Motion Control

A Phase-Changing Pendulum to Control Spherical Robots and Buoy Sensors

The pendulum adds new flexibility to motion control. NASA’s Jet Propulsion Laboratory, Pasadena, California A novel mechanical control system has been proposed for spherical robots to be used as multifunctioning sensor buoys in areas with ambient forces such as winds or currents. The phase-changing pendulum has been specifically designed for Moballs, a self-powered and controllable multifunctioning spherical sensor buoy to be used in the Arctic and Antarctica, or in other solar system planets or moons with atmosphere, such as Mars or Titan. The phase-changing pendulum has been designed to function in different phases: 1) When used as the spherical buoy, the Moball needs to take advantage of external forces such as the wind for its mobility. With no constraints, it could keep the center of mass in the geometric center of the sphere to facilitate the sphere’s movement. 2) However, as soon as the Moball needs to slow down or stop, the sphere’s center of mass can be lowered. 3) Furthermore, the phase-changing pendulum could lean to the sides, thereby changing the direction of the Moball by biasing its center of mass to the corresponding side. The Moballs could take advantage of such a novel phase-changing pendulum to go as fast as possible using the ambient winds, and to stop or steer away when facing hazardous objects or areas (such as the gullies), or when they need to stop in an area of interest in order to perform extensive tests. It is believed that this is the very first time that a pendulum has been suggested to control a spherical structure where both the length and the angle of the pendulum are adjustable in order to control the sphere. 4) Finally, the phase-changing pendulum could also control the sphere in the absence of wind. The spherical sensor buoys or Moballs could use the stored harvested energy (e.g., from sunlight or earlier wind-driven motions) to move the phase-changing pendulum and create torque, and make the spherical sensor buoys initiate rolling with the desired speed and direction. This is especially useful when the spheres need to get close to an object of interest in order to examine it.

Posted in: Articles, Briefs

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Computation of Wing Deflection and Slope from Measured Strain

Patent-pending methodology computes detailed wing loads during actual flight. Armstrong Flight Research Center, Edwards, California A lightweight, robust fiber-optic system is the technology behind a new method to compute wing deflection and slope from measured strain of an aircraft. This state-of-the-art sensor system is small, easy to install, and fast, and offers the first-ever means of obtaining real-time strain measurements that can accurately determine wing deflection and slope during flight. Such measurements are particularly useful for real-time virtual displays of wing motion, aircraft structural integrity monitoring, active drag reduction, active flexible motion control, and active loads alleviation.

Posted in: Articles, Briefs, Aviation, Measuring Instruments

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Enabling Microliquid Chromatography by Microbead Packing of Microchannels

The microbead packing is the critical element required in the success of onchip microfabrication of critical microfluidic components for in-situ analysis and detection of chiral amino acids. In order for microliquid chromatography to occur, there must be a stationary phase medium within the microchannel that interacts with the analytes present within flowing fluid. The stationary phase media are the microbeads packed by the process discussed in this work. The purpose of the microliquid chromatography is to provide a lightweight, low-volume, and lowpower element to separate amino acids and their chiral partners efficiently to understand better the origin of life.

Posted in: Imaging & Diagnostics, Materials / Adhesives / Coatings, Monitoring & Testing, Optics/Photonics, Bio-Medical, Briefs, TSP, Briefs, TSP, Diagnostics, Fluid Handling, Measuring Instruments

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Heart Pump with Behind-the-Ear Power Connector

One-third of patients with heart pumps develop infection at abdominal connection. Cardiac surgeons and cardiologists at the University of Maryland Heart Center are part of a multi-center clinical trial evaluating the efficacy of powering heart pumps through a skull-based connector behind the ear. The pumps, called left ventricular assist devices (LVADs), support the heart’s main pumping chamber, the left ventricle. LVADs are implanted in the chest and powered with external batteries. Typically, these devices, which are used for patients with severe heart failure, are powered through an electrical cord connected at the abdomen, where potentially deadly infections can develop.

Posted in: Drug Delivery & Dispensing, Electronics, Implants & Prosthetics, Bio-Medical, Briefs, Briefs, Electronic Components, Electronics, Power Management, Power Supplies, Implants & Prosthetics, Patient Monitoring, Fluid Handling, Power Transmission

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Compact, Low-Force, Low-Noise Linear Actuator

This actuator has potential uses in military and automotive applications. Actuators are critical to all the robotic and manipulation mechanisms that are used in current and future NASA missions, and are also needed for many other industrial, aeronautical, and space activities. There are many types of actuators that were designed to operate as linear or rotary motors, but there is still a need for low-force, low-noise linear actuators for specialized applications, and the disclosed mechanism addresses this need.

Posted in: Tech Briefs, Mechanics, Briefs

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Ultra-Compact Motor Controller

Applications include industrial robotic arms, industrial machinery, and automobiles. This invention is an electronically commutated brushless motor controller that incorporates Hall-array sensing in a small, 42-gram package that provides 4096 absolute counts per motor revolution position sensing. The unit is the size of a miniature hockey puck, and is a 44-pin male connector that provides many I/O channels, including CANbus, RS-232 communications, general-purpose analog and digital I/O (GPIO), analog and digital Hall inputs, DC power input (18–90 VDC, 0–l0 A), three-phase motor outputs, and a strain gauge amplifier.

Posted in: Tech Briefs, Mechanics, Briefs

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High-Accuracy Closed Loop Force Feedback

Benefits of serial servo digital presses for force gauge specifications. Hand-driven press assemblies, which require a specific amount of force applied for a given amount of time, present challenges when attempting to accurately measure or replicate results in production or quality control processes. In contrast, servo-driven digital presses are able to provide accurate, consistent, and repeatable results while outputting trackable data. By controlling position and current, the servo-driven digital press allows for stable, accurate, and repeatable control.

Posted in: Bio-Medical, Briefs, Briefs

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