Work Vehicle Sensor Switching for Adverse Weather Obstruction Avoidance
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Solution Overview
Problem
Work vehicles equipped with both laser radars and ultrasonic sensors struggle to effectively avoid obstructions during mist or rain conditions due to the reduced detectable distance of ultrasonic sensors, leading to potential collisions when vehicle speed is not adequately reduced.
Innovation Solution
A work vehicle system that includes a vehicle body, obstruction detectors for both laser radars and ultrasonic sensors, a measurement environment determiner to assess conditions, and a vehicle speed manager to adjust speed based on sensor performance, allowing the vehicle to travel at a slower speed when conditions are adverse, ensuring safe obstruction avoidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ultrasonic sensor is used to detect obstructions during mist or rain conditions, then the vehicle can avoid erroneous detection from fog drops or rain drops, but the detectable distance becomes shorter compared to laser radar
Solution Approach 1:
The system changes the operating parameters by switching between laser radar and ultrasonic sensor based on environmental conditions (mist, rain, fog). When adverse conditions are detected, the system transitions from laser radar to ultrasonic sensor, accepting reduced detection distance in exchange for reliable operation-free detection.
Solution Approach 2:
An environment detection mechanism acts as an intermediary to monitor weather conditions and trigger the switch between detection systems. This intermediary component enables the system to adaptively select the appropriate sensor based on external environmental factors.
2Productivity
If the vehicle travels at normal speed during adverse weather conditions, then productivity is maintained, but the vehicle cannot stop in time to avoid obstructions detected by ultrasonic sensor with limited range
Solution Approach 1:
The vehicle speed is made dynamic rather than fixed. The travel control unit automatically adjusts the speed limit based on the active detection system's capabilities. When ultrasonic sensor is active, the system enforces a lower speed threshold to ensure the vehicle can stop within the sensor's limited detection range, while allowing higher speeds when laser radar is operational.
3Length of stationary object
If laser radar is used to detect obstructions, then the detectable distance is extended, but erroneous detection occurs when laser beams are reflected by fog drops or rain drops
Solution Approach 1:
The environment detection mechanism serves as an intermediary that monitors weather conditions and prevents the laser radar from operating under adverse conditions. This intermediary triggers a switch to ultrasonic sensor when mist, rain, or fog is detected, eliminating erroneous detections while maintaining long-range detection capability when conditions are favorable.
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 ensures reliable obstruction collision avoidance by switching to a slower speed when environmental conditions deteriorate, allowing the ultrasonic sensors to detect and prevent collisions, even when laser radar performance is compromised.
Implementation Method 1
Laser beams used in the laser radars can advance straight ahead to detect an obstruction at a remote position. However, laser beams can be reflected by fog drops
Implementation Method 2
a second obstruction detector configured to detect the obstruction based on a sensor signal from an ultrasonic sensor unit
Data Source
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AI summary
A work vehicle includes a vehicle body, a first obstruction detector configured to detect an obstruction based on a radar signal from a laser radar unit, a second obstruction detector configured to detect the obstruction based on a sensor signal from an ultrasonic sensor unit, a measurement environment determiner configured to determine whether a measurement environment around the laser radar unit is normal, a vehicle speed manager configured to manage a first vehicle speed allowing, in response to obstruction detection by the first obstruction detector, the vehicle body to stop in front of the obstruction, and a second vehicle speed allowing, in response to obstruction detection by the second obstruction detector, the vehicle body to stop in front of the obstruction, the second vehicle speed being slower than the first vehicle speed, and a travel controller configured to cause, while the vehicle body is caused to travel at the first vehicle speed, when the measurement environment determiner determines that the measurement environment is abnormal, the vehicle body to travel at the second vehicle speed.