The robot is almost complete and not a moment too soon. A few things need to be tweaked and the lift for scoring baskets needs to be complete. Those things should be done in a couple of hours, and then we just need to add the electronics and assuming all goes well, we should be done with the robot. But knowing this team, there will probably be problems anyways.
We had three designs that were being prototyped, two were dumpers and one was a shooter. The voting was close so our mentors decided that we would do two manipulators, a shooter and a dumper. Now we are coming up on the deadline and we still aren’t done, close, but not done.
Hey all, we have had a busy couple of weeks! FIRST has announced the 2012 robotics challenge, this years game is called Rebound Rumble. For the past two weeks or so the team has been super busy prototyping and designing on new robot! We built the major field items, such as the hoops and bridge, and are all ready for a robot to drive on them. Speaking of robots, the build team built a c-base frame for the programmers to test all of the electronics on. The entire team is still working on designs for a ball manipulator, hopefully we will have a final design chosen by Sunday at the latest. Looking ahead we are building the frame this week ( bolt together this year, no welding) and finishing the cad of all the designs. We hope that we have a good season!
This weekend we wired up our ultrasonic sensors, which will be used to stop the robot once it is close enough to the scoring pegs in the autonomous period. We ordered two LV-MaxSonar-EZ4s from MaxBotix and wired them up in “chaining mode.” (Maxbotix provides instructions here [PDF].) In this configuration the two (or more) sensors take turns sending out ultrasonic pulses, preventing interference between the sensors. We tested this out on a breadboard and discovered that the sensors do interfere with each other when used without the chaining mode, at least when they are within a few inches of each other. In chaining mode, however, they do not interfere with each other.
After wiring the sensors, we discovered that one of them was getting burningly hot just a few seconds after turning on. The culprit seems to be the PIC microcontroller on the EZ4′s PCB. We contacted Maxbotix and they very quickly sent us a replacement.
With wheels and transmissions mounted on our welded robot frame we were able to mount and test two US Digital E4P encoders to our Toughboxes. Meanwhile we have been planning locations for all of the electronics. Last year we focused on compacting all of our electronics into a small space and ran into issues with that at competition. This year we are taking a completely different approach and spreading out electronics out across several boards all mounted in easily accessible locations.
On the coding side, we have all of our teleoperated period code written for either closed-loop speed control (using the Jaguars and the US Digital encoders) or standard voltage control. Closed-loop speed control will allow us to specify the exact speed at which each motor should run, rather than simply giving the motors an arbitrary percentage. In the end, though, it will come down to which mode the drive team finds more accurate. We also have a full prototype of our autonomous code using ultrasonic distance sensors and the kit of parts line sensors. More details on that coming soon.
Ok, it has been a crazy past couple of days. We got our chassis in on Tuesday, and then our bearing blocks were made by Thursday. We have had to make some adjustments due to things bearing broken and out of square, but we plowed through and this past weekend the transmissions and all four wheels were mounted. And I am glad to say that all four wheels touch the ground at the same time (what a relief!). We also got the battery mount, mounted. On our to do list, our arm, a double jointed one, is put into solidworks and we ordered the materials for it today. We will hopefully get those in soon and go into full steam ahead for machining the arm parts. Our claw is almost completed in solidworks, and the parts for it have also been ordered. The minibot is going well, it goes up the pole in around two seconds, and the minibot deployment system is being worked on now. All in all, everything is going well, and we will have a driving robot soon!
Logomotion
Tonight (February 2) we finally reached a large milestone. Our team’s minibot successfully, for the second time, reached the top of the ten foot steel pole that will be part of the bonus period in this years competition. After many days of prototyping, successes, failures, and learning experiences Eli, Mr. Beachy, and I have been able to create a very quick minibot. Our minibot’s currently takes 2.5 seconds to reach the top of the pole from the very bottom. We still need to organize and design our deployment system and “ignition system” in order to apply power to the motors from the battery.
The minibot has been a very tough challenge this year. There are an unlimited amount of possibilities that will enable our small robot to climb to the top of the pole. Our challenges have been speed, weight, and durability. We have began prototyping the minibot, discovering many new possibilities that will allow us to reach our final goal. Gear placement has been a large issue in allowing the minibot to have powered wheels, because of this many custom parts are being made out of the allowed polycarbonate and aluminium sheet metal.
The build team has been busy with prototyping . We have two different designs for a arm, a double jointed or a high pivot telescoping. We also have several different manipulators being prototyped, we have two standard claws, and then one with a built in wrist. Besides the claws, there is a wheel design being made. Our chassis has been modeled in SolidWorks, and we shipped it off to the welder. It should get back to us tomorrow (hopefully), and we will then mount everything onto it. We decided on using the AndyMark toughbox for our gearbox. We are using dual 8″ AndyMark sticky wheels in the front, and then the dual 8″ Andymark omni wheels in the back. We hope to get the final design for both the manipulator and the arm decided on tomorrow, we will then put those into solidworks and build the final version. The minibot is being prototyped on, and we haven’t made a decision on how to deploy it yet. We hope to be done by the end of week four, to give us plenty of time to drive and test.
Last weekend we mounted the kit of parts line sensors and tried out some very simple line tracking code. We obviously were not aiming for perfection or speed (actually, we we didn’t even intent for it to be able to follow the fork). This was mostly just a test of how the line sensors detect the tape.
We are hoping to get two additional line sensors, but obtaining more line sensors seems to be difficult, since the factory has a 3-4 week delay.
The FIRST® Robotics Competition is a high-school robotics competition that inspires students to pursue engineering and teaches them about the rewards and challenges of working together under pressure.
