Modern flight training simulators must be equipped with long stroke six degree-of-freedom motion systems that have high dynamic response. For many years electro-hydraulic actuators in a Stewart platform configuration have been found to best meet the performance requirements. However, valve-controlled actuators are very inefficient leading to a large power consumption, and also the need for a substantial cooling system to remove waste energy (heat) from the hydraulic oil. This paper describes a new design of motion system that uses a controlled brushless motor for each actuator, with power transmission via directly driven pumps to conventional simulator hydraulic cylinders. Accumulators are used to store and later recycle high pressure oil when actuators retract. In this way, power consumption has been dramatically reduced (for example from 45kW to 5kW during one representative motion waveform), while retaining the proven characteristics of the cylinder drive. Power consumption is lower, by a factor of between 2 and 4, than an equivalent all-electric solution. The motion system will be supplied for the first time with Boeing 787 simulators to be delivered in 2008. Design details are given in this paper, together with predicted and measured power consumption during a variety of representative cyclic motions.
|Title of host publication||Fluid Power and Motion Control (FPMC 2008)|
|Place of Publication||UK|
|Publisher||Centre for PTMC|
|Number of pages||13|
|Publication status||Published - Sep 2008|