Top of the range flight simulators not only provide the pilot in training with realistic controls and visual displays, but with the physical experience of flying an aeroplane as well. Pilots need to adjust to the feelings of descent, turbulence and ascent in order to respond to this feedback in a real life situation and until recently, all professional flight simulators used electrohydraulic actuators to achieve the movements that mimic those flying conditions. In the past two years, the development of all-electric actuators has driven the hydraulic systems out of the market for flight simulation, as the cost of maintenance and replacement was becoming too high when alternative technologies could be cheaper.
Of course, many flight simulators that were built before the general shift in technology still use hydraulics to create the motion, as the systems can handle a range of payloads without adaptations being made to valves. This is not the case with electric actuators, so engineers had to address this problem before hydraulic technology could be replaced efficiently in flight simulators. In solving the payload problems associated with using electric actuators, the engineers developed a system that drew less power than the original electrohydraulic one, while being quieter and more efficient; a bad day for hydraulics, perhaps, but a good day for the progression of technology and the environment.
Earthquake simulators, also known as shaking tables, are another type of simulator that uses hydraulic actuators to mimic the motions of an earthquake. Most of these are in universities and research laboratories and are used to test the seismic performance of buildings and other structures that will be built in earthquake prone areas. There is one at the Natural History Museum in London, should any readers wish to test their mettle when faced with a recreation of the 6.8 strength quake in Kobe, Japan, in 1995. These pieces of equipment use hydraulics to move the surface back and forth violently, and need to be accurate enough in their movements, that through a combination of back and forth or side to side movements at different speeds, the table can be calibrated to accurately reproduce the effects of any magnitude of earthquake.
As shaking tables are found at visitor attractions as well as in test laboratories, they need to be able to handle a large amount of weight, far more than the average flight simulator. For this reason, hydraulics are uniquely suited to the purpose, and fully electric actuators would be susceptible to breaking under the strain of a whole class of children on a school visit, or a prototype building material or method for quake-prone areas.
Another area where hydraulic power still reigns supreme is the bucking bronco bar challenge game, although actually it is the professional level models that still use hydraulics, the cheaper alternatives for a bit of fun are starting to make use of electric actuators, as they are cheaper to buy and maintain.
Rodeo cowboys use the bucking bulls as a training method in preparation for big events as it is much safer than riding the real thing, and this feat of endurance is what has made the challenge so appealing to the public, hence the proliferation of these items in bars and theme parks around the country. Some of the rodeo training bulls found in leisure attractions may use hydraulics still, and they are the power source of choice for the professional market, as electric actuators do not have quite the same force as a hydraulic one, and a faithful representation of the power of a real bull is very important for a rodeo cowboy in training. There is still plenty of room for hydraulics in simulators, even if the fully electric technology is finally catching up.