Recently, quantitative and repetitive inspections of the old urban area were conducted because many structures exceed their designed lifetime. The health of a building can be validated from the condition of the outer ...
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The disposal and recycling of electronic waste (e-waste) poses a significant global challenge. The disassembly of components is a crucial step in achieving an efficient recycling process, avoiding destructive methods....
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High-intensity pulsed laser-material interaction is a complicated process involving various laser parameters and material properties, and the coupling of these factors affects material modifications. This study invest...
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Combined with demonstrations, deep reinforcement learning can efficiently develop policies for manipulators. However, it takes time to collect sufficient high-quality demonstrations in practice. And human demonstratio...
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Modern robotic manipulation systems fall short of human manipulation skills partly because they rely on closing feedback loops exclusively around vision data, which reduces system bandwidth and speed. By developing au...
Modern robotic manipulation systems fall short of human manipulation skills partly because they rely on closing feedback loops exclusively around vision data, which reduces system bandwidth and speed. By developing autonomous grasping reflexes that rely on high-bandwidth force, contact, and proximity data, the overall system speed and robustness can be increased while reducing reliance on vision data. We are developing a new system built around a low-inertia, high-speed arm with nimble fingers that combines a high-level trajectory planner operating at less than 1 Hz with low-level autonomous reflex controllers running upwards of 300 Hz. We characterize the reflex system by comparing the volume of the set of successful grasps for a naive baseline controller and variations of our reflexive grasping controller, finding that our controller expands the set of successful grasps by 55% relative to the baseline. We also deploy our reflexive grasping controller with a simple vision-based planner in an autonomous clutter clearing task, achieving a grasp success rate above 90% while clearing over 100 items.
The Spring-Loaded Inverted Pendulum (SLIP) is one of the simplest models of robot locomotion. SLIP is commonly used to predict the center of mass motion and derive simple control laws for stable locomotion. However, t...
The Spring-Loaded Inverted Pendulum (SLIP) is one of the simplest models of robot locomotion. SLIP is commonly used to predict the center of mass motion and derive simple control laws for stable locomotion. However, the SLIP model is not integrable, which means that no closed-form relation can be derived to understand how the design and control parameters of the SLIP model affect stable locomotion. There exist a number of different analytical approximations to the SLIP model when considering small step lengths and symmetric steps. In this paper, we present a novel approximation to the SLIP model without relying on the small step length and the symmetric step assumption. The model was found to accurately predict the stability of the SLIP model for large and asymmetric steps and was used to design a controller to stabilize the SLIP model in a couple of steps.
A miniature haptic stimulation device utilizes focused ultrasound to deliver a tactile haptic sensation to the finger. The 1-3 piezocomposite device has a 1 cm 2 footprint, which is an order of magnitude smaller than...
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ISBN:
(数字)9798350384574
ISBN:
(纸本)9798350384581
A miniature haptic stimulation device utilizes focused ultrasound to deliver a tactile haptic sensation to the finger. The 1-3 piezocomposite device has a 1 cm
2
footprint, which is an order of magnitude smaller than other ultrasonic haptic devices and is a good candidate for wearable tactile rendering systems. The device focuses energy to a 1 mm
3
voxel. The current prototype was validated with a small, preliminary human subject study and requires an average input voltage of 68.8 V to elicit tactile sensation. The sensory drive voltage threshold will decrease with future refinement of mechanical impedance matching and focusing.
Existing approaches to robust global asymptotic stabilization of a pair of antipodal points on unit n-sphere Sn typically involve the non-centrally synergistic hybrid controllers for attitude tracking on unit quaterni...
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The increasing use of robotic devices in clinical settings for rehabilitation and assistance underscores the need to understand their effects on muscle activation patterns. Prior studies have suggested that excessive ...
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The increasing use of robotic devices in clinical settings for rehabilitation and assistance underscores the need to understand their effects on muscle activation patterns. Prior studies have suggested that excessive assistance from robotic devices reduces voluntary control, leading to potential negative consequences on rehabilitation outcomes. However, the observation of muscle activation during exoskeleton-assisted walking in unimpaired individuals suggests the absence of adaptive responses to short-term exposure at high levels of assistance. The objective of this study is to determine whether prolonged exposure to maximum exoskeleton assistance induces adaptive changes in muscle activity and to analyze if distinct muscle activation profiles emerged during assisted versus unassisted walking. To achieve this, we performed the electromyographic analysis of eight bilateral lower limb muscles in ten participants during a one-hour training session. The results revealed a decrease in muscle activity over time. Furthermore, assisted walking exhibited distinct muscle patterns compared to unassisted walking, demonstrating that the level of assistance, along with the exoskeleton’s structure, significantly influences muscle activity. These findings hold significance for optimizing assistance regulation in exoskeleton-assisted walking, in terms of levels and timing of assistance changes, to enhance rehabilitative outcomes. Understanding how exoskeletons influence muscle activation can lead to improved rehabilitation strategies, maximizing the benefits of this technology for enhancing walking ability in people with neurological conditions or injuries.
Parallel elastic actuators (PEA) find a growing interest in many research areas ranging from rehabilitation devices to industrial robots on account of their ability to save energy as well as providing passive impact a...
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