Patient-Robot-Therapist Collaboration Using Resistive Impedance Controlled Tele-Robotic Systems Subjected to Time Delays

Abstract

In this paper, an approach to physical collaboration between a patient and a therapist is proposed using a bilateral impedance control strategy developed for delayed tele-robotic systems. The patient performs a tele-rehabilitation task in a resistive virtual environment with the help of online assistive forces from the therapist being provided through teleoperation. Using this strategy, the patient's involuntary hand tremors can be filtered out and the effort of severely impaired patients can be amplified in order to facilitate their early engagement in physical tasks. The response of the first desired impedance model is Downloaded From: http://mechanismsrobotics.asmedigitalcollection.asme.org/ on 08/08/2018 Terms of Use: http://www.asme.org/about-asme/terms-of-use Journal of Mechanisms and Robotics JMR-17-1209, Salarieh 2tracked by the master robot (interacting with the patient), and the master trajectory plus a deviation as the response of the second impedance model is tracked by the slave robot (interacting with the therapist).Note that the first impedance model is a virtual mass-damper-spring system that has a response trajectory to the combination of patient and therapist forces. Similarly, the second impedance model is a virtual mass-damper-spring system that generates the desired slave-master deviation trajectory as its response to the therapist force. Transmitted signals through the communication channels are subjected to time delays, which exist in home-based rehabilitation (i.e., tele-rehabilitation). Tracking of the impedance models responses in the presence of modeling uncertainties is achieved by employing a nonlinear bilateral adaptive controller and proven using a Lyapunov analysis. The stability of delayed teleoperation system is also proven using the absolute stability criterion. The proposed control method is experimentally evaluated for patient-therapist collaboration in resistive/assistive tasks. In these experiments, a healthy human operator simulates a post-stroke patient behavior during the interaction with the master robot.

Bifurcations in basic models of delayed force control

“…The digital effects related to sampling and zero-order hold in time were considered in several studies on force control [4][5][6][7], but it is less investigated in case of analogous time delays that are essential elements of models in human motion control [8], human force control [9,10] or human balancing [11][12][13][14]. Remote force control tasks of telemanipulation [15][16][17] and physical contacts between robots and humans via force control are actual research topics of haptic systems [18][19][20][21], specifically in rehabilitation robotics [22][23][24].…”

Robust Adaptive Observer-Based Predictive Control for a Non-Linear Delayed Bilateral Teleoperation System

“…where 𝜌, ∅ and ∅ are positive constant matrices and are properties of the human and the environment, respectively. Theorem 1: In the teleoperation system described by equation ( 1) with the control laws (24) and the IEAOB ( 13), (21) and the ASP (7), when the human and environmental forces satisfy (26), the velocities 𝑞 𝑡 , 𝑞 𝑡 and position errors are bounded, provided that 1) 𝐾 , 𝐾 , and 𝐾 are bounded and positive definite matrices, 2) 𝑇 , 𝑇 are bounded and continuous, Proof:…”

“…In addition, various nonlinearities and uncertainties, essentially existing in robot manipulators, have to be considered as more complex teleoperation tasks are increasing in recent years. Lots of control strategies have been proposed in the engineering community to cope with these problems, such as adaptive control [14][15][16][17][18][19][20][21], robust control [22][23][24][25], and neural network and fuzzy logic technique [11,[23][24][25][26][27][28][29][30][31], etc.…”

Motion Analysis and Tactile-Based Impedance Control of the Chest Holder of a Piggyback Patient Transfer Robot

“…e force acting on the care-receiver is also the most significant factor affecting the comfort of the care-receiver. An active impedance control [21][22][23][24][25][26][27][28][29] method was proposed to ensure the care-receiver's comfort. e control method could adjust the angle of the chest holder according to the deviation between the actual force acting on the care-receiver's chest P ext (t) and the force, making the care-receiver comfortable P ref .…”