Hi, I’m looking for a really high torque, fast servo with the following performance specs and I’m stuck. Can anyone suggest a product out there? Or should I be looking in a different place e.g. industrial applications? It does need to operate off a battery.
Torque: 150+ kg-cm
Speed: approx 0.2 seconds / 60 degrees
Range: 180 degrees
Thanks,
Tom
Hi @tommorganonline and welcome to the forum!
Could this item do your work?
For 14.8 Volts:
Can we know what are you building?
In order to get high speed and high torque, you will have high power requirements, and high cost because the unit has to be very strong and quick at the same time. If I knew more about the application, maybe I could suggest other options. Is the application only moving between two or three discrete positions? or does it need to be able to move freely over a large range and stop anywhere instantly, and accurately? Can the accuracy be finetuned once it gets to the approximate location? This would separate the need for super strength and quick motion from the positioning accuracy. Is the application something that could be dynamic. Maybe a constantly moving actuator that is always rotating and then fires at a specific position to accomplish the need task at a specific position. Is it a rotary or linear application. Many high torque systems choose to use air cylinders to give motion quickly with considerable strength. The accuracy is a little harder, but it is still expensive. I hope I have given you some ideas that may lead to a solution.
Hi, thanks for the response. I’m building a self balancing platform for a person and the servo needs to keep the platform level in response to gyro / accelerometer signal. The nature of the mechanism requires a rotational servo that drives gear / belt set up. As such both speed and torque are required, precision is important but only to nearest 1-2 degrees. Space and weight also important. The 110kg-cm servo here is an improvement on the current 74kg-cm model I’m using but it would be good to know if this is the highest torque available at those speeds? Also, what is the trend in servo performance improvement? Can I expect higher torques at lower prices to be available in 6-12 months time? Thanks!
FYI it will be a mobile device and so I presume not compatible with air cylinders? 
When working with large loads and balancing them, using gravity to your advantage can significantly reduce the power requirements needed by your equipment. Let me give an example to explain my point. If you stand on a curb, you are constantly exerting muscle power to maintain your balance, but if you are hanging from a rope, you don’t have to exert any effort to keep yourself upright. If you are in a rotating holder with more than half of your weight below the pivot point, gravity will keep you upright. If the pivot point is at the bottom of the holder, gravity will constantly be working to flip you upside down and it will take a lot of power or effort to keep yourself upright. If you can have the balance point be above the center of gravity of the object you are keeping balanced, then gravity will do all the work for you.
So, if you have a two wheel self balancing vehicle with 10" wheels, your pivoting point is 5" above the ground. If it has 24" wheels, the pivot point is 12" above the ground. If you have a person of 6’ height standing on a platform with 1" of ground clearance, then the center of mass is approximately 37" above the ground. With the 10" wheels, the center of mass is 32" above the pivot point, but only 25" above the pivot point of the 24" wheels. In this example the larger wheels will reduce the needed energy to balance the load by almost 22% (25/32=0.78125). With wheels larger than 74" in diameter, gravity would do the work for you. I expect that a wheel diameter of over 6’ will not be practical, but finding a balance point as high as possible will make balancing as easy as possible. If your person where to sit down, thus reducing their center of gravity to 24" from the surface of the ground, would make the 24" wheels 36.8% (12/19=0.6316) more effective than the 10" wheels.
I hope this discussion is helpful for the design of your project.
Using larger wheels also means that the center of gravity must shift forward or backward farther to generate the same potential energy to cause the wheels to begin rolling. This results in a smaller correction angle being needed to compensate for balance when using larger wheels. It is easier to explain this concept with a drawing… far easier than using words.
I edited the last comment and added the drawing. Sorry it is just hand drawn, but I have spent way too much time on this already… good luck with your project.
Thank you for the thoughtful responses and wonderful drawing 
Should anyone have any further thoughts on high torque servos please share. Thanks!
Perhaps there is something here Robotis AX Series DYNAMIXEL Robot Servos
http://www.robotis.us/dynamixel/
They have a large powerful range of servos.
The really good thing is one can get the current position of the servos. This is a feature missing on most of the servos
one can buy today - which is mmn is a huge deficit.
