Robot Lawnmower Motor Block Obstacle Detection With Impact Damping
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Solution Overview
Problem
Existing robot lawnmowers with fixed covers face challenges in efficiently detecting obstacles, leading to potential damage and unpleasant impacts, as they rely on costly and complex mechanisms or skidding wheels, and struggle to quickly respond to impacts without damaging the yard.
Innovation Solution
A robot lawnmower design featuring a base frame with a fixed cover, driven wheels, and an elastic motor block that rotates upon impact, allowing for rapid detection and response through sensors and a control unit, which reverses motion and blocks the blade, utilizing elastic means for damping and quick recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a movable cover with spring means and sensors is used to detect obstacles, then obstacle detection capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the obstacle detection function from the cover structure and relocates it to the motor block. The motor block becomes the sensing element itself, detecting obstacles through current readings, while the cover remains simple and fixed. This separation simplifies the overall structure while maintaining detection capability.
Solution Approach 2:
The motor block serves dual functions: driving the wheel and detecting obstacles. The existing motor components (current sensors, control circuitry) are utilized for obstacle detection without adding separate dedicated sensing mechanisms, making the system self-sufficient and reducing complexity.
2Reliability
If a movable cover with magnets and sensors is used to detect obstacles, then obstacle detection capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the complex movable cover mechanism with magnets and sensors, extracting only the essential detection function and implementing it through the motor's existing current sensing capabilities. This eliminates the need for separate magnetic sensors and movable cover components, reducing manufacturing cost.
Solution Approach 2:
The patent uses the motor's existing current sensing infrastructure, which is already present and inexpensive, rather than adding expensive dedicated obstacle detection sensors. The solution leverages existing components to achieve detection functionality economically.
3Reliability
If reading current on driving motors is used to detect impact, then obstacle detection is achieved, but impact force is significant causing wheel skidding and yard damage
Solution Approach 1:
The patent introduces a resilient element between the motor block and the wheel hub that acts as a cushion before impact occurs. This elastic component absorbs impact energy, allowing the motor block to rotate relative to the wheel, reducing the transmitted impact force to the ground and preventing wheel skidding and yard damage.
Solution Approach 2:
The resilient element serves as an intermediary between the motor block and the wheel hub, mediating the impact forces. It allows relative rotation to occur, detecting obstacles while cushioning the impact, thus protecting the yard from damage and preventing wheel skidding.
4Device complexity
If a fixed cover is used, then device complexity is reduced, but obstacle detection response speed decreases and impact is more significant
Solution Approach 1:
The patent introduces dynamic capability to the motor block through the resilient element, allowing it to rotate relative to the wheel hub during impact. This dynamic response enables fast obstacle detection while maintaining a simple fixed cover structure, resolving the contradiction between simplicity and response speed.
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 enables faster and more effective obstacle detection and response, preventing damage and skidding, while being simple to assemble and maintain, with the elastic means providing dual functionality in blocking wheels and damping impacts, allowing the lawnmower to quickly resume operation in a different direction.
Implementation Method 1
the absorbing means comprise elastic means adapted to keep the motor block in a position of equilibrium with respect to the bracket in the absence of bumps
Implementation Method 2
at least one sensor fixed to the base frame and adapted to detect said rotation of the motor block with respect to the base frame
Data Source
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AI summary
There is described a robot lawnmower (1) comprising a base frame (2), a cover integral with the base frame (2), two driving wheels (3) and at least one directional idler wheel (4), wherein each driving wheel (3) is driven by an electric motor (5). Each motor (5) comprises a motor block (55) rotatably fixed to a bracket (7) to which the respective driving wheel (3) is rotatably fixed. The robot lawnmower (1) comprises absorbing means (56, 57, 61) of a bump of the robot lawnmower (1). The absorbing means (56, 57, 61) are adapted to allow the rotation of the motor block (55) with respect to the base frame (2) in the case of a bump in the direction of motion of the robot lawnmower (1).