Lawnmower Steering Assist Using IMU Feedback on Uneven Terrain
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lawnmowers often deviate from desired paths due to gravitational and terrain forces, leading to undesirable steering effects such as veering downhill or turning on bumpy surfaces, necessitating improved assisted steering systems for precise and efficient control.
Innovation Solution
A lawnmower system incorporating an inertial measurement unit (IMU) and a controller that adjusts motor speed based on user input and gain profiles to counteract deviations, using varying scale factors for different steering inputs to maintain direction and allow quick turns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional steering control is used without assistance, then the system complexity is low, but the lawnmower deviates from desired path due to gravitational and terrain forces
Solution Approach 1:
The steering control system receives feedback from the inertial measurement unit (IMU) about actual lawnmower orientation and compares it to the desired orientation derived from user input. The controller adjusts motor commands based on this feedback loop to counteract gravitational and terrain forces, maintaining accurate path following despite external disturbances.
Solution Approach 2:
The patent replaces traditional mechanical steering linkages with an electrically-controlled system using independent motor control. Each wheel's motor speed is independently adjusted via electronic control based on IMU feedback, substituting mechanical force transmission with electrical actuation and electronic control algorithms.
2Reliability
If high steering assistance is applied to counteract terrain forces, then path accuracy improves, but the responsiveness to user steering inputs decreases
Solution Approach 1:
The steering assistance level is dynamically adjusted based on operating conditions. The controller monitors user steering inputs and terrain conditions, modulating the strength of corrective actions. When user input indicates intentional steering changes, the system reduces assistance to maintain responsiveness; when user input is minimal, the system applies stronger correction to counteract terrain forces.
Solution Approach 2:
The control system varies parameters such as the gain factor applied to IMU feedback and the threshold for detecting user intent. By dynamically changing these control parameters based on operating context, the system optimizes the balance between path accuracy and steering responsiveness, preventing over-correction while maintaining stability.
3Adaptability or versatility
If the lawnmower traverses slopes, then operational versatility is improved, but gravitational force causes downhill turning
Solution Approach 1:
The control system applies preliminary counteracting forces before the lawnmower significantly deviates from the desired path on slopes. By continuously monitoring IMU data and predicting gravitational influence based on terrain angle, the system proactively adjusts motor commands to prevent downhill turning, rather than merely reacting after deviation occurs.
4Adaptability or versatility
If the lawnmower traverses bumpy ground, then operational versatility is improved, but wheel bumps cause unwanted turning
Solution Approach 1:
The IMU provides continuous feedback about lawnmower orientation changes caused by wheel bumps on irregular terrain. The controller processes this feedback in real-time, distinguishing between intentional user steering inputs and unwanted turns caused by terrain irregularities, and applies appropriate corrective motor commands to maintain desired path.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A lawnmower including: a wheel; a motor operably coupled to drive the wheel; a user input configured to receive a steering control input from a user; and a controller configured to operate in a steering assist mode where the controller: receives information from the user input, the information including a position of the user input; compares the position of the user input to a gain profile saved in a memory of the controller; determines a scale factor from the gain profile based on the comparison; generates a command instruction to control a speed of the motor based on the position of the user input and the determined scale factor; and transmits the command instruction to the motor to affect a speed of the motor.