Decoupled Position Regulators for Magnetic Motion Devices
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Solution Overview
Problem
Existing movement devices using magnetic forces for suspension and movement suffer from high energy losses and instability, particularly when using electromagnets, and struggle to maintain stable relative positions between subassemblies despite measurement errors and non-linear coupling of degrees of freedom.
Innovation Solution
A method employing permanent magnets to create stable magnetic forces for suspension and movement, utilizing separate position controllers for independent degrees of freedom, and employing non-linear coupling calculations to maintain stability and accuracy, with actuators like brushless DC motors for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electromagnets are used to generate magnetic forces for movement, then movement capability is achieved, but high energy losses occur
Solution Approach 1:
The patent replaces electromagnets (electrical system) with permanent magnets (magnetic system) to generate the magnetic forces needed for movement. This substitution eliminates the continuous energy consumption associated with electromagnets while maintaining the necessary magnetic field strength for suspending and moving the second subassembly.
Solution Approach 2:
The patent changes the source of magnetic field generation from an active electrical system (electromagnets requiring continuous power) to a passive magnetic system (permanent magnets). This parameter change fundamentally alters the energy consumption profile while preserving the magnetic force generation capability.
2Measurement precision
If separate position controllers are used for different degrees of freedom, then control precision is improved, but device complexity increases
Solution Approach 1:
The control system is segmented into separate position controllers for different degrees of freedom (x, y, z positions and rotational angles). Each controller independently manages one degree of freedom, which simplifies the control algorithm for each individual controller while achieving precise overall control through the combination of all controllers.
Solution Approach 2:
The calculation unit serves multiple functions: it receives actual position data from sensors, computes target positions for all actuators based on desired movement trajectories, and coordinates the work of multiple separate position controllers. This multi-functional approach reduces overall system complexity despite having multiple controllers.
3Loss of energy
If stable suspension is achieved using only permanent magnets, then energy efficiency is improved, but stability is compromised according to Earnshaw's theorem
Solution Approach 1:
The patent implements a closed-loop feedback control system where sensors continuously measure the actual relative position between the first and second subassemblies. This measured position data is fed to position controllers that calculate the required magnetic forces to achieve the desired position, which are then applied by adjusting the permanent magnet arrangements. This feedback mechanism actively compensates for disturbances and maintains stable suspension.
Solution Approach 2:
The patent transitions from a static magnetic field configuration to a dynamic one where the permanent magnet arrangements can be actively adjusted. By dynamically changing the position or orientation of permanent magnets based on feedback from position sensors, the system maintains stable suspension despite the inherent instability predicted by Earnshaw's theorem for static configurations.
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
The method achieves stable suspension and controlled movement with reduced waste heat, allowing for complex movement paths and high loads, while being computationally efficient and adaptable to measurement errors, ensuring dynamic stability and accuracy.
Implementation Method 1
it is possible to achieve the function known from WO 2015/017 933 A1 solely by using permanent magnets
Implementation Method 2
the forces for moving the active drive part are generated by eddy currents
Implementation Method 3
the magnetic forces are generated by means of electromagnets
Data Source
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AI summary
The invention relates to a method for operating a motion device comprising a first and a second assembly, wherein the first assembly comprises a first base and several first permanent magnet arrangements, wherein the first permanent magnet arrangements are connected to the first base via an associated actuator in such a way that they are movable as a whole in at least one degree of freedom relative to the first base by means of the associated actuator, wherein the second assembly comprises a second base and a second permanent magnet arrangement, wherein the second permanent magnet arrangement is fixedly arranged relative to the second base.According to the invention, at least two position controllers (12) are provided, each with a single scalar controlled variable and a single scalar manipulated variable (57), wherein the controlled variable is one of the six possible degrees of freedom with respect to a relative position between the first and the second assembly, wherein the manipulated variable (57) represents a force or torque which is assigned to this degree of freedom, wherein actuator setpoint positions of the actuators are calculated from the manipulated variables and/or determined using tables of values, and wherein the actuators are set accordingly.