Balancing inverted pendulum cart on inclines using accelerometers

ASME Letters in Dynamic Systems and Control ◽

10.1115/1.4052712 ◽

2021 ◽

pp. 1-6

Author(s):

Cole Woods ◽

Vishesh Vikas

Keyword(s):

Inverted Pendulum ◽

Error Function ◽

Incline Angle ◽

Future Design ◽

Inclined Surfaces ◽

Inclination Angles ◽

Rotational Equilibrium ◽

Control Feedback ◽

Gravity Acceleration ◽

Contact Sensors

Abstract The balance of inverted pendulum on inclined surfaces is the precursor to their control in unstructured environments. Researchers have devised control algorithms with feedback from contact (encoders - placed at the pendulum joint) and non-contact (gyroscopes, tilt) sensors. We present feedback control of Inverted Pendulum Cart (IPC) on variable inclines using non-contact sensors and a modified error function. The system is in the state of equilibrium when it is not accelerating and not falling over (rotational equilibrium). This is achieved when the pendulum is aligned along the gravity vector. The control feedback is obtained from non-contact sensors comprising of a pair of accelerometers placed on the inverted pendulum and one on the cart. The proposed modified error function is composed of the dynamic (non-gravity) acceleration of the pendulum and the velocity of the cart. We prove that the system is in equilibrium when the modified error is zero. We present algorithm to calculate the dynamic acceleration and angle of the pendulum, and incline angle using accelerometer readings. Here, the cart velocity and acceleration are assumed to be proportional to the motor angular velocity and acceleration. Thereafter, we perform simulation using noisy sensors to illustrate the balance of IPC on surfaces with unknown inclination angles using PID feedback controller with saturated motor torque, including valley profile that resembles a downhill, flat and uphill combination. The successful control of the system using the proposed modified error function and accelerometer feedback argues for future design of controllers for unstructured and unknown environments using all-accelerometer feedback.

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A Bolt-Nut Loosening Mechanism in Bolted Connections Under Repeated Transverse Loadings (Effect of Inclined Bearing Surfaces on the Loosening)

ASME 2010 Pressure Vessels and Piping Conference: Volume 2 ◽

10.1115/pvp2010-25324 ◽

2010 ◽

Author(s):

Toshiyuki Sawa ◽

Mitsutoshi Ishimura ◽

Atsushi Karami

Keyword(s):

Testing Machine ◽

Bolted Joints ◽

Incline Angle ◽

Impact Loads ◽

Screw Thread ◽

Bolted Joint ◽

Bearing Surface ◽

Bolted Connections ◽

Inclined Surfaces ◽

Thermal Changes

Loosening accidents sometimes occur under several types of loadings such as winds, vibrations, earthquakes, impact loads and thermal changes. Recently, some studies have been conducted on the screw thread loosening in bolted joints under repeated transverse loadings. It is well known that bolted joints are easily loosened when repeated transverse loadings are applied. While, in assembling bolted joints, the contact surfaces between a bolt head/nut and a clamped part are inclined geometrically. However, a lot of researches have dealt with the bolted joints in which the bearing surfaces are perfectly contacted without the inclined surfaces. Thus, it is necessary to examine the incline of the bearing surfaces on the loosening in bolted joint. A lot of parts for preventing the loosening have been proposed and sold at market. Among these parts, the authors have demonstrated that eccentric nuts are especially expected to be the solution for preventing the loosening of the joints under repeated transverse loadings. However, a few studies have been carried out on the loosening and loosening mechanism in bolted joints with inclined bearing surface and the effective solution for preventing loosening of bolted joint with the inclined bearing surfaces under the repeated transverse loadings. Thus, it is necessary to examine the effect of the incline at the bearing surfaces on the loosening and to evaluate the solutions for preventing loosening of the bolted joints with the inclined bearing surfaces. In this study, the effect of the incline at the bearing surfaces on the loosening is examined using FEM calculations. In the FEM calculations, the incline angle at the bearing surfaces is changed as 0, 2 and 3 degree, respectively. The experiments to measure the loosening in bolted joints were carried out using Junker’s testing machine to validities of the FEM calculations for revealing the effect of the loosening in the joints with the inclined bearing surfaces. In addition, nut parts for preventing the loosening in bolted connections with the inclined bearing surface under repeated transverse loadings are examined using the FEM calculations. As the result, it is seen that the loosening increases as the angle of incline increases. In addition, it is observed that bolted joints in which almost nut parts for preventing loosening are applied are loosened easily while the eccentric nut does not loosened. Discussion is made on the loosening mechanism in bolted joints under repeated transverse loadings.

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Postural stability during task performance on elevated and/or inclined surfaces

Occupational Ergonomics ◽

10.3233/oer-2003-3201 ◽

2003 ◽

Vol 3 (2) ◽

pp. 83-97 ◽

Cited By ~ 1

Author(s):

Amit Bhattacharya ◽

Paul Succop ◽

Laurel Kincl ◽

Ming Lun Lu ◽

Angshuman Bagchee

Keyword(s):

Perceived Risk ◽

Postural Stability ◽

Postural Sway ◽

Objective Measure ◽

Compensatory Mechanism ◽

Industrial Workers ◽

Inclined Surfaces ◽

Postural Muscle ◽

Inclination Angles ◽

Environmental Lighting

The purpose of this study was to subjectively and objectively evaluate the postural stability of forty industrial workers while performing simulated industrial tasks on inclined and elevated surfaces under various combinations of environmental lighting and noise distraction conditions. The results suggest the following ordering for the effects of risk factors on objective measure of postural balance: (1) environmental lighting, (2) elevation of standing surface, (3) gender, (4) inclination of standing surface, (5) age. The task performed would be ranked highest had the data been analyzed across the three tasks. The postural sway length significantly increased with increasing elevations and inclination angles for the stationary and bending tasks implying body's perceived risk of fall deployed increase in postural muscle contraction. This compensatory mechanism indicated by increased sway length actually did reduce postural sway amplitudes with increasing elevation but for increasing inclination the postural sway amplitudes increased. While the objective measure of postural sway increased with the increasing combination of elevation and inclination, the subjective measure of stability did not show a significant two way interaction, implying that the participants were not able to perceive the combined risk to postural imbalance, causing potential inability to deploy appropriate postural muscle corrective actions.

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Surface roughness effect on droplet impact characterization: Experimental and theoretical study

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.13.2.2019.23.0420 ◽

2019 ◽

Vol 13 (2) ◽

pp. 5104-5125

Author(s):

J. Zohrabi Chakaneh ◽

S. M. Javid ◽

M. Passandideh-Fard

Keyword(s):

Surface Roughness ◽

High Speed ◽

Droplet Formation ◽

Droplet Impact ◽

Experimental Results ◽

Analytical Models ◽

Incline Angle ◽

Secondary Droplet ◽

Inclined Surfaces ◽

The Impact

In this paper, the effect of surface roughness on the both normal and inclined droplet impact is investigated experimentally by image processing. The impingement of water droplets with 2.9 mm diameter and 1m/s velocity impacting on three types of stainless steel surfaces with respective arithmetic average surface roughness values of 2.24 μm (Smooth), 6.04 (Medium) and 30.2 (Rough) is examined using a high-speed camera. The dynamic behavior of the impact including droplet deformation, the maximum spreading diameter and length, contact angle and the number of fingers are studied. Experimental results demonstrate that rough surfaces not only prevent secondary droplet formation but also decrease the number of fingers formed around the droplet in the normal droplet impact. Considering the inclined droplet impact scenarios, the asymmetric spreading of droplet on inclined surfaces avoids the secondary droplet formation by decreasing the fluid kinetic energy. In the inclined impact, fingers are formed around the droplet perimeter like the normal impact. The only difference between impacts onto the inclined surfaces is a gradual decrease of the number of fingers by increasing the incline angle. The experimental results are compared with those of the analytics available in the literature for the normal droplet impacts. Next, a simple analytical model for droplet impact on an inclined surface is developed; the predictions from this model was also compared to those of measurements. Calculated values from the analytical models agreed well with experimental data for both normal and inclined impact scenarios.

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Surface Texture Characterization of Metal Selective Laser Melted Part With Varying Surface Inclinations

Journal of Tribology ◽

10.1115/1.4050455 ◽

2021 ◽

Vol 143 (5) ◽

Author(s):

Shubhavardhan Ramadurga Narasimharaju ◽

Weidong Liu ◽

Wenhan Zeng ◽

Tian Long See ◽

Paul Scott ◽

...

Keyword(s):

Surface Texture ◽

Measurement Data ◽

Particle Analysis ◽

Inclined Surfaces ◽

Staircase Effect ◽

Inclination Angles ◽

Surface Inclination ◽

Texture Characterization ◽

The Impact ◽

Areal Surface

Abstract Additive manufacturing offers the advantage of infinite freedom to design and fabricate complex parts at reduced lead-time. However, the surface quality of additively manufactured parts remains well behind the conventionally processed counterparts. This paper aims to systematically investigate the impact of varying surface inclination angles with respect to the build direction on the resultant surface textures. A bespoke metal truncheon artifact with inclination angles varying from 0 deg to 180 deg was built by selective laser melting. Focus variation microscopy was used to measure the topography of inclined surfaces with a tilt angle of up to 132 deg. The measurement data were then analyzed to characterize the staircase effect and the particles adherent to the artifact surface. Areal surface texture parameters, including height parameters, spatial parameters, functional parameters, and feature parameters, were explored to quantify the general surface topography, the staircase effect, and the particle features. The areal surface texture characterization and particle analysis reveal the resulted surface topographies are strongly correlated with the surface inclination angles.

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Quantitative energy-filtered electron diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172693 ◽

1994 ◽

Vol 52 ◽

pp. 992-993

Author(s):

R. Vincent

Keyword(s):

Electron Diffraction ◽

Inelastic Scattering ◽

Dynamic Range ◽

Electron Optics ◽

Surface Layers ◽

High Brightness ◽

Inclined Surfaces ◽

Perfect Symmetry ◽

Amorphous Surface ◽

The Ideal

Microanalysis and diffraction on a sub-nanometre scale have become practical in modern TEMs due to the high brightness of field emission sources combined with the short mean free paths associated with both elastic and inelastic scattering of incident electrons by the specimen. However, development of electron diffraction as a quantitative discipline has been limited by the absence of any generalised theory for dynamical inelastic scattering. These problems have been simplified by recent innovations, principally the introduction of spectrometers such as the Gatan imaging filter (GIF) and the Zeiss omega filter, which remove the inelastic electrons, combined with annual improvements in the speed of computer workstations and the availability of solid-state detectors with high resolution, sensitivity and dynamic range.Comparison of experimental data with dynamical calculations imposes stringent requirements on the specimen and the electron optics, even when the inelastic component has been removed. For example, no experimental CBED pattern ever has perfect symmetry, departures from the ideal being attributable to residual strain, thickness averaging, inclined surfaces, incomplete cells and amorphous surface layers.

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312. Use of Visual Cues in Reducing the Risk of Fall During Work at Elevated and/or Inclined Surfaces

10.3320/1.2765449 ◽

1999 ◽

Author(s):

A. Bagchee ◽

A. Bhattacharya ◽

P. Succop ◽

M. Medvedovic

Keyword(s):

Visual Cues ◽

Inclined Surfaces ◽

Risk Of Fall

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Sun Load Analysis and Testing on Automotive Front Lighting Products

Light & Engineering ◽

10.33383/2019-026 ◽

2020 ◽

pp. 116-122

Author(s):

Emre Öztürk ◽

Mehmet Aktaş ◽

Tunç Şenyüz

Keyword(s):

Prolonged Exposure ◽

Hot Spot ◽

Load Test ◽

Angle Of Incidence ◽

The Sun ◽

Solar Simulator ◽

Automotive Lighting ◽

Inclination Angles ◽

Plastic Parts ◽

Load Simulation

The purpose of this research is to reach good correlation between sun load simulation and solar focusing test for exterior automotive lighting products. Light coming from sun is highly collimated (parallel rays) and focusable from lenses with concave structure. Focusing incidence leads to a hot spot on lens surrounding plastic parts which may cause melting failures at high temperature zones. Sun load simulation is performing to eliminate risk of discoloration, deformation, out gassing, coating failures and fire with prolonged exposure from field. Irradiance values in W/m2 defined in simulation as heat source depending of an angle of incidence of the sun radiation. At first step, simulation is performing with 5 degree intervals to define the critical zones then intervals decreased to 2 degree to detect the critical azimuth and inclination angles. Critical azimuth and inclination angles is checking with ray trace analysis to check the bouncing of sun rays and possible solution to eliminate focuses with design solutions. After numerical analysis to release and validate the automotive lighting products regarding the sun load test, measurement with first parts is necessary. Measurement is performing for all critical angles which have been detected at simulation with thermal camera under ultra high-collimation solar simulator. Measured temperatures are settled according to environment conditions and correlation is checking with simulations.

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