Steering Actuator Speed Control for Aerial Work Platform Vehicles
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Solution Overview
Problem
In vehicles with aerial work platforms, high-speed travel leads to sensitive course changes due to constant steering angle displacement, compromising operability and ride comfort for the operator on the work platform.
Innovation Solution
A travel control device with a steering-angle control unit that adjusts the actuation speed of the steering actuator based on detected travel speed, reducing sensitivity at higher speeds and maintaining conventional control at lower speeds, and a travel speed controller that manages the travel speed based on operator input without additional speed measurement instruments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the steering angle is displaced at a constant speed irrespective of travel speed, then the steering system is simple to control, but the course change actuation becomes overly sensitive at high speeds, deteriorating operability and ride comfort
Solution Approach 1:
The steering actuator controller dynamically adjusts the actuation speed based on detected travel speed. When travel speed increases, the controller reduces the steering actuator's actuation speed to prevent overly sensitive course changes. This dynamic adaptation resolves the contradiction by making the steering system responsive to operating conditions while maintaining simplicity in control structure.
Solution Approach 2:
The system changes the steering actuator's actuation speed parameter according to the travel speed parameter. By establishing a relationship where higher travel speeds result in lower steering actuation speeds, the system maintains stable and comfortable course changes across different operating conditions without complicating the control mechanism.
2Measurement precision
If additional speed measurement instruments are added to detect travel speed for steering control adjustment, then the steering control precision is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The travel speed controller is designed to serve multiple functions: it controls the travel speed of the vehicle and simultaneously provides speed information to the steering actuator controller for steering adjustment. This multi-functionality eliminates the need for separate speed measurement instruments, reducing device complexity while maintaining the precision needed for adaptive steering control.
Solution Approach 2:
The existing travel speed controller serves itself by also providing speed data to the steering control system. The system uses its own operational data (travel speed) to automatically adjust steering actuation characteristics without requiring external measurement devices, thereby simplifying the overall device architecture.
Data Source
Figure 1~1(b)
Figure 2
Figure 3
AI summary
A vehicle with an aerial work platform (1) comprises a traveling body (10) having a steering wheel (12L, 12R) and capable of traveling, a revolving superstructure (20) provided on the traveling body, a boom (30) being vertically swingable, and a work platform (40) provided at a tip end of the boom. A travel control device for the vehicle comprises a steering operation device, a steering actuator (66) and a steering actuator controller (50) configured to control actuation of the steering actuator in response to operation of the steering operation device. The travel control device comprises a speed index-value detector (e.g. a tilt angle of the travelling operation lever 71) configured to detect a speed index value indicative of a travel speed of the traveling body. The steering actuator controller is configured to control the actuation of the steering actuator in response to the operation of the steering operation device and depending on the speed index value detected by the speed index-value detector.