Baitboat channel mixing

Hi I’m looking for some help with my project to add autopilot to my bait boat.

The boat is an angling technics microcat. It is a catamaran style boat powered by four bilge pumps. Two pump water out the rear of the boat to propel it forward, and two towards the front of the boat for reverse. It it is set up on my transmitter with mixes to steer using one stick as follows

Pushing forward moves the boat forward
Pushing backwards moves the boat backwards
Pushing left turns the boat left by operating the rear right pump forward and the forward left pump in reverse
Pushing right performs the counter to pushing left.

This all works when the two esc’s are connected to the receiver, but when I connect to the pixhawk 6C PMW I/O out only one side operates and not correctly.

I assume I need to make the Pixhawk perform the same mixing that the transmitter / receiver is doing. But I have no clue at all how to do this.

Any help would be appreciated.

Ok so I’m not getting anywhere with this and close to abandoning the project which is frustrating.

I can create a mix on the transmitter to control the four pumps in the correct way from 1 stick on the transmitter. But this would be useless for auto pilot to the spots I have marked in carp pilot.

I need to recreate the same mix on the pixhawk 6c as I have on the transmitter.

There are two esc’s both viper marine 15. Each esc is connected to two bilge pumps for propulsion.

One pump each side pushes the boat forward and the other backwards. So far when plugged into the pixhawk they operate as follows

If I press the stick forward the right reverse pump starts
If I press the stick backwards the right forward pump starts
If I press the stick left the left reverse pump starts
If I press the stick right the left forward pump starts

What I need is

When the stick is pushed forward both left and right forward pumps run
When it is pulled backwards both left and right reverse pumps run
When the stick is pulled left then the left reverse and right forward pumps should run
When the stick is pulled right then the right reverse and the left forward pumps should run.
When the stick is centred all pumps should stop

I just cannot work out how to set the servo outputs to do this and all documentation I have seen is using boats with only two motors that is not helping.

I think this might work, I think I had to do something similar to use separate throttle and brake servos on a car

.
Assuming each motor its own one way esc on its own servo out on the flight controller.

set both left pumps to “left motor” and the right pumps to “right motor”

on servo outputs for the motors
set the servo min to 1000
set servo trim to 1000
set servo max to 2000

and on the rear motors select reverse output so they increase speed with reverse throttle.

you might have to change servo trim to 2000 on the rear motors.

Unfortunately they are not.

There are only two esc’s meaning that each side is on a single esc and both motors on that side are controlled by the same stick movement and on the same pixhawk output servo

How you control with just one ESC two motors, one for forward and one for reverse propulsion?

On the taranis this is achieved with a mix which allows control of the pumps based on a single stick input and it works. See screenshot. The mix is on channel 2 and t3 in this case

Problem is I do not know how to implement this mix with the pixhawk.

I am still not getting your installation.
I understood that you have 2 motors / pumps on each side, one for fwd and one for rev
So in total 4 motors / pumps.
But you only have 2 ESC one on each side.
In all your cases are only max two motors / pumps are working this is correlating with two ESC. But how you select which motor / pump is used in all cases.
Give a short describition about your interconnections between the two ESC and the four motors / pumps or show me my missunderstanding.
The wished behaviour of your system is a kind of skid steering in my eyes

The pumps are connected to the two esc’s using their negative wire one to ve+ one to ve- with their live wires connected to the battery live.

Basically with the mix on the taranis pushing the throttle forward would spin the rear pumps propelling forward.

Pushing the throttle backwards the forward pumps would propel backwards.

Pushing left operates the left reverse pump and the right forward pump. And pushing right the opposite.

If I wire the esc’s direct to the two channels on the receiver this works. If I wire it to the pixhawk it works if I set the channels to pass through. But this won’t work if I try any other configuration.

The original boat worked this way, but never had autopilot.

Well sure, that’s like having no flight controller at all. You need a Frame Type and Class configuration that Ardurover supports. You need an ESC per motor/pump and perhaps Omni-X would work.

So the pixhawk cannot mix channels like a Taranis transmitter does with only 2 ESC’s.

Is my other option then to just use the forward propelling pumps and turn the boat with left on right off etc.

Would this just be a case of setting the two channels to throttle left and right ?

What do you mean with “battery live” and “their live wires”. Is this battery plus? So both motors of one side are connected with one wire to battery plus while the side of the motors are controlled of half brigde of the ESC.
So this is a missuse of the ESC but if it works ok.
So this is really compareable to a system with just one motor for each side which can be controlled forward and reverse. And this is a traditional skid steering.
You can try to set the
servo_output of the left ESC to SERVOl_FUNCTION = 73 (throttle left)
servo_output of the right ESC to SERVOr_FUNCTION = 74 (throttle right)
PILOT_STEER_TYPE = 0

Hi

Thank you for the reply

Each side of the boat has two pumps the pumps positive wires are wired into the boats positive feed from the battery.

The negative wire for each pump are wired into the esc’s ve+ and ve- leads.

The pumps are rule bilge pumps so they only spin one way. The boat is powered forward by the two rear pumps in the catamaran hull as the outflow points towards the stern of the boat. The forward pumps have the outflow pointing towards the bow of the boat.

This is how the boat has always been wired from the manufacturer. I just replaced the existing esc’s with some viper marine 15 ones.

At present channel 1 in the pixhawk is left side esc and channel 4 the right side. These correspond to the throttle and rudder outputs on my mode 2 Taranis transmitter.

I will try see if I can get your configuration to work.

I tried this setup and here’s the outcome.

Servo output 1 set to throttle left
Servo output 2 disabled
Servo output 3 disabled
Servo output 4 set to throttle right.

If I push the left hand stick up both forward engines run
If I push it down both forward engines stop

But here’s now the interesting thing

If I push the right hand stick up then it operates the left reverse and right forward pumps to steer left

If I push it down it operates the right and left forward pump to steer right.

This is exactly what I am trying to achieve but I was trying to do it on one stick. But I can cope with that.

Question now is what will it do on a mission, will it steer as steering is on the right stick and these servos are disabled in the servo output or will it just go forward based on the left stick operation?

This is what PILOT_STEER_TYPE,0 is for. The most common stick control does use only one stick if configured properly. UP/Down for forward/reverse, Left/Right for steering on 1 stick. I don’t do Rover that way but most do.
So, you are close.
Steering Input Type Read the Note

I have PILOT_STEER_TYPE set to 0.

I have recalibrated with the throttle stick centred for off position.

Now I have the following

Push left stick forward both forward motors run
Push the left stick back both rear motors run

Push the right stick forward boat will turn left as left reverse and right forward run
Push the right stick back boat will turn right as right reverse and left forward run

This essentially is how I need it to work and I can live with the two stick operation

But will it perform the right stick operations during auto pilot mode to reach a destination given in the servo page those sticks are set to disabled.

Which stick do you want to use? Mode 2 radio? For Rover Throttle is Throttle and Steering is Roll. Use the RCMAP parameters to assign how you want to control it.

This is showing Throttle forward and a Right turn. Pitch and Yaw do nothing.

My radio is mode 2

The left throttle input on the transmitter is roll and yaw together in the radio calibration screen but is operating the forward and reverse pumps correctly.

The right elevator input on the transmitter is operating throttle in the radio calibration screen but is operating front and reverse pumps correctly for steering

This is my servo output configuration

Essentially the sticks work albeit a little mixed up.

Do you have a mix on the radio? If so get rid of it. Then, using the Radio Calibration screen for reference configure the RCMAP until the left stick throttle moves the throttle bar only and the left stick yaw (left/right) moves the Roll bar only. The right stick should do nothing to drive the craft if configured this way. It’s the most common configuration. Well, you could configure the Right Stick instead if you wanted to for some reason, up to you.

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