Linear Actuator Power Control for Low-Power Spacecraft Docking
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Solution Overview
Problem
Conventional docking devices cannot be mounted on spacecraft with small power supply capacity due to insufficient power supply to the motor of the linear actuators, leading to increased manufacturing costs.
Innovation Solution
A power controller for the linear actuator in a docking device with a motor driver that includes a speed controlling unit, a current controlling unit, and a current command limiter, which limits the current command to ensure power consumption per actuator is one-sixth or less of the power supply capacity, allowing efficient power management without requiring modifications to the spacecraft's power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the docking device is mounted on a spacecraft with small power supply capacity, then the power supply capacity is insufficient for the motor of the linear actuators, but modifying the spacecraft to increase power supply capacity increases manufacturing costs
Solution Approach 1:
The patent changes the control parameters of the motor driver to optimize power consumption. By adjusting the current command limiter and speed control parameters, the system achieves adequate performance with reduced power consumption, allowing mounting on spacecraft with small power supply capacity without modification.
2Use of energy by moving object
If the current command is limited to reduce power consumption per actuator to one sixth or less of the power supply capacity, then the docking device can be mounted on spacecraft with small power supply capacity, but the extension and contraction speed of the linear actuators may be reduced
Solution Approach 1:
The patent applies partial action by limiting the current command to achieve one sixth or less of the power supply capacity per actuator. This partial current limitation is sufficient to enable mounting on small-capacity spacecraft while maintaining acceptable docking performance through coordinated control of multiple actuators.
Solution Approach 2:
The motor driver is designed to perform multiple functions: speed control, current limiting, and power management. By integrating these functions, the system can operate effectively within constrained power supplies while still achieving the required docking operations.
3Adaptability or versatility
If the power consumption per linear actuator is limited to one sixth or less of the power supply capacity for the motor power, then the docking device can be mounted without modification, but the total power available per actuator is reduced
Solution Approach 1:
The patent segments the power distribution by allocating one sixth or less of the total power supply capacity to each individual actuator. This segmentation allows the system to adapt to spacecraft with small power supplies by distributing limited power across multiple actuators rather than requiring high power per actuator.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the mounting of the docking device on spacecraft with small power source capacity without increasing the power supply capacity, reducing manufacturing costs while maintaining effective misalignment correction and inertial force attenuation.
Implementation Method 1
a current command limiter between the speed controlling unit and the current controlling unit, wherein the current command limiter limits the current command so that power consumption per one linear actuator is one sixth or less of the power supply capacity for the motor power
Data Source
AI summary
A power controller of a linear actuator 10 in a docking device 1 including a six-axis parallel link mechanism 5, wherein a motor driver 11 configured to control rotation speed of a motor M of the linear actuator 10 on the basis of a load produced on the link 4 includes a speed controlling unit 31 that outputs a current command, a current controlling unit 32 that converts the current command to a voltage command, and a current command limiter 33 that limits the current command of the speed controlling unit 31 so that power consumption per one linear actuator 10 is one sixth or less of the power supply capacity for the motor power, thus allowing for mounting the docking device 1 even for a spacecraft with a small power supply capacity, without requiring modification of the power supply capacity.