Work Vehicle Torque Correction for Smooth Starts and Load Response
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Solution Overview
Problem
Work vehicles experience excessive acceleration when output torque is based solely on accelerator operation, leading to reduced riding comfort and inadequate torque on rough roads or steep slopes, resulting in trade-offs such as decreased vehicle speed.
Innovation Solution
A control device and method that determine and apply the required output torque within an allowable range based on the vehicle's state, using a combination of sensors and control units to adjust engine and transmission settings, ensuring the torque is appropriate for the intended operation without generating excessive acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If output torque is determined based on accelerator operation, then the vehicle can generate high torque for work operations, but excessive acceleration occurs contrary to operator intention
Solution Approach 1:
The control device calculates actual acceleration from vehicle speed changes and feeds this information back to adjust the engine torque command. When actual acceleration exceeds the target acceleration derived from accelerator operation, the torque command is reduced to match the operator's intended acceleration, preventing excessive acceleration while maintaining power availability.
Solution Approach 2:
The system dynamically adjusts the torque command based on real-time acceleration feedback. The torque command is modified according to the difference between actual and target acceleration, allowing the system to adapt torque output to match operator intention while maintaining the capability to deliver high torque when needed for work operations.
2Ease of operation
If output torque is restricted to prevent excessive acceleration, then riding comfort improves, but vehicle speed decreases due to insufficient torque on rough roads
Solution Approach 1:
The system uses acceleration feedback to determine when torque restriction is necessary. When actual acceleration matches target acceleration, full torque availability is maintained. Torque restriction is applied only when actual acceleration exceeds target acceleration, ensuring riding comfort is maintained without unnecessarily limiting vehicle speed on rough roads where high torque is needed.
Solution Approach 2:
The torque command parameter is dynamically adjusted based on acceleration feedback. The system changes the torque parameter from the initially calculated value to a corrected value that prevents excessive acceleration while maintaining sufficient torque for maintaining vehicle speed on challenging terrain.
3Power
If high torque is applied for work operations, then work capability improves, but unnecessary strong acceleration occurs during travel
Solution Approach 1:
The control device continuously monitors actual acceleration and compares it to target acceleration. When actual acceleration exceeds target acceleration during travel, the feedback mechanism reduces the engine torque command to eliminate the excessive acceleration, while still maintaining the capability to apply high torque when needed for work operations.
Solution Approach 2:
The control device acts as an intermediary between the accelerator operation and the engine torque output. It calculates the torque command based on accelerator position but modifies this command using acceleration feedback to prevent harmful excessive acceleration, thereby mediating between operator input and actual torque application.
Data Source
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AI summary
A required output torque determination unit determines a required output torque of a power transmission device based on an operation amount of an operation device and a traveling speed of a work vehicle. A traveling load estimation unit estimates a traveling load torque related to a traveling load on the work vehicle based on a torque of a drive source, a rotation speed ratio of the power transmission device, and a rotation speed of an output shaft. A required output torque correction unit corrects the required output torque such that the required output torque is included in an allowable output torque range including an estimated traveling load torque. A drive source control unit outputs a control signal for the drive source based on a corrected required output torque.