Author Archives: Cody Belichesky

Five Reasons Why ThinGap Is A RWA/CMG Motor Leader

From aerospace to motorsports, many industries rely on ThinGap’s cogless motor technology. One of the largest applications for ThinGap’s patented motor technology has been active control systems for satellites. Satellites of all sizes require the ability to control their orientation in orbit, what is referred to as “Attitude Control.”  Whether commercial or defense in nature, LEO spacecrafts need Attitude Control that enables high accuracy pointing capabilities so that desired objects of interest, point-to-point communication or optical platforms can be effectively utilized.

Active control systems, such as Reaction Wheels Assemblies (RWA) and Control Moment Gyroscopes (CMG), require highly efficient motors for torque and actuation. With two lines of high performance slotless motors — both with space heritage, ThinGap’s cogless motor technology is well suited for these Attitude Control solutions.

Here are the top five reasons why ThinGap is the industry leader for RWA and CMG motors.

  1. HIGH EFFICIENCY | For reaction wheel motors, ThinGap supplies ironless or “air core” stators made of fine stranded wire for the coil. This lends itself to very low drag at high operating speeds, with a significant improvement over traditional iron core slotted motors. Additionally, the torque capacity is increased across the full operating range for the same momentum storage capacity.
  2. HIGH TORQUE AND INERTIA-TO-WEIGHT RATIOS | ThinGap’s ironless stator puts all the magnetics, the heaviest part of the motor, in the rotor. This maximizes the inertia for a given weight and size requirement. The reaction wheel’s necessary flywheel mass can be reduced, and sometimes fully incorporated into the rotor. The resulting package is lighter weight for the same momentum storage capacity.
  3. HIGH PRECISION | ThinGap’s motors use a wave-wound coil, which results in a back EMF that is sinusoidal with a total harmonic distortion of less than 1%. When paired with a sinusoidal drive, torque ripple is minimized and much lower than similar motors. Additionally, the ironless stator produces absolutely zero cogging motion. In combination, these aspects produce the highest precision RWA motor available.
  4. DYNAMIC RESPONSE | Due to no iron saturation in the stator, ThinGap’s peak torque capacity is much higher for a similar weight motor. This gives a dynamic response significantly better than the competition at a lighter weight.
  5. COMPLIANCE AND CAPABILITY | ThinGap designs and builds its motors in the USA and provides highly engineered solutions and program support. Since 2015, thousands of Space-grade or MIL-STD rated motor parts have shipped for use in commercial satellites, UAVs, military aircraft, and NASA flight programs.

The TG Series‘ and TGR Series‘ high-speed, high-efficiency is ideal for momentum-wheels in both RWA and CMG. The LS Series’ high-torque, lower-speed precision movement is perfect for gimbal applications, like those in a CMG architecture and related Satcom and Optical applications.

Since 2015, ThinGap has shipped thousands of space-grade or MIL-STD rated motor parts for use in commercial satellites, UAV, military and commercial aircraft, and flight-grade NASA programs.

ThinGap’s Motor Tech Covered By Partner Sierramotion

ThinGap’s motor technology has been covered in a very informative article by our close business partner Sierramotion entitled “DIRECT DRIVE – AN ENGINEER’S GUIDE”.

The Applications Team at Sierramotion recently posted a blog on their company’s website where they outlined the desired motor performance in Direct Drive applications, focusing on characteristics such as zero-cogging, and large internal diameter.  While ThinGap was not mentioned by name (no vendors were), an image of the LS Series slotless motor kit was prominently shown.

One interesting excerpt from the post related to motors is sited below:

“The accurate definition of a motor has to do with its mechanism for generating torque or force and how many electromagnetic phases it has and how they are controlled/commutated. Electromagnetic (EM) torque/force production is derived from an interaction between two magnetic fields or through a change in reluctance or permeance with position/angle, (or some combination of these two main groups). There are four main electromagnetic motor types in use today; brush commutated DC or AC motors, electronically commutated Synchronous Permanent Magnet Motors (AKA Brushless DC), AC Induction Motors (AKA Asynchronous), and electronically commutated Variable Reluctance (AKA Switched Reluctance). Of course, there are hybrid combinations of these technologies also in use. There aren’t any new forms of EM torque generation, in spite of what you may read on the internet.”

To read the complete Sierramotion post, click here

How Gimbals Work

One of the largest use-cases for ThinGap’s slotless motors are Gimbals, so much so that it considers itself to be the performance leader in Gimbal motors. From handheld applications for action cameras to large platforms designed for satellite-to-satellite communication, the applications of gimbals are endless. By using an array of different sensors and motors to counteract movement, electrically controlled gimbals serve to keep platforms stable and focused.

The three forces that gimbals are designed to counteract are tilt and pan (directional horizontal rotation), and roll (vertical rotation). These three axes of movement are counteracted by the sensors and electric motors that work to counteract the forces enacted on the platform. No matter the orientation, whatever is on the platform is held stable and even. By counteracting the forces of gravity with brushless electric motors, orientation can be held indefinitely (within reason). In the world of airborne and space Gimbals, three-axis refer to the angular movement as being Azimuth, Elevation, and Roll.


Image Credit: ResearchGate

In large systems, such as Turrets, the inner design works as a Gimbal allowing for control over roll movement and can be used in aircraft and satellites. On aircraft, optical platforms such as infrared, visible light, and lasers can be mounted on a Gimbal platform that is then fixed to a turret and placed within a fairing to protect it from aerodynamic forces.

Satellites use Gimbals for communication in a similar method for pointing and positioning, with the gimbals acting as the turret and gimbal unit alone, and a device called a fast-steering mirror delivering fine precision control that ensures a reliable optical data connection between satellites, either between low Earth orbit and geostationary satellites and between low Earth orbit satellites. This communication is conducted through pulses of laser light that transmit digital data in a similar manner to Morse Code used by telegraphs of the 19th century but in a far faster manner.


Image Credit: JAXA

What makes ThinGap motors ideal for Gimbal applications is the unique motor architecture that provides smooth movement. This smooth movement is zero-cogging which is afforded by ThinGap’s patented method for distributing stator coil wire windings within a thin cross section that eliminates traditional stator teeth, resulting in a motor without cogging torque.

Cogging is an unwanted magnetic torque disturbance caused by the winding patterns around the stator’s iron teeth that are the basis of “slotted” motors. Slotless motors eliminate cogging torque and offer smooth motion that is critical to optical systems for precision aiming, point and zooming at long standoff distances, and smooth motion for precise scanning.

ThinGap’s line of slotless motor kits feature high-performance, zero-cogging, high efficiency, and a lightweight design. The motor kits are ideal for smooth and precise motion. The entire LS Series offers a large through-hole and a low-profile form factor, ideal for integration into a wide range of different platforms. LS motors offer torque performance equivalent to traditional frameless motor kits available on the market, but unlike other slotless motor solutions, does not require a trade-off between torque output and smoothness.

New LSO Series of “Out-Runner” Motor Kits Now Available

ThinGap has made available two new variants of its successful LS Series of torque motor products: the LSO 225-51 and LSO 225-66. The new parts are 225 mm wide and either 51 or 66 mm tall, respectively. Using an outrunner architecture (where the rotor revolves on the outside, as opposed to the inside of the stator), the new motor kits offer a mechanical feature that is beneficial to applications needing outside rotation around a stationary center. Prior custom LSO models have been developed for use in gimbals and satellite-based laser communication systems.

Like other ThinGap motors, these outrunner motors provide the same cogless motion, high torque output and overall efficiency as the in-runner line of LS motor kits. As an example, the LSO 225-66’s continuous torque of 17.86 N-m and 1.315 N-m/√W motor constant. They also offer a stator with a thin radial cross-section and optimized permanent-magnet rotor. This results in a large aperture while being weight-optimized and low profile. The LSO 225-51 has a part set mass of just 2.4 kg and a 198 mm through hole, representing 88% of the part’s outer diameter (OD).

The LS Series of frameless motor has been built by ThinGap over the last five years and now offers more than 20 different models. They range in size from 25 mm up to 267 mm OD, and numerous axial heights, all providing highly scalable power and torque outputs.
Along with the two new LSO products detailed herein, the existing line of LS motors are in-runner types, as denoted by the product prefix of “LSI”.

ThinGap expects to release additional sizes to build out the LSO product line in 2022.

ThinGap Participates in the 36th Space Symposium

ThinGap participated in the 36th Space Symposium in Colorado Springs on August 24-26, 2021. The company was represented at the show by its CEO, John Baumann and Matt Panesis, its lead Applications Engineer. Additional members of ThinGap network of sales representatives were present at the show. In addition to meeting potential customers, domestic and international Space agencies, and industry partners, ThinGap proudly demonstrated a working unit of its recently released H-LSI 75-12, a turnkey Direct Drive Motor Assembly based on the company’s slotless motor technology.

John Baumann, ThinGap’s CEO, commented on the event, “After the last year and a half, it’s great to be back out on the road and meeting with customers, especially those in the critical Space sector. It was beneficial to not only meet with our customers and the Government sponsors, but also to network with industry partners and would-be collaborators.”

ThinGap slotless motors are widely used in many space applications, including Reaction Wheels, Control Moment Gyroscopes, Gimbals, Point-and-Track SATCOM, Pumps and other precision actuation functions need in satellites and spacecraft. For vacuum-compatible motor kits, ThinGap will provide a custom variant of its commercial off-the-shelf motor. With these modifications, the motor kits can address the need for various program specifications, including low outgassing materials, specialty electronics, and in some cases, redundant stator windings to provide mission-critical assurance.

Space Symposium, held at The Broadmoor in Colorado Springs, Colorado, USA, has brought together space leaders from around the world to discuss, address and plan for the future of space since the inaugural event in 1984. In recent years, the Space Foundation team has welcomed more than 14,000 people from around the world, including speakers, attendees, exhibitors, volunteers, educators, and students. Space Symposium has become widely known as the premier U.S. space policy and program forum for information on and interaction among all sectors of space.

Surgical Robotics Technology Covers ThinGap As a Motor Leader

ThinGap has been covered in Surgical Robotics Technology as a leader regarding high-performance motor solutions for surgical robots.

Robert Mastromattei has showcased ThinGap’s frameless motors as being the ideal solution for high-precision surgical robotic applications in his latest publication on the website. After analyzing desired motor performance, focusing on characteristics such as zero-cogging, and large internal diameter, ThinGap’s LS series of motors are presented as the best solution for high-precision surgical applications.

Mastromattei details:

“A traditional frameless motor is shown below. The motor shown in Figure 2 is a slotless LS Series motor from ThinGap.  These motors have zero cogging and a large through hole. Km of these motors rivals some traditional slotted (or toothed) brushless permanent magnet motors.

Figure 2 Slotless Frameless Torque motor Example

Figure 3 below is a compact integrated Robot Joint for Surgical Robotics. It uses a frameless torque motor kit, high resolution medium accuracy absolute encoder on the input. It has a high ration zero backlash precision gear and a high accuracy absolute encoder on its output.”

Figure 3  Highly integrated Robot Joint

Source: Robert Mastromattei, Surgical Robotics Technology, July 2021. Link

ThinGap’s LS Series of slotless motor kits range in size from 25 to 267 mm outer diameter and continuous torque from 0.1 to 12.0 N-m. The LS motor offers torque performance equivalent to traditional frameless motor kits available on the market, unlike other slotless motor solutions which force a tradeoff between torque output and smoothness. With standard and modified standard configurations, the product line will cover voltages from 7-285 volts and current from 3-12 amps.