<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>Deep Reinforcement Learning |</title><link>https://abhinavj98.github.io/tags/deep-reinforcement-learning/</link><atom:link href="https://abhinavj98.github.io/tags/deep-reinforcement-learning/index.xml" rel="self" type="application/rss+xml"/><description>Deep Reinforcement Learning</description><generator>HugoBlox Kit (https://hugoblox.com)</generator><language>en-us</language><lastBuildDate>Tue, 01 Sep 2026 00:00:00 +0000</lastBuildDate><image><url>https://abhinavj98.github.io/media/icon.svg</url><title>Deep Reinforcement Learning</title><link>https://abhinavj98.github.io/tags/deep-reinforcement-learning/</link></image><item><title>Visuomotor Robotic Pruning in Planar Orchards Using Hybrid Reinforcement Learning</title><link>https://abhinavj98.github.io/publications/visuomotor/</link><pubDate>Tue, 01 Sep 2026 00:00:00 +0000</pubDate><guid>https://abhinavj98.github.io/publications/visuomotor/</guid><description>&lt;h2 id="watch-the-demo"&gt;Watch the Demo&lt;/h2&gt;
&lt;p&gt;See the visuomotor policy achieving zero-shot sim-to-real transfer in real commercial and experimental orchards:&lt;/p&gt;
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&lt;h2 id="abstract"&gt;Abstract&lt;/h2&gt;
&lt;p&gt;Dormant tree pruning is labor-intensive yet essential for maintaining modern high-productivity fruit orchards. In this work, we focus on pruning of modern planar tree training systems—V-Trellis apples and UFO cherries—where trunks and primary branches are trained into approximately planar walls. We introduce an &lt;strong&gt;end-to-end pipeline&lt;/strong&gt; to learn a closed-loop visuomotor controller for robotic pruning, trained entirely in simulation and deployed in real orchards &lt;strong&gt;zero-shot&lt;/strong&gt;.&lt;/p&gt;
&lt;p&gt;Key contributions:&lt;/p&gt;
&lt;ul&gt;
&lt;li&gt;&lt;strong&gt;Novel orchard simulator&lt;/strong&gt;: Physics-based PyBullet environment with synthetically generated planar orchard tree meshes (Tree-L-Py)&lt;/li&gt;
&lt;li&gt;&lt;strong&gt;Automated demonstration generation&lt;/strong&gt;: Motion planning pipeline (RRT-Connect) to collect successful pruning trajectories as offline data&lt;/li&gt;
&lt;li&gt;&lt;strong&gt;Hybrid-PPO&lt;/strong&gt;: A novel hybrid reinforcement-learning algorithm combining offline expert demonstrations with online PPO rollouts&lt;/li&gt;
&lt;li&gt;&lt;strong&gt;Optical-flow perception&lt;/strong&gt;: Avoids 3D reconstruction; wrist-mounted camera optical flow enables strong sim-to-real generalization&lt;/li&gt;
&lt;li&gt;&lt;strong&gt;Real-world validation&lt;/strong&gt;: 38 physical trials (28 outdoor field trials in commercial orchards + 10 indoor lab tests) with zero-shot sim-to-real transfer; outperforms RRT-Connect baseline on hardware&lt;/li&gt;
&lt;/ul&gt;
&lt;p&gt;&lt;strong&gt;Simulation results&lt;/strong&gt;: 49.9% success on V-Trellis apples and 46.0% on UFO cherries (3,000 cutpoints). &lt;strong&gt;Real-world results&lt;/strong&gt;: 71% success on V-Trellis apples in outdoor commercial orchards.&lt;/p&gt;</description></item></channel></rss>