Encoder Backup Current Abnormality Detection
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Solution Overview
Problem
Existing encoders with backup batteries lack a method to determine abnormalities in backup current consumption, leading to potential early power depletion without detection.
Innovation Solution
An encoder with a current obtaining portion to measure backup current and a current abnormality determining portion that compares the backup current to a given value based on the rotational speed of the object of detection, determining abnormalities when the current exceeds this value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the backup battery supplies electric power to the main circuit continuously, then the rotation angle can be detected even when the main power supply is off, but the backup current may be abnormal causing early power depletion
Solution Approach 1:
The patent applies preliminary action by checking the backup current before it causes abnormal power depletion. The current checking portion continuously monitors the backup current during backup operation, and when an abnormality is detected (current exceeds threshold for a predetermined time), the system proactively determines battery failure and switches to a power-saving mode. This prevents the battery from depleting due to undetected abnormalities, thereby extending effective battery life while maintaining detection reliability.
2Reliability
If the backup current is checked continuously, then abnormalities can be detected early, but the power consumption of the checking circuit increases
Solution Approach 1:
The patent implements periodic action by checking the backup current at regular intervals during backup operation rather than continuously. The current checking portion monitors the backup current periodically, and when an abnormal current is detected for a predetermined time period, the system determines battery failure. This periodic checking approach maintains adequate abnormality detection capability while significantly reducing the power consumption of the checking circuit compared to continuous monitoring.
3Productivity
If the main circuit operates with abnormal backup current, then the rotation angle detection continues, but the backup battery power is consumed early
Solution Approach 1:
The patent applies feedback by continuously monitoring the backup current during operation and using this information to control the operation mode. When the current checking portion detects that the backup current exceeds a predetermined threshold for a predetermined time, the operation mode determining portion receives this feedback and switches the system to a power-saving operation mode. This feedback mechanism ensures that detection continuity is maintained when the battery is healthy, but automatically reduces power consumption when abnormal current is detected, thereby extending backup battery life.
Data Source
AI summary
An encoder for detecting a rotation angle of an object of detection includes: a main circuit including a rotational speed obtaining portion configured to obtain a rotational speed of the object of detection; a backup battery for supplying power to the main circuit while the main circuit is disconnected from a main power-supply circuit; a current obtaining portion configured to obtain a consumption current of the backup battery as a backup current while the electric power is being supplied from the backup battery to the main circuit; and a current abnormality determining portion configured to determine that the backup current is abnormal if the backup current is larger than a given current value when the rotational speed of the object of detection obtained by the rotational speed obtaining portion is a given rotational speed.