The above System is known as an H-Drive. Typically, an H-Drive only has one ridged wheel in the center going horizontal to drive the robot side ways. But that design has a couple large pit falls. One, if the ground is uneven it loses traction and two, if the wheel is driven quickly it tends to slip. These issues combine cause the H-Drive to fail. However, in the design that I developed with my teammate Rachel Fox, the wheels are passively torqued into the ground with a contact force proportional to the speed at which the wheel is being driven. This allows the robot to move omni directionally without ever loosing traction with the ground. You'll see this mechanism in both the 2018 and 2019 robots.