Cleaning Robot Rotatable Wheel Assembly for Stuck-State Escape
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Solution Overview
Problem
Conventional cleaning robots face challenges in detecting and escaping stuck states such as 'jammed', 'lifted', and 'object-caught' conditions due to limited sensor capabilities and reliance on spring force, which hinders their ability to navigate through various obstacles and environments effectively.
Innovation Solution
A cleaning robot equipped with a dual-wheel structure and advanced sensor system, including a current sensor, encoder, and tilt sensor, that allows for real-time position and angle measurement, enabling the robot to detect stuck states and adjust its height and wheel position to escape from such conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spring-based suspension is used to lift the wheel in lifted state, then the wheel can contact the floor, but sufficient contact force cannot be obtained and the robot cannot escape from the obstacle
Solution Approach 1:
The patent applies dynamics by making the wheel assembly movable rather than fixed. The wheel assembly can rotate between a first position (wheel contacting floor) and a second position (idler wheel contacting floor), allowing the system to dynamically adapt to different stuck states. This dynamic adjustment enables the robot to escape from obstacles by changing the contact configuration rather than relying solely on spring force magnitude.
Solution Approach 2:
The patent changes the parameter of wheel assembly position from fixed to variable. By rotating the wheel assembly between different positions, the system modifies the contact force distribution and contact point, enabling escape from stuck states where conventional spring-based systems fail to generate sufficient contact force.
2Reliability
If the wheel protrudes perpendicularly to escape lifted state, then the wheel can contact the floor, but it is impossible to escape from the jammed state of the side portion
Solution Approach 1:
The patent implements universality by designing the wheel assembly to perform multiple functions: it can protrude perpendicular to escape lifted states, rotate to different positions to escape jammed states of side portions, and adapt to various obstacle configurations. This multi-functional design allows a single mechanism to handle diverse stuck states that would otherwise require different specialized solutions.
Solution Approach 2:
The dynamic rotation capability of the wheel assembly enables it to transition between different orientations and positions, allowing the robot to escape from both lifted states (perpendicular protrusion) and jammed side portion states (rotated positions), thereby achieving versatility across multiple stuck state scenarios.
3Ease of operation
If the cleaning robot enters a narrow space of an obstacle, then it can clean under furniture, but the upper portion of the cleaning robot is jammed
Solution Approach 1:
The patent applies dynamics by enabling the wheel assembly to rotate between a first position and a second position. When the robot enters a narrow space and the upper portion becomes jammed, the wheel assembly can rotate to the second position where the idler wheel contacts the floor, providing an alternative support configuration that allows the robot to escape from the jammed state while maintaining access to narrow cleaning spaces.
4Device complexity
If sensors are not installed or only simple spring suspension is used, then the device complexity is low, but the robot cannot detect or escape from stuck states effectively
Solution Approach 1:
The patent implements self-service by enabling the robot to detect and escape from stuck states autonomously without requiring complex external sensor systems. The encoder mounted on the wheel assembly monitors wheel rotation and position, and the controller automatically determines stuck states and commands wheel assembly rotation to escape, allowing the system to self-diagnose and self-correct without additional sensors or manual intervention.
Solution Approach 2:
The patent applies feedback by using the encoder to monitor wheel assembly position and rotation, providing real-time information to the controller. The controller uses this feedback to determine whether the robot is in a stuck state and automatically commands the wheel assembly to rotate to an escape position, creating a closed-loop control system that enhances reliability without requiring complex external sensing.
Data Source
AI summary
A cleaning robot includes a main body and a drive unit to move the main body. The drive unit includes a plurality of motors to generate driving force; a plurality of wheels connected to one of the plurality of motors and rotating by driving force received from the one of the plurality of motors; and a driving frame to support the plurality of wheels, receive driving force from another motor among the plurality of motors, and rotate for changing positions of the plurality of wheels.