{"doi":"10.1109/tbme.2025.3540625","title":"Design and Evaluation of a Sensor-Instrumented Clutch Mechanism for Quasi-Passive Back Exosuits","abstract":"OBJECTIVE: We designed, built, and evaluated a new sensor-instrumented clutch to expand the capabilities of quasi-passive back exos (exoskeletons and exosuits) to include force sensing, posture sensing, and versatile mode switching. Quasi-passive back exos provide workers with lifting assistance, which can reduce their back injury risk. Central to their design is a clutch mechanism that enables the exo to assist when engaged and be unobstructive when disengaged. However, current exo clutches can have limited sensing and control capabilities. DESIGN AND METHODS: We designed a new clutch that integrates an encoder, solenoid, inertial measurement unit, and microprocessor to estimate exo assistance, monitor posture, and switch between engaged and disengaged modes. To validate the new capabilities, 6 participants wore a back exo during stoop and squat tasks. Data from the clutch's encoder were used to estimate assistance and trunk-thigh flexion angle, then compared to motion analysis lab measurements. RESULTS: The prototype estimated exo assistance with an average error of 8.8 N (0.9 Nm of lumbar torque) and trunk-thigh angle with an average error of 6.7°. This prototype also maintained the core capabilities of a quasi-passive exo by withstanding 350 N of force when the clutch was engaged, exerting 7-20 N when disengaged, and switching between clutch modes in 0.1 seconds. CONCLUSION: We demonstrated an instrumented clutch that enabled exo assistance and posture monitoring, and more versatile control options, in addition to providing back relief. SIGNIFICANCE: This clutch increases the capabilities of quasi-passive back exos, opening new opportunities for exo research and applications.","journal":"IEEE Transactions on Biomedical Engineering","year":2025,"id":538768,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":3,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9544,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":746251,"name":"Shane T. King","orcid":"0000-0001-7187-7043","position":1,"is_corresponding":false},{"id":640974,"name":"Cameron A. Nurse","orcid":"0000-0001-7296-7550","position":2,"is_corresponding":false},{"id":1426029,"name":"Chad Ice","orcid":null,"position":3,"is_corresponding":false},{"id":545841,"name":"Michael Goldfarb","orcid":"0000-0002-6622-095X","position":4,"is_corresponding":false},{"id":286161,"name":"Karl E. Zelik","orcid":"0000-0002-5054-2479","position":5,"is_corresponding":false},{"id":1425626,"name":"Paul Slaughter","orcid":"0000-0003-1854-1713","position":0,"is_corresponding":true}],"reference_count":32,"raw_metadata":null,"created_at":"2026-07-19T02:52:25.799399Z","pmid":"40031841","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}