Cleaning Robot Wheel Structure for Stuck State Escape
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Solution Overview
Problem
Conventional cleaning robots lack effective mechanisms to detect and escape from stuck states such as 'jammed', 'lifted', and 'object-caught' conditions due to limited sensor capabilities and reliance on spring forces, which hinder their ability to navigate complex environments.
Innovation Solution
A cleaning robot equipped with a wheel structure that includes a main wheel and a sub wheel, a driving frame that can change position, and sensors like current sensors and tilt sensors to detect stuck states and adjust the robot's height to escape, using a controller to determine the type and risk level of the stuck state and implement appropriate escape maneuvers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spring-based suspension is used to allow wheel protrusion, then the robot can escape from lifted state, but sufficient contact force cannot be obtained when wheel is lifted and it is difficult to escape from obstacle
Solution Approach 1:
The wheel assembly is designed with a rotatable driving frame that can dynamically change the position and orientation of wheels in response to detected stuck states. When a lifted state is detected, the driving frame rotates to protrude the idle wheel downward, providing both contact force and escape capability simultaneously.
2Force
If wheel protrudes perpendicularly to escape lifted state, then contact force is improved, but it is impossible to escape from jammed state of side portion
Solution Approach 1:
The driving frame can rotate to different angles depending on the type of stuck state detected. For side jammed states, the frame rotates to protrude wheels laterally; for lifted states, it rotates to protrude wheels downward. This dynamic adaptability allows escape from multiple stuck state types.
Solution Approach 2:
The same wheel assembly structure with rotatable driving frame serves multiple functions: escaping from lifted states, escaping from side jammed states, and maintaining stable contact on inclined surfaces. The system universally handles various stuck state types through a single multi-functional mechanism.
3Device complexity
If no height reduction function is provided, then structure is simple, but robot cannot escape from jammed state of upper portion
Solution Approach 1:
The driving frame can rotate to reduce the total height of the robot by bringing the main body closer to the ground. When upper portion jammed state is detected, the frame rotates to lower the robot's profile, allowing escape from narrow spaces under furniture or appliances.
4Device complexity
If current sensor method is used to detect stuck state, then detection is simple, but it cannot be applied to various situations and is not reliable
Solution Approach 1:
The encoder serves multiple detection functions: detecting stuck states, determining robot orientation (upside down or sideways), and monitoring wheel rotation. This multi-functional sensor approach replaces multiple specialized sensors while improving reliability through cross-validation of detection data.
Solution Approach 2:
The system continuously monitors encoder data and compares actual wheel rotation against expected rotation based on motor commands. When discrepancies indicate a stuck state, the system provides feedback to trigger escape maneuvers, creating a closed-loop control system that adapts to various situations.
Data Source
AI summary
A cleaning robot having improved traveling performance and a method of controlling the same. The cleaning robot detects a stuck state such as a ‘jammed state’, ‘lifted state’, or ‘object-caught state’ by using a motion instruction or sensor information and quickly escapes from the stuck state caused in various traveling conditions by using a wheel structure capable of changing a total height of the cleaning robot. In addition, a degree of risk and type of the stuck state is predicted before the cleaning robot is in the stuck state so that the cleaning robot may deal with the stuck state in advance. The cleaning robot may escape from the stuck state via rapidly deceleration or quick stopping in accordance with the predicted degree of risk of the stuck state, and the cleaning robot may efficiently deal with the stuck state by using information to select an escaping method suitable for the type of the stuck state.