{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2026:47WNB7WT2MD7TZL4LTO6CPFJSB","short_pith_number":"pith:47WNB7WT","schema_version":"1.0","canonical_sha256":"e7ecd0fed3d307f9e57c5cdde13ca9905be4c147835915280f7073b24da67c0e","source":{"kind":"arxiv","id":"2606.21866","version":1},"attestation_state":"computed","paper":{"title":"SurGE: Surrogate Gradient-guided Evolution for Co-design of Legged Robots with Parallel Elasticity","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cs.RO","authors_text":"Justin Lu, Sicheng He, Yanran Ding, Yichen Wang, Yue Qin, Yulun Zhuang, Zelin Shen","submitted_at":"2026-06-20T04:09:24Z","abstract_excerpt":"Co-design of legged robots with elastic elements is challenging due to the non-differentiability of contact dynamics and mechanism engagement. This paper presents SurGE, a framework that computes surrogate gradients of the design objective through a differentiable pipeline consisting of a kinodynamic single-rigid-body (Kino-SRB) model and a design-aware control policy, and injects them into CMA-ES via mean shift with cosine-annealed step decay. On a 4-DOF design space of a hopping robot with unidirectional parallel spring, SurGE achieves 6 times lower cross-seed standard deviation and 18% tigh"},"verification_status":{"content_addressed":true,"pith_receipt":true,"author_attested":false,"weak_author_claims":0,"strong_author_claims":0,"externally_anchored":false,"storage_verified":false,"citation_signatures":0,"replication_records":0,"graph_snapshot":true,"references_resolved":false,"formal_links_present":false},"canonical_record":{"source":{"id":"2606.21866","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.RO","submitted_at":"2026-06-20T04:09:24Z","cross_cats_sorted":[],"title_canon_sha256":"0d1d7ebabc5e976bbe495d3b3e7232fb617ad89d61f6ad04a70b1667466f7345","abstract_canon_sha256":"8d204401a96f27a0093d63b837423d37ca5623e5fab4ba29f3bc83b685713a9e"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-06-23T02:13:01.398102Z","signature_b64":"3EWC+c/IJqfPcQQCHcNlUW6ZcUf9NkB4N00JTfWtT8si5tuWq2pXWVw8ilyTWBUWlYQE0ilG/Be3+0MCSs1aAA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"e7ecd0fed3d307f9e57c5cdde13ca9905be4c147835915280f7073b24da67c0e","last_reissued_at":"2026-06-23T02:13:01.397665Z","signature_status":"signed_v1","first_computed_at":"2026-06-23T02:13:01.397665Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"SurGE: Surrogate Gradient-guided Evolution for Co-design of Legged Robots with Parallel Elasticity","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cs.RO","authors_text":"Justin Lu, Sicheng He, Yanran Ding, Yichen Wang, Yue Qin, Yulun Zhuang, Zelin Shen","submitted_at":"2026-06-20T04:09:24Z","abstract_excerpt":"Co-design of legged robots with elastic elements is challenging due to the non-differentiability of contact dynamics and mechanism engagement. This paper presents SurGE, a framework that computes surrogate gradients of the design objective through a differentiable pipeline consisting of a kinodynamic single-rigid-body (Kino-SRB) model and a design-aware control policy, and injects them into CMA-ES via mean shift with cosine-annealed step decay. On a 4-DOF design space of a hopping robot with unidirectional parallel spring, SurGE achieves 6 times lower cross-seed standard deviation and 18% tigh"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2606.21866","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2606.21866/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"aliases":[{"alias_kind":"arxiv","alias_value":"2606.21866","created_at":"2026-06-23T02:13:01.397724+00:00"},{"alias_kind":"arxiv_version","alias_value":"2606.21866v1","created_at":"2026-06-23T02:13:01.397724+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2606.21866","created_at":"2026-06-23T02:13:01.397724+00:00"},{"alias_kind":"pith_short_12","alias_value":"47WNB7WT2MD7","created_at":"2026-06-23T02:13:01.397724+00:00"},{"alias_kind":"pith_short_16","alias_value":"47WNB7WT2MD7TZL4","created_at":"2026-06-23T02:13:01.397724+00:00"},{"alias_kind":"pith_short_8","alias_value":"47WNB7WT","created_at":"2026-06-23T02:13:01.397724+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":0,"internal_anchor_count":0,"sample":[]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/47WNB7WT2MD7TZL4LTO6CPFJSB","json":"https://pith.science/pith/47WNB7WT2MD7TZL4LTO6CPFJSB.json","graph_json":"https://pith.science/api/pith-number/47WNB7WT2MD7TZL4LTO6CPFJSB/graph.json","events_json":"https://pith.science/api/pith-number/47WNB7WT2MD7TZL4LTO6CPFJSB/events.json","paper":"https://pith.science/paper/47WNB7WT"},"agent_actions":{"view_html":"https://pith.science/pith/47WNB7WT2MD7TZL4LTO6CPFJSB","download_json":"https://pith.science/pith/47WNB7WT2MD7TZL4LTO6CPFJSB.json","view_paper":"https://pith.science/paper/47WNB7WT","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=2606.21866&json=true","fetch_graph":"https://pith.science/api/pith-number/47WNB7WT2MD7TZL4LTO6CPFJSB/graph.json","fetch_events":"https://pith.science/api/pith-number/47WNB7WT2MD7TZL4LTO6CPFJSB/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/47WNB7WT2MD7TZL4LTO6CPFJSB/action/timestamp_anchor","attest_storage":"https://pith.science/pith/47WNB7WT2MD7TZL4LTO6CPFJSB/action/storage_attestation","attest_author":"https://pith.science/pith/47WNB7WT2MD7TZL4LTO6CPFJSB/action/author_attestation","sign_citation":"https://pith.science/pith/47WNB7WT2MD7TZL4LTO6CPFJSB/action/citation_signature","submit_replication":"https://pith.science/pith/47WNB7WT2MD7TZL4LTO6CPFJSB/action/replication_record"}},"created_at":"2026-06-23T02:13:01.397724+00:00","updated_at":"2026-06-23T02:13:01.397724+00:00"}