Insects are a constant source of inspiration for roboticists. Their compliant bodies allow them to squeeze through small openings and be highly resilient to impacts. However, making subgram autonomous soft robots untethered and capable of responding intelligently to the environment is a long-standing challenge. One obstacle is the low power density of soft actuators, leading to small robots unable to carry their sense and control electronics and a power supply. Dielectric elastomer actuators (DEAs), a class of electrostatic electroactive polymers, allow for kilohertz operation with high power density but require typically several kilovolts to reach full strain. The mass of kilovolt supplies has limited DEA robot speed and performance. In this work, we report low-voltage stacked DEAs (LVSDEAs) with an operating voltage below 450 volts and used them to propel an insect-sized (40 millimeters long) soft untethered and autonomous legged robot. The DEAnsect body, with three LVSDEAs to drive its three legs, weighs 190 milligrams and can carry a 950-milligram payload (five times its body weight). The unloaded DEAnsect moves at 30 millimeters/second and is very robust by virtue of its compliance. The sub–500-volt operation voltage enabled us to develop 780-milligram drive electronics, including optical sensors, a microcontroller, and a battery, for two channels to output 450 volts with frequencies up to 1 kilohertz. By integrating this flexible printed circuit board with the DEAnsect, we developed a subgram robot capable of autonomous navigation, independently following printed paths. This work paves the way for new generations of resilient soft and fast untethered robots.

Head-mounted displays for virtual reality (VR) and augmented reality (AR) allow users to see highly realistic virtual worlds. The wearable haptics that enable feeling and touching these virtual objects are typically bulky, tethered, and provide only low fidelity feedback. A particularly challenging type of wearable human-machine interface is feel-through haptics: ultra-thin wearables so soft as to be mechanically imperceptible when turned off, yet generating sufficient force when actuated to make virtual objects feel tangible, or to change the perceived texture of a physical object. Here, 18 µm thick soft dielectric elastomer actuators (DEA), directly applied on the skin, reports rich vibrotactile feedback generation from 1 Hz to 500 Hz. Users correctly identifies different frequency and sequence patterns with success rates from 73 to 97% for devices applied on their fingertips. An untethered version weighing only 1.3 grams allowed blindfolded users to correctly identify letters by "seeing" them through their fingers. The silicone-based DEA membrane is mechanically transparent, enabling wearable haptics for the many applications where hand dexterity is critical. The feel-through DEA can be placed in array format anywhere on the body.

Abstract-This paper presents a very-high-speed (VHS) slotless permanent-magnet motor design procedure using an analytical model. The model is used to design the optimal prototype (target: 200 kr/min, 2 kW). The multiphysics analytical model allows a quick optimization process. The presented model includes the magnetic fields, the mechanical stresses in the rotor, the electromagnetic power losses, the windage power losses, and the power losses in the bearings. VHS machines need a new torque measurement method. This paper presents the developed method. It also presents a ball bearing friction torque measurement method designed particularly for VHS machines. Remarkably, the method allowed us to design a prototype which operates beyond the target of speed and power. The results given by the model are compared with the measurements of the prototype.

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Abstract-We are developing haptic interfaces compatible with functional Magnetic Resonance Imaging (fMRI) for neuroscience studies. The presented prototype with one rotary degree of freedom is actuated by a traveling wave ultrasonic motor operating under admittance control. Torque is sensed from the deflection of an elastic polymer probe via light intensity measurement over optical fibers. This concept allows us to place all electronic components outside the shielded MR room. Hence, the device can be used in conjunction with fMRI, providing torque and motion feedback simultaneously with imaging. Its compactness and simplicity facilitate the construction of multiple degree of freedom systems.