Linear ADRC Blockset

A collection of different implementation forms of linear active disturbance rejection control (ADRC).

Overview

This blockset includes continuous- and discrete-time, output- and error-based, state-space and transfer function forms of linear active disturbance rejection control (ADRC):

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• The continuous-time state-space form of output-based ADRC is the "classic" linear form (cf. Gao, "Scaling and bandwidth-parameterization based controller tuning", DOI: 10.1109/ACC.2003.1242516).
• Discrete-time state-space forms are based on zero-order hold discretization using the current observer approach (cf. Miklosovic et.al., "Discrete implementation and generalization of the extended state observer", DOI: 10.1109/ACC.2006.1656547).
• Discrete-time transfer function forms exactly replicate the dynamics of the discrete-time state-space form (cf. Herbst/Madonski, "Tuning and implementation variants of discrete-time ADRC", DOI: 10.1007/s11768-023-00127-0).
• The inner loops of error-based forms (and hence stability properties) are identical to their output-based equivalents (cf. Madonski et.al., "ADRC in output and error form: connection, equivalence, performance", DOI: 10.1007/s11768-023-00129-y).

Features

• All blocks can be tuned using bandwidth parameterization (cf. Gao, "Scaling and bandwidth-parameterization based controller tuning", DOI: 10.1109/ACC.2003.1242516), either from time-domain or frequency-domain target values.
• Some blocks additionally allow using half-gain tuning (cf. Herbst et.al., "Half-gain tuning for active disturbance rejection control", DOI: 10.1016/j.ifacol.2020.12.1864), which reduces the impact of measurement noise on the controller output (may require the Control System Toolbox).
• Continuous-time variants feature controller output limitation with built-in windup protection, discrete-time variants additionally have a rate limitation option for the controller output.