High-Stiffness Control of Series Elastic Actuators Using a Noise Reduction Disturbance Observer

Asignacion, Abner; Haninger, Kevin; Oh, Sehoon; Lee, Hyunwook

doi:10.1109/tie.2021.3106016

Cited by 13 publications

(10 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Generally speaking, DOB-based force controllers aim to enforce a nominal model P n (s) to the force dynamics despite environment uncertainties and unmodelled disturbances. DOB-based force control of SEAs is an established research topic [7,13,25,26,31]. Different solutions have been proposed which can be classified as:…”

Section: Environment Aware Friction Observermentioning

confidence: 99%

See 1 more Smart Citation

Environment Aware Friction Observer with Applications to Force Control Benchmarking

Dimo,

Calanca

2024

Actuators

View full text Add to dashboard Cite

The benchmarking of force control algorithms has been significantly investigated in recent years. High-fidelity experimental benchmarking outcomes may require high-end electronics and mechanical systems not to compromise the algorithm’s evaluation. However, affordability may be highly desired to spread benchmarking tools within the research community. Mechanical inaccuracies due to affordability can lead to undesired friction effects which in this paper are tackled by exploiting a novel friction compensation technique based on an environment-aware friction observer (EA-FOB). Friction compensation capabilities of the proposed EA-FOB are assessed through simulation and experimental comparisons with a widely used static friction model: Coulomb friction combined with viscous friction. Moreover, a comprehensive stability comparison with state-of-the-art disturbance observers (DOBs) is conducted. Results show higher stability margins for the EA-FOB with respect to traditional DOBs. The research is carried on within the Forecast project, which aims to provide tools and metrics to benchmark force control algorithms relying on low-cost electronics and affordable hardware.

show abstract

Section: Environment Aware Friction Observermentioning

confidence: 99%

“…Oh et al recently proposed using a two-mass SEA nominal model that neglects the interaction forces with the environment but includes the link dynamics [31,35]. This case is equivalent to considering:…”

Section: Nominal Plant With Link Dynamics (Ld-dob)mentioning

confidence: 99%

Environment Aware Friction Observer with Applications to Force Control Benchmarking

Dimo,

Calanca

2024

Actuators

View full text Add to dashboard Cite

show abstract

“…This increase, however, comes at the cost of calculation time, which is a trade-off between accuracy of the planner and its use in fast trajectory adaptations. A similar problem is posed by the adjusted foot placement during 4 86 4 An optimal and versatile trajectory generation for lower limb exoskeletons ramp ascend. The step target has to be parallel to even terrain to make sure that the subsequent weight shift converges to a solution.…”

Section: Discussionmentioning

confidence: 99%

“…Oh et al [84] and Lee et al [85] included the immediate load side dynamics in the inner loop DOB for better tracking accuracy. Asignacion et al [86] used a DOB variation alongside a cascaded PD controller, similar to Vallery et al [31]. Ahn et al [81] demonstrated that inner loop DOB controllers are robust for SEAs with high damping (i.e., viscoelastic actuators) using perturbation theory analysis [87].…”

Section: State Of the Artmentioning

confidence: 99%

“…Controllers are evaluated based on locked output torque tracking performance, their disturbance rejection (i.e., magnitude of the apparent impedance), their interaction stability (i.e., passivity of the apparent impedance, as well as their noise sensitivity). With this structured analysis, it is possible to select controllers specifically based on application requirements, such as bandwidth requirements, sensor noise levels [86], and interaction types (e.g., low apparent impedance if in direct interaction with humans or unconditional interaction stability in case of uncertain interactions).…”

Section: Our Approachmentioning

confidence: 99%

See 1 more Smart Citation