Underwater control applications, such as control of Autonomous Underwater Vehicles (AUV)s, have recently gained significant interest, and there is a growing demand for high-speed wireless communication between AUVs and base station. Acoustic communication provides low data rates and high propagation delays, both of which are not suitable for employing high control gains for the navigation of AUVs. On the other hand, Radio Frequency (RF) communication provides high data rate, but it is constrained by high attenuation due to high conductivity and permittivity of water resulting in a short working range. In this work, we propose an underwater networked control system with acoustic and RF hybrid communication, where an acoustic link is employed for long range communication and RF link is applied in close range. Our performance results indicate that the acoustic and RF hybrid communication system takes up to 38.5% less time to dock, up to 91% smaller steady state error and spends up to 39% lower communication energy as compared to the acoustic only system at the expense of up to 22.35% higher motive energy.

Networked control systems offer significant advantages in terms of reliability, commissioning and maintenance, especially for complex systems. They must be able to withstand delays and data corruption caused by the underlying communication network. Existing results in networked control systems provide varying degrees of robustness. However, cost is also an important factor for real world implementations, which further restricts the bandwidth of the underlying network and complexity of the communication protocol. In this paper we introduce a networked control system method, WMBPNCS, that we have previously proposed, and implement a control system using IEEE 802.15.4 (ZigBee) as its communication protocol, in an attempt to overcome these problems. We find through simulations that performance of our implementation is acceptable even under large amounts of random network delay and data loss.

Accessing volumetric medical data requires advanced visualization techniques. One approach is to show slices in situ, by projecting images into space at the proper position. We propose using floating images, that is, undistorted real images of displays, appearing at the desired position and orientation. Such floating images are made possible by the new optical device eDCRA' invented at NICT in Japan. To enhance the freedom of the user, we have developed a robot-assisted interactive visualization system, where the user can ehold' the image slice in her/his hand, and freely change its position and orientation, thus inspect any part of the volumetric data set as desired. The hand position is detected by a stereo camera and image processing. We describe the structure and operation of our system, and show samples of its usage.

Owing to their distributed architecture, networked control systems (NCSs) are proven to be feasible in scenarios where a spatially distributed feedback control system is required. Traditionally, such NCSs operate over real-time wired networks. Recently, in order to achieve the utmost flexibility, scalability, ease of deployment, and maintainability, wireless networks such as IEEE 802.11 wireless local area networks (LANs) are being preferred over dedicated wired networks. However, conventional NCSs with event-triggered controllers and actuators cannot operate over such general purpose wireless networks since the stability of the system is compromised due to unbounded delays and unpredictable packet losses that are typical in the wireless medium. Approaching the wireless networked control problem from two perspectives, this work introduces a practical wireless NCS and an implementation of a cooperative medium access control protocol that work jointly to achieve decent control under severe impairments, such as unbounded delay, bursts of packet loss and ambient wireless traffic. The proposed system is evaluated on a dedicated test platform under numerous scenarios and significant performance gains are observed, making cooperative communications a strong candidate for improving the reliability of industrial wireless networks.

SURALP is a new walking humanoid robot platform designed at Sabanci University - Turkey. The kinematic arrangement of the robot consists of 29 independently driven axes, including legs, arms, waist and a neck. This paper presents the highlights of the design of this robot and experimental walking results. Mechanical design, actuation mechanisms, sensors, the control hardware and algorithms are introduced. The actuation is based on DC motors, belt and pulley systems and Harmonic Drive reduction gears. The sensory equipment consists of joint encoders, force/torque sensors, inertial measurement systems and cameras. The control hardware is based on a dSpace digital signal processor. A smooth walking trajectory is generated. A variety of controllers for landing impact reduction, body inclination and Zero Moment Point (ZMP) regulation, early landing trajectory modification, and foot-ground orientation compliance and independent joint position controllers are employed. A posture zeroing procedure is followed after manual zeroing of the robot joints. The experimental results indicate that the control algorithms presented are successful in improving the stability of the walk.

The authors have proposed a control system of a quadruped locomotion robot by using nonlinear oscillators. It is composed of a leg motion controller and a gait pattern controller. The leg motion controller drives the actuators of the legs by using local feedback control. The gait pattern controller involves nonlinear oscillators with mutual interactions. In the paper, capability of adaptation of the proposed control system to variance of the environment is verified through numerical simulations and hardware experiments. With the input signals from the touch sensors at the tips of the legs, the nonlinear oscillators tune the phase differences among them through mutual entertainments. As a result, a gait pattern corresponding to the states of the system or to the properties of the environment emerges. The robot changes its gait pattern adaptively to variance of the environment and establishes a stable locomotion while suppressing the energy consumption.