Re: What is the catch with those JMC servo IHSV60-30-40-48
Quote:
Originally Posted by
maxspongebob
Well, I tried to search this forum for the term "JERK FACTOR" and the only thing that came up was your posts. SO........
It does help if you know what you are looking for
Not sure why you replied if you don't know what the problem is when using low count Encoders, ask in the real world you may get the answer if you know what to look for, some high end controls are now including Jerk control in there software to help over come this problem also, even with using high PPR Encoders this is the next step for software developers, here is a snip related to using a control that has advanced jerk control
.
Digital signal processing with computer circuits and software has encouraged control engineers to realize more capable control algorithms that today include jerk control. Today, "servos" can be defined as the use of negative feedback for the position, velocity, acceleration and jerk of inertial loads.
"Jerk" is the time rate of change of acceleration. It is the acceleration of the acceleration.
Jerk ramps the acceleration to smooth the velocity. Steps—sharp edges in command values—tend to excite mechanical systems to oscillate at their natural (resonant) frequencies. The bigger the step, the greater this tendency. If a system is not rigid relative to the performance that is expected of it, control over jerk can round the velocity corners. This reduces the amplitudes of the frequencies that excite resonance oscillation. As a result, acceleration factors can be set higher.
With higher acceleration factors, a tool can transition corners and traverse contours of constantly changing curvature at a faster rate, and do so more smoothly when the corners of both the longitudinal and lateral acceleration are ramped.
There are ( 2 ) things that can help to control machine "jerk" Encoder PPR and enhanced software, the control software is out of the range of most Hobby user but High PPR Encoders are not, any good AC servos have a minimum of a 16Bit Encoder, which is available and most Hobby user's can afford, this will help to smooth out a not so rigid machine and add a much better cut performance
The Performance difference between a 1000 PPR Encoder and a 65,536 PPR ( 16Bit ) Encoder you can see it, feel it, and enjoy the end results
Re: What is the catch with those JMC servo IHSV60-30-40-48
Quote:
Originally Posted by
mactec54
It does help if you know what you are looking for
Not sure why you replied if you don't know what the problem is when using low count Encoders, ask in the real world you may get the answer if you know what to look for, some high end controls are now including Jerk control in there software to help over come this problem also, even with using high PPR Encoders this is the next step for software developers, here is a snip related to using a control that has advanced jerk control
.
Digital signal processing with computer circuits and software has encouraged control engineers to realize more capable control algorithms that today include jerk control. Today, "servos" can be defined as the use of negative feedback for the position, velocity, acceleration and jerk of inertial loads.
"Jerk" is the time rate of change of acceleration. It is the acceleration of the acceleration.
Jerk ramps the acceleration to smooth the velocity. Steps—sharp edges in command values—tend to excite mechanical systems to oscillate at their natural (resonant) frequencies. The bigger the step, the greater this tendency. If a system is not rigid relative to the performance that is expected of it, control over jerk can round the velocity corners. This reduces the amplitudes of the frequencies that excite resonance oscillation. As a result, acceleration factors can be set higher.
With higher acceleration factors, a tool can transition corners and traverse contours of constantly changing curvature at a faster rate, and do so more smoothly when the corners of both the longitudinal and lateral acceleration are ramped.
There are ( 2 ) things that can help to control machine "jerk" Encoder PPR and enhanced software, the control software is out of the range of most Hobby user but High PPR Encoders are not, any good AC servos have a minimum of a 16Bit Encoder, which is available and most Hobby user's can afford, this will help to smooth out a not so rigid machine and add a much better cut performance
The Performance difference between a 1000 PPR Encoder and a 65,536 PPR ( 16Bit ) Encoder you can see it, feel it, and enjoy the end results
Putting other peoples writing and research forward as your own is called "Plagiarism". If you are going to use others work then you should provide an attribution or just link to their work so people know.
https://www.mmsonline.com/articles/u...g-jerk-control
As for the original question of using the IHSV60-30-40-48 in a direct drive configuration of a 2'x2' extruded aluminum gantry system driving 1605 ballscrews. I would say this. Searching this site revealed only one mention of this servo. That in itself is not a good sign. Also the only sellers that I could find on the internet were all over seas. Finally the only technical information that I could find was on the JMC website and it was almost entirely in Chinese.
If one was feeling adventurous you could buy one of the servo's and try it out. But I would not purchase all of the servos until you have tried one. You should also look at the tuning software, since it is a servo, it must be tuned. Although I did find the software on the JMC site, I did not want to run it on my PC.
In my opinion I don't think your application will be affected by the PPR of the encoders in these servo's. You mentioned the ClearPath servo setup for 800 PPR. I have 2 machines that are using these and I have no problem with uneven movement. Tuning the servo has a lot to do with this.
Re: What is the catch with those JMC servo IHSV60-30-40-48
Quote:
Originally Posted by
maxspongebob
Putting other peoples writing and research forward as your own is called "Plagiarism". If you are going to use others work then you should provide an attribution or just link to their work so people know.
You obvious can't read also, the post has nothing to do with Plagiarism get a life dude :wave:
What I posted I did not clam as my own, if you read you will see that I referred to it as a "snip" ( this is what I posted, here is a snip related to using a control that has advanced jerk control ) (wedge)
Quote:
Originally Posted by
maxspongebob
If one was feeling adventurous you could buy one of the servo's and try it out. But I would not purchase all of the servos until you have tried one. You should also look at the tuning software, since it is a servo, it must be tuned. Although I did find the software on the JMC site, I did not want to run it on my PC.
Now you are quoting what I have already posted :wave:
Re: What is the catch with those JMC servo IHSV60-30-40-48
Quote:
Originally Posted by
maxspongebob
As for the original question of using the IHSV60-30-40-48 in a direct drive configuration of a 2'x2' extruded aluminum gantry system driving 1605 ballscrews. I would say this. Searching this site revealed only one mention of this servo. That in itself is not a good sign. Also the only sellers that I could find on the internet were all over seas. Finally the only technical information that I could find was on the JMC website and it was almost entirely in Chinese.
If one was feeling adventurous you could buy one of the servo's and try it out. But I would not purchase all of the servos until you have tried one. You should also look at the tuning software, since it is a servo, it must be tuned. Although I did find the software on the JMC site, I did not want to run it on my PC.
In my opinion I don't think your application will be affected by the PPR of the encoders in these servo's. You mentioned the ClearPath servo setup for 800 PPR. I have 2 machines that are using these and I have no problem with uneven movement. Tuning the servo has a lot to do with this.
Well i guess i should then leave the preliminary investigation for others. on the other side, there is some nice thing said on youtube about is little brother, the IHSV57-30-18-36. Sorotec.de sells it for 249 eur. and they sell a tuning cable,. I might leave this to more experimented people.
1 Attachment(s)
Re: What is the catch with those JMC servo IHSV60-30-40-48
Quote:
Originally Posted by
HuguesP
Well i guess i should then leave the preliminary investigation for others. on the other side, there is some nice thing said on youtube about is little brother, the IHSV57-30-18-36. Sorotec.de sells it for 249 eur. and they sell a tuning cable,. I might leave this to more experimented people.
I would not give up on this as they are a good price and may work well on your machine build, as long as you get what information is needed that I posted in #9 you should be fine, contact the supplier and ask if it come's with tuning software and Cable
The motor size 400w is ok for your machine
Here is where you can get your Timing Pulleys from
https://www.sdp-si.com/products/Timi...leys/index.php
https://sdp-si.com/eStore/CenterDistanceDesigner
The GT-2-5 with 15mm wide is Ideal for what you need
In the designer select Metric and 5mm GT-2 and look at all the options, in most cases you have to Bore out the Timing Pulleys to suit what they are mounting on
Here is a Video of a 400w motor this machine works well and is a similar size to what you are building
https://www.youtube.com/watch?v=iTBr_rJXZSw
Re: What is the catch with those JMC servo IHSV60-30-40-48
thanks for the info, I will certainly look at this and see if a belt system could fit in my minimalist build ( or planned build)
Re: What is the catch with those JMC servo IHSV60-30-40-48
Hi,
there are a number of very cheap AC servos coming out of China, they work but the quality and backup is questionable.
May I suggest looking at DMM servos, a Canadian company that manufacture in China. In a short time they have carved out a reputation
for quality and backup.
I favor Delta servos. They are a Taiwanese company manufacturing in China. They have a long established reputation for quality. Note that
on Ebay and places like that there are many servos/drives that look like Delta but are in fact copies, the only thing to recommend them is they
are cheap. Get genuine Delta. I have just bought four servos and drives of their B2 series, that is with 17 bit incremental encoders.
I've bought one 400W 23 size example, two 750W 34 size unbraked and one 750W braked example. They are superb.
I recommend either Delta or DMM as 'quality at a price'. Cheaper servos are just that ....cheaper and lesser quality.
Craig
Re: What is the catch with those JMC servo IHSV60-30-40-48
Quote:
Originally Posted by
joeavaerage
Hi,
there are a number of very cheap AC servos coming out of China, they work but the quality and backup is questionable.
May I suggest looking at DMM servos, a Canadian company that manufacture in China. In a short time they have carved out a reputation
for quality and backup.
I favor Delta servos. They are a Taiwanese company manufacturing in China. They have a long established reputation for quality. Note that
on Ebay and places like that there are many servos/drives that look like Delta but are in fact copies, the only thing to recommend them is they
are cheap. Get genuine Delta. I have just bought four servos and drives of their B2 series, that is with 17 bit incremental encoders.
I've bought one 400W 23 size example, two 750W 34 size unbraked and one 750W braked example. They are superb.
I recommend either Delta or DMM as 'quality at a price'. Cheaper servos are just that ....cheaper and lesser quality.
Craig
I have looked at the DMM 400W for a long time, as a Canadian myself it would be a good way to encourage my country, on the other side, the price is far more than what i was aiming for... Sure if in 3 years i can resell them 80% of the price I paid, it mitigate the risk, but this is data i don't have.
Re: What is the catch with those JMC servo IHSV60-30-40-48
Hi,
this a quote (mangled) from a supplier:
'There is always a manufacturer somewhere prepared to produce an item cheaper but of lesser quality. People who buy on price alone
are that manufacturers legitimate prey'
Craig
Re: What is the catch with those JMC servo IHSV60-30-40-48
DMM's are 3x the price, which can make a huge difference for a hobbyist.
I'd seriously consider these, but there are a few issues for me.
You need a DC power supply with a lot of current. I'm guessing the peak current is around 20 amps each. But DMM uses a single 20 amp power supply with 3 DYN2 drives, so I'm thinking a 48V 30 amp supply should work for 3 motors?
This adds about $200-$250 to the cost of the motors vs AC drives
You need to run your step dir signals all the way to the drives. But there's no encoder cables, so it's a wash.
1000 line encoders? Not sure how they can get 40,000 steps out of these, unless they are just using electronic gearing? This makes no sense. But I'm not sure if it would be an issue on a router?
The manual mentions keeping them away from dust. Not sure how important this is, but it definitely might be an issue on a router.
Re: What is the catch with those JMC servo IHSV60-30-40-48
It has been my experience that you get what you pay for. Good hardware is never the cheapest. One also has to consider the value of one's time in the cost equation. Whenever I have taken the low cost route, it has resulted in an outcome that required more of my time debugging, fighting with a vendor over a return, or just having to put in more effort to get the outcome that I wanted.
However, if you are willing to trade your effort for something that is innovative, risky, and maybe a lower $ cost, there are options. Take a look at ODrive Robotics. They have a device that turns a brushless DC motor into a servo.
Re: What is the catch with those JMC servo IHSV60-30-40-48
I ordered a pair for a benchtop lathe project.
I'll be hooking them up hopefully in January when all of the parts get here. Belt reduction parts, servos and power supply.
They require 7.5 Amps each, plus/minus, so I ordered an Antek torroidal power supply. About 130$, but I'd be using a 90$ one from them for a stepper machine. Not a big price difference.
