Gantry Platform Kinematics for Rail Parallelism and Squareness Errors
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Solution Overview
Problem
Existing gantry platforms with dual-drive structures face challenges in achieving high positioning precision due to parallelism errors between guide rails and insufficient perpendicularity precision between the crossbeam and guide rails, leading to structural deformation, vibration, and inefficient energy consumption. Existing methods fail to address the issues of complex structure and low precision in drive control.
Innovation Solution
A gantry platform kinematics modeling method considering parallelism and perpendicularity errors, involving a forward and inverse kinematics solution, and a gantry platform device comprising a crossbeam, guide rails, and motors, with a transverse motor to drive the platform, and a controller for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pure position-synchronized movement is used for motors Y1 and Y2, then the control method is simple, but parallelism error between guide rails and insufficient perpendicularity precision cause severe forced deformation and vibration
Solution Approach 1:
The patent transforms the control approach from pure position-synchronized movement to a coordinated control method that dynamically adjusts motor positions based on calculated compensation values. The control parameters are changed to account for parallelism error (α) and perpendicularity error (β), allowing the system to adapt to actual mechanical deviations while maintaining simple hardware structure.
Solution Approach 2:
The patent implements a feedback mechanism where the actual positions of motors Y1 and Y2 are continuously monitored, and compensation values are calculated based on the measured deviations from the ideal kinematic model. This feedback loop enables the system to correct for parallelism and perpendicularity errors in real-time, improving positioning precision without adding complex mechanical structures.
2Manufacturing precision
If flexible supporting device is used to connect motors to crossbeam, then positioning precision is improved, but device structure and control method become complex
Solution Approach 1:
The patent replaces the mechanical flexible supporting device with a computational solution. Instead of using physical flexible elements to accommodate errors, the system uses kinematic modeling and coordinate transformation to calculate and compensate for deviations mathematically. This substitution maintains positioning precision while significantly simplifying the device structure.
Solution Approach 2:
The patent changes the control parameters to include compensation values derived from kinematic models that account for parallelism and perpendicularity errors. By modifying the control equations to incorporate these error parameters, the system achieves high positioning precision without requiring complex flexible mechanical structures.
3Manufacturing precision
If calibration method calculating offset angle and amount is used, then positioning precision is improved, but parallelism error and perpendicularity error are not accounted for
Solution Approach 1:
The patent extends the calibration method by adding parallelism error (α) and perpendicularity error (β) as additional parameters to the kinematic model. This enhancement allows the system to account for all three major sources of error (offset angle, parallelism, and perpendicularity), significantly improving the accuracy of error measurement and compensation.
Solution Approach 2:
The patent expands the calibration approach from considering only offset angle in one dimension to incorporating parallelism and perpendicularity errors in multiple dimensions. By adding these additional error dimensions to the kinematic model, the system achieves more comprehensive and precise error measurement and compensation.
4Speed
If redundant drive structure is used for gantry platform, then long travel and high speed are achieved, but coupling between motors causes difficulty in coordinated movement
Solution Approach 1:
The patent implements a feedback-based coordinated control system that continuously monitors the positions and velocities of both motors in the redundant drive structure. By using real-time position feedback and calculating compensation values based on the kinematic model, the system achieves highly coordinated movement between motors Y1 and Y2, eliminating coupling issues while maintaining the long travel and high speed capabilities.
Solution Approach 2:
The patent modifies the control parameters to include compensation values that account for the coupling effects in the redundant drive structure. By dynamically adjusting motor commands based on actual position deviations and the calculated kinematic model, the system achieves smooth coordinated movement while preserving the performance advantages of redundant drive.
Data Source
AI summary
The invention relates to the technical field of intelligent control, and particularly to a gantry platform kinematics modeling method considering parallelism and perpendicularity errors, which is applied to a gantry platform device. The gantry platform device comprises a crossbeam, a first guide rail and a second guide rail, one end of the crossbeam is in sliding fit with the first guide rail, and the other end of the crossbeam is in sliding fit with the second guide rail; the first guide rail is provided with a first longitudinal motor, and the second guide rail is provided with a second longitudinal motor; and the crossbeam is provided with a transverse motor configured to drive the gantry platform to move along the crossbeam. The method comprises: establishing a two-dimensional coordinate system; constructing a forward kinematics solution model; and constructing an inverse kinematics solution model.