8 research outputs found
Rapid manufacturing of color-based hemispherical soft tactile fingertips
Tactile sensing can provide access to information about the contact (i.e.
slippage, surface feature, friction), which is out of reach of vision but
crucial for manipulation. To access this information, a dense measurement of
the deformation of soft fingertips is necessary. Recently, tactile sensors that
rely on a camera looking at a deformable membrane have demonstrated that a
dense measurement of the contact is possible. However, their manufacturing can
be time-consuming and labor-intensive. Here, we show a new design method that
uses multi-color additive manufacturing and silicone casting to efficiently
manufacture soft marker-based tactile sensors that are able to capture with
high-resolution the three-dimensional deformation field at the interface. Each
marker is composed of two superimposed color filters. The subtractive color
mixing encodes the normal deformation of the membrane, and the lateral
deformation is found by centroid detection. With this manufacturing method, we
can reach a density of 400 markers on a 21 mm radius hemisphere, allowing for
regular and dense measurement of the deformation. We calibrated and validated
the approach by finding the curvature of objects with a threefold increase in
accuracy as compared to previous implementations. The results demonstrate a
simple yet effective approach to manufacturing artificial fingertips for
capturing a rich image of the tactile interaction at the location of contact
3D-printed biomimetic artificial muscles using soft actuators that contract and elongate
Biomimetic machines able to integrate with natural and social environments will find ubiquitous applications, from biodiversity conservation to elderly daily care. Although artificial actuators have reached the contraction performances of muscles, the versatility and grace of the movements realized by the complex arrangements of muscles remain largely unmatched. Here, we present a class of pneumatic artificial muscles, named GeometRy-based Actuators that Contract and Elongate (GRACE). The GRACEs consist of a single-material pleated membrane and do not need any strain-limiting elements. They can contract and extend by design, as described by a mathematical model, and can be realized at different dimensional scales and with different materials and mechanical performances, enabling a wide range of lifelike movements. The GRACEs can be fabricated through low-cost additive manufacturing and even built directly within functional devices, such as a pneumatic artificial hand that is fully three-dimensionally printed in one step. This makes the prototyping and fabrication of pneumatic artificial muscle-based devices faster and more straightforward
Development of a Soft Robotics Module for Active Control of Sitting Comfort
Sitting comfort is an important factor for passengers in selecting cars, airlines, etc. This paper proposes a soft robotic module that can be integrated into the seat cushion to provide better comfort experiences to passengers. Building on rapid manufacturing technologies and a data-driven approach, the module can be controlled to sense the applied force and the displacement of the top surface and actuate according to four designed modes. A total of 2 modules were prototyped and integrated into a seat cushion, and 16 subjects were invited to test the module’s effectiveness. Experiments proved the principle by showing significant differences regarding (dis)comfort. It was concluded that the proposed soft robotics module could provide passengers with better comfort experiences by adjusting the pressure distribution of the seat as well as introducing a variation of postures relevant for prolonged sitting
Kinematics of soft robots by geometric computing
Robots fabricated with soft materials can provide higher flexibility and, thus, better safety while interacting in unpredictable situations. However, the usage of soft material makes it challenging to predict the deformation of a continuum body under actuation and, therefore, brings difficulty to the kinematic control of its movement. In this article, we present a geometry-based framework for computing the deformation of soft robots within the range of linear material elasticity. After formulating both manipulators and actuators as geometry elements, deformation can be efficiently computed by solving a constrained optimization problem. Because of its efficiency, forward and inverse kinematics for soft manipulators can be solved by an iterative algorithm with a low computational cost. Meanwhile, components with multiple materials can also be geometrically modeled in our framework with the help of a simple calibration. Numerical and physical experimental tests are conducted on soft manipulators driven by different actuators with large deformation to demonstrate the performance of our approach