House of Dancing Water Hydraulics
Greg Paddock, Hydraulic Territory Manager, at Parker Hannifin Corporation's Hydraulics Group explains below the critical role hydrulics played in the stage's motion control system.The design and component selection for the HPU was critical with regard to the overall success of the project. The HPU had to be capable of providing smooth, ripple free flow without response lag whether there was motion demand from only one of the small vomitory stages, or from all of the large main stages working in unison. Fourteen Parker PV270 variable volume piston pumps responded precisely to any system flow demand regardless of the magnitude and rate of the motion profile required by the stages collectively, or independently. The PV270’s extremely fast on and off stroke response (< 85 msec & < 75 msec respectively) were key to the stability of the pressure and flow supplied to the servo axis’.
With recommendations on component selection from Parker personnel, Comoso integrated all of the HPU components into a highly engineered HPU with two key design challenges presented to them. One, the electrical power available for the HPU was limited so overall system efficiency was a key design criteria in component selection, and two, the fact that the HPU had to physically fit through a very limited access galley to where the HPU’s would be permanently located. It was decided that the HPU would be designed in a modular configuration with two symmetrical halves and then reconnected once in their final installation location. Mark Force and Matt Schoenbachler of Comoso exceeded everyone’s expectations with the HPU design and layout.
The 32 Parker custom designed and built cylinders where designed specifically in order to accommodate the extreme environmental conditions and challenges of this application which included continuous submersion in chlorinated pool water, load induced side loads on the cylinder rods, and very low friction seals which were necessary to achieve the desired motion profile of the stages. Special coatings, stainless steel rods, a proprietary process to achieve the cylinder rod finish, and special rod and piston seals where necessary to ensure the critical performance of the cylinders.
The Parker D41FH Proportional/servo valves were the final critical elements in the stage motion and control loop. The stability of the D41FH and extremely high dynamic response were key to maintaining the commanded cylinder motion profiles demanded by the director of the show. The stage design did not allow for a mechanical means to ensure that each cylinder would maintain a level position relative to the other three cylinders supporting each corner of the eight stages, therefore each cylinder had to be precisely controlled via electronic magnetostrictive feedback devises, Delta digital motion controllers and Parker D41FH proportional/ servo valves to ensure all of the cylinders on each stage maintained highly precise synchronized motion profiles relative to each other. This required complex external position and velocity loop control as well as a valve capable of carrying out the precise system commands to ensure each cylinder maintained their desired motion profile. A series of dynamic performance calculations were carried out by Parker Hydraulic Systems Engineer, Rich Duder to ensure proper valve selection and sizing as well as predicting overall loop stability. The valves also provided a number of key safety elements which were of paramount importance for the overall system design as there are live actors and support personnel underwater, above and below the stages while the stages are in motion during performances. The D41FH spring centered servo spool with mechanically adjustable bias insured that upon an emergency abort event or power outage the stages would come to a rapid and predictable safe stop without fail. This helped to ensure the safety of all show personnel.
Read more about this and other Entertainment Engineering topics in our online magazine!
Posted by Bruce at 2 Nov 2011 
Categories: Entertainment Engineering
Tags: Greg Paddock Hydraulic Territory Parker Hannifin Corporation Hydraulics Group HPU stage design hydraulic stage Parker PV270 Rich Duder
Categories: Entertainment Engineering
Tags: Greg Paddock Hydraulic Territory Parker Hannifin Corporation Hydraulics Group HPU stage design hydraulic stage Parker PV270 Rich Duder
Comments