Method, apparatus and design procedure for controlling multi-input, multi-output (MIMO) parameter dependent systems using feedback LTI'zation

Computer executable software stored on a computer or processor readable medium, the code for developing control laws for a dynamic device having device characteristics, the code comprising;

• code to transform the device characteristics into a multi-input linear time invariant system;
• code to establish control criteria yielding the device characteristics in the transformed coordinates LTI;
• code to define at least one design point in the multi-input linear time invariant system;
• code to adjust the transformations to corresponding with the design point(s);
• code to develop a physical coordinates control law corresponding to the adjusted transformations;
• and
• code to apply reverse transformations to cover the full design envelope.

A multi-input parameter dependent control system for controlling an aircraft, said system comprising;

• receiving means for receiving a plurality of aircraft status signals and for receiving a plurality of current parameters signals;
• memory having at least one region for storing computer executable code;
• and
• a processor for executing the program code, wherein the program code includes code responsive to:
• (i) transform the aircraft characteristics into a multi-input linear time invariant system;
• (ii) select and apply gain schedules to flight control laws in transformed coordinates, the gain schedules corresponding to the received current parameter signals;
• (iii) determine parameter rates of change, and to apply the parameter rates of change to the flight control laws;
• (iv) apply the received aircraft status signals to the flight control laws;
• (v) convert the transformed coordinates control laws to physical coordinates;
• and (vi) control the aircraft based on the updated flight control laws.

A method of designing control laws for a dynamic device, the device accepting multiple inputs and generating multiple outputs and operating in an environment having varying parameters, characteristics of the device being definable by equations of motion, said method comprising the steps of:

• transforming coordinates for the equations of motion into a linear-time invariant system;
• and
• establishing a closed loop behavior in the linear time invariant system, wherein
• said establishing step generates gain schedules for controlling the equations of motion throughout an operational envelope of the device.

A method of designing control laws for a dynamic device, the device accepting multiple inputs and generating multiple outputs, characteristics of the device being definable by equations of motion, said method comprising the steps of:

• defining an operating envelope including varying parameters throughout the envelope;
• determining control designs for a plurality of discrete points in the envelope;
• transforming the plurality of discrete point designs to a linear time invariant system (z-space) to provide corresponding gains in z-space and interpolating between the gains in z-space to provide linearly blended gains;
• and
• inversely transforming the z-space linearly blended gains to physical space.

A method of designing control laws for a dynamic device, the device accepting multiple inputs and generating multiple outputs, characteristics of the device being defined by at least one control law, said method comprising the steps of:

• determining in physical space gains corresponding to a discrete operating condition, the gains for use in the control law;
• transforming the gains obtained at the discrete operating condition to a linear time invariant system (z-space) and obtaining corresponding gains in z-space;
• and
• inversely transforming the z-space gains into physical space to correspond to a plurality of operating conditions throughout an envelope in which the device operates.

A method of designing control laws for a dynamic device, the device accepting multiple inputs and generating multiple outputs, the device operating in an environment having multiple parameters, said method comprising the steps of:

• defining a control law comprising derivative, proportional and integral gains and device inputs;
• and
• developing gain schedules to be applied to the control law so as to accommodate varying parameters, wherein
• transforming device characteristics into a linear-time invariant system generates the gain schedules and provides a stable closed loop behavior for the transformed characteristics.