*3.1. Simulation Results*

In this subsection, we use different values from Table 1 to estimate the work-space and range of motion. First, we show the variation of mean value results, and second the platform position simulation by changing the range of movement and angles.

#### Changing Statistical Mean Values

Figure 24a shows the complete manifold, taking into account the intervals *θ*1, *θ*<sup>2</sup> ∈ [−180 ◦ , 180 ◦ ). It also shows the platform's initial position, the TC axis reference, the initial ST reference, the initial orientation, and a parametric trajectory with equal angle rate variation. In Figure 24b is the attaching point A simulation; Figure 24c,d depicts the simulations of B and C, respectively.

**Figure 24.** Simulation of all points: (**a**) platform's central point, (**b**) attachment a, (**c**) attachment b, and (**d**) attachment c.

In Figure 25a we show the platform' central point simulation with variations of 10% below the statistical mean values; Figure 25b shows the simulation changing 10% over the statistical mean values; Figure 26a is the attaching point A simulation adding the 10% mean values; and Figure 26b subtracts 10% of the mean values. Figure 27a,b are the results for the platform attaching point B. We show the results for the attaching point C in Figure 28a,b.

**Figure 25.** Simulation of the platform central point with variations in the mean statistical values: (**a**) 10% below, and (**b**) 10% over.

**Figure 26.** Simulation of the platform's attaching point A: (**a**) mean values plus 10%, (**b**) mean values minus 10%.

**Figure 27.** Attaching point B simulation: (**a**) adding 10% to the statistic mean values, (**b**) subtracting 10%.

**Figure 28.** Simulation results for C: (**a**) mean values plus 10%, (**b**) mean values minus 10%.

Finally, by changing the range of maximum and minimum angles, an example of the interactive simulation is in Figure 29a,b. We capture the view of the sliders and also show the simulation rendering result.

**Figure 29.** Interactive simulation example: (**a**) sliders, (**b**) rendering.

#### *3.2. Final Prototype*

In this section, we describe the results of the TM design, which are the assembled device and calibration. We try several designs and finally the CAD model is in [44]. First, we show images of the connected electronics parts. Second, we assemble the structure and perform calibrations. Third, we probe the device in a healthy patient to validate the prototype adaptability. We print the structural parts using ABS and the draw-wire sensor using PLA; PETG is in the supports and the case.

#### 3.2.1. Printed and Connected Electronics

We place the electronics in each side. In Figure 30, the connections and box sides and charge of the batteries.

**Figure 30.** Connections and electronics.

#### 3.2.2. Printed and Assembled Structure

We assemble all structural components carefully, putting them together with stainlesssteel threaded rods; then we place the draw-wire sensors, the acquisition board, connections, and final structure for calibration. Figure 31 shows the assembly.

**Figure 31.** Assembled structure.

#### 3.2.3. Calibration Results

We calibrate the system by using a personal computer. The resulting calibration, and measures of the lengths, are in Figure 32. The lecture is at the initial position, then we compare with the SolidWorks ® model measurements and the Vernier caliper real measurements for each DWS. The Table 2 shows the calibration results.


**Figure 32.** Processing calibration interface.

**Table 2.** Calibration results with digital measurements and real measurements.


Figure 33a shows the length with a SolidWorks ® Measurement tool for module A, sensor 1; the lecture for sensor 2 is in Figure 33b. In Figure 33c, is the sensor 3 length. Table 3 shows the error measured in the real prototype and in SolidWorks ® .

**Figure 33.** Measuring in SolidWorks (2017–2018 Student Edition, Dassault Systèmes, Vélizy-Villacoublay, France) ®: (**a**) sensor 1, (**b**) sensor 2, (**c**) sensor 3.


**Table 3.** Error compared with SolidWorks ® measurements.
