Jeremy Newkirk

Measurement and quantification of gross human shoulder motion

The shoulder girdle plays an important role in the large pointing workspace that humans enjoy. The goal of this work was to characterize the human shoulder girdle motion in relation to the arm. The overall motion of the human shoulder girdle was characterized based on motion studies completed on test subjects during voluntary natural/unforced motion. The collected data from the experiments were used to develop surface fit equations that represent the position and orientation of the glenohumeral joint for a given humeral pointing direction. These equations completely quantify gross human shoulder girdle motion relative to the humerus. The equations are presented along with goodness-of-fit results that indicate the equations well approximate the motion of the human glenohumeral joint. This is the first time the motion has been quantified for the entire workspace, and the equations provide a reference against which to compare future work.

Design of a Humanoid Shoulder Complex Emulating Human Shoulder Girdle Motion Using the Minimum Number of Actuators

This paper describes a design for a humanoid shoulder complex that replicates human shoulder girdle motion. The goal here is to use the minimum number of actuators to keep the mechanism as light as possible to help ensure that a humanoid is not too top heavy. The human shoulder girdle has two degrees-of-freedom (DOF), which means the minimum number of actuators is also two. The proposed mechanism is a novel parallel platform with two DOF that acts as a pointing mechanism. As the mechanism is articulated the end-effector moves, which results in contraction or elongation, mimicking the natural motion of the human shoulder girdle. A parallel platform was chosen because of the inherent rigidity and a large workspace is not necessary. The mechanism presented here was chosen because of its simplicity and ability to track human shoulder girdle motion. Motion studies were conducted to collect data representing human shoulder girdle motion, which was used to optimize the mechanism for tracking human shoulder girdle motion as closely as possible. A second optimization was performed to ensure that the mechanism avoids singularities throughout its entire range of motion. The results show that this design closely replicates human shoulder girdle motion and is well-suited for use as a humanoid shoulder girdle to increase the range of motion for a humanoid arm.

StrapMaster: A robotic band-strapping system

This paper presents a robotic system that performs the steel-strapping process of coils for the metals industry. In the metal coil manufacturing plant, the packaging of coil-product is conventionally performed by dedicated machines specially designed for different strapping modes, such as outer circumference, eye-cross/parallel, vertical, horizontal or sheet pack. In most cases in the current industry, several of these mode-specific strap machines are serially lined-up in order to perform the required strapping sequence. We developed a self-contained robotic system consisting of a pair of 6-dof articulated arms, where the two arms are cooperating with each other to perform three different types of strapping modes. Compared to the conventional machine setup, this robotic solution reduced the floor space to 30% and reduced the equipment cost down to 65%, yet met the cycle-time requirement. The steel-coil strapping process is described, and the conventional and robot method are detailed and analyzed in a technical and economical perspective.