January 26

As we enter the second week, we have been designing the main structure of this year’s robot. Working over the week and going into the weekend, we’ve made many sketches and calculations along with dimensioning and optimizing the alignment of mechanisms.

Starting from the base up, we have the drivetrain. This year we have decided to use a Tank Drive because this fast pace game challenges us to have speed in our driving rather than accuracy. We saw many advantages to a Tank Drive than a Swerve drive in that testing a swerve drive would be very risky for our software team. We have never used a Swerve Drive for our robots before, although arguably useful, the better alternative is the Tank Drive. Additionally, our drivers are already familiar with the controls that accompany it. This simple design allows us to maximize the spacing on a 29.5x29.5 square inch drivetrain and reduces the spacing issue we’ve had in the past between mechanisms and electrical designing.

                                   

Moving on from the drivetrain, the intake has gone through multiple prototypes and testing. We wanted to make sure that we understood the game piece and the amount of compression we used so that the intake process was smooth and faultless. Hence, it was critical that we tested the intake first to establish that compression baseline. After days of testing and revisions, we have come down to some finals thoughts: the intake should be compliant in that the stiff ball wouldn’t break a stiff intake, it should also be dropping down on the balls instead of pushing them away like the action of a 4-bar linkage mechanism, and finally it should spin pretty fast ~900-1200rpm to have fast cycle times in-game and successfully rack up low-bouncing balls. With our current design, all these points have been addressed but revisions will always be made - a redesign of the back “intake”/wall needs to be done as it currently may interfere with the Superstructure mechanism which we will discuss in a second. Either way, the intake is near completion and will be lightly pneumatic-powered for compliance.

                                 

This year, we have also decided to make a Superstructure to store balls and increase shooter height. This structure essentially sends balls up to the shooter mechanism through a series of wheels and belts. Inspired by Jack in the Box team #2910, we thought it would be a good idea this season to have a superstructure and have it function centrally in the robot. The belts driving the ball upwards will basically increase the height of the shooter - as the shooter is attached on top of the structure. With our goal to “dump” balls into the lower port for fast ball cycles, the super structure allows us to quickly shoot with optimal accuracy. We have also been prototyping this mechanism to ensure the ball has proper movement and travel pathing. From what we have seen and tested, along with critical design reviews, some revisions will be made that advance the Superstructure with efficiency.

Rising up from the Superstructure is the shooter mechanism. Like last year’s Whirlpool design, our shooter is a hooded one, but without the turret component. Essentially, a turret would ideally, but be a bit complex to incorporate into our design because it would be mounted high up on a static structure. Furthermore we would have some trouble with wiring and angle alignment during gameplay. We don’t want the turret to intersect with the climb and so sticking with a modular positioning of the shooter on the superstructure would currently be the best option to go with. The shooter really consists of a single flywheel with a small rocker-wheel in the back to reduce some backspin. From prototyping, we figured we needed backspin to create a parabolic trajectory, but too much backspin limited the horizontal movement of the ball path and was often inconsistent. The addition of the rocker-wheel should prove useful, and with the right compression that we have adjusted in multibody-geometry sketches, the shooter should be able to project the ball accurately into the Upper Hub with a “shooter’s touch.” With a lead-screw driving the hood on the shooter, we have practically all we need to shoot accurately into the Upper and Lower Hub.

Finally, we reach the tallest part of the robot: the climb. Our goal this year is to at least be able to climb onto the high rung - giving us 10 out of the 16 alliance points we need during endgame to obtain the climb ranking point. In this design, we can start the middle rung and traverse up to the high rung. This is seen through the middle hooks latching onto the middle rung and the outside parallel telescoping arms extending to reach the high one. A critical point in this design was getting our center of gravity to be concentric to the outer climb’s pivot - which decreases stress and tension for a fast and efficient climb. With a single winch system to pull the robot up, our climb should effectively traverse the rungs from mid to high. In any case, if we decide to spend more time shooting during the last 30 seconds of the game, we can resort to climbing on the low rung.

The season so far has been really exciting for all. We have been using our CNC a lot and have started to work on components of the drivetrain for the robot. We have sent out t-shirt design challenges for all members on the team to participate in and our marketing team shall reveal a finalized design soon! Even though the season started nearly 2 weeks ago, you really can’t get enough of, “IT’S GO TIME BABY!” - wish y’all a great day and stay tuned for more.