Cartesian Impedance Control of Flexible Joint Robots: A Decoupling Approach

Ott, Christian; Albu‐Schäffer, Alin; Kugi, Andreas; Hirzinger, Gerd

doi:10.5772/4675

Cited by 9 publications

(11 citation statements)

References 18 publications

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“…It systemically renders mechanical properties of human muscles and tendons closer than rigidly controlled prostheses, allowing more natural and fluid movements and control. Furthermore, less vibrations occur in comparison to position controlled devices (Ott, 2008;Vorndamme et al, 2016). 4.…”

Section: User Benefitsmentioning

confidence: 99%

A transhumeral prosthesis with an artificial neuromuscular system: Sim2real-guided design, modeling, and control

Toedtheide,

Fortunić,

Kühn

et al. 2024

The International Journal of Robotics Research

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In this work we introduce a new type of human-inspired upper-limb prostheses. The Artificial Neuromuscular Prosthesis (ANP) imitates the human neuromuscular system in the sense of its compliance, backdrivability, natural motion, proprioceptive sensing, and kinesthetics. To realize this challenging goal, we introduce a novel human-inspired and simulation-based development paradigm to design the prosthesis mechatronics in correspondence to the human body. The ANP provides body awareness, contact awareness, and human-like contact response, realized via floating base rigid-body models, disturbance observers, and joint impedance control—concepts known from established state-of-the-art robotics. The ANP mechatronics is characterized by a four degrees of freedom (dof) torque-controlled human-like kinematics, a tendon-driven 2-dof wrist, and spatial orientation sensing at a weight of 1.7 kg (without hand and battery). The paper deals with the rigorous mathematical modeling, control, design and evaluation of this device type along initially defined requirements within a single prototype only. The proposed systemic and grasping capabilities are verified under laboratory conditions by an unimpaired user. Future work will increase the technology readiness level of the next generation device, where human studies with impaired users will be done.

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Section: User Benefitsmentioning

confidence: 99%

A transhumeral prosthesis with an artificial neuromuscular system: Sim2real-guided design, modeling, and control

Toedtheide,

Fortunić,

Kühn

et al. 2024

The International Journal of Robotics Research

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show abstract

“…Equation ( 8), that we name the rigid-joint robot model associated to the torque-controlled flexible-joint robot model (1)-( 4), has a mass matrix which includes the apparent motor inertia B θ , that in turn depends on the actual motor inertia B ρ and the low-level torque control gain K T . Equation ( 8) has already appeared in [26,Chapter 5] in the context of singular perturbation analysis of the torque-controlled flexible-joint robot dynamics (1)-( 4). However, no contact dynamics was included in [26,Chapter 5] and a formal proof of the derivation of the reduced order model ( 8) from singular perturbation theory with intermittent contacts and impacts is left for future investigation (a possible direction would be to explore the results presented in [27]).…”

Section: Equivalent Rigid-robot Model and Rigid Impact Mapmentioning

confidence: 99%

“…Equation ( 8) has already appeared in [26,Chapter 5] in the context of singular perturbation analysis of the torque-controlled flexible-joint robot dynamics (1)-( 4). However, no contact dynamics was included in [26,Chapter 5] and a formal proof of the derivation of the reduced order model ( 8) from singular perturbation theory with intermittent contacts and impacts is left for future investigation (a possible direction would be to explore the results presented in [27]). The observation that the mass matrix is corrected by the apparent motor inertia is important for the results discussed in Sections III and IV.…”

Section: Equivalent Rigid-robot Model and Rigid Impact Mapmentioning

confidence: 99%

Refined Post-Impact Velocity Prediction for Torque-Controlled Flexible-Joint Robots

Arias,

Weekers,

Morganti

et al. 2024

IEEE Robot. Autom. Lett.

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Predicting the post-impact velocity for torquecontrolled flexible-joint robots enhances impact-aware control schemes which exploit intentional collisions for achieving dynamic robotic manipulation and locomotion. Compared to a previous approach based on a fully rigid-robot assumption, this paper shows how an improvement in the post-impact velocity prediction can be obtained by taking into account the joints' motor inertias, transmission ratios, and low-level torque control gains, as well as the impact surface friction. The paper also proposes a more robust method to estimate the gross post-impact velocity profile from experimental data via a polynomial fit. The improvement of the new post-impact velocity prediction is illustrated by means of both numerical simulations as well as 50 experimental trials on a commercially available torque-controlled robot. The recorded impact data and prediction algorithms are shared openly for reproducibility and further research.

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“…In this work, we chose to use a rigid-body model in which the arm is divided into a chain of rigid links connected by revolute joints, which has been shown to be sufficiently accurate to capture the behavior of real soft robots in navigation and manipulation tasks (43,44). This choice allows us to apply Cartesian impedance theory (45) to describe the relationship between configuration-space compliance and task-space compliance and readily gain useful insights regarding how to design more capable soft robot arms.…”

Section: Modelingmentioning

confidence: 99%

Increasing the payload capacity of soft robot arms by localized stiffening

Bruder,

Graule,

Teeple

et al. 2023

Sci. Robot.

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Soft robot arms offer safety and adaptability due to their passive compliance, but this compliance typically limits their payload capacity and prevents them from performing many tasks. This paper presents a model-based design approach to effectively increase the payload capacity of soft robot arms. The proposed approach uses localized body stiffening to decrease the compliance at the end effector without sacrificing the robot’s range of motion. This approach is validated on both a simulated and a real soft robot arm, where experiments show that increasing the stiffness of localized regions of their bodies reduces the compliance at the end effector and increases the height to which the arm can lift a payload. By increasing the payload capacity of soft robot arms, this approach has the potential to improve their efficacy in a variety of tasks including object manipulation and exploration of cluttered environments.

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Cartesian Impedance Control of Flexible Joint Robots: A Decoupling Approach

Cited by 9 publications

References 18 publications

A transhumeral prosthesis with an artificial neuromuscular system: Sim2real-guided design, modeling, and control

A transhumeral prosthesis with an artificial neuromuscular system: Sim2real-guided design, modeling, and control

Refined Post-Impact Velocity Prediction for Torque-Controlled Flexible-Joint Robots

Increasing the payload capacity of soft robot arms by localized stiffening

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