Front Assembly

The front assembly is the mechanism we use to keep the ball with us during a game. This year a redesign is completed to increase the performance of ball handling. The main principle used in this design is to give the ball a backspin to keep the ball at the robot.

Compared to the last design we added an extra degree of freedom in the damping mechanism to the design. This year we make use of two side dampers and one rear damper. The two side dampers are made by molding 60A Polyurethena Rubber, gotten from Silicones and More. The rear damper is 3D printed from TPU95A using the Ultimaker S5, the shape of the rear damper allows some flexible & damping performance.

Also, the dribbler bar is changed, as where it now is a cylinder shape without a spiral as in the previous design. This is done to have a simpler design of our bar which is also more robust. The cylindrical shape has of course a lower ball-centring performance compared to the spiral shape however the advantages of less wear led us to change it to this design. Where in the previous design the spiral quicker wears the ball centring performance significantly decreased and with that also lowered the ball handling performance.

The molds are 3D printed from PLA both for the dribbler and the side dampers as both objects do not need a great surface finish. Also, it helps to get from idea to prototype really quickly and is cheap to produce.

Also, the gear used is changed as they are now custom-made by Hankamp. The ratio is now 30:18, where 30 is connected to the motor and 18 to the dribbler shaft. Both are glued to the shaft using Loctite 638. The custom-made gears are chosen as no commercial gear fitted in our design.

A drawing of the gears can be found here:

• Gear 30 teeth
• Gear 18 teeth

The Dribbler Motor is from maxon. This is a 24V brushed DC motor. The electronics subteam added a motor driver to allow for a current limiter. This allows us to better control the ball. A downside is that the motor comes insanely hot and therefore it is advised to switch to a brushless motor and think about adding a temperature sensor.

This year the front assembly is also changed to add the new ball sensor design by the electronics subteam. This is a break beam sensor which will help to detect the ball more accurately.