Fig. 1. Schematic diagram of suspended gravity unloading system platform with beam-cable structure

Fig. 2. Single sling suspension gravity unloading system

Fig. 3. Nonlinear model fit force error

Fig. 4. One-step predictive block-structured nonlinear neural network model

Fig. 5. Cascaded multi-step prediction model

Fig. 6. Control diagram of single-tether gravity unloading system

Fig. 7. PAM nonlinear model predictive force tracking control

Fig. 8. Experimental platform for PAM data sampling

Fig. 9. Force error plot predicted by nonlinear neural network model

Fig. 10. Expected and actual force plot for introducing Gaussian noise

Fig. 11. Force error plot for introducing Gaussian noise

Fig. 12. Expected and actual force plot for tracking impact disturbance

Fig. 13. Force error plot for tracking impact disturbance

Fig. 14. Expected and actual force plot for tracking sinusoidal signal

Fig. 15. Force error plot for tracking sinusoidal signal

Fig. 16. Expected and actual force plot for tracking perturbed sinusoidal signal

Fig. 17. Force error plot for tracking perturbed sinusoidal signal

Fig. 18. Experimental platform for PAM force tracking control

Fig. 19. PAM expected and actual force in tracking experiment

Fig. 20. PAM expected and actual force plot for tracking step signal