Differential Wheel Speed Control for Straight-Line Transition
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Solution Overview
Problem
Existing electric work vehicles face challenges in reducing deviation from a target line when transitioning from a turning state to a straight-ahead state.
Innovation Solution
A vehicle control system that independently controls left and right drive wheels using manipulators and a controller to adjust rotational speeds based on target and command rotational speed differences, setting one speed differently when the difference exceeds a predetermined value to reduce yaw rate and centrifugal force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the target rotational speed difference is reduced to reduce yaw rate, then the deviation from target line is reduced, but the turning performance deteriorates
Solution Approach 1:
The control system dynamically adjusts the command rotational speed based on the vehicle state. During turning, the system maintains larger rotational speed differences for better turning performance, while during straight-ahead transition, it reduces the rotational speed difference to minimize deviation from target line. This dynamic adjustment resolves the contradiction by adapting the control strategy to the current operational phase.
Solution Approach 2:
The system changes the parameter of rotational speed difference based on the vehicle's operational state. When transitioning from turning to straight-ahead motion, the controller reduces the target rotational speed difference to a predetermined value or less, which reduces yaw rate and minimizes deviation from the target line while maintaining acceptable turning performance through controlled parameter transition.
2Measurement precision
If the command rotational speed difference is reduced to reduce yaw rate, then the deviation from target line is reduced, but the centrifugal force increases
Solution Approach 1:
The control system performs preliminary action by anticipating the transition from turning to straight-ahead motion and proactively adjusting the command rotational speed difference before the vehicle completes the turning maneuver. By reducing the rotational speed difference in advance, the system minimizes the yaw rate and deviation from target line while managing centrifugal force through controlled deceleration of the turning motion.
Data Source
AI summary
A vehicle includes a controller that calculates left command rotational speed and a right command rotational speed based on a target rotational speed difference that is a difference between a first target parameter and a second target parameter. The controller sets the left and the right command rotational speeds respectively to the left and the right target rotational speeds when the target rotational speed difference is equal to or less than a predetermined value, and sets the left command rotational speed or the right command rotational speed to an rotational speed different from the corresponding target rotational speed so that a command rotational speed difference that is a difference between a first command parameter regarding the left command rotational speed and a second command parameter regarding the right command rotational speed becomes the predetermined value when the target rotational speed difference exceeds the predetermined value.