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New Product: The Thruster Commander!


(Rusty) #1

Originally published at: https://www.bluerobotics.com/new-product-thruster-commander/

We’re excited to announce a new product today: the Thruster Commander! The Thruster Commander is a small control unit and accessories to make it as easy as possible to start using our thrusters. It’s the perfect test tool in the shop to get them up and running but it also has the capability to control multiple thrusters on a kayak, standup paddleboard, or just about any project you might have in mind!

Check out the new product video for a detailed explanation and to see it in action!

In addition to the control unit, the Thruster Commander includes two potentiometers and knobs that are used for input. There are two output channels and they can be controlled independently or they can be mixed together to provide smooth speed and steering control. Check out the new product video below for more information!

That's all for today. Be sure to visit our stands at Underwater Intervention in New Orleans from February 6-8 and at Oceanology International 2018 in London on March 13-15!


(Mark Langille) #2

Great idea. Will replace the arduino setup I had for our kayak controller.
Assume it handles ramping up and down smoothly for speed control so there are no harsh changes on input?


(Daniel Heideman) #3

Yes, changes in PWM output are limited so that it takes about a second before the PWM signal reaches full speed. While this limits wear on the motors, they’ll still give a bit of a kick when you’re starting off.


#4

Very nice device!

Does the Thruster Commander have some kind of lov voltage alarm or cut off, to prevent running the battery too low?


(Rusty) #5

Hi @Mikxie - It doesn’t have that, unfortunately, but that’s a great idea! There aren’t any free inputs on the microcontroller used on the Thruster Commander so we’d have to make some more substantial changes to add this.

I would recommend using a simple lipo battery alarm.


(Philip Krug) #6

Do the pots have a center detent? I am guessing the value of the pot is around 10k ohms.
Thanks
Phil


(Jonathan) #7

Phil,

The pots do have a center detent.

Best,

Jonathan


(Daniel Heideman) #8

The pots are 10 kohm.

Due to a quirk with the pot detection circuit, higher-value pots are not recommended as they will not output the correct PWM signal when centered.


(Philip Krug) #9

I have a bunch of 5k center detent pots that should work.
Thoughts?
Thanks
Phil


(Mark Langille) #10

Are there any details and phots on the controller you guys used in the demo in the video? Just curious how it was setup?


(Daniel Heideman) #11

5 kohm center detent pots should work just fine.

However I would double check that any replacement pots give a “stop” PWM output (i.e. the thrusters don’t turn) when the pot is at its center detent before using them on a project.


(undersearobotics.com) #12

Cool product and very cool project. I’d love to learn more about your waterproof hand controller. How did you waterproof the potentiometers?


(Daniel Heideman) #13

Here are some pictures of the setup we used for the SUP in the demo:

Inside of case, top:

Inside of case, bottom:

Outside of case:

Hand controller:

The wiring for the Thruster Commander board is set up the same way as shown in the documentation, just with the steering pot and a deadman switch mounted on the hand controller.

The deadman switch is one of our switches which has been modified to be a momentary switch, disabling the motors when released. The potentiometer is just one of the 10 kohm center-detent pots that come with the Thruster Commander. We found these pots to work sufficiently well for a short period of time after being submersed in saltwater, so we didn’t bother waterproofing it for the demo.


(Philip Krug) #14

Received my Thruster Commander yesterday.

I am very happy with this unit. It works perfectly and I can’t wait to get it finished up so I can do some testing on the water.

Here is a quick video I threw together of my initial bench testing of Thruster Commander. The video is pretty crude but it hopefully conveys what I did.


(Mark Langille) #15

Any chance you might share the stl for the handheld control?


(Daniel Heideman) #16

The model of the hand controller was made in Onshape and can be found here. Feel free to copy and modify it to fit your project.

There are a few issues we would like to fix in this hand controller before we take the board out again, such as replacing the momentary switch with a toggle switch for start/stop/direction control and a boat kill switch/lanyard to stop the motors if you fall off. As it currently is, holding the paddle and the controller at the same time is cumbersome and the deadman switch is not particularly easy to hold down for long periods of time.


(Philip Krug) #17

Output waveforms for Mixed Input. Same as above minus the smoke :wink:

I am trying to figure out a way to plot this all on “paper”.
Any suggestions would be greatly appreciated.

The maximum forward and reverse thrust performance numbers for the T200 are different. "At 12VDC the maximum forward thrust = 7.8 lbf and the maximum reverse thrust = 6.6 lbf.”

I am guessing the Thrust Commander has an algorithm that takes this difference into account so when the speed control is set to center zero and the steering control is operated, the thruster performance is matched and will be held to a maximum of the reverse thrust performance. I think this is what I am seeing on the scope. This would make sense to me if keeping one’s craft in place while turning is a desired outcome.

Turning/spinning in place - This is an old video I made a while back. The Thruster Commander was not available. I was controlling the thrusters with a Pololu Micro Maestro 6-Channel USB Servo Controller and a couple of linear potentiometers. Basically the same mode as the Thruster Commander’s Dual Input mode.

Phil


(Daniel Heideman) #18

The Mixed Input algorithm is actually pretty simple; it looks something like this:

left_output  = speed_input + steering_input;
right_output = speed_input - steering_input;

speed_input is mapped to 1000~2000 μs, and
steering_input is mapped to -400 to 400 μs

The left and right outputs are constrained between 1000 and 2000 μs. This is why when speed_input is large (near 1000 μs or 2000 μs), even if you turn the steering input all the way to the max, one thruster will slow down but the other will not noticeably speed up (because it is already maxed out).


(Philip Krug) #19

Hello, the M3X0.5 mounting holes are not the same depth.

I discovered this when I tried to mount the Thruster Commander on a cast chassis box cover which is 1.90 mm thick. My hardware on hand is pretty limited and the shortest M3X0.5 screw is a button head with a 6 mm length. Works in the deep thread hole but not in the other one. The screw is about 1 mm too long.

Switching to flat head screws and will order something close to a 3 mm thread length.

Phil


(Philip Krug) #20

“We found these pots to work sufficiently well for a short period of time after being submersed in saltwater, so we didn’t bother waterproofing it for the demo.”

That sentence caught my eye, especially the “… sufficiently well for a short period of time…” part :wink:

Bottom line is if water does intrude the controller housing bad things will happen and especially if it is salt water.

Over the years I have struggled with keeping water out of my controller boxes. Most of the designs I have come up with include the controller board in the controller boxes. Now with the launch of the Thruster Commander, I decided to revisit the issue of water getting in my controller boxes.

I came up with a simple idea of using cable glands to provide some measure of protection for the potentiometer shaft couplings. It works very well. I did some simple tests, one was to spray water on the controller box and the other was to submerge the controller box in a few inches of water. The only place where water entered the controller box was the seal between the lid and the box itself. There is a gasket but was still can intrude, in the spray test and the submersion test.

I have ordered a cast aluminum box from BUD that has an IP68 rating. My original cast aluminum box is a Hammond and has an IP54 rating. IP Codes.

Here is a link to some photos related to my first version controller box setup.

Then I got to thinking about modifying a BlueRobotics switch assembly and use it as my potentiometer shaft coupling.

Here is a link to some photos and a video that hopefully will explain my idea. I think it will work and all my knobs will look the same. Not the cheapest solution but a bit more elegant. :wink:

The first photos should have a written description of what I am trying to accomplish.

I would be great if BlueRobotics offered something like this.

Phil