More Mule then Rover?

[Tommy_T]

while waiting on the front drive motors to get here I have time to work
on the chains for the front wheels.

replacing the links with smaller ones in hopes of keeping snow from bouncing
out of the bucket because of the chains.






also to reduce current needed for skid steering I replaced the 9.5" wide tires
with 6.5" wide tires

[Tommy_T]

first tests of the four wheel drive went sweet!

I also used the same analog voltage to control both sabertooth drive.

it was easier to install the motors I got today($70.00 + free shipping from ebay)
without the bucket on the mule, first test was without the bucket.

tested with 80A fuse on the sabertooth 2x60, and a 80A fuse on the sabertooth 2x32.

next test is with the bucket installed(adds 84lb to the front wheels)

I received a 100A current meter for the mule, going to be interesting seeing the current
loads with a full bucket and using skid steering.

While I still think I can use skid steering, gotta be ready for a plan B

[jwatte]

I'd love to see that steering setup built :-)

[Tommy_T]

I'd love to see that steering setup built

jwatte, looks like I don't have to, connected the current meter and tested current
value without the bucket and doing ZTR (26A), then installed the bucket and did
the same test(36A), then had next door neighbor(weights 280lb) stand in the bucket
doing ZTR(38A), I think it reduced the weight on the back wheels with heavy loads.

tests done on hard dry surface(blacktop).

interesting, ZTR current values are much greater on grass surfaces(50A)

I'm also thinking the 3.5 engine is good for this build, seems I can get by with 1200W
charging on the 24v(sweet!)

Note: if I do end up building the steering system in image above , the steering motor would have
(2) sprockets , one #40 chain for right drive motor, then one for the left.

[jwatte]

Yeah, I've noticed that grass is a motor killer.

[Tommy_T]

After using the Mule for a few summer/fall season tasks(pulling, and carrying things)
it is clear I'm going to need to steer the front wheels(tears up the lawn). I got a feeling
that with the chains installed it is also going to tear up my driveway over time.

I checked the stock rack, I have the steel stock.

but, because I want the front wheels inside the width of the bucket/plow I may need
to go with a 10" wheel in front, or move the 13" wheels back, but that would reduce
the weight the mule can lift.

[Tommy_T]

plan A for remote engine start.

the engine is going to have it's own arduino nano with a (4)relay shield(because I have one)
(1) relay contact(NC) for the engine kill control
(1) relay contact(NO) for the engine starter relay(120A 12vdc .3A current draw)

using a voltage divider circuit(with diode and cap) connected between the engine's alternator,
and the arduino's (A0) input.

to start the motor the mule's controller(arduino mega) outputs a digital LOW to the engine's
arduino nano as a digital input(pinMode(3,INPUT_PULLUP)

with this setup the engine's carburetor is fixed to the rpm needed for the mule's alternators.

with the engine spinning at the starter motor rpm the value of the nano's (A0) is max of 860,
with the engine running at idle(1900rpm) the (A0) value is 1023.

the engine's nano with a low on digital input 3 energizes the engine kill relay, then if (A0)<900
energizes the starter motor relay, once (A0)>900 the nano de-energizes the starter relay.
if (A0) drops below 900 the relay is re-energized.

if engine is started and (A0)<500 then wait 3sec. then restart engine.

once the digital input (3) goes HIGH both relays de-energizes(killing the engine).

const long interval = 500;
unsigned long xMillis=0;
unsigned long pxMillis = 0;
int start=0;
int started=0;
int alt=0;
void setup() {
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
pinMode(7, OUTPUT);
pinMode(3,INPUT_PULLUP);
digitalWrite(4, LOW);
digitalWrite(5, LOW);
digitalWrite(6, LOW);
digitalWrite(7, LOW);
Serial.begin(115200);
}


void loop() {
xMillis = millis();
if (xMillis - pxMillis >= interval)
{


alt=analogRead(A0);
if(started==1 && alt<900){delay(3000);started=0;}
if(digitalRead(3)==1){start=0;started=0;digitalWri te(7, LOW);digitalWrite(6, LOW);}


if(start==1 && started==0)
{
if(alt<1000){ digitalWrite(6, HIGH);}
if(alt>1000){digitalWrite(6, LOW);started=1;}
}
if(started==0 && start==0)
{
if(digitalRead(3)==0){start=1;digitalWrite(7, HIGH);}
}
pxMillis= xMillis;
//endtimmer
}
//endloop
}

[jwatte]

Now to start the engine only when battery voltage falls below X, and then stop it when voltage reaches full charge again :-)

[Tommy_T]

Now to start the engine only when battery voltage falls below X

jwatte, seems like good way to help control temperatures of the alternators, an fuel use.

[Tommy_T]

With all the failures I've encountered with the mowing deck it should not surprise me that
I failed to get a warm & fuzzy feeling with the gas engine mounted internally on the mule.

the first problem I encountered was the 3.5hp was too small, while it worked good with the
batteries charged, if started when the batteries are discharged the engine would stall from the
alternators load. I replaced the 3.5hp engine with a 6hp that could deal with the load.

while controlling the temperature was doable, controlling the noise was not.
so I had to step back.
I removed the engine, installed more batteries then removed the front drive wheels(that sucked).
with the front drive wheels I was able to climb the snow banks and dump more snow on top, without
the front wheels(casters in their place) all I can do is spin the back drive wheels at the snow bank.