Cable Control System Research Articles

Automatic Verticality Monitoring and Securing System for Large Circular Steel Pipes

Securing the verticality of foundations is a crucial factor for ensuring safety in offshore construction. The repeated intrusion-pulling method is generally used to ensure verticality in suction bucket foundation construction processes. However, it relies heavily on the experience and skills of field workers and is relatively time-consuming. To address this problem, we propose an automatic verticality securing system for large circular steel pipes based on a verticality monitoring system. This system adjusts cables at locations where verticality correction is required without changing the existing suction pile–penetration–construction process. It includes a monitoring component that provides real-time data on pipe alignment and an automatic lifting cable control system that maintains perpendicularity using data acquired from the monitoring system. The monitoring system comprises a sensor, an embedded controller, and a display program that displays the vertical information of circular steel pipes. The automatic lifting cable control system includes a controller with an algorithm for adjusting the length of the actuator. We showed that the system operates satisfactorily and secures the verticality of less than 0.2° in the suction bucket-based model experiment. Furthermore, the testbed experimental results show that our monitoring system can efficiently measure verticality information in real time.

Some Comments on Fatigue Life Tests of Aircraft Cable Control Systems

Abstract Cable control systems are widely used in aircraft and gliders. This paper deals with the problem of collecting real loads acting cable control systems and cable tests preparation (load spectrum) and performance. The author proposes a method for defining real loads acting on control systems, preparing and carrying out fatigue tests of cables revealing symptoms of fretting. The fatigue tests results can be used to predict service life, to plan and prepare periodic and details inspections. This method could be used to increase service life of aircraft control cables and could help to replace the commonly used Time-Based Maintenance (TBM) strategy with the Damage Tolerance (DT).

A Prosthetic Gripper with Three Opposing Fingers Driven by a Hydraulic Actuator.

Electric prosthetic hands have problems of heavyweight, unsuitability for working near water, and driving noise. Although body-powered prosthetic hands solve these problems, they have operability and wearability problems related to a cable control system. In this paper, we report a prosthetic gripper with three opposing fingers driven by a hydraulic actuator without electrical components. The three fingers are controlled simultaneously by pushing the lever of an operating interface mounted on the user's upper arm on the affected side. The hydraulic actuator enables users to open the fingers with a force of 16.6 N. The operating interface can be worn without a harness. The total weight is 316 g. Grasping tests of abstract and daily objects in which two amputees participated demonstrated that two amputees were able to grasp various objects. Quietness was also confirmed by them.

Adaptive MR damper cable control system based on piezoelectric power harvesting

To reduce the vibration of cable-stayed bridges, conventional magnetorheological (MR) damper control system (CMRDS), with separate power supply, sensors and controllers, is widely investigated. In this paper, to improve the reliability and performance of the control system, one adaptive MR damper control system (AMRDS) consisting of MR damper and piezoelectric energy harvester (PEH) is proposed. According to piezoelectric effect, PEH can produce energy for powering MR damper. The energy is proportional to the product of the cable displacement and velocity. Due to the damping force changing with the energy, the new system can be adjustable to reduce the cable vibration. Compared with CMRDS, the new system is structurally simplified, replacing external sensor, power supply and controller with PEH. In the paper, taking the N26 cable of Shandong Binzhou Yellow River Bridge as example, the design method for the whole AMRDS is given, and simple formulas for PEH are derived. To verify the effectiveness of the proposed adaptive control system, the performance is compared with active control case and simple Bang-Bang semi-active control case. It is shown that AMRDS is better than simple Bang-Bang semi-active control case, and still needed to be improved in comparison with active control case.

Stiffness Calculation and Predetermined Preload Optimal Design of Cable Control System

The stiffness of cable flight control systems is one of the most important design parameter for aviation aircraft, because it can change the characteristic of control stick and influence the maneuverability and stability of the flight control system. Flexible cable control system is the main type of mechanical flight control system, in which movement can only be transmitted by cable in tension, the stiffness of cable control system is affected mainly by predetermined preload(PP), however the excessive PP would increase friction between cable and pulley which leads pilot an unfavorable maneuver. In this paper, the theoretical stiffness calculation of cable control system with the complex cable braided construction has been calculated and discussed, in addition the effects of cable deflection and linkage pulley are taken into account to obtain a precise stiffness calculation, and also the predetermined preload related to friction is studied through numerical example, as well as the numerical results have been compared with the experimental results.

The Seven Parameters of Highly Effective Cable Control Systems

The Seven Parameters of Highly Effective Cable Control Systems

B211 体内力源型能動義手ケーブル駆動システムの力学に基づく調整法のための基礎実験(B2-2 福祉工学2)

B211 体内力源型能動義手ケーブル駆動システムの力学に基づく調整法のための基礎実験(B2-2 福祉工学2)

Is body powered operation of upper limb prostheses feasible for young limb deficient children?

The investigators measured efficiencies of body powered prehensors and cable control components of prostheses available for young children. Results indicated that the cable control systems and hook type prehensors have moderate to high efficiencies, but children's body powered hands have very low efficiencies. Measures of arm and shoulder strength of 3-5 year-old limb deficient children, both on the limb deficient and sound sides, were less than that reported in the sound sides, were less than that reported in the literature for normal children. The findings were examined in relation to children's strength available compared with prosthesis strength requirements. The comparison demonstrates a way to establish measurable efficiency targets for new prehensor designs. The article includes detailed findings on children's strength, and findings on efficiencies of the prehensors and cable control systems of children's upper limb prosthses. Sample calculations may be useful to future designers of body powered prehensors for young children. A more efficient body powered hand is especially needed. Preliminary calculations indicate that the use of currently available children's voluntary opening (VO), body powered hands is not feasible, given the low strength of young limb deficient children and the low efficiencies of the VO hands. The use of voluntary closing (VC) hands may be feasible but remains to be tested.

Current evaluation of hydraulics to replace the cable force transmission system for body-powered upper-limb prostheses.

Present body-powered upper-limb prostheses use a cable control system employing World War II aircraft technology to transmit force from the body to the prosthesis for operation. The cable and associated hardware are located outside the prosthesis. Because individuals with arm amputations want prostheses that are natural looking with a smooth, soft outer surface, a design and development project was undertaken to replace the cable system with hydraulics located inside the prosthesis. Three different hydraulic transmission systems were built for evaluation, and other possibilities were explored. Results indicate that a hydraulic force transmission system remains an unmet challenge as a practical replacement for the cable system. The author was unable to develop a hydraulic system that meets the necessary dynamic requirements and is acceptable in size and appearance.

Improving the dynamic response of airplanes by means of electric equipment

This paper begins with an elementary discussion of the mechanics of airplane flight and control. Following this discussion electrical methods for improving the transient response of an airplane in the yawing and pitching modes are outlined and illustrated by two examples. The paper is concluded by a brief discussion of a method by which an airplane cable control system can be replaced by an electric servomechanism. Results of analyses using differential equations and Nyquist plots are discussed and compared with results obtained on an analogue computer.