Magnetic Obstacle Sensing for Autonomous Device Shell Deflection
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Solution Overview
Problem
Conventional obstacle detection systems for autonomous devices, such as robotic mowers, often rely on mechanical switches, capacitive sensors, and multiple magnets, which can be unreliable, sensitive to placement, and affected by environmental conditions like moisture and dirt.
Innovation Solution
A sensor system comprising a single three-axis magnetic flux sensor mounted on the chassis and a magnet attached to a resiliently mounted shell, allowing the sensor to output a three-axis magnetic flux vector indicative of the direction and magnitude of the shell's movement relative to the chassis, enabling effective obstacle detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical switches and capacitive sensors are used for obstacle detection, then the system can detect obstacles, but the system becomes unreliable and sensitive to environmental conditions
Solution Approach 1:
The patent replaces mechanical switches and capacitive sensors with a magnetic sensing system. A magnet is attached to the resilient shell while a magnetic flux sensor is mounted on the chassis. When the shell contacts an obstacle and deflects, the magnet moves relative to the sensor, generating a magnetic flux change that is detected and processed to identify the obstacle. This substitution eliminates the reliability issues and environmental sensitivity of mechanical and capacitive systems.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the shell movement and the detection system. The magnet attached to the shell creates a magnetic field that couples the mechanical deflection to the magnetic flux sensor without requiring direct mechanical contact or electrical connections that are sensitive to environmental conditions. This intermediary field transmission provides reliable detection while isolating the system from harmful environmental factors.
2Measurement precision
If multiple magnets are used in the detection system, then the detection coverage is improved, but the device complexity and cost increase
Solution Approach 1:
The patent merges the functions of multiple magnets into a single magnet by using a three-axis magnetic flux sensor. Instead of placing multiple magnets at different locations and using multiple single-axis sensors, the invention uses one magnet with a three-axis sensor that can detect magnetic flux changes in all three spatial dimensions. This combination maintains detection accuracy while significantly reducing device complexity and component count.
Solution Approach 2:
The patent transitions from a single-axis detection approach to a three-dimensional detection approach. By using a three-axis magnetic flux sensor, the system can detect magnetic flux changes along the X, Y, and Z axes simultaneously. This dimensional expansion allows a single magnet-sensor pair to provide the same detection coverage and precision that would otherwise require multiple magnets arranged in space.
3Device complexity
If mechanical switches are used for obstacle detection, then the system structure is simple, but the system becomes unreliable and requires frequent maintenance
Solution Approach 1:
The patent replaces the mechanical switch system with a magnetic sensing system that has no moving parts or contact points. The magnet attached to the shell interacts with the magnetic flux sensor through the magnetic field, eliminating mechanical wear, contact degradation, and the need for adjustment. This substitution maintains structural simplicity while dramatically improving reliability and reducing maintenance requirements.
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 provides reliable and efficient obstacle detection for autonomous devices, allowing them to accurately determine the location and direction of obstructions and navigate around them effectively, while being cost-effective and less prone to environmental interference.
Implementation Method 1
a sensor assembly comprising a single sensor disposed on the chassis and a magnet disposed on and movable with the shell in response to the force applied to the shell, wherein the sensor is configured to output a three-axis magnetic flux vector in response to a movement of the magnet
Data Source
AI summary
An obstruction sensing system for an autonomous device can include a chassis including a drive system for movement relative to a working surface, a shell resiliently mounted to the chassis and movable relative to the chassis in response to a force applied to the shell, a sensor assembly comprising a single sensor disposed on the chassis and a magnet disposed on and movable with the shell in response to the force applied to the shell, wherein the sensor is configured to output a three-axis magnetic flux vector in response to a movement of the magnet. A sensing method for an autonomous device can include detecting a polarity change in the sensor and in response determining that an obstruction has been detected, evaluating, by a processing component, a three-axis magnetic flux vector, and calculating at least one of a direction and a magnitude of a deflection based on the evaluation.