Improving teleoperation system performance in the presence of estimated external force

Fluoroscopy-guided placement of pedicle screws is usually used to position pedicle screws, although it is highly risky due to lack of accuracy during operation and surgeon's intensive labor requirement during surgery. In this study, a new method was introduced to consider the issues and we tried to reduce the risk of pedicle screw placement and drilling process. To put pedicle screws in the correct position and orientation, a specific drill guide is designed and fabricated by additive manufacturing technology. In addition, since the drilling process is remarkably important and it is usually dependent on surgeon skill, therefore a teleoperation system is proposed to perform this task. In order to let the surgeon to have better control on the patient, a control scheme including position and velocity signals along with surgeon force and reaction force of vertebra was proposed. This helped the surgeon for proper control on the patient during surgery. A force estimation algorithm was presented to eliminate measuring external force signal. Consequently, 10 vertebras were used to evaluate specific drill guide and teleoperation system simultaneously. Then, the computed tomography evaluation demonstrated that Kirschner wire trajectories followed the planned axes with an error between 1 and 2 mm in 20% of cases and less than 1 mm in 80% of cases. The results obtained by the teleoperation system showed that the surgeon, in the master side, has proper control over the patient body in the slave side because the slave robot followed the master position. Furthermore, the surgeon in the master side sensed the reaction force of vertebra in the slave side appropriately.

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“…

{\overset{false^}{f}}_{h}

and

{\overset{false^}{f}}_{e}

are the estimated surgeon and spine force. Note that the force estimation algorithm has been performed according to the literature .…”

Section: Methodsmentioning

confidence: 99%

A New Template and Teleoperation System for Human‐Guided Spine Surgery

et al. 2018

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“…Theorem 1. Consider the system (27) with the control laws (35) in the absence of the human and environmental torques ( ℎ ( ) = ( ) = 0). The position tracking errors defined in (16) can be driven onto the sliding mode surface and converge to zero in finite time under time-varying delays.…”

Section: Stability Analysismentioning

confidence: 99%

“…However, they regard the human and environmental impedances as constants with known coefficients or the systems are assumed to be linear with known dynamics, which are against reality. Several force control methods are also applied in the nonlinear teleoperation system by adding the square of force tracking errors [23]- [24] or using dynamic model-based force observer [25]- [27]. Only using force tracking errors with a constant gain as force controllers, these approaches have no superiority on fast convergence of human and environmental forces.…”

mentioning

confidence: 99%

Multilateral Teleoperation With New Cooperative Structure Based on Reconfigurable Robots and Type-2 Fuzzy Logic

Sun

Liao

et al. 2019

IEEE Trans. Cybern.

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This paper develops an innovative multilateral teleoperation system with two haptic devices on the master side and a newly designed reconfigurable multi-fingered robot on the slave side. A novel nonsingular fast terminal sliding-mode algorithm, together with varying dominance factors for cooperation, is proposed to offer this system's fast position and force tracking, as well as an integrated perception for the operator on the reconfigurable slave robot (manipulator). The Type-2 fuzzy model is used to describe the overall system dynamics, and accordingly a new fuzzy-model-based state observer is proposed to compensate for system uncertainties. A sliding-mode adaptive controller is designed to deal with the varying zero drift of the force sensors and force observers. The stability of the closed-loop system under time-varying delays is proved using Lyapunov-Krasovskii functions. Finally, experiments to grasp different objects are performed to verify the effectiveness of this multilateral teleoperation system.

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“…Van Damme et al [20] used the leastsquares method and a disturbance observer to estimate the robot end forces from noisy driver torques and discussed the intrinsic relationship between the least-squares method and the disturbance observer method. Azimifar et al [21] proposed an improved disturbance observer for the control of a constant time-delay nonlinear bilateral teleoperation system. e results of these researches show that a disturbance observer can replace the force/torque sensor measurement signals with AC servo motor signals to obtain basic force information, thus implementing the robot end constant force-tracking control.…”

Section: Introductionmentioning

confidence: 99%

“…References [10][11][12][13][14][15][16][17][18][19][20][21][22][23] mentioned the use of the disturbance observer to estimate external forces, but the research topics are different from the topics studied in this paper. References [10,11,15] were validated only on two-link robots with simple dynamics models.…”

Section: Introductionmentioning

confidence: 99%

Disturbance Observer‐Based Robot End Constant Contact Force‐Tracking Control

Liang

2019

Complexity

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A disturbance observer-based hybrid sliding mode impedance control method is proposed in this paper, which is able to achieve robot end constant contact force-tracking control without force/torque sensors. The method requires only the values of joint torque, joint angle, and joint angular velocity, which are converted by robot servo motor signals, to implement the control. The control scheme consists of two parts: one is a disturbance observer and the other is a hybrid sliding mode impedance controller. The disturbance observer, which takes robot internal signals mentioned above as the inputs to estimate the robot end contact force, is designed based on generalized momentum, thus improving the estimation accuracy. The hybrid sliding mode impedance controller, which uses the values estimated by the disturbance observer and the robot internal signals as the inputs to calculate the corresponding position adjustment, integrates both the impedance control and sliding mode control, thus improving the force-tracking performance and robustness. Experimental results show that the proposed disturbance observer-based hybrid sliding mode impedance control method possesses high control precision.

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Improving teleoperation system performance in the presence of estimated external force

Cited by 24 publications

References 23 publications

A New Template and Teleoperation System for Human‐Guided Spine Surgery

A New Template and Teleoperation System for Human‐Guided Spine Surgery

Multilateral Teleoperation With New Cooperative Structure Based on Reconfigurable Robots and Type-2 Fuzzy Logic

Disturbance Observer‐Based Robot End Constant Contact Force‐Tracking Control

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