Rotary Table Clamp State Detection via Position Deviation
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Solution Overview
Problem
Existing rotary tables with direct drive systems require complex structures and increased costs due to the need for dedicated detectors to confirm clamping state, which prolongs the time required for clamp state confirmation.
Innovation Solution
A rotary table with a direct drive motor and position detector that uses oscillation-induced torque or speed variations to determine the clamping state through position deviation analysis, eliminating the need for additional sensors and simplifying the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a proximity switch or pressure sensor is incorporated into the rotary table to detect clamp state, then the clamp state can be confirmed, but the structure becomes complex and costs increase due to the need for mounting spaces, wiring, and piping
Solution Approach 1:
The rotary table uses its own built-in position detector to detect clamp state, eliminating the need for external sensors. The position detector already present in the direct drive system is utilized to detect the position of the clamp mechanism, allowing the system to self-diagnose the clamp state without additional detection devices
Solution Approach 2:
The position detector serves dual functions: it detects both the rotational position of the rotary table and the clamp state. By making the position detector multi-functional, the patent eliminates the need for separate clamp state detection devices, thereby simplifying the structure and reducing costs
2Reliability
If pressure sensor detection is used to confirm clamp state, then the clamp state can be detected, but the confirmation time is prolonged because clamping force is not applied at the instant pressure rises, requiring a fixed wait-time
Solution Approach 1:
The system performs preliminary detection of clamp state during the pressure rise phase itself, rather than waiting for pressure to stabilize. By continuously monitoring position detector signals during the clamping process, the system can determine clamp state completion at the moment it occurs, eliminating the need for fixed wait-time
Solution Approach 2:
The position detector provides real-time feedback on the clamp mechanism's position during the clamping process. This continuous feedback allows the control system to immediately detect when clamping is complete, enabling real-time clamp state confirmation without time delays
Data Source
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AI summary
When the clamp state of a rotating shaft of a motor that drives a rotary table is confirmed, a torque variation is applied from a servo controller to the motor without changing a position instructed by a numerical controller, and micro oscillations are induced in the rotating shaft. In a state in which the rotating shaft is nct clamped, the rotating shaft actually oscillates slightly in accordance with the applied torque variation. As a result, a fluctuation occurs in position deviation obtained based on position information fed back from a position detector. In a state in which the rotating shaft is clamped, on the other hand, the movement of the rotating shaft is restricted, so that either no or practically no fluctuation in position deviation occurs. A determination as to whether or not the rotating shaft is clamped is made on the basis of the size of the position deviation fluctuation (amplitude).