Junyoung Kim. (2021). Impedance Control of Human Ankle Joint via Electrically Evoked Antagonistic Muscle Co-contraction. doi: 10.22677/thesis.200000364984
Ⅰ. Introduction I.1. Functional electrical stimulation (FES) for paralyzed patients 1 I.2. Human joint impedance control with functional electrical stimulation 1 I.3. Joint control with antagonistic muscle co-contraction 2 I.4. Clinical-friendly functional electrical stimulation controller 3 I.5. Objectives of the thesis 3 II. Design of an impedance controller II.1. Robust impedance control with time delay estimation (TDE) for human ankle joint 5 II.2. Antagonistic muscle co-contraction allocator (AMCA) 7 II.3. Implementation of controller 11 II.4. The validity of the stiffness-based time delay estimation 13 II.5. Alteration of the desired intrinsic stiffness 15 III. Experimental Evaluation III.1. Environmental setup 17 III.2. Protocol 18 III.3. Control results: Step response 23 III.4. Control results: Disturbance response 27 IV. Effect of damping control: Compared with stiffness control IV.1. The necessity of the damping during impedance control 31 IV.2. Experiment with various damping 32 V. Toward optimal co-contraction during impedance control V.1. The trade-off between long-term usage and higher intrinsic stiffness level for better functional restoration 35 V.2. Experiment with changing the intrinsic stiffness level during control 35 VI. Effect of intrinsic stiffness on control performance VI.1. Verification of the pure effect of the intrinsic stiffness modulation 37 VI.2. Experiment with common static control gain 37 VII. Discussions and conclusions VII.1. Summary 39 VII.2. Effect of the antagonistic muscle co-contraction 39 VII.3. Limitations and suggestions for future works 40 Appendix A1. Stability analysis of the impedance controller 42 A2. Effect of the open-loop pulsewidth calculation model 44 A3. Design of inverted pendulum apparatus 48 A4. Pre-experiment sessions 51 References 54
