Abstract: A high-capacity low-profile load cell for measuring compression force. The load cell comprises a support ring, a diaphragm supported by the support ring, and first and second pluralities of strain gages arranged under the diaphragm for detecting strain produced by application of a load from above. The diaphragm comprises a slug portion and a plate portion that surrounds and supports the slug portion. The slug portion has a height greater than a thickness of the plate portion. The first plurality of strain gages is disposed on a bottom surface of the slug portion, while the second plurality of strain gages is disposed on a bottom surface of the plate portion. These strain gages are electrically connected to form a Wheatstone bridge.

Abstract: A method for reducing force and position control tracking errors caused by changes in hydraulic pressure at the actuator ports of a hydraulic servo valve. The method may use either the force command signal or the load cell signal in conjunction with a mathematical algorithm to compensate for changes in the flow capacity in the servo valve caused by changes in pressure at its ports. Good performance can be attained using the load cell signal. Alternatively, the algorithm can use the force command signal. The performance of the control loop with proper velocity feed-forward compensation keeps the feedback signal largely in phase with the command. Pressure sensors for detecting pressure changes at the actuator ports of the servo valve are not required for load droop compensation.

Abstract: A controlled system (480) for application of force on a test object includes a force actuator (484) that is coupled to and applies a force on the test object. A velocity signal generator (482) is in a feedforward configuration relative to the force actuator (484) and generates a velocity signal (503) that is predictive of the velocity of the test object. A controller (482) is coupled to the force actuator (484) and to the velocity signal generator (482) and generates a desired applied force signal (546) compensated by the velocity signal (503).

Abstract: A force control system (50, 300) for actuation of a test object (54, 304) includes a force actuator (52, 356) that is coupled to and applies a force on the test object (54, 304). A velocity signal generator (124, 310) is in a feedback configuration relative to the force actuator and generates a velocity signal (150, 324) that is indicative of the velocity of the test object (54, 304). A controller (62, 302) is coupled to the force actuator (52, 356) and to the velocity signal generator (124, 310) and generates a desired applied force signal (130, 380) compensated by the velocity signal (150, 324).

Abstract: A system remotely collects test data from a test platform using platform attached sensors. Identification chips, each having a unique identification code, are each paired with an associated sensor to form sensor/chip pairs. At least one patch panel having a plurality of connections is positioned approximate to the platform. Connections are communicatively linked to each of the sensor/chip pairs. A computer system is communicatively linked to additional patch panel connections. The identification of selected sensors is queried by a computer command to the patch panels, and a group of sensors for a given test is identified and selected. Test data from each of the selected sensors is transferred through the patch panels to the computer system for collation and generation of a test setup compatible with a data acquisition system. Test setup information is downloaded to the data acquisition system in preparation for the next test.

Abstract: A system remotely collects test data from a test platform using platform attached sensors. Identification chips, each having a unique identification code, are each paired with an associated sensor to form sensor/chip pairs. At least one patch panel having a plurality of connections is positioned approximate to the platform. Connections are communicatively linked to each of the sensor/chip pairs. A computer system is communicatively linked to additional patch panel connections. The identification of selected sensors is queried by a computer command to the patch panels, and a group of sensors for a given test is identified and selected. Test data from each of the selected sensors is transferred through the patch panels to the computer system for collation and generation of a test setup compatible with a data acquisition system. Test setup information is downloaded to the data acquisition system in preparation for the next test.