Inertial Yaw Sensor Traction Control for Articulated Machines
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Solution Overview
Problem
Conventional machine control systems fail to accurately account for natural wheel speed differences during steering or turning, leading to inadequate traction control, particularly in articulated vehicles where articulation-induced speed differences are significant, resulting in wheel spin and slip issues.
Innovation Solution
A system that includes wheel speed sensors, an orientation sensor for yaw rate measurement, and differential clutches with actuators, which produce corner speed estimates and target speed signals to optimize wheel speed control, converting wheel speed errors into clutch control signals to manage torque distribution effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional open differential is used to accommodate wheel speed differences during articulation, then steering flexibility is maintained, but wheel spin and slip increase during acceleration and deceleration
Solution Approach 1:
The differential clutch engagement is dynamically controlled based on real-time wheel speed measurements and articulation rate signals. The system automatically adjusts clutch engagement pressure to equalize wheel speeds during acceleration and deceleration while allowing speed differences during steady-state turning, resolving the contradiction between steering flexibility and traction control
Solution Approach 2:
The system uses wheel speed sensors and articulation rate sensors to provide continuous feedback to the control unit. This feedback enables the control unit to adjust differential clutch engagement in real-time, detecting wheel spin or slip conditions and responding by increasing clutch pressure to equalize wheel speeds, thereby improving reliability without compromising steering flexibility
2Reliability
If differential clutch is engaged to reduce wheel spin and slip, then traction control improves, but steering capability deteriorates
Solution Approach 1:
The system dynamically adjusts the degree of differential clutch engagement based on operating conditions. During steady-state turning, the clutch remains disengaged or lightly engaged to maintain steering capability. During acceleration or deceleration when wheel spin or slip is detected, the clutch engagement pressure is increased to equalize wheel speeds, thus improving traction control without permanently compromising steering capability
Solution Approach 2:
The control system periodically monitors wheel speeds and articulation rates, adjusting clutch engagement in periodic cycles. This periodic control allows the system to temporarily engage the clutch only when needed for traction control while maintaining steering flexibility during normal operation, resolving the contradiction between improved traction and preserved steering capability
3Measurement precision
If wheel speed sensors and control systems are added to manage articulation-induced speed differences, then traction control accuracy improves, but device complexity increases
Solution Approach 1:
The control unit serves multiple functions: it processes wheel speed sensor signals, processes articulation rate sensor signals, determines actual wheel speeds by compensating for articulation effects, and controls the differential clutch engagement. This multi-functionality consolidates what would otherwise be separate systems into a single control unit, improving measurement precision without proportionally increasing device complexity
Solution Approach 2:
The control unit acts as an intermediary that receives raw sensor data from wheel speed sensors and articulation rate sensors, processes this information to calculate actual wheel speeds, and generates appropriate control signals for the differential clutch. This intermediary processing layer enables accurate traction control by separating the measurement function from the control function, managing complexity through modular architecture
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
The system enhances traction control by accurately managing wheel speed differences during steering and turning, reducing wheel spin and slip, and improving overall mobility and steering performance in various terrain conditions.
Implementation Method 1
an inertial sensor responsive to a yaw rate of the machine from which a yaw rate signal is derived
Data Source
AI summary
An electronic traction optimization system includes a control unit adapted to produce a corner speed estimate signal for each wheel of a machine, produce an ideal target speed signal for each wheel having a value at least partially responsive to the corner speed estimate signals, produces a practical target speed signal for each wheel, generates an actual target speed signal having a value responsive to a comparison of the ideal target speed signal and the practical target speed signal for each wheel. The control unit compares each actual target speed signal to an associated wheel speed signal to obtain a wheel speed error signal for each wheel and converts each wheel speed error signal to a clutch control signal, wherein each differential clutch actuator is responsive to an associated clutch control signal.