UnmannedSystemsTechnology.com interviews Ultra Motion to find out more about the unique attributes that make Ultra Motion actuators ideally suited for unmanned and robotic applications.
Ultra Motion is a leading developer of high-precision electro-mechanical servo actuators. Can you tell us why your products are so well suited to use within unmanned and robotic systems?
It ultimately comes down to experience and innovation. Ultra Motion has over thirty years of heritage designing actuators for the harsh environments found in spaceflight, aerospace, and deep-sea applications. All of the lessons learned in these applications have been distilled into a series of extremely robust processes and products that excel in demanding applications.
Our servo actuators all feature Ultra Motion’s patented Phase Index absolute position feedback and in-house brushless DC motor control electronics. By owning all aspects of the design, we are able to seamlessly integrate everything into the most compact and reliable actuator possible. Made in the USA, Ultra Motion actuators adhere to high-quality standards and are produced in quantities that can accommodate the needs of drone swarms and fleets.
We are constantly innovating to meet new industry demands like health monitoring, extended temperature ranges, increased power density, reduced backlash, and redundancy.
- Our CAN 2.0B protocol is compatible with the majority of commercially available autopilots and very easy to integrate with custom flight computers.
- We provide users with comprehensive telemetry via CAN and serial interfaces. This enables monitoring of various parameters including the actuator’s position, phase currents (which are proportional to output force), temperature, humidity, bus voltage, and overall health.
- The total accumulated travel of the actuator is stored in non-volatile memory, like an odometer, so that preventative maintenance procedures can be defined in critical applications
- Self-heating functionality allows for extended cold temperature operation
- Our new L-Series linear servo has zero axial backlash which allows for the increased vehicle control authority necessary for high speed and demanding applications.
- The L-Series is also available in a dual redundant configuration for applications requiring single electrical fault tolerance like swashplate actuation and critical payloads.
Can you outline the key advantages of Ultra Motion’s cutting-edge Phase Index non-contact position sensing technology and how it gives your products an edge in the unmanned sector?
In vehicle control applications, absolute position feedback is indispensable. Imagine a control surface needing to reset to a limit switch mid-flight due to an unexpected power cycle. Our Phase Index position sensor offers high resolution, batteryless, and contactless absolute position feedback within milliseconds of startup, all within an extremely compact and robust package.
Compared to conventional absolute solutions such as potentiometers, LVDTs, and absolute encoders, Phase Index boasts several advantages. It is immune to wear and extremely resistant to shock, vibration, electrical noise, and temperature fluctuations. Moreover, it imposes negligible impacts on the actuator’s size and mass.
For critical applications, dual or triple redundant versions of Phase Index are available, maintaining near-zero impact on size and mass. Further details >>
Thinking about the AM Series of heavily ruggedized servo cylinders, what applications are common for these actuators, and what design attributes make them appealing to customers?
Ultra Motion Servos are currently being used in a variety of uncrewed applications including:
- Control surfaces, fins, utility actuation, and landing gear on fixed-wing UAVs
- Swashplate and tail-rotor control of UAV rotorcrafts
- Rudder, jet-nozzle, and hydrofoil control of USVs
- Throttle, brake and transmission control of UGVs
- Hydroplanes, dive-planes, and sensor deployment of UUVs
- Thrust vector control of small orbital rocket engines
The AM is designed specifically for use in harsh shock, vibration, and liquid environments with D38999 connectors, conformally coated control electronics, potted/staked internals, all interfaces O-ring sealed, internal humidity control, and a fully conductive enclosure for EMI/EMC compliance. The rapid and accurate motion capabilities of the Servo Cylinder along with high peak force capability and environmental resistance make it an extremely attractive solution for dynamic vehicle control.
Ultra Motion has leveraged our experience with these applications to release several new products including a rotary servo and a high power density linear servo. The L2 Linear servo will have a dual redundant option that includes two motors, two controllers, and a triplicated version of Phase Index for applications requiring single electrical fault tolerance and increased reliability.
What are the challenges when designing and manufacturing actuators for marine and subsea applications such as ROVs, and how does the AU Series address these?
There are many marine applications, specifically with unmanned surface vehicles, where the actuators are not submerged but must withstand constant saltwater splashing and significant shock loads due to wave loading at high sea states. The biggest challenges in marine environments are ingress and corrosion protection, which we address through detailed design and process control.
The AM, AU, T-Series, and L-Series products feature high-pressure O-ring seals on all static ingress points. While this decision increases the manufacturing complexity and quality control requirements, an O-ring seal provides a significant improvement in ingress protection compared to a molded or liquid gasket. For corrosion protection, we use hard coat anodized aluminum, marine grade stainless steel alloys, and proper dissimilar material isolation for galvanic protection. Our process control includes a pressure test on every sealed actuator we manufacture to ensure proper integrity of the seals.
Preventing liquid ingress and corrosion with thoughtful seal design, material selection, and finishing goes a long way towards creating a reliable product, but it’s not always enough. Internal humidity control is often overlooked. The following application note highlights a custom molded desiccant used within the Servo Cylinder to ensure long-term reliable operation in marine environments and is a great example of how Ultra Motion goes the extra mile.
Reliable subsea electric actuation must address the hydrostatic pressure force trying to crush the actuator. Instead of designing an incredibly thick-walled enclosure that can withstand extremely high pressures, our AU actuators feature a pressure compensated oil-filled design. Filling the actuator with oil provides an incompressible fluid that works together with our built-in pressure compensator to minimize the pressure differential between the actuator and the environment.
This design minimizes the stress on our seals and allows the actuator to easily move against the immense pressures. Integrating the pressure compensator directly into the actuator eliminates the need for external tubing/components which reduces system complexity. The integrated motor controller is specially designed to tolerate the extreme pressures at 6000+ meters below sea.
What is your approach to customization and adaptation of your products to meet specific customer requirements, and do you have any examples of this in real-world use cases?
Custom modifications to standard products is a common occurrence at Ultra Motion. Our engineering team will work together with a customer to develop a specification, design a solution, and issue a custom revision-controlled part number. Typical modifications range from simple pinout or connector changes, to ground up designs to meet specific mounting, redundancy, and performance demands.
