Robot Arm C

[ODoyleRules]

I can put a bunch of prices up too for parts, but that still does not change the reality of what teams are spending. Also, your list is unrealistic. First of all a servo with only 2.5 kg of torque will not have enough torque at the base to put a battery in the north goal. Especially if it is built by your average student. I have ran this event at 4 different invites this season, and will be running it for my fifth tomorrow, and I can tell you. No one has won any invtational I have been at for less then $500. I ask every team that comes in how much they spent on their robot, and in general they are all well over $100.

We definitely know the reality of this event is that teams are spending a large amount of money, but the larger point is that they are not required to do so. I built a functioning robot arm using components below the specs quoted by my brother that was strong enough to lift D-Cell batteries, it just required a fair amount of design work and engineering planning (you don't need a servo at the hub lifting the whole arm if you use a crane or SCARA style arm.)

Our larger point is that in the other building events (with the possible exception of helicopters), kits or predesigned tools are relatively rare. Why is it that teams always revert to such components in the robotics events when far cheaper components are available? I have a few theories, but I won't presume anything in this situation.

Could your crane do all the required steps in the required time? I have my doubts, as I have seen cranes built with similar components as those listed above, and I can tell you they were not competitive at all.
Bottom line is if you are going to be competitive, you have to spend money on this one, plan and simple. There is no $50 solution that will win it for you. Also, I agree with getting away from the kits, but this does not mean that it will still not be expensive.

[chalker7]

Could your crane do all the required steps in the required time? I have my doubts, as I have seen cranes built with similar components as those listed above, and I can tell you they were not competitive at all.
Bottom line is if you are going to be competitive, you have to spend money on this one, plan and simple. There is no $50 solution that will win it for you. Also, I agree with getting away from the kits, but this does not mean that it will still not be expensive.

I never put a gripper hand on the end (because it was a discussion point for the clinic), so I honestly don't know if it could do everything in time (due to it never being run in a competition setting.) However, it was extremely fast and I have no doubt that it would be able to complete every task in time.
I completely disagree that there isn't a $50 solution that can win (if this is such a sticking point, I may just put together an Arduino powered arm with random parts to prove a point.) I do, however, agree that there isn't a $50 solution that has won. The question (which we haven't seen an answer to yet) is why haven't more teams attempted to cut the budgets down? Why do teams insist on using kits (that are invariably marked up) instead of individual components (which will be cheaper.) Whether they are a lot cheaper (my opinion) or just a little cheaper is irrelevant, it would be a cheaper option. Finally, why don't more teams reuse previous components? We specifically wrote the robot arm rules to accommodate parts from Sumo Bots (if you notice the voltage requirements are the same.) Shouldn't that reduce the price dramatically if you are willing to repurpose individual pieces?

[ODoyleRules]

Could your crane do all the required steps in the required time? I have my doubts, as I have seen cranes built with similar components as those listed above, and I can tell you they were not competitive at all.
Bottom line is if you are going to be competitive, you have to spend money on this one, plan and simple. There is no $50 solution that will win it for you. Also, I agree with getting away from the kits, but this does not mean that it will still not be expensive.

I never put a gripper hand on the end (because it was a discussion point for the clinic), so I honestly don't know if it could do everything in time (due to it never being run in a competition setting.) However, it was extremely fast and I have no doubt that it would be able to complete every task in time.
I completely disagree that there isn't a $50 solution that can win (if this is such a sticking point, I may just put together an Arduino powered arm with random parts to prove a point.) I do, however, agree that there isn't a $50 solution that has won. The question (which we haven't seen an answer to yet) is why haven't more teams attempted to cut the budgets down? Why do teams insist on using kits (that are invariably marked up) instead of individual components (which will be cheaper.) Whether they are a lot cheaper (my opinion) or just a little cheaper is irrelevant, it would be a cheaper option. Finally, why don't more teams reuse previous components? We specifically wrote the robot arm rules to accommodate parts from Sumo Bots (if you notice the voltage requirements are the same.) Shouldn't that reduce the price dramatically if you are willing to repurpose individual pieces?

First of all, understand that many schools get their VEX kits for "free." They are purchased for project lead the way, or there are actually programs in many states where if you go to a training session, you get a kit for free. So keep in mind, many times where you see kits it is being used because they are free.
Sumobot parts do not translate well to robot arm. Primarily because most Sumobots ran on motors and these run on servos, and yes I know you can make a motor run like a servo, but many teams do not have the expertiese to do this, or the time to do this. I am well aware that you and your brother are more the capable of using a motor as a servo, I can too, but keep in mind many teams cannot. So what do they do, they fall back on kits, that worked fine for sumobot, but are not effective for Robot Arm. Kids get discouraged, and then they simply stop working on it.

My question to you folks is why not write the rules in such away that they lend themselves better to being ran with robots made out of cheaper parts?

[GoldenKnight1]

First of all, understand that many schools get their VEX kits for "free." They are purchased for project lead the way, or there are actually programs in many states where if you go to a training session, you get a kit for free. So keep in mind, many times where you see kits it is being used because they are free.
Sumobot parts do not translate well to robot arm. Primarily because most Sumobots ran on motors and these run on servos, and yes I know you can make a motor run like a servo, but many teams do not have the expertiese to do this, or the time to do this. I am well aware that you and your brother are more the capable of using a motor as a servo, I can too, but keep in mind many teams cannot. So what do they do, they fall back on kits, that worked fine for sumobot, but are not effective for Robot Arm. Kids get discouraged, and then they simply stop working on it.

My question to you folks is why not write the rules in such away that they lend themselves better to being ran with robots made out of cheaper parts?

I think that fact that batteries and controllers from last year could be used this year was a significant savings. While I doubt that most of the kids could easily reuse all of the parts from Sumo to Robot Arm, that does not mean that they could not use a lot of it. I think part of the problem is a lack of imagination on some students parts who would rather buy a premade kit instead of working the problem. Also in many cases I have seen good arms that have been made with what was probably scrap materials and reused parts, with the only thing that looked new on them being the gripper and some of the servos.

Teams that take the time to plan and work on their design and the construction of their robot arm can find ways around the price of components. The teams the try to throw it together the night before are always going to have trouble.

[chalker7]

First of all, understand that many schools get their VEX kits for "free." They are purchased for project lead the way, or there are actually programs in many states where if you go to a training session, you get a kit for free. So keep in mind, many times where you see kits it is being used because they are free.

And many do not as well... I'm also not specifically concerned with VEX kits, as there are a number of other robot arm kits available in the 200-500 dollar range that I suspect will turn up at competitions throughout the year.

Sumobot parts do not translate well to robot arm. Primarily because most Sumobots ran on motors and these run on servos, and yes I know you can make a motor run like a servo, but many teams do not have the expertiese to do this, or the time to do this. I am well aware that you and your brother are more the capable of using a motor as a servo, I can too, but keep in mind many teams cannot. So what do they do, they fall back on kits, that worked fine for sumobot, but are not effective for Robot Arm. Kids get discouraged, and then they simply stop working on it.

You can also just use regular motors for a lot of the tasks (e.g. a winch on the end of your arm.) You don' need servos for everything. More importantly, servos aren't wildly expensive (unless you're buying servos that are of a much higher quality than required) and the most expensive parts are generally the radio, the receiver and the battery. All of those can easily be reused.

My question to you folks is why not write the rules in such away that they lend themselves better to being ran with robots made out of cheaper parts?

We DO write the rules such that they can be run by robots made from cheap parts (of course, in our opinions.) Whether teams actually do that or not is beyond our control. It will always be easier to spend a lot of money on a device that works out of the box than it will be to plan ahead, source parts, construct them carefully, etc and lots of teams will always take that route. As a result, any "robotics" event will invariably result in teams spending tremendous amounts of money. Robot Ramble was cited earlier as being a cheap event, but when I competed in it my team spent hundreds of dollars on it.... What specific differences made that a "cheap" event vs. Robot Arm being an "expensive" one?

Also, I agree with everything GoldenKnight1 says above

[ODoyleRules]

There were things done when the Robot Ramble Rules were written to ensure that there was no need for high end parts, and that cheap robots could compete. For example, the weight of the objects used were generally light objects. Now Ill give you that there was one set that used 3 C batteries, but otherwise it was maditory that the object were light. The kids had to pick up things like CDs, pennies, ping pong balls, and paper towel tubes, These all posed a challenge to pick up and place, but did not lend themselves towards heavy duty motors.

By putting D batteries in this event, you are unintentionally encouraging teams to use more expensive parts. You could have used 9V and had a similar object to pick up, but at 40% of the weight.

The bottom line is the way this event was created, a more expensive robot will win almost every time as they are generally faster and easier to control due to the nicer parts.

[illusionist]

Just my personal experience-

Our current robot design uses vex motors and controller/receiver on a wooden frame that we built, so it's not a snap-together type robot. The biggest reason is that everything fits well together, no need to look for specific gears or shafts or collars. Also, I have very little experience with the electronic (control) aspect of robotics, and so trying to build a system from scratch using some transmitter I found online with motors, which I don't know if they'll even work with my transmitter, was somewhat of a daunting task. i felt the same way last year with Sumo Bots as well (which btw wasn't run as an event in MI, so I didn't have to worry about it).
So chalker(7), the issue isn't (in my eyes) that teams want something that they can snap together using someone else's engineering or designs, but rather that we don't know how to work with the electronics. Thus, our team ended up using Vex electronics with our own hardware.

With many of the other building events, it's really, really easy to build something on your own that will be fairly competitive. Gravity Vehicle- We bought some wood from Home Depot and built our first vehicle out of some children's construction sets, and it was doing fairly well. Helicopters- wood is unbelievably cheap, and even if you do buy a kit, you have to build it yourself anyway. The wood pieces in a kit don't magically snap together like they would for a robot kit. Battery Buggy (in Div B a while ago)- We used a balsa board as the chassis, some eye hooks for holding the axles (threaded rods), a couple switches from Radioshack ($2), some AA batteries, and some thin wires that we found around the house. and a small DC motor that I got from an old toy. We got 9th two years ago at state with a less than $12 vehicle (the vehicle could have done better, we messed up in alignment).
So my point is, there are no difficult electric components associated with those events.

As of now, I'm not sure how the event could be modified so that it doesn't seem so difficult, but I'll post whatever I think of.

[harryk]

I guess I'll chime in now
First off I have to admit that I have spent a considerable amount of money to build a rather fancy, custom arm.
However I do believe this event can be done on a low budget of less than $100. In order to do so ultra cheap servos and control equipment would have to be used and be used in a crane style design. That way everything can be counterbalanced and if built correctly will place very little load on the servos themselves. I think a properly designed and practiced arm could successfully achieve a perfect score. Though it would take much much longer than the allotted 3 min. No matter how much you practiced, the slow/overly quick movements and lack of precision will make it impossible to do this event quickly. This is where high budget devices that include more programming and high torque precision servos will prevail. So in short, if say 10min were given, then cheap cranes could defintely be competitive with thousand dollar arms

Just an interesting calculation:
There are 20(?) objects on the board, that means only 6 seconds are available to move each object, which for an entire sequence of aligning, gripping, lifting, moving, and releasing that's not very much time

[FueL]

7. The pencils seem to be a problem for whether they went out of bounds or not. It would be better if the field was on a raised surface (instead of surrounded by tape) and if the objects touched the floor, they would be considered out. And again I like time as a time breaker at some level.

From my experiences while practicing, it's incredibly easy for the end pencil to go out of bounds because the gripper isn't perfectly aligned with the pencil when it picks it up. The pencil ends up shifting direction and sometimes knocking other pencils out too. They're usually only out of bounds by maybe a quarter of a cm or so and I feel think some event supervisors would overlook it, but it's risky.

Has anything like this happened to anyone else?

[chalker]

Good discussion. Just wanted to point out my original comment was in response to the following from wlsguy:

All schools should be able to compete at a similar level with a reasonable amount of money.
Science Olympaid should be more about effort and less about $$$$.

As the comments have shown, for some reason teams aren't wanting to put in a ton of effort on the design. It amazes me that certain people will become essentially materials sciences experts for events like helicopters, but don't want to do rather basic electronics stuff for robot arm.

Regarding this:

My question to you folks is why not write the rules in such away that they lend themselves better to being ran with robots made out of cheaper parts?

The D battery weight is definitely a good point we will revisit for next years rules. Are there other aspects of the rules that you feel also contribute to this?


Finally, if lots of schools are getting Vex kits for free. then what are they spending hundreds of dollars on? I don't understand where the expenses are.