Uploaded May 2018 | Updated September 2026, 2 weeks ago
ICRA 2018 Spotlight Video
Interactive Session Thu PM Pod I.3
Authors: Yi, Daqing; Thakker, Rohan; Gulino, Cole; Salzman, Oren; Srinivasa, Siddhartha
Title: Generalizing Informed Sampling for Asymptotically Optimal Sampling-Based Kinodynamic Planning Via Markov Chain Monte Carlo
Abstract:
Asymptotically-optimal motion planners such as RRT* have been shown to incrementally approximate the shortest path between start and goal states. Once an initial solution is found, their performance can be dramatically improved by restricting subsequent samples to regions of the state space that can potentially improve the current solution. When the motion planning problem lies in a Euclidean space, this region, called the informed set, can be sampled directly. However, when planning with differential constraints in non-Euclidean state spaces, no analytic solutions exists to sampling the informed sampling directly. State-of-the-art approaches to sampling an informed set in such domains such as Hierarchical Rejection Sampling (HRS) may still be slow in high-dimensional state space. This may cause the planning algorithm to spend most of its time trying to produces samples rather than explore it. In this paper, we suggest an alternative approach to produce samples in the informed set for a wide range of settings. Our main insight is to recast this problem as one of sampling uniformly within the sub-level-set of an implicit non-convex function. This recasting enables us to apply Monte Carlo sampling methods to solve our problem. We show for a wide range of scenarios that using our sampler can accelerate the convergence rate to high-quality solutions in high-dimensional problems.
ICRA 2018 Spotlight Video
Interactive Session Thu PM Pod I.3
Authors: Yi, Daqing; Thakker, Rohan; Gulino, Cole; Salzman, Oren; Srinivasa, Siddhartha
Title: Generalizing Informed Sampling for Asymptotically Optimal Sampling-Based Kinodynamic Planning Via Markov Chain Monte Carlo
Abstract:
Asymptotically-optimal motion planners such as RRT* have been shown to incrementally approximate the shortest path between start and goal states. Once an initial solution is found, their performance can be dramatically improved by restricting subsequent samples to regions of the state space that can potentially improve the current solution. When the motion planning problem lies in a Euclidean space, this region, called the informed set, can be sampled directly. However, when planning with differential constraints in non-Euclidean state spaces, no analytic solutions exists to sampling the informed sampling directly. State-of-the-art approaches to sampling an informed set in such domains such as Hierarchical Rejection Sampling (HRS) may still be slow in high-dimensional state space. This may cause the planning algorithm to spend most of its time trying to produces samples rather than explore it. In this paper, we suggest an alternative approach to produce samples in the informed set for a wide range of settings. Our main insight is to recast this problem as one of sampling uniformly within the sub-level-set of an implicit non-convex function. This recasting enables us to apply Monte Carlo sampling methods to solve our problem. We show for a wide range of scenarios that using our sampler can accelerate the convergence rate to high-quality solutions in high-dimensional problems.







![Learning to Parse Natural Language to Grounded Reward Functions with Weak Supervision
ICRA 2018 Spotlight Video
Interactive Session Wed PM Pod I.1
Authors: Williams, Edward; Gopalan, Nakul; Rhee, Mina; Tellex, Stefanie
Title: Learning to Parse Natural Language to Grounded Reward Functions with Weak Supervision
Abstract:
In order to intuitively and efficiently collaborate with humans, robots must learn to complete tasks specified using natural language. We represent natural language instructions as goal-state reward functions specified using lambda calculus. Using reward functions as language representations allows robots to plan efficiently in stochastic environments. To map sentences to such reward functions, we learn a weighted linear Combinatory Categorial Grammar (CCG) semantic parser. The parser, including both parameters and the CCG lexicon, is learned from a validation procedure that does not require execution of a planner, annotating reward functions, or labeling parse trees, unlike prior approaches. To learn a CCG lexicon and parse weights, we use coarse lexical generation and validation-driven perceptron weight updates using the approach of Artzi and Zettlemoyer [4]. We present results on the Cleanup World domain [19] to demonstrate the potential of our approach. We report an F1 score of 0.82 on a collected corpus of 23 tasks containing combinations of nested referential expressions, comparators and object properties with 2037 corresponding sentences. Our goal-condition learning approach enables an improvement of orders of magnitude in computation time over a baseline that performs planning during learning, while achieving comparable results. Further, we conduct an experiment with just 6 labeled demonstrations to show the ease of teaching a robot behaviors using our method. Learning to Parse Natural Language to Grounded Reward Functions with Weak Supervision](https://i.ytimg.com/vi/c9Up1R_jlew/mqdefault.jpg)


