Improved Trajectory Planning for FES-Induced STS Movement Restoration in Paraplegia

Abstract

The work presented an enhanced trajectory planning for better handling of Functional Electrical Stimulation (FES) actuated revival of sit-to-stand (STS) manoeuvre. Currently there the problem of lack of FES aided devices as results of the failures of the proposed equipment to pass clinical tests. Employing control systems techniques have been yielding fruitful results. Literature indicated that further enhancement of trajectory planning could help in achieving milestones towards better performances. Continuous and coupled with bump-free trajectories are some essential properties for better control systems designs for such systems. The proposed trajectory planning utilises the six-order polynomial. Comparisons are made with the five and seven order polynomials. The fifth order polynomials give an insight of the performance of the system with lower order polynomials while the seventh order gave that of the higher order counterparts. It was employed to enhance the desired movement trajectories. Obtained results portrayed that the trajectory planning achieved are continuous and the tendencies of the appearances of jerks or spikes are eliminated. Others are an improvement on execution time by 11%, reducing the upper and lower bound terminal velocities by 16.9% and 20.9% accordingly. Thus, these indicate the possibilities of realisations of higher performance control systems for the induced movement tasks.