Abstract

Postural stability and balance regulation is an intricate neurophysiological task which entails coordination of movements for successful execution. This task is proficiently regulated by central nervous system. The sensory feedback through muscles via proprioceptors has neural transmission delays which make the movement coordination and computations by central nervous system a complex problem to deal with. This paper addresses a nonlinear robust technique based on feedback linearization for postural stabilization of a single-link biomechanical model in the presence of physiological latencies. We included neural transmission delays in sensory feedback from proprioceptors. We developed [Formula: see text] optimal controller and integrated it with feedback linearization to calculate the joint torque for the biomechanical task. This modeling scheme is simulated in MATLAB/SimMechanics, and the simulation results for the nonlinear biomechanical model are developed. The joint torque compensates for the delays and settles the motion profiles within anatomical constraints. The position profile shows a bit higher overshoot (0.02, 0.03 rad) in case of delays; however, the settling time is same for the profiles with and without delay. The extensor torque is same for all profiles; however, the flexion torque increases for the delayed case. The simulation results show the applicability of this scheme for further analysis of the biomechanical task.

Highlights

  • Maintenance of balance in an upright posture is basic and perhaps the most essential requirement in daily life.[1]

  • This study investigates the robust nonlinear compensator design for the postural control of a single-link biomechanical model in the presence of proprioceptive feedback delays and noisy sensor data from joints

  • The H2 compensator calculates the linear gains for the nonlinear controller and observer

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Summary

Introduction

Maintenance of balance in an upright posture is basic and perhaps the most essential requirement in daily life.[1]. Roy and Iqbal[24,25] studied the postural stabilization problem with delays in position and velocity feedback In their research, they stabilized the inverted pendulum–based single-link biomechanical model with proportional–integral–derivative (PID) controller as CNS function. This paper presents a nonlinear robust compensator design which represents the CNS function to regulate and control the movement coordination during maintenance of postural stability in the presence of neural transmission delays and noisy joint sensors. The feedback linearization technique in augmentation with H2 is used to construct control for postural maintenance of nonlinear biomechanical model and compensate for neural delays in the presence of noisy joint sensors. It is clear from the above equation that the system is input–output linearizable and the state feedback control law can be defined as u

LeLfmðxÞ
Discussion and conclusion

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