Bias correcting phase compensating rate limiter

A flight control system, comprising:

• a member to control flight of an aircraft;
• an actuator to control movement of the member;
• and
• a bias correcting phase compensating rate limiter to control movement of the actuator, wherein the bias correcting phase compensating rate limiter comprises a switching arrangement adapted to reverse a polarity of an error signal in response to a set of predetermined conditions, the set of predetermined conditions comprising:
• a commanded rate of movement exceeding a rate limit capability of the actuator;
• a time rate of change of an input signal to the rate limiter being opposite in polarity to a difference between the input signal to the rate limiter and an output signal from the rate limiter;
• and
• a time rate of change of the input signal to the rate limiter being opposite in polarity to a difference between the output signal from the rate limiter and a signal corresponding to a pre-specified neutral or trim position of the actuator.

A method to control movement of a device, comprising:

• limiting a time rate of change of a device control signal;
• substantially avoiding any phase loss in limiting the time rate of change of the device control signal;
• substantially correcting for any bias in limiting the time rate of change of the device control signal;
• and
• reversing a polarity of an error signal to substantially avoid any phase loss in limiting the time rate of change of the device control signal and to substantially correct for any bias in limiting the time rate of change of the device control signal, wherein the polarity of the error signal is reversed in response to a set of predetermined conditions, the set of predetermined conditions comprising:
• detecting a commanded rate of movement of the device exceeding a rate limit capability of the device;
• detecting a time rate of change of an input signal to a rate limiter being opposite in polarity to a difference between the input signal to the rate limiter and the output signal from the rate limiter;
• and
• detecting a time rate of change of the input signal to the rate limiter being opposite in polarity to a difference between the output signal from the rate limiter and a signal corresponding to a pre-specified neutral or trim position of the device.

A method to control an aircraft, comprising:

• controlling movement of an actuator;
• limiting a time rate of change of an actuator control signal using a rate limiter;
• substantially avoiding any phase loss in the rate limiter;
• and
• substantially correcting for any bias between an input signal to the rate limiter and an output signal of the rate limiter
• reversing a polarity of an error signal to substantially avoid any phase loss in the rate limiter and to substantially correct for any bias between the input signal to the rate limiter and the output signal of the rate limiter, wherein the polarity of the error signal is reversed in response to a set of predetermined conditions comprising:
• a commanded rate of movement of the actuator exceeding a rate limit capability of the actuator;
• a time rate of change of an input signal to the rate limiter being opposite in polarity to a difference between the input signal to the rate limiter and the output signal from the rate limiter;
• and
• a time rate of change of the input signal to the rate limiter being opposite in polarity to a difference between the output signal from the rate limiter and a signal corresponding to a pre-specified neutral or trim position of the actuator.

A computer program product to control movement of a device, the computer program product comprising:

• a computer usable medium having computer usable program code embodied therein, the computer usable medium comprising:
• computer usable program code configured to limit a time rate of change of a device control signal;
• computer usable program code configured to substantially avoid any phase loss in limiting the time rate of change of the device control signal;
• computer usable program code configured to substantially correct for any bias in limiting the time rate of change of the device control signal;
• and
• computer usable program code configured to reverse a polarity of an error signal in response to a set of predetermined conditions to substantially avoid any phase loss in limiting the time rate of change of the device control signal and to substantially correct for any bias in limiting the time rate of change of the device control signal, the set of predetermined conditions including a commanded rate of movement exceeding a rate limit capability of the device;
• a time rate of change of an input signal to a rate limiter being opposite in polarity to a difference between the input signal to the rate limiter and an output signal from the rate limiter;
• and a time rate of change of the input signal to the rate limiter being opposite in polarity to a difference between the output signal from the rate limiter and a signal corresponding to a pre-specified neutral or trim position of the device.