"Automatic control" doesn't involve the human direct involvement throughout the whole process
"Self regulation" doesn't involve the human direct involvement throughout the whole process
Importing and modifying a new mini excavator from China
- Thread starter dfkrug
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"Self regulation" doesn't involve the human direct involvement throughout the whole process
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dfkrug
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No. Visual feedback by the operator of the position of his control lever is not enough in your case. If that action is amplified or powered by a secondary power source powering a secondary mechanism, then it is a servomechanism. If the operator used some kind of motor to turn his gate valve handle, and his action only operated that motor, then he would have a servomechanism in the basic sense of that word.
Back in the 40s or 50s, someone built the first "waldo", which was a type of servomechanism that allowed the operator to use electric motors that he controlled with his fingers to power and control the movement (and amplification) of a mechanical manipulator. I would call that a servomechanism. Feedback was only visual, initially.
I am not disputing that some companies or industries take terms that have English meanings and use them only in a narrower definition.
jaylast
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That's the goal to expound thought (and communication) potential with deeper understanding and use of language.
Agree. Also agree with industry accepted use of the terms.
Servo to describe hydraulic pilot is a fun stretch/reach imo, based on any definitions I've read, but also agree use in that case actually complicates things by being less descript (even if reader can make the same stretch/reach in definition)
No big deal though Ima keep referring to my EM 15 as pilot or hydro pilot. Saving 'servo' for if I ever manage to upgrade something like the thumb aux circuit to a switch driven action on the joystick.
Pretty cool, L 12 would be my first choice in the readily available mini's (since mine isn't very common, unfortunately) - H 15 possible choice also but I don't know much about them.
I think working a decent counterweight on it (and adding the hydro tank pickup extension if needed) are probably the two most meaningful things I'd do for L 12. I've seen them come stock with cooling and filtration. About 300lbs at the back should make a big difference in usability/tipping.
Applicable to any single pump style machine - I'm yet to see anyone try a 2 stage pump replacement and thing that would be interesting to try/do. Still not sure what if any benefit there really is to one.
Switch driven hydraulic valves are very common as third functions but we just call them solenoid valves. Several use a solenoids to control a pilot section which controls the main spool. Some even have position sensors to have verification if they are open or closed but no one still calls them servos unless they can control position and maintain it everywhere between open and close.
As many more sophisticated attachments are being put on skid steers and excavators, many have separate hi flow engageable pumps on the third function. They are actually controlling the pumps stroke cylinder with a servo valve to control the speed without wasting energy and safely deals with high acceleration and braking pressures of high rotational mass attachments.
Servo valves allow some very unique functionality. Most spool valves, even pilot operated ones are not linear in their flow, its very much a curve and it is not always advantageous to fine control. The computer can be programmed to take a potentiometer value and give a very linear feel to the operation even though the fluid flow is not linear by having a table of corrections that were derived by the manufactures flow test. It can even be programmed to modify action (without the operator) to adjust flow depending if the machine is cold or hot having the same "feel" to the operator.
Pressing a switch can then put it into slow or turtle mode and have the computer give a very non linear curve to the control feel. This is very flat on the first 50 percent of potentiometers values and then starts to rise but is still restrained in a steeper curve over the last 50 percent. This gives extremely fine control.
We would see operators in the tracked skid steers that were soso operators with a pilot pressure machine look like pros in a servo valved machine due to the computer.
Machines like the large excavators and dozers don't just have position feed back in the valve itself but in the cylinders. The operator can attach a bucket and calibrate the stick on his display, and then he can dig a trench with an exact grade on the bottom. The machine will not let him dig any lower than that grade no matter what the orientation of the boom or bucket is and doesn't have to stop and carefully check with a laser detector mounted on the boom
LittleBill21
Veteran Member
what is this?
This is a good explination of it.
Linear variable differential transformer - Wikipedia
They are not as precise as linear encoders but much less fragile and cheaper. They do good enough for use in servo/proportional valves except in the most critical processes requiring absolute control.
You realize this thread is about 5k Chinese mini excavators?
I do.
And that's why I brought it up.
Why use the terminology for tech that much more expensive excavators use when we are talking about low tech Chinese excavators?
It just causes confusion and leads to people that are not as well versed in hydraulics to conflate the two systems as the same in their mind.
The manufactures and importers already spread to much unclear info to just plain lies about the machines to entice buyers that don't have the knowledge to deal with the challenges of owning a Chinese excavator.
I didn't purchase a Chinese mini excavator because I had any notion that it would be just like a name brand mini
oldrustysteel
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My thoughts exactly. I dont get into correcting some
ones spelling, grammar or possible slightly misuse of a word. Dfkrug tries to explain things so that even I can understand it.
I for one appreciate his willingness to try and help people like me. I fail to see how this line of scrutiny helps any of us with our cheap baby diggers.
A Slight "misuse of the word" is 10k in differences in cost of the two types of equipment being discussed.My thoughts exactly. I dont get into correcting some
ones spelling, grammar or possible slightly misuse of a word. Dfkrug tries to explain things so that even I can understand it.
I for one appreciate his willingness to try and help people like me. I fail to see how this line of scrutiny helps any of us with our cheap baby diggers.
I don't consider that disparity slight. Literally more than these baby diggers cost.
I as well appreciate his willingness to help? Does that make his statements above discussion?