Self-levelling chassis with rectangular overturning line
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Solution Overview
Problem
Existing self-levelling chassis systems, such as those described in WO2020/096953 A1, rely on triangular overturning lines for stability, which can lead to lower machine stability and incorrect wheel contact detection due to lateral eccentric loads, causing potential overturning hazards.
Innovation Solution
A multi-function self-levelling chassis with a rectangular overturning line configuration, utilizing rockers connected to rotating axles and actuators, along with tilt sensors and relative position sensors, to maintain the central unit level within ±0.5° and ensure all four wheels remain in contact with the ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are installed in hydraulic actuators to detect wheel ground contact, then wheel contact status can be monitored, but lateral eccentric loads cause incorrect readings leading to false detection
Solution Approach 1:
The patent replaces the mechanical pressure sensor system with an optical detection system. Cameras mounted on the chassis capture images of the ground and wheels, and image processing algorithms determine wheel contact status. This substitution eliminates the problem of lateral eccentric loads affecting mechanical pressure sensors, as optical detection is not influenced by such mechanical forces.
Solution Approach 2:
The patent introduces an intermediary optical system (cameras and image processing) between the wheel-ground interaction and the control system. Instead of directly measuring force through pressure sensors that are susceptible to eccentric loads, the system uses visual information as an intermediary to infer contact status, thereby eliminating the direct mechanical measurement problem.
2Device complexity
If triangular overturning lines are used for self-levelling, then the system can function with simpler geometry, but machine stability decreases and overturning risk increases
Solution Approach 1:
The patent transitions from symmetric triangular overturning lines to asymmetric rectangular configuration. The rectangular arrangement of wheels creates four distinct overturning lines (front-left, front-right, rear-left, rear-right) rather than the three lines in a triangular configuration. This asymmetric rectangular geometry provides broader overturning lines and greater stability while maintaining manageable system complexity through systematic control of each wheel's position.
3Stability of the object's composition
If rectangular overturning line configuration is implemented, then machine stability and traction are improved, but the system complexity increases compared to triangular configuration
Solution Approach 1:
The patent segments the levelling control into four independent wheel control units, each with its own actuator and optical detection. Rather than attempting to control the entire rectangular chassis as a single unit, the system divides it into four manageable segments (one per wheel), allowing independent position control. This segmentation reduces the overall system complexity by making each control unit simpler while achieving the stability benefits of the rectangular configuration.
Solution Approach 2:
The patent implements dynamic adjustment of each wheel's position independently to maintain the rectangular overturning line configuration. The control system continuously monitors wheel positions through optical detection and adjusts actuators in real-time to keep all four wheels in contact with the ground and maintain rectangular geometry. This dynamic adaptation allows the system to maintain stability on varying terrain without requiring a fixed, complex mechanical structure.
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
The system provides enhanced stability and accurate wheel contact detection, reducing the risk of overturning and ensuring consistent traction on sloping or rough terrain by maintaining a rectangular overturning line configuration and using redundant sensor systems for reliable data.
Implementation Method 1
tilt sensors and relative position sensors, to maintain the central unit level within ±0.5°
Implementation Method 2
Each box is attached to the central part by a horizontal-longitudinal axle to allow for relative rotation between the two. In turn, the central part also has another rotating axle to connect it to the end of the corresponding actuator, which may be electric, hydraulic, or pneumatic.
Implementation Method 3
two rockers fitted lengthways are connected, one at the front and another at the back, both jointed to the central unit using respective horizontal and transverse rotating axles
Implementation Method 4
One or two pressure sensors are installed in each hydraulic actuator, which indirectly measure the pressure applied on the ground by each of the wheels.
Data Source
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AI summary
The chassis of the invention includes a levelling system with a configuration in which the overturning lines generated by the layout of the wheels remain a rectangle formed by the points where the wheels are touching the supporting ground, allowing for the central unit to remain levelled within certain pre-set limits. The chassis is made up of a central unit 30, with an upper flange 33 bolted to the superstructure to be dynamically levelled, to which two rockers 10 and 20 are jointed, controlled by actuators 60-80 that level the X-axis and actuators 79-90 that level the Y-axis. The rockers are connected to the front and rear axles 50 and 40 that, in turn, are connected to the wheels 2-3-4-5 by a central part 57-47 and jointed boxes 55-56 and 45-46, also assisted by actuators 41-43 and 42-44, which have a tilt sensor 104 connected to a control PLC 103 that controls the actuators by reading the sensors giving the relative position between the different parts.