Wheel Loader Joystick Zero-Point Shift for Smooth Steering
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Solution Overview
Problem
Existing work machine control systems, such as wheel loaders, experience non-uniform movements and unwanted effects on control behavior due to the lack of elasticity in spring mechanisms, leading to 'stick-slip' effects and jerky movements, which can result in dangerous situations.
Innovation Solution
The introduction of an adjusting device that shifts the middle position of the spring assembly, allowing for a zero-point shift within the sensor measuring range, combined with a self-locking gear and optional active or passive actuation, to maintain steerability even when the spring assembly is incorrectly tracked or at maximum positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a spring assembly is used to provide restoring force on the manual control device, then the control behavior is improved and feedback is provided to the user, but non-uniform movements and 'stick-slip' effects occur due to lack of elasticity
Solution Approach 1:
The patent introduces an adjusting device that can dynamically shift the middle position of the spring assembly based on the actual position of the driven element. This dynamic adjustment allows the spring assembly to adapt to changing operating conditions, preventing stick-slip effects by ensuring the spring force always corresponds to the actual position, thereby resolving the contradiction between providing feedback and maintaining movement uniformity.
Solution Approach 2:
The patent implements a feedback mechanism where the position of the driven element is continuously monitored and used to adjust the middle position of the spring assembly. This feedback loop ensures that the restoring force provided by the spring assembly always matches the actual position, eliminating the stick-slip effects that occur when there is a mismatch between the spring position and the driven element position.
2Device complexity
If the middle position of the spring assembly is fixed, then the structure is simple, but steerability is lost when the spring assembly is at maximum positions or incorrectly tracked
Solution Approach 1:
The patent transforms the fixed middle position into a dynamic one that can be adjusted based on the driven element's position. The adjusting device allows the middle position to shift within a defined range, enabling the system to maintain steerability even when the spring assembly reaches its mechanical limits or experiences tracking errors, thus resolving the contradiction between structural simplicity and adaptability.
Solution Approach 2:
The patent changes the parameter of the spring assembly's middle position from a fixed value to a variable that can be adjusted within a certain range. This parameter change allows the system to adapt to different operating conditions and maintain steerability, resolving the contradiction between keeping the structure simple and ensuring adaptability.
3Reliability
If the spring assembly is displaced to shift the zero point, then non-uniform movements are prevented, but the device complexity increases due to the adjusting device
Solution Approach 1:
The patent replaces a complex active adjustment mechanism with a simpler passive mechanical adjustment device that uses the existing spring assembly's displacement to automatically shift the zero point. This substitution reduces device complexity while maintaining the reliability benefit of preventing non-uniform movements.
Solution Approach 2:
The adjusting device is designed to be self-actuating, using the displacement of the spring assembly itself to shift the zero point without requiring external power or complex control systems. This self-service approach maintains movement uniformity while minimizing the increase in device complexity.
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
This solution prevents non-uniform movements and maintains steerability by allowing deflection beyond maximum positions, reducing residual spring deflection and ensuring safe and controlled operation of the work machine.
Implementation Method 1
at least one return device in the form of one or more spring assemblies that are connected to the manual control device in this way ensure that the spring pack exerts a restoring force on the manual control unit when the spring pack is not in its middle position
Implementation Method 2
The adjusting device (12) has a self-locking gear by means of which backward movement of the adjusting device (12) is prevented
Implementation Method 3
at least one brake, in particular a magnetic particle brake
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention relates to a system for controlling a work machine, in particular a wheel loader, having at least one hand-held control device, in particular a joystick or steering wheel, at least one restoring device in the form of one or more spring assemblies, which are connected to the hand-held control device in such a way a restoring force is exerted upon the hand-held control device by the spring assembly when said spring assembly is not in the central position. An adjusting device which engages with the spring assembly such that an adjustment of the central position of the spring assembly can be carried out, is provided.