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User identification is an essential problem for security protection and data privacy preservation of wearable devices. With proper user identification, wearable devices can adopt personalized settings for different users, automatically label the corresponding data to protect user privacy, and help prevent illegal user spoofing attacks. Current user identification solutions proposed for wearable devices...
This paper proposes a novel control architecture for bilateral teleoperation with time delay. The proposed bilateral teleoperation system has transparency under the presence of time delay. The conventional bilateral teleoperation system cannot have transparency under time delay because the control goals are not clear and inappropriate in the presence of time delay. The proposed method utilizes the...
Power supply is an important inhibiting factor of autonomous operation of small ocean vehicles, wave energy vibration harvest method is a viable solution. The usual vibration energy harvest device is excited by its housing frame driven by external oscillation, subject to limited vehicle geometry size, and the low frequency of ocean waves, electrical power generated is very limited. A concept vehicle...
The aim of this study is to conduct a hydrodynamic analysis of a point absorber-type floating hemisphere with Power take-off(PTO) system for an optimum design of wave energy converter(WEC). In general, to predict the behavior of WEC, the equation of floating body motion can be solved in the frequency-domain analysis. A numerical model of PTO system is usually expressed as a linear damper-spring type...
A novel anchor system which can convert fluid energy into power is designed conceptually in this paper. It combines vortex induced vibration (VIV) and piezoelectric cantilever beam. The transversed motion model of the bluff body established with Sarplaya's lift decomposition model and the bending model of cantilever beam is established with Euler-Bernoulli assumption. With the two separate model the...
Point-absorbing converters are widely applied in exploiting of the wave energy. This paper will present some results of point absorber converters by experiment measurements in regular waves. Meanwhile, the research investigates the influence of take-off damping on the power output of wave energy converter. Results demonstrate the wave energy output of three-degree wave energy device is better than...
An investigation is conducted into the performance of passive, semi-active and active electromagnetic dampers. Theoretical models are constructed of the dampers and these are included in two degree of freedom models of the suspension. The passive and semi-active electromagnetic dampers are significantly heavier than commercial hydraulic dampers. In the case of active electromagnetic damper, the reduction...
This work provides a comparison of eight different hydrodynamic damping models for streamlined tail-controlled autonomous underwater vehicles (AUVs). We use an off-line least-squares method and an adaptive identifier method to approximate damping model coefficients and determine if one damping model is preferred over other models. We evaluate the two methods for estimating the parameters of the models...
This paper investigates wave-by-wave control of a single-mode wave energy converter driven to operate such that the oscillation velocity closely matches the hydrodynamically optimum velocity for best power absorption. Such control requires prediction of the wave profile using up-wave measurements. The goal of this research is to implement adaptive trajectory-tracking control using on-line estimation...
Parametric resonance of offshore crane cable was predicted by using Mathieu equation to provide structural safety prediction during subsea lowering operation. This paper studied the predicting method of offshore crane cable to complement the safety management during subsea lowering operation. The offshore crane cable was modeled as a tensioned long cylindrical structure and Mathieu instability coefficients...
The design of wave energy converter (WEC) is crucial in order to generate the optimum power required to safely and reliably benefit from the available wave energy resource to produce electricity. The effects of the added mass on the idealized power take-off wave energy absorber in irregular waves are examined using a linear frequency domain method. Two strategies in this study are to maximize the...
Mitsui Engineering and Shipbuilding (MES) was awarded for “Technical Development and Demonstration of Small, Efficient Wave-Power device” by Ministry of the Environment at fiscal year 2013 (October, 2013), and had been developing wave-power device aiming for a full-scale demonstration test at sea within fiscal year 2015. This lead to confirm its effect (the point absorber effect) at actual sea utilizing...
Although Lower Limb Robotic Rehabilitation device exhibit a great prospect in the rehabilitation of impaired limb, yet it has not been widely applied to clinical rehabilitation. This is mostly due to the insufficient bidirectional information interaction between exoskeleton and patient. In the shared control at the interaction point, it is very important that the deficiency of impaired lower limb...
In the presented paper an analytically force overshoots-free approach is described for the execution of robotics interaction tasks involving a compliant (of unknown geometrical and mechanical properties) environment. Based on the impedance control, the aim of the work is to perform force-tracking applications avoiding force overshoots that may result in task failures. The developed algorithm shapes...
Servo-controlled elevator is one of the primary flight control actuators which controls pitch of the aircraft. To prove out its design, a qualification test equipment or endurance test rig is needed. Using endurance test rig, aerodynamic load is simulated by a double-acting servo-controlled linear hydraulic cylinder to the elevator actuator. The design of the endurance test rig primarily depends on...
This paper presents an adaptive input shaping based on pole-zero cancellation (APZC) technique to suppress load sway of a crane system. In this method, a reference system is selected and the proposed adaptive shaper is made to force the actual system to adapt to the changes in natural frequency and damping ratio as the cable length increases or decreases. Simulation results are compared with a zero...
One of the major goal of human walking is controlling precise movement of the body i.e. to stay upright while advancing the step. On each foot, the ground reaction force (GRF) reflects that control. Typical walking involves a synchronized change in the pressure beneath the foot i.e. Center of Pressure (COP) according to the change in the knee angle. This study investigates the knee flexion characteristics...
We propose a two-layer control architecture for bilateral teleoperation with communication delays. The controller is structured with an (outer) performance layer and an (inner) passivity layer. In the performance layer, any traditional controller for bilateral teleoperation can be implemented. In the passivity layer, the output of the performance layer is modified to guarantee that, from the operator...
A concept for the fault-tolerant control of a primary flight control system featuring two parallel electromechanical actuators nominally operating in active-active mode is proposed. A detailed nonlinear model of the system under consideration is created to enable the design of high-level and low-level safety control functions. Three reaction sequences combining five different reactions are proposed...
This paper is concerned with the problem of the robust sampled-data H∞ control for an offshore steel jacket platform subject to the self-excited wave force and the external disturbance. First, by using the input delay method, the corresponding closed-loop system with the sampling measurements is transformed into a continuous-time system. Then, based on a Lyapunov functional, the H∞ performance is...
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