Just come cross this video it’s nice and detailed explanation but you never competed RAS to S-Curves with for me is exactly this same thing just you use different name. S-profile have 7 characteristic also include smooth increasing or decreasing of acceleration. And torque curve looks like RAS, can we have comet on this ?
Hi Marek, This is an excellent question, although not an easy one to answer concisely, so please bear with my long answer. I think it will clarify the differences between “s-curve” and RAS™. Assuming our goal is to make motion as smooth as possible, and with minimal vibration and settling time, we need to make sure that the velocity-vs-time move profile never requires an instantaneous change in motor torque. Not only is it impossible for any real-world system to follow an instantaneous change, but by trying to do so, the system will generate shock, noise, and vibration. These negative effects are bad for performance and cause excessive wear on the mechanical system. The common trapezoidal move profile, with its sharp corners, clearly asks the motor to instantly change the torque it puts into the system. Most people intuitively understand this because the sharp discontinuities are easily seen. (7:44 shows this graphically) What’s less obvious is that even a smooth looking velocity profile can demand instantaneous changes in torque. To understand why, consider that the torque required by a motion system is proportional to the acceleration required. So, if we want to make sure a profile never requires the torque to change instantaneously, we need to make sure it never requires the acceleration to change instantaneously. In other words, any change to acceleration must be gradual. The term “s-curve” is used a bit loosely in industry; it’s used by some manufacturers to refer to substituting a half cosine curve in place of the linear acceleration of a trapezoidal velocity profile. Other manufacturers use “s-curve” to describe a velocity profile with a constant jerk (rate of change of acceleration) at the beginning and end of the acceleration parts of the move. The latter is called “jerk-limiting” because the jerk is held to a constant finite value (or zero, during the constant acceleration and constant velocity parts of the move). A mechanical analogy that might help visualize constant jerk is putting a circular (i.e., constant radius) fillet into the corners of a trapezoidal profile. A jerk-limited velocity profile looks smooth, but the acceleration is zero at the start of the move and abruptly starts ramping up at a constant rate. Then, as the acceleration limit is reached, it abruptly stops increasing. In other words, although the velocity profile looks smooth, the acceleration profile of this move is a trapezoid with sharp corners. This means the torque will have to change abruptly, causing noise, vibration and longer settling time for the mechanical system. (8:40 shows this graphically) The half cosine type of s-curve is a little better, but still has abrupt transitions in the acceleration profile, and has the additional disadvantage that the maximum jerk will increase for moves of short distance where the maximum velocity is not reached. This is because it tries to fit the same half cosine into a shorter time period, and this makes the rate of change of acceleration (i.e., the jerk) increase. Even worse, some manufacturers will just truncate the cosine when constant velocity is reached. This results in a very discontinuous profile. With normal jerk-limited profiles, you can set the jerk limit to the maximum value you can accept for your system, and the profile should never exceed that limit. The RAS feature not only limits the jerk (regardless of move parameters), but also limits the rate of change of the jerk to a constant value. Limiting the second derivative of acceleration in this way means that the acceleration profile, instead of being a trapezoid, is nice and smooth. (11:07 shows this graphically) With the RAS feature, there are no abrupt changes in torque at any point in the move profile under any circumstances. Having read this explanation, take a few minutes to re-watch the video from 7:44 to 13:30. That section of the video explains, in graphical terms, how the torque requirements are different for trapezoidal, jerk-limited, and RAS profiles. One final note: the RAS is available in all Teknic products that have a built-in motion profile generator (e.g., MC and SC-series ClearPath motors), but also in products that accept step & direction motion profiles from a third-party controller. In the latter case, you should actually select a trapezoidal move profile within your controller, and allow the RAS to convert the profile on the fly into a jerk- and jerk-derivative limited profile. A demo of this (including the effect of RAS on the torque) can be seen in the ClearPath Step & Direction video, starting at 1:10. I hope this clarifies the advantage of the RAS compared to other techniques that attempt to reduce profile-induced vibration and noise. Please feel free to email us at support@teknic.com if you have further questions. Best regards, Zach H.
@@TeknicInc "With the RAS feature, there are no abrupt changes in torque", as I understand this, this is the same with limiting jerk. There is no jump in acceleration, it only starts increasing at a limited rate. So, to convince the audience, please show a jerk-limited profile in comparison to RAS (or 3rd-order to 4th-order limiting?). Another consideration is the time used for the whole movement. In the introduction demo I hear that the move with RAS is at a much higher speed (heigher frqeuency, I guess at least 1.5x, may be 2x). That's probably ok for applications that don't have a physically limit on speed. But it increases the acceleration time for speed limited applications that are already at their limit. In your example curves at ruclips.net/video/WOyP51-PiTs/видео.html we see, that the time increases from 2 to 3 sections by switching the profile. I understand, that it's not the complete deceleration curve, but your demo shows, that it's not insignificant for this application as the speed increases drastically. Another consideration is resonance. Resonances are the limiting factor in many cases. My hope is that resonances can be eliminated completely by higher order limiting. This would make your products much more attractive, and I assume they can probably provide such an improvement. Can you give an example of such a resonance situation? But please don't restrict yourself to a single resonance case, instead show a frequency scan (e.g. by showing a sequence of moves back and forth with a changing distance), because different profiles usually only move the frequencies but don't eliminate them at all.
Hi @@aribowell, Thank you for taking the time to reach out. I apologize in advance for my long response. You have asked a number of good questions (questions that are frequently asked by other customers), and I wanted to take the time to answer you thoroughly. In the event you didn’t notice my colleague’s response to the original comment, he stated that: “Assuming our goal is to make motion as smooth as possible, and with minimal vibration and settling time, we need to make sure that the velocity-vs-time move profile never requires an instantaneous change in motor torque. Not only is it impossible for any real-world system to follow an instantaneous change, but by trying to do so, the system will generate shock, noise, and vibration.” In reading his comment, I thought it might be helpful if I tried to explain this in a slightly different way, with additional detail. Within position control servo systems, there are actually three separate “servos” operating at any time. These servos are responsible for minimizing the errors in position, velocity, and torque. One of the primary tenets of Teknic’s servo systems is that we never want to command one of these servos to do something that it cannot physically do. For most people, it is intuitive that it’s impossible for the velocity servo to follow an instantaneous step change to the acceleration (i.e., a sharp corner in the velocity profile). We solve this problem in the common trapezoidal velocity-vs-time command by limiting the jerk component command. What is less obvious is that a step change to the jerk - instantaneously transitioning from zero acceleration to a constant rate of change of acceleration (i.e., constant jerk) - causes a sharp corner in the required torque. The algorithm that servo controls the torque tries to follow the sharp corners, which causes machine vibration, noise, and other undesirable effects. The RAS limits the jerk-derivative of the motion profile which eliminates the sharp corners in the torque command, resulting in smoother and quieter motion. I do agree with you that seeing the differences in motion profiles (especially in the torque domain) can be very helpful in understanding this fairly complicated yet important point. If you re-watch the video starting at 13:00 (ruclips.net/video/WOyP51-PiTs/видео.html), the engineer in the video graphically compares the difference in the commanded torque when using the RAS or a jerk-limited profile. At 13:30 (ruclips.net/video/WOyP51-PiTs/видео.html) he overlays the commanded torque for these two profiles to help illustrate the differences. You mentioned that at one point in the video the audible frequency of the move changes. We didn’t change the velocity between those two moves. The difference in the sound of the two moves results from a subtle (yet important), secondary benefit of the RAS. Although the velocity profile of a servo may look smooth, if you zoom in, you will see that all digital servos have quantization effects. For example, what looks like a smooth ramp in speed is actually a very fine staircase of incremental jumps in speed. Acceleration feedforward gain, which is used in all good servos to reduce tracking error during acceleration and deceleration, produces lots of little “torque spikes” in response to each one of the little velocity stair steps. In addition to reducing the macro effects of noise and vibration by limiting the jerk and jerk-derivative, the RAS smoothes out the digitized nature of the servo system, reducing the torque “hash” caused by acceleration feedforward. What remains is just the higher frequency sound of the belt drive. If you’re interested in seeing another example of this, take a look at this video here (you can clearly hear _and see_ how much the RAS affects the torque): (ruclips.net/video/NbLE126rrRs/видео.html). Adding the RAS does lengthen the _commanded_ move time, but as shown in the original video, the RAS profile greatly reduces the overall time to move _and_ settle at the final position (even without increasing the move speed or acceleration). We are sometimes asked why the RAS doesn’t limit the 5th or 6th derivative of position. The quick answer is that after taking the 4th derivative of the position, and ensuring that there are no commanded discontinuities in any of our servo loops (i.e. position, velocity, or torque), further derivative limiting is of little (if any) practical value. While it is possible to implement further derivative limiting, doing so would increase the required burden on the motor’s DSP, which would limit our ability to implement other features that can improve performance. You asked about axes that suffer from resonance problems. Teknic offers another feature in certain ClearPath models and other products called “g-Stop”. The g-Stop algorithm does not work by derivative limiting; it actually creates very non-intuitive and odd-looking profiles, but is very effective in eliminating resonances. And it is very robust-once it is set up, you can use any combination of acceleration, velocity and move length, and the resonance will significantly attenuate in all cases. You can see a video demo of it here: ruclips.net/video/Aj1LyYEvstw/видео.html. I hope this helps! Please feel free to contact us directly through support@teknic.com if you have any other questions. Best regards, Jon K. - Teknic Servo Systems Engineer
thanks for the long and very clear answer and especially for answering each of my points. After looking the other video (that seems t be a bit more clear) where the non-RAS and RAS curves are displayed below each other on the same display, I noticed that I had misinterpreted the frequency. The non-RAS move has some lower frequencies *added*, which I thought to be comparable to the RAS frequency, instead the RAS frequencies are a subset of the non-RAS frequencies. I think, that relates to what you said about the filtering effect ("smoothing out the digitized nature"). According to the time: In the other video you can see, that the curve for RAS is slightly longer. I think the acceleration phases must become longer compared to profiles where only acceleration is limited (and usually at a constant maximum or zero), because smoothing the derivatives means that the acceleration is *not* at the maximum all the time. That's why I assumed a higher speed. And yes, I ignored the settle time for this point of view. My conclusion is, that all depends on how the application limits each of the derivatives. For some applications it's mainly speed (CNC machining), for some it's the force applied to a mass (so acceleration) and for others it might be the jerk (e.g. when audible noise should be kept low). Thanks for the link to the g-Stop algorithm, I will have a look at it.
Hi Rick, To achieve coordinated motion with the ClearPath SD series on a multi-axes system, you'll need to enter the same RAS value for each axis. This assumes that the motion controller is supplying properly coordinated moves. Determining the appropriate RAS value for your machine requires some testing with different values. The general approach is to start testing with the lowest value in the appropriate range below (based on the type of machine you are testing) and run some test cuts. During the test cuts, you should be running at your maximum acceleration and cut speed. After testing with the lower end of the range, raise the RAS setting up through the range and retest. Here are some typical RAS settings for CNC machines: Laser CNC 9ms-16ms Wood router 16ms-24ms Stone cutter 24ms-44ms Plasma cutter 24ms-44ms Since the RAS is being applied to the command, you need to be careful not to set the RAS too high. Setting the RAS too high will effectively change the pattern itself. The highest RAS value that produces good results without sacrificing cut quality is usually the optimal value. As you increase the RAS setting ,your motion will become smoother because the RAS is reducing the amount of jerk in the command. The RAS time will be added to your move time e.g. a 1 second move with a 24ms RAS will yield a move time of 1.024 seconds. Since the jerk has been reduced and the motion is smoother, you will almost certainly be able to raise your rate of acceleration. Most users find out that their move time is actually shorter when using the RAS, not longer. Please feel free to email us at support@teknic.com if you have any other questions. Best regards, Aaron B.
Hi Roman, Yes, Teknic's RAS feature is available in all ClearPath models, including the ClearPath "Stepper Killer" (SDSK) models. The "Regular" (R) encoder resolution option of the SDSK models has RAS settings up to 16 ms. The "Enhanced" (E) encoder option has the full selection of RAS (and 8x the commandable encoder resolution), You can view all of Teknic's SDSK and SDHP models at: www.teknic.com/products/clearpath-brushless-dc-servo-motors/clearpat,h-sd/all-sd-models/#ppsShowPopUp_100. Please feel free to contact us directly through support@teknic.com if you have any other questions! Best regards, Aaron B. - Teknic Servo Systems Engineer
Hi YUP, While PID control loops (or PIV for ClearPath) and RAS are both used to improve servo performance, they operate in completely different ways. PID control loops use feedback to proportionally control the servo response. RAS does not change how the servo responds to the command, but instead, modifies the incoming command to reduce jerk and jerk derivative. If you have additional questions about how RAS can benefit your application, please reach out to Teknic’s support (teknic.com/contact/) or give us a call at 585-784-7454. Best, Bradley N. - Teknic OEM Application Engineer
Just come cross this video it’s nice and detailed explanation but you never competed RAS to S-Curves with for me is exactly this same thing just you use different name. S-profile have 7 characteristic also include smooth increasing or decreasing of acceleration. And torque curve looks like RAS,
can we have comet on this ?
Hi Marek,
This is an excellent question, although not an easy one to answer concisely, so please bear with my long answer. I think it will clarify the differences between “s-curve” and RAS™.
Assuming our goal is to make motion as smooth as possible, and with minimal vibration and settling time, we need to make sure that the velocity-vs-time move profile never requires an instantaneous change in motor torque. Not only is it impossible for any real-world system to follow an instantaneous change, but by trying to do so, the system will generate shock, noise, and vibration. These negative effects are bad for performance and cause excessive wear on the mechanical system.
The common trapezoidal move profile, with its sharp corners, clearly asks the motor to instantly change the torque it puts into the system. Most people intuitively understand this because the sharp discontinuities are easily seen. (7:44 shows this graphically)
What’s less obvious is that even a smooth looking velocity profile can demand instantaneous changes in torque. To understand why, consider that the torque required by a motion system is proportional to the acceleration required. So, if we want to make sure a profile never requires the torque to change instantaneously, we need to make sure it never requires the acceleration to change instantaneously. In other words, any change to acceleration must be gradual.
The term “s-curve” is used a bit loosely in industry; it’s used by some manufacturers to refer to substituting a half cosine curve in place of the linear acceleration of a trapezoidal velocity profile. Other manufacturers use “s-curve” to describe a velocity profile with a constant jerk (rate of change of acceleration) at the beginning and end of the acceleration parts of the move.
The latter is called “jerk-limiting” because the jerk is held to a constant finite value (or zero, during the constant acceleration and constant velocity parts of the move). A mechanical analogy that might help visualize constant jerk is putting a circular (i.e., constant radius) fillet into the corners of a trapezoidal profile.
A jerk-limited velocity profile looks smooth, but the acceleration is zero at the start of the move and abruptly starts ramping up at a constant rate. Then, as the acceleration limit is reached, it abruptly stops increasing. In other words, although the velocity profile looks smooth, the acceleration profile of this move is a trapezoid with sharp corners. This means the torque will have to change abruptly, causing noise, vibration and longer settling time for the mechanical system. (8:40 shows this graphically)
The half cosine type of s-curve is a little better, but still has abrupt transitions in the acceleration profile, and has the additional disadvantage that the maximum jerk will increase for moves of short distance where the maximum velocity is not reached. This is because it tries to fit the same half cosine into a shorter time period, and this makes the rate of change of acceleration (i.e., the jerk) increase. Even worse, some manufacturers will just truncate the cosine when constant velocity is reached. This results in a very discontinuous profile. With normal jerk-limited profiles, you can set the jerk limit to the maximum value you can accept for your system, and the profile should never exceed that limit.
The RAS feature not only limits the jerk (regardless of move parameters), but also limits the rate of change of the jerk to a constant value. Limiting the second derivative of acceleration in this way means that the acceleration profile, instead of being a trapezoid, is nice and smooth. (11:07 shows this graphically)
With the RAS feature, there are no abrupt changes in torque at any point in the move profile under any circumstances.
Having read this explanation, take a few minutes to re-watch the video from 7:44 to 13:30. That section of the video explains, in graphical terms, how the torque requirements are different for trapezoidal, jerk-limited, and RAS profiles.
One final note: the RAS is available in all Teknic products that have a built-in motion profile generator (e.g., MC and SC-series ClearPath motors), but also in products that accept step & direction motion profiles from a third-party controller. In the latter case, you should actually select a trapezoidal move profile within your controller, and allow the RAS to convert the profile on the fly into a jerk- and jerk-derivative limited profile. A demo of this (including the effect of RAS on the torque) can be seen in the ClearPath Step & Direction video, starting at 1:10.
I hope this clarifies the advantage of the RAS compared to other techniques that attempt to reduce profile-induced vibration and noise. Please feel free to email us at support@teknic.com if you have further questions.
Best regards,
Zach H.
@@TeknicInc "With the RAS feature, there are no abrupt changes in torque", as I understand this, this is the same with limiting jerk. There is no jump in acceleration, it only starts increasing at a limited rate.
So, to convince the audience, please show a jerk-limited profile in comparison to RAS (or 3rd-order to 4th-order limiting?).
Another consideration is the time used for the whole movement. In the introduction demo I hear that the move with RAS is at a much higher speed (heigher frqeuency, I guess at least 1.5x, may be 2x). That's probably ok for applications that don't have a physically limit on speed. But it increases the acceleration time for speed limited applications that are already at their limit.
In your example curves at ruclips.net/video/WOyP51-PiTs/видео.html we see, that the time increases from 2 to 3 sections by switching the profile. I understand, that it's not the complete deceleration curve, but your demo shows, that it's not insignificant for this application as the speed increases drastically.
Another consideration is resonance. Resonances are the limiting factor in many cases. My hope is that resonances can be eliminated completely by higher order limiting. This would make your products much more attractive, and I assume they can probably provide such an improvement.
Can you give an example of such a resonance situation? But please don't restrict yourself to a single resonance case, instead show a frequency scan (e.g. by showing a sequence of moves back and forth with a changing distance), because different profiles usually only move the frequencies but don't eliminate them at all.
Hi @@aribowell,
Thank you for taking the time to reach out. I apologize in advance for my long response. You have asked a number of good questions (questions that are frequently asked by other customers), and I wanted to take the time to answer you thoroughly.
In the event you didn’t notice my colleague’s response to the original comment, he stated that: “Assuming our goal is to make motion as smooth as possible, and with minimal vibration and settling time, we need to make sure that the velocity-vs-time move profile never requires an instantaneous change in motor torque. Not only is it impossible for any real-world system to follow an instantaneous change, but by trying to do so, the system will generate shock, noise, and vibration.”
In reading his comment, I thought it might be helpful if I tried to explain this in a slightly different way, with additional detail.
Within position control servo systems, there are actually three separate “servos” operating at any time. These servos are responsible for minimizing the errors in position, velocity, and torque.
One of the primary tenets of Teknic’s servo systems is that we never want to command one of these servos to do something that it cannot physically do. For most people, it is intuitive that it’s impossible for the velocity servo to follow an instantaneous step change to the acceleration (i.e., a sharp corner in the velocity profile). We solve this problem in the common trapezoidal velocity-vs-time command by limiting the jerk component command.
What is less obvious is that a step change to the jerk - instantaneously transitioning from zero acceleration to a constant rate of change of acceleration (i.e., constant jerk) - causes a sharp corner in the required torque. The algorithm that servo controls the torque tries to follow the sharp corners, which causes machine vibration, noise, and other undesirable effects. The RAS limits the jerk-derivative of the motion profile which eliminates the sharp corners in the torque command, resulting in smoother and quieter motion.
I do agree with you that seeing the differences in motion profiles (especially in the torque domain) can be very helpful in understanding this fairly complicated yet important point. If you re-watch the video starting at 13:00 (ruclips.net/video/WOyP51-PiTs/видео.html), the engineer in the video graphically compares the difference in the commanded torque when using the RAS or a jerk-limited profile. At 13:30 (ruclips.net/video/WOyP51-PiTs/видео.html) he overlays the commanded torque for these two profiles to help illustrate the differences.
You mentioned that at one point in the video the audible frequency of the move changes. We didn’t change the velocity between those two moves. The difference in the sound of the two moves results from a subtle (yet important), secondary benefit of the RAS.
Although the velocity profile of a servo may look smooth, if you zoom in, you will see that all digital servos have quantization effects. For example, what looks like a smooth ramp in speed is actually a very fine staircase of incremental jumps in speed. Acceleration feedforward gain, which is used in all good servos to reduce tracking error during acceleration and deceleration, produces lots of little “torque spikes” in response to each one of the little velocity stair steps.
In addition to reducing the macro effects of noise and vibration by limiting the jerk and jerk-derivative, the RAS smoothes out the digitized nature of the servo system, reducing the torque “hash” caused by acceleration feedforward. What remains is just the higher frequency sound of the belt drive. If you’re interested in seeing another example of this, take a look at this video here (you can clearly hear _and see_ how much the RAS affects the torque): (ruclips.net/video/NbLE126rrRs/видео.html).
Adding the RAS does lengthen the _commanded_ move time, but as shown in the original video, the RAS profile greatly reduces the overall time to move _and_ settle at the final position (even without increasing the move speed or acceleration).
We are sometimes asked why the RAS doesn’t limit the 5th or 6th derivative of position. The quick answer is that after taking the 4th derivative of the position, and ensuring that there are no commanded discontinuities in any of our servo loops (i.e. position, velocity, or torque), further derivative limiting is of little (if any) practical value. While it is possible to implement further derivative limiting, doing so would increase the required burden on the motor’s DSP, which would limit our ability to implement other features that can improve performance.
You asked about axes that suffer from resonance problems. Teknic offers another feature in certain ClearPath models and other products called “g-Stop”. The g-Stop algorithm does not work by derivative limiting; it actually creates very non-intuitive and odd-looking profiles, but is very effective in eliminating resonances. And it is very robust-once it is set up, you can use any combination of acceleration, velocity and move length, and the resonance will significantly attenuate in all cases. You can see a video demo of it here: ruclips.net/video/Aj1LyYEvstw/видео.html.
I hope this helps! Please feel free to contact us directly through support@teknic.com if you have any other questions.
Best regards,
Jon K. - Teknic Servo Systems Engineer
thanks for the long and very clear answer and especially for answering each of my points. After looking the other video (that seems t be a bit more clear) where the non-RAS and RAS curves are displayed below each other on the same display, I noticed that I had misinterpreted the frequency. The non-RAS move has some lower frequencies *added*, which I thought to be comparable to the RAS frequency, instead the RAS frequencies are a subset of the non-RAS frequencies. I think, that relates to what you said about the filtering effect ("smoothing out the digitized nature").
According to the time: In the other video you can see, that the curve for RAS is slightly longer. I think the acceleration phases must become longer compared to profiles where only acceleration is limited (and usually at a constant maximum or zero), because smoothing the derivatives means that the acceleration is *not* at the maximum all the time. That's why I assumed a higher speed. And yes, I ignored the settle time for this point of view.
My conclusion is, that all depends on how the application limits each of the derivatives. For some applications it's mainly speed (CNC machining), for some it's the force applied to a mass (so acceleration) and for others it might be the jerk (e.g. when audible noise should be kept low).
Thanks for the link to the g-Stop algorithm, I will have a look at it.
@@TeknicInc , just a feedback, g-Stop seems to work really fantastic, thanks for the hint.
Excellent
What does this do to coordinated moves in two or more axes on SD models?
Hi Rick,
To achieve coordinated motion with the ClearPath SD series on a multi-axes system, you'll need to enter the same RAS value for each axis. This assumes that the motion controller is supplying properly coordinated moves.
Determining the appropriate RAS value for your machine requires some testing with different values. The general approach is to start testing with the lowest value in the appropriate range below (based on the type of machine you are testing) and run some test cuts.
During the test cuts, you should be running at your maximum acceleration and cut speed. After testing with the lower end of the range, raise the RAS setting up through the range and retest.
Here are some typical RAS settings for CNC machines:
Laser CNC 9ms-16ms
Wood router 16ms-24ms
Stone cutter 24ms-44ms
Plasma cutter 24ms-44ms
Since the RAS is being applied to the command, you need to be careful not to set the RAS too high. Setting the RAS too high will effectively change the pattern itself. The highest RAS value that produces good results without sacrificing cut quality is usually the optimal value.
As you increase the RAS setting ,your motion will become smoother because the RAS is reducing the amount of jerk in the command. The RAS time will be added to your move time e.g. a 1 second move with a 24ms RAS will yield a move time of 1.024 seconds.
Since the jerk has been reduced and the motion is smoother, you will almost certainly be able to raise your rate of acceleration. Most users find out that their move time is actually shorter when using the RAS, not longer.
Please feel free to email us at support@teknic.com if you have any other questions.
Best regards,
Aaron B.
Is it possible to do this with stepper killer motor type?
Hi Roman,
Yes, Teknic's RAS feature is available in all ClearPath models, including the ClearPath "Stepper
Killer" (SDSK) models.
The "Regular" (R) encoder resolution option of the SDSK models has RAS settings up to 16 ms. The "Enhanced" (E) encoder option has the full selection of RAS (and 8x the commandable encoder resolution),
You can view all of Teknic's SDSK and SDHP models at:
www.teknic.com/products/clearpath-brushless-dc-servo-motors/clearpat,h-sd/all-sd-models/#ppsShowPopUp_100.
Please feel free to contact us directly through support@teknic.com if
you have any other questions!
Best regards,
Aaron B. - Teknic Servo Systems Engineer
👍
wouldn't a pid control work just the same
Hi YUP,
While PID control loops (or PIV for ClearPath) and RAS are both used to improve servo performance, they operate in completely different ways. PID control loops use feedback to proportionally control the servo response. RAS does not change how the servo responds to the command, but instead, modifies the incoming command to reduce jerk and jerk derivative.
If you have additional questions about how RAS can benefit your application, please reach out to Teknic’s support (teknic.com/contact/) or give us a call at 585-784-7454.
Best,
Bradley N. - Teknic OEM Application Engineer