This page presents some snippets of current and recent projects. See the Research page for a broader overview of my research activities.
Digital human modeling for ergonomics applications is the focus of my research in the Center for Ergonomics. The research I direct in the Human Motion Simulation Laboratory focuses on the development of algorithms and models for accurate prediction of human postures and motions in tasksituations relevant to product and workspace design. We emphasize algorithms that can be implemented in any human figure model, rather than limiting ourselves to the capabilities of one model. We are fortunate to have the developers of the two most popular software systems for industrial ergonomics (Dassault Systemes and Siemens PLM) engaged in our laboratory as technology partners. Among other topics, we're currently working on improving grasp simulation. The literature on grasp is vast, including contributions from motor control and robotics as well as ergonomics and human modeling. Yet, ergonomics using human models spend a large amount of time working to simulate grasp, often with poor results. As part of ongoing research in the Human Motion Simulation Lab, Ph.D. candidate Wei Zhou and I developed a data-based method for predicting grasp motions. The hand motions are parameterized on target size and grasp type, so that they're readily configurable for different objects. We integrated this kinematic prediction with collision sensing to enable automated grasp of objects with arbitrary geometry.
Three-dimensional anthropometry is a part of many of my current research projects. Using data from UMTRI's whole-body laser scanner, medical imaging data, or studies conducted elsewhere, we create statistical models of anatomical shapes. These models are used for a wide variety of design and analysis purposes, from creating anthropometric specifications for crash dummies to virtual seat assessments. One challenge in using 3D scan data is that each scan represents a single posture. For general applications, it's necessary to be able to alter the posture of the scan. This figure shows a statistical model of the seated torso that encompasses both anthropometric and postural variability. A single relaxed seated scan from each of 712 men and women was morphed to 15 different postures using a skeletal linkage. The resulting external body shapes were analyzed using a principal component analysis/regression (PCAR) approach to produce the model demonstrated in the figure. The model provides an efficient way of representing a wide range of seated body shapes driven by both structural anthropometry and posture.The model has applications from seat and chair design to the development of parametric finite-element models for crash safety analysis.
The design of truck and off-highway equipment cabs (agriculture, construction, mining, and forestry) is becoming more complex due to the increase in the use of electronic controls and displays. In most cases, the new equipment is added to the customary manual controls, creating a need to optimize the layout for all tasks.
We conducted a study of seated operators to quantify reach and force-exertion capability as a function of task location relative to the driver and package. Licensed truck drivers reached for push-button targets located throughout the workspace, providing subjective ratings of difficulty for each target. The subjects also exerted force on a handle located in 13 discrete positions spanning the range of typical hand control locations.
The drivers also operated accelerator, brake, and clutch pedals, using both normal motion speed and "as fast as possible", simulating emergency operation. An optical motion-capture system was used to record whole-body kinematics.
The data from this study are being used to develop new design tools for assessing and laying out truck and heavy equipment cabs.
Truck driving is among the most dangerous occupations in the U.S. Crashes are not the main cause of injury, though: Most occupational injuries to truck drivers are due to slips and falls. With support from at R01 grant from the National Institute for Occupational Safety and Health, we are conducting a field and laboratory study of truck driver ingress and egress. Our work uses biomechanical analysis techniques to quantify ingress/egress behaviors. We have gathered field data on entry and exit techniques drivers use, interviewed drivers on their experiences, and conducted a detailed laboratory study. Using an optical motion capture system and an instrumented cab mockup, we recorded driver's movements and the forces they exerted with a wide range of step and handhold configurations.
The outcomes of this research will include new design guidelines for truck ingress/egress systems (steps and handholds), new biomechanical analysis methodologies that can be used to assess candidate systems, and a better understanding of the factors that influence the risk to drivers of both acute and chronic injury.
The performance of belt-positioning booster seats used by children who are too small to achieve good belt fit with vehicle belts alone, and no longer riding in harness restraints, is assessed in U.S. regulatory tests using Hybrid-III dummies. Unfortunately, these dummies interact with belt restraints in unrealistic ways. The lap, shoulder, and chest areas where the belt contacts the dummy are of particular concern, because the dummy geometry in these areas is substantial different from the skeletal anatomy of similar-size children. We are working on developing improved components for the dummies, starting with the Hybrid-III six-year-old. We have developed new methods for extracting and analyzing the shapes of anatomical structures from medical imaging data. We've used these methods to create a statistical model of the child pelvis, thorax, and shoulder based on data from over 80 children from ages 4 to 12. The analysis allows us to create skeletal models for children in that age range as a function of age, stature, body weight, or other variables. We've used these model to create a geometric target for the 6YO pelvis and thorax. This figure compares the skeletal gometry of the Hybrid-III 6YO to the targets.
The National Highway Traffic Safety Administration (NHTSA) has amended Federal Motor Vehicle Safety Standard (FMVSS) 202 to require higher and more-forward head restraints (sometimes called head rests, but primarily intended to protect occupant's necks in rear collisions). The new regulation, called FMVSS 202a, requires that head restraints lie within 55 mm of a Head Restraint Measurement Device representing a midsize-male head shape when measured at a seat back angle of 25 degrees. When this rule was proposed, my colleagues and I published a report showing that most drivers sit with more-upright seatback angles. We concluded that designing to the 55-mm "backset" would cause the head restraint to interfere with the preferred head locations of a substantial number of drivers. This prediction has since been substantiated by other research and field reports from vehicles built to the new standard. Recently, my colleague Prof. Matt Parkinson, who heads the OPEN Design Laboratory at Pensylvania State University, conducted a simulation study of an alternative seat back design that optimizes the head restraint position across seat back angles. This approach reduces the likelihood of interference with the head restraint for smaller-stature drivers while ensuring that taller drivers, who tend to select more-reclined seat back angles, are equally well protected. More...
©2013 Matthew P. Reed and The University of Michigan