Electronic Safety Device for Steering Control Signal Blocking
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Solution Overview
Problem
The existing control systems for working machines, such as wheel loaders, face safety and cost efficiency challenges due to malfunctions in lever control systems, particularly when the steering lever is in a neutral position or locked, leading to unintended steering directions.
Innovation Solution
An electronic safety device is introduced between the control unit and the direction-changing device, comprising a control assembly with relays that only allows output signals to pass when corresponding to the operator-controlled element's position, ensuring safe operation by blocking control signals when the lever is in a neutral or incorrect position, and using independent switches to sense specific angular intervals for each steering direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If lever control with electronics is used to increase operator comfort and enable smooth control, then ease of operation is improved, but reliability deteriorates due to complex electronics with many sources of malfunction
Solution Approach 1:
A safety device is introduced as an intermediary component between the control unit and the steering cylinders. This safety device monitors the lever position and control signals, and can block control signals that do not correspond to the actual lever position, thereby preventing malfunctions while preserving the electronic lever control system's operational advantages
Solution Approach 2:
The safety device performs preliminary verification of control signals before they reach the steering cylinders. By checking whether control signals correspond to the actual lever position in advance, the system prevents unintended steering actions while maintaining the benefits of electronic control
2Reliability
If high quality demands are placed on machine computer and electronics to ensure safety, then reliability is improved, but device complexity increases resulting in high costs
Solution Approach 1:
The control system is segmented into distinct functional components: the control unit, the safety device, and the steering cylinders. The safety device is a separate, dedicated component that handles safety verification independently, allowing the main control electronics to remain relatively simple while still achieving high safety standards
Data Source
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AI summary
The invention relates to a control system (300) for a working machine (101), comprising a device (301) for changing direction of the working machine, an operator controlled lever (307), and an electronic control unit (351) adapted to receive an input signal indicative of desired direction from the position of the operator controlled element and to generate an output signal for producing a change of direction of the working machine, corresponding to the position of the operator controlled element, via said device (301). The control system (300) comprises an electronic safety device (353) adapted to be controlled by the position of the operator controlled element (307) and adapted to allow control of the device (301) via said output signal and to block control of the device (301) via said output signal, respectively, depending on the position of the operator controlled element.