Contents xv
4.7 Variable-Gain Super-Twisting Control ............................... 170
4.7.1 Problem Statement ........................................... 171
4.7.2 The Variable-Gain Super-Twisting Algorithm.............. 172
4.8 Case Study: The Mass–Spring–Damper System ..................... 176
4.8.1 Model Description ........................................... 176
4.8.2 Problem Statement ........................................... 177
4.8.3 Control Design ............................................... 178
4.8.4 Experimental Results ........................................ 179
4.9 Notes and References.................................................. 179
4.10 Exercises ............................................................... 182
5 Analysis of Sliding Mode Controllers in the Frequency Domain ....... 183
5.1 Introduction ............................................................ 183
5.2 Conventional SMC Algorithm: DF Analysis ......................... 184
5.3 Twisting Algorithm: DF Analysis .................................... 193
5.4 Super-Twisting Algorithm: DF Analysis ............................ 196
5.4.1 DF of Super-Twisting Algorithm............................ 196
5.4.2 Existence of the Periodic Solutions ........................ 198
5.4.3 Stability of Periodic Solution ............................... 200
5.5 Prescribed Convergence Control Law: DF Analysis ................ 201
5.6 Suboptimal Algorithm: DF Analysis ................................. 203
5.7 Comparisons of 2-Sliding Mode Control Algorithms ............... 205
5.8 Notes and References.................................................. 208
5.9 Exercises ............................................................... 208
6 Higher-Order Sliding Mode Controllers and Differentiators ........... 213
6.1 Introduction ............................................................ 214
6.2 Single-Input Single-Output Regulation Problem..................... 216
6.3 Homogeneity, Finite-Time Stability, and Accuracy .................. 217
6.4 Homogeneous Sliding Modes ......................................... 222
6.5 Accuracy of Homogeneous 2-Sliding Modes ........................ 223
6.6 Arbitrary-Order Sliding Mode Controllers ........................... 225
6.6.1 Nested Sliding Controllers .................................. 225
6.6.2 Quasi-continuous Sliding Controllers....................... 227
6.7 Arbitrary-Order Robust Exact Differentiation ....................... 228
6.8 Output-Feedback Control ............................................. 230
6.9 Tuning of the Controllers.............................................. 233
6.9.1 Control Magnitude Tuning .................................. 233
6.9.2 Parametric Tuning............................................ 233
6.10 Case Study: Car Steering Control..................................... 234
6.11 Case Study: Blood Glucose Regulation .............................. 237
6.11.1 Introduction to Diabetes ..................................... 237
6.11.2 Insulin–Glucose Regulation Dynamical Model ............ 240
6.11.3 Higher-Order Sliding Mode Controller Design............. 241
6.11.4 Simulation .................................................... 244