# A Jumping Robot Driven by a Dielectric Elastomer Actuator
## 3 Prototype Implementation and Experiment
### Performance of the Jumping Robot  
The overall prototype of the jumping robot is shown in Figure 11. The robot consisted of a DEA, transmission structure, and spring-loaded leg, and the support structure was made by 3D printing. The overall size of the robot was 200 mm\(\star\)140 mm\(\star\)300 mm, and the total mass was 530 g.  
Figure 10: (**a**) The output forces of the 1-layer, 10-layer, 15-layer, and 20-layer DEAs at 4–7 kV. (**b**) The displacement of the 20-layer DEA at 4–7 kV.  
The jumping control of the jumping robot is mainly composed of two parts. The first is a power supply device for applying voltage to the DEA, which is mainly composed of a small high-voltage power supply (EMCO), an SCM (Single-Chip Microcomputer), and a 7 kV high-voltage relay. The second is the helm gear used to unlock the locking rod on the locking turntable. The control process of jumping is shown in Figure 12. During the take-off preparation phase of the robot, the DEA is supplied with a square wave voltage of 0.4 Hz by the power supply device. When the spring energy is stored, the helm gear connected to the locking rod is rotated 90\({}^{\circ}\) to accomplish the unlocking, and the turntable is unlocked to realize the jumping of robot.  
During the energy storage phase of the robot, the DEA is supplied with a square wave voltage (6.5 kV, 0.4 Hz) to drive the energy storage of the spring leg. A high-speed camera was used to record the energy storage process of the robot. The recording results are shown in Figure 13. Also, the compression displacement of the spring leg in each cycle of energy storage was measured with a laser displacement sensor. The measurement results are shown in Figure 14. The robot completed 25 cycles of energy storage in 60 s and compressed the spring leg by 22.26 mm. It can be seen that during the first 12 energy storage cycles, the compression displacement of the spring leg in each cycle was large as the driving force provided by the DEA was much larger than the reaction force of the spring leg, and the average compression displacement reached 1.25 mm. With continuous compression of the spring leg, the reaction force of the spring leg becomes larger. In the next 13 energy storage cycles, the compression displacement of the spring leg in each cycle was significantly reduced, and the average compression displacement was only 0.605 mm. Finally, the driving force and the reaction force of the spring leg reached equilibrium, and the spring leg was no longer compressed. We observed an unexpected displacement reduction between two cycles of energy storage (Figure 14), which should be owing to the unstable structure of the robot caused by low-quality 3D printing and certain assembly errors.  
Figure 11: The overall prototype of the jumping robot.  
Figure 12: The jumping control of the jumping robot.  
When the robot is preparing to jump, the SCM is applied to control the helm gear to unlock the locking rod. A high-speed camera was applied to record the jumping process of the jumping robot, as shown in Figure 15. The energy storage and jumping process of robot is shown in Supplementary Materials. It can be seen that the jumping pose of the robot was very similar to the dual-mass SLIP model. The robot reached a maximum jumping height of 45 mm in 0.29 s, and the time from jumping to landing was 0.45 s after unlocking.