Motion control of musculoskeletal systems with redundancy |
| |
Authors: | Hyunjoo Park Dominique M Durand |
| |
Institution: | (1) Neural Engineering Center, Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Wickenden 112, Cleveland, OH 44106, USA |
| |
Abstract: | Motion control of musculoskeletal systems for functional electrical stimulation (FES) is a challenging problem due to the
inherent complexity of the systems. These include being highly nonlinear, strongly coupled, time-varying, time-delayed, and
redundant. The redundancy in particular makes it difficult to find an inverse model of the system for control purposes. We
have developed a control system for multiple input multiple output (MIMO) redundant musculoskeletal systems with little prior
information. The proposed method separates the steady-state properties from the dynamic properties. The dynamic control uses
a steady-state inverse model and is implemented with both a PID controller for disturbance rejection and an artificial neural
network (ANN) feedforward controller for fast trajectory tracking. A mechanism to control the sum of the muscle excitation
levels is also included. To test the performance of the proposed control system, a two degree of freedom ankle–subtalar joint
model with eight muscles was used. The simulation results show that separation of steady-state and dynamic control allow small
output tracking errors for different reference trajectories such as pseudo-step, sinusoidal and filtered random signals. The
proposed control method also demonstrated robustness against system parameter and controller parameter variations. A possible
application of this control algorithm is FES control using multiple contact cuff electrodes where mathematical modeling is
not feasible and the redundancy makes the control of dynamic movement difficult. |
| |
Keywords: | Functional electrical stimulation Motion control Ankle joint Redundant system Neural network control Inverse steady-state control |
本文献已被 PubMed SpringerLink 等数据库收录! |
|