Precision Low Speed Motor Controller

Satellites and other spacecraft require maintenance and service after being deployed in orbit, requiring a wide variety of tools that perform multiple maintenance tasks (grip, cut, refuel, etc.). Current drive systems for the tool interfaces on the robotic arms that perform these service tasks are not as robust nor packaged properly for use in the ATDS. The ATDS is one part of a larger in-space servicing system (example shown in the figure below) that must be versatile and perform multiple jobs. Here, innovators at the NASA Goddard Space Flight Center have developed new BLDC motors to provide the torque necessary to drive the wide variety of tools needed for in-space servicing. The four motors provide torque to the coupler drive, linear drive, inner rotary drive, and outer rotary drive of the ATDS. The new BLDC motors will enable the tools attached to the ATDS to be operated in multiple modes of operation. Each of the four motors have been customized with different speed and torque capabilities to meet the different performance requirements of the various actuator drive trains while maintaining a common gearhead across all the motors. Further, the packaging surrounding the motors has been tailored to reduce the overall weight of the motors and reduce the motor footprint to meet the needs of the ATDS. The BLDC motors for the ATDS are available for patent licensing.

The Foot Pedal Controller enables an operator of a spacecraft, aircraft, or watercraft, or a simulation of one in a video game, to control all translational and rotational movement using two foot pedals. This novel technology allows control across all six degrees of freedom, unlike any technology on the market. The components of the technology are a support structure, a left foot pedal, a right foot pedal, and supporting electronics. The Foot Pedal Controller is intuitive, easy to learn, and has ergonomic features that accommodate and stabilize the operator's feet. A working prototype is available to demonstrate key technology features to potential licensees. The Foot Pedal Controller technology could be used in designs for the flight deck of the future, video game controls, drone operations and flight simulators. This technology can be useful in any application where it is preferred or desirable to use the feet to control motion rather than using the hands. A potential market could be foot control of equipment by people with arm or hand disabilities. A unique aspect of the innovation is the consideration of natural foot mechanics in the design and placement of the sensors and actuators to reduce operator fatigue. The axes of rotation of the Controller align with the joints of the foot so the foot moves naturally to control the movement of the craft. NASA seeks collaborations with companies interested in licensing and partnering to further develop and commercialize the technology.

The traditional scissor spring design for hand controllers has been improved upon with a circumferential spring controller mechanism that facilitates easy customization, enhanced durability, and optimum controller feedback. These advantages are partially facilitated by locating the spring to the outside of the mechanism which allows for easier spring replacement to adjust the deflection force or for maintenance. The new mechanism is comprised of two rounded blades, or cams, that pivot forward and back under operation and meet to form a circle. An expansion spring is looped around the blade perimeter and resides in a channel, providing the restoring force that returns the control stick to a neutral position. Due to the use of a longer circumferential spring, the proportion of spring expansion is smaller for a given distance of deflection, so the forces associated with the deflection remain on a more linear portion of the force deflection curve. The Circumferential Scissor Spring for Controllers is at technology readiness level (TRL) 8 (actual system completed and flight qualified through test and demonstration) and is available for patent licensing. Please note that NASA does not manufacture products itself for commercial sale.

The Modular Robotic Vehicle (MRV) is a vehicle designed for transportation in congested areas. The MRV is relatively small, easy to maneuver and park. The MRV was designed without a central power plant, transmission, fuel tank, and direct mechanical linkages between driver input devices and the actuators used to accelerate, brake and/or steer the car. These core vehicle functions are located at the corners of the vehicle in a modular electric corner assembly or eCorner. Because the MRV uses a by-wire control system, substantial space and weight is conserved compared to conventional designs. Moreover, the functional capabilities that are provided by the individual eCorners enable control of the vehicle in a variety of different operating modes. The eCorners provide significant flexibility in driving options. For example, the driving mode can be switched so that all four wheels point and move in the same direction achieving an omni-directional motion or all wheels can be pointed perpendicular to the center of the vehicle allowing rotation around its center axis. This mode makes some driving maneuvers like parallel parking as easy as driving next to the spot, turning the wheels 90 degrees, and driving into the open spot in a sideways motion. Each eCorner includes its own redundancy to protect for electrical failures within the systems. The driver can choose to control the vehicle with a conventional steering wheel or add inputs through a multi-axis joystick for additional control in some of the more advanced drive modes. The vehicle has the propulsion motors located inside of each eCorner with the capability of producing 190 ft-lbs of torque with a current top speed of 40 mph. An active thermal control loop maintains the temperatures of these high powered motors and a separate thermal loop cools the avionics and the custom lithium-ion battery packs. The linked vehicles are able to exchange or share control data and electrical power. Finally, the MRV has remote driving control capability.

Electrically driven turbine engine compressor and propulsion fans require a large stability margin against stall conditions to avoid unwanted performance issues while undergoing transients in operating conditions. This stability margin, while it maintains safe operation, also necessarily reduces the engine performance. Despite extensive research efforts, no viable alternative methods for reducing the operable stability margin and improving engine performance exist. This current innovation, originally conceived for stall prevention, offers a solution by utilizing a supercapacitor in line with an electric motor and motor controller to rapidly change a compressor or propulsor fan speed. The use of the supercapacitor enables rapid extraction, or addition of power, to prevent the fan from stalling. Additionally, this novel drive motor may be used for sensing stall event precursor signals by using the motor controller to detect variations in torque on the shaft caused by variance in loading on the blade system. The improved stall avoidance capabilities allow an engine fan to operate more efficiently, providing more thrust for a given frontal area, increasing operational range, reduced weight, and improved operational safety. The related patent is now available to license. Please note that NASA does not manufacture products itself for commercial sale.