Kinematics Control for Path Shifting in Multi-Axis Machines
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Solution Overview
Problem
Conventional control devices for machine tools cannot shift the movement path with respect to any coordinate system without increasing the calculation load of interpolation processing, particularly failing to handle rotations in five-axis milling machines and workpiece mounting errors.
Innovation Solution
A control device with a command analysis unit, interpolation unit, pulse generation unit, graph generation unit, shift addition node designation unit, shift information setting unit, and kinematics conversion unit that analyzes machining programs, generates movement commands, and converts program coordinates to motor coordinates, allowing for external movement adjustments without increasing interpolation processing load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If path shifting is performed through interpolation processing, then the movement path can be shifted, but the calculation load of interpolation processing increases
Solution Approach 1:
The patent extracts the path shifting function from the interpolation processing by introducing a separate coordinate system shift processing unit. This unit independently calculates coordinate transformations based on shift amounts and rotation angles, removing the computational burden from the interpolation unit while maintaining path shifting capability.
Solution Approach 2:
The patent introduces an intermediary coordinate system transformation unit that acts as a mediator between the program coordinate system and the machine coordinate system. This intermediary processes the coordinate transformations separately, allowing the interpolation unit to focus solely on its core function without the additional calculation load of path shifting.
2Adaptability or versatility
If coordinate system shift processing is added, then path shifting with respect to any coordinate system becomes possible, but the control device complexity increases
Solution Approach 1:
The patent implements a universal coordinate system transformation unit that can handle transformations for any coordinate system in the machine configuration. By designing this unit to work with arbitrary coordinate systems through graph-based representation, the system achieves versatility without proportionally increasing complexity.
Solution Approach 2:
The patent uses parameter-based coordinate system transformation where shift amounts and rotation angles are treated as adjustable parameters. This allows the same transformation unit to adapt to different coordinate systems by changing parameters rather than requiring separate processing logic for each system.
3Stability of the object's composition
If interpolation processing is used for path shifting, then continuous control can be maintained, but the processing time constraint becomes more difficult to meet
Solution Approach 1:
The patent extracts coordinate transformation calculations from the time-critical interpolation processing. By performing transformations in a separate unit before interpolation, the system maintains continuous control through interpolation while avoiding time constraints by eliminating transformation calculations from the critical path.
Data Source
AI summary
Provided is a control device capable of shifting the movement path of automatic operation with respect to a given coordinate system of a machine configuration, without increasing the calculation load of interpolating processing. This control device comprises: a command analysis unit; an interpolation unit; a pulse generation unit; a graph generation unit that generates a graph indicating a machine configuration of a machining tool and/or a robot; a shift additional node specification unit that specifies any node of the graph, in order to add, to the node of the graph, shift information including an external movement amount inputted from outside; a shift information setting unit that sets, on the basis of the shift information, the shift information with respect to a position offset and/or an attitude offset of the specified node; and a kinematics conversion unit that, on the basis of the position offset and/or the attitude offset set to the node, converts a program coordinate value included in the movement command to a motor coordinate value.