<p>I'm not entirely sure if this goes to drones or electronics. Feel free to move it.</p>
<p>I'm working on a completely autonomous drone system. It is not only supposed to fly autonomous missions, but also to charge itself. For this to work, It must land precisely on a charging platform, so that electrical contact points on it's legs meet with contact points on said platform. However, I'm a programmer and not an engineer, so the electronic parts are always tricky for me. I've made a design, but I'd like somebody to make a sanity check on this and say if it will end in a working solution, a fiery inferno or anything in between...</p>
<p>The following is a design that is supposed to cake care of charging. Upon landing, it disconnects the drone from the battery and powers it via a power source on the ground (the drone carries a companion computer which must keep working). Also, it starts charging the now discoupled battery. Before takeoff, charging is stopped and the battery is reconnected.</p>
<p>The following diagram illustrates this (Red = positive, black = negative, green = signal)</p>
<p><a href="https://i.sstatic.net/37tf5.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/37tf5.jpg" alt="enter image description here" /></a></p>
<ul>
<li>Control: Controller for relais1 and -2. May be a microcontroller or a RPI, I haven't decided yet.</li>
<li>Relais1: Mechanical relais with NC and NO contact.</li>
<li>Relais2: Mechanical relais with NO contact.</li>
<li>SSR: High current solid state relais</li>
<li>Batt: Drone battery (LiPo).</li>
<li>CHR: Charging electronics, connected to the balance charging port of the battery.</li>
<li>PWR: Power supply via the charging platform. Voltage can be set to match the battery's cell count.</li>
</ul>
<p><strong>Landing</strong></p>
<ul>
<li>The drone lands and connects to the charging platform.</li>
<li>Control enables Relais2 which closes it's NO contact. The drone is now supplied via battery and charging platform.</li>
<li>Control enables Relais1
<ul>
<li>Relais1 opens NC contact. The self hold contact of SSR is disabled, SSR opens it's contact, cutting the connection between drone and battery.</li>
<li>Relais1 closes NO contact. CHR is now powered and starts charging Batt.</li>
</ul>
</li>
</ul>
<p><strong>Takeoff</strong></p>
<ul>
<li>Control disables Relais1
<ul>
<li>Relais1 closes NC contact. SSR gets activated and powers itself via it's self hold contact. The drone is connected to Batt.</li>
<li>Relais1 opens NO contact. CHR stops charging Batt.</li>
</ul>
</li>
<li>Control disables Relais2, which opens it's NO contact, cutting the connection between drone and charging platform. The drone is now powered via battery.</li>
<li>The drone takes off.</li>
<li>During flight, the battery is connected to the rest of the drone via SSR, which powers itself with the self hold contact.</li>
</ul>

CC BY-SA 4.0
2022-09-01T17:09:23.780Z
I see the pros and cons of both, but would sitll argue a NC contact for mains power while in flight is a safety concern that trumps having to hold it open when charging/idle
Brydon Gibson
CC BY-SA 4.0
2022-09-02T06:58:19.150Z
@Brydon Gibson It totally agree that this is a safety concern. Every forum question regarding power switches I found so far received that answer for good reason. However, my case is different. The power switch no is convenience, so I don't have to rip apart big power cables anymore, it is a bare necissity for my project to work. I use the self hold circuit, so the connection is not based on the Control, but only on the SSR during flight, but I will have to accept the remaining safety concerns.
user3792852
<charging><autonomous>
Will this concept for completely autonomous drone charging work
user3792852
# Will this concept for completely autonomous drone charging work

(Asked by: username_0 on 2022-09-01)

I'm not entirely sure if this goes to drones or electronics. Feel free to move it.

I'm working on a completely autonomous drone system. It is not only supposed to fly autonomous missions, but also to charge itself. For this to work, It must land precisely on a charging platform, so that electrical contact points on it's legs meet with contact points on said platform. However, I'm a programmer and not an engineer, so the electronic parts are always tricky for me. I've made a design, but I'd like somebody to make a sanity check on this and say if it will end in a working solution, a fiery inferno or anything in between...

The following is a design that is supposed to cake care of charging. Upon landing, it disconnects the drone from the battery and powers it via a power source on the ground (the drone carries a companion computer which must keep working). Also, it starts charging the now discoupled battery. Before takeoff, charging is stopped and the battery is reconnected.

The following diagram illustrates this (Red = positive, black = negative, green = signal)

[![enter image description here](https://i.sstatic.net/37tf5.jpg)](https://i.sstatic.net/37tf5.jpg)

* Control: Controller for relais1 and -2. May be a microcontroller or a RPI, I haven't decided yet.
* Relais1: Mechanical relais with NC and NO contact.
* Relais2: Mechanical relais with NO contact.
* SSR: High current solid state relais
* Batt: Drone battery (LiPo).
* CHR: Charging electronics, connected to the balance charging port of the battery.
* PWR: Power supply via the charging platform. Voltage can be set to match the battery's cell count.

**Landing**

* The drone lands and connects to the charging platform.
* Control enables Relais2 which closes it's NO contact. The drone is now supplied via battery and charging platform.
* Control enables Relais1
  + Relais1 opens NC contact. The self hold contact of SSR is disabled, SSR opens it's contact, cutting the connection between drone and battery.
  + Relais1 closes NO contact. CHR is now powered and starts charging Batt.

**Takeoff**

* Control disables Relais1
  + Relais1 closes NC contact. SSR gets activated and powers itself via it's self hold contact. The drone is connected to Batt.
  + Relais1 opens NO contact. CHR stops charging Batt.
* Control disables Relais2, which opens it's NO contact, cutting the connection between drone and charging platform. The drone is now powered via battery.
* The drone takes off.
* During flight, the battery is connected to the rest of the drone via SSR, which powers itself with the self hold contact.

**Tags:** charging, autonomous
> **Comments:**
> **username_1**: I see the pros and cons of both, but would sitll argue a NC contact for mains power while in flight is a safety concern that trumps having to hold it open when charging/idle  
> **username_0**: @Brydon Gibson It totally agree that this is a safety concern. Every forum question regarding power switches I found so far received that answer for good reason. However, my case is different. The power switch no is convenience, so I don't have to rip apart big power cables anymore, it is a bare necissity for my project to work. I use the self hold circuit, so the connection is not based on the Control, but only on the SSR during flight, but I will have to accept the remaining safety concerns.  

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## 0 answers

