The compliant, continuum, and configurable robotics field in general has gained growing interest in the past years especially with the exciting advances in artificial intelligence technology, [1] which could enable various valuable applications ranging from manufacturing to safety and healthcare. [2,3] Soft robots are of notable interest because, unlike their rigid counterpart, they can easily deform while being mechanically resilient, [4,5] adapt to the outer environment without harm to humans, [6] and finally, enable low-cost manufacturing. [7] For robots to interact with the outer environment and complete tasks, a set of sensors and actuators need to be integrated into the system. Soft robots, in specific, present additional challenges because their sensing and actuation devices are generally highly integrated within the body of the robot and its whole functionality. These challenges become even more critical when the soft robot is scaled down to sub-centimeter size as the sensing, power, and data analysis units are moved off-board. As a result, miniaturized soft actuators that respond to various stimuli and show large deformations in addition to mechanical resilience are crucial. These would be particularly promising for application in artificial muscles, microrobots, and micro-manipulators. [8-10] Active and soft materials are promising for this task as they can be actuated through various external stimuli, such as photons, thermal, magnetic and/or electric field. Such materials range from particles, to polymers (either electroactive or shape memory), papers, fluids, shape memory alloys (SMAs), liquid metals, hydrogels, 2D materials, or a combination of these. [6-25] Nevertheless, some materials can be more suitable for a specific set of applications than others; for instance, materials stimulated by the near-infrared (NIR) spectrum are promising for biomedical applications, whereas sunlight-stimulated materials are suitable for nature-inspired soft robots used in outside environments. Various useful metrics are generally used to assess the performance of the actuators; these include the generated stress and strain, Young's modulus or measured stiffness, in addition to their power, work, energy, and force density. In this Review article, however, we focus on the application of the soft actuators in soft robotics where the reported metrics include mode and speed of actuation (or locomotion), power, voltage, current (of the driving signal), lifting force, and weight among others. In this Review article, different active materials that have been developed and used in soft actuators for soft robotics are discussed and grouped by the stimulus that generates the actuation response as shown in Figure 1. The physics of operation, resulting deformations, mechanical resilience, and their pros and cons are presented with a focus on the applications of the different soft

For decades, the revolution in design and fabrication methodology of flexible capacitive pressure sensors using various inorganic/organic materials has significantly enhanced the field of flexible and wearable electronics with a wide range of applications in aerospace, automobiles, marine environment, robotics, healthcare, and consumer/portable electronics. Mathematical modelling, finite element simulations, and unique fabrication strategies are utilized to fabricate diverse shapes of diaphragms, shells, and cantilevers which function in normal, touch, or double touch modes, operation principles inspired from microelectromechanical systems (MEMS) based capacitive pressure sensing techniques. The capacitive pressure sensing technique detects changes in capacitance due to the deformation/deflection of a pressure sensitive mechanical element that alters the separation gap of the capacitor. Due to advancement in state‐of‐the‐art fabrication technologies, the performance and properties of capacitive pressure sensors are enhanced. In this review paper, recent progress in flexible capacitive pressure sensing techniques in terms of design, materials, and fabrication strategies is reported. The mechanics and fabrication steps of paper‐based low‐cost MEMS/flexible devices are also broadly reported. Lastly, the applications of flexible capacitive pressure sensors, challenges, and future perspectives are discussed.

Soft Robotics In article number http://doi.wiley.com/10.1002/aisy.202000128, Muhammad Mustafa Hussain and co‐workers present a comprehensive review on soft robots which are paving the way towards a wide range of vital applications such as drug delivery, among others. Various state‐of‐the‐art soft actuators which respond to different stimuli, including light, heat, and applied electric field with a focus on their various applications in soft robotics, are discussed.

In article number 2001023, Muhammad M. Hussain and co‐workers provide a comprehensive review on flexible capacitive‐based pressure sensors with a focus on their design approaches and state‐of‐the‐art fabrication techniques. In addition, their various demonstrated applications over the last few years are reported and discussed, including but not limited to, aerospace, automobile, marine, robotics, wearables, and healthcare fields.

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This paper presents the mathematical modeling based design and simulation of normal mode MEMS capacitive pressure sensor for blood pressure sensing application. The typical range of blood pressure is 80 -120 mm Hg. But this range varies in case of any stress, hypertension and some other health issues. Analytical simulation is implemented using MATLAB ® . Basically, normal mode capacitive pressure sensors have a fixed backplate and a moveable diaphragm which deflects on application of pressure with the condition that it must not touch the backplate. Deflection depends on material as well as thickness, shape and size of diaphragm which can be of circular, elliptical, square or rectangular shape. In this paper, circular shape is chosen due to higher sensitivity compared to other diaphragm shapes. Deflection, base capacitance, change in capacitance after applying pressure and sensitivity is reported for systolic and diastolic blood pressure monitoring application and study involves determining the optimized design for the sensor. Diaphragm deflection shows linear variation with applied pressure, which follows Hook's Law. The variation in capacitance is logarithmic function of applied pressure, which is utilized for analytical simulation.

We present detailed shape-based analyses to compare the performance of metal foil-based capacitive pressure sensors based on the shape of the diaphragm (top electrode). We perform a detailed analysis on the use of new material and deflection in various shaped diaphragms to act as a performance indicator for pressure-based capacitive sensors. A low-cost, recyclable, and readily available material is used to present an alternative to the expensive materials used in conventional pressure sensors. Diaphragms of five different shapes (circle, ellipse, pentagon, square, and rectangle) are fabricated and analyzed. Mathematical, FEM, and experimental tests are performed for capacitive sensors fabricated in five different shapes. The mathematically calculated deflection for each shaped diaphragm is compared with the results of the corresponding FEM simulations. Two different experiments are performed to verify the performance of pressure sensors.

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