NC Block Transition Blending for Discontinuous Trajectories
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing machine operating methods with numerical control facilities face challenges in maintaining high path speeds and short machining times when dealing with trajectories defined by parts programs with many block transitions and non-tangentially continuous contour profiles.
Innovation Solution
The method involves defining an acceleration duration different from the interpolation cycle period for at least one position-controlled axis, with a transition maximum acceleration and speed, ensuring the axis reaches zero speed at the end of the acceleration duration. A technology cycle with a second period, distinct from the interpolation cycle, is predefined, allowing for flexible setting of acceleration durations and transition maximum accelerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the path speed is maintained high through block transitions with discontinuous trajectories, then productivity increases, but manufacturing precision deteriorates due to trajectory inaccuracies and vibrations
Solution Approach 1:
The system performs preliminary actions by pre-calculating and storing optimal acceleration and deceleration profiles before block transitions occur. The numerical control facility computes transition parameters in advance, allowing the machine tool to execute smooth speed adjustments without real-time computational delays, thereby maintaining both high productivity and trajectory accuracy
Solution Approach 2:
The invention implements dynamic speed adjustment by continuously adapting the path speed during block transitions based on pre-calculated acceleration profiles. Instead of maintaining constant speed or using fixed deceleration- acceleration patterns, the system dynamically modifies velocity according to the specific transition requirements, resolving the contradiction between maintaining high speed and ensuring precision
2Productivity
If the interpolation cycle period is reduced to achieve higher path speeds, then productivity improves, but device complexity increases due to tighter control requirements and computational demands
Solution Approach 1:
The control system is segmented into distinct functional modules: a planning module that pre-calculates transition parameters, a storage module that buffers these parameters, and an execution module that implements them during interpolation cycles. This segmentation allows the system to handle short interpolation periods without overwhelming complexity, as each module performs a specific function independently
Solution Approach 2:
Transition parameters including acceleration profiles and speed adjustments are calculated and stored in advance before the interpolation cycles begin. This preliminary action shifts computational complexity from the real-time execution phase to the planning phase, allowing the interpolation cycle to run with simpler, pre-determined parameters while maintaining high path speeds
3Manufacturing precision
If acceleration duration is extended to reduce speed jumps at block transitions, then manufacturing precision improves, but loss of time increases reducing productivity
Solution Approach 1:
The system optimizes the acceleration duration by dynamically adjusting acceleration parameters based on the specific block transition requirements. Instead of using a fixed acceleration time that is either too long or too short, the numerical control facility calculates optimal acceleration profiles that achieve smooth transitions in the minimum necessary time, resolving the contradiction between precision and productivity
Solution Approach 2:
The acceleration process is made dynamic by adapting the acceleration rate and duration to each specific block transition. The system uses pre-calculated profiles that adjust acceleration characteristics based on the distance to the next block, the required path speed, and the machine tool's capabilities, achieving smooth transitions without excessive time loss
Data Source
AI summary
In a method for operating a machine having a trajectory determined by a parts program and including multiple block transitions with a non-tangential contour, a high trajectory speed and a short operating time are achieved. For a first position-controlled axis, an acceleration duration different from a first period duration can be specified, wherein a transition maximum speed for the first position-controlled axis is determined such that, when the first position-controlled axis moves with the transition maximum speed and the transition maximum acceleration is applied, the speed of the first position-controlled axis has a value of zero at the end of the acceleration duration. The traversing movement is determined such that the speed of the first position-controlled axis, at the transition from a first trajectory section to a second trajectory section, does not exceed the transition maximum speed.