Wheel Loader Obstacle Sensing With Position-Based Sensor Switching
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Solution Overview
Problem
Wheel loaders face challenges in accurately measuring the distance to front obstacles during loading or dumping operations due to limited driver visibility and obstruction by the lifted work apparatus, especially when performing unmanned automation tasks.
Innovation Solution
A control system for wheel loaders that includes upper and lower sensors, such as LiDAR or stereo cameras, and radar/ultrasonic sensors, which dynamically switch the primary sensor based on the work apparatus's position to ensure accurate obstacle detection, with the upper sensor used when the apparatus is low and the lower sensor used when it is raised.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the work apparatus is lifted to perform loading operations, then the loading capability is improved, but the driver's front view is blocked and obstacle detection becomes difficult
Solution Approach 1:
The obstacle detection system is segmented into multiple sensors positioned at different locations (upper sensor in driver cabin, lower sensor on front body) to detect obstacles in different spatial zones. This segmentation allows continuous obstacle detection regardless of the work apparatus position.
Solution Approach 2:
Sensor data processing and fusion acts as an intermediary between the physical sensors and the control system. The obstacle detection control device processes data from multiple sensors and selects appropriate data based on work apparatus position, mediating the transition between different detection modes.
2Device complexity
If a single sensor is used for obstacle detection, then the device complexity is reduced, but the measurement accuracy varies with work apparatus position
Solution Approach 1:
The sensor selection is made dynamic based on the work apparatus position. The obstacle detection control device dynamically selects which sensor data to use (upper or lower sensor) according to the detected boom position, ensuring optimal measurement accuracy for each operational state.
Solution Approach 2:
Multiple sensors are configured to perform the same obstacle detection function but from different positions and angles. Both the upper sensor in the driver cabin and the lower sensor on the front body can detect obstacles, providing universal obstacle detection capability across different work apparatus positions.
3Area of stationary object
If the upper sensor is used for obstacle detection, then the detection range is improved, but the sensor becomes obscured when the work apparatus is in high position
Solution Approach 1:
Different sensors are assigned to detect different spatial zones based on their local advantages. The upper sensor detects obstacles in the upper detection zone when the work apparatus is low, while the lower sensor detects obstacles in the lower detection zone when the work apparatus is high, optimizing detection reliability for each local condition.
Data Source
AI summary
A control system for a wheel loader includes an upper sensor installed in a driver cabin to obtain shape information data for an object in front of the driver cabin, a lower sensor installed in a front body to obtain shape information data for an object in front of the front body, a work apparatus position detection portion configured to detect a position of a work apparatus connected rotatably to the front body, and an obstacle detection control device configured to receive the shape information data from the upper sensor and the lower sensor and configured to calculate a distance to the object based on the information data of any one selected from the upper sensor and the lower sensor according to the detected position of the work apparatus.