An Electromagnetic Soft Robot that Carries its Own Magnet

Versatile Ultrasoft Electromagnetic Actuators with Integrated Strain‐Sensing Cellulose Nanofibril Foams

“…The core comprises a soft, conducting strain‐sensing foam, and the whole device is encapsulated with an outer soft, insulating CNF foam. There are previous reports on single‐coil actuators; [ 17–20,23,25,26,28 ] however, such designs exhibit a fast decrease in force with increasing coil distance from the magnet, resulting in a short effective stroke length (Figure 1d). We hypothesized that by increasing the number of coils, the effective stroke length could be increased.…”

“…[5] Actuation is one of the most challenging aspects of soft robotics, and a variety of approaches have been explored, including pressure-driven actuation, [6,7] thermal actuation, [8,9] humiditydriven actuation, [10][11][12][13] dielectric elastomer actuation, [14][15][16] and electromagnetic actuation. [17][18][19][20][21][22][23][24][25][26][27][28] Pressure-driven actuators can generate large forces and deformations but have slow response and require relatively high-pressure equipment to function. [6,7] Thermal actuators can generate large deformations and forces, but are hard to control, slow in response time, and require relatively high temperatures.…”

“…Soft actuators based on intrinsically stretchable conductors are especially dependent on strong external magnetic fields due to their relatively low conductivity, which restricts the number of feasible applications considerably. [17][18][19][20]23] While there are some reports on internal magnets for improving the force of soft electromagnetic actuators, [18,[25][26][27][28] the proposed structures consist of one or two coils, thereby limiting the stroke length. The generated force in such actuators depends both on the actuator deformation and on the excitation current, which makes them difficult to control.…”

Locally Addressable Energy Efficient Actuation of Magnetic Soft Actuator Array Systems

“…A comparison between the presented MSMs (lifting and radial linear motion) and other types of artificial muscles and near‐field magnetic actuators is shown in Table S1 (Supporting Information). [ 44 , 64 , 65 , 74 , 75 , 76 , 77 , 78 ]…”

“…Alternatively, electromagnetic near‐field sources generate time‐varying fields. For example, copper solenoid arrays control planar motion of ferrofluidic robots, [ 63 ] liquid metal‐based solenoids exert linear forces on a permanent magnetic core for biomimicry [ 64 ] and push and pull permanent magnets as part of a soft gripper. [ 65 ] Also, printed circuit board‐based coil arrays control diamagnetically levitating permanent magnets, [ 66 , 67 ] , direct sliding motion of disk‐shaped permanent magnets [ 68 , 69 , 70 , 71 ] , and control the position of superparamagnetic nanoparticles.…”