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It is known that new power transmission line inspection techniques have been developed over the last few years with great potential to improve and, in some cases, even replace traditional inspection procedures such as using helicopters and cars. A series of Unmanned Aerial Vehicles (UAVs) such as fixed-wing or rotary-wing UAVs, and vehicles that climb on the power transmission line, promise to revolutionize the inspection market. In this light, at least 39 new research studies and/or products have been conducted and/or introduced to the market, respectively. However, in an incipient way, some works point to the fusion of some technologies: the development of multi-rotor UAVs and the ability to connect and move over the power transmission line. In line with this, the current work was proposed, with significant unprecedented advances (such as an over-actuated control capacity with tilt rotors, the capability of a displacement in the angle, and the maintenance of active motors on the power transmission line), and the design, modeling, and control of an over-actuated UAV able to move over the conductor cable without the need for a new locomotion system is presented. The aircraft allows for a greater response and the indispensable ability to approximate landing in a power transmission line arbitrary position rather than the catenary lowest point (due to its ability to forward/backward move using the tilting rotors). Its design is detailed, its subsystems are described, and its normal and coupled flight mode dynamics are modeled. The results show good stability and reliable maneuvers for the coupling-to-power-transmission-line flight mode, without any overshoots, and the ability to follow the entire catenary through different Real Control Action (RCA) sets.

For the problem of robust fault tolerant control of over-actuated nonlinear systems, a new robust synthesis method is investigated. The nonlinear system is modeled via a T–S fuzzy system approach with actuators layout. Based on a designed non-parallel distributed compensation form controller, the closed loop system is obtained. Then a more generalized performance index is introduced by involving the system transients and actuator faults. With a newly proposed nonlinear approximation method, a series of linear matrix inequalities which can make the system robust stable are listed. Finally, based on a dynamic positioning vessel control task, the validity of the proposed method is verified. [ABSTRACT FROM AUTHOR]

This paper presented a novel adaptive cascade nonlinear trajectory tracking control scheme of over-actuated autonomous electric vehicles involving input saturation. First, a nonlinear vehicle dynamic model with input saturation is established, which can accurately describe the features of uncertainties and coupling of autonomous electric vehicles, and the hyperbolic tangent function is designed to estimate the saturation function for dealing with the input saturation problem. Then, a novel adaptive cascade trajectory tracking control scheme is designed. An adaptive neural network-based terminal sliding control law is proposed for producing the generalized force/moment in real-time, the asymptotic stability of this adaptive control system is proven by Lyapunov theory, and a quasi-newton distribution law is designed to determine the optimum tire forces that guarantee the actual generalized forces/moment are close to the desired values. Finally, simulation results demonstrate the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

The tunnel boring machine(TBM) is a kind of large-scale underground equipment for the tunnel and subway excavations. The cutter-head driving system is one of the key components in hard rock TBM, which is driven by multiple motors to provide enough torque during the excavation. Synchronizing motions of the multiple driving motors and balancing the driving torques are two essential control issues to be addressed of cutter-head driving system. However, the existing synchronization control approaches usually focus on the pure motion synchronization of the multiple driving motors only. These methods will lead to the phenomena of uneven driving torques even when their motions are quite well synchronized, and may result in the shaft broken accident. Instead in this paper, an adaptive robust control law integrated with torque allocation technique scheme is proposed that achieves not only better motion synchronization of the driving motors but also simultaneous regulation of driving torques. Namely, the adaptive robust control (ARC) is introduced to deal with the negative effects from uncertainties and variable load acting on the cutter-head. And a torque allocation algorithm is proposed to distribute the driving torque of each motor evenly. Comparative simulations are carried out to verify the excellent performance of the proposed scheme. [ABSTRACT FROM AUTHOR]

A PI-D based control system is developed for over-actuated, hover-capable AUVs which enables a smooth transition from hover-style to flight-style operation with system stability and convergence proven using a Lyapunov approach. The performance of the controller is demonstrated by simulation and is verified through experiments. The approach is able to operate over a range of vehicle ballasting configurations, and to imposed external disturbances. The proposed system is computationally inexpensive and does not require a detailed hydrodynamic model to implement. By monitoring the energy consumption on board, the cost of maintaining depth at a range of forward speeds with different buoyancy conditions can be quantified, and their impact on the cost of transport is highlighted for future optimisation of energy consumption. [ABSTRACT FROM AUTHOR]

This paper presents a fault-tolerant brake torque controller for four-wheel-distributed braking systems with in-wheel motors and Electro-Mechanical Brakes (EMB). Mechanical and electrical faults can degrade the performance of the EMB actuators and, thus, their effects need to be compensated in vehicle dynamics level. In this study, the faults are identified as performance degradation and expressed by the gains of each actuator. Assuming the brake force distribution and the regenerative braking ratios, the over-actuated braking system is simplified into a two-input system. A sliding mode controller is designed to track the driver's braking and steering commands, even if there exist faults in EMBs. In addition, adaptive schemes are constructed to achieve the fault-tolerant control in braking. The proposed controller and strategies are verified in the EMB HILS (Hardware-in-loop-simulation) unit for various conditions. [ABSTRACT FROM AUTHOR]

The dynamic equation of the morphing wing was obtained based on Lagrange method of analytical mechanics. The skin elastic forces and the aerodynamic load acting on the leading edge were taken into account. Since the morphing wing was a strongly coupled, over-actuated nonlinear system with multi-input and multi-output, a control system of the morphing wing, including control allocator, dynamic inversion controller and PID controllers, was designed. The control allocator was obtained by the pseudo inverse method; the dynamic inversion controller was applied to make the original system decoupled into two independent linear systems; two classical PID controllers were adopted for the linearlized systems. The mathematical model of the, morphing wing was verified via ADAMS simulation. The control system was tested by system simulation using Matlab. The results show that the combination of Lagrange equation, pseudo inverse allocation, dynamic inversion control and classical PID method can effectively solve the dynamic modeling and control problems of the in-plane 2-DOF morphing wing. [ABSTRACT FROM AUTHOR]

This paper provides results of a laboratory experiment designed to illustrate the theoretical control considerations for an over-actuated excitation system. The experiment is based on control of a beam pinned at one end providing a single rotational degree of freedom and excited by two electrodynamic actuators. Control is achieved through implementation of two different control reference techniques: (1) reference based on linear acceleration autospectral densities (ASD) and cross-spectral densities (CSD) using linear accelerometer feedback and (2) reference based on an angular acceleration ASD using estimates of angular acceleration as feedback. Correlations to the theoretical based predictions were conducted based on common measurements of both linear acceleration and estimates of angular acceleration acquired during each trial. [ABSTRACT FROM AUTHOR]