| 13:30 - 13:45 |
Nnamdi Chikere |
Sensitivity Analysis of Coupled Hopf Oscillator Dynamics for Controlled Flipper-Driven Robotic Locomotion |
While sea turtle hatchlings possess flippers finely tuned for efficient aquatic propulsion, these limbs must also manage effective traversal of loose terrestrial substrates during their essential journey from nest to ocean. Hatchling's ability to generate rapid, coordinated, cyclic, and repeatable flipper-driven strokes on yielding terrain has inspired robotic systems designed to operate in similarly deformable environments. Central Pattern Generators (CPGs), modeled after the neural circuits that produce rhythmic motion in animals, provide a biologically grounded framework for coordinating these cyclic limb movements.
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While sea turtle hatchlings possess flippers finely tuned for efficient aquatic propulsion, these limbs must also manage effective traversal of loose terrestrial substrates during their essential journey from nest to ocean. Hatchling's ability to generate rapid, coordinated, cyclic, and repeatable flipper-driven strokes on yielding terrain has inspired robotic systems designed to operate in similarly deformable environments. Central Pattern Generators (CPGs), modeled after the neural circuits that produce rhythmic motion in animals, provide a biologically grounded framework for coordinating these cyclic limb movements. Identifying the CPG parameters that most strongly influence locomotor performance is essential for developing adaptive and energy-efficient gait controllers. In this study, we present a detailed parameter-sensitivity analysis of a Hopf-oscillator Central Pattern Generator (CPG) that drives a sea-turtle-inspired robot in a MuJoCo simulation environment. We performed systematic sweeps of key CPG parameters, including stance and swing frequencies, amplitude gains, and inter-oscillator coupling strength, quantifying their effects on forward speed, mechanical energy expenditure, and the cost of transport. The results demonstrate that stance frequency is the dominant determinant of forward propulsion, with speed rapidly increasing up to approximately 1.0-1.1Hz before saturating. Amplitude analysis showed that foreflipper amplitude is crucial, producing over a twofold speed increase, while hindflipper and hip amplitudes primarily influence stability and energy consumption. Furthermore, the coupling strength was found to strongly modulate the quality of flipper coordination. Overall, these findings identify the key CPG parameters governing robust flipper-based locomotion on yielding terrain, providing critical insight for future optimization and adaptive control strategies in bio-inspired robotics.
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| 13:45 - 14:00 |
Muqun Hu |
Towards Versatile Humanoid Table Tennis: Unified RL with Prediction Augmentation |
Humanoid table tennis (TT) demands rapid perception, proactive whole-body motion, and agile footwork under strict timing -- capabilities that remain difficult for unified controllers. We propose a reinforcement learning framework that maps ball-position observations directly to whole-body joint commands for both arm striking and leg locomotion, strengthened by predictive signals and dense, physics-guided rewards. A lightweight learned predictor, fed with recent ball positions, estimates future ball states and augments the policy's observations for proactive decision-making.
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Humanoid table tennis (TT) demands rapid perception, proactive whole-body motion, and agile footwork under strict timing -- capabilities that remain difficult for unified controllers. We propose a reinforcement learning framework that maps ball-position observations directly to whole-body joint commands for both arm striking and leg locomotion, strengthened by predictive signals and dense, physics-guided rewards. A lightweight learned predictor, fed with recent ball positions, estimates future ball states and augments the policy's observations for proactive decision-making. During training, a physics-based predictor supplies precise future states to construct dense, informative rewards that lead to effective exploration. The resulting policy attains strong performance across varied serve ranges (hit rate ≥ 96% and success rate ≥ 92%) in simulations. Ablation studies confirm that both the learned predictor and the predictive reward design are critical for end-to-end learning. Deployed zero-shot on a physical Booster T1 humanoid with 23 revolute joints, the policy produces coordinated lateral and forward-backward footwork with accurate, fast returns, suggesting a practical path toward versatile, competitive humanoid TT.
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| 14:00 - 14:15 |
Zhixian Hu |
Vibrissae-Inspired Vision-Based Magnetic-Actuated Whisker |
Tactile perception is significant for robotic operation in unstructured environments. Whisker-based sensors offer lightweight bio-inspired solutions, yet most rely on single-whisker sensing and are limited by passive interaction and constrained functionality. Here we present a circular array of eight independently actuated whiskers, each driven by a pulse-switchable permanent magnet and tracked by a camera. This design enables simultaneous multi-point sensing and coordinated actuation, supporting diverse functions.
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Tactile perception is significant for robotic operation in unstructured environments. Whisker-based sensors offer lightweight bio-inspired solutions, yet most rely on single-whisker sensing and are limited by passive interaction and constrained functionality. Here we present a circular array of eight independently actuated whiskers, each driven by a pulse-switchable permanent magnet and tracked by a camera. This design enables simultaneous multi-point sensing and coordinated actuation, supporting diverse functions. Quantitative analyses demonstrate accurate pixel-to-physical mapping, consistent pixel-to-force characterization, and long-term repeatability. In this work, we show that an vibrissae-inspired vision-based magnetic-actuated whisker array integrating distributed perception with active interaction achieves reliable physical mapping, repeatable sensing, and delicate grasping, thereby advancing tactile sensing and laying the foundation for contact-driven exploration, soft manipulation, and adaptive behavior in dynamic environments.
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| 14:15 - 14:30 |
I-Chia Chang |
Adaptive Control for Humanoid Locomotion under Hybrid Dynamics on Multi-directional Moving Platforms |
Achieving stable humanoid walking on moving platforms with unknown motion remains a challenging control problem due to the hybrid dynamics involving time-varying unknown disturbance. Adaptive control is a widely used method for rejecting such disturbances, yet existing adaptive controllers are typically designed for continuous-time system and do not directly applicable for hybrid systems. This work develops an adaptive controller capable of rejecting multiple sinusoidal disturbances with unknown frequencies, amplitudes, and phases for a linear hybrid system.
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Achieving stable humanoid walking on moving platforms with unknown motion remains a challenging control problem due to the hybrid dynamics involving time-varying unknown disturbance. Adaptive control is a widely used method for rejecting such disturbances, yet existing adaptive controllers are typically designed for continuous-time system and do not directly applicable for hybrid systems. This work develops an adaptive controller capable of rejecting multiple sinusoidal disturbances with unknown frequencies, amplitudes, and phases for a linear hybrid system. First, we show that this disturbance rejection problem is solvable given the solution to the hybrid regulator equation exists. Second, we propose an output feedback controller structure and prove that at least one set of controller parameters achieves exact disturbance rejection. Third, using hybrid swapping lemma, we construct a parameter estimation law to adjust the controller parameters using a least-square-type adaptive law. Finally, we treat the humanoid walking on moving surfaces as a case study to validate the usefulness of the proposed method. Both simulation and experiments confirm the performance improvement through an ablation study.
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| 14:30 - 14:45 |
Shengqing Xia |
Robotic and Autonomous Systems |
Autonomous drone delivery to door relies on a popular computer vision technique called semantic segmentation (SS) to recognize meaningful house segments and determine a precise drop-off point near the door. While this SS-based approach is effective under specific environments, it fails to perform well across other common environmental factors such as different seasons, hours of the day, weather and illumination levels. In this work, we propose Robust Structural Semantic Segmentation (RSSS), a novel patch to the existing SS solution without requiring re-training for new environments.
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Autonomous drone delivery to door relies on a popular computer vision technique called semantic segmentation (SS) to recognize meaningful house segments and determine a precise drop-off point near the door. While this SS-based approach is effective under specific environments, it fails to perform well across other common environmental factors such as different seasons, hours of the day, weather and illumination levels. In this work, we propose Robust Structural Semantic Segmentation (RSSS), a novel patch to the existing SS solution without requiring re-training for new environments. The core idea is to “Let Strong Help Weak”, where the results of semantic segmentation obtained under favorable/strong conditions are utilized to enhance the weaker ones in adverse settings. This improvement is achieved by leveraging house structures and spatial layouts, which remain largely invariant across various environments. Our evaluation shows that RSSS outperforms the state-of-the-art methods and significantly enhances the robustness of SS and drone delivery across various environments.
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| 14:45 - 15:00 |
Shijun Zhou |
Energy-efficient Intermittent Gliding Flight Control of a Bird-scale Flapping Wing Vehicle using Dynamic Soaring |
In this conference, we would like to demonstrate a bio-inspired flight controller and robotic platform that enables bird-scale flapping wing vehicles to have longer, and more efficient flights. In nature, we often see seagulls and albatrosses gliding (without flapping) effortlessly in gusts of wind near the seashore. Birds such as albatrosses are able to fly tirelessly for days without needing to rest. The secret lies in the unique flight pattern called “Dynamic Soaring”. By utilizing the wind shear layers above the ocean surface and their aerodynamic body structure, seagulls and albatrosses are able to easily gain altitude without expending energy (through active flapping).
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In this conference, we would like to demonstrate a bio-inspired flight controller and robotic platform that enables bird-scale flapping wing vehicles to have longer, and more efficient flights. In nature, we often see seagulls and albatrosses gliding (without flapping) effortlessly in gusts of wind near the seashore. Birds such as albatrosses are able to fly tirelessly for days without needing to rest. The secret lies in the unique flight pattern called “Dynamic Soaring”. By utilizing the wind shear layers above the ocean surface and their aerodynamic body structure, seagulls and albatrosses are able to easily gain altitude without expending energy (through active flapping). Unconventionally, by treating the wind gusts as means to lower their total energy output instead of treating them as disturbance, albatrosses can perform energy efficient endurance flights. Inspired by dynamic soaring and its unique application in increasing flight efficiency, we will propose a new bio-inspired flapping wing vehicle platform with a flight control scheme in this conference and provide live demonstrations of this new experimental platform.
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