This paper describes the design and evaluation of a Legged Piezoelectric Miniature Robot (LPMR) propelled by standing wave vibrations at the legs, which are biologically inspired by the bounding gait locomotion of animals. The LPMR comprises of a single piezoelectric patch, a metal beam, two contact joints, two rigid legs and is able to achieve tether-less remote controlled operation. Through analysis of the bending modes of vibrations and driving frequency, a forward and backward motion of the underactuated system is achieved by choosing specific positions for the legs. At 100 V amplitude, the LPMR with the weight of 6.27 g, length of 50 mm, width of 10 mm and height of 1.5 mm achieves a maximum linear speed of 246.5 mm/s for forward motion and 302 mm/s for backward motion. The LPMR is also able to carry a payload of 100 g at a speed of 49.6 mm/s for forward motion and 87.9 mm/s for backward motion when applying 100 V amplitude. The corresponding maximum force generated by the LPMR is 9.8 mN during forward motion and 12 mN during backward motion at the same applied voltage. An experimental characterization for the LPMR in terms of speed versus applied voltage, speed versus embedded mass and blocking force for different applied voltages is explored and evaluated in this study.

Automated welding has been very effective in enhancing the quality and quantity of weld jobs along with improving the safety of the workers. Nevertheless, most existing welding robots are massive and immobile. Typically, the work-pieces are transferred to the robots for welding. This makes it difficult for many welding applications that have large scale structures e.g. shipbuilding, construction, on-site repair work, etc. In these cases, the welding robot should be able to be transported to the work-pieces. The purpose of this paper is to explore and study various recent developments in portable welding robot designs. Based on this, several strategies of designing portable welding robot are classified and discussed.

In this paper, a miniature nonholonomic spherical rolling robot capable of navigating over two dimensional surfaces is described. This 55 gram spherical robot consists of a 6 cm diameter external spherical shell driven by an internal two-wheeled differential drive cart. A gravity powered pendulum effect is produced as the internal device climbs up the internal surface of the shell, propelling the robot forward up to a speed of 0.16m/s. We derived its dynamic model using Lagrangian, and studied its dynamics and performance under various applied torques. The spherical robot is built and its overall mechanical, hardware and control architecture are elaborated. Experiments are conducted to evaluate the robot open and closed loop performance on a linear trajectory, captured using an optical motion capture system. We showed that with our implemented PD controller, the robot can follow the desired orientation.