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NASA’s Mars Rover Required a Special Touch for Its Robotic Arms

ATI Industrial Automation brings its Force/Torque Sensor from the factory floor to the harsh environment of Mars’ surface.

3 min read
Mars_Rover_Sensor

In July, NASA launched the most sophisticated rover the agency has ever built: Perseverance. Scheduled to land on Mars in February 2021, Perseverance will be able to perform unique research into the history of microbial life on Mars in large part due to its robotic arms. To achieve this robotic capability, NASA needed to call upon innovation-driven contractors to make such an engineering feat a reality.

One of the company’s that NASA enlisted to help develop Perseverance was ATI Industrial Automation. NASA looked to have ATI adapt the company’s own Force/Torque Sensor to enable the robotic arm of Perseverance to operate in the environment of space. ATI Force/Torque sensors were initially developed to enable robots and automation systems to sense the forces applied while interacting with their environment in operating rooms or factory floors.

However, the environment of space presented unique engineering challenges for ATI’s Force/Torque Sensor. The extreme environment and the need for redundancy to ensure that any single failure wouldn’t compromise the sensor function were the key challenges the ATI engineers faced, according to Ian Stern, Force/Torque Sensor Product Manager at ATI.

“ATI’s biggest technical challenge was developing the process and equipment needed to perform the testing at the environmental limits,” said Stern. “The challenges start when you consider the loads that the sensor sees during the launch of the Atlas 5 rocket from earth. The large G forces cause the tooling on the end of the sensor to generate some of the highest loads that the sensor sees over its life.”

Once on Mars the sensor must be able to accurately and reliably measure force/torques in temperatures ranging from -110° to +70° Celsius (C). This presents several challenges because of how acutely temperature influences the accuracy of force measurement devices. To meet these demands, ATI developed the capability to calibrate the sensors at -110°C. “This required a lot of specialized equipment for achieving these temperatures while making it safe for our engineers to perform the calibration process,” added Stern.

In addition to the harsh environment, redundancy strategies are critical for a sensor technology on a space mission. While downtime on the factory floor can be costly, a component failure on Mars can render the entire mission worthless since there are no opportunities for repairs.

This need for a completely reliable product meant that ATI engineers had to develop their sensor so that it was capable of detecting failures in its

measurements as well as accurately measuring forces and torques should there be multiple failures on the measurement signals. ATI developed a patented process for achieving this mechanical and electrical redundancy.

All of this effort to engineer a sensor for NASA’s Mars mission may enable a whole new generation of space exploration, but it’s also paying immediate dividends for ATI’s more terrestrial efforts in robotic sensors.

“The development of a sensor for the temperatures on Mars has helped us to develop and refine our process of temperature compensation,” said Stern. “This has benefits on the factory floor in compensating for thermal effects from tooling or the environment.”

Stern points out as an example of these new temperature compensation strategies a solution that was developed to address the heat produced by the motor mounted to a tool changer. This heat flux can cause undesirable output on the Force/Torque data, according to Stern.

“As a result of the Mars Rover project we now have several different processes to apply on our standard industrial sensors to mitigate the effects of temperature change,” said Stern.

The redundancy requirements translated into a prototype of a Standalone Safety Rated Force/Torque sensor capable of meeting Performance Level d (PL-d) safety requirements.

This type of sensor can actively check its health and provide extremely high-resolution data allowing a large, 500 kilogram payload robot handling automotive body parts to safely detect if a human finger was pinched.

ATI is also leveraging the work it did for Perseverance to inform some of its ongoing space projects. One particular project is for a NASA Tech demo that is targeting a moon rover for 2023, a future mars rovers and potential mission to Europa that would use sensors for drilling into ice.

Stern added: “The fundamental capability that we developed for the Perseverance Rover is scalable to different environments and different payloads for nearly any space application.”

For more information on ATI Industrial Automation please click here.

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Economics Drives Ray-Gun Resurgence

Laser weapons, cheaper by the shot, should work well against drones and cruise missiles

4 min read
In an artist’s rendering, a truck is shown with five sets of wheels—two sets for the cab, the rest for the trailer—and a box on the top of the trailer, from which a red ray is projected on an angle, upward, ending in the silhouette of an airplane, which is being destroyed

Lockheed Martin's laser packs up to 300 kilowatts—enough to fry a drone or a plane.

Lockheed Martin

The technical challenge of missile defense has been compared with that of hitting a bullet with a bullet. Then there is the still tougher economic challenge of using an expensive interceptor to kill a cheaper target—like hitting a lead bullet with a golden one.

Maybe trouble and money could be saved by shooting down such targets with a laser. Once the system was designed, built, and paid for, the cost per shot would be low. Such considerations led planners at the Pentagon to seek a solution from Lockheed Martin, which has just delivered a 300-kilowatt laser to the U.S. Army. The new weapon combines the output of a large bundle of fiber lasers of varying frequencies to form a single beam of white light. This laser has been undergoing tests in the lab, and it should see its first field trials sometime in 2023. General Atomics, a military contractor in San Diego, is also developing a laser of this power for the Army based on what’s known as the distributed-gain design, which has a single aperture.

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