How to set speed of space platform?

[VCS]

Hi, i`m building my space platform in Space Age DLC, and i need to set constant speed. Now i`m using pumps and combinator, but it`s very unstable. So how to control speed properly?

[meganothing]

I am using the same method as you.

Maybe someone else knows a better way, but the most basic way I can think of to get a specific stable speed would be to let the rockets run at full speed and then add more width to the space ship until it is slowed down to the speed you want.

Probably supplying the rocket fuel with pulse-width-modulation would be the intelligent solution, this should also produce almost constant but selectable speed. But haven't tried that yet

[Tertius]

For a controller, see this thread:
viewtopic.php?f=193&t=118009

tl;dr:
Don't try to control the speed, instead control the fuel supply. The idea in the mentioned thread is to activate a fuel pump with a percentage of the maximum fuel throughput to get a percentage of the maximum speed.
Speed isn't linear to fuel supply, because the thruster efficiency changes according to the fill state of the thruster, but the effect in general is sufficient: more fuel throughput means more speed.

[eugenekay]

There are multiple ways to achieve "Controlled Flow Rate" to the Thrusters:

• You only need to control Fuel OR Oxidizer. There is no need to overcomplicate the system by limiting Both types of fluid. The excess Fluid type is not wasted, it just changes the color of the Flames.
• Turn the Chemical Plants on/off (or add/remove Modules from Beacons) to directly control the Fluid production rate. Make sure to eliminate Buffer Tanks! The thrusters will still collect Fluid if the ship is not moving, which gives a "Burst" of speed when departing a Planet.
• Pulse the Pump on/off for a Number of Ticks, using Combinator clocks. Pumps (of Normal quality) will move up to 1200 Units/s.... which is equal to 20 Units/Tick. This is the most popular method, but you have to use Circuits extensively (or a pre-existing Blueprint).
• Use smaller Groups of Thrusters - 1 Pump can supply up to 10 Thrusters at full speed, or you can have only 1 or 2 per Group. This lets you turn them on/off in "Banks", rather than trying to throttle Flow Rate across the entire ship at once. I think this is the Simplest method, if not the most Efficient.

Good Luck!

[mrkev]

Hi, i`m building my space platform in Space Age DLC, and i need to set constant speed. Now i`m using pumps and combinator, but it`s very unstable. So how to control speed properly?

Do You really "need to" set a constant speed? I did that at the beginning, but later realized, that I don't actually need constant speed, just slowing down on certain trips is fine. One of the most simple options is to switch off motors. You can do something as simple as this:

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Direct control of the entire fuel suply doesn't work really well, because there is a huge delay, it will take few secons to increase the velocity after you switch on the fuel pump. You could try a Pulse-width modulation, it's a bit advanced to set up, if you want to tie it directly to the velocity, but you can just set a constant number:

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[Tertius]

@mrkev I know I'm a nitpicker, but your pulse-width modulation blueprint is accurate only if the maximum pulse width (120) is an integer multiple of the increment (X).
It would be accurate for all values of X, if you use an arithmetic combinator instead of the decider and use the modulo 120 operation (%) to compute the output. If the value wraps around, the remainder is preserved, the counting includes the previous remainder, and the calculation is accurate. Otherwise the last pause before wrapping is truncated.

[mrkev]

@mrkev I know I'm a nitpicker, but your pulse-width modulation blueprint is accurate only if the maximum pulse width (120) is an integer multiple of the increment (X).

Nope. Also, do you use AI to write this stuff?

[Tertius]

You would come across much more sympathetically if you simply explained the mistake I made. Even AI's as me make mistakes, you know.

[mrkev]

You would come across much more sympathetically if you simply explained the mistake I made. Even AI's as me make mistakes, you know.

Lol, I called it. Anyway, for anyone interested, the X in my example isn't the increment, it's the treshold. I am using the decider for clock generation, it provides ramp-up signal from 0 to 200. The pump is on when clock is below the treshold value. Important thing to notice is that this is modulating the pump output, not the engine input. So setting X to 100 means 50% of pump's output, which is 600/s for a normal pump. That can still feed 5 normal engines. Also, the relation between fuel intake and trust isn't linear, so low values will have bigger effect than large ones (changing X from 2 to 3 is a huge difference, but changing it from 45 to 50 not as much).

[Tertius]

Yes, I didn't look thoroughly enough and assumed you do the approach in the thread I linked with counting in steps so you pulse the pump and increase the amount of pulses instead of creating one pulse with variable length. Sorry. This is my bane: I look too quick and overlook some small but crucial thing.