Three high altitude drop tests of a 33.5 m Ringsail Canopy were conducted in the Fall of 2004 from Ft. Sumner, New Mexico. The deployment conditions were consistent with those expected on Mars when using this parachute in conjunction with the Viking 16.1 m supersonic parachute as part of a two-stage system. A 0.34 million cubic meter helium balloon was used to hoist the test article to 36 km altitude. When the instrumented test article was released, a drogue parachute was static-line deployed. The main deployment was triggered 21 seconds later at Mach 0.54 and 148 Pa. This test series was the first in a program of three test series designed to develop this new parachute system for Mars exploration. This paper describes one method by which an Earth qualification test program for a Mars parachute can be conducted.
In this chapter a full electromechanical model of piezoceramic actuators is presented. This model allows for easy integration of the piezo stack with a structural finite element model (FEM) and includes the flow of energy into and out of the piezo element, which is governed by the transducer constant of the piezo element. Modeling of the piezo stack capacitive hysteresis is achieved using backlash basis functions. The piezo model can also be used to predict the current usage of the PZT which depends on the slew rate of the voltage applied to the PZT. Data from laboratory experiments using a load frame and free response tests is used to estimate the PZT model parameters. In addition, a simplified model of a modulated full bridge strain gauge is derived based on test data which includes the effect of intrinsic bridge imbalance. Sensors of this type are often used with feedback control to linearize the behavior of the device. Taken together, the actuator and sensor model can be used for the development of piezo actuated control algorithms.
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