Q&A:
Question: Problem with clear tubing over the stiff copper joint that connects foot motor to leg
Question: We’ve had some problems soldering. Do you have any suggestions?
Question: I have gone through a lot of batteries to test to walk our robot...
Question: Can we change our team name? What do the hurdles look like?
Question: Any suggestions on the Written Report and Walking the Robot.
Question: My robot keeps falling over. What can I do about it?
Question: The legs of my robot keep getting jammed. What can I do about it?
Question: How to we get our robot to walk consistently and reliably?
Question: We are ready and prepared for the competition. Our robot now does not jam...
Question: How are the points for this competition actually broken down?
Question: Is a stiff flag made from a hard material like poster board or wood?
Question: Where do we find the team number?
Question: Is there a weight requirement for the robot?
Question: How do I enhance traction of the robot?
Question: Do the rules specify if the motors have to be covered by the robot costume.
Question: The threads are damaged or worn out in items #3 and #4, threaded rod slipping in custom arm
Question: The color of the wires in the kit don't match the instructions in the manual
Question: Advice about wiring the power unit to the control unit
Question: What is the purpose of the shallow channel (indent) on the side of the wooden body?
Question: What is the angle that they use to drill the holes in the wood block.
Question: When do we register the names of the students in the groups for the competition? Also, who should we be sending this information to?
Question: School did not do so well last year with the presentation portion of the challenge. We wanted to see if there was a rubric that is used for this area. Also, we wanted to see what the general format of the presentation is – should they be talking about their construction and testing process? Or, should they just be prepared to answer questions? We want to make sure that the students do better in this area.
Question: Regarding the written portion of the challenge – were the students supposed to outline their process or were there specific sections that needed to be included into the report?
Suggestions:
1. Remember to have a shipping container for the robot body. This is
important for two reasons: It will protect the robot legs from getting bent
on the way to the Museum. If they get bent it will increase the vibration, it
will slow the robot down, and it may fracture the white plastic L-shaped
part. The second reason is that it could give you 2 extra points during the
Oral Presentation. At the very least use a 12 bottle wine carton, and lay the
robot on the top of the dividers, so that the legs are in the gaps and free
from stress. Or you can make up a box from styrofoam or anything else.
2. You are required to have a flag with your team number, and if you
wish, your team logo. The manual, on page 16b. states: You will need to make
and take with you to the competition, a 1/4 to 1 inch diameter floor-mounted
flagpole 56 inches high, with a square or triangular stiff flag 6 inch high
by 8 to 10 inches wide. The flag should have your team number clearly visible
both sides, and may also include a team logo.
3. Please practice, and remember that while luck plays a part in the
competition, attention to details is what will give you the edge.
4. Especially for 2-leg robots, good traction is what will lead to steady
progress on the track. Put a glob of rubber cement at the bottom of the
rubber pad, let it dry for an hour, and you’ll find it provides better
traction. You might want to add a little more the morning of the competition.
Directions
5. To get to the Baltimore Museum of Industry, 1415 Key Highway, you have
2 options: (click here for Map)
1. Go down to the Baltimore Inner Harbor and look for Light Street, which is
at the Eastern end of the water. South on Light St., past the Science Center,
to Key Highway, turn left. Follow Key Highway as it winds along the docks
till you see a huge crane which is located in the grounds of the Museum. Take
the next driveway on your left, and park.
*There is a large brick building near the entrance (the Administration Bu
ilding) and the Museum is to your left.
- On Saturday, the Robot Challenge will be in the Museum. Go in the main
entrance, and you will be directed to turn right and go into the main hall
towards the windows where you will put down your robots and then register.
Please be there at 9 AM so we can start at 9:30 AM.
- On Sunday we will be meeting in the “Fireplace Room” of the Administration
building. Either take the main entrance and the elevator to the 1st floor,
then look for a staircase going down; or look for the outside stairs that
lead down to the kitchen and then into the Fireplace Room. Please be there at
12:30 PM so we can start at 1 PM, and try to end at 3 PM.
2. The other way, especially for those coming from Philadelphia, PA or
Washington DC is to take Route 95 towards Baltimore City. Take Exit 55 which
will be marked Key Highway. From the exit, there is only one way you can go
on Key Highway. At the Traffic light where the road meets a “T” (I think its
the 2nd light, could be the 1st.), turn left, and you’ll see a very large
crane on your right. Take the entrance on your right immediately before the
crane, and park. Now read the paragraph above identified with an asterisk(*).
Q & A
Question: We’ve had some problems soldering. Do you have any suggestions?
Answer: Soldering is a skill that takes some understanding and lots of
practice.
1. Less solder is better than too much solder.
2. Solder joint should be shiney not grey. If its a dull gray, it means that
the wire moved before the solder had a chance to solidify.
3. Apply the soldering iron to the heaviest part first, but don’t overheat as
you might damage the internal parts of the item you’re soldering. Just apply
the iron till you see the solder melt. Touch the iron to the wire for a
moment, then remove the iron, making sure the wire doesn’t move for about 5
seconds.
4. Removing excess solder is far harder than applying solder. If you find you
have to do it, get some desoldering braid from Radio Shack, put the braid on
the terminal where there is excess solder, and put the soldering iron on top.
The braid will wick up the solder, and remove it from the terminal.
5. If you are getting inferior solder joints, check that surfaces and the
soldering iron tip are clean, and make sure the soldering iron has the tip
screwed in tightly. Sand the surfaces with an emery board or fine sand paper.
Tighten the tip clockwise with a pair of pliers if not getting enough heat.
Q. I have gone through a lot of batteries to test to walk our robot. What can
we do to prevent this from happening at the competition? We don't want our
batteries to give out on us while we are walking the robot. What can we do?
A. Assuming that you don't have defective wiring or electrical components,
the only other cause for high battery consumption would be too much friction
or an unusually heavy body (should be less than half a pound). Or you may be
running the robot too much.
Keep a fresh set of alkaline batteries for the Challenge - that will
minimize the chance of jamming, and will help you over the hurdles. Practice
is good, but too much may cause the parts to wear out - especially #3 and #4.
Q. Can we change our team name? What do the hurdles look like?
A. So long as you don't change your number, you may change your name until
the day you hand in your Written Report.
The two hurdles located 1 foot and 5 feet down the course, are 1/2 inch high.
They are in the shape of a "1/4 round" piece of lumber, the kind generally
used as floor molding. Imagine a 90 degree sector of a one inch circle being
the profile of such a piece of wood stretching across the width of the table
in two places. These strips are attached to the 8 foot tables with masking
tape, such that the round surface is facing the start of the race.
The tables themselves have no rails around the edges, so robots can fall off
the edges, and occasionally do.
Q. Any suggestions on the Written Report and Walking the Robot.
A. Be sure to read the manual carefully with regard to the Written Report.
Use photos and sketches and be sure to label them so that the text ties in
with the pictures. Make the presentation fun to read, not too stuffy, but
include material on the schedule and whether you were able to follow it in
actual practice and why, cost projections vs Actual, and of course note the
Safety practices followed and the Acknowledgments of where or from who you
obtained information or advice.
Be sure you find out how the mechanism jams so that you are sure it won’t
happen during the Challenge competition. You lose one point every time you
touch it to unjam, and that's the equivalent of one minute in the Run.
Q. My robot keeps falling over. What can I do about it?
A. When you are practicing walking, remember that you need 3 points of
contact with the table to hold up the robot (like a 3-legged stool), and one
leg will be getting ready to go to its next position. On a piece of paper
draw a line between each adjacent point of contact, and be sure the center of
gravity of your robot is within these three lines. If it isn't the robot will
fall over. Note that this triangle changes as you switch the leg in contact
with the table.
What complicates matters is that while two of the points of contact (the
skids) do not move, the third point of contact (the leg) will be moving, and
this may affect where your center of gravity should be. Note also that the
weight of the foot (the motor) that is in the air, will also affect where the
center of gravity is.
For that reason, while the sequence of walking operations in the manual
may not be too bad, there are at least two other sequences that are more
stable. It is for you to find what they are. Try to think how you could work
it out.
Q. The legs of my robot keep getting jammed. What can I do about it?
A. When your legs jam, examine very carefully why they are jamming. Is part
of the white L-shaped plastic part coming up and pushing against the tapped
rod or the brass piece (item #4). If you moved the end-stop could you prevent
the plastic part coming up so far?
Is the tapped rod going out too far, and pressing against something?
Again could an end-stop be moved to avoid this?
You may feel that these actions may shorten the stride a bit, but this is
a small loss compared with the consequence of jamming the mechanism.
Now you may find that that the end stops themselves are pressing against
the brass piece. Use a tiny drop of the lubricating grease in package #17
between the end-stops and the brass piece (item #4).
Also check that item #4 does not have too much friction against the wood
block. May need to sand the wood block or move out the collar (item #6) just
a little bit.
After everything is working right, another problem can arise - the end
stops may move after a few minutes of operation, and all of a sudden you
start having problems again. Restore the end-stops where you want them, then
substitute longer pieces of the silicone tubing (item #10) so that there is
no longer a gap and the tube will no longer be able to move. If the clear
plastic end-stop (item #9) is moving, you might want to make this a little
longer as well. If it still moves, put a small amount of super glue at the
end away from the brass piece (item #4). Be very CAREFUL when you use
superglue as it dries instantly and can stick your fingers together, or if
you touch your eyes, it can affect your eye-lids. Note that superglue only
seals in the absence of air, so if its on a surface it never dries and you
may touch it accidentally and get it on your fingers. You need to mop it up
with a tissue. (Only use superglue on the clear tubing end-stops).
A problem with using superglue on an end-stop, is that if you ever need
to change a part (such as #4) the end-stop will be difficult to remove and
may have to be sliced off, and the threaded rod cleaned carefully.
Q. How to we get our robot to walk consistently and reliably?
A. 1. Remember that the walking sequence in the manual may not be the best or
most stable sequence - its just a place to start. Also that walking may be a
little different when the robot body is in place, and it must be in place at
the competition.
2. If your robot tips over, find out exactly why, and what you could do to
prevent it.
3. If the mechanism jams, find out exactly why, and what you can do to
prevent it. Remember there is a packet of lubricant in the kit.
4. The end stops will sometimes move, giving your robot inconsistent
behavior. Sometimes a longer end-stop will eliminate the problem. Once
you’re sure you know where the end-stop should be, you can clean the tapped
rod carefully, replace the end-stop, and add a very small amount of
super-glue to one end. Do this only under supervision, as super-glue sticks
so quickly that it can be hazardous (it can stick your fingers or your
eyelids together) - and be very careful not to get any on the thread where
they go through the plastic or brass parts.
5. Your objective should be to do repeated sequences without jamming -
remember that you will lose a point every time you need to unjam the
mechanism during the race event.
6. Your first objective is just to complete the course with the 2 hurdles.
Then try to do it faster. Seven minutes would be an outstanding performance,
but it has been done in even less time.
Q. We are ready and prepared for the competition. Our robot now does not jam,
we have a nice case built. Anything else?
A. Well done!
Have you practiced over a 6 foot course with 1/2 inch hurdles?
Have you made your flag and prepared materials to present at the Oral
Presentation?
Q. How are the points for this competition actually broken down?
A. Turn to page 15 of the Robot Challenge Manual and you will see a breakdown
of how the points are assigned. (or click here for more information)
Item 1 is the Written Report, which garners up to 25 points.
Item II appears as the second item in Item IV. Disregard it for now.
Item III is the Track event, and it's described briefly. As you can see
it has the potential to give you 40 points - even more if you do a second run
under automation control. What you need to know is that if you save a minute
in running time you gain a point. If the mechanism jams and you have to
handle the robot to unjam it, you lose a point - though you won't lose more
than 5 points max because of this. Note that there will be a repair station
at the event, so make sure that everything is right before you start the
Track event. The judges will be looking (and awarding points) at how well you
work together as a team.
Item IV is the Oral Presentation. You present material you have prepared
(could be posters, charts, just the robot or even a short video) to two
judges who will then ask you a number of questions. Based on your knowledge
of the operation of the robot and the manner of your presentation, you will
receive up to 15 points. Remember that the emphasis is teamwork, so be sure
that all your team members contribute to the presentation.
The second part of the Oral Presentation is the Revue of Fabrication.
Judges will want to look at the workmanship of your robot body, the
originality of the design, and the finish of all the parts. They will also
look at the carrying case. Be sure that the robot body can be lifted up to
the extent that the judges will be able to examine the mechanism underneath.
Max points for this part is 20 points.
The judges will have far more detailed sheets that break these numbers
down into many different categories, but the above data will give you an
overview of the whole process.
Q: For the flag when you say a stiff flag you mean made out of some kind of hard material like poster board or wood?
A: Your flag can be made out of any material, however if it is made out of a stiff material (as you note, poster board or wood) then the team number will always be visible. In other words, if you use cloth, it will be "floppy" and the number won't always be visible.
A: You have been provided a team number. It is on the cardboard box which your robot kit came in. If you have a two leg kit, the number should be 2 digits. If you have a 4 leg kit, your number should be 3 digits. Place your team number on the flag.
Question: Is there a weight requirement for the robot?
A. There is no rule about the weight of the body because adding weight adds to the load on the spindly legs and will probably slow you down. We suggest that the body should be 8 ounces or less, not because it is a requirement, but rather because we have found that the robots seem to work better that way.
Question: How do I enhance traction of the robot.
A: Read paragraph 23 on page 12 of the Manual. Rubber pads with rubber cement have worked quite well for us, but if you have something better, you are more than welcome to try it - we welcome innovation so long as you abide by the few rules that are part of the Challenge. Note that anything not specifically listed as a no-no is fair game!
Q. Do the rules specify if the motors have to be covered by the robot costume.
A. The purpose of the costume is to show your design originality and make your robot look attractive and possibly funny (in a fun way) to the judges and spectators. We have allowed some fairly skimpy costumes in the past, but they don't get many points from the judges.
Costumes have a down side since they can cause the mechanism to get jammed, so the challenge is to have an attractive costume, but make openings for the mechanism so that it doesn't catch hold of any fibers. Make sure that you have access to the shaft of the motors that control the foward-backward motion in case the mechanism gets jammed.
Regarding whether the costume must cover the motors, the judges will be looking for a costume that represents what it is supposed to be. If part of a motor is peeking out but does not overwhelm the overall appearance of the body, that will be fine. If most of what you see is the mechanism, you will have points deducted. Ask your teacher to show you the picture of the dinosaur robot that is in his manual, for an illustration of what you should be striving for.
You also need to remember that you must be able to open up the costume during the Oral Presentation so that the judges can examine the workmanship of the solder joints and the mechanism.
Q. 1. We are getting the threads damaged or worn out in items #3 and #4.
Q: 2. We had a very unusual problem today where the motor would rotate, but there was nothing
gripping onto the threaded rod to make the leg move. After careful inspection we determined that the part in question was the custom arm that connects the short threaded rod that is a part of the back motor to the custom arm that holds the moving leg. We have realized that the threaded rod
has worn away at the hole on the custom arm and the arm can no longer grip the threads on the rod. This has made it so the threaded rod moves in circles, but nothing else does.
A. 1. It is possible that you are not rounding off the ends of the threaded rods after cutting them. Remember that you must check each end by inserting it into the 2-56 nut provided in your kit (item #18). This should be done BEFORE you insert the threaded rods into either part #3 or part #4.
A: 2. You need a replacement part #4, this part gets some wear if you are doing a lot of practicing, so be sure to check that it is in good condition prior to the Challenge event.
Q: We are working on putting the contol units together. When trying to put wire number 30 on, we ran into a problem. In the direction booklet, it says to connect the wire with a white stip to the commonbus and the remaining wire to the terminal. However, our wires do not have white strips so we don't know which one to connect to which. We have a copper and a silver colored wire. The copper wire has what looks like a green string in it.
A: Sometimes we get wire from our suppliers with white stripes and sometimes they come with silver colored wires. Use the silver colored wire where it calls for the wire with the white stripe.
Even if you should get them confused, there are no serious consequences as you need to check that the legs are moving correctly before soldering the wires to the motors. If the motors are moving opposite to what they are supposed to do, switch the wires to the motors, check them again, and if OK, then solder them.
Q: When the threaded rod is placed in the clear tubing, it won't fit inside of the brass tubing.
A: A common mistake is to insert the threaded stud into the clear tubing, and then to insert them into the brass tubing. This cannot work because when you insert the threaded stud into the clear tubing, it stretches the tubing and causes an increase in its diameter. The clear tubing which would normally fit in the brass tubing no longer can do so.
In the procedure described in the manual, the clear tubing still stretches, but the brass tube stops it from stretching outwards, so it stretches slightly along its length. The important thing is that it now clamps on to the threaded stud very tightly, so that when the shaft of the motor is inserted into its open end, the whole assembly is quite rigid, and the theaded stud acts as the leg of the robot.
Follow these instructions:
Drawing 003-1 on page 26 shows the plastic tubing (item 8) between the threaded rod (item 7), and the brass tibe (item 8).
The steps to this assembly are.
1. Cut the plastic tubing the same length as the brass tube, and insert it into the tube.
2. Hold the threaded rod horizontally in a vise (with rubber jaws), so that the end of the threaded rod extends 5/16" beyond the edge of the jaws. Tighten.
3. Engage the assembly from line 1 over the end of the threaded rod and twist it clockwise so that it screws onto the threaded rod. If the plastic tube moves slightly out of the brass tube, realign it as you go along. If your fingers are not strong enough to twist the tube assembly, wrap the brass tube with masking tape to a thickness twice the diameter of the brass tube - it will be much easier to twist on in that way.
4. Continue until the line 1 assembly touches the end of the vise. Remove from vise, and verify with an opened paper clip that that the hole at the other end is 1/4" to 5/16" deep. You will be inserting the shaft of the motor into this hole.
5. Liquid Soap placed in the plastic tubing eases this assembly.
Q: Advice about wiring the power unit to the control unit
A: See updated information about Control Unit and the Power Unit
Q: What is the purpose of the shallow channel (indent) on the side of the wooden body?
A: The shallow channel is to provide the alignment for the two motors as they are being epoxied to the wood block. It increases the epoxy contact surface to the motors (and thus the strength of the bond), and allows the use of a strong rubber band across both motors to hold the motors in position as the epoxy cures. In this way the motor axles are pointing in the exact direction they need to be for alignment with the end holes of the white plastic L-pieces (Custom lever arm and pivot, item #3).
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Q. What is the angle that they use to drill the holes in the wood block.
A. The inclined holes are only used to run the wires between the motors and the 3/8" hole at the back of the robot. They do not need to be precise. There are two angles for each hole, and students should draw a center line for each of the 3/16" holes shown in figure 001, and copy this on to the wood block so as to help guide them to the 3/8' hole. Students may find that if not drilled correctly the 3/16" holes may not reach the 3/8" hole, because of practical constraints. Redrill as needed. Go to the web-page, and click on Students, to get a better view of the drilled wood-block.
Q. When do we register the names of the students in the groups for the competition? Also, who should we be sending this information to?
A. For the 2006-2007 year, visit the Engineering Challenges page at the Baltimore Museum of Industry, by entering: http://www.thebmi.org/content/index.cfm/ContentID/1811/SectionID/537 then go to the bottom of the page and click on: Click here to register online. Also contact Jay Gamerman at jay.gamerman@acrodyne.com to make arrangement for obtaining robot kits and team numbers.
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Q. School did not do so well last year with the presentation portion of the challenge. We wanted to see if there was a rubric that is used for this area. Also, we wanted to see what the general format of the presentation is – should they be talking about their construction and testing process? Or, should they just be prepared to answer questions? We want to make sure that the students do better in this area.
Regarding the written portion of the challenge – were the students supposed to outline their process or were there specific sections that needed to be included into the report?
A. Pages 16 and 16a of the Robot manual cover the written report quite extensively. The Oral Presentation is described on page 16d. Also check this web-page for further information on the Written Report.
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Updated:
11/12/08