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Dive into the research topics where Christopher C. Jobes is active.

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Featured researches published by Christopher C. Jobes.


2010 IEEE International Workshop on Robotic and Sensors Environments | 2010

Development of a method to determine operator location using electromagnetic proximity detection

Jacob L. Carr; Christopher C. Jobes; Jingcheng Li

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are advancing the emerging technology of electromagnetic proximity detection, which provides a promising means of protecting workers around any machinery that presents striking, pinning or entanglement hazards. This technology is particularly applicable to mobile underground mining equipment such as remote-control continuous mining machines, which offer perhaps the most difficult safety challenges in the mining industry. Other industries have effectively implemented proximity detection technology, with successful test cases at surface and underground mines. However, applying this technology to remote-control continuous mining machines presents uniquely difficult challenges. These machines typically weigh close to 100,000 pounds and have heavy, articulated parts. Due to visibility and space limitations, machine operators often work in very close proximity to the machine despite the clear hazards that this proximity creates. To protect miners without preventing them from doing their jobs or causing nuisance alarms, intelligent electromagnetic proximity detection technology is now being developed at the NIOSH research facility in Pittsburgh. At the heart of this technology are a number of electromagnetic field generators mounted on a mining machine and magnetic flux density sensors built into a Personal Alarm Device (PAD) worn by the operator. In this paper, the authors present a novel algorithm created to calculate an accurate position based on PAD readings from multiple field generators coupled with a previously developed model of the generated magnetic field. The use of this algorithm allows for the calculation of an accurate PAD location relative to the mining machine. A prototype of this intelligent proximity detection system has been successfully implemented and demonstrated on a Joy 14CM continuous mining machine at the NIOSH research facility in Pittsburgh. This technology has the potential to significantly affect the mining industry by greatly advancing the current state-of-the-art in proximity detection technology, leading to increased operator safety and preventing serious injuries and fatalities.


Volume 5: 13th Design for Manufacturability and the Lifecycle Conference; 5th Symposium on International Design and Design Education; 10th International Conference on Advanced Vehicle and Tire Technologies | 2008

Comparison of Whole-Body Vibration Exposures on Older and Newer Haulage Trucks at an Aggregate Stone Quarry Operation

Alan G. Mayton; Christopher C. Jobes; Richard E. Miller

Exposure to whole-body vibration (WBV) and the postural requirements of the job have been identified as important risk factors in the development of musculoskeletal disorders of the back among workers exposed to a vibratory environment. This paper focuses on preliminary results of WBV data collected for two groups of haulage trucks — four older trucks from manufacturer A (MFR-A) and two newer trucks from manufacturer B (MFR-B). All of the trucks and their respective seats were considered to be in good working order during the study. Measurement periods for the truck groups had similarities, but varied from 2 to 58 minutes. Sampling times for the older trucks included a mean of 19.5 minutes and a standard deviation (STD) of 6.5 minutes compared to a mean of 40.8 minutes and a STD of 12.1 minutes for the newer trucks. Data collection coincided with the approximate delivery and first operation of the new trucks, and occurred approximately 12 months apart under similar weather and road conditions, and with the same drivers except an additional driver was included with the older trucks. Truck routes were somewhat different in that quarry production had changed location in the time between data collection activities. Overall, the results suggest that the newer trucks may provide better overall isolation to drivers/operators from WBV exposure compared to the older trucks operating at the quarry; although, this will need to be confirmed with additional measurements. Considering the higher variability and shorter sampling times for the older trucks, the results should be viewed with caution. For two of seven trials, the older trucks showed that seats amplified vibration, i.e., a transmissibility (T) >1.0. Seat T for the older trucks ranged from 0.31 to 1.17 with a mean of 0.77 and STD of 0.32. This contrasted with the newer haulage trucks where seats amplified vibration in 3 of 8 trials. In this case, T did not vary greatly and ranged from 0.87 to 1.05 with a mean of 0.97 and STD of 0.07. Regarding older trucks, in five of seven trials, the seat (output) data of weighted root-mean square (RMS) acceleration (wRMSz ) for the dominant z-axis exceeded the action level of 0.5 m/s2 action level recommended by the European Union Good Practice Guide for WBV (EUGPG) and levels exceeded the recommended exposure limit of 1.15 m/s2 in two of the seven trials. The wRMSz values for the older trucks varied from 0.41 to 1.83 m/s2 with a mean of 0.99 and STD of 0.57. Similarly, newer trucks indicated a narrower range of wRMSz from 0.38 to 0.95 m/s2 . The mean wRMSz was lower for the newer trucks at 0.58 m/s2 with a STD of 0.23 m/s2 . Similarly, newer trucks indicated wRMSz reached or exceeded the action level in four of eight trials. None of the trials with the new trucks showed wRMSz levels that reached or exceeded the recommended 1.15 m/s2 exposure limit. As an indicator of driver/operator discomfort, overall weighted total RMS acceleration (vector sum) values seem to show a “rougher” ride for the older trucks. The vector sum values for these trucks ranged widely from 0.70 to 2.59 m/s2 and, in four of seven trials, showed levels greater than 1.40 m/s2 . The mean vector sum was 1.44 m/s2 with a STD of 0.75 m/s2 . Comparatively, the newer trucks exhibited less variation with a range from 0.69 to 1.59 m/s2 . The mean vector sum was 1.02 m/s2 with a STD of 0.35 m/s2 . Vibration dose values for the dominant z-axis (VDVz ), gave a sense of vehicle jarring/jolting conditions. All trials with the older trucks were within the recommended EUGPG action level of 9.1 m/s1.75 . On the other hand, in three of eight trials, both newer trucks exceeded this action level with values of 9.18, 12.58, and 13.21 m/s1.75 . Neither truck group showed VDVz that exceeded the exposure limit of 21 m/s1.75 . A statistical analysis was not conducted, since the differences reported between truck groups may not be statistically significant owing to the relatively small sample size. Road conditions, changes in the truck routes, and driver/operator differences (e.g., stopping and turning) are possible factors in the higher VDV for the newer trucks.


Design Engineering and Computers and Information in Engineering, Parts A and B | 2006

Laboratory Investigation of Seat Suspension Performance During Vibration Testing

Alan G. Mayton; Joseph P. DuCarme; Christopher C. Jobes; Timothy J. Matty

Mining injury statistics show that a significant number of back, neck, and head injuries are linked to exposure from vehicle vibration. Use of a suspension seat is a common way to isolate the vehicle operator from the adverse effects of vibration exposure. Thus, researchers at the National Institute for Occupational Safety and Health1 - Pittsburgh Research Laboratory (NIOSH - PRL) performed laboratory studies on four passive and two semi-active seat suspension designs. These are typical of seat suspensions commonly found on large off-road heavy surface mining, construction and agricultural vehicles as either replacement or original equipment manufacturer (OEM) systems. One included a pneumatic (air bladder) spring mechanism. The fifth and sixth suspensions were a NIOSH magnetorheological (MR) semi-active damper design based on the pneumatic (air bladder) and one of the coil spring suspensions above. These suspensions were modified with a commercially available MR damper substituted for the OEM damper. These six seat suspension systems were tested and analyzed, for vertical vibration only, using the ISO 5007 Standard [1]. This paper describes the laboratory vibration tests using a MTS® shaker table and discusses the results obtained for the different suspension designs and highlights the rheonetic technology studied. Implications of the seat suspension designs relative to their capabilities for isolating vehicle operators from vibration exposure are discussed. Results for suspensions 1 through 3 showed frequencies of isolation from 2.1 to 3.0 Hz using the 40-kg (88-lb) mass and from 1.65 Hz to 1.8 Hz using the 80-kg (176-lb) mass. Suspension #4, in tests with only the 80-kg (176-lb) mass, showed an isolation frequency of 3.7 Hz. With the MR damper added to seat suspension #4, the peak transmissibility was lowered from 1.3 to 0.95 and showed a corresponding downward shift in frequency from 2.25 Hz to 1.4 Hz. In fact, the results for suspension #5 (the MR damper added to seat suspension #4), using test #3 conditions of the programmed control algorithm, showed isolation (attenuation of transmitted vibration) throughout the test frequency range from 1.0 to 6.0 Hz.© 2006 ASME


IEEE Transactions on Industry Applications | 2013

Comparison of Magnetic Field Distribution Models for a Magnetic Proximity Detection System

Jingcheng Li; Christopher C. Jobes; Jacob L. Carr

Magnetic proximity detection technology is rapidly advancing as a promising method of protecting underground mine workers from striking and pinning hazards associated with mobile mining machines. A magnetic proximity detection system requires a magnetic distribution model to estimate the proximity of the sensor to the generators. This paper presents a comparative analysis of magnetic flux density distribution models in three different field distribution design patterns. The accuracy of these models is determined with a laboratory magnetic proximity detection system. These field distribution design patterns are spherical, ellipsoidal, and sphere-cosine, respectively. The analyses show that the sphere-cosine model is the most accurate model for the proximity system followed by the ellipsoidal and spherical models.


SAE World Congress & Exhibition | 2007

Comparison of passive seat suspension with different configuration of seat pads and active seat suspension

Bertrand Valero; Farid Amirouche; Alan G. Mayton; Christopher C. Jobes

Exposure to vibration induced in and around underground m ine’s exploration is a m ajor concern to vehicles operators. Most of these drivers over time develop serious spinal musculoskeletal and discs problems causing low back injuries. The first purpose of this paper is to analyze the performance and dynamic response of driver/operator when subjected to different levels of vibration due to rough road conditions depicted in a mine field. The second purpose of the paper is to quantify the energy transmission in the presence of seat padding with special characteristics and active suspension. Using experimental testing data collected at NIOSH/PRL (National Institute for Occupational Safety and Health/ Pittsburgh Research Laboratory) along with model simulation algorithms developed at the University of Illinois at Chicago we investigated how acceleration transfer functions as well as absorbed power affects the different parts of the body. To this end, we used a previously validated human model which includes the head, torso segments and legs. The connective forces between body segments were modeled through modal analysis techniques from previous experimental data at the UIC Vehicle Technology Laboratory. The absorbed power and energy transmitted to the body are used as an index measure to assess the viability of the different seat padding’s and active seat suspension control strategies.


IEEE Transactions on Industry Applications | 1993

Mechanical sensor guidance of a mining machine

Christopher C. Jobes

Computer-assisted control of a mining machine can place the operator in a safe, remote location. A guidance system that aids in the remote positioning of a mining machine by determining its position and heading is described. The mechanical position and heading system (MPHS) developed at the US Bureau of Mines provides such navigation information during face maneuvers. Formulating the required theory yields a robust algorithm for calculating the position and heading. Implementing this theory through hardware and software design allows testing. Analysis of the errors and test results show that the MPHS provides reliable results. >


ASME 2016 International Mechanical Engineering Congress and Exposition | 2016

Performance Summary of Continuous Mining Machine Proximity Detection Systems

Peter T. Bissert; Joseph P. DuCarme; Jacob L. Carr; Christopher C. Jobes; Jeffrey Yonkey

Since 1984, remote controlled continuous mining machines (CMM) have caused 40 crushing and pinning fatalities in the United States. Due to limited space in the underground environment and visibility needs, CMM operators typically work close to the machine which exposes them to the danger of being struck or pinned by it. Because of these fatalities, the Mine Safety and Health Administration (MSHA) has published a rule requiring proximity detection systems (PDSs) on all CMMs except for full-face machines. To test PDS performance, researchers at the National Institute for Occupational Safety and Health (NIOSH) conducted a series of field tests in underground coal mines throughout the United States on CMMs equipped with PDSs. The field tests collected data under a variety of conditions to evaluate the warning and shutdown zone performance of these systems. A baseline test condition was measured when the machine was operating in non-mining mode. Three additional conditions discussed in this paper include testing of the PDS while the machine was operating in mining mode, examining the possibility of parasitic coupling to the trailing cable, and examining the effects of the presence of a shuttle car. The results of this study indicate that the average warning and stop zones vary minimally between non-mining mode and trailing cable influence measurements, as well as between the mining mode and shuttle car presence tests. A majority of the measurements for warning and stop zones showed repeatability within +/− 5 inches (12.7 cm). Additionally, parasitic coupling to the trailing cable was not experienced during this field testing. However, these results show that the range of stop zone measurements varied by 4.7 ft on average and as much as 11.7 ft in different field sites. This is most likely due to individual preferences by operators during installation when the warning and stop zone distances are set. While a PDS should effectively stop a CMM when an operator gets too close to the machine, the large variations between field test measurements indicate that there is a wide variation of performance established during system installation.


Proceedings of the Human Factors and Ergonomics Society Annual Meeting | 2013

A Visual Warning System for the Identification of Proximity Detection Events around a Continuous Mining Machine

Christopher C. Jobes; Jacob L. Carr; Miguel A. Reyes

Underground mobile mining machines pose a difficult safety challenge since their operators generally work in close proximity to these machines in very restricted spaces. Intelligent software for use with electromagnetic proximity detection systems has been developed that can accurately locate workers around mining machinery in real time. If a worker is located too close to the machine, the machine’s operation can be partially or completely disabled to protect the workers from striking, pinning, and entanglement hazards. Researchers have developed a visual method of relaying to the operators the interdiction of their machine operations by this intelligent proximity detection system. Several lighting sequence scenarios were human subject tested for effectiveness using a computer-based multimedia platform. Analysis of the test results indicates that a “fast flash” lighting arrangement is the most effective scenario based upon subject preference, rating, and accuracy of proximity intrusion location identification. This arrangement improves reaction time by 35%.


ieee industry applications society annual meeting | 2011

Determining proximity warning and action zones for a magnetic proximity detection system

Christopher C. Jobes; Jacob L. Carr; Joseph P. DuCarme; Justin Patts

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are developing intelligent software for use with electromagnetic proximity detection systems. The technology accurately locates workers around mining machines in real time. With the accurate locations of the workers around the equipment being known, their safety status can be evaluated. If a worker is located dangerously close to a machine, the machine can be partially or completely disabled to protect the worker from striking, pinning and entanglement hazards according to pre-defined logic. The technology is particularly applicable to mobile underground mining machines which offer difficult safety challenges in that operators generally work in close proximity to these machines in very restricted spaces. With use of the intelligent proximity detection system, nuisance alarms and failures to alarm are also expected to be sharply reduced. An effective proximity warning and action zone scheme is necessary for safe implementation and will improve the acceptance of a magnetic proximity detection system by underground workers.


International Journal of Industrial Ergonomics | 2008

Jarring/jolting exposure and musculoskeletal symptoms among farm equipment operators

Alan G. Mayton; N.K. Kittusamy; D.H. Ambrose; Christopher C. Jobes; M.L. Legault

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Alan G. Mayton

National Institute for Occupational Safety and Health

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Jacob L. Carr

National Institute for Occupational Safety and Health

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Farid Amirouche

University of Illinois at Chicago

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Jingcheng Li

National Institute for Occupational Safety and Health

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Joseph P. DuCarme

National Institute for Occupational Safety and Health

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N. Kumar Kittusamy

Centers for Disease Control and Prevention

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Peter T. Bissert

National Institute for Occupational Safety and Health

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Richard E. Miller

National Institute for Occupational Safety and Health

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Bertrand Valero

University of Illinois at Chicago

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Bingxi Li

Michigan Technological University

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