THE LOADS ON YACHT ANCHOR CABLES

The loads exerted on an all-chain anchor cable of a 10m yacht were measured during full scale trials in sheltered waters and steady wind. The peak recorded load was found to decrease significantly with increasing scope ratio, whereas the mean load was only weakly affected by scope ratio. The trials results were used to calculate the depth of water in which the pull at the anchor just remains horizontal for a range of wind speeds and cable lengths. The resulting relationship between maximum water depth and cable length is approximately quadratic. The required scope ratio for a given water depth increases with increasing windspeed. The required scope ratio for a given windspeed decreases with increasing depth.

Influence of System Layout on CM EMI Noise of SiC Electric Vehicle Powertrains

This paper investigates the influences of system layout on common mode (CM) EMI noise of an electric vehicle (EV) powertrain with a traction inverter using silicon carbide (SiC) MOSFETs. First, a system level conducted EMI model for the whole SiC EV powertrain is presented, which includes a battery pack, DC cables, a SiC inverter, AC cables, and a PMSM. Then, the impacts of system layout, such as the AC cable length, the AC cable type, and the DC cable type (shielded cable and unshielded cable) on CM EMI noise are analyzed through time domain simulations of the system level conducted EMI model. Next, a conducted EMI emission test-bed for a SiC EV powertrain is built. Finally, experiments on the test-bed are carried out to verify the influences of system layout on CM EMI noise in the SiC EV powertrain.

Kinematic Analysis and Motion Planning of Cable-Driven Rehabilitation Robots

In this study, a new cable-driven rehabilitation robot is designed, the overall design of the robot is given, and the kinematic equation of the lower limbs in the supine state of the human body is addressed. Considering that cable winders move along the rail brackets, the closed vector method is applied to establish the kinematic model of the robot, and the relationship between the human joint angle and the cable length change was deduced. Considering joint compliance, a fifth-order polynomial trajectory planning method based on an S-shaped curve is proposed by introducing an S-shaped velocity curve, and the changes in cable length displacement, velocity, and acceleration are simulated and analyzed. Three planning methods are compared based on two indices, and experimental verification is carried out on the rehabilitation experiment platform. The simulation and experimental results show that the trajectory planning method presents low energy consumption and strong flexibility, and can achieve better rehabilitation effect, which builds a good basis for the subsequent study of dynamics and control strategy.

Optimization and Form-finding of the Heavy Cable Suspending a Deck

The heavy spanning cable supporting a uniform deck is important in the design of suspension bridges. The analytic design method is presented in this paper. The problem depends on three non-dimensional parameters: the ratio of cable length to the horizontal spanning distance, the ratio of vertical to horizontal distance, and the ratio of deck density to cable density. Given these parameters, useful tables of maximum tension and sag are determined. There exists an optimum cable length for which the maximum tension is minimized. In addition, it is shown that continuous loads and discrete loads are equivalent if the number of evenly-spaced discrete loads are more than 10.

Analysis on the Influence Degree of Deformation Control Factors of Deep-Buried Roadway’s Fractured Surrounding Rock Using Orthogonal Design

It is a complex issue to select the support structure parameters for a deep-buried roadway with fractured surrounding rock; especially when the support structure parameters need to be adjusted, the influence degree of support structure parameters on roadway deformation needs to be determined. The deformation of deep-buried roadway’s fractured surrounding rock development was investigated using multi-index orthoplan in this paper. According to the coal mine field investigation, support structure’s failure often occurs, and some need to be repaired many times. Through the roadway surrounding rock drilling, it was found that the stress of the surrounding rock was relieved, resulting in the cavity and separation of the stratum layer. The two sidewalls’ development and roof fractures are mainly tangential, and the original rock state appears only beyond 6.3∼8.2 m. The length of bolts, the row distance between bolts, the length of cables, and the row distance of U-shaped steel were selected as control factors in the multi-index orthogonal design, and roadway’s deformation values were taken as the test indexes. According to the orthoplan, nine numerical simulation schemes were designed, and FLAC3D was used for establishment. The range analysis method was used to analyze the test results. The results show that the control factors’ influence order on the total deformation of the roadway is as follows: row spacing between U-shaped steel > bolt length > cable length > row spacing between bolts, the influence order on the deformation of the roadway floor is as follows: row spacing between U-shaped steel > row spacing between bolts > bolt length > cable length, same as the left sidewall and right sidewall, and the influence order on the roadway roof’s deformation is as follows: row spacing between U-shaped steel > bolt length = cable length > row spacing between bolts, which provide a reference for the support design of deep-buried roadways with fractured surrounding rock, especially the adjustment of the supporting structure.

A Laser-Based Direct Cable Length Measurement Sensor for CDPRs

Accuracy improvement is an important research topic in the field of cable-driven parallel robots (*CDPRS). One reason for inaccuracies of *CDPRS are deviations in the cable lengths. Such deviations can be caused by the elongation of the cable due to its elasticity or creep behavior. For most common *CDPRS, the cable lengths are controlled using motor encoders of the winches, without feedback about the actual elongation of the cables. To address this problem, this paper proposes a direct cable length measurement sensor based on a laser distance sensor. We present the mechanical design, the first prototype and an experimental evaluation. As a result, the measurement principle works well and the accuracy of the measured cable lengths is within −2.32 mm to +1.86 mm compared to a range from −5.19 mm to +6.02 mm of the cable length set with the motor encoders. The standard deviation of the cable length error of the direct cable length measurement sensor is 58% lower compared to the one set with the motor encoders. Equipping all cables of the cable robot with direct cable length measurement sensors results in the possibility to correct cable length deviations and thus increase the accuracy of *CDPRS. Furthermore, it enables new possibilities like the automatic recalibration of the home pose.

Impacts of Lightning-Induced Overvoltage on a Hybrid Solar PV–Battery Energy Storage System

With increased electrical energy demands projected in the future, the development of a hybrid solar photovoltaic (PV)–battery energy storage system is considered a good option. However, since such systems are normally installed outdoors and in open areas, they are vulnerable to lightning strikes and may suffer from malfunctions or significant damage to sensitive components, which may result in a major breakdown and loss of revenue due to equipment replacement costs and inefficient operation. Thus, the objective of this paper is to investigate the effect of lightning-induced overvoltage on a hybrid solar PV–battery energy storage system, considering indirect lightning strikes nearby the system. The presented hybrid solar PV–battery energy storage system and lightning-induced overvoltage are modeled in Electro-Magnetic Transient Program-Restructured Version (EMTP-RV) software. The lightning-induced overvoltage is simulated based on a lightning waveshape of 10/350 µs using the Heidler expression, whilst the Rusck model is used to simulate the lightning-induced overvoltage. Different lightning current amplitudes (3, 19, and 169 kA), lightning strike locations (20, 50, and 100 m), and cable lengths (5, 10, and 20 m) are used to investigate the induced effects on the system and on the impulse withstand voltage of 6kV, as stated in MS IEC 60664-1 for solar PV–battery systems and inverters at the DC side. The results indicate that as the lightning strike distance increases from 20 to 100 m, the percentage of strikes exceeding the impulse withstand voltage reduces from 67% to 54% at 19 kA. At 169 kA, the impulse withstand voltage is exceeded by more than 100%, regardless of the strike distance (from 20 to 100 m). Furthermore, differences in cable length do not have much impact on the lightning-induced overvoltage due to the small voltage drop across the short cable length. This study provides useful information for PV systems owners and will be useful in assigning appropriate lightning protection schemes for PV farms.

Scaling of subcellular structures with cell length through decelerated growth

How cells tune the size of their subcellular parts to scale with cell size is a fundamental question in cell biology. Until now, most studies on the size control of organelles and other subcellular structures have focused on scaling relationships with cell volume, which can be explained by limiting pool mechanisms. Here, we uncover a distinct scaling relationship with cell length rather than volume, revealed by mathematical modeling and quantitative imaging of yeast actin cables. The extension rate of cables decelerates as they approach the rear of the cell, until cable length matches cell length. Further, the deceleration rate scales with cell length. These observations reveal a new mode of scaling that senses the linear dimensions of a cell.One Sentence SummaryAs actin cables in yeast cells grow longer, their extension rate decelerates, enabling the cable length to match cell length.