Semi-Active Actuator Control via Virtual Model for Elevator Vibration
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Solution Overview
Problem
Conventional semi-active vibration reduction systems in industries like automotive and elevator systems face challenges due to the need for relative velocity measurements, which increase costs and reduce reliability, and are difficult to implement effectively.
Innovation Solution
A method and system that control semi-active actuators by approximating the optimal control policy based on a virtual system model, minimizing the number of sensors required, and using a virtual semi-active actuator to represent a set of actuators, allowing for uniform control and reduced complexity in measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semi-active vibration reduction systems use relative velocity measurements to control actuators, then vibration reduction performance is improved, but system cost and complexity increase
Solution Approach 1:
The patent creates a virtual model that copies the essential dynamics of the physical system, allowing control decisions to be made based on virtual state estimates rather than direct physical measurements. This virtual copy enables the system to achieve vibration reduction without requiring complex sensor arrays for direct velocity measurement.
Solution Approach 2:
The patent replaces the mechanical measurement system (velocity sensors) with a computational model-based approach. By substituting physical sensors with a virtual model that estimates system state, the system achieves the same control function with reduced hardware complexity and cost.
2Measurement precision
If relative velocity sensors are installed to measure vibration parameters, then control precision is improved, but system cost and reliability are worsened
Solution Approach 1:
The system uses readily available sensor data (position, acceleration) that is typically already present in the vehicle, and processes this information through the virtual model to derive the necessary control parameters. This self-service approach eliminates the need for additional specialized velocity sensors.
Solution Approach 2:
The virtual model acts as an intermediary that transforms easily measurable quantities (position, acceleration) into the derived quantities needed for control (velocity, force). This intermediary computation layer enables precise control without direct measurement of all parameters.
3Manufacturing precision
If multiple sensors are used to measure system parameters for actuator control, then control accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The virtual model serves multiple functions simultaneously: it estimates system state, predicts future behavior, and generates control commands. This multi-functional approach eliminates the need for separate measurement and control systems, reducing the total number of components required.
Solution Approach 2:
The patent merges the measurement, estimation, and control functions into a unified model-based control framework. By combining these previously separate functions into a single integrated system, the patent reduces the number of discrete sensors and control elements needed.
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
This approach effectively reduces vibrations while minimizing sensor usage and maintaining high performance, overcoming the limitations of conventional systems by simplifying the control policy and reducing costs.
Implementation Method 1
Vibration reduction in mechanical systems is important for a number of reasons including safety and energy efficiency of the systems
Implementation Method 2
The semi-active actuator allows for the adjustment of parameters, such as viscous damping coefficient or stiffness, and can be used to reduce the vibration
Data Source
AI summary
A set of semi-active actuators is arranged in an elevator system to compensate a vibration of an elevator car. The actuators are controlled in accordance with the control policy based on a measured signal including values of the parameter measured during the operation of the elevator system. The control policy is determined, based on a model of the elevator system, wherein the control policy includes a state function representing an operation of the elevator system and a function of displacement representing an operation of the set of semi-active actuators. The state function is approximated, using the model of the elevator system, as a first function of a parameter representing the vibration. The function of displacement is approximated, using the model of the elevator system, as a second function of the parameter.