Configurable Feedforward Control for Motion Stage Vibration Isolation
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Solution Overview
Problem
Existing feedforward control systems for precision motion systems are topology-dependent, requiring cumbersome reprogramming and maintenance of libraries for different motion stage topologies, leading to inefficiencies and high costs.
Innovation Solution
A motion system with a configurable feedforward control that adapts to any motion stage topology on-site, using a hardware system with a memory to store motion equations defined by user-input strings and a processing unit to compute counteracting forces, supported by a user interface for editing and a digital bus for real-time data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedforward control is implemented with topology-specific motion equations, then compensation accuracy for reaction forces is improved, but device complexity and maintenance burden increase due to needing separate programs for each motion stage topology
Solution Approach 1:
The patent implements a universal feedforward control program that can handle multiple motion stage topologies (serial, parallel, hybrid) through a unified mathematical framework. The system uses a generalization of Newton's second law that works for any topology by defining virtual masses and inertial forces, eliminating the need for separate compiled programs for each topology type.
Solution Approach 2:
The system changes parameters dynamically by allowing the user to input topology-specific parameters (masses, inertias, coupling coefficients) into a universal equation framework. The virtual mass parameters can be adjusted based on the specific motion stage configuration, enabling the same program to adapt to different topologies without reprogramming.
2Adaptability or versatility
If a library of pre-compiled programs is maintained for different motion stage topologies, then support for various topologies is provided, but loss of time and productivity decrease due to cumbersome reprogramming and compilation requirements
Solution Approach 1:
The patent replaces the traditional mechanical approach of compiling and loading separate binary programs for each topology with a software-based parameter configuration approach. Users input topology parameters directly into the universal equations, and the system computes the appropriate control forces in real-time, eliminating compilation and library management overhead.
Solution Approach 2:
The system enables users to independently configure and adapt the feedforward control to their specific motion stage topology without requiring vendor support or complex reprogramming. The universal equations with adjustable parameters allow end-users to modify the control behavior for different topologies themselves, reducing dependency on external assistance.
3Measurement precision
If motion equations are computed inside the feedforward control for each topology, then accurate counteracting forces are generated, but ease of operation deteriorates due to the need for programming knowledge and on-site reconfiguration
Solution Approach 1:
The patent introduces an intermediary layer of virtual mass parameters that bridge the gap between complex motion equations and simple user input. Users only need to specify physical parameters (masses, inertias) of their motion stage, and the universal equations automatically compute the appropriate counteracting forces, hiding the mathematical complexity from the user.
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 flexible and efficient compensation of reaction forces across various motion stage topologies without the need for extensive reprogramming, reducing maintenance burdens and costs.
Implementation Method 1
The active vibration isolation system is controlled by the configurable feedforward control to compensate for expected reactions forces exerted by the motion stage on the base when operating
Data Source
AI summary
A motion system includes a motion hardware system and a motion control system configured to control the movement of the motion hardware system. The hardware system includes a motion stage, a platform supporting the motion stage, and a machine frame resting on a ground surface. The platform includes a base and an active vibration isolation system arranged between the base and the machine frame. The active vibration isolation system includes actuators to provide together at least three degrees-of-freedom actuation of the base. The motion control system includes a feedforward control having a vibration isolation system controller for controlling the at least three DOF actuation of the active vibration isolation system to compensate, by exerting a counteracting force on the base, for expected reactions forces exerted by the motion stage on the base when operating. The feedforward control includes a memory for storing a string of characters defining the motion equations based on the topology of the motion stage, and a processing unit for processing the string of characters to compute the counteracting force.