*4.1. Test 1*

Test 1 consists of a bending movement towards a fixed inclination angle, in each of the four orientations: 0◦, 90◦, 180◦ and 270◦. This test shows how the joint starts in a resting position, performs the action and then returns to the resting position before it bends at the next orientation. The resting position is 0 degrees of inclination and orientation. Tests were performed for 30◦, 45◦ and 60◦ inclination and results are shown in Figure 18 for the encoder data and Figure 19 for the sensor data.

Test 1—Encoder data

(**a**) Inclination versus time through encoder measurements for 30◦ inclination.

(**b**) Orientation versus time through encoder measurements for 30◦ inclination.

(**c**) Inclination versus time through encoder measurements for 45◦ inclination.

(**d**) Orientation versus time through encoder measurements for 45◦ inclination.

(**e**) Inclination versus time through encoder measurements for 60◦ inclination.

(**f**) Orientation versus time through encoder measurements for 60◦ inclination.

**Figure 18.** Test 1—Encoder data. Fixed 30◦, 45◦ and 60◦ inclination for four orientations: 0◦, 90◦, 180◦ and 270◦. The blue line is the experimental data obtained from the encoder and the orange dotted line is the reference.

Test 1—Sensor data

(**a**) Inclination versus time through inertial sensor measurements for 30◦ inclination.

(**b**) Orientation versus time through inertial sensor measurements for 30◦ inclination.

(**c**) Inclination versus time through inertial sensor measurements for 45◦ inclination.

(**d**) Orientation versus time through inertial sensor measurements for 45◦ inclination.

(**e**) Inclination versus time through inertial sensor measurements for 60◦ inclination.

(**f**) Orientation versus time through inertial sensor measurements for 60◦ inclination.

**Figure 19.** Test 1—Sensor data. Fixed 30◦, 45◦ and 60◦ inclination for four orientations: 0◦, 90◦, 180◦ and 270◦. The blue line is the experimental data obtained from the encoder and the orange dotted line is the reference.
