0.12 0.10 0.08 0.06 0.04 0.02 0.00 S1 S3 S5 S7 S9 S11 S13 S15 S17 S19 S21 S23 S25 S27 S29 S31 S33 S35 S37 S39S-Avg 1.00 0.90 0.80 0.70 0.60 0.50 S1 S3 S5 S7 S9 S11 S13 S15 S17 S19 S21 S23 S25 S27 S29 S31 S33 S35 S37 S39S-Avg MMCNN SVR KNN GBRT (a) Force Estimation With the MMCNN Model 0.5 1 -1 1 0.5 1 0.5 1 0.5 1 0.5 1 -0.5 1,000 2,000 Original Force 3,000 4,000 Estimated Force (b) Figure 7. Experiment results of the hand force estimation based on either the MMCNN or MCNN. (a) The NMSE and R2 of the sEMGbased force-estimation results of different models tested on NinaPro DB2. (b) The estimated force profiles of six degrees of freedom (6 DoF) of one subject of NinaPro DB2 by the MMCNN. (Continued) DECEMBER 2022 * IEEE ROBOTICS & AUTOMATION MAGAZINE * 19 5,000 Error