## 3 Results
### Experimental Testing of the Prosthetic System for LLD Correction
#### 3.4.2 Experimental Testing of the Prosthetic System  
In the initial phase of the testing process, which entailed less complex measurements of EPM displacement, an alternative, more accessible equipment configuration based on direct contact was utilized. The capacity to compensate for LLD was the focus of this study, which employed a direct contact measurement technique to evaluate this capacity. The responses of the SATP and the automatic length adjustments of the extensible prosthetic module mounted on the test mannequin were monitored, as illustrated in Figure 10.  
Figure 10: Positioning of the devices used in the prosthesis behavior study: (**a**) schematic representation (1—digital dial gauge; 2—artificial limb; 3—temporary support blade; 4—classic dial gauge; 5—temporary support blade; 6—intact contralateral limb equipped with a mechanism for simulating LLD). (**b**) overview of the experimental setup, with the dial gauges in their operating positions. The measurements were conducted using a digital comparator (1)--Mitutoyo Corporation, Kawasaki, Japan--that was placed in direct contact with the movable component of the EPM (2), which was attached to the residual limb (3). This attachment was facilitated by a temporary support blade (3) that was designed to extend the contact surface and facilitate direct interaction between the comparator's probe and the displaceable element. The experimental setup was designed to enable controlled simulation of body imbalance in the mannequin through a mechanism that mimics lower limb length discrepancy. The discrepancy, induced by the simulated difference in limb length, was addressed by employing a crank integrated within the mannequin and meticulously monitored with a dial comparator (4) attached to the movable portion of the intact contralateral limb (6) via a temporary support blade (5). An Absolute Solar Digimatic Indicator, model ID-S1012 SB (Mitutoyo Corporation, Kawasaki, Japan), was utilized and connected to a PC interface. The experimental data acquisition was performed using the dedicated software, MeasureLink USB-ITPAK, version 2.000 (Mitutoyo, MiCAT--Mitutoyo Intelligent Computer Aided Technology, Kanagawa, Japan) [38]. The software facilitated a reliable connection with the data acquisition device, the digital comparator, whose technical specifications are presented in Table 4.  
In the course of the experiments, a series of LLD values were systematically simulated. This was made possible by utilizing the LLD simulation mechanism integrated into the right limb of the test mannequin. The simulated LLD values ranged from 1 to 10 mm, with 1 mm increments. A selection of the experimental data obtained is presented in Figure 11.  
The displacement data demonstrated a gradual approach to the target value (simulated LLD) through a series of incremental steps, with each step corresponding to an approximate displacement of 0.4-0.5 mm, as illustrated in Figure 12. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Technical Specifications** \\ \hline Resolution & 0.01 mm \\ \hline Nominal stroke & 12.7 mm \\ \hline Display & LCD \\ \hline Maximum response speed & Unlimited \\ \hline Power supply & Solar battery (can operate continuously above 40 lux \\ \hline Charging time & 1.5 h at 500 lux \\ \hline Functions & Zero-point setting (Origin) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Technical parameters of the Absolute Solar Digimatic Indicator [39]. Figure 11: The variation of SATP displacement during the compensation of a 1 mm LLD. In Figure 13, the red curve depicts the variation of simulated lower limb length discrepancy values within the 1-10 mm range. This figure is a centralized graphical representation. The duration of the compensation procedure was found to be approximately 45 s for a 1 mm discrepancy (see Figure 11) and 180 s for a 5 mm discrepancy (see Figure 12). These findings serve to highlight the dependence on the magnitude of the LLD.