Experimental new suspension system for Strykers

Active Damper Suspension System Demonstrates Dramatic Mobility Improvements

A reader tips me off to this. The story is from February and reports on January tests of a new computer-controlled suspension that hopes to greatly improve the control, speed, and ride of Stryker LAVs.

The core of the system tested is 8 dampers & controllers using proprietary algorithms to modulate individual wheel forces within 4 milliseconds in response to terrain inputs and body motion. MillenWorks engineers retained full functionality of the stock Stryker vehicle’s pressurized gas spring & ride height management system while integrating the electrically controllable MR technology into the physical envelope of the original damper.

“The stock vehicle utilizes a very capable suspension load-leveling system, and it was a good challenge to ensure we didn’t lose that important functionality in the process of incorporating our controllable damper,” noted Project Manager Peter LeNoach. “The net result is a high-performance suspension system that is bolt-on retofittable, simple, with operation that is completely transparent to the vehicle and its operator.”

The system is called Magneto-Rheological Active Damper Suspension (MROADS) and is built by Millenworks. The tests were apparently pretty successful.

Mobility gains measured during comparison testing showed great promise for Strykers that could be retrofitted with this system in the future. Over a range of off-road bump courses, the MillenWorks MROADS Stryker was 40-60% faster than the stock vehicle at the same level of driver absorbed power; a measure of transmitted vibration. The MROADS Stryker’s best performance was a 72% increase in the vehicle’s 6-watt absorbed power speed, from 22 mph (stock) to 38 mph. Increases in vehicle platform stability were immediately obvious to drivers and bystanders. The system also showed marked improvements during aggressive on-road maneuvers like lane changes. The maximum lane change speed increased from 38 mph (stock) to over 50 mph with the MillenWorks MROADS system.

This program has been going on for four years.


  1. I’d love to see what this system would do to an M1 or M2 :) Faster cross-country tanks anyone? It would probably also bump up road speed a little too.

  2. James: Thanks. When I was reading this I wondered if it was similar to those systems in consumer cars. I didn’t guess that it was the same thing.

  3. Murdoc: No problem, I live only to make you smile. This technology is making some big waves in a lot of fields. One area that may interest you, is the use of Magneto-Rheological dampeners as anti-recoil devices. The apache 30mm gun is being adapted to use these dampeners. If fuel cell tech continues its rapid pace, incorporating Magneto-Rheological dampeners in to man portable weapons is not far away. Nicholas: This system does not increase the speed of a vehicle. It does, allow better control of a vehical over its possible speed range. Thus a Striker could always go 50 mph, it just may be uncontrollable at that speed, so this system adds a measure of control. M1 & M2’s are speed limited by engine governors and not by control limitations impossed by its suspension system. You could get an M1 tank to do 70 mph, of course the tracks would fly off … but you would get a cool rising sun headband..

  4. I was under the impression the main reason for the speed limitation in an M1 is that it shook up the driver too badly. That’s why I was thinking this suspension would allow you to increase the speed. Smoother ride would allow you to comfortably travel at higher speed. As far as I know (from what I have read), this issue is typically what limits the speed of tracked vehicles. No good getting there fast if you shake the brains of the occupants into mush while doing so…

  5. Nicholas: When you are trying to determine the speed of a tracked vehicle the equations can make you want to take up bomb disposal as a hobby. For example, to determine the maximum speed a M1 tank can go, you need to determine the the Mobility factor of the vehicle (MI) as compared to the sheer strength of the ground supporting the M1. Through the whole mizture into a computer and it will spit out the M1 tanks maximum speed on a given terrain. The match details can be found:http://www.me.vt.edu/AVDL/journal_publications/2003%20GTMVC%20-%20Dynamic%20Performance%20and%20Mobility Details on the M1 track System: https://www.logsa.army.mil/pub/psissuesA/PS_618/618-02-08.pdf MI = [(Contact Pressure Factor*Weight Factor)/(Track Factor*Grouser Factor) + Bogie Factor – Clearance Factor] *Engine Factor *Transmission Factor where: Contact Pressure Factor = Gross Weight_lb/Ground Contact Area_square inches Weight Factor = 1.0 to 1.8 depending on Gross Weigh Track Factor = Track Width in inches/100 Grouser Factor = 1.0 or 1.1 depending on Grouser Height Bogie Factor = Gross Weight in lb/10 /Area on One Track Shoe square inches /Total Number of Bogies on Track in Contact with Ground Clearance Factor = Clearance in inches/10 Engine Factor = 1.0 or 1.05 depending on ratio of Engine HP to Vehicle Weight Transmission Factor = 1.0 if automatic or = 1.05 if manual

  6. But that does not determine how bumped up the driver will be. The equation does not take into account too many things, notably the incline of the terrain, or even the damping factor of existing suspension. This equation in my eyes is too basic for any comparison worth noting. If someone here wants to learn how this all works, you need to start reading books on stability of mechanical systems, starting with simple spring systems with periodic forcing. Don’t worry it’s not too complex a subject, and there are plenty of books out there.

  7. Vstess: You are correct. All the equation will tell you is what is the maximum speed the vehical can go in a particular terrain. Once you know the maximum speed a vehical can go, compare that speed against the speeds allowed for the vehical. The difference will tell you if an improvement in the suspension system is even worth investigating.