„EVE“ - by Fürst Ruprecht ( I only do four-wheel drive )

Stand 11.04.2022:
Vom störungsfreien Betrieb bin ich wohl noch weit entfernt.
Immerhin funktioniert nach 3 grausamen Tagen das Fahren und Lenken per Fernsteuerung.

Der Traktor lenkt an der Vorderachse (starre Ramenverbindung): Dabei schwenkt die Hinterachse leicht ein (sehr wichtig bei Autobahnfahrt!). Der Lenkeinschlag wird an Vorder- und Hinterachse gemessen und bei Soll/Ist-Abweichung steuert ein Drehzahloffset an den Rädern entgegen. Die einzelnen Raddrehzahlen werden aus dem Istwinkel der Räder berechnet. (Es geht auch das Sollsignal. Dann wird die Lenkung schneller und es gibt entsprechend Schlupf)
Der Traktor lenkt an der Hinterachse: (hier ist die Achse drehbar am Rahmen befestigt)(Vorn kann auch Hinten sein - Geschmackssache). Also genauso wie oben.
Der Traktor lenkt an beiden Achsen: Hier habe ich das Verhältnis von Vorn zu Hinten 1:1 gesetzt. Man kann auch dynamisch von 1:0 bis 0:1 stufenlos verändern, ist aber recht schwer in der Bedienung.

Gruß Fürst Ruprecht

View attachment IMG_6981.MOV

View attachment IMG_6980.MOV

View attachment IMG_6978.MOV

View attachment IMG_6979.MOV
 
Work status:
Attention !!! - I use my own board, which is not compatible to anything. Therefore, the code serves as a suggestion for people who want to use stepper motors as a drive - because everyone knows that stepper motors in lawn mowers are much better and cheaper than BLDC motors and do not burn out all the time - Hahahaha !

Gruß Fürst Ruprecht
 

Attachments

Today the prototype made its first appearance on the lawn. Unfortunately, my two different self-soldered perimeter sensors don't work - shit. And where is the setting for the steering speed in the pfod app - I thought I had already done something there??? So the auto mode doesn't work. Then I drive with the RC remote control. It's cold outside, the wind is icy. There is almost no driving noise from the mower. The driving speed is sufficient, no problem with step losses. The current specification for the stepper is 500mA (1200mA possible). Very well. Unfortunately it is too cold to make more precise observations. Parts for the perimeter sensors will arrive tomorrow and hopefully the weather will improve. Greetings Prince Ruprecht
 
Where do you live? Here is sunshine :-D
But it's getting thicker now, it'll probably rain soon.
 
Auf meiner Burg natürlich - was für eine Frage.
Die Wettervorhersage spricht von 16° und 14Km/h Wind.
Es sind hier auf dem Berg aber nur 13° auf der Skala und > 20Km/h Wind aus Nord/Ost - gefühlt ziemlich kalt, trotz Sonne den ganzen Tag über.
 
Tried driving in automatic mode in the semi-dark last night. A cable on the perimeter sensor was loose -> short circuit -> big fireworks -> 5V power supply dead -> Teensy dead -> rest in peace
 
Current status: the 4-wheel handlebar drove very well on the lawn, was surprisingly quiet and also significantly faster in relation to the Prototype2 (what you probably don't need). The principle works!
Nevertheless: what is annoying is the space required for the turning wheels.
That's why I've now rebuilt it for the second test. The wheels are close together and are fixed.
As soon as my Teensy type "Feuerwerk" has been replaced and Bernard's latest code works for me, there will be the next test drive.
I will possibly use four small knives for the mower, which are driven side by side as a cutter bar via belts and two motors - we will see.
 
Da ich auch noch ein paar Stepper Motoren rumliegen habe, werde ich mich damit auch mal beschäftigen. Mir schwebt da ein 4WD vor, aber ohne Lenkung, so wie der Ambrogio Wipper.
Meinst du der Stepper Motor schafft einen 19cm Mahteller oder lieber 2 kleine?
 
Beim Mähmotor würde ich keinen Stepper benutzen. Ich denke, das kann nicht funktionieren. Das Grundproblem ist es zu erkennen, ob er außer Schritt gefallen ist, dann steht er quasi und mit welcher Frequenz man dann weiter macht. Evtl. würde das mit einer großen Schwungmasse (Sicherheitskritisch) und einer externen Drehzahlüberwachung funktionieren.
Mähmotor -> China-brushed ! Was spricht dagegen ? Wir haben im e-Auto auch wieder Trommelbremse.

Ambrogio -> so wird mein jetziger Test
 
And which way should I go now?
Ambrogio principle => no adaptation of the sequence control, take over the current programme status.
4-wheel steering => modify all setMotorPWM commands, if necessary also the sequence control.
 
I would say Ambrogio principle. You'd have to try it out and see how it handles on the grass.
 
Video1:

Video 2:
View attachment IMG_7008.MOV
At the bottom of the incline you can hear the step losses. The cause is the excessive acceleration and the phase current limited to 500mA. The wide tires (Show-Mower) don't have enough grip, but they don't press down the lawn as much as those of the PT2. I have fixed the axles, they twist only slightly in the longitudinal direction. From my point of view, twisting the axles is absolutely necessary, otherwise a safe alignment is not possible (with these tires)
 
I drove in automatic mode for the first time today. Looking good so far. But I didn't know how to change the length of the track (developer mode!!!)
 
Mower drives. Chassis is ready. Housing is still missing. Blade is not mounted yet.
Two 24V mower motors with 30 watts each approx. 7000 rpm at idle. Mow-Driver is a Mosfet circuit like the Power-PCB but with buffer capacitor, heat sink and fan.

Problems:
- Perimeter coil left cannot be inverted.
With perimetercoil right it works.

- Mower turns only half of the given angle (180° instead of 360°).

- esp32 -connection is lost (maybe because of the missing buffer capacitor), but esp dials in again after a short time.

More soon.

Greeting Prince Ruprecht
 
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