Excavator Safety System Using Distance Sensors and Slewing Angle Feedback
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Solution Overview
Problem
Construction machinery with a lower travelling body and an upper slewing body faces challenges in accurately detecting entry prohibited areas due to the difficulty in attaching multi-lens cameras, which can be affected by environmental conditions and slewing angles, leading to inaccurate cliff edge detection and travel stop commands.
Innovation Solution
The implementation of distance detection means and a slewing angle detector on the upper slewing body, combined with a controller that generates safety information based on the travelling direction of the lower travelling body, allowing for accurate detection and output of safety information regardless of the slewing angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the multi-lens camera is attached to the lower travelling body, then the detection direction can be aligned with the travelling direction, but the camera is exposed to water and earth/sand causing early deterioration
Solution Approach 1:
The patent introduces the upper slewing body as an intermediary carrier for the detection device. Instead of directly attaching the camera to the lower travelling body (which causes deterioration from water and sand), the camera is mounted on the upper sleving body, which rotates independently. This mediator position protects the camera while still enabling detection of the lower travelling body's movement through angle sensing.
2Measurement precision
If the multi-lens camera is attached to the lower travelling body, then the detection direction aligns with travelling direction, but electrical connection requires slip ring complicating structure
Solution Approach 1:
The upper slewing body serves as an intermediary platform that carries both the detection device and the angle sensor. This configuration allows electrical connections to be made at the upper body level (which rotates as a unit) rather than requiring slip rings between the stationary lower body and the rotating camera assembly, thereby simplifying the electrical connection structure.
3Reliability
If the multi-lens camera is provided on the upper sleving body, then the camera is protected from environmental conditions, but the detection direction does not align with travelling direction due to sleving angle
Solution Approach 1:
The patent implements a feedback mechanism using an angle sensor to detect the slewing angle of the upper sleving body. This angle information is fed back to the controller, which uses it to calculate and adjust the position of the entry prohibited area on the display. This feedback loop compensates for the slewing angle deviation, ensuring that the detection direction remains accurately aligned with the travelling direction regardless of the upper body's rotational position.
4Device complexity
If the sleving angle is not compensated, then the system structure remains simple, but the entry prohibited area cannot be accurately specified
Solution Approach 1:
The patent employs feedback through angle sensing and computational correction. Rather than adding complex mechanical compensation mechanisms, the system uses an angle sensor to detect slewing angle and a controller to computationally adjust the entry prohibited area position based on this feedback, achieving high detection accuracy with relatively simple system structure.
Data Source
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AI summary
A hydraulic excavator (1) includes a lower travelling body (2), an upper slewing body (3) attached to the lower travelling body (2) in a rotatable manner about a slewing axis (C), distance sensors (14A to 14D) attached to the upper slewing body (3), the distance sensors being capable of detecting a distance to an object to be detected, the object being located in a circumference of the lower travelling body (2) about the slewing axis (C); a slewing angle sensor (15) that detects a slewing angle of the upper slewing body (3) with respect to the lower travelling body (2); and a controller (16) that specifies an entry prohibited area (EH) in which ingress of the lower travelling body (2) is prohibited, based on the distance detected by the distance sensors (14A to 14D), that generates information about safety with reference to a travelling direction of the lower travelling body (2) based on the entry prohibited area (EH) and the slewing angle detected by the slewing angle sensor (15), and that outputs the information.