Reference Trajectory Generation for Disturbance-Decoupled OBC
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optimization-based control (OBC) systems in industrial automation lack intuitive methods for explicitly defining closed loop responses and do not account for both measured and unmeasured disturbance variables, leading to inefficiencies in controlling constrained multivariable dynamical processes.
Innovation Solution
A method for generating a reference trajectory that includes portions based on closed-loop response to setpoint changes, measured disturbance variables, and unmeasured disturbance variables, using a first-order setpoint filter and state estimation to compensate for deviations and unmeasured disturbances, thereby enhancing control accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard tuning methods with weighting coefficients are used to minimize variations between process outputs and setpoints, then control performance is improved, but the method lacks intuitive definition of closed loop response and does not account for disturbance variables
Solution Approach 1:
The patent transforms the control approach by changing from weighting coefficient tuning to explicit closed-loop response specification. Instead of adjusting abstract weights, the system now directly defines desired response characteristics (rise time, settling time, overshoot) as tuning parameters, making the control behavior intuitive and interpretable while maintaining improved reliability
Solution Approach 2:
The patent introduces a disturbance observer as an intermediary component that estimates unmeasured disturbance variables. This observer acts as a mediator between the controlled process and the controller, providing information about disturbances that would otherwise be unknown, thereby enabling the controller to compensate for them explicitly
2Ease of manufacture
If standard tuning methods are used, then implementation is simple, but the system does not account for measured or unmeasured disturbance variables
Solution Approach 1:
The disturbance observer serves as an intermediary that systematically estimates both measured and unmeasured disturbance variables. This intermediary component bridges the gap between simple implementation and reliable disturbance compensation by providing explicit disturbance estimates that the controller can use without complex manual tuning
Solution Approach 2:
The patent segments the control problem into distinct components: setpoint tracking, measured disturbance compensation, and unmeasured disturbance estimation. Each component is handled separately through specific portions of the reference trajectory, making the overall system more reliable while maintaining implementation clarity
3Adaptability or versatility
If existing OBC methods are used, then control of constrained multivariable processes is achieved, but explicit definition of closed loop response and disturbance variable accounting are lacking
Solution Approach 1:
The disturbance observer acts as an intermediary that recovers lost disturbance variable information. By estimating both measured and unmeasured disturbances, the observer compensates for the information loss inherent in standard OBC methods, enabling explicit disturbance compensation while maintaining adaptability to constrained multivariable processes
Solution Approach 2:
The patent implements feedback through the disturbance observer that continuously monitors process deviations and estimates disturbance variables. This feedback mechanism provides real-time information about disturbances, which is then used to adjust the reference trajectory and maintain optimal control performance for constrained multivariable processes
Data Source
AI summary
Embodiments of this present disclosure include a non-transitory computer readable medium storing instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations including determining a predicted value for a process output representative of controlled operation of one or more industrial automation devices within an industrial automation system, receiving an actual value for the process output from the industrial automation devices, and determining a deviation between the predicted value and the actual value for the process output. Additionally, the operations include generating a first portion of a reference trajectory based on a closed-loop response performance to a change in a setpoint, generating a second portion of the reference trajectory based on a calculated effect from a disturbance variable on the actual value for the process output, and generating a third portion of the reference trajectory based on an estimation of an unmeasured disturbance variable.