Table 4. Comparison of the RMS deviation, objective, feedback gains, and co-contraction index (CCI) of the optimal solutions with and without co-contraction for the highlighted tasks.
The objective (required effort) is given for all tasks that achieved the required precision. The position and derivative gain, as well as the CCI, are only reported for the tasks which achieved the required precision with and without feedforward control.
| Maximum perturbation amplitude | 100 | 125 | 125 | 125 | |
|---|---|---|---|---|---|
| Required precision (deg) | 2.0 | 3.0 | 4.0 | 5.0 | |
| RMS deviation (deg) | No feedforward control | 2.7 | 3.6 | 4.0 | 5.0 |
| With feedforward control | 2.0 | 3.0 | 4.0 | 5.0 | |
| Objective | No feedforward control | – | – | 0.1005 | 0.0893 |
| With feedforward control | 0.0839 | 0.1244 | 0.1001 | 0.0892 | |
| Position gain | No feedforward control | – | – | 4.113 | 2.975 |
| With feedforward control | – | – | 3.864 | 2.920 | |
| Derivative gain | No feedforward control | – | – | 0.251 | 0.220 |
| With feedforward control | – | – | 0.232 | 0.219 | |
| CCI | No feedforward control | – | – | 0.77% | 0.98% |
| With feedforward control | – | – | 2.84% | 2.87% |