Impedance control stability properties in common implementations

Lawrence, Dale

doi:10.1109/robot.1988.12222

Cited by 247 publications

(171 citation statements)

References 8 publications

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“…They do not allow an arbitrary choice of the target impedance parameters. 28 Other solutions (such as force based impedance control 29 ), rely on control of the manipulator dynamics in its operational space. Actuator commanded forces f com are computed, such as…”

Section: End-effector Controlmentioning

confidence: 99%

Planning and controlling cooperating robots through distributed impedance

2002

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This article presents distributed impedance as a new approach for multiple robot system control. In this approach, each cooperating manipulator is controlled by an independent impedance controller. In addition, along selected degrees of freedom, force control is achieved through an external loop, to improve control of the object's internal loading. Extensive stability analysis is performed, based on a realistic model that includes robot impedance and object dynamics. Experiments are performed using two cooperating industrial robots holding an object through point contacts. Force and position control actions are suitably dispatched to achieve both internal loading control and object position control. Individual impedance parameters are specified according to the theoritical stability criterion. The performance of the system is demonstrated for transportation and contact tasks.

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Section: End-effector Controlmentioning

confidence: 99%

Planning and controlling cooperating robots through distributed impedance

2002

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“…In those attempts, the Jacobian has been used to obtain required torques to follow the desired trajectory. But the limitation of impedance control is that system becomes unstable if the mechanical impedance is high and it requires natural dynamics as well [127]. On the contrary, admittance controller, used in many haptic devices, position was being controlled while force taken as feedback [32,84].…”

Section: Control Issuesmentioning

confidence: 99%

A Brief Review on Robotic Exoskeletons for Upper Extremity Rehabilitation to Find the Gap between Research Porotype and Commercial Type

et al. 2017

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The number of disabled individuals due to stroke is increasing day by day and is projected to continue increasing at an alarming rate in United States. But the current amount of health professionals in physical therapy is inadequate to provide rehabilitation to these large groups. From early 1990s, researchers have been trying to develop an easy and feasible solution to this problem and lot of assistive devices both end effector type or exoskeleton type have been developed till to date. However, only a few of them have been commercialized and are being used in rehabilitation of post-stroke patients. Making the use of exoskeletons and other devices to regain lost motor function is rare. Providing therapy to this large group is quite impossible without commercializing of exoskeleton. This has motivated the authors to make a literature review and figure the reasons out that need to be solved to bridge the gap between research prototype to commercial version. This paper covers the necessity of incorporating robotic devices in rehabilitation, a brief description of existing devices particularly upper limb exoskeletons, their hardware limitations, and control issues. Our review shows that there are significant flaws in hardware design and developing control algorithm of exoskeletons to be available in rehabilitation program.

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“…All the above-mentioned force tracking control approaches exploit a manipulator with high stiffness dynamics and suffer from the inability to provide a soft compliant behavior. 18 However, this approach is not advisable for surgical targeting tasks, which require the repetitive execution of wide maneuvers from/to a home robotic configuration, e.g. during brain mapping procedures.…”

Section: Introductionmentioning

confidence: 99%

“…2 Thus, a torque-based impedance controller is more suited. 18 Impedance-controlled cooperative robots, e.g. the Acrobot system with back-drivable joints for robotic assisted orthopaedic surgery, 19 allow the natural transmission to the user of the interaction forces with the environment, both for human guidance and/or for tissue contact, without requiring direct force sensing.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Force Feedback Enhancement for Cooperative Robotic Neurosurgery Enforces Virtual Boundaries on Cortex Surface

Beretta

Ferrigno

Momi

2016

J. Med. Robot. Res.

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Surgeons can benefit from the cooperation with a robotic assistant during the repetitive execution of precise targeting tasks on soft tissues, such as brain cortex stimulation procedures in open-skull neurosurgery. Position-based force-to-motion control schemes may not be satisfactory solution to provide the manipulator with the high compliance desirable during guidance along wide trajectories. A new torque controller with non-linear force feedback enhancement (FFE) is presented to provide augmented haptic perception to the operator from instrument-tissue interaction. Simulation tests were performed to evaluate the system stability according to different non-linear force modulation functions (power, sigmoidal and arc tangent). The FFE controller with power modulation was experimentally validated with a pool of non-expert users using brain-mimicking gelatin phantoms (8%-16% concentration). Besides providing hand tremor rejection for a stable holding of the tool, the FFE controller was proven to allow for a safer tissue contact with respect to both robotic assistance without force feedback and freehand executions (50% and 75% reduction of the indentation depth, respectively). Future work will address the evaluation of the safety features of the FFE controller with expert surgeons on a realistic brain phantom, also accounting for unpredictable tissue motions as during seizures due to cortex stimulation.

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Impedance control stability properties in common implementations

Cited by 247 publications

References 8 publications

Planning and controlling cooperating robots through distributed impedance

Planning and controlling cooperating robots through distributed impedance

A Brief Review on Robotic Exoskeletons for Upper Extremity Rehabilitation to Find the Gap between Research Porotype and Commercial Type

Nonlinear Force Feedback Enhancement for Cooperative Robotic Neurosurgery Enforces Virtual Boundaries on Cortex Surface

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