Adaptation of Gait Energetics to Ankle Exoskeleton Assistance Within and Across Visits: A Clinical Case Series

Application of Wearable Sensors in Actuation and Control of Powered Ankle Exoskeletons: A Comprehensive Review

“…Electric actuators were the most popular actuators deployed in the reviewed PAEs. They were powered by on-board battery packs [37,41,56,57,61,[65][66][67][76][77][78][79][80][81][82][83][84]86,87,94,[100][101][102]112,113,115,[118][119][120]126,127,130,144,145,[156][157][158][159][160][172][173][174][175]177,184,187,189,234,235], DC off-board power supply units [10,…”

“…Phase-based control algorithms aim to track a desired ankle joint torque or angular movement based on the user’s gait phase and kinematic states, measured by a variety of mechanically intrinsic wearable sensors [ 10 , 37 , 38 , 39 , 40 , 41 , 43 , 49 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 ,…”

“…Electric actuators were the most popular actuators deployed in the reviewed PAEs. They were powered by on-board battery packs [ 37 , 41 , 56 , 57 , 61 , 65 , 66 , 67 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 86 , 87 , 94 , 100 , 101 , 102 , 112 , 113 , 115 , 118 , 119 , 120 , 126 , 127 , 130 , 144 , 145 , 156 , 157 , 158 , 159 , 160 , 172 , 173 , 174 , 175 , 177 , 184 , 187 , 189 , 234 , 235 ], DC off-board power supply units [ 10 , 39 , 109 , 116 ...…”

“…Although a number of reviewed articles utilized open-loop feed-forward algorithms for controlling actuation units [ 94 , 158 , 184 ], the majority of the considered studies developed a form of feedback controller ( Table 6 ). Classical proportional–integral–derivative (PID) feedback controllers [ 39 , 53 , 54 , 55 , 56 , 67 , 68 , 76 , 77 , 78 , 79 , 82 , 86 , 101 , 102 , 108 , 109 , 110 , 114 , 119 , 120 , 121 , 136 , 138 , 139 , 140 , 154 , 155 ] were the most frequently used control algorithms in the reviewed PAEs due to the simplicity of real-time implementation [ 239 ]. Integral, proportional, and derivative feedback is based on the past (I), present (P) and future (D) state of the system Three types of controllers have been devised based on the integral, proportional, and derivative feedback controllers that are widely used in PAEs: P [ 100 , 106 , 107 , 113 , 146 , 172 , 178 , 185 , 186 , 187 , 204 ], PI [ 85 , …”

“…Feedback controllers, regardless of their algorithm, are required to continuously monitor the actuator’s output and apply corrective strategies to ensure that the desired assistance will be transferred to the device, and later delivered to the user. Torque sensors [ 37 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 104 , 105 , 106 ], strain gauges [ 68 , 69 , 73 , 202 ], potentiometers, and load cells have been used to measure the actuator-generated torque, while tension sensors [ 53 , 182 ], force sensors [ 57 ], load cells [ 39 , 58 , 69 , 108 , 109 , 110 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 180 , 183 , 204 ], and strain gauges [ 72 , 113 , 181 ] have been used for measuring the tension force in the force transmission parts of the exoskeletons, such as the cables and ropes. Current sensors [ 39 , 85 , 161 , 162 ] and encoders [ 39 , 103 , ...…”