Harvard's GRASP recovers gradients from archived rollouts for dexterous retargeting

hankyang94 · x · 2026-11-01

Harvard's Computational Robotics Group details GRASP, building on their RSS 2026 TSMC work: it combines sampling-based exploration with gradient-guided refinement without requiring differentiable simulator dynamics. The key trick is reusing archived rollouts (including rejected proposals) to fit local cost models and recover gradients — even simple quadratic surrogates help guide MCMC rejuvenation. A Metropolis–Hastings correction with true simulator costs preserves the cost-tilted target distribution, and an MPC formulation extends the optimizer to long demonstrations. GRASP achieves 94.2% success on 1,352 bimanual OakInk2 demonstrations with Sharpa hands, with 2.87 cm mean object position error.

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