Force sensorless power assist control using operation force observer for nursing lift

Ishihara, Masakazu; Ito, Kazuaki; Inuzuka, Katsumi

doi:10.1109/icmech.2015.7083977

Cited by 4 publications

(2 citation statements)

References 5 publications

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“…Besides, the variable impedance control expressed by the Equation (6) does not require measuring the external force, although the stiffness update rule requires the use of joint torque sensor. As an alternative, the momentum observer [16] and external force observer [18] to estimate the external joint torques will be necessary.…”

Section: Discussionmentioning

confidence: 99%

Input-to-State Stability of Variable Impedance Control for Robotic Manipulator

Park

Choi

2020

Applied Sciences

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Variable impedance control has been required to perform a variety of interactive tasks in contact with environments. In some cases, the time-varying stiffness matrix of the impedance model can be used to achieve high performance for uneven contact tasks. In the paper, two sufficient conditions are proposed to ensure the input-to-state stability (ISS) irrespective of time-varying stiffness. Furthermore, the update rule of the stiffness is also suggested in such a way that the asymptotic stability is guaranteed under certain region conditions. Even when the update rule is not applied, the ISS is at least assured. In other words, the error is always bounded only if the external force/torque is bounded. In detail, two sufficient conditions offer the lower bound of stiffness and the upper bound of its time derivative. Simulation results show that the ISS of variable impedance control is achieved if the proposed sufficient conditions are satisfied. Also, we can confirm the asymptotic behavior in the simulation when the stiffness is updated according to the given rule.

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Section: Discussionmentioning

confidence: 99%

Input-to-State Stability of Variable Impedance Control for Robotic Manipulator

Park

Choi

2020

Applied Sciences

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“…Hence, no force sensor was required if force control for the system was designed based on (5). It was force sensor-less force control [31], but an acceleration sensor might be required for the force control as the acceleration was used to feedback. We called it the force control with acceleration feedback (recognized as the force control method-1 or simply force control 1 in this article).…”

Section: A Position Control Methodsmentioning

confidence: 99%

Weight-Prediction-Based Predictive Optimal Position and Force Controls of a Power Assist Robotic System for Object Manipulation

Rahman

Ikeura

2016

IEEE Trans. Ind. Electron.

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In the first step, a novel approach of inclusion of weight prediction in the dynamics of a power assist robotic system (PARS) for lifting objects is proposed. Then, a position control and two force control algorithms are derived using the weight-prediction-based dynamics so that the inclusion of weight prediction in the controls can mitigate the effects of the erroneous feedforward input force programming of the human. In the second step, a variable-inertia-based empirical predictive control strategy is proposed to augment the performance of the controls. The control algorithms are tested using a 1-DOF PARS for lifting light-weight objects. A novel scheme is proposed to evaluate and optimize the performance of the controls. The experimental results show that weight-prediction-based predictive controls help optimize human-robot interaction (HRI) and manipulation performance. The results show that the position control produces better HRI and performance than the force controls, and the force control designed with force feedback performs better than the force control designed with acceleration feedback. The results seem to be very useful to design predictive controls of power assist robots for handling heavy objects in industries.

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