During the spring of 2016, we realized that the Gen3 robots had issues driving straight, due to the wheels having different angles to one another. We decided to use the same angles between the wheels. The main reasons for this were the ease of controlling a robot and a higher speed in all directions. This meant there was less space for the dribbler/chip/kick module. Also there wouldn’t be enough space to fit the current solenoids in with the current wheel module. In the end we decided to do a full redesign, only keeping several smaller items, like the old wheels.
The Gen3 robots were the first robots to have dribbler unit that could dampen the ball when it received the ball. Although this was a good idea in theory, in practice the dribbler was too unstable and started shaking uncontrollably when the motor went too fast. The dribbler for Gen4 was redesigned to keep the dampening but remove the uncontrollable shaking. The dribbler also had to be smaller, since the new angles used for the motor meant there was less room. Since the motor of the dribbler is inside the dribbler itself, we had to figure out how much smaller the dribbler could be while still having enough room for the motor.
The old chipper would also no longer fit. We had to find a new way to get the new chipper in place, while also leaving enough room for a kicker. This was eventually done by making slots in the bottom plate where the chipper could fit through
The kicker had to fit in between the chipper, the only way for it to fit was to make a T shape, where the chipper could fit around. By doing this the kicker would still have a reasonable contact surface while still being able to fit around the new chipper. The kicker is also mounted on a new rail. Instead of trying to make something themselves we decided to order small linear guides for the kicker to slide over.
We are always looking for ways to make the robot lighter. The Gen3 hood was made lighter by using an aluminum frame and covering that with black plastic. This year we decided to take that one step further. They decided to create a mold of the dimensions and vacuum form the hoods. By giving the sides a slight inclination of a couple degrees the hoods would also be stackable, making it easier to travel. Since the hoods are vacuum formed out of 1mm sheets of black plastic, they are extremely light.
We also decided to shave off even more weight by 3D printing several parts. The 3D printed parts were the module for the battery and on/off switch, the capacitor holders, and the motor modules.
We also decided to make a redesign of the motherboard and use a different CPU. The biggest improvement over the old motherboard is the modularity. The new design consists of a main motherboard and several smaller modules that can be attached to the motherboard. The modules are the CPU, motor controllers, and sensor board just to name a few. This allows us to make a complete redesign of any of the modules in the future, without having to create a new motherboard as well.