Center Pivot Axle Control for Straight Course Stability
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Solution Overview
Problem
Riding power equipment, such as mowers, tend to swerve on irregular ground surfaces due to changes in camber angles, requiring constant operator intervention to maintain a straight course, which reduces work efficiency and operator comfort.
Innovation Solution
The implementation of a center pivot axle system with a control unit that adjusts the rotational speeds of driven wheels based on detected roll angles and steering inputs, allowing the equipment to maintain a straight course without operator intervention by compensating for camber angle changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a center pivot axle system is used to accommodate ground irregularities, then the equipment can travel over bumps and dips without wheel lift, but the camber angle changes cause the vehicle to swerve and require constant operator steering input
Solution Approach 1:
The control unit automatically detects camber angle changes via the camber sensor and adjusts the driven wheel rotational speeds to compensate for swerving, eliminating the need for operator intervention. The system serves itself by autonomously counteracting the steering tendency caused by camber angle changes.
Solution Approach 2:
The camber sensor continuously monitors the camber angle of the non-driven wheels and provides feedback to the control unit. The control unit uses this feedback to dynamically adjust the rotational speeds of the driven wheels, creating a closed-loop control system that maintains straight travel despite ground irregularities.
2Stability of the object's composition
If the operator constantly steers to compensate for swerving, then the vehicle can maintain a straight course, but the operator's attention is required continuously and comfort is impaired
Solution Approach 1:
The control system automatically maintains straight course by detecting camber angle changes and adjusting driven wheel speeds accordingly, freeing the operator from continuous steering attention and improving comfort.
Solution Approach 2:
The manual mechanical steering operation is replaced by an automated electronic control system that uses sensor data to dynamically adjust wheel speeds, substituting operator action with an automated control mechanism.
3Stability of the object's composition
If individual wheel speed control is implemented to compensate for camber changes, then straight travel is maintained, but the device complexity increases with sensors and control units
Solution Approach 1:
The control unit performs multiple functions: it monitors camber angle via the sensor, calculates the appropriate speed differential, and controls the rotational speeds of the driven wheels. This multi-functionality reduces the need for separate dedicated components for each control task.
4Device complexity
If the axle is rigidly attached to the vehicle body, then the structure is simple and robust, but one wheel may be lifted from the ground when traveling on irregular surfaces
Solution Approach 1:
The axle system transitions from a static rigid attachment to a dynamic configuration where the non-driven wheels can pivot relative to the vehicle body via the center pivot. This dynamic adjustment allows the wheels to adapt to ground irregularities while maintaining ground contact.
Data Source
AI summary
Power equipment such as a riding mower 2 is provided with a center pivot axle 16 for non-driven wheels 9 thereof and a rigid axle 14 for driven wheels 8. A control unit 1 of the power equipment is configured to accelerate the left driven wheel when a right end up roll angle of the center pivot axle is detected by an axle sensor 25, and to accelerate the right driven wheel when a left end up roll angle of the center pivot axle is detected by the axle sensor when substantially no steering input of a steering device 22 is detected by a steering sensor 24 so that the power equipment may maintain a straight course.