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Design of Innovative Machines Lab

Shape-Changing Rigid Body Mechanisms

Many design problems are defined by a curve that changes shape. Consider the profile of a wing during a flight where lift may be reduced as fuel burns off, or a spoiler where the downward force should be increased during cornering. As the spoiler and the wing should always have a shape that is spoiler-like or wing-like as it is changing, all of the interim shapes achievable by the mechanism should still define a usable spoiler or wing. The research on this project is identifying the underlying theory that allows these systems to be designed, and developing application specific technologies.

Shape-Changing Extrusion Dies

The DIMLab team is working to incorporate its shape-changing research into the field of die design. Polymer extrusion is the manufacturing process of utilizing pressure to force melted plastic through a die in order to form a long part of uniform cross section. The shape of the die defines the extruded product’s cross section. Extrusion is used to create a variety of products including tubes, pipes, gutters and molding. This process has always been achieved using solid, non-deformable dies. Shape-changing dies allow the cross section of the extrusion to change while being forced through the die. This technology offers three advances. First, new and innovative products can be developed. Second, this technology introduces the capacity to manufacture parts previously obtainable through slower and more costly techniques like molding. Third, this technology reduces waste in extrusion processes by allowing the implementation of tunable dies. Some of the design challenges facing the research team include addressing the high pressures and temperatures present in extrusion die systems, minimizing material leakage in the die assembly, and creating the methodology and practice for designing dies that create the desired shape changes in the extrusion.

Novel Devices Utilizing Strain-Energy in Automobiles
The team is currently working with General Motors Research (located in Warren, Michigan) to develop two new devices that reduce the negative environmental impact of automobiles. The first of these two devices is a mechanical regenerative brake and launch-assist. During braking, the device stretches a spring to store the kinetic energy of the vehicle. The launch-assist comes when the stretched spring releases its energy to accelerate the vehicle.

Statically Equivalent Serial Chains

This project was initiated while Murray worked with Philippe Fraisse and Sebastien Cotton of The Montpellier Laboratory of Informatics, Robotics, and Microelectronics,in Montpellier, France. The work, now continuing with Dr. Raul Ordonez of University of Dayton's Department of Electrical and Computer Engineering, has the goal of identifying the kinematic, static and dynamic properties of an articulated system with procedures that are as unobtrusive as possible. That is, can we develop an accurate model of someone simply by filming them or having them perform a few simple activities? With the goal of sizing the next generation of human-centric exoskeletons or personal flying devices, these accurate models will be critical. Visit the research page of Philippe Fraisse (of LIRMM).

University of Dayton School of Engineering DIMLab Hoap

Design of Machines for Energy Reduction in Controlled Motions
Where do you choose to stand, and in what pose, when performing the task of moving a heavy box? You could stand in a variety of different locations and poses, and some are definitely better than others. How would your pose and standing location change if you doubled the length of your arms? How would they change if you had a third arm? Finally, which of these choices results in you using the least among of energy to move the heavy box? Now change the problem to one of machine design. This research seeks to identify the principles by which mechanisms should be configured and positions in order to minimize the amount of energy used to perform these highly repetitive actions.
Design of Coupler-Drivers
History has put mechanism design at a disadvantage. Typically, the pieces of a device are sized to accomplish a task, and then an actuator is attached to one of the joints in the device. This is far from ideal as the joints are located to make the device move in the right way, but not necessarily to provide the ideal point from which to make the motion happen. This research seeks to introduce a simple actuating chain into the design process that allows the designer the capacity to design a device for the best motion, and then design the actuation scheme to produce the most desirable drivers for that motion. This research has particular application for pick and place devices.
Part-Orienting Devices
A POD, Part Orienting Device, is a low degree-of-freedom machine capable of producing spatial trajectories and rotations. A single “part orienting device”, or POD, can be used in a task that might otherwise require a robot or multiple single degree-of-freedom mechanisms. A simple example of a POD might be a robot wrist customed design to for a single operation that needs to be performed thousands or millions of times. Such a wrist could be faster, more accurate, and operate with significantly lower energy requirements than a traditional robot wrist.
Transition Linkage Identification
The team is developing techniques for identifying mechanisms that, through a simple change to one of its parameters, exhibit striking changes in behavior. A simple parameter change includes something as minor as taking a single dimension in the mechanism and changing it by a few percent. The challenge of this work is that it quickly generates large systems of polynomials that can only be solved numerically. In fact, the plot to the right shows one of the curves described by the systems of polynomials indicative of this research. Early work in this area generated a software design award for Murray and Herb Stumph, his graduate student at the time. This work now continues with Dr. Charles Wampler, a Technical Fellow at the General Motors Research and Development Center, and an expert on manipulating and solving systems of algebraic polynomials.
CONTACT

DIMLab, Dr. Andrew Murray and Dr. Dave Myszka, Directors

Fitz Hall
300 College Park
Dayton, Ohio 45469
937-229-5350