Advanced Robotics

Sakuma, Tomoki; Tsuda, Kenta; Umeda, Koudai; Sakaino, Sho; Tsuji, Toshiaki

doi: 10.1080/01691864.2017.1392343pmid: N/A

AbstractElectro-hydrostatic actuators (EHAs) possess excellent power/weight ratio and space-saving properties. However, uncertainty exists with respect to the presence of non-linear behaviors and dynamic characteristics. Servo pumps, hydraulic motors, and oil-filled pipes can be regarded as motors, loads, and springs, respectively. Hence, EHAs can be modeled as two-mass resonant systems. In this paper, we show a parameter identification method for modeling EHAs as two-mass resonant systems. Then, in order to suppress the effect of resonance, self-resonance cancellation technique is implemented. As a result, phase delay is significantly improved in the position tracking.

Damian, Dana D.; Fischer, Marco; Hernandez Arieta, Alexandro; Pfeifer, Rolf

doi: 10.1080/01691864.2017.1396250pmid: N/A

AbstractProsthetic hands introduce an artificial sensorimotor interface between the prosthesis wearer and the environment that is prone to perturbations. We analyze theoretically and evaluate psychophysically the performance in stable grip control in conditions of physical grasps perturbation, such as object slip. Simulation results suggest that user-centered stable grasp control depends on two primal user parameters: reaction time to slip and grip force intensity. Experiments with human users indicate that a user’s response time can be controlled by relaying information about the speed of the slipping object, while minimal grip force intensity can be adjusted with information about grip force at the onset of the slip. Based on our theoretical and experimental findings, we propose a stable grasp control method for prosthetic hands.

Zhong, Yong; Li, Zheng; Du, Ruxu

doi: 10.1080/01691864.2017.1392344pmid: N/A

AbstractThis paper presents a robot fish with a wire-driven caudal fin and a pair of pectoral fins. First, the design of the robot fish is presented. The caudal fin is driven through wire-driven mechanism. The pectoral fins can perform two degrees-of-freedom motions, i.e. flapping (roll) and feathering (pitch). The pectoral fins can move in labriform mode for propulsion, or for other purposes such as turning and diving. Second, the propulsion analysis models for caudal fin propulsion and pectoral fins propulsion are derived. Finally, three types of experiments are conducted. Experiment results show that the swimming speed of caudal fin propulsion and pectoral fin propulsion match the model predictions. Moreover, with the caudal fin propulsion alone, the robot fish can swim up to 0.66 BL/s (body length/second); with the pectoral fin propulsion alone, the robot fish can swim up to 0.26 BL/s. The pectoral fins can significantly improve the maneuverability of the robot fish. Without using the pectoral fins, the turning radius of the robot fish is 0.6 BL; with the pectoral fins, the turning radius is reduced to 0.25 BL.

Kakogawa, Atsushi; Ma, Shugen

doi: 10.1080/01691864.2017.1393348pmid: N/A

AbstractThis paper presents a multilink-articulated robot with omni and hemispherical wheels (AIRo-2.1) for inspecting and exploring pipelines. To quickly adapt to winding pipes, holonomic rolling movement without moving forward and backward is useful. However, this requires the rolling actuators to replace the driving actuators at the expense of the driving force. Furthermore, so far the number of driving wheels and torsion springs, magnitude of driving forces, stiffness and natural angle of the spring that are required to adapt to various pipelines have not been clarified. In this paper, we investigate the possibility of high maneuverability of multilink-articulated robots in winding pipes with as few driving actuators as possible and only elastic joints (torsion springs) for body bending. We further validate its effectiveness by experimental verification.