Robot Joint Encoder Reference Recovery After Power Loss
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Solution Overview
Problem
In robots used for manufacturing, the loss of encoder detection values due to battery exhaustion or reliability issues leads to discrepancies in joint angle reference positions, necessitating re-teaching and increasing stop times, which decreases operation rates.
Innovation Solution
A robot system with redundant encoders for each joint, where the reference position of one encoder is restored using the other, allowing for continuous operation without re-teaching, even when battery reliability is compromised.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single encoder with battery backup is used to detect joint angle, then the reference position can be maintained during operation, but the reliability decreases when battery consumption or power supply failure occurs
Solution Approach 1:
The patent applies local quality by making the two encoders have different functional characteristics: the first encoder (with battery) maintains reference position information during power interruptions, while the second encoder (without battery) provides continuous real-time detection. Each encoder is optimized for its specific role, and together they compensate for each other's weaknesses.
Solution Approach 2:
The patent changes the operational parameters of the encoders by switching between them based on power supply status. When power is available, the first encoder's reference position is used; when power is interrupted, the system switches to the second encoder's continuous detection values, thereby adapting to changing conditions and maintaining reliability.
2Measurement precision
If encoder reference position is restored after power interruption, then detection accuracy is improved, but robot stop time increases and operation rate decreases
Solution Approach 1:
The patent applies preliminary action by pre-establishing reference position information in the first encoder before power interruptions occur. This reference position is stored in memory and can be immediately retrieved after power restoration, eliminating the need for time-consuming re-teaching procedures and thereby maintaining high operation rates.
Solution Approach 2:
The patent uses copying by transferring reference position information from the first encoder to the control system after power restoration. Instead of re-teaching the entire reference position, the system copies the stored reference values and applies them immediately, significantly reducing restoration time and maintaining productivity.
3Reliability
If redundant encoders are installed for each joint, then reliability against power failure is improved, but device complexity increases
Solution Approach 1:
The patent applies merging by combining the functions of two encoders into a unified detection system. The first encoder provides reference position information with power backup, while the second encoder provides continuous real-time detection. Both encoders work together under a single control algorithm that automatically selects or combines their outputs, achieving high reliability without proportionally increasing system complexity.
Data Source
AI summary
A robot having a joint, the robot comprising a first position sensor and a second position sensor configured to acquire information about a position of the joint, wherein a first reference position of the first position sensor is acquired based on a second reference position of the second position sensor.