A Soft Multiple-Degree of Freedom Load Cell Based on The Hall Effect

The goal of this thesis is to develop a soft multiple-degree-of-freedom (multi-DOF) load cell that is robust and light weight for use in robotics applications to sense three axes of force and a single axis of torque. The displacement of the magnet within the elastomer changes the magnetic flux density which is sensed by two 3-axis Hall effect sensors. Experimental measurements of magnetic flux density within the area of interest were used to formulate analytic expressions that relate magnet field strength to the position of the magnet. The displacement and orientation measurement and the material properties of the elastomer are used to calibrate and calculate the applied load. The ability to measure 3-DOF force and axial torque was evaluated with combined loading applied by a robotic arm (KUKA, LBR r820 iiwa). The decoupled results show the 4-DOF load cell was able to distinguish 3-axis force and 1-axis torque with 6.9% averaged error for normal force, 4.3% and 2.6% for shear force in the X and Y axis and 8.6% for the torque. The results show good accuracy for a soft multi-axis sensor that would be applicable in many robotic applications where high accuracy is not required

Decision-making tool for incorporating cradle-to-gate sustainability measures into pavement design

Pavements consume large amounts of energy, materials, and a significant portion of maintenance funds, which cause a substantial strain on the environment and the economy. Hence, a sound framework for designing and constructing a sustainable pavement is needed. To measure sustainability in a pavement, various tools were developed and adopted. Among these approaches, life cycle assessment (LCA) is a widely used quantitative method for measuring the environmental impacts of pavement alternatives. However, application of LCA in pavement is challenging, as it requires substantial time and resources to collect the required data for the analysis. An alternative sustainability tool, environment product declaration (EPD), addresses some of the limitations of LCA. This study presents a cradle-to-gate framework for selection of a pavement design, based on optimization of the pavement mix design/products for structural, environmental, and economic performances. The developed framework allows one to compare different design/product alternatives that balance engineering goals against environmental and economic performances and combines the two into an overall performance score, which identifies a cost-effective and environmentally preferred pavement. This approach is inclusive of (1) an EPD analysis, which quantifies the environmental impacts from raw materials extraction to manufacturing; (2) a transportation analysis, which quantifies the impact of transporting mixes from a plant location to the construction site; and (3) an economic analysis, which evaluates the economic value of an alternative. Developed modules and databases were incorporated into a simple decision-making tool, aWindows-based software, which was developed for the selection of a design/product with a balance that extends across engineering, environmental, and economic performance criteria. The developed methodology is demonstrated in a number of case studies