Magnetic\nMicroactuators Based on Particle Jamming

Magnetic microactuators and microrobots have the potential\nto revolutionize\nremote manipulation and swarm-based collaboration. Unfortunately,\nconventional approaches to controlling individual magnetic systems\ncannot be scaled down to the microscale due to fundamental challenges\nin the generation and modification of magnetic fields. We here demonstrate\na novel actuation mechanism that imparts magnetic microactuators with\nan unprecedented ease of fabrication and dimensional scalability.\nThrough mechanical jamming in binary particle mixtures, magnetic ordering,\nand pronounced anisotropy could be induced. Combined simulation and\nexperimental investigation confirm the importance of arresting forces\nfrom neighboring particles as the origin of this behavior. This sensitivity\nof magnetic properties to assembly morphology can be exploited to\nproduce novel actuators that utilize minute changes in particle size\nor pressure. We demonstrate the transduction of particle swelling\ninto magnetic torque locking that enables active magnetic control\nin microrobots for future remote operating applications.