A tripodal wheeled mobile robot driven by a liquid metal motor

As a novel driving concept, the liquid metal motor (LMM) has been regarded as a promising actuator due to its unique traits, such as infinitely variable speed, lack of transmission chain, convenient maintenance, and silence. However, at present, driving devices based on this material are still in the preliminary and rudimentary stage, and representative application examples are scarce. Therefore, an 8-shaped tripodal wheeled mobile robot (WMR) completely driven by a LMM is designed in this study to further prove the practicability of this material. Through combining the Marangoni surface flow on a liquid metal droplet (LMD) caused by an electrochemical reaction and the eccentric torque generated by the change in droplet shape and position, the two independently driven wheels of the mobile robot are actuated at differential moving speeds. Additionally, a matching control module, a cell phone application, and a battery have been developed and added for wireless control of three types of driving functions (moving forward, steering, and stopping). It is expected that this work could further advance the development and application of LMMs and bring new ideas to the design of WMRs.