A steerable miniature legged robot based on piezoelectric bending actuators

Micro robots, due to their light weight, small size and high mobility, can explore narrow space or hazardous locations that humans or larger robots cannot reach. Consequently, both academia and industry are concerned with the development of advanced microrobots. In this paper, we design a steerable miniature legged robot (SMLR) which possesses light weight and controllable linear/steerable motion by using two piezoelectric bending actuators. Its dimensions are 35 mm × 30 mm × 9 mm (length × width × height) and mass is 9 g. User can modulate the speed, turning radius, and load capacity of the robot by simply tuning the driving voltage. The robot exhibits a speed of 330 mm s^-1 and a turning radius of 102 mm upon a driving voltage of 200 V and a frequency of 8.67 kHz. Moreover, it is capable of driving a 55 g embedded mass at a speed of 20 mm s^-1 under a voltage of 200 V, and its simple design is ideal for down-sizing. Further, we establish a series of open-loop control programs in a virtual instrument through LabVIEW to accurately control the behavior of the SMLR (the location error is less than 5 mm), demonstrating its great potential in practical applications such as movement in a narrow space.