Reaction Sphere & Magnetorquers

Pick up suitable attitude actuators for your mission considering its max. torque and power consumption.
A spherical motor based variable-speed, single-gimbal control moment gyro combines the characteristics of reaction wheel and control moment gyro, is a novel tech that delivers nearly same performance but smaller in volume and weight comparing to traditional solutions.

RS100 - Reaction Sphere

Advanced satellites use control moment gyro (CMG) as their attitude actuator for having a better slew rate under the same power constraint. However, CMGs appear to be more expensive because of a more complicated control methodology and mechanical structure. Nevertheless, compared with reaction wheels with the same angular momentum storage capability, they have a larger output torque but are occupied with more volume and weight. 

Tensor Tech’s RS100 realizes a variable-speed, single-gimbal CMG driven by 2 degrees of freedom spherical motor technology. It successfully shrinks the volume and weight of a CMG by simplifying its mechanical structure. Although CMGs have comparingly complicated system dynamics, customers won’t have to worry about it. 

RS100 embeds a speed control mode and a torque control mode. Using the speed mode, customers can develop their ADCS algorithms with precise control to the inner rotor speed and the tilting angle of the CMG; Using the torque mode, customers can treat it as a torque output unit which RS100 propagates the control and steering laws internally and assuming the slew rate of the satellite is <1 deg/s.

RS200 - Reaction Sphere

The RS200 product is consists of two RS100 products. People call it a “scissor pair” if the tilting angles of two RS100 act reversely to each other. RS200 won’t completely do so because it is aiming for providing torque in 2 axes. 

We recommend installing RS200, aligning its gimballing axis (Z-axis) to the Z-axis of the satellite, which has the smallest moment of inertia. Magnetorquers should control this Z-axis. Like all other RS series products, the GNSS system and magnetorquers are optional. 

Single-gimbal CMG exerts gyroscopic torque in a direction that is orthogonal to its rotor shaft directional vector and tilting axis unit vector. Since the direction of this torque vector is varying through time, a scissor-pair CMG cluster can use each other to cancel the unwanted torques and utilize more gyroscopic torque instead of reaction wheel torque. (accelerating or decelerating the inner rotor) As a result, the torque-to-power ratio could be higher. Speed mode and torque mode are provided for customers to choose from building their torque output algorithm or using the one provided by Tensor Tech.

RS400 - Reaction Sphere

The RS400 product is consists of four RS100 products. People call it a “pyramid cluster”. It is the most common way of using single gimbal CMG because the redundancy is ensured and gyroscopic torque could be fully exerted in 3 axes. 

If customer’s deployer has four tuna-cans, we suggest to install these four RS100 in the bottom of the satellite like the picture showed below. If there has no such volume available, installing these four RS100 inside the CubeSat is feasible as well. Just remember to tell the RS400 the information of the position of these four RS100 during the setting process using Tensor Tech’s customer support software. 

Moreover, if customers plan to build your own ADCS using its speed mode, there already exist a mature steering law for these CMGs so customers won’t have to worry about how to control this cluster. If a torque mode is chosen, RS400 will output with the torque commanded by the on board computer using internally embedded control and steering algorithms.

Magnetorquer Rod & Air Coil

In low earth orbit environments, magnetorquers are used for satellite attitude control. For higher orbits, the earth’s magnetic field is too weak for utilizing these devices. 

They usually serve as direct actuators. Therefore, they can be used solely without the in-direct actuators like reaction wheels or control moment gyro. In contrast, having these indirect actuators and direct actuators altogether can increase the pointing control precision and the direct actuators and help the indirect actuators to do the de-saturation tasks.

Tensor Tech provides torquer rod and air coil type magnetorquers. The former has a nickel-based iron rod inside the device to increase its magnetic moment. Therefore, they could be made smaller in terms of size. The latter is purely a coil wounded with copper coils. Specs such as total resistance, max. magnetic moment could be tailor-made for customer’s needs.

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RS100 - Reaction Sphere

Advanced satellites use control moment gyro (CMG) as their attitude actuator for having a better slew rate under the same power constraint. However, CMGs appear to be more expensive because of a more complicated control methodology and mechanical structure. Nevertheless, compared with reaction wheels with the same angular momentum storage capability, they have a larger output torque but are occupied with more volume and weight. 

Tensor Tech’s RS100 realizes a variable-speed, single-gimbal CMG driven by 2 degrees of freedom spherical motor technology. It successfully shrinks the volume and weight of a CMG by simplifying its mechanical structure. Although CMGs have comparingly complicated system dynamics, customers won’t have to worry about it. 

RS100 embeds a speed control mode and a torque control mode. Using the speed mode, customers can develop their ADCS algorithms with precise control to the inner rotor speed and the tilting angle of the CMG; Using the torque mode, customers can treat it as a torque output unit which RS100 propagates the control and steering laws internally and assuming the slew rate of the satellite is <1 deg/s.

RS200 - Reaction Sphere

The RS200 product is consists of two RS100 products. People call it a “scissor pair” if the tilting angles of two RS100 act reversely to each other. RS200 won’t completely do so because it is aiming for providing torque in 2 axes. 

We recommend installing RS200, aligning its gimballing axis (Z-axis) to the Z-axis of the satellite, which has the smallest moment of inertia. Magnetorquers should control this Z-axis. Like all other RS series products, the GNSS system and magnetorquers are optional. 

Single-gimbal CMG exerts gyroscopic torque in a direction that is orthogonal to its rotor shaft directional vector and tilting axis unit vector. Since the direction of this torque vector is varying through time, a scissor-pair CMG cluster can use each other to cancel the unwanted torques and utilize more gyroscopic torque instead of reaction wheel torque. (accelerating or decelerating the inner rotor) As a result, the torque-to-power ratio could be higher. Speed mode and torque mode are provided for customers to choose from building their torque output algorithm or using the one provided by Tensor Tech.

RS400 - Reaction Sphere

The RS400 product is consists of four RS100 products. People call it a “pyramid cluster”. It is the most common way of using single gimbal CMG because the redundancy is ensured and gyroscopic torque could be fully exerted in 3 axes. 

If customer’s deployer has four tuna-cans, we suggest to install these four RS100 in the bottom of the satellite like the picture showed below. If there has no such volume available, installing these four RS100 inside the CubeSat is feasible as well. Just remember to tell the RS400 the information of the position of these four RS100 during the setting process using Tensor Tech’s customer support software. 

Moreover, if customers plan to build your own ADCS using its speed mode, there already exist a mature steering law for these CMGs so customers won’t have to worry about how to control this cluster. If a torque mode is chosen, RS400 will output with the torque commanded by the on board computer using internally embedded control and steering algorithms.

Magnetorquer Rod & Air Coil

In low earth orbit environments, magnetorquers are used for satellite attitude control. For higher orbits, the earth’s magnetic field is too weak for utilizing these devices. 

They usually serve as direct actuators. Therefore, they can be used solely without the in-direct actuators like reaction wheels or control moment gyro. In contrast, having these indirect actuators and direct actuators altogether can increase the pointing control precision and the direct actuators and help the indirect actuators to do the de-saturation tasks.

Tensor Tech provides torquer rod and air coil type magnetorquers. The former has a nickel-based iron rod inside the device to increase its magnetic moment. Therefore, they could be made smaller in terms of size. The latter is purely a coil wounded with copper coils. Specs such as total resistance, max. magnetic moment could be tailor-made for customer’s needs.

Subscribe to Access Our Newsletter and Technical Documents

Get the latest updates from Tensor Tech
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