Dual Drive Force Coil System for Wide Dynamic Range Control
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Solution Overview
Problem
Conventional force coil drive systems lack the ability to efficiently produce output forces over a wide range with high resolution and low noise, particularly in transitioning between high-force efficient operations and low-force noise-free operations, which can disturb payloads and induce vibrations.
Innovation Solution
A system comprising a pulse width modulation (PWM) drive and a linear drive, where the PWM drive efficiently produces high forces and the linear drive generates low-level, high-resolution, noise-free forces, with three operational modes to optimize efficiency and minimize noise/ripple across different force ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single force coil is driven by a single drive system, then the device complexity is reduced, but the ability to efficiently produce forces over a wide range with high resolution and low noise deteriorates
Solution Approach 1:
The patent divides the force coil drive system into two separate drive channels: a PWM drive channel for high-force efficient operation and a linear drive channel for low-force noise-free operation. This segmentation allows each drive to be optimized for its specific operating range, resolving the contradiction between device simplicity and adaptability across wide force ranges.
Solution Approach 2:
The system dynamically switches between PWM and linear drive modes based on the required force level. The control system automatically selects the appropriate drive type for the current operating conditions, enabling the system to adapt its characteristics (efficiency vs. noise performance) to match the demanded force range.
2Productivity
If PWM drive is used to efficiently produce high forces, then the productivity is improved, but the noise and ripple increase
Solution Approach 1:
The patent separates the force production task into two segments: PWM drive handles high-force production where efficiency is paramount and noise is acceptable, while linear drive handles low-force production where noise must be minimized. This segmentation resolves the contradiction by assigning each drive type to its optimal operating regime.
Solution Approach 2:
The control system acts as an intermediary that directs the appropriate drive type based on force requirements. It mediates between the conflicting demands of efficiency and noise by selecting PWM mode for high-force tasks and linear mode for low-force tasks, ensuring optimal performance for each operating condition.
3Object-affected harmful factors
If linear drive is used to produce low noise forces, then the harmful factors are reduced, but the efficiency and power handling capability deteriorate
Solution Approach 1:
The patent segments the operating range into low-force and high-force regions, assigning linear drive to the low-force region where noise performance is critical and PWM drive to the high-force region where efficiency is critical. This segmentation allows each drive type to operate in its optimal efficiency zone.
Solution Approach 2:
The system changes the operating parameters (drive type selection) based on the required force level. By transitioning between linear and PWM drive modes, the system optimizes the efficiency parameter for each operating point, using linear drive for low-power applications and PWM drive for high-power applications.
4Power
If the force coil is driven at high current levels for re-orientation, then the power is improved, but the resolution and noise performance deteriorate
Solution Approach 1:
The patent segments the force output range into two zones: a high-force zone (±1 lbf to ±100 lbf) served by PWM drive where power capability is prioritized, and a low-force zone (±0.0005 lbf to ±1 lbf) served by linear drive where resolution and noise performance are prioritized. This segmentation resolves the contradiction between power and precision.
Solution Approach 2:
The system dynamically adjusts the drive mode based on the required force magnitude. When high power is needed for re-orientation, PWM drive is engaged; when high precision is needed for fine adjustments, linear drive is engaged. This dynamic adaptation ensures optimal resolution at each power level.
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 efficient and precise force control over a wide range, from +100 lbf to -100 lbf with a resolution of 0.0005 lbf, while minimizing noise and ripple, thereby maintaining a vibration-free environment for sensitive payloads.
Implementation Method 1
The PWM drive is configured to drive the first coil to apply a first force
Implementation Method 2
The linear drive is configured to drive the second coil to apply a second force
Data Source
AI summary
Methods and systems are provided for driving one or more force coils. A system for driving force coils is provided including a PWM drive coupled to a first coil and a linear drive coupled to a second coil. The PWM drive efficiently drives the first coil to apply a first force. The linear drive drives the second coil to apply a second force that is substantially noise-free. The first force is greater than the second force.