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Hi – I am curious to know if anyone has had any experience with machines that use fuzzy logic, as apart from a couple of vague references the subject does not appear to have been discussed in the forums.
As I understand it these appliances rather than have a set of parameters which are fixed for a particular program can adapt them to suit varying conditions. For example in a washing machine the water level, temperature and wash time can be automaticaly revised to suit the dirtiness, size etc of the load.
If anyone has any info on these it would be good to share it on this thread so that we can all be a bit more informed.
For instance does fuzzy logic make fault finding any harder?
What type of transducers are used to measure things like quantity of suds in the M/C or size of load etc
Here is my contribution to get the ball rolling – Fuzzy logic defined.
Fuzzy logic as opposed to binary logic deals with values that cannot be described in absolute terms eg. on/off, true/false logic 1 or 0 etc. Fuzzy logic values can contain elements of both. For instance we might poll UKWG members with a question ‘Do you like your work’. If there were only two option buttons ‘Yes’ or ‘No’ then each member would be forced into a position where they had to commit to ‘yes i do’ or ‘no I don’t’.
In reality however the situation is much more complex than this because each member would have different aspects of the job that he likes and others that he does’nt like. So each member could answer ‘yes’ and ‘no’ to the question and still be telling the truth. This is fuzzy logic. To express a value in fuzzy logic we have to do it as a percentage or ratio i.e. I like my work 80{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} and I don’t like my work 20{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d}.
Fuzzy logic in a control situation works on the principal of constant change to suite varying parameters and is based on a rule like this:-
IF (parameter a) AND (parameter b) THEN (control c).
Suppose you are running a bath. As a human you usually monitor the water temperature by dipping your hand in the water and adjusting the tap accordingly. So:-
IF (the water is too hot) AND (getting hotter) THEN (turn up the cold tap / turn down the hot tap).
IF (the water is too cold) AND (getting colder) THEN (turn up the hot tap / turn down the cold tap).etc
Control systems based on fuzzy logic attempt to mimic this human empirical method rather than the more conventional methods which are based upon comparison using absolute values (eg. a normal washing machine) only they can do it very much faster.
Andy
Re: Fuzzy logic
HI,
Turbidity…the clarity of the water can be measured by “infra red devices”, where light soiling is encountered the wash and rinse times can be reduced.
The load on the motor….measuring the torque of the motor through the current required to lift the load and control with the tacho, allows “weight” to be caluclated in conjunction with the program selected.
Filling to temp, using an NTC device to introduce hot water to allow a warmer filling temp to be achieved. ( this is what causes LG autos to leak from the dispensor), an NTC being faster in operation than a stat.
Just a few explanations, fault finding can be easier using the electronic fault codes. However its still a washer, it still operates to the same fundamentals that they used for years.
KevinRe: Fuzzy logic
It occured to me when I read my previous post in the cold light of day, that I have not made a proper link between my example of the UKWG poll and the control aspect of fuzzy logic (it was in the wee hours).
The results of our poll would at any instant of time be highly subjective depending upon the circumstances prevailing at that moment. For instance – If you have had a bad day, you come home tired and hungry and you answered the poll then you would probably hate the job 90{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d}. If on the other hand you had a brilliant problem free day and your pocket was bulging with cash, the results would be just the opposite.
It is this reaction to circumstances that are continually in a state of flux that forms the basis of fuzzy logic control.
I hope that makes better sense
Andy 🙂
Re: Fuzzy logic
Well Kevin it looks like you and me are the only ones that give a monkeys ship about fuzzy logic. Strange really when you consider that probably every appliance produced in the near future will use it. Having said that, apart from any new types of sensors that are employed I don’t suppose from a repairers point of view it will make much difference.
Before this thread sinks down the list into oblivion I want to mention an application of fuzzy logic which I have contemplated that would deal with a fundamental problem which has had quite a bit of forum space lately. As far as i know this has not been done yet but I might be wrong, no doubt it is on the CAD/CAM somewhere.
This problem is the use/misuse of detergents. At the moment it is left up to the operator of the m/c to administer the correct dosage of detergent prior to the wash cycle. As has been mentioned many times this is a very hit and miss affair which probably rarely results in the correct dosage due to the many different factors involved. (the degree of dirt in the load, amount of detergent used etc).
Using fuzzy logic the operator could be removed completely from this process. Instead of using a conventional soap drawer, a hopper type dispenser could be used which is filled with powder by the operator. Detegent is administered by the microcontroller through means of a valve assy into the m/c.
As the detergent is neutralised by the dirt in the clothing more powder can be gradually added until the optimum dosage for that particular load is achieved. The clothes are washed correctly and there is no wastage as the machine constantly adapts the wash program to the needs of that load.
When the hopper needs refilling a front panel warning light alerts the operator.
The only problem is what type of sensor could be used to sense the detergent / water saturation level. Maybe something that could detect a particular level of a chemical used in the detergent??
Andy 😥 😥
Re: Fuzzy logic
IF>THEN>AND logic is applied to many things Andy, notably software where it is used in the so-called fuzzy logic arena.
It’s only smart when used effectively in any situation in which is utilised. That often means providing an explanation of why something didn’t work and a path to put it right for the future, something which appliance manufacturers totally fail to do. A sequential blinking light with no explanation of meaning is not what I would consider a reasonable explanation of or for failure. Usually this arise a fault description along the lines of, “the damn thing doesn’t work”, accented by total frustration on the part of the customer, accenuated by us asking where it stopped etc. and what the symptoms are when the poor customer hasn’t the foggiest.
And we wonder why customers are tee’d off.
It can be smarter and it can be better, the will to make it so is obviously lacking.
E2 anyone?
K.
Re: Fuzzy logic
I’m interested Andy….. Had hoped for more knowledgeable responses than I might be able to offer.
The first fuzzy logic machines I came across were the Bosch ones. The more I looked at what they were trying to do, the more convinced I became that the key was simply a hair trigger pressure switch set up in order to dose the laundry more precisely.
The bulk hopper dispenser was prototyped by Zerowatt some years ago as a liquid bag dispenser – I have no idea if it ever made, it certainly was only a fixed charge dispenser system.
As Kevin says, we now have infrared turbidity sensors, add to that ntc digital temperature control and “proportional” pressure switches – the limit can now surely only the ability to programme the processor and keep it to a sensible budget.
Cheers,
Chris.Re: Fuzzy logic
Oh Zerowatt and anything close to technical sends shivers down my spine, still!
In so far as I know there are no domestic machines with fixed detergent dispencer systems. Too many variables as Penguin knows given that we tied him down and made him sit through the detergent training whilst propping in eyes open in true Clockwork Orange style. 😆
Seriusly though, there’s too many variables and it’s a well known fact that if you take the control away from people that they will rebel against it, just look at speed camers and burning tyres or GPS tracking. Okay, extreme examples, but you get the picture. So the customer has to have some degree of control.
If you accept that then the point of Fuzzy Logic is pretty much negated, in fact I seem to recall several complaints about it with regard to Bosch, basically the punters didn’t like it. The control had been removed and the damn thing didn’t work. or at least work the way that the punter wanted it to work.
I can see the point of a proportional pressure switch, that makes sense. Turbidity, maybe. But what happens if the water ain’t so hot and a bit cloudy… system goosed. NTC’s, well okay but you could do a lot more with them than is IMO… but not on an RRP of £200.
Fuzzy Logic should have been billed as, “this will totally confuse you and not do the job unless you study the book diligently and behave yourself just as a true German would, with Teutonic efficiency.” Then it will work.
God help us, the Italians have it too now! 😕
K.
Re: Fuzzy logic
Andy
The wash detergent works in a complete dosage, determined by the water hardness. As those who have had the wash training already know, the correct amount of builders and surfacants are required to soften the water and remove stains. Limiting the supply, then adding more will upset the chemical reactions required, I don’t think that will work.Under/overdosing is a problem to turbidity sensors as over foaming completely “freaks” the infra red ability and its fault code time.
The best example is Whirlpool Dishwashers, over foaming aborts the programme, however when the engineer gets there its hard to fault (foam evaporated).
The new “Frequency” pressure switches seem to coping ok, not causing us problems.
Kevin
Re: Fuzzy logic
Right! we will bin that idea then. It was only something which I was chewing over but I don’t really know much about the properties of detergents which is why i would like the training session at some time.
Kevin – when you mentioned the ‘Frequency’ pressure switches is this what Chris refered to as ‘proportional’ pressure switches?
Are these the same as the electronic presure s/w that Zanussi use? (where tha actual level of water can be determined, rather that having fixed levels). If not could you please explain what you mean?
Re: Fuzzy logic
didn`t one of the late eighties Electrolux washing machines (Zanussi manufatured), have a large automatic detergent container in the base of the washing machine? Can`t remember the model though.
Re: Fuzzy logic
Frequency switches are exactly that.
Where a certain pressure upon a crystal gives an emf output. The output is calibrated in litres, so on some appliances during fault finding the exact litreage can be seen in the digital display.
You will still get the problems associated with “Gunge” in the pressure pipe, but if the customer is instructed in the detergent technology then even this fault will be rare.
The frequency level switches are much smaller, have no need of different levels, usually have two wires only, and guess what, are fitted to our Project X appliance. Water levels are extremely accurate and therefore different “soak” levels are taken care of very quickly. Remember listening to a Hotpoint fill, several seconds later it starts to fill again, come to think of it so does a Servis LOL
Hope that helps.
KevinRe: Fuzzy logic
kheath wrote: come to think of it so does a Servis LOL
Until the module goes bang 😉
LawrenceRe: Fuzzy logic
Thanks for that info Kevin. Thats really interesting about the crystal, r u saying that this is piezoelectric output from the crystal? If so, i did not know that they could be so sensitive to such small pressure changes.
The Zanussi p.s/w uses a variable inductance the core of which is moved directly by the bellows. The output is only three wires so it is either analogue or a serial data stream (A to D conversion done on the device). There are several sm IC’s within the device so option two is a possiblity.
Andy 🙂
Re: Fuzzy logic
kwatt wrote:Seriusly though, there’s too many variables and it’s a well known fact that if you take the control away from people that they will rebel against it, just look at speed camers and burning tyres or GPS tracking. Okay, extreme examples, but you get the picture. So the customer has to have some degree of control.
If you accept that then the point of Fuzzy Logic is pretty much negated, in fact I seem to recall several complaints about it with regard to Bosch, basically the punters didn’t like it. The control had been removed and the damn thing didn’t work. or at least work the way that the punter wanted it to work.
K.I don’t think its going to go away Ken. These are the first tentative steps towards introducing artificial intelligence into the domestic environment. Because this is what fuzzy logic is – handing over more decisions to the machines! Who knows what will be in our homes in another 50 years.
Aaaah! Be alert, the teminator may materialise before your eyes before too long. Better :plug: now before its too late
Re: Fuzzy logic
andy2 wrote:I don’t think its going to go away Ken. These are the first tentative steps towards introducing artificial intelligence into the domestic environment. Because this is what fuzzy logic is – handing over more decisions to the machines! Who knows what will be in our homes in another 50 years.
🙂
My house talks to me and stuff operates automatically all over the place. I’m a bit ahead on this front as Kevin will tell you. 😉
I’ve been using a house and many other devices with “fuzzy logic” for nearly ten years.
K.
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