69 replies to this topic

[Nightbird]

Dimento Graven, on 24 January 2020 - 07:36 AM, said:

Right, but energy has to be applied to spin the gyros up initially, and there has to be some methodology of keeping them spinning once spun up, because after all, 'close to zero friction' is not 'zero friction', so obviously they have to be fed energy once they slow down enough.

So again, according to BattleTech lore, gyros are more or less constantly being fed energy to keep them 'spun up' for usage.

It's why gryo hits were tracked, and part of the reason why getting too hot would affect movement, and why piloting skill rolls would get hit with modifiers and such.

Again, maybe not in our 'current' reality and implementation of gyros is this possible, but hell... 30 years ago when BattleTech was being dreamed up, a lot of the stuff the lore is based on wasn't 'real', yet now, now we have our militaries equipping offensive laser and magnetic rail guns on planes and ships, we have electro responsive materials that are not too far off from being actual 'myomer cables', and the like.

Was commenting on the stream how back in the 30's the "two-way radio wrist watch" of the **** Tracy comic strip was a total "********" unrealistic SCI-FI concept, and now we have smart watches that do THAT VERY THING, and an F-ton more.

In this particular case, the lore allows for it and it's not too stupidly reality breaking for me to accept.

I don't think you're reading what I'm writing. I'm saying even if gyro can be spun up without limit, there is still a momentary limit in preventing a fall when you grip the flywheel to stop the fall. This will reduce the spin to zero damned quickly, and no you cannot spin it up while gripping it.

Nothing here contradicts what you wrote, it's just a limitation on its usage.

Oh s**t, I'm going to fall - gyro stops fall, and you rock back on your feet - Yes
Leaning forward ala Titanic - gyro stops fall momentarily, then runs out of energy - then you fall

Edited by Nightbird, 24 January 2020 - 07:42 AM.

[Akhri Mala]

@op :

Nice try, but you're not going to trick me into exercising.

[Prototelis]

Gyros were very real in the 80s. Gyros that report accurate results even when being subject to extreme amounts of shock have been employed in aircraft instruments since the 1920s.


(If mechs were real they wouldn't exclusively use gyros for balance either. Analog tilt sensing, has also likewise been around for a very long time. Applying a "they wouldn't know because muh 80s" to the worst parts of handwavium because the original writing is so lazy doesn't help.)

Edited by Prototelis, 24 January 2020 - 11:31 AM.

[Dimento Graven]

Prototelis, on 24 January 2020 - 11:23 AM, said:

Gyros were very real in the 80s. Gyros that report accurate results even when being subject to extreme amounts of shock have been employed in aircraft instruments since the 1920s.

Oh yeah sure, but I'm thinking giant 3 ton gyros built for keeping giant bipedal robots upright.

Not sure we have any gyro tech along those lines yet (not like I'm keeping abreast of gyro technology).

[Nightbird]

Dimento Graven, on 24 January 2020 - 11:31 AM, said:

Oh yeah sure, but I'm thinking giant 3 ton gyros built for keeping giant bipedal robots upright.

Not sure we have any gyro tech along those lines yet (not like I'm keeping abreast of gyro technology).

https://www.youtube....ature=emb_title

(a BT gyro would not work like this though)

[Prototelis]

Dimento Graven, on 24 January 2020 - 11:31 AM, said:

Oh yeah sure, but I'm thinking giant 3 ton gyros built for keeping giant bipedal robots upright.

Hah. Yes.

Since the 19th century. Used to stabilize very large boats. I think you need about 5% rotor weight to counteract typical roll forces, and I know larger anti-roll gyros used around WWI weighed in at about 20-25 tons.

[Dimento Graven]

Prototelis, on 24 January 2020 - 11:38 AM, said:

Hah. Yes.

Since the 19th century. Used to stabilize very large boats. I think you need about 5% rotor weight to counteract typical roll forces, and I know larger anti-roll gyros used around WWI weighed in at about 20-25 tons.

Really? Cool!

Didn't know that...

[Prototelis]

They fell out of favor because there are lighter, cheaper, and in some cases better ways to keep something heavy from rolling over in the ocean.

[PhoenixFire55]

Nightbird, on 24 January 2020 - 07:19 AM, said:

Yes and No.

Yes, Gyros are cool. No, Gyros cannot be used to maintain a greater pitch.

Gyros can momentarily be used to prevent a fall by gripping a fast spinning flywheel and feeding off it to give force in the opposite direction to the fall. That moment can be used for the mech's other systems to reorient the mech to a position of balance. However, to maintain a pitch, you will have to be constantly offsetting gravity. After 1 to 3 seconds, the flywheel will stop spinning and you'll fall.

Mech gyros compensate any kind of angular momentum destabilizing the mech. Since weapons aren't located in the center mass, moving a torso around in any direction be it yaw or pitch creates exactly that - excess angular momentum, which is compensated by gyros. Hence there is no difference in stability between mechs that have their weapons located differently.

Stationary center mass offset is compensated by myomers, that work in exactly the same way as your muscles when you hold your dumbbells. The energy required to maintain balance will be different between mechs with different weapon placement, same as the effort required on your part depending on how you hold your dumbbells. However, there is no indication in any of the BT lore that there are situations where required energy can not be supplied. In fact myomers are capable of operating under stress far exceeding values produced by mechs. Thus there is once again no difference in pitch/yaw angles between mechs.

That might go against actual physics, but thats how things work in BT.

[Nightbird]

PhoenixFire55, on 24 January 2020 - 01:28 PM, said:

Mech gyros compensate any kind of angular momentum destabilizing the mech. Since weapons aren't located in the center mass, moving a torso around in any direction be it yaw or pitch creates exactly that - excess angular momentum, which is compensated by gyros. Hence there is no difference in stability between mechs that have their weapons located differently.

Stationary center mass offset is compensated by myomers, that work in exactly the same way as your muscles when you hold your dumbbells. The energy required to maintain balance will be different between mechs with different weapon placement, same as the effort required on your part depending on how you hold your dumbbells. However, there is no indication in any of the BT lore that there are situations where required energy can not be supplied. In fact myomers are capable of operating under stress far exceeding values produced by mechs. Thus there is once again no difference in pitch/yaw angles between mechs.

That might go against actual physics, but thats how things work in BT.

What you haven't answered is time the gyro can maintain that. If said gyro is infinite, then mechs would be able to walk up buildings from the side. A more reasonable estimate is that a hit capable of knocking a mech over can be compensated, no more. While the gyro is compensating, some sort of brake is being applied to the gyro to slow it down, this is where the stabilizing force is coming from. The limit comes from the time it takes for the flywheel in the gyro to reach a stop.

I haven't disagreed with you at all on what the gyro can do, you've only not applied a limit to that ability.

Edited by Nightbird, 24 January 2020 - 01:36 PM.

[PhoenixFire55]

Nightbird, on 24 January 2020 - 01:32 PM, said:

What you haven't answered is time the gyro can maintain that. If said gyro is infinite, then mechs would be able to walk up buildings from the side. A more reasonable estimate is that a hit capable of knocking a mech over can be compensated, no more. While the gyro is compensating, some sort of brake is being applied to the gyro to slow it down, this is where the stabilizing force is coming from. The limit comes from the time it takes for the flywheel in the gyro to reach a stop.

I haven't disagreed with you at all on what the gyro can do, you've only not applied a limit to that ability.

Maintain what? ... Again, gyro compensates excess angular momentum occuring when you start/stop rotating/pitching the torso. That happens near instantly. When torso is in the process of rotating/pitching with a constant angular speed there is no excess momentum generated.

The effects of static imbalance that occurs when you "bend" and stay bended, i.e. pitch, are compensated by myomers, that prevent the mech from toppling over in the exact same way your muscles prevent you from falling over. Except myomers are several orders of magnitude stronger in relation to the stresses mechs create than your muscles in relation to what your body does, thus unlike humans they can "hold" any degree of pitch angle, as long as they get the power supply they need. That power supply comes from the engine, and according to lore is sufficient for anything. That power isn't infinite as engines need refueling, but refueling happens on the timescale of years.

[Nightbird]

PhoenixFire55, on 24 January 2020 - 02:25 PM, said:

Maintain what? ... Again, gyro compensates excess angular momentum occuring when you start/stop rotating/pitching the torso. That happens near instantly. When torso is in the process of rotating/pitching with a constant angular speed there is no excess momentum generated.

The effects of static imbalance that occurs when you "bend" and stay bended, i.e. pitch, are compensated by myomers, that prevent the mech from toppling over in the exact same way your muscles prevent you from falling over. Except myomers are several orders of magnitude stronger in relation to the stresses mechs create than your muscles in relation to what your body does, thus unlike humans they can "hold" any degree of pitch angle, as long as they get the power supply they need. That power supply comes from the engine, and according to lore is sufficient for anything. That power isn't infinite as engines need refueling, but refueling happens on the timescale of years.

I think we're talking past each other because there are different types of gyroscopes.

The ones currently in existence for ships would never be used for mechs because 1) it only has a gradual amount of stabilizing force, it cannot instantly right a fallen mech nor cancel out the energy from being hit with a big AC20 explosive round 2) it is detrimental to the handling of a mech as it is always active and trying to resist pitch and turn even when you want to do those things.

The gyroscope used for mechs is almost certainly of the type with "two joined flywheels spinning synchronously in opposite directions" because "They would have a total angular momentum of zero and no gyroscopic effect." (https://en.wikipedia..._energy_storage). Why? So when a mech is moving normally, a gyro of this type will not actively hinder movement, evasion, etc. If there is 0 net torque, how does this gyro help a mech stand up? Because by suddenly 'gripping' a rapiding spinning flywheel, you can turn all that angular momentum into an explosive amount of torque (https://www.computer...370/13rRUx0geq5) that can offset the impact from an AC20 or stand a mech up from prone (no pushing up with arms) like magic.

Edited by Nightbird, 24 January 2020 - 03:12 PM.

[LordNothing]

Dimento Graven, on 24 January 2020 - 06:01 AM, said:

In my observations it's not actually "instantaneous", it's just very, VERY fast.

But opinions vary I guess...

its likely within one or two server ticks. but large scale actuators tend to be slow simply because of the mass they have to move. so in a physics++ mechwarrior, your arm actuator performance would depend on the amount of tonnage installed in said arm. so a small laser would converge a hell of a lot faster than a gauss rifle.

[BenMillard]

Let's not do real physics in fictional robot combat.

Shoot-and-twist designs like the Centurion and Dragon would physically be terrible at what they are great at.

Indeed, it's a wonder the Dragon can steer left at any speed with 3uAC2 hanging way to the outside like that.

AC20 Hunchback would be terrible at corner peeking with the accel/decel of such a high and heavy ballistic. Twisting a Hunchie would be easier than twisting a Centurion - a design optimised for twist play!

The more humanoid movement from the novels could be taken to extremes. Transformers style, where a humanoid design with shoulder mounts could kneel down and support itself with the arms to peek over and down from a platform.

EDIT: Ridge peeking/hill-humping would be bad in mechs with high mounts due to the slower accel/decel.

There is something to be said for certain chassis being optimised for certain applications. Myomer layout, pivot locations and distribution of larger items such as the engine within the chassis could fine-tune their capabilities.

But the fundamentals of mass and balance can't be denied. Unless it's fiction. Which this is.

Edited by BenMillard, 24 January 2020 - 04:20 PM.

[LordNothing]

Prototelis, on 24 January 2020 - 11:23 AM, said:

Gyros were very real in the 80s. Gyros that report accurate results even when being subject to extreme amounts of shock have been employed in aircraft instruments since the 1920s.


(If mechs were real they wouldn't exclusively use gyros for balance either. Analog tilt sensing, has also likewise been around for a very long time. Applying a "they wouldn't know because muh 80s" to the worst parts of handwavium because the original writing is so lazy doesn't help.)

they use gyros in space craft all the time (reaction wheels or cmgs). its known tech. and no reason they wouldn't work in a bipedal robot. you also use sensory gyros (good examples are the attitude indicators in aircraft or the mems gyro in most phones now), which measure changes in angular velocity, as an input and your reaction wheel/cmg providing corrective measures in a control loop. all known tech. people have even built robots on the concept.

[Nightbird]

LordNothing, on 24 January 2020 - 03:31 PM, said:

they use gyros in space craft all the time (reaction wheels or cmgs). its known tech. and no reason they wouldn't work in a bipedal robot. you also use sensory gyros (good examples are the attitude indicators in aircraft or the mems gyro in most phones now), which measure changes in angular velocity, as an input and your reaction wheel/cmg providing corrective measures in a control loop. all known tech. people have even built robots on the concept.

Great video, it shows the braking "gripping the flywheel" I was talking about. This is the only force that would have effect on a external and much larger body like a mech. The resisting all disturbances feature of this design would reduce the agility of a mech, but this can be mitigated with two joined flywheels spinning synchronously in opposite directions.

You can even see the flywheel coming to a stop after popping the cube up. This is the limit when all the spin was turned into torque.

Edited by Nightbird, 24 January 2020 - 04:08 PM.

[PhoenixFire55]

Nightbird, on 24 January 2020 - 03:09 PM, said:

I think we're talking past each other because there are different types of gyroscopes.

The ones currently in existence for ships would never be used for mechs because 1) it only has a gradual amount of stabilizing force, it cannot instantly right a fallen mech nor cancel out the energy from being hit with a big AC20 explosive round 2) it is detrimental to the handling of a mech as it is always active and trying to resist pitch and turn even when you want to do those things.

The gyroscope used for mechs is almost certainly of the type with "two joined flywheels spinning synchronously in opposite directions" because "They would have a total angular momentum of zero and no gyroscopic effect." (https://en.wikipedia..._energy_storage). Why? So when a mech is moving normally, a gyro of this type will not actively hinder movement, evasion, etc. If there is 0 net torque, how does this gyro help a mech stand up? Because by suddenly 'gripping' a rapiding spinning flywheel, you can turn all that angular momentum into an explosive amount of torque (https://www.computer...370/13rRUx0geq5) that can offset the impact from an AC20 or stand a mech up from prone (no pushing up with arms) like magic.

Dude. This literally has nothing to do with what I've told you twice already. It doesn't matter what type of gyroscope there is, I've clearly stated what BT gyros do - compensate for any kind of excess angular momentum. That leads to any and all types of weapon placement not affecting a mech in any way when torso angular acceleration happens. How they do it is irrelevant. And when there is no acceleration and just static offset of the mech center of mass, i.e. static pitch angle, gyros aren't doing anything. The balance is kept by myomers, again irrespective of weapon placement. Hence weapon placement does not affect mech stability/agility in any way.

[Nightbird]

PhoenixFire55, on 24 January 2020 - 03:45 PM, said:

Dude. This literally has nothing to do with what I've told you twice already. It doesn't matter what type of gyroscope there is, I've clearly stated what BT gyros do - compensate for any kind of excess angular momentum. That leads to any and all types of weapon placement not affecting a mech in any way when torso angular acceleration happens. How they do it is irrelevant. And when there is no acceleration and just static offset of the mech center of mass, i.e. static pitch angle, gyros aren't doing anything. The balance is kept by myomers, again irrespective of weapon placement. Hence weapon placement does not affect mech stability/agility in any way.

Any is not the same as infinite. A gyro that can stand a mech up from prone would not be able to hold an increased pitch that a mech's center of mass does not allow. An infinite gyro would allow mechs to run vertically, obvious this does not happen.

I take any to mean from any direction, within reasonable limits, as this is the only interpretation that makes sense.

[LordNothing]

Nightbird, on 24 January 2020 - 03:39 PM, said:

Great video, it shows the braking "gripping the flywheel" I was talking about. This is the only force that would have effect on a external and much larger body like a mech. The resisting all disturbances feature of this design would reduce the agility of a mech, but this can be mitigated with two joined flywheels spinning synchronously in opposite directions.

you are going to have a lot of control loops working in concert to get the desired movement out of the battlemech. you are going to need a high level computer to control the whole shebang. the individual components like the gyro and each myomer bundle is likely going to need its own local control loop just to control that thing, with the master computer controlling the set points. it also has to make sure all the actuators do the right thing at the right time to stay in sync.

when your mech is standing on its left leg the whole thing wants to roll to the right, and the gyro would need to provide a counter torque to keep the mech upright in that axis. then when you are on the right leg the opposite happens, and you have it oscillate back and fourth through each stride. changes in throttle setting or torso pitch are going to want to topple the mech on the pitch axis, and the gyro needs to compensate for that too. and all this is occuring while controlling the position of each joint on the mech. and everything has to sync up too. the complexity of such a system is enough to make kalman filtering look like first grade arithmetic. and thats before you start shooting it with gauss rounds (the computer likely uses the sensor data to detect incoming projectiles and compensate for their impact before they happen).

Edited by LordNothing, 24 January 2020 - 04:14 PM.

[Nightbird]

LordNothing, on 24 January 2020 - 04:11 PM, said:

the complexity of such a system is enough to make kalman filtering look like first grade arithmetic.

Yet is not more than what each of our brains does every day