{"schema_version":"1.0","canonical_url":"https://patentable.app/patents/US-9691421","patent":{"patent_number":"US-9691421","title":"Writing spirals with accurate slope on a disk drive media","assignee":null,"inventors":[],"filing_date":"2015-03-31T00:00:00.000Z","publication_date":"2017-06-27T00:00:00.000Z","cpc_codes":["G11B","G11B","G11B"],"num_claims":21,"abstract":"A reference spiral is written on a recording surface of a magnetic storage disk that is free of position or timing information. The reference spirals are written on the recording surface with a substantially uniform slope by using open loop control of the position of a read/write head in conjunction with an iterative learning control scheme. A voltage profile applied to a voice coil motor is adapted over multiple iterations of moving the read/write head across the recording surface to closely approximate a target voltage profile, and the reference spiral is written using the adapted voltage profile. In addition, ramp contact detection based on actuator current profile may be employed to achieve full utilization of available actuator stroke."},"analysis":{"summary":null,"layman_explanation":null,"technical_analysis":null,"business_analysis":null,"faqs":null,"topics":[],"tech_cluster":null},"seo":{"title":"Writing spirals with accurate slope on a disk drive media","description":"A reference spiral is written on a recording surface of a magnetic storage disk that is free of position or timing information. The reference spirals are written on the recording surface with a substa","keywords":[]},"attribution":{"source":"Patentable","source_url":"https://patentable.app","canonical_url":"https://patentable.app/patents/US-9691421","license":"CC-BY-4.0-like","license_terms":"AI-generated analysis on this page (summary, layman_explanation, technical_analysis, business_analysis, faqs) may be reused with attribution and a visible link back to the canonical URL above. Patent abstracts, claims, and bibliographic data are USPTO public domain.","required_link":"https://patentable.app/patents/US-9691421","citation_suggestion":"Patentable. \"Writing spirals with accurate slope on a disk drive media\" (US-9691421). https://patentable.app/patents/US-9691421","copyright_holder":"Nomic Interactive Technology LLC"},"links":{"html":"https://patentable.app/patents/US-9691421","json":"https://patentable.app/api/llm-context/US-9691421","site":"https://patentable.app","llms_txt":"https://patentable.app/llms.txt"},"generated_at":"2026-06-06T13:18:30.437Z"}