Mobile Robot Bumper Sensors for Precise Contact Force Detection
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Solution Overview
Problem
Existing mobile robots rely on mechanical switches for obstacle detection, which provide binary feedback and are not sensitive enough to accurately determine the location, magnitude, and duration of forces applied to bumpers, limiting their navigational adjustments and increasing the risk of getting stuck.
Innovation Solution
The use of capacitive, inductive, or Hall effect sensors that detect movement of the bumper relative to the chassis, generating electrical signals proportional to displacement, allowing for the determination of force attributes such as location, magnitude, and duration, enabling more precise navigational adjustments and reducing the likelihood of getting stuck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical switches are used for obstacle detection, then the device structure is simple, but the measurement precision of force attributes is insufficient
Solution Approach 1:
The patent replaces mechanical switches with capacitive sensors that use electrical fields instead of mechanical contact. The capacitive sensor includes a first plate connected to the bumper and a second plate connected to the chassis, forming a capacitor that detects bumper displacement through changes in capacitance. This substitution eliminates the need for mechanical contact while providing continuous, high-resolution measurement of force attributes including location, magnitude, and duration.
2Loss of information
If mechanical switches provide binary feedback, then the device complexity is low, but the information completeness about force attributes is limited
Solution Approach 1:
The capacitive sensor provides continuous feedback about bumper displacement rather than binary on/off signals. The controller receives real-time capacitance values that reflect the instantaneous position of the bumper, enabling determination of force location, magnitude, and duration. This continuous feedback mechanism allows the robot to make nuanced navigational adjustments based on detailed force attribute information.
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 sensor system provides high sensitivity and accuracy in detecting forces, allowing the robot to adjust its navigation effectively and reduce the number of visible movable components, improving its operational reactivity and avoiding obstacles with greater precision.
Implementation Method 1
each sensor may be a capacitive sensor having one plate movably mounted so that the plate moves along with the bumper relative to the chassis, and another plate mounted so that it is stationary relative to the chassis. Movement of one plate relative to another, due to the movement of the bumper, causes the capacitive sensor to output an electrical signal having a magnitude or value proportional to the distance between the plates.
Implementation Method 2
each sensor may be a Hall effect sensor having a magnet movably mounted so that the magnet moves along with the bumper relative to the chassis, and the Hall effect sensor mounted so that it is stationary relative to the chassis
Implementation Method 3
each sensor may be an inductive sensor having a coil movably mounted so that the coil moves along with the bumper relative to the chassis, and the core mounted so that it is stationary relative to the chassis
Data Source
AI summary
A robot includes a body and a bumper. The body is movable relative to a surface and includes a first portion of a sensor. The bumper is mounted on the body and movable relative to the body and includes a backing and a second portion of the sensor. The backing is movable relative to the body in response to a force applied to the bumper. The second portion of the sensor is attached to the backing and movable with the backing relative to the first portion of the sensor in response to a force applied to the bumper. The sensor is configured to output an electrical signal in response to a movement of the backing. The electrical signal is proportional to an amount of displacement of the second portion relative to the first portion.