Numerical Controller Braking Path for Collision-Free Machine Stops
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Solution Overview
Problem
Existing collision avoidance systems in production machines fail to effectively account for real-time events, leading to potential collisions and reduced productivity due to the requirement of maintaining minimum distances or uncontrolled braking.
Innovation Solution
A method that determines current and expected position setpoints for position-controlled axes, checks for collision risks, and if a risk is detected, brings the axes to a standstill along a previously checked collision-free path stored in a braking path memory, allowing for recalculating new paths as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If real-time events are not considered in collision prediction, then processing complexity is reduced, but collision risk increases due to unexpected spontaneous movements
Solution Approach 1:
The system performs preliminary collision checks for expected position setpoints before actual movement occurs. By predicting future positions and checking for collisions in advance, the system accounts for real-time events without requiring complex real-time processing during execution, thus reducing processing complexity while maintaining reliability
2Reliability
If minimum distance is maintained between machine elements, then collision avoidance is ensured, but productivity is reduced due to restricted movement capabilities
Solution Approach 1:
The system dynamically changes the collision safety parameter from a fixed minimum distance constraint to a variable safety margin based on predicted trajectories. By calculating collision risks for specific expected position setpoints, the system allows elements to approach closer than traditional minimum distances would permit, thereby improving productivity while maintaining collision avoidance through intelligent parameter adaptation
3Reliability
If uncontrolled braking is used to stop axes, then collision can be avoided, but productivity is reduced due to frequent stopping and inability to maintain optimal speeds
Solution Approach 1:
The system performs preliminary collision checks for expected position setpoints before movement execution. By identifying and avoiding collision-prone trajectories in advance, the system eliminates the need for emergency uncontrolled braking, allowing axes to maintain optimal speeds throughout the workflow and significantly improving productivity while preserving collision avoidance
Data Source
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AI summary
A numerical controller (4) uses specifications (VI, V2) for position-controlled axes (1) of a production machine controlled by the numerical controller (4), for example a robot, a manipulator, a machine tool, to determine a current group of position setpoint values (xi*) and also determines groups of position setpoint values (xi*) expected for a forecast horizon (H). The numerical controller checks whether, when controlling the position-controlled axes (1) using the current group of position setpoint values (xi*), there is the risk of a collision between at least one element (2, 3) moved by controlling the position-controlled axes (1) and at least one other element (2, 3, 9, 10). The numerical controller carries out the same check for the expected groups of position setpoint values (xi*). If the numerical controller does not detect any risk of a collision, it stores the expected groups of position setpoint values (xi*) in a braking path memory (11) and controls the position-controlled axes (1) using the current group of position setpoint values (xi*). The numerical controller (4) repeats this procedure as long as it does not detect any risk of a collision. If, in contrast, the numerical controller detects the risk of a collision, it changes the position-controlled axes (1) along a path (12) to a standstill defined by groups of position setpoint values (xi*) stored in the braking path memory (11). If the numerical controller therefore detects the risk of a collision, braking is effected along a path which has already been previously checked for the risk of a collision and for which no risk of a collision has been detected. The change to the standstill can therefore be carried out along a path on which a collision does not occur.