Forklift Steer-by-Wire Weight Detection via Delay Time
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Solution Overview
Problem
Conventional forklifts with steer-by-wire systems require additional parts and increased device costs to recognize the weight of objects being conveyed, which complicates the steering mechanism and increases operational risks.
Innovation Solution
Incorporating a storage unit for load/time information, a delay time detection unit, a weight identifying unit, and optional frictional coefficient measurement and correction units within the steer-by-wire system, allowing the forklift to recognize the weight of the object based on the delay time for the steered wheels to reach corresponding angles, without the need for a load sensor mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a load sensor mechanism is added to measure the weight of the object, then the weight recognition accuracy is improved, but the device complexity and cost increase
Solution Approach 1:
The steer-by-wire system performs self-diagnosis by utilizing its own existing sensors (steering wheel angle sensor and steered wheel angle sensor) to detect delay time, which correlates with load weight. The system serves its own measurement need without requiring external load sensor mechanisms, thereby avoiding increased device complexity while achieving weight recognition.
Solution Approach 2:
The patent replaces the mechanical load sensor mechanism with an electrical/electronic measurement approach. Instead of using mechanical sensors to directly measure weight, the system uses electrical signals from angle sensors to detect delay time, which is then converted to weight information through control unit processing. This substitution eliminates the need for mechanical load sensing components.
2Measurement precision
If a load sensor mechanism is added to measure the weight of the object, then the weight recognition accuracy is improved, but the device cost increases
Solution Approach 1:
The steer-by-wire system performs self-diagnosis by utilizing its own existing sensors (steering wheel angle sensor and steered wheel angle sensor) to detect delay time, which correlates with load weight. The system serves its own measurement need without requiring external load sensor mechanisms, thereby avoiding increased device cost while achieving weight recognition.
Solution Approach 2:
Instead of directly measuring weight with specialized sensors, the system creates an indirect measurement by copying the relationship between delay time and load weight. The control unit measures delay time (an easily obtainable parameter) and uses stored correspondence data to determine weight, effectively copying the weight information from a measurable proxy rather than measuring weight directly.
3Speed
If the steering response is made faster, then the operational speed is improved, but the stability decreases when carrying heavy loads
Solution Approach 1:
The patent implements dynamic steering control by adjusting the steering response characteristics based on the detected load weight. When heavy loads are detected, the system automatically modifies the steering response to be more gradual and stable. When light loads are detected, the system allows for faster steering response. This dynamic adjustment optimizes both speed and stability according to actual operating conditions.
Solution Approach 2:
The system uses feedback from the delay time detection to continuously adjust steering control parameters. The control unit receives feedback about the current load condition through delay time measurement and automatically adjusts the steering response characteristics accordingly, creating a closed-loop control system that maintains optimal performance across varying load conditions.
Data Source
AI summary
Provided is a forklift capable of recognizing an approximate weight of an object to be conveyed supported by a fork without adding special parts. A control unit includes a storage unit which stores load/time information indicating a relationship between a delay time required for an angle of rear wheels to reach an angle corresponding to an angle of the steering wheel and a weight of the object to be conveyed supported by the fork at that time, a delay time detection unit which detects the delay time required for a steering angle of the rear wheels to reach the angle corresponding to the angle of the steering wheel, and a weight identifying unit which identifies the weight of the object to be conveyed supported by the fork on the basis of the delay time detected by the delay time detection unit and the load/time information stored in the storage unit.