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Development of a Low-Noise Bio-Inspired Humanoid Robot Neck
Published in Yunhui Liu, Dong Sun, Biologically Inspired, 2017
Bingtuan Gao, Ning Xi, Jianguo Zhao, Jing Xu
The structure of the developed robotic system is shown in Figure 6.1. The system consists of three main parts: a humanoid robotic unit, a sound insulation box, and a personal computer. The robotic unit has a movable robotic head, a torso, and a height-adjustable support frame used to match humans of different heights either sitting or standing. The size of the head and torso is designed based on the head size of a human adult so that a full-size personal protective uniform fits the robotic system well. The movable robotic head has a 3-DOF neck framework to mimic human neck movements. These movements are driven by the remote motor-based actuators installed in the sound insulation box through the compound cable-and-housing group. The motor-based actuators are controlled by a PC via a peripheral component interconnect (PCI)-based motion controller board, and the control/driven strategy of the motor system is developed and conducted using the PC. Two Omni microphones are installed in the robot head to mimic human ears that can collect the sound information around the robot head effectively. Sensors embedded in the robot neck are capable of measuring its absolute rotation along three orthogonal axes. Signals from the microphones and sensors are collected by the PC through two USB-based data acquisition boards. The main task is to design and develop a humanoid head, sound insulation box, and PC-controller system.
Out-of-Plane Dynamical Strength of Masonry Walls Under Seismic Actions
Published in Journal of Earthquake Engineering, 2023
During the motion, the mechanism changes its geometry. In fact, as the body I of Fig. 4 gains inclination, the rotation center C12, included between the bodies I and II, moves to the right, as shown in Fig. 14. Consequentially, also the absolute rotation center C2 of body II changes position moving to the right and reduces the lengths of the weight rising arms O1, O2, and OQ. This effect is enhanced by the slenderness of the wall. More specifically, in the deformed configuration of the wall, O1 indicates the horizontal distance between the hinge C1 and the center G1, and, likewise, O2 and OQ, respectively, represent the horizontal distances C2 - G2 and C2 - Q, with the point Q placed at the center of the top section of the body II (Fig. 14).
Damage Detection in ALC Exterior Walls in Steel Structural Frames Subjected to Earthquakes Using Acceleration Sensors
Published in Journal of Earthquake Engineering, 2023
Shotaro Yagi, Jun Iyama, Yoshihiro Fukushima, Takanori Ishida, Shoichi Kishiki, Tsuyoshi Seike, Satoshi Yamada
We considered the acceleration sensor “ALC12,” and compared the measured data to those from the displacement transducers, which measured the displacement at the bottom left and bottom right of the panel, as shown in Fig. 3b. Here, it should be noted that the rotation angle measured by the acceleration sensor is an absolute rotation, while the one measured by the displacement transducers is relative to the steel beam deformation on which the sensors are attached. Therefore, it is necessary to consider the deformation of the steel beam. In this specimen, when the top of the steel structural frame was loaded horizontally, the steel structural frame deformed as shown in Fig. 13. For comparison, it is necessary to know the rotation angle where the displacement transducers were located. However, there was no sensor at this position, but an acceleration sensor “S19” was installed at the same position in the other frame, and the data were used for compensation. Figure 14 shows the absolute rotation angle measured by “S19,” denoted by θbeam, and the story drift of the steel structural frame, θframe. The rotation angle on the beam and the story drift are in opposite directions, supporting the assumption of the frame deformation shown in Fig. 13.
Estimation of the trajectory and attitude of railway vehicles using inertial sensors with application to track geometry measurement
Published in Vehicle System Dynamics, 2023
J. González-Carbajal, Pedro Urda, Sergio Muñoz, José L. Escalona
Nowadays, most IMU's used in vehicle dynamics have MEMS-type accelerometers. In contrast to piezoelectric accelerometers, the measured signals include the effect of gravity as follows: where is the array of the accelerometer signals, contains the three components of the absolute acceleration of the IMU in the sensor frame, is the absolute rotation matrix of the IMU, represents the accelerometer noise and g is the acceleration of gravity that is assumed to act in the Z direction. Equation (10) can also be written as where represents the absolute acceleration of the IMU projected onto the TF. It is shown in Ref. [19] that vector can be developed as where V is the forward velocity of the body and , and are the horizontal, vertical and twist curvatures, respectively, of the track centreline. The prime represents differentiation with respect to s.