Precision Gravity Center Position Measurement System for Heavy Vehicles

2006 ◽  
Vol 315-316 ◽  
pp. 788-791 ◽  
Author(s):  
Xin Tong Zhao ◽  
H.Z. Jiang ◽  
S.T. Zheng ◽  
Jun Wei Han
Keyword(s):  
Three Dimensional ◽  
Heavy Vehicles ◽  
Position Measurement ◽  
Motion Platform ◽  
Gravity Center ◽  
Inertial Parameters ◽  
Safety Research ◽  
Control Scheme ◽  
Driven System ◽  
Center Position

Knowledge of a vehicle’s inertial parameters is essential for safety research and accident reconstruction. A precision measure system is proposed to determine the weight and gravity center for heavy vehicles. Based on a static gravity measuring principle with three measuring points, a hydraulically driven 2-DOF motion platform is developed. The transfer function model is derived for the hydraulically driven system. By means of a degree-of-freedom control scheme, the platform can realize accurate positioning to construct two intersected planes and work out the three-dimensional coordinates of the vehicle gravity center. Experiments demonstrate that the system has less than 0.3% measurement error in weight, and is able to measure the gravity centre accurately with deviation ≤3mm in X and Y direction, and ≤5mm in Z direction.

Research on Three-Dimensional Displacement Measurement Technology of the Beating Heart

2011 ◽  
Vol 403-408 ◽  
pp. 5182-5186
Author(s):  
Sheng Yi Yang ◽  
An Gu ◽  
Meng Li ◽  
Chang Jian Lu
Keyword(s):  
Heart Surgery ◽  
Classical Mechanics ◽  
Three Dimensional ◽  
Beating Heart ◽  
Displacement Measurement ◽  
Surgical Instruments ◽  
Analytical Models ◽  
Measurement Technology ◽  
Position Measurement ◽  
Mechanics Of Materials

In robotic-assisted heart surgery, the method of canceling the relative motion between the surgical site on the heart and the surgical instruments was introduced in this paper. A whisker sensor was designed for three dimensional position measurement in beating heart surgery. Analytical models were developed according to the classical mechanics of materials, and theoretical formulas were derived for displacement measurement. Feasibility and effectiveness of the method were verified by simulation experiments. We can obtain measurements by loading displacement to the whisker sensor, and draw conclusions by comparing the measurements.

An Acoustic System for Pipeline Profile Measurement

1983 ◽  
Vol 105 (4) ◽  
pp. 475-479
Author(s):  
H. Van Calcar
Keyword(s):  
Measurement Technique ◽  
Measurement System ◽  
Performance Enhancement ◽  
Three Dimensional ◽  
Profile Measurement ◽  
Baseline Measurement ◽  
Acoustic System ◽  
Position Measurement ◽  
Long Baseline ◽  
Hardware Configuration

This paper presents an acoustic position measurement system used for precise three-dimensional flowline profile measurement. The system measures several points along the flowline using the long-baseline measurement technique and augments this measurement with depth telemetry repeaters to maintain elevation accuracy throughout the changing installation geometry. The paper discusses both the measurement system and the performance enhancement features. The paper concludes with a discussion of the hardware configuration and the accuracy that can be expected when the technique is extended into deeper operating areas.

scholarly journals Dynamic target template matching for railway catenary suspension motion detection in wind area

2018 ◽  
Vol 14 (9) ◽  
pp. 155014771879795 ◽  
Author(s):  
Wei Zhou ◽  
Heting Xiao ◽  
Zhonggang Wang ◽  
Lin Chen ◽  
Shaoqing Fu
Keyword(s):  
Template Matching ◽  
Three Dimensional ◽  
Moving Target ◽  
Maximum Relative Error ◽  
Gradual Change ◽  
Matching Method ◽  
Safety Research ◽  
Target Template ◽  
Target Templates ◽  
Dynamic Target

A dynamic target template matching method was proposed to identify railway catenary suspension movements of wind-induced vibration in wind area. Catenary positioning point was taken as the target template, which was compared with equal-sized image sequentially using the proposed matching difference. And, three-dimensional contour map of matching difference value at each sub-area was obtained, where the target pixel coordinates were determined by the minimum matching difference value. Considering the complex imaging condition, the target template was updated by the detected target image to sense the gradual change of illumination conditions like brightness and contrast. Furthermore, to eliminate detecting errors due to wind-induced camera vibration, both static and moving target templates were identified for acquiring the absolute motion of the moving target. Finally, validation test was performed with animation in PowerPoint. The calculated target displacement agrees well with theoretical motion with maximum relative error of 1.8%. And experiment application was conducted at site by analyzing the relationship between detecting displacement and wind speed. Results indicate that the proposed dynamic target template matching method can meet required engineering precision and provide an effective way for wind-vibration safety research of railway catenary system in wind area.

scholarly journals Three-Dimensional Path Planning of Constant Thrust Unmanned Aerial Vehicle Based on Artificial Fluid Method

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yongqiang Qi ◽  
Shuai Li ◽  
Yi Ke
Keyword(s):  
Path Planning ◽  
Unmanned Aerial Vehicle ◽  
Interpolation Method ◽  
Three Dimensional ◽  
Planning Problem ◽  
Perturbation Matrix ◽  
Fluid Field ◽  
Control Scheme ◽  
Aerial Vehicle ◽  
Tangential Vector

In this paper, a three-dimensional path planning problem of an unmanned aerial vehicle under constant thrust is studied based on the artificial fluid method. The effect of obstacles on the original fluid field is quantified by the perturbation matrix, the streamlines can be regarded as the planned path for the unmanned aerial vehicle, and the tangential vector and the disturbance matrix of the artificial fluid method are improved. In particular, this paper addresses a novel algorithm of constant thrust fitting which is proposed through the impulse compensation, and then the constant thrust switching control scheme based on the isochronous interpolation method is given. It is proved that the planned path can avoid all obstacles smoothly and swiftly and reach the destination eventually. Simulation results demonstrate the effectiveness of this method.

The Robust Adaptive Control of Free-Floating Space Manipulator Systems

2001 ◽  
Author(s):  
Chen Li ◽  
Liu Yanzhu
Keyword(s):  
Adaptive Control ◽  
Jacobian Matrix ◽  
Robust Adaptive Control ◽  
Dynamic Equations ◽  
Generalized Jacobian ◽  
Space Manipulator ◽  
Floating Base ◽  
Inertial Parameters ◽  
Control Scheme ◽  
Robust Adaptive

Abstract In this paper, the kinematics and dynamics of free-floating space manipulator systems are analyzed, and it is shown that the Jacobian matrix and the dynamic equations of the system are nonlinearly dependent on inertial parameters. In order to overcome the above problems, the system is modeled as under-actuated robot system, and the idea of augmentation approach is adopted. It is demonstrate that the augmented generalized Jacobian matrix and the dynamic equations of the system can be linearly dependent on a group of inertial parameters. Based on the results, the robust adaptive control scheme for free-floating space manipulator with uncertain inertial parameters to track the desired trajectory in workspace is proposed, and a two-link planar space manipulator system is simulated to verify the proposed control scheme. The proposed control scheme is computationally simple, because we choose to make the controller robust to the uncertain inertial parameters rather than explicitly estimating them online. In particular, it require neither measuring the position, velocity and acceleration of the floating base with respect to the orbit nor controlling the position and attitude angle of the floating base.

Modelling and Adaptive Control of Tendon-Driven Micromanipulators in the Presence of Van-der-Waals Forces

2004 ◽  
Author(s):  
Athanasios Tsoukalas ◽  
Anthony Tzes
Keyword(s):  
Adaptive Control ◽  
Design Problem ◽  
Van Der Waals ◽  
Adaptive Controller ◽  
Simulation Studies ◽  
Unknown Parameters ◽  
Actuation Mechanism ◽  
Control Scheme ◽  
Driven System ◽  
Adaptive Control Scheme

In this article, the design problem of an adaptive controller for a robotic micromanipulator, including the effects of the applied Van der Waals (VdW) forces is considered. The micro-manipulator’s dynamic model is appropriately modified in order to include the interaction of the attractive VdW-forces. Inhere, every link is decomposed into a series of elementary particles (e.g. spheres), each one interacting with the robot’s neighboring objects during its motion. This interaction induces nonlinear additive terms in the model, attributed to the overall effect of the VdW-forces. The actuation is achieved by a tendon-driven system. At each joint, a pair of tendons is attached and act in an almost passive antagonistic manner. The kinematic and dynamic analysis of the tendon-driven actuation mechanism is offered. Consequently, the microrobot’s model is shown to be linearly parameterizable. Subject to this observation, a globally stabilizable adaptive control scheme is derived, estimating the unknown parameters (masses, generalized VdW-forces) and compensating any variations of those. Simulation studies on a 2-DOF micro-manipulator are offered to highlight the effectiveness of the proposed scheme.

Two composite guidance laws based on the backstepping control and disturbance observers with autopilot lag

2019 ◽  
Vol 41 (10) ◽  
pp. 2957-2969 ◽  
Author(s):  
Chaoyuan Man ◽  
Zhenxing Zhang ◽  
Shihua Li
Keyword(s):  
Disturbance Observer ◽  
Three Dimensional ◽  
Simulation Studies ◽  
Missile Guidance ◽  
Nonlinear Disturbance Observer ◽  
First Order ◽  
Guidance Law ◽  
Control Scheme ◽  
Backstepping Controller ◽  
Guidance Laws

A composite three-dimensional (3D) missile guidance law is proposed for manoeuvering targets with the consideration of the first-order autopilot dynamics without any linearization. This guidance law consists of a backstepping controller and a feedforward compensation based on disturbance observers. In this control scheme, the unknown target acceleration is regarded as part of the lumped disturbance, estimated by a disturbance observer, and then feedforward compensated. The backstepping controller is introduced to deal with unmatched disturbances. Moreover, both the nonlinear disturbance observer (NDOB) and the generalized proportional integral observer (GPIO) are employed in the derivation. Simulation studies demonstrate the effectiveness of the proposed guidance law, and compare the guidance performance of the two composite guidance laws with different disturbance observers.

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