Servo Trigger Timing Compensation for Accurate Position Synchronization
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Solution Overview
Problem
Existing trigger signal generating devices for servo systems do not adequately account for delay times, leading to inaccuracies in synchronizing external devices with servo motors, particularly in high-speed component mounting applications where precise positioning is critical.
Innovation Solution
A trigger signal generating device that calculates and sets a timer setting time considering both servo side and external device side delay times, ensuring accurate output of the trigger signal to synchronize operations with the servo motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the encoder output signal is converted to linear position data using linear interpolation (Patent Document 1), then the reading errors of the encoder output signal are minimized and output accuracy is improved, but the required time period for arriving to the arrival position is not considered leading to insufficient trigger signal accuracy
Solution Approach 1:
The patent calculates the arrival time to the trigger position in advance based on current position and velocity information from the encoder. This preliminary calculation allows the trigger signal to be output at the precise moment the external device arrives at the trigger position, rather than using simple linear interpolation that ignores time dynamics. The system predicts future position based on current motion state to determine when the trigger event will occur.
2Loss of time
If the arrival position is predicted by calculating velocity and acceleration at sampled timings (Patent Document 2), then the time required for arriving to the arrival position is presumed, but the delay time at the external device side from trigger signal output to actual operation is not considered
Solution Approach 1:
The patent compensates for the external device's delay time by calculating it in advance and adjusting the trigger signal output timing accordingly. The system measures or estimates the delay time between when the external device receives the trigger signal and when it actually performs the operation, then uses this information to predict the true trigger position accounting for this delay. This preliminary compensation ensures the trigger signal is output at the correct moment despite the external device's inherent response delay.
3Productivity
If high-speed image capture is performed to confirm electronic part suction accuracy, then productivity is improved, but the trigger signal accuracy must be significantly improved to accurately capture the image at the predetermined position
Solution Approach 1:
The patent uses feedback from the encoder's position and velocity information to continuously update the predicted arrival time at the trigger position. This feedback mechanism allows the system to accurately determine when to output the trigger signal even during high-speed operations. By continuously monitoring the actual motion state and comparing it with the predicted trajectory, the system can precisely time the trigger signal output to coincide with the external device's arrival at the trigger position, enabling accurate high-speed image capture.
Data Source
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AI summary
A trigger signal generating device 6 is proposed which can output the trigger signal with high accuracy that gives instructions on operation to the external device 5 operated in synchronization with the servo motor 1. The trigger signal generating device 6 includes a timer setting time calculating portion 63 for calculating a timer setting time by subtracting a servo side delay time and an external device side delay time from a time required until the external device 5 arrives at an operation starting position calculated by a position information of the servo motor and a trigger signal outputting portion 64 for outputting a trigger signal based on the timer setting time, wherein the servo side delay time is defined to be a time period from a time when sampling by the position detecting device starts to a time when the calculation of the timer setting time for generating the trigger signal is completed and the external device side delay time is defined to be a time period from a time when the trigger signal is outputted to a time when the external device starts operation.