Philip A. Voglewede

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Although cable-driven robots and parallel manipulators have very similar architecture, the presence of the unidirectional constraints in cable-driven robots makes it impossible to apply many of the concepts and methods used for parallel manipulators. Instead many tools from grasping are more suitable, since fingers also provide unidirectional constraints.(More)
Singular configurations where a parallel manipulator can lose stiffness are well documented and studied in literature. There exist many proposed measures on how close a pose is to these singularities. This paper develops a framework which unites many of the existing measures, provides further understanding for others, and creates new ones. The framework(More)
This short paper outlines how polynomial chaos theory (PCT) can be utilized for manipulator dynamic analysis and controller design in a 4-DOF selective compliance assembly robot-arm-type manipulator with variation in both the link masses and payload. It includes a simple linear control algorithm into the formulation to show the capability of the PCT(More)
Cable-driven robots and multifinger grasps are closely related to each other by the fact that both systems can provide unidirectional forces to the object to be constrained. While prior research primarily related cable-driven robots to grasps without friction, this article seeks to establish relationships between certain cable-driven robots and grasps with(More)
This paper outlines the design and testing of a powered ankle prosthesis, which utilizes a four-bar mechanism in conjunction with a spring and motor that mimics nonamputee (normal) ankle moments. This approach would enable transtibial (below the knee) amputees to walk at a normal speed with minimal energy input. The design takes into account the energy(More)
OBJECTIVE Powered robotic prostheses create a need for natural-feeling user interfaces and robust control schemes. Here, we examined the ability of a nonlinear autoregressive model to continuously map the kinematics of a transtibial prosthesis and electromyographic (EMG) activity recorded within socket to the future estimates of the prosthetic ankle angle(More)
It is well known that physical inactivity leads to loss of muscle mass, but it also causes bone loss. Mechanistically, osteoclastogenesis and bone resorption have recently been shown to be regulated by vibration. However, the underlying mechanism behind the inhibition of osteoclast formation is yet unknown. Therefore, we investigated whether mechanical(More)
Singularities of parallel manipulators cause severe problems in the use of such manipulators. Likewise, finding how close the manipulator is to a singularity is key to its operation. This article outlines a new method to define "closeness" to singularities based on constrained optimization and its resulting general eigenvalue problem. This framework joins(More)
A t a singular configuration the end-eflector of a parallel mmipu la tor m a y become underconstrained, i.e. instantaneous motion m a y become possible. The unconstrained EE motion mray be only instantaneous, or it can result in finite motion, also known as selfmotion. This article presents two diifferent approaches to analyze the potential f o r large mo t(More)
A powered ankle-foot prothesis and its control system were previously designed and built. To evaluate this prosthesis, amputee subject testing was performed. The testing results are analyzed and compared between the powered prosthesis, passive prosthesis, and able-bodied gait. Qualitative comparison showed the prosthesis achieved the design objectives.(More)
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