Springtails are tiny arthropods that crawl and jump. They jump by temporarily storing elastic energy in resilin elastic cuticular structures and releasing that energy to accelerate a tail, called a furca, propelling them in the air. This paper presents an autonomous, springtail-inspired microrobot that can crawl and jump. The microrobot has a mass of 980mg and stands 13mm tall, and has on-board sensing, computation, and power, enabling autonomy. The microrobot was designed with a super-elastic shape memory alloy (SMA) spring that is manually loaded to store elastic energy. The on-board sensing and computation triggers an actuator at the jump frequency range that unlatches the spring, launching the microrobot into the air at speeds up to 3.171ms−1. At the same time, the microrobot is capable of crawling, when actuated at frequencies lower or higher than the jump frequency range, demonstrating autonomous multi-modal locomotion. This work opens up new pathways toward autonomy in multi-modal microrobots.

This work demonstrates 3D printed soft actuators with complex shapes and remote actuation using an external magnetic field. Instead of embedding magnetic particles in a polymeric matrix, we fabricated a novel ferrofluid-based actuator, in which the fluid can be moved to different locations in the actuator to affect actuator response. We studied the effect of both the ferrofluid and the 3D printed material on the motion of simple actuators using 3D printed tubes. In addition, we 3D printed more complex actuators mimicking a human hand and a worm to demonstrate more complex motion.

Sensors to measure quadcopter ground effect are often relatively large, heavy, and require significant power, which restricts their applicability when it comes to small quadcopters and other aircraft that require lightweight and non-obstructive solutions. This paper presents the design of an elastomeric contact-resistance-based airflow sensor to measure ground effect with a mass of approximately 0.04 g and a power draw of 42 μW when in operation. It uses a rigid flap attached to the top of a flexible conductive pillar (CNT/PDMS), which deflects with varying winds speeds. A simple model is presented to describe expected trends between air flow speeds and sensor deflection and is compared with a wind tunnel characterization of the sensor for varying airflows. The sensor is characterized in a wind tunnel to identify a minimum airflow necessary for sensor functionality. Finally, sensors are attached to a Crazyflie 2.0 (Bitcraze) quadcopter and tested for performance in detecting ground effect, where there is a clear trend between sensor output and the intensity of the turbulent flow, related to proximity to ground and thrust level.

This paper describes an intuitive method for the design and fabrication of small-scale robots with multi-material compliant mechanisms in 3D. The rigid components are 3D printed, and flexures are inserted into the rigid components, creating the final mechanism. The assembled mechanisms are robust, requiring over 1 N of force to delaminate, and surviving 150,000 cycles of bending without failure. A 6 g walking quadrupedal millirobot is presented as a case study for the design and manufacturing methodology. The quadrupedal millirobot has been demonstrated moving at top speeds of 9 mm/s (0.3 body lengths/s).