We present results of experiments with a haptic feedback device that imparts tangential deformati... more We present results of experiments with a haptic feedback device that imparts tangential deformations to the fingertips for displaying changes in force experienced by an MR-compatible optically-instrumented biopsy needle. The display is actuated using multiple layers of MR-compatible electroactive polymers stretched in a plastic frame. Users can use the device to sense events such as membrane puncture, as the needle is driven through a tissue phantom, with 98.9% reliability.
Soft robotic hands can facilitate human–robot interaction by allowing robots to grasp a wide rang... more Soft robotic hands can facilitate human–robot interaction by allowing robots to grasp a wide range of objects safely and gently. However, their performance has been hampered by a lack of suitable sensing systems. We present a flexible and stretchable multi-modal sensor network integrated with a soft robotic hand. The design of wired sensors on a flexible metalized film was embodied through a manufacturing approach that uses both UV laser metal ablation and plastic cutting simultaneously to create sensor electrode and stretchable conductive wires in a Kirigami pattern into a single network. We evaluated the interconnects and sensors by measuring an impedance change to each external stimulus and showed that are not substantially affected by stretching the network. With the sensor sheet wrapped around a soft robotic gripper, we demonstrated several interaction scenarios, including a warm burrito for food handling, and a warm baby doll for medical applications.
The International Journal of Robotics Research, 2018
This paper presents models of arrays of compliantly supported spines that attach to rough surface... more This paper presents models of arrays of compliantly supported spines that attach to rough surfaces. The applications include climbing and perching robots. Surfaces are characterized in terms of asperity distributions, which lead to stochastic models of spine force capabilities over a range of loading directions. Models cover unidirectional spine arrays and pairs of opposed arrays that withstand normal forces pulling away from a surface. Experiments on a variety of surfaces confirm the predicted behavior. For opposed spine arrays, the overall load capability also depends on the preloading strategy for applying internal forces. Insights from the analysis guide the design of spine array mechanisms to allow, for example, a small aerial platform to attach to walls and ceilings.
Micro-aerial vehicles (MAVs) face limited flight times, which adversely impacts their efficacy fo... more Micro-aerial vehicles (MAVs) face limited flight times, which adversely impacts their efficacy for scenarios such as first response and disaster recovery, where it might be useful to deploy persistent radio relays and quadrotors for monitoring or sampling. Thus, it is important to enable micro-aerial vehicles to land and perch on different surfaces to save energy by cutting power to motors. We are motivated to use a downward-facing gripper for perching, as opposed to a side-mounted gripper, since it could also be used to carry payloads. In this paper, we predict and verify the performance of a custom gripper designed for perching on smooth surfaces. We also present control and planning algorithms, enabling an underactuated quadrotor with a downward-facing gripper to perch on inclined surfaces while satisfying constraints on actuation and sensing. Experimental results demonstrate the proposed techniques through successful perching on a glass surface at various inclinations, including...
This paper presents design principles for compliant mechanisms used to support and load spines us... more This paper presents design principles for compliant mechanisms used to support and load spines used in climbing rough vertical surfaces. The design principles ensure that constraints associated with spine/surface interactions are satisfied and that when multiple spines are placed in contact with a surface they share the load without premature failures or spine overloading. The design principles are demonstrated with a compliant mechanism that has been used for robotic and human climbing on surfaces such as brick, stucco and concrete.
Bioinspiration is an increasingly popular design paradigm, especially as robots venture out of th... more Bioinspiration is an increasingly popular design paradigm, especially as robots venture out of the laboratory and into the world. Animals are adept at coping with the variability that the world imposes. With advances in scientific tools for understanding biological structures in detail, we are increasingly able to identify design features that account for animals' robust performance. In parallel, advances in fabrication methods and materials are allowing us to engineer artificial structures with similar properties. The resulting robots become useful platforms for testing hypotheses about which principles are most important. Taking gecko-inspired climbing as an example, we show that the process of extracting principles from animals and adapting them to robots provides insights for both robotics and biology.
We present results of experiments with a haptic feedback device that imparts tangential deformati... more We present results of experiments with a haptic feedback device that imparts tangential deformations to the fingertips for displaying changes in force experienced by an MR-compatible optically-instrumented biopsy needle. The display is actuated using multiple layers of MR-compatible electroactive polymers stretched in a plastic frame. Users can use the device to sense events such as membrane puncture, as the needle is driven through a tissue phantom, with 98.9% reliability.
Soft robotic hands can facilitate human–robot interaction by allowing robots to grasp a wide rang... more Soft robotic hands can facilitate human–robot interaction by allowing robots to grasp a wide range of objects safely and gently. However, their performance has been hampered by a lack of suitable sensing systems. We present a flexible and stretchable multi-modal sensor network integrated with a soft robotic hand. The design of wired sensors on a flexible metalized film was embodied through a manufacturing approach that uses both UV laser metal ablation and plastic cutting simultaneously to create sensor electrode and stretchable conductive wires in a Kirigami pattern into a single network. We evaluated the interconnects and sensors by measuring an impedance change to each external stimulus and showed that are not substantially affected by stretching the network. With the sensor sheet wrapped around a soft robotic gripper, we demonstrated several interaction scenarios, including a warm burrito for food handling, and a warm baby doll for medical applications.
The International Journal of Robotics Research, 2018
This paper presents models of arrays of compliantly supported spines that attach to rough surface... more This paper presents models of arrays of compliantly supported spines that attach to rough surfaces. The applications include climbing and perching robots. Surfaces are characterized in terms of asperity distributions, which lead to stochastic models of spine force capabilities over a range of loading directions. Models cover unidirectional spine arrays and pairs of opposed arrays that withstand normal forces pulling away from a surface. Experiments on a variety of surfaces confirm the predicted behavior. For opposed spine arrays, the overall load capability also depends on the preloading strategy for applying internal forces. Insights from the analysis guide the design of spine array mechanisms to allow, for example, a small aerial platform to attach to walls and ceilings.
Micro-aerial vehicles (MAVs) face limited flight times, which adversely impacts their efficacy fo... more Micro-aerial vehicles (MAVs) face limited flight times, which adversely impacts their efficacy for scenarios such as first response and disaster recovery, where it might be useful to deploy persistent radio relays and quadrotors for monitoring or sampling. Thus, it is important to enable micro-aerial vehicles to land and perch on different surfaces to save energy by cutting power to motors. We are motivated to use a downward-facing gripper for perching, as opposed to a side-mounted gripper, since it could also be used to carry payloads. In this paper, we predict and verify the performance of a custom gripper designed for perching on smooth surfaces. We also present control and planning algorithms, enabling an underactuated quadrotor with a downward-facing gripper to perch on inclined surfaces while satisfying constraints on actuation and sensing. Experimental results demonstrate the proposed techniques through successful perching on a glass surface at various inclinations, including...
This paper presents design principles for compliant mechanisms used to support and load spines us... more This paper presents design principles for compliant mechanisms used to support and load spines used in climbing rough vertical surfaces. The design principles ensure that constraints associated with spine/surface interactions are satisfied and that when multiple spines are placed in contact with a surface they share the load without premature failures or spine overloading. The design principles are demonstrated with a compliant mechanism that has been used for robotic and human climbing on surfaces such as brick, stucco and concrete.
Bioinspiration is an increasingly popular design paradigm, especially as robots venture out of th... more Bioinspiration is an increasingly popular design paradigm, especially as robots venture out of the laboratory and into the world. Animals are adept at coping with the variability that the world imposes. With advances in scientific tools for understanding biological structures in detail, we are increasingly able to identify design features that account for animals' robust performance. In parallel, advances in fabrication methods and materials are allowing us to engineer artificial structures with similar properties. The resulting robots become useful platforms for testing hypotheses about which principles are most important. Taking gecko-inspired climbing as an example, we show that the process of extracting principles from animals and adapting them to robots provides insights for both robotics and biology.
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