Future Helicopter Control Systems
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Future Helicopter Control Systems
I was intrigued hearing that the Commanche uses a twist grip on the cyclic rather than the pedals for yaw control.
My internet friend Dave Jackson is biased towards the synchromeshing side by side MR configuration; mostly it seems for control simplicity reasons.
I think that the future of control simplicity in civilian helicopters lies in FBW systems that are orders of magnitude cheaper due to technological advances, and mass production cost savings.
I wonder if the current developement of high voltage electrical systems for automotive applications might be applicable for light helicopters.. . . .Mainly for weight, noise and parts count reasons, currently being introduced in cars are 48 volt all electric power steering and all electric braking. Soon hydraulic pumps on cars will be old school, does anyone think that this will the case on light helicopters?
Automotive starters and alternators will are being combined into the flywheel, I think power will be on the order of 400-500 amps in order to drive formerly mechanical or hydraulic systems like air pumps or power steering
I'm interested in what people think future helicopter control systems will look like, both from what the control forms will be (pedals, sticks, joysticks?), and the technology behind them.
My internet friend Dave Jackson is biased towards the synchromeshing side by side MR configuration; mostly it seems for control simplicity reasons.
I think that the future of control simplicity in civilian helicopters lies in FBW systems that are orders of magnitude cheaper due to technological advances, and mass production cost savings.
I wonder if the current developement of high voltage electrical systems for automotive applications might be applicable for light helicopters.. . . .Mainly for weight, noise and parts count reasons, currently being introduced in cars are 48 volt all electric power steering and all electric braking. Soon hydraulic pumps on cars will be old school, does anyone think that this will the case on light helicopters?
Automotive starters and alternators will are being combined into the flywheel, I think power will be on the order of 400-500 amps in order to drive formerly mechanical or hydraulic systems like air pumps or power steering
I'm interested in what people think future helicopter control systems will look like, both from what the control forms will be (pedals, sticks, joysticks?), and the technology behind them.
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Hans,. .You are right to ask both questions, because most observers think only of the shape and placement of the stick, which is the least important issue. The control schemes behind the stick are the essence of modern flight controls, the sticks are merely electrical joysticks.
The advanced control laws in Comanche are a case in point. The aircraft has velocity and position stabilization, so the pilot does not juggle attitude to fly, he directly commands either ground speed/direction or position, and the computer controls make the aircraft do as he commands. There is automatic altitude hold, and automatic turn coordination down to speeds of 10 knots, so low speed maneuvers are done with the fingers of one hand, while the pilot can look at tactical information or set up weapons and sensors.
There is even a mode where the fire control computer takes over, and points the weapons while the pilot monitors the situation.
Future systems like this will rely on standard computer chips (remember when digital watches were $400? They now come in cereal boxes!) and will replace the heavier and more expensive control linkages and servos currently being used, at least on helicopters above perhaps 4000 pounds or so.
The electrical systems will make use of higher voltages to reduce weight. Since power is proportional to volts squared, smaller lighter electrical lines can do the work more easily. Comanche has a 270 volt DC primary electrical power system!
The advanced control laws in Comanche are a case in point. The aircraft has velocity and position stabilization, so the pilot does not juggle attitude to fly, he directly commands either ground speed/direction or position, and the computer controls make the aircraft do as he commands. There is automatic altitude hold, and automatic turn coordination down to speeds of 10 knots, so low speed maneuvers are done with the fingers of one hand, while the pilot can look at tactical information or set up weapons and sensors.
There is even a mode where the fire control computer takes over, and points the weapons while the pilot monitors the situation.
Future systems like this will rely on standard computer chips (remember when digital watches were $400? They now come in cereal boxes!) and will replace the heavier and more expensive control linkages and servos currently being used, at least on helicopters above perhaps 4000 pounds or so.
The electrical systems will make use of higher voltages to reduce weight. Since power is proportional to volts squared, smaller lighter electrical lines can do the work more easily. Comanche has a 270 volt DC primary electrical power system!
Nick,
Every time I read 'control laws', something cold runs up my spine! Are they set in concrete, or are they flexible enough to allow a pilot to put a bit of 'dutch' into the demand, and do something that will skew the helicopter the way he wants it to go? I know that I often demand my machine to get out of balance, skid, slide or drift, especially when a film job needs that little bit different to get the shot. Does FBW allow this, or will we become a slave to those "control laws" ?
Every time I read 'control laws', something cold runs up my spine! Are they set in concrete, or are they flexible enough to allow a pilot to put a bit of 'dutch' into the demand, and do something that will skew the helicopter the way he wants it to go? I know that I often demand my machine to get out of balance, skid, slide or drift, especially when a film job needs that little bit different to get the shot. Does FBW allow this, or will we become a slave to those "control laws" ?
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It's possible to allow for overriding FBW, as long as the control is actually there and the aerodynamics permit manual flight.
My guess is, well, future designs will close those options out. Ugh.
My guess is, well, future designs will close those options out. Ugh.
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Nick;
I have a question. Will your FBW system allow the pilot to set a 'neutral' postion for the yaw control?
I am 6'5" and a naturally comfortable position for my right forearm is about 40 degrees off the centreline; so for some cyclics my wrist is 'cranked' about 30 degrees. For more 'normal' <img src="smile.gif" border="0"> pilots, say 5'10', the forearm would probably be about 10 degrees of the centre line.
If one will have to twist one's wrist from this position it would make life a lot easier if one could at least start from a comfortable neutral position.
On a slightly different topic; about 12 years ago, I did a gig with an aerospace PhD candidate who had done some helicopter FBW work. It involved flying from the flight engineer's seat in a heavily modified DC-8 simulator. He was interested in; "What would you do if this or that failed, and how could his software compensate for a failure - neat stuff. . . <img src="cool.gif" border="0">
I have a question. Will your FBW system allow the pilot to set a 'neutral' postion for the yaw control?
I am 6'5" and a naturally comfortable position for my right forearm is about 40 degrees off the centreline; so for some cyclics my wrist is 'cranked' about 30 degrees. For more 'normal' <img src="smile.gif" border="0"> pilots, say 5'10', the forearm would probably be about 10 degrees of the centre line.
If one will have to twist one's wrist from this position it would make life a lot easier if one could at least start from a comfortable neutral position.
On a slightly different topic; about 12 years ago, I did a gig with an aerospace PhD candidate who had done some helicopter FBW work. It involved flying from the flight engineer's seat in a heavily modified DC-8 simulator. He was interested in; "What would you do if this or that failed, and how could his software compensate for a failure - neat stuff. . . <img src="cool.gif" border="0">
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John and Chips,. .Save the cold chills for mid-December when its might hot!
The control laws do not add or subtract from the aerodynamic capability of the basic helicopter, so they won't let an LTE prone yaw system off the hook, and they won't stop you from flying out of trim, if that's what you command.
The control laws are actually like using Windows as the operating system for your PC. Old fashioned machine language is faster, uses less code, and is more prone to inexplicable software coding errors (until the code is run a bunch and de-bugged).
Windows runs as wysiwyg, so you know exactly what you will get, and the human error rate is very much lower. The fact that I'll give $5 to anyone who is on this web site in machine language, and never spend a cent proves which way you all want it!
The advanced laws allow you to command velocity while creeping up to a hoistee, or an oil rig. You do not have to balance attitude to command the acceleration to then judge how much to vary the velocity. If a gust comes by, the controls automatically retrim the attitude to wash it out, while you are looking hard for wires or obstructions. If you get into white-out or brown-out, you simply relax and let the aircraft settle down to zero ground speed while you search for cues (the controls already have their cues from the intertial and GPS sensors, they are not browned-out). The laws work exactly as easily in the darkest night, in the thickest fog and driving rain.
A quick look at our accident statistics shows that we are responsible in the majority of accidents. They call it "pilot error" but it is really due to the fact that the job we have to do is simply not do-able some of the time. Either we settle for the fact that helos must have accident rates 2 or 3 times higher than airplanes, or we do something about it.
As George Carlin says, "They pay me to think up goofy s**t!" Advanced control laws are the next wave because we decided not to settle for the same old crap we were given when that was all that was possible to have. We had the gall to think that maybe the pilot wanted a helicopter that simply did what he commanded, and not what it wanted to do!
[ 24 January 2002: Message edited by: Nick Lappos ]</p>
The control laws do not add or subtract from the aerodynamic capability of the basic helicopter, so they won't let an LTE prone yaw system off the hook, and they won't stop you from flying out of trim, if that's what you command.
The control laws are actually like using Windows as the operating system for your PC. Old fashioned machine language is faster, uses less code, and is more prone to inexplicable software coding errors (until the code is run a bunch and de-bugged).
Windows runs as wysiwyg, so you know exactly what you will get, and the human error rate is very much lower. The fact that I'll give $5 to anyone who is on this web site in machine language, and never spend a cent proves which way you all want it!
The advanced laws allow you to command velocity while creeping up to a hoistee, or an oil rig. You do not have to balance attitude to command the acceleration to then judge how much to vary the velocity. If a gust comes by, the controls automatically retrim the attitude to wash it out, while you are looking hard for wires or obstructions. If you get into white-out or brown-out, you simply relax and let the aircraft settle down to zero ground speed while you search for cues (the controls already have their cues from the intertial and GPS sensors, they are not browned-out). The laws work exactly as easily in the darkest night, in the thickest fog and driving rain.
A quick look at our accident statistics shows that we are responsible in the majority of accidents. They call it "pilot error" but it is really due to the fact that the job we have to do is simply not do-able some of the time. Either we settle for the fact that helos must have accident rates 2 or 3 times higher than airplanes, or we do something about it.
As George Carlin says, "They pay me to think up goofy s**t!" Advanced control laws are the next wave because we decided not to settle for the same old crap we were given when that was all that was possible to have. We had the gall to think that maybe the pilot wanted a helicopter that simply did what he commanded, and not what it wanted to do!
[ 24 January 2002: Message edited by: Nick Lappos ]</p>
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I love the next wave .... 
Sounds like it will be an exciting time to be flying.
I can understand as we move forward, that inputs will tell the system what we want, and the system willl attempt to give it to us, as you describe, especially ina combat situation, you would want to have your eyes outside (or on sensors) as much as possible. The combat rule still applies "he who sees/finds the other first ..."
Nick, I wondered about the feasibility of designing a one handed control for the heli, all that might be needed now is a push/pull "slider" for the cyclic assembly to manage or input collective to the system, was there any thoughts to that type of setup, or did remaining with a electrice collective with switches on it (HOTAS for heli's) remain the best option at this time?
[ 24 January 2002: Message edited by: RW-1 ]</p>
Sounds like it will be an exciting time to be flying.I can understand as we move forward, that inputs will tell the system what we want, and the system willl attempt to give it to us, as you describe, especially ina combat situation, you would want to have your eyes outside (or on sensors) as much as possible. The combat rule still applies "he who sees/finds the other first ..."
Nick, I wondered about the feasibility of designing a one handed control for the heli, all that might be needed now is a push/pull "slider" for the cyclic assembly to manage or input collective to the system, was there any thoughts to that type of setup, or did remaining with a electrice collective with switches on it (HOTAS for heli's) remain the best option at this time?
[ 24 January 2002: Message edited by: RW-1 ]</p>
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Regarding the all in one control, there is a variable stability Bell 205 in Canada with a twist grip yaw control, conventional motion cyclic control and collective control all on one single side mounted joystick inceptor. The collective action is through the raising and lowering of the whole grip assembly.
I recall not liking that (try doing a quickstop!) but having yaw as a twist grip on the sidestick control was very intuitive.
Combine the sidestick controller with a translational rate command through a height hold AFCS and I guess thats what Commanche has for low speed work??
I recall not liking that (try doing a quickstop!) but having yaw as a twist grip on the sidestick control was very intuitive.
Combine the sidestick controller with a translational rate command through a height hold AFCS and I guess thats what Commanche has for low speed work??
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Rigid,
I had heard about that one, and agree on the up down being "too much".
What would you think about a sliding one as I described?
Slide aft slightly to "pull" collective, forward to lower. You wouldn't need a lot of travel if giving the commands to a FBW system.
I had heard about that one, and agree on the up down being "too much".
What would you think about a sliding one as I described?
Slide aft slightly to "pull" collective, forward to lower. You wouldn't need a lot of travel if giving the commands to a FBW system.
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Rigid_rotor and RW-1,. .We use a right hand grip with longitudinal, lateral and yaw, with a collective pitch trimmer (not a full blown collective control, more like a beeper for altitude changes through the altitude hold). We did away with a full collective controller on the right hand for the valid reasons that rigid_rotor notes (Laplace transforms, huh? I find them binding, myself!)
The collective pitch in Comanche is in the left hand, is similar to a short-throw conventional collective, and has a trim feedback so that in altitude hold, it rises and falls to match the power/blade angle of the rotorhead. It is purely electronic, of course. Both the pilot and copilot collectives are mechanically linked, so there is no confusion as to how much collective pitch is applied.
RW-1, your intuitive guess is pretty close!
[ 24 January 2002: Message edited by: Nick Lappos ]</p>
The collective pitch in Comanche is in the left hand, is similar to a short-throw conventional collective, and has a trim feedback so that in altitude hold, it rises and falls to match the power/blade angle of the rotorhead. It is purely electronic, of course. Both the pilot and copilot collectives are mechanically linked, so there is no confusion as to how much collective pitch is applied.
RW-1, your intuitive guess is pretty close!
[ 24 January 2002: Message edited by: Nick Lappos ]</p>
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Hans
You raise an intriguing subject.. . . .No one would question the increasing role that electronics will play in all vehicles. The points that you, Nick and others have mentioned are very interesting, and no one would doubt they are representative of the helicopter's future.
You specifically mentioned my interest in helicopters that are easier to fly, plus the non-electronic direction I am going. The following addresses this specific area only. I hope that it is an objective perspective and not perverted by the depth of my involvement. Any arguments or corrections will be appreciated.. ._____________________
Fly-by-wire is a means of converting the pilot's desire into an action by the helicopter. The helicopter must still have the ability to dynamically enact this action in the most effective means possible. I think that Gareth Padfield mentions in his book "Helicopter Flight Dynamics" something to the effect that fly-by-wire will assist with flight control but it will never be an alternative for dynamic improvements.
The <a href="http://www.unicopter.com/unicopter.html" target="_blank">UniCopter</a> project is an attempt to improve the dynamics, flight-control simplicity and safety of the helicopter by unifying a number of existing features; such as; the intermeshing configuration, Really Rigid Rotors, the Advancing Blade Concept, rotor governor, etc.
Hopefully, the results should be;<ol type="1">[*]Instant response to pilot cyclic inputs, because of RRR[*]Less vibration on the pilot and craft, because of RRR[*]Higher forward speeds, because of ABC[*]The ability to incorporate ABC, because there are two main rotors.[*]Automatic entry into autorotation, because of the rotor governor.[*]Symmetrical handling characteristics. .[/list=a]
Fly-by-wire would only directly address item 6/.
Another consideration is that it may be many years before FBW becomes a contributor to the popularization of rotorcraft. It's limiting aspect, will not be the Central Processing Unit or the software but the high cost of the sensors, the actuators and their ancillary equipment.
[ 25 January 2002: Message edited by: Dave Jackson ]. .To try and improve it.
[ 25 January 2002: Message edited by: Dave Jackson ]</p>
You raise an intriguing subject.. . . .No one would question the increasing role that electronics will play in all vehicles. The points that you, Nick and others have mentioned are very interesting, and no one would doubt they are representative of the helicopter's future.
You specifically mentioned my interest in helicopters that are easier to fly, plus the non-electronic direction I am going. The following addresses this specific area only. I hope that it is an objective perspective and not perverted by the depth of my involvement. Any arguments or corrections will be appreciated.. ._____________________
Fly-by-wire is a means of converting the pilot's desire into an action by the helicopter. The helicopter must still have the ability to dynamically enact this action in the most effective means possible. I think that Gareth Padfield mentions in his book "Helicopter Flight Dynamics" something to the effect that fly-by-wire will assist with flight control but it will never be an alternative for dynamic improvements.
The <a href="http://www.unicopter.com/unicopter.html" target="_blank">UniCopter</a> project is an attempt to improve the dynamics, flight-control simplicity and safety of the helicopter by unifying a number of existing features; such as; the intermeshing configuration, Really Rigid Rotors, the Advancing Blade Concept, rotor governor, etc.
Hopefully, the results should be;<ol type="1">[*]Instant response to pilot cyclic inputs, because of RRR[*]Less vibration on the pilot and craft, because of RRR[*]Higher forward speeds, because of ABC[*]The ability to incorporate ABC, because there are two main rotors.[*]Automatic entry into autorotation, because of the rotor governor.[*]Symmetrical handling characteristics. .[/list=a]
Fly-by-wire would only directly address item 6/.
Another consideration is that it may be many years before FBW becomes a contributor to the popularization of rotorcraft. It's limiting aspect, will not be the Central Processing Unit or the software but the high cost of the sensors, the actuators and their ancillary equipment.
[ 25 January 2002: Message edited by: Dave Jackson ]. .To try and improve it.
[ 25 January 2002: Message edited by: Dave Jackson ]</p>
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Thanks Nick.
If I close my eyes and imagine a one handed control system for a heli, that is what "Feels" right to me. A twist for yaw cyclic, and slide fore/aft for collective.
Let's not get too automated though, or sikorsky will be building large people carrying Cyphers ...
If I close my eyes and imagine a one handed control system for a heli, that is what "Feels" right to me. A twist for yaw cyclic, and slide fore/aft for collective.
Let's not get too automated though, or sikorsky will be building large people carrying Cyphers ...
