Autonomous Forklift Steering Control With Speed-Switched Servo Logic
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Solution Overview
Problem
Manual forklifts require specific training and are limited in operation, while fully autonomous forklifts are expensive and restrictive, and existing control systems for vehicles do not account for the unique needs of forklifts in factory environments.
Innovation Solution
A control system for forklifts that integrates human control elements with an automatic control module, a switching module, and a servo regulator using Proportional-Integral and All-Or-Nothing regulators based on speed thresholds, along with a navigation and detection module for assisted control and safety features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a PI controller is used for electro-hydraulic valve control, then control precision is improved, but response speed deteriorates due to delay
Solution Approach 1:
The system dynamically switches between PI controller and on/off controller based on real-time speed conditions. When speed is below threshold, PI controller provides precise control; when speed exceeds threshold, on/off controller provides fast response. This dynamic adaptation resolves the contradiction between precision and speed.
Solution Approach 2:
The controller type parameter is changed based on operating conditions (speed threshold). The system transitions from PI control parameters to on/off control parameters when speed conditions change, optimizing performance across different operating regimes.
2Speed
If an on/off controller is used for electro-hydraulic valve control, then response speed is improved, but control precision deteriorates
Solution Approach 1:
The system dynamically selects controller type based on speed threshold conditions. On/off controller is activated only when speed exceeds threshold, providing fast response when precision requirements are reduced due to higher speeds.
Solution Approach 2:
Control parameters are changed from on/off type to PI type when speed decreases below threshold, ensuring precise control when the system operates at lower speeds where precision is more critical.
3Extent of automation
If fully autonomous forklifts are deployed, then operational independence is improved, but cost increases significantly
Solution Approach 1:
The automation capability is segmented into discrete modes (manual, assisted, autonomous) rather than providing full autonomy by default. Users can select the appropriate level of automation based on their needs, reducing unnecessary costs while maintaining the option for higher automation when required.
Solution Approach 2:
The control system is designed to perform multiple functions across different operating modes using the same hardware infrastructure. The electro-hydraulic valve control system with switchable controllers serves both manual and autonomous operations, reducing overall system cost.
4Adaptability or versatility
If manual forklift operation is used, then operational flexibility is maintained, but operator training requirements increase
Solution Approach 1:
Operational modes are segmented to separate fully manual operation from assisted and autonomous modes. This allows facilities to implement the system at their desired level, maintaining flexibility while reducing training requirements proportionally to the level of automation implemented.
Solution Approach 2:
The control system acts as an intermediary between the operator and the forklift operations. In assisted mode, it provides support functions that reduce the skill gap, serving as a mediator that bridges the gap between manual operation and full automation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and safe operation of forklifts in various modes, including manual, assisted, and autonomous, enhancing productivity and safety in factory environments while maintaining a reasonable cost by leveraging existing infrastructure.
Implementation Method 1
an electro-hydraulic valve enabling the transformation of a control signal from the automatic control sub-module into a signal for the hydraulic steering
Implementation Method 2
a servo controller for the electro-hydraulic valve including a Proportional-Integral controller
Implementation Method 3
an on/off controller and means for activating either the PI or ON controller depending on a forklift speed threshold
Data Source
Figure 1~2
AI summary
The invention relates to a system for controlling a forklift truck, comprising: - human control means generating manual driving signals for vehicle actuators, these means including a hydraulic steering unit; - a control module (1) comprising an automatic control sub-module that generates autonomous driving signals intended for one or more vehicle actuators, according to control signals; - a switching module (2) designed to select one or more manual driving signals and/or one or more autonomous driving signals; - an electrohydraulic valve that allows a driving signal from the automatic control module to be converted into a signal for the hydraulic steering unit, the system being characterised in that it further comprises an electrohydraulic valve servo-control system comprising a proportional-integral controller, a two-position controller and means for activating either the proportional-integral controller or the two-position controller depending on a speed threshold of the forklift truck.