Hybrid Actuation Approach

   Most commercial robots today are deployed in restricted environments where close physical interaction between humans and robots is strictly regulated. However, with ongoing technological advances, there is a strong demand for robots that can be operated in close proximity to humans. In order to satisfy such demand, it is crucial to take people's safety into consideration as robots could cause fatal injuries to people when unpredictable collisions occur. Thus, it is of utmost importance to design a safe human-friendly robot without limiting its performance. In order to heighten the performance, most robots today use low power density electrical motors with high gear ratios to produce high torque and acceleration. As a trade-off, these performance-based robots have high mechanical impedance, and low backdrivability, which results in inherently less safe robots.

   The focus of hybrid actuation is to design a human-friendly robot by overcoming the limitation of the trade-off between safety and performance. In order to do so, a newly investigated hybrid (macro-mini) actuation technique (using a combination of pneumatic artificial muscles (PAM) and electric motors) is introduced. This new actuation technique shows significant performance improvement over robots that solely use PAM, and at the same time, have lower impedance than the performance-based robots using electrical motors with a high gear ratio. Thus, this technique ensures the safety of people in a human-robot interactive environment while showing reliable performance.

Self-Powered Bio-Friendly Tactile Sensor

   With the growing numbers of industrialized countries, tactile sensors act as a key role to collect big data for communication, automated control, malfunction detection, etc. Although numerous sensors (e.g., microfluidic, capacitive, strain gauge, etc.) have been adopted to industrial sites, they cannot function without external power. Thus, a self-powered triboelectric sensor with high charge density has been proposed to eliminate the need for external power. To meet the requirements in the various sites, we have utilized a deformable foam layer with different stiffness to adjust the dynamic range of the sensors without a complex fabrication process. Furthermore, the proposed tactile sensor is able to harvest ambient energy from the environment when not in use as a tactile sensor, owing to its energy harvesting properties.