Model Sequence Controller for Overshoot-Free Trajectory Generation
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Solution Overview
Problem
Classic controllers in control loops often face conflicts between disturbance correction and overshoot, and dead times in controlled systems negatively impact control performance, requiring complex parameter adjustments that are difficult to automate and require specialized knowledge.
Innovation Solution
A model sequence control system using a master and slave controller, where the master controller generates trajectories online and the slave controller corrects deviations, allowing independent adjustment of control and disturbance behavior, with automated parameter determination facilitated by historical data and model-based design methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If classical controllers (P, PD, PI, PID) are used to optimize disturbance response, then disturbance compensation improves, but reference response exhibits undesirable overshoot
Solution Approach 1:
The control device is segmented into two independent controllers: a feedforward controller for reference behavior and a follower controller for disturbance behavior. This segmentation allows each controller to be optimized for its specific function without compromising the other, resolving the contradiction between disturbance compensation and reference response overshoot.
Solution Approach 2:
The invention changes the control parameters by introducing a feedforward controller that pre-calculates optimal manipulated variable trajectories based on a simulation model. This allows the reference response to follow a predetermined optimal path, eliminating overshoot while the follower controller independently handles disturbance compensation.
2Manufacturing precision
If controller parameters are adjusted to eliminate overshoot in step response, then reference response improves, but disturbance response deteriorates significantly
Solution Approach 1:
By dividing the control device into feedforward and follower controllers, the invention enables independent optimization of reference and disturbance responses. The feedforward controller eliminates overshoot through pre-calculated trajectories, while the follower controller maintains robust disturbance compensation, preventing the deterioration seen in single-controller systems.
Solution Approach 2:
The feedforward controller performs preliminary action by pre-calculating the optimal manipulated variable trajectory before disturbances occur. This preliminary trajectory planning ensures overshoot-free reference response while the follower controller is ready to compensate for any deviations caused by disturbances.
3Stability of the object's composition
If conventional controllers are used in systems with dead times, then stable behavior is ensured, but control loop dynamics must be significantly slowed down
Solution Approach 1:
The feedforward controller performs preliminary calculation of the optimal trajectory, anticipating the system's response to setpoint changes. By pre-planning the manipulated variable profile based on the simulation model, the system can respond faster to dead times while maintaining stability, as the trajectory is optimized in advance rather than reacting slowly to maintain stability.
Solution Approach 2:
The follower controller provides feedback to correct deviations between the actual controlled variable and the reference trajectory. This feedback mechanism allows the system to maintain stability even with faster dynamics, as any deviations caused by dead times are quickly corrected by the follower controller.
4Use of energy by moving object
If trajectory control with pre-calculated trajectories is used, then computational intensity is reduced, but only pre-calculated trajectories are available during operation
Solution Approach 1:
The feedforward controller uses a simulation model (a copy of the controlled system's dynamics) to generate trajectories online. This copying approach allows the system to calculate optimal trajectories in real-time without excessive computational load, as the simulation model provides a simplified representation that can be processed efficiently while still adapting to current operating conditions.
Data Source
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AI summary
The invention relates to a system and a method for determining the parameters of a controller (8) for a controlled system (1). A simulation model (10, 12) for the controlled system (1) is identified on the basis of detected input and output signals (u; y) of the controlled system (1). Parameters of a master controller (11) and of a sequence controller (14) used in a pilot control process (9) for the controlled system (1) are automatically defined on the basis of model-based design methods for a controller designed as a model sequence controller (14). The behaviour of the closed-loop system can be improved further by means of a subsequent optimization method. Advantageously, the controller can be designed without any particular control engineering expertise, and thus the frequency of use for model sequence controllers, with their many advantages, can be significantly increased in practical applications.