Electric Wheelchair Failure Detection via Speed Difference
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Solution Overview
Problem
Existing movable body failure detection systems, such as those in electric wheelchairs, require multiple sensors and dual sub-systems, leading to increased complexity and cost, making it challenging to detect failures in the traveling function effectively.
Innovation Solution
A movable body with a disconnecting device, actual driving amount detecting device, control device, failure detecting portion, and disconnecting control portion that calculates speed differences between presumed and actual speeds to detect failures without multiple sensors or dual sub-systems, simplifying the structure and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual system with multiple sensors and sub-systems is used to detect failures, then the reliability of failure detection is improved, but the device complexity and cost increase
Solution Approach 1:
The system uses its own existing sensors and control units to perform self-diagnosis. The control unit compares the operation amount from the operating device with the actual driving amount from sensors to detect failures, eliminating the need for separate dual systems.
Solution Approach 2:
Existing sensors and control units are made multi-functional. The same sensors that monitor normal operation are also used for failure detection by comparing expected vs actual values, reducing the need for additional dedicated failure detection components.
2Reliability
If a dual system with multiple sensors and sub-systems is used to detect failures, then the reliability of failure detection is improved, but the cost increases
Solution Approach 1:
The system uses its own existing sensors and control units to perform self-diagnosis. The control unit compares the operation amount from the operating device with the actual driving amount from sensors to detect failures, eliminating the need for separate dual systems.
Solution Approach 2:
Existing sensors and control units are made multi-functional. The same sensors that monitor normal operation are also used for failure detection by comparing expected vs actual values, reducing the need for additional dedicated failure detection components.
3Difficulty of detecting and measuring
If multiple sensors and dual sub-systems are combined to achieve failure detection, then the detection capability is improved, but the device complexity increases
Solution Approach 1:
The system uses its own existing sensors and control units to perform self-diagnosis. The control unit compares the operation amount from the operating device with the actual driving amount from sensors to detect failures, eliminating the need for separate dual systems.
Solution Approach 2:
The system continuously compares the expected driving amount (from operation signal) with the actual driving amount (from sensors) and uses this feedback to detect failures. This feedback mechanism enables failure detection using existing components without adding complex dual systems.
Data Source
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Figure 3~4B
AI summary
The movable body, having a failure detecting structure which detects a failure in a travelling function of the movable body can be provided with low in cost and the failure detecting portion of the electric wheel chair includes a first speed presuming portion which presumes the straight travelling speed of the electric wheel chair based on an operating signal of the operating device, a second speed presuming portion which presumes the straight traveling speed of the electric wheel chair based on the actual driving amount detected by the actual driving amount detecting device, a speed difference calculating portion which calculates the first straight traveling speed difference which is a speed difference between the straight travelling speed presumed by the first speed presuming portion and the straight traveling speed presumed by the second speed presuming portion and a failure judging portion which judges that a failure exists in the traveling function when the first straight travelling speed difference is equal to or more than the first straight travelling difference judging value.