Industrial Vehicle Axle Control with Threshold Differentiation
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Solution Overview
Problem
The combination of swing lock and vehicle speed limiting functions in industrial vehicles can cause control interference when both functions are set to the same threshold value, leading to an uncomfortable time lag for operators during turning, affecting the stability and smoothness of the vehicle's operation.
Innovation Solution
An industrial vehicle equipped with a lateral acceleration sensor, an actuator to restrict axle pivoting, and a controller that sets different threshold values for pivoting and speed limiting based on measured lateral acceleration, ensuring the vehicle speed is limited before axle restriction, thereby preventing control interference and enhancing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the same threshold value is used for both swing lock control and vehicle speed limiting control, then lateral stability of the vehicle is ensured, but control interference occurs causing time lag and uncomfortable operation
Solution Approach 1:
The patent applies different threshold values to different control functions: a first threshold value for swing lock control and a second threshold value for vehicle speed limiting control. This local differentiation allows each control function to operate optimally without interference, eliminating the time lag and uncomfortable operation while maintaining lateral stability through coordinated control.
2Stability of the object's composition
If the swing lock function is activated to restrict axle pivoting, then vehicle stability is improved, but time lag occurs between command signal and actual restriction
Solution Approach 1:
The patent activates the vehicle speed limiting control before the swing lock control by using a lower second threshold value that triggers speed limiting at smaller lateral acceleration. This preliminary action prepares the vehicle for upcoming swing lock activation, reducing the time lag and making the transition smoother and less noticeable to the operator.
3Stability of the object's composition
If vehicle speed is limited during turning, then lateral stability is maintained, but vehicle productivity decreases
Solution Approach 1:
The patent dynamically adjusts the vehicle speed limit based on the actual lateral acceleration experienced during turning. The speed limiting control activates only when lateral acceleration exceeds the second threshold value, allowing the vehicle to maintain higher speeds during gentle turns while ensuring stability during sharp turns. This dynamic adjustment optimizes both stability and productivity.
Data Source
AI summary
The industrial vehicle includes a body, an axle, a lateral acceleration sensor determining lateral acceleration, an actuator temporally restricting pivoting of the axle, a vehicle speed limiter limiting vehicle traveling speed, and a controller driving the actuator based on the lateral acceleration determined by the lateral acceleration sensor to temporally restrict pivoting of the axle while the industrial vehicle is being turned and to limit traveling speed of the industrial vehicle based on lateral acceleration determined by the lateral acceleration sensor when the industrial vehicle is turned. A first lateral acceleration threshold value which is used in judging whether traveling speed of the industrial vehicle should be limited is set smaller than a second lateral acceleration threshold value which is used in judging whether pivoting of the axle should be temporally restricted. An upper limit deceleration rate is set for limiting the traveling speed of the industrial vehicle.