds faster than 30 seconds.

D) Placement Accuracy: Four tries worth 5 marks each for a total of 20 marks

5 marks ....... first try
4 marks ....... second try
3 marks ....... third try
2 marks ....... fourth try
1 mark ......... fifth try

E) Construction: Teachers evaluation of students project = 20 marks.

F) Teacher evaluation of student =100 marks

 TOTAL for project = 200 Marks.

Student Lab

Name: __________________
Partner: _________________  

 The Problem

Design and build a robotic arm that will be able to carefully pick up a ping-pong ball from a small stand, move it in a clock-wise direction while clearing a 500 cm. high obstacle, and deposit it on another small stand one meter away.

You will be free to use any kind of material that you feel meets your design requirements and is readily available to you. Scrounge what you can from home, buy what you may need and use items from the shop, as long as they are returned when the project is finished.

Below are the design parameters that you must follow, and will be marked on.

Design Parameters

A) The base of the arm must be fixed and not able to move.

B) The arm must be able to move side to side a minimum of 180 degrees.

C) The arm must be able to reach outward one meter from the starting point.

D) The pick up end of the arm must be able to lift up at least 600 cm.

E) The arm must have an elbow to allow movement of the pickup from a starting point 200 cm from the base outward one meter.

F) The student's hands may not touch the arm while testing; it must be remote controlled.

G) Both team members may operate the arm at one time.

  Marking

A) Movements: if meets all movement guideline 20 marks
B) Pick up and Carry the balls:  

Four tries worth 5 marks each for a total of 20.
Drop the ball lose 5 marks.
Damage the ball lose 2 marks.

C) Time: Four tries worth 5 marks each for a total of 20 marks.

   Students have 30 seconds to go from rest point (200 cm), pick up the ball clear obstacle, deposit ball    return to rest point.
   Lose two marks for every 5 sec. slow.
   Gain two marks for every 5 seconds faster than 30 seconds.

D) Placement Accuracy: Four tries worth 5 marks each for a total of 20 marks

5 marks ....... first try
4 marks ....... second try
3 marks ....... third try
2 marks ....... fourth try
1 mark ......... fifth try

E) Construction: Teachers evaluation of students project = 20 marks.

F) Teacher evaluation of student =100 marks

 TOTAL for project = 200 Marks.

How many ways can you think of to power the arm? The easiest will be the most simple and the most effective. It would be nice to have a computer control it, but even electricity can be a problem to hook up and control. Again, THINK, use your imagination

 Below is a bird's eye view of the distance from A to B that the arm must move, and the distance the pick up must move from 200 cm out to the one meter mark. The arm must pick up the ball where line A crosses the one meter mark, and deposit it where B crosses the one meter mark.

 

Above is an example of a very basic arm system. Yours must be of a similar design in terms of having a base, a pivot and an elbow which will allow the pick-up to reach back towards the base to the starting point. Do not get mind set in thinking that you must have a hand to pick up the ball, there are lots of different ways to do it. USE YOUR IMAGINATION!!