Small Business Innovation Research/Small Business Tech Transfer
Miniature 70-W Brushless Motor-Controller for Compact Extraterrestrial-Based Actuation
Project Description
This SBIR will support rover locomotion and manipulation with a system of newly-developed penny-sized 70-W brushless servomotor controllers that are networked on a bus-topology CANbus running CANopen. Each "P3" controller is small enough to be mounted in the tiny volume normally reserved for the encoder; and, indeed, each P3 carries the entire active electronics of the encoder function by measuring the magnetic field of a 6x2.5-mm radially-polarized button magnet bonded to the tail of the spinning motor shaft. A Kalman filter enables the encoder to read to 12-bits-absolute at commutated speeds up to 14,000 RPM. The controller has all of the functions expected of conventional controllers. However, based on three patents of international scope and a fourth PCT application, the part count has been substantially reduced, with subsequent reduced size, fewer parts to fail, fewer parts that otherwise generate quiescent power, and reduced cost. The Phase-I objectives will select two brushless servomotors of varying specifications that support NASA's rover missions. The electromechanical interface between P3 and the motors will be designed, assembled, fixtured with particle-brake loads, and then rigorously stress tested before working with NASA engineers to create a conceptual design for Phase II and beyond. Phase I is expected to result in a TRL of 4. Phase-II efforts will focus on design-modifications to address issues found in Phase-I and will encompass rigorous stress-testing in relevant environments. Phase II is expected to result in a TRL of 5. Phase-III commercialization efforts will create a system of motor controllers that not only support NASA rover missions, but also support other space-based non-terrestrial applications, such as servomotor actuation on satellites for precision antennae and laser pointing and the deployment of articulated structures.
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Anticipated Benefits
Brushless servomotors are essential in NASA applications such as mobile manipulation on rovers and for satellite navigation, control, and positioning where the motors must remain in active service indefinitely. Unlike stepper motors, they do not induce unwanted vibrations aboard sensitive spacecraft. And, unlike brushed motors, brushless servomotors have high torque density, add no brush friction, do not generate contaminating dust, and have much longer life times. The use of brushless motors usually requires custom and expensive electronics that are often larger than the motors they control. This is especially true for small motors that operate below 100 watts. Frequently, the power required for the controller itself is greater than the power needed at the motor. One Fortune-100 customer is interested in purchasing initial sample units, but if technically successful, they would become a regular customer of a commercial version of the P3, thereby making these devices commercially available to NASA as affordable common-off-the-shelf (COTS) components.
As machines become more intelligent through embedded processing and sensor fusion we expect them to do more too, improving not only industrial productivity, but our quality of life as society ages. While embedded processors and MEMS-based sensors have become tiny, highly effective, and affordable; similar improvements in servomotors have evolved more slowly. At fractional-horsepower levels the power electronics contribute significantly to total motor-system bulk and complexity. Providing smaller and more efficient servoelectronics will enable OEMs to increase the competitiveness of their products. For example, robots will become more agile with additional degrees of freedom and less mass to accelerate. New fuel-cell designs combined with ultra-high motor efficiency will enable affordable prostheses with true dexterity instead of 0 or 1 degree of freedom; and orthotics will begin to assist human motions intelligently, rather than passively bracing. More »
As machines become more intelligent through embedded processing and sensor fusion we expect them to do more too, improving not only industrial productivity, but our quality of life as society ages. While embedded processors and MEMS-based sensors have become tiny, highly effective, and affordable; similar improvements in servomotors have evolved more slowly. At fractional-horsepower levels the power electronics contribute significantly to total motor-system bulk and complexity. Providing smaller and more efficient servoelectronics will enable OEMs to increase the competitiveness of their products. For example, robots will become more agile with additional degrees of freedom and less mass to accelerate. New fuel-cell designs combined with ultra-high motor efficiency will enable affordable prostheses with true dexterity instead of 0 or 1 degree of freedom; and orthotics will begin to assist human motions intelligently, rather than passively bracing. More »
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Primary U.S. Work Locations and Key Partners
| Organizations Performing Work | Role | Type | Location |
|---|---|---|---|
| Barrett Technology, LLC | Lead Organization |
Industry
Small Disadvantaged Business (SDB)
|
Newton, Massachusetts |
| Jet Propulsion Laboratory (JPL) | Supporting Organization | FFRDC/UARC | Pasadena, California |
Primary U.S. Work Locations
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California
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Massachusetts
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