Solenoid Assembly
This 23-24 mechanics team decided to change the last solenoid to flat solenoids. This greatly benefits the space needed for the solenoids in the bottom assembly. The possibility to change to flat solenoids is made possible by changing the back wheel placement. The solenoids are used for letting the robot kick and chip.
Specifications
| Spec | Value | Unit |
|---|---|---|
| Kick speed | 8 | m/s |
| Number of windings | 546 | – |
| Number of layers | 6 | – |
| Wire Length | 42.34 | m |
| Wire Diameter (ex insulation) | 0.5 | mm |
| Resistance | 3.8 | Ω |
| Capacitor capacitance | 2* 1500 | μF |
| Working voltage | 250 | V |
Working principle
The holders are used to clamp both cores and make sure they are in the correct position. They are made of C45 steel to make sure they concentrate the magnetic field of the solenoid. Furthermore, two plates of C45 steel are added to create more shielding around the solenoid and help protect the kicker-chipper board.
The plunger is the moving part of the solenoid. It consists of two materials C45 steel and aluminium. This is done because the relative permeability of the steel is higher than the aluminium (Engineering Toolbox). The solenoid's main working principle is that the armature (plunger) is always attracted to the centre of the core(Youtube). The holders and the plunger are both made at MCM. The plungers are retracted using springs, which are not quite strong such that not a lot of energy is lost; however stiff enough to retract them to the correct position. Furthermore, a PC-printed part is added to the kicker plunger. This has a curvature and will allow us to kick straight.
The solenoid's core is designed such that the plunger fits in it and can hold the copper wire. The core is made of PETG with 100% infill and is printed on a Bambu Lab P1P. PETG is chosen due to its strength and its resistance to heat before it deforms.
The solenoids are winded at Beckmann. The connector is soldered by RoboTeam in a later stage.
The drawings for the plunger and the holder and the stl-file for the core can be found here
Simulation and Experiments
This year's electronics team did a simulation of our kicking mechanism. They wrote their results in a pdf with some pictures. They used a simulation tool in combination with SolidWorks. When questions about the simulation results you should reach the electronics team of 23-24.
The results can be found here:
Furthermore, the mechanics and electronics did some testing with the help of Demcon. This was done because the kicking mechanism first could kick at 4.5 m/s and could not find out why it was not shooting the required 6.5 m/s. The conclusion was at the end that the capacitance of the capacitors was too low.
You can find some data here:
- Excel sheet data