Hydraulic Cylinder Control Device with Dynamic Linearization
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Solution Overview
Problem
Hydraulic cylinder control devices exhibit poor performance across varying operating points due to their dependence on specific operating conditions, and existing solutions like butterfly curves do not provide optimal control in all scenarios, making them inflexible and complex to implement.
Innovation Solution
A control device with a controller that determines a provisional manipulated variable based on setpoint and actual variables, followed by a linearization unit that dynamically adjusts factors to ensure the adjustment speed ratio is independent of piston position and working pressures, allowing for flexible and optimal control across different operating points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a controller optimized for a specific operating point is used, then control performance at that operating point is improved, but control performance at other operating points deteriorates
Solution Approach 1:
The patent applies dynamics by making the linearization factors dynamically adjustable based on the actual operating point (piston position and working pressures). Instead of using fixed linearization factors optimized for a single operating point, the system continuously adapts the factors to match current conditions, allowing optimal control performance across the entire operating range.
Solution Approach 2:
The patent changes parameters by dynamically adjusting the linearization factors based on measured piston position and working pressures. The controller modifies these factors in real-time to compensate for non-linearities at different operating points, transforming a static control system into one that adapts its parameters to maintain optimal performance across varying conditions.
2Measurement precision
If a butterfly curve control characteristic is used, then control behavior is improved at certain operating points, but it does not cover the entire space of possible operating points
Solution Approach 1:
The patent achieves universality by creating a control system that functions optimally across all operating points, not just specific ones. The dynamically adjustable linearization factors enable the same controller structure to adapt to any operating condition (any piston position and pressure combination), making the control system universally effective throughout the entire operating space.
Solution Approach 2:
The system transitions from a static butterfly curve to a dynamic linearization approach where factors are continuously adjusted based on actual operating conditions. This dynamic adaptation allows the control characteristic to change in real-time, covering the entire operating space rather than being limited to predefined curves for specific points.
3Measurement precision
If non-linear transformation is carried out independently for desired position and actual position with partial linearization, then control accuracy is improved, but implementation complexity increases
Solution Approach 1:
The patent merges the linearization operations by applying a single linearization step with dynamically adjusted factors to the controller output, rather than performing separate non-linear transformations on both desired and actual positions. This consolidation maintains control accuracy while significantly simplifying the implementation structure.
Solution Approach 2:
Instead of implementing complex independent non-linear transformations, the patent changes the approach by using parameter-adjusted linearization. The dynamic modification of linearization factors based on operating conditions provides the necessary accuracy without requiring multiple separate transformation stages, reducing implementation complexity.
Data Source
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AI summary
The device (11) has controllers (15,15') that determine preliminary manipulated variables (u,u') for valve control unit of hydraulic cylinder unit based on difference (delta s,delta F) between setpoint variables (s',F') and actual variables (s,F). A linearization unit (17) determines definitive manipulated variables (ua-ud) outputted to valve control unit, and determines linearization factors (fa'-fd') such that ratio of adjustment speed to difference between setpoint and actual variables is independent of position of piston and working pressures prevailing on sides of piston. An independent claim is included for a machine-readable media that contains software module storing machine code for controlling hydraulic cylinder unit.