Electrical Stimulation for trunk control in paraplegia: A feasibility study

Paraplegic subjects lack trunk stability due to the loss of voluntary muscle control. This leads to a restriction of the volume of bi-manual workspace available, and hence has a detrimental impact on activities of daily living. Electrical Stimulation of paralysed muscles can be used to stabilize the trunk, but has never been applied in closed loop for this purpose. This paper describes the development of two closed loop controllers (PID and LQR), and their experimental evaluation on a human subject. Advantages and disadvantages of the two are discussed, considering a potential use of this technology during daily activities.

► Closed loop control of FES is a viable option to improve trunk posture in paraplegia.
► A PID controller for trunk stabilization via FES can be developed by trial and error.
► Requirements expressed in “control theory terms” do not relate to user benefits.
► Controller synthesis for this application does not require complex models.