N terms of amplitude. It indicates that the offset error of IMUs position is fixed and can not adjust with time.Table two. The RMSE comparison of three algorithms when IMUs on 3 subjects were bound in position 1.Subject 1 DWPSO HFE HAA HIE KFE KAA KIE AFE AAA AIE eight.65 three.72 4.53 five.77 1.12 three.16 four.03 5.76 21.05 GWO 9.09 six.42 five.13 six.86 three.42 5.26 5.69 6.83 23.07 GN 9.36 7.90 five.26 7.45 5.02 7.02 7.36 7.71 23.45 DWPSO ten.63 5.97 three.29 4.35 six.01 four.54 three.81 three.55 25.Topic 2 GWO 10.97 7.36 4.15 5.61 7.86 6.37 four.08 five.67 26.06 GN 11.05 12.53 four.69 5.99 10.34 7.63 6.62 9.71 26.83 DWPSO eight.17 three.42 5.71 2.06 4.98 1.57 5.43 three.26 20.Topic three GWO 9.65 7.83 6.08 3.41 6.93 four.25 8.62 four.54 21.79 GN 11.90 9.61 six.86 three.76 9.28 6.97 9.45 four.86 23.Table two shows the test benefits of the RMSE when IMUs on three subjects have been bound in position 1. In HFE , HIE , KFE and AIE , the performances in the 3 algorithms are close to each and every other. In HAA , KAA , KIE , AFE and AAA , the calibration performances from the DWPSO and GWO are better than GN. A probable explanation is that under this DOF, the variation of your joint isn’t substantial, which will affect the calculation of your Jacobian matrix as well as the accuracy of the calibration. The DWPSO and GWO don’t look at the Jacobian matrix, and their accuracy is Vc-seco-DUBA Autophagy significantly larger than GN. Additionally, the outcomes in Figure 12 show that when the joint angle is about 0 , the values from the DWPSO and GWO are closer to the Agistatin B medchemexpress reference value than GN, e.g., KAA or AFE . That is because the DOF isn’t the key activity of the joint, and can also have an effect on the efficiency with the GN algorithm. To extra intuitively evaluate the consistency between the outcomes on the 3 calibration algorithms plus the reference, we chosen the angle values of HAA and KIE in Figure 12 as samples and plot the Bland ltman diagram for analysis. As shown in Figure 13, the x-axes will be the average of every person amongst the reference worth and estimated value, the y-axes would be the difference of every individual between the reference plus the estimated. The two red lines in the figure will be the upper and decrease limits of your 95 consistency interval, the purple dotted line indicates that the average value in the difference is 0, along with the green line is definitely the typical worth from the difference amongst the reference value and also the estimated worth in each and every individual. The closer the green line is always to the purple dotted line, the higher the consistency involving the reference value plus the estimated worth. As shown in Figure 13a, in HAA , the average difference value of the DWPSO is the closest to 0, along with the consistency with the reference value will be the highest, the GWO would be the second, as well as the GN is definitely the lowest. As shown in Figure 13b, the consistency analysis of KIE can also be the highest inside the DWPSO. These final results are constant with the curve outcomes in Figure 12. On top of that, a lot of the benefits in Figure 13 are within the confidence interval, which explains why the waveforms with the estimated worth as well as the reference worth are related in Figure 12.Sensors 2021, 21,19 of60Hip Flexion/Extensionreference DWPSO GN GWO60Hip Abduction/Adductionreference DWPSO GN GWO(20 0 -20 0 1 2(20 0 -(a) HFE60(b) HAAKnee Flexion/Extensionreference DWPSO GN GWO reference DWPSO GN GWOHip Intra/Extra Rotation(20 0 -20 0 1 two(0 -50 5 0 1 two three(c) HIE20(d) KFEreference DWPSO GN GWOKnee Abduction/Adduction20 0 -20 -40Knee Intra/Extra Rotationreference DWPSO GN GWO(-10 -20 -30 0 1 two three 4((e) KAAAnkle Flexion/Ext.