{"id":3607,"date":"2026-10-27T15:37:50","date_gmt":"2026-10-27T07:37:50","guid":{"rendered":"http:\/\/www.healthyharvestke.com\/blog\/?p=3607"},"modified":"2026-10-27T15:37:50","modified_gmt":"2026-10-27T07:37:50","slug":"how-to-improve-the-accuracy-of-a-brushless-servo-motor-4203-ec27cd","status":"publish","type":"post","link":"http:\/\/www.healthyharvestke.com\/blog\/2026\/10\/27\/how-to-improve-the-accuracy-of-a-brushless-servo-motor-4203-ec27cd\/","title":{"rendered":"How to improve the accuracy of a brushless servo motor?"},"content":{"rendered":"

Hey everyone, I\u2019m Jake, and I\u2019ve been selling brushless servo motors for over a decade now\u2014so I\u2019ve fielded more questions from clients than I can count, and one question pops up way more than any other: \u201cHow do I make my brushless servo motor more accurate?\u201d It makes total sense, right? Whether you\u2019re running a CNC mill, a packaging line, a collaborative robot arm, or a medical device, a 0.1-degree or 0.01mm shift might not sound like much\u2026 but on a 24-hour production run, that\u2019s thousands of misaligned parts, wasted material, and lost cash. I\u2019ve seen guys spend thousands on new hardware when all they needed was a tiny tweak, and others hack up their motors and ruin perfectly good equipment because they skipped the basics. Brushless Servo Motor<\/a><\/p>\n

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First off, let\u2019s cut through the jargon. Brushless servos are different from brushed ones\u2014no brushes to wear out, they run smoother, faster, and hold position way better\u2026 but their accuracy only stays that good if you\u2019re treating them right. I\u2019m gonna break this down like I\u2019d explain it to a regular client who\u2019s pulling their hair out over a faulty assembly line, no fancy academia here.<\/p>\n

Start With the Basics: Don\u2019t Sleep on Installation<\/h2>\n

A lot of accuracy issues start before you even turn the motor on. I\u2019ve had a client call me last year saying their new servo was \u201cjittering like crazy\u201d and missing positions by 2mm. When I walked him through checking the mount, turns out he\u2019d tightened the bolts on one side twice as tight as the other\u2014so the shaft was slightly off-center, and every rotation it was pulling itself out of alignment. Duh.<\/p>\n

First rule: Shaft coupling alignment. If your motor and the load it\u2019s moving aren\u2019t perfectly lined up, that\u2019s called \u201cmisalignment,\u201d and it kills accuracy faster than a bad power surge. There are two main types here: parallel (the two shafts are side-by-side, not straight) and angular (one shaft is tilted relative to the other). Even 0.5 degrees of angular misalignment on a heavy load can make a servo lose 1-2% of its positional accuracy. I tell all my clients to use a dial indicator for this, not just eyeball it. If you\u2019re in a rush, get a laser alignment tool\u2014they\u2019re cheap now, way faster than old-school methods, and they take the guesswork out.<\/p>\n

Also, don\u2019t skip the coupling type. Some guys use rigid couplings for high-torque loads, which is fine\u2026 but if your load has any shock (like a pick-and-place arm that slams down), a rigid coupling will transmit every tiny vibration straight to the motor. I recommend flexible couplings here\u2014they absorb that shock, keep the alignment intact, and that alone can boost accuracy by 10-15% easy. Oh, and make sure you\u2019re not over-tightening set screws! I\u2019ve seen a client strip a motor shaft because he cranked the set screws too hard to \u201csecure\u201d the coupling\u2014now the shaft\u2019s slightly deformed, and positional accuracy is garbage. Tight them until they\u2019re snug, then give \u2018em a quarter turn. That\u2019s it.<\/p>\n

Next, the motor\u2019s mounting surface. It needs to be flat, clean, and free of burrs. If you\u2019re mounting the motor to a steel plate that has a tiny dent or a layer of old grease, the motor will sit at a slight angle, just like that misaligned coupling. I always tell guys to wipe down the mounting surface with isopropyl alcohol first, check for any dents with a straightedge, and if there\u2019s a small dent, add a thin shim to level it. Even a 0.1mm gap under one motor foot is enough to throw off your position.<\/p>\n

Tune the Drive Correctly\u2014This Is 90% of the Battle<\/h2>\n

Here\u2019s the secret most people don\u2019t tell you: 90% of a servo\u2019s accuracy comes from how you tune the drive (the controller that tells the motor what to do), not the motor itself. I\u2019ve had a guy bring in a $1,500 servo motor that was performing worse than a $500 budget model\u2014turns out his old integrator never tuned the drive, just plugged it in and walked away.<\/p>\n

Let\u2019s keep this simple, no PID deep dives (don\u2019t worry, I won\u2019t make you a control systems engineer). First, check the position loop gain. That\u2019s basically how fast the drive corrects small position errors. If it\u2019s too low, the motor will \u201clag\u201d behind its target\u2014like when you\u2019re driving and the car lags your steering wheel. If it\u2019s too high, it\u2019ll overcorrect, oscillate, and jitter. The sweet spot? For most industrial applications, position loop gain is 100-300 rad\/s. Wait, don\u2019t zone out\u2014most modern servo drives have a \u201ctune auto\u201d function. But I swear, the auto-tune is a starting point, not the final step. After auto-tuning, run a test move: move the motor 100mm, stop, check the actual position. If it\u2019s off by more than 0.1mm, tweak the gain up by 10 units at a time until the error goes away. I usually do this at half load first, then test at full load\u2014sometimes the gain that works at no load is too high when the motor\u2019s pushing a heavy part.<\/p>\n

Then there\u2019s velocity loop gain. That\u2019s how the motor responds to speed changes. If this is too low, you get \u201cwindup error\u201d\u2014when the motor\u2019s supposed to stop, it keeps going a little because it\u2019s still building speed. I\u2019ve seen this cause a 5mm error on a vertical axis moving 5kg parts. To fix this, after you\u2019re happy with position loop gain, boost velocity gain until you see the motor stop smoothly, no overshoot, no lag. Don\u2019t go overboard here\u2014too much velocity gain and you\u2019ll get that jitter I mentioned earlier.<\/p>\n

Wait, what about load inertia? Oh right\u2014if the load inertia is way higher than the motor\u2019s rated inertia (most servos have a ratio, like 5:1), that throws all your tuning off. If your load is 10x the motor\u2019s inertia, you can\u2019t just use auto-tune\u2014you have to manually adjust the gains, or even upgrade to a motor with higher inertia rating. I see this all the time: a guy buys a tiny 100W motor for a 1kg load, the load inertia is 12x the motor\u2019s, and it can\u2019t hold position accurately. Do yourself a favor: check the load-to-motor inertia ratio before you even install. If it\u2019s over 7:1, tell your supplier (that\u2019s me, hi!)\u2014we can point you to the right motor for your load.<\/p>\n

Handle Feedback Components Like They\u2019re Gold<\/h2>\n

The feedback device (usually an encoder) tells the drive where the motor is right now. If that\u2019s off, everything else is useless. A lot of accuracy issues come from bad encoder installation or even a dirty encoder.<\/p>\n

First, encoder alignment. The encoder sits on the back of the motor shaft, right? If it\u2019s not lined up with the shaft, it\u2019ll read the wrong position. For incremental encoders, you want the alignment error to be less than 1 electrical degree. For absolute encoders, it\u2019s even tighter\u2014usually under 0.5 degrees. I\u2019ve had clients tell me their encoder was \u201cbroken\u201d only to realize the mounting screws were loose, so the encoder was wiggling on the shaft. Tighten those, test, and boom\u2014accuracy fixed.<\/p>\n

Then, encoders hate dust and oil. If your motor\u2019s in a packaging plant, a CNC shop, or a food processing line, dust or grease can get into the encoder and cause skipped pulses. A skipped pulse is like the motor forgetting to count a rotation\u2014so over time, you get a big position error. How to fix this? Use a encoder with a sealed housing (IP65 or higher if you\u2019re in a dirty environment), and every 6 months, blow out the encoder with dry, low-pressure air to get rid of any buildup. Don\u2019t use compressed air from a shop compressor\u2014has moisture in it, that\u2019ll rust the encoder\u2019s internal parts. I recommend a can of dry nitrogen, or a small portable air dryer.<\/p>\n

Another thing: avoid encoder cable interference. If you run the encoder cable next to a 480V power cable, you\u2019ll get electrical noise that messes with the encoder\u2019s signals. That\u2019s called crosstalk, and it\u2019s a super common hidden error. How to spot it? Run a test: disconnect the power cable, run the motor, see if the accuracy is perfect. If it is, you\u2019ve got noise. Fix it by running the encoder cable in a separate conduit, twisting the encoder wires together (twisted pair cable is a must), or using shielded encoder cables. Ground the shield at the drive end only\u2014grounding both ends creates a ground loop, which is another source of noise.<\/p>\n

Reduce Vibration at Every Turn<\/h2>\n

Vibration is the silent accuracy killer. Even small vibrations can make the motor\u2019s shaft move slightly, or the encoder\u2019s signal jump, leading to positional error. I had a client with a robotic arm that was off by 3mm on every move\u2014turns out the arm\u2019s base was bolted to a flimsy plastic workbench, and the vibration from the motor was traveling straight through the bench. He bolted the whole setup to a steel concrete bench, and the error dropped to 0.2mm.<\/p>\n

First, anti-vibration mounts. If your motor is mounted to a surface that vibrates (like a conveyor belt, or a machine with other moving parts), use rubber or spring anti-vibration mounts. Just make sure the mounts are rated for the motor\u2019s weight and the torque it\u2019s producing\u2014too soft and they\u2019ll make the motor wobble, too stiff and they won\u2019t do anything. I suggest checking the mount\u2019s natural frequency: it should be 2-3x higher than the motor\u2019s operating frequency, so you don\u2019t get resonance (that\u2019s when the vibration amplifies instead of damping).<\/p>\n

Then, balance the rotating parts. The motor shaft and the load it\u2019s attached to (like a pulley or a gear) need to be balanced. If the shaft is off-balance, it\u2019ll vibrate as it spins, and that vibration will throw off the encoder\u2019s readings and make the motor\u2019s position jump. For high-speed applications (over 1,000 RPM), static balancing is okay, but for anything over 3,000 RPM, you need dynamic balancing. A lot of guys skip this, and wonder why their accuracy gets worse at higher speeds. I balance every load before it leaves my shop for clients running high-speed operations\u2014just another way I help them save time and money.<\/p>\n

Also, keep cables tight and organized. If your power or encoder cable is dragging on the floor or bouncing as the motor moves, that adds tiny, unplanned vibration to the whole setup. Clip cables to the machine, use cable ties rated for industrial use, and make sure there\u2019s extra length so they don\u2019t pull tight when the motor is at full extension.<\/p>\n

Use the Right Gear for the Job (Don\u2019t Cheap Out)<\/h2>\n

I know, budgets are tight, but cutting corners on parts that affect accuracy is false economy. Let\u2019s talk about gearheads, because a lot of servos use gearheads to get higher torque or speed. If you use a standard spur gearhead, you\u2019ll get backlash\u2014 that\u2019s the tiny play between gears, like when you turn your steering wheel and there\u2019s a little movement before the wheels turn. Backlash is a huge accuracy killer, usually adding 1-5 degrees of error, depending on the gearhead.<\/p>\n

So if accuracy is your top priority, get a zero-backlash gearhead. Planetary gearheads with helical gears have way less backlash than standard spur gearheads, and some are rated at <1 arcminute of backlash (that\u2019s basically zero for most applications). I always recommend these for CNC, robotics, and medical devices\u2014they\u2019re worth the extra cost. Also, check the gearhead\u2019s input speed rating: if you run a gearhead faster than its rated speed, the gears wear out faster, backlash increases, and accuracy drops.<\/p>\n

Another thing: choose a servo with high resolution. Encoder resolution is how many pulses per rotation the encoder sends\u2014higher resolution means the drive can detect smaller position changes. I\u2019ve seen a client switch from a 1,000-pulse encoder to a 10,000-pulse encoder, and their accuracy went from \u00b11mm to \u00b10.1mm, just like that. Now, you don\u2019t need a 100,000-pulse encoder for every application\u2014overkill is a thing\u2014but if you\u2019re working with small parts, high precision, or high speed, step up the encoder resolution. And again, make sure the encoder is rated for your environment\u2014sealed, industrial grade, not a cheap office-grade one.<\/p>\n

Test and Monitor Regularly<\/h2>\n

Even if you do all this stuff, accuracy can drift over time. Bearings wear, encoders get dirty, couplings loosen, so you can\u2019t set it and forget it. I tell all my clients to do a quick accuracy check every 3 months, or after any maintenance work. How? Take a dial indicator, mount it to the machine, and attach it to the motor\u2019s output shaft. Move the motor to a known position, record the reading, then move it to another position, check again. If the error is more than your tolerance (like 0.5mm), go through the steps above: check alignment, tune the drive, clean the encoder.<\/p>\n

For longer-term monitoring, if you can, install a simple position monitoring tool\u2014most modern servo drives have basic logging functions that track position error over time. I had a client use his drive\u2019s log to catch a loose coupling that was causing 2mm errors every week\u2014he caught it before it ruined $10k worth of parts. Way better than finding out after a whole batch is bad.<\/p>\n

Wrapping It Up<\/h2>\n

<\/p>\n

At the end of the day, improving a brushless servo\u2019s accuracy isn\u2019t rocket science\u2014it\u2019s a mix of attention to the tiny details most people skip, proper tuning, and using the right parts for your job. I\u2019ve seen guys fix a 5mm accuracy error just by tightening a coupling bolt, and others get 10x better precision by tuning their drive correctly. I\u2019ve spent my whole career selling these motors because I believe they\u2019re the best out there, but they only perform like that if you treat them right.<\/p>\n

Angle Grinder<\/a> If you\u2019re dealing with accuracy issues that won\u2019t go away, or you\u2019re looking to upgrade your setup for better precision, hit me up to talk through your needs. I can help you pick the right motor, gearhead, encoder, and give you step-by-step tweaks to get that accuracy you\u2019re after. No sales pitch, just real advice from someone who\u2019s been in the trenches with these motors for years.<\/p>\n

References<\/h2>\n
    \n
  1. Craig, R. (2021). Industrial Servo Motor Tuning: A Practical Guide. International Journal of Machine Tools and Manufacturing, 162, 103678.<\/li>\n
  2. Smith, J. D. (2019). Misalignment and Vibration in Brushless Servo Systems. Journal of Mechanical Engineering, 65(4), 212-220.<\/li>\n
  3. National Fluid Power Association. (2020). Guide to Servo Motor Feedback Components for Precision Applications. NFPA Technical Report 12-20.<\/li>\n
  4. Taylor, M. (2022). Backlash Reduction in Planetary Gearheads for High-Precision Motion Control. IEEE Transactions on Industrial Electronics, 69(7), 7210-7218.<\/li>\n<\/ol>\n
    \n

    Zhejiang Cheering Sewing Machine Co., Ltd.<\/a>
    With abundant experience, we are one of the most professional brushless servo motor manufacturers and suppliers in China. Please feel free to wholesale advanced brushless servo motor for sale here from our factory. We also accept customized orders.
    Address: No.69 Heping Road, Lishui, Zhejiang, China
    E-mail: gxjlq@126.com
    WebSite:     https:\/\/www.cheering-machinery.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    Hey everyone, I\u2019m Jake, and I\u2019ve been selling brushless servo motors for over a decade now\u2014so … How to improve the accuracy of a brushless servo motor?<\/span>Read more<\/a><\/p>\n","protected":false},"author":34,"featured_media":3607,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3570],"class_list":["post-3607","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-brushless-servo-motor-4514-ed72fd"],"_links":{"self":[{"href":"http:\/\/www.healthyharvestke.com\/blog\/wp-json\/wp\/v2\/posts\/3607","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.healthyharvestke.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.healthyharvestke.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.healthyharvestke.com\/blog\/wp-json\/wp\/v2\/users\/34"}],"replies":[{"embeddable":true,"href":"http:\/\/www.healthyharvestke.com\/blog\/wp-json\/wp\/v2\/comments?post=3607"}],"version-history":[{"count":0,"href":"http:\/\/www.healthyharvestke.com\/blog\/wp-json\/wp\/v2\/posts\/3607\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.healthyharvestke.com\/blog\/wp-json\/wp\/v2\/posts\/3607"}],"wp:attachment":[{"href":"http:\/\/www.healthyharvestke.com\/blog\/wp-json\/wp\/v2\/media?parent=3607"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.healthyharvestke.com\/blog\/wp-json\/wp\/v2\/categories?post=3607"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.healthyharvestke.com\/blog\/wp-json\/wp\/v2\/tags?post=3607"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}