I am excited to announce Blue Trail Engineering’s new SER-20XX series of underwater servos which are depth-rated to 200 meters and are optionally available as a low-cost kit.
SER-2010, $395: 29.0 kgf-cm of torque with a default travel range of ± 70 degrees. Cobalt 3-pin bulkhead connector included. Sold fully assembled and tested.
SER-2020, $495: 34.0 kgf-cm of torque with a default travel range of ± 230 degrees, but programmable for up to ± 3.5 full turns of rotation with position control or continuous rotation with speed control. Brushless motor and magnetic encoder. Cobalt 3-pin bulkhead connector included. Sold fully assembled and tested.
SER-2000, $215: Low-cost kit option that allows users to select and install their own standard-sized R/C servo inside the enclosure – including PWM, CAN, or serial servos – as well as their choice of either a Cobalt bulkhead connector or an inexpensive penetrator. The SER-2000 is shown below unassembled and then assembled with a Blue Robotics WetLink Penetrator:
Also, we often offer discounts to student groups (such as RoboSub or MATE teams). Please contact me at sales@bluetrailengineering.com for further info.
Always exciting to see advancements and refinements in underwater technologies, and reasonably priced depth-rated servos are seemingly few and far between.
I also have used some KST servos with a little bit of modification.
Other ones may fit as well. If you have one that you want to use, let me know and I can make a model of it and put it into my CAD assembly to see if it fits. Of course, this would require a drawing of the servo with dimensions (which most, but not all, manufacturers provide).
We are actually lowering prices on the servos! With increased manufacturing volume and improved testing processes, we’ve been able to cut the prices on all of our servo models.
We have added two new models of Underwater Servos, including one that generates up to 5.4 Nm of torque.
We now offer all of our Underwater Servos with either the standard acetal plastic case rated to 200 meters or a new hard-anodized aluminum lower case that increases the depth rating to 400 meters!
So if you need to actuate anything on your ROV (camera or sonar tilt, water sampling, grabbing or letting go of stuff), check out our servos.
Have you performed usage and watertightness tests during prolonged underwater stays?
I’m developing a 4G/5G remote-controlled ROV that will be permanently submerged (with monthly maintenance), and I want to use your servo for some applications, but I don’t have any information about it from my previous inquiry.
I tested one of our 200-meter-rated servos in a pressure chamber for 2 weeks at 600 psi (about 400 meters equivalent depth) with the servo constantly moving back and forth +/- 60 degrees at an 8-second period (150,000 cycles). Upon disassembly, the servo was dry inside with no evidence of leakage. Obviously, most practical applications won’t see even a fraction of that number of cycles.
Additionally, we test every servo that we sell in a pressure chamber with the servo cycling back and forth, making sure that there is no leakage through any of the seals. We used to do this test in a water-filled pressure chamber, but now we do it in an air-filled pressure chamber where we can detect leakage of air into the servo. This is a far more stringent test because it’s harder to make a seal airtight than to make it watertight (at least in my experience).
We’ve sold about 1500 of these servos, so they are a fairly well-established product. As most people on this forum know, O-ring seals are extremely reliable if they don’t have any hair or lint on them and if the sealing surfaces are not scratched. We’re careful during assembly to avoid these problems, and then test each servo as mentioned above to confirm that the seals are reliable.
I apologize, I believe I explained myself incorrectly in my previous message.
I wanted to express that I couldn’t find information regarding the question I posed at the beginning of my previous message (“Have you performed usage and watertightness tests during prolonged underwater stays?”), not a question I previously asked. I believe it’s a grammatical error on my part, as I’m not an English speaker and I was making a literal translation in my head.
I understand your rigor in testing, and I consider you a serious and reliable company; I’ve followed your products and publications.
However, in my question, I’m referring to a real underwater environment. My concerns center around the growth of calcareous organisms such as coralline algae, barnacles, polychaete worms, algae, etc., that can grow near the O-rings and cause a watertightness failure.
Based on your response, I believe moving the servo regularly would help minimize this impact. But the project I’m working on will be implemented in waters affected by a nutrient-rich upwelling, with abundant microscopic life and many fast-growing organisms like those mentioned above.
That’s why I wanted to know if you or any forum members have conducted long-term use tests in a real underwater environment. Or if, on the other hand, given the servo’s design, you think it’s complicated or unlikely that the growth of these organisms would affect its performance.
OK, I understand now. I’m afraid I don’t have test data in a real environment like you describe. I’m sure some of my customers do, but if so, they have not shared it with me.
I’m not even going to try to guess if the growth of such organisms would cause problems with the seals on the servos. All I can say is that the servos use very typical O ring seals, so I expect them to do as well as your other equipment.
