Constraint Enforcement

Find control actions that satisfy specified bounds and other constraints
Since R2021a

Some control applications require the controller to select control actions such that the plant states do not violate certain critical constraints. In many cases, the constraints are on plant states that the controller does not control directly. Instead, you define a constraint function that defines the constraint in terms of the control action signal.

Simulink^® Control Design™ software provides the following constraint enforcement methods for such applications.

Specify constraints as a function of plant states.
Specify constraints using control barrier functions.
Specify passivity constraints.

This functionality requires Optimization Toolbox™ software to compute the modified control actions that are closest to specified control actions, subject to constraints and action bounds.

Blocks

Constraint Enforcement	Modify control actions to satisfy constraints and action bounds
Barrier Certificate Enforcement	Modify control actions to satisfy barrier certificate constraints and action bounds (Since R2022a)
Passivity Enforcement	Modify control actions to satisfy passivity constraints and action bounds (Since R2023a)

Topics

Constraint Enforcement Basics

Constraint Enforcement for Control Design
You can modify control actions in real-time to satisfy constraints and action bounds.
Enforce Constraints for PID Controllers
Apply a known constraint function to a PID control application using the Constraint Enforcement block.
Learn and Apply Constraints for PID Controllers
Learn and apply an unknown constraint function for a PID control application using the Constraint Enforcement block.

Barrier Certificate Enforcement

Barrier Certificate Enforcement for Control Design
Modify control actions to satisfy barrier certificate constraints and action bounds.
Enforce Barrier Certificate Constraints for PID Controllers
Apply barrier certificate constraints to a PID control application using the Barrier Certificate Enforcement block.
Enforce Barrier Certificate Constraints for Adaptive Cruise Control
Enforce barrier certificate constraints for adaptive cruise control to maintain velocity and following distance.
Enforce Barrier Certificate Constraints for Collision-Free Robots
Enforce barrier certificate constraints for two robots to reach their target positions in collision-free manner.
Enforce Barrier Certificate Constraints for Collision-Free Multi-Robot System
Enforce barrier certificate constraints for three robots to reach their target positions in collision-free manner.

Passivity Enforcement

Passivity Enforcement for Control Design
Modify control actions to satisfy passivity constraints and action bounds.
Enforce Passivity Constraints for Quadruple-Tank System
Enforce passivity constraints for water height control in a quadruple tank system.
Enforce Passivity Constraint for Flexible Beam
Enforce passivity constraints for vibration control in a flexible beam.

Reinforcement Learning Applications

Train Reinforcement Learning Agent with Constraint Enforcement
Train a reinforcement learning agent with actions constrained using the Constraint Enforcement block.
Train RL Agent for Adaptive Cruise Control with Constraint Enforcement
Train a reinforcement learning agent for adaptive cruise control with enforced constraints on velocity and following distance.
Train RL Agent for Lane Keeping Assist with Constraint Enforcement
Train a reinforcement agent for lane keep assist with enforced constraints on lateral deviation.

Related Information

Constraint Enforcement for Improved Safety