## 3 Results
### Experimental Testing of the Prosthetic System for LLD Correction
#### 3.4.2 Experimental Testing of the Prosthetic System
The second curve, illustrated in blue, demonstrates the SATP's automated compensation for the simulated LLD values, utilizing the computer vision-based method. This facilitates a direct visual comparison between the manually induced LLD at the experimental stand and the adaptive prosthesis's ability to restore symmetry to the anatomically shaped mannequin by automatically compensating for the LLD. The relative error associated with the SATP's correction of this imbalance is 2.44%, corresponding to a mean absolute error of 0.134 mm based on the set of test cases. For the complex measurements requiring high precision and detailed analysis of the EPM movements, a high-performance system based on Digital Image Correlation (DIC)--the ARAMIS 3D DIC System, Teledyne Dalsa 12M (Carl Zeiss, Jena, Germany), managed by the PONTOS software, version 6.3.1-1 (PONTOS Software GmbH, Jena, Germany)--was utilized. Following calibration of the experimental setup using this system, the 3D coordinates of two reflective markers monitored by a set of high-performance cameras were obtained. The first marker was positioned on the movable assembly of the EPM, and the second on the prosthetic foot, as illustrated in Figure 14.  
Figure 12: The variation of SATP displacement during the compensation of a 5 mm LLD. Figure 13: SATP’s ability to compensate for different LLD values via computer vision. Subsequent to receiving the command from the control unit (CU), the EPM underwent a modification in length, thereby inducing a change in the prosthetic lower limb's initial state. The displacement was monitored by calculating the initial 3D coordinates and comparing them with the final 3D coordinates after the EPM movement had been completed. In Figure 15, the graph illustrates the variation in displacement and velocity along the Y-axis for point 1 (P1) during one prosthesis cycle. Initially, the prosthesis is in the reference position, without any displacement (Stage 0). Subsequent activation of the compensation mechanism, executed in a meticulous manner, instigates an incremental rise in displacement, culminating at a maximum value of approximately 15 mm. This marks the prosthesis's attainment of the predetermined stroke limit. Subsequently, the displacement undergoes a gradual decrease, and the prosthesis reverts to its initial position, thereby completing a full movement cycle. The displacement velocity, illustrated by the blue curve in Figure 15, maintains a proximity to zero for the majority of the movement, thereby indicating a controlled dynamic. At the initiation of the stroke, the velocity undergoes a gradual increase, reaching  
Figure 14: View during EPM testing in the PONTOS software v. 6.3.1-1 (the upper marker: P1). Figure 15: Variation of displacement and velocity along the Y-axis for P1 during a programmed stroke with return to the initial position. a maximum that corresponds to the acceleration phase. As the prosthesis approaches its maximum displacement, a gradual decrease in speed is observed. During the return phase, the speed displays symmetrical behavior, thereby confirming that the prosthesis movement is balanced and stable. As illustrated in Figure 16, the displacement of P1 was measured during the tests on the three axes: X, Y, and Z. The curve for the Y-axis illustrates the movements performed by the EPM for adapting the prosthesis length (advancing and retracting/increasing and decreasing the length for the programmed stroke). The X-axis indicates a minor misalignment of the movable component relative to the fixed component of the EPM, while the Z-axis highlights any play in the mechanism caused by the shock of coupling the actuator to the rotation, particularly in the area of the elastic bushing that facilitates the connection with the EPM axis. As illustrated in Figure 17, the displacement-acceleration on the Y-axis of P1 from the EPM during the prosthesis's advance cycle (extension) and retraction cycle (shortening) is demonstrated.