Fig 1.
This scheme shows the general structure of the project and the interactions between the different tasks. See the text for details.
Fig 2.
Sensor configuration and protocol environment.
(a) the prosthetic system composed of the foot fixed under the orthotic boot. (b) The prosthetic system as worn by the participants during stair climbing.
Fig 3.
Segmentation of the stance phase and angle definitions.
(a) Segmentation of the stance phase based on the normalized vertical ground reaction force. (b) Diagram of the pitch angle (αpitch) defined as the angle between the longitudinal axis of the rearfoot segment and the ground surface. (c) Diagram of the flexion angle (αflexion) defined as the angle between the vertical axis of the rear foot segment and the forefoot segment.
Fig 4.
(a) Representation of the prototype foot composed of (i) a cosmetic shell, (ii) a filling foam, (iii) an ankle, and (iv) a blade. (b) PP Technology’s bolting system to connect the foot to the rest of the prosthetic leg composed of (v) an M10 bolt and (vi) a specific washer, (vii) ankle, and blade fixation with M5 bolts and inserts.
Fig 5.
Compression test setup.
Fig 6.
Normalized vertical GRF as a function of αpitch during within stance phase for five feet.
Each solid thick line corresponds to the mean values over all subjects, while the standard deviations are shown with shaded areas. The steps from 13 subjects were used to calculate PSACH, PK3_C, PK3_E, and PK4 statistics, while 5 subjects were used for PPRO (i.e., 5 among the 13 participants have tested PPRO).
Table 1.
Biomechanical specifications of four commercial feet and PPRO&.
Fig 7.
The final aspect of the foot prototype.
(a) A prototype foot over-injected with a cosmetic shell. (b) Assembly of the keel, blade, and foam before the final over-injection.
Table 2.
Choice of materials and process satisfying the cost requirements&.
Table 3.
Fatigue tests of the ankle and blade materials.
Fig 8.
Evaluation of the load-deflection response.
(a) Representation of the PPRO rigidity at different angles. (b) Simplified loading representation of the NvGRF. (c) Representation of the vertical deformation of different feet during a stance phase. Please note that Pk3 denotes the PK3_C foot here.
Fig 9.
Evaluation of the load-deflection response.
(a) Moment My of different during forefoot stance phase (from 0 to -30deg). (b) Representation of the position of the center of pressure on the X-axis.
Table 4.
Results from the daily-locomotion analysis and the prosthesis evaluation questionnaire&.