Abstract: The subject matter of this specification can be embodied in, among other things, a method for determining health of an actuator that includes applying power to an actuator operating in a nominal operational state, capturing a first signal representative of actuator movement or actuator position, capturing a second signal representative of total actuator force, determining, based on the first signal, an inertial force value representative of force used to overcome at least one of inertia of the actuator and inertia of a load on the actuator, determining, based on the inertial force value and the captured second signal, a load force value representative of actuator force used to overcome force of the load and friction of the load, determining a health value of the actuator based on the load force value, and providing an indication of health of at least one of the actuator and the load.

Abstract: The subject matter of this specification can be embodied in, among other things, an electrohydraulic positioning control system that includes a shuttle valve configured to direct fluid flow between a selectable one of a first fluid port and a second fluid port, and a fluid outlet configured to be fluidically connected to a fluid actuator, a first servo valve controllable to selectably permit and block flow between the first fluid port, a fluid source, and a fluid drain, a second servo valve controllable to selectably permit and block flow between the second fluid port, the fluid source, and the fluid drain, a first servo controller configured to provide a first health signal and control the first servo valve based on a second health signal, and a second servo controller configured to provide the second health signal and control the second servo valve based on the first health signal.

Abstract: The subject matter of this specification can be embodied in, among other things, an electric actuator driver that includes a first input port configured to receive an analog electrical servo control signal, a second input port configured to receive a position feedback signal, a first output port, a second output port, and a conversion circuit configured to determine one or more electric motor coil control current levels based on the analog electrical servo control signal and the position feedback signal, provide the one or more electric motor coil control currents based on the determined electric motor coil control current levels at the first output port, determine a feedback signal based on the analog electrical servo control signal, and provide the determined feedback signal at the second output port.

Abstract: The subject matter of this specification can be embodied in, among other things, an electric actuator driver that includes a first input port configured to receive an analog electrical servo control signal, a second input port configured to receive a position feedback signal, a first output port, a second output port, and a conversion circuit configured to determine one or more electric motor coil control current levels based on the analog electrical servo control signal and the position feedback signal, provide the one or more electric motor coil control currents based on the determined electric motor coil control current levels at the first output port, determine a feedback signal based on the analog electrical servo control signal, and provide the determined feedback signal at the second output port.

Abstract: The subject matter of this specification can be embodied in, among other things, an electrohydraulic positioning control system that includes a shuttle valve configured to direct fluid flow between a selectable one of a first fluid port and a second fluid port, and a fluid outlet configured to be fluidically connected to a fluid actuator, a first servo valve controllable to selectably permit and block flow between the first fluid port, a fluid source, and a fluid drain, a second servo valve controllable to selectably permit and block flow between the second fluid port, the fluid source, and the fluid drain, a first servo controller configured to provide a first health signal and control the first servo valve based on a second health signal, and a second servo controller configured to provide the second health signal and control the second servo valve based on the first health signal.

Abstract: Systems and methods to determine conditions of a diesel particulate filter (DPF) based on correlation between predicted and actual thermal data of the fluid exiting a DPF are provided. Soot loading, ash loading, and/or DPF damage may be detected, and DPF operational models may be calibrated in accordance with such systems and methods. Further, initiation of regeneration may also be effected in accordance with such systems and methods.

Abstract: A method to automatically identify the inertia of an actuator (and the like) and load for tuning an observer-based controller is presented. The tuning is a one-time process that is initiated by a user when the actuator is installed. The control includes a model of the actuator with state feedback to set the desired dynamics.

Abstract: A method to automatically identify the inertia of an actuator (and the like) and load for tuning an observer-based controller is presented. The tuning is a one-time process that is initiated by a user when the actuator is installed. The control includes a model of the actuator with state feedback to set the desired dynamics.

Abstract: A fuel metering unit for an aircraft gas turbine engine having both electronic and manual control, both compensated for altitude variations. A three-dimensional cam is used to control the position of a fuel metering valve. One axis of the 3-D cam is electronically controlled and another is mechanically controlled. Electronic control is the normal mode and sets the electronic axis to provide a fuel metering valve setting which delivers a mass flow rate to the engine as demanded by the position of the fuel lever as interpreted by the electronic control. Upon failure of the electronic control, the position of the 3-D cam along the electronic axis is mechanically locked so that any further changes in fuel metering valve position are a function solely of the position of the power lever as translated to the mechanical axis of the 3-D cam. Transfer from electronic to manual control is therefore "bumpless.

Abstract: A fuel metering unit for an aircraft gas turbine engine has both electronic and manual control, both compensated for altitude variations. A three-dimensional cam is used to control the position of a fuel metering valve. One axis of the 3-D cam is electronically controlled and another is mechanically controlled. Electronic control is the normal mode and sets the electronic axis to provide a fuel metering valve setting which delivers a mass flow rate to the engine as demanded by the position of the fuel lever as interpreted by the electronic control. Upon failure of the electronic control, the position of the 3-D cam along the electronic axis is mechanically locked so that any further changes in fuel metering valve position are a function solely of the position of the power lever as translated to the mechanical axis of the 3-D cam. Transfer from electronic to manual control is therefore "bumpless.