Design and Characterization of an Open-Source Robotic Leg Prosthesis

Azocar, Alejandro F.; Mooney, Luke M.; Hargrove, Levi J.; Rouse, Elliott J.

doi:10.1109/biorob.2018.8488057

Cited by 69 publications

(42 citation statements)

References 33 publications

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“…The same motor connected in series with an elastic element requires about 25 J per stride, i.e., a 50% reduction in the energy dissipated [9]. Thus, SEAs represent a viable actuator alternative for the design of powered prosthetic legs, with some examples reported in [12], [19], [20].…”

Section: Our Contributionmentioning

confidence: 99%

“…Robust design is important in this application as human locomotion and manufacturing methods are inherently uncertain. For instance, the ankle joint position during human locomotion varies with a standard deviation of ±5 • [29], and the stiffness of a manufactured spring has a standard deviation of about ±10% from the desired stiffness value [20].…”

Section: Case Study: Simulation Of a Powered Prosthetic Anklementioning

confidence: 99%

“…In our formulation, we take advantage of the connection between uncertainty in the kinematics and kinetics of the load and our definition of uncertainty sets to obtain a robust feasible design. The parameters ε q l , εq l , εq l define the [20], [29].…”

Section: Case Study: Simulation Of a Powered Prosthetic Anklementioning

confidence: 99%

See 2 more Smart Citations

Robust Optimal Design of Energy Efficient Series Elastic Actuators: Application to a Powered Prosthetic Ankle

Bolívar

Rezazadeh

Summers

et al. 2019

2019 IEEE 16th International Conference on Rehabilitation Robotics (ICORR)

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Design of robotic systems that safely and efficiently operate in uncertain operational conditions, such as rehabilitation and physical assistance robots, remains an important challenge in the field. Current methods for the design of energy efficient series elastic actuators use an optimization formulation that typically assumes known operational conditions. This approach could lead to actuators that cannot perform in uncertain environments because elongation, speed, or torque requirements may be beyond actuator specifications when the operation deviates from its nominal conditions. Addressing this gap, we propose a convex optimization formulation to design the stiffness of series elastic actuators to minimize energy consumption and satisfy actuator constraints despite uncertainty due to manufacturing of the spring, unmodeled dynamics, efficiency of the transmission, and the kinematics and kinetics of the load. In our formulation, we express energy consumption as a scalar convex-quadratic function of compliance. In the unconstrained case, this quadratic equation provides an analytical solution to the optimal value of stiffness that minimizes energy consumption for arbitrary periodic reference trajectories. As actuator constraints, we consider peak motor torque, peak motor velocity, limitations due to the speed-torque relationship of DC motors, and peak elongation of the spring. As a simulation case study, we apply our formulation to the robust design of a series elastic actuator for a powered prosthetic ankle. Our simulation results indicate that a small trade-off between energy efficiency and robustness is justified to design actuators that can operate with uncertainty.

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Section: Our Contributionmentioning

confidence: 99%

Section: Case Study: Simulation Of a Powered Prosthetic Anklementioning

confidence: 99%

See 1 more Smart Citation

Robust Optimal Design of Energy Efficient Series Elastic Actuators: Application to a Powered Prosthetic Ankle

Bolívar

Rezazadeh

Summers

et al. 2019

2019 IEEE 16th International Conference on Rehabilitation Robotics (ICORR)

View full text Add to dashboard Cite

show abstract

“…Series elastic actuators (SEA) with their compliant properties are a popular choice for lower limb exoskeletons [1]- [4], humanoid robots [5], [6], and powered prostheses [7]- [10]. However, despite their regular use for robots involved in locomotion, the control of SEAs used for locomotion remains challenging.…”

Section: Introductionmentioning

confidence: 99%

“…A similar approach was used for a prostheses emulator by Caputo et al [9]. Other exoskeleton or prostheses approaches for SEA control mostly suffer from low bandwidth [1], [7], only demonstrate torque tracking for low torques in the range of 0.5-8 Nm [3], [14], or give little information about the controller used [3], [4], [10]. Besides using feedback controllers, for prostheses, a viable option is also pure feedforward control [8].…”

Section: Introductionmentioning

confidence: 99%

An Improved Force Controller With Low and Passive Apparent Impedance for Series Elastic Actuators

Rampeltshammer

Keemink

Kooij

2020

IEEE/ASME Trans. Mechatron.

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This work presents a force controller for series elastic actuators that are used in gait robots such as exoskeletons, prostheses, and humanoid robots. Therefore, the controller needs to increase the bandwidth of the actuator, lower its apparent impedance for disturbance rejection or effortless interaction with a human user, and to stably interact with any (dynamic) environment. For gait, these environments are changing discontinuously, thus creating regular impacts. In this work, we propose the use of an inner loop PD controller to increase the bandwidth of the actuator, alongside an outer loop disturbance observer (DOB) to lower the apparent impedance of the actuator. To increase the controlled bandwidth of the actuator, we introduce a novel tuning method for the PD controller that allows for independent tuning of bandwidth and damping ratio of the controlled plant. The DOB, which is introduced to reject disturbances by lowering the apparent impedance, causes the apparent impedance to turn non-passive, resulting in potential contact and coupled instability of the actuator. To enable unconditionally stable interactions with any environment, we scale down the DOB contribution such that it lowers the apparent impedance while remaining passive. The proposed tuning method and DOB adaptation were evaluated on a test-setup by identifying the torque controller's transfer behavior and by identifying the apparent impedance of the actuator. The results of these tests showed that the proposed tuning method can separately tune bandwidth and damping ratio, while the DOB adaptation is able to trade-off the reduction of the apparent impedance with its passivity.

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Human–Machine Interfaces Based on Bioelectric Signals: A Narrative Review with a Novel System Proposal

Hayashi

Tsuji

2022

IEEJ Transactions Elec Engng

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Bioelectric signals such as electromyogram (EMG) and electroencephalogram (EEG) reflect human internal states and intended actions, and have therefore been applied to various types of human-machine interfaces. Such biosignal-based interfaces are beneficial because they not only allow intuitive control of machines, but can also support persons with disabilities. In this paper, we review the recent studies on human-machine interfaces based on bioelectric signals including EMG and EEG signals. Furthermore, we introduce our recent work on the development of a brain-machine interface for domestic appliance control.

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Design and Characterization of an Open-Source Robotic Leg Prosthesis

Cited by 69 publications

References 33 publications

Robust Optimal Design of Energy Efficient Series Elastic Actuators: Application to a Powered Prosthetic Ankle

Robust Optimal Design of Energy Efficient Series Elastic Actuators: Application to a Powered Prosthetic Ankle

An Improved Force Controller With Low and Passive Apparent Impedance for Series Elastic Actuators

Human–Machine Interfaces Based on Bioelectric Signals: A Narrative Review with a Novel System Proposal

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