This paper proposes a force control system using the State Observer Based Disturbance Observer (SO-DOB) and the State Observer Based Reaction Force Observer (SO-RFOB) based on the novel observer gain tuning methodology. The observer gain tuning methodology is based on the stable margin theory. By using the proposed gain tuning methodology, the system stability and the robustness of the SO-DOB and the SO-RFOB is guaranteed. The validity of the proposed method was tested by both simulation and the experiment works. From the results, the control performance was improved compared with the DOB and the RFOB based on the Low Pass Filter (LPF) based estimation.
The aim of this study was to establish the effectiveness of a resistance training programme, designed to improve vertical jumping ability, on the grab, swing and rear-weighted track starts in swimming. Twenty-three female non-competitive swimmers participated (age 19.9±2.4 years; mean±s). The diving techniques were practised weekly for 8 weeks. The participants were randomly assigned to a control group (n = 11) or a resistance-training group (n = 12), which trained three times a week for 9 weeks. The tests before and after the training programme involved performing each dive technique and six dry-land tests: two countermovement jumps (with and without arms), two isokinetic squats (bar speeds of 0.44 and 0.70 rad.s-1) and two overhead throws (with and without back extension). A repeated-measures multivariate analysis of variance was used to show that resistance training improved performance in the dry-land tests (P < 0.0001). No significant improvements due to training were found for any temporal, kinematic or kinetic variables within the grab or swing starts. Significant improvements (P < 0.05) were found for the track start for take-off velocity, take-off angle and horizontal impulse. The results suggest that the improved skill of vertical jumping was not transferred directly to the start, particularly in the grab technique. Non-significant trends towards improvement were observed within all starts for vertical force components, suggesting the need to practise the dives to retrain the changed neuromuscular properties.