Work Vehicle Shuttle Control for Shock-Suppressed Direction Switching
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Solution Overview
Problem
Existing work vehicles experience responsiveness issues and shock during shuttle motions due to throttle-controlled travel pump switching, making it difficult to accurately achieve operator-intended vehicle motions.
Innovation Solution
A work vehicle system with a controller that determines target braking forces and displacements based on operator inputs, using sensors to manage travel pump and motor operations, thereby suppressing shock and improving responsiveness during shuttle motions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the pump control valve switches quickly to change the skew plate angle of the travel pump during shuttle motion, then the responsiveness of direction switching is improved, but shock occurs in the vehicle
Solution Approach 1:
The control device determines that the work vehicle is in a shuttle motion state before the pump control valve switching is executed, and in advance determines a target braking force based on the shuttle motion. This preliminary determination of braking force allows the system to prepare for shock suppression before the actual direction switching occurs, resolving the contradiction between fast switching and shock prevention
Solution Approach 2:
The control device uses sensors to detect the actual traveling direction and operating position, determines whether the vehicle is in shuttle motion, and adjusts the target braking force accordingly. This feedback mechanism continuously monitors the vehicle state and dynamically adjusts the braking force to suppress shock while maintaining responsive direction switching
2Object-affected harmful factors
If a throttle is provided in the return circuit to suppress sudden change in skew plate angle, then shock is suppressed, but the responsiveness of control during shuttle motion deteriorates
Solution Approach 1:
The invention replaces the mechanical throttle-based shock suppression system with an electronic control system that determines target braking force based on detected shuttle motion. This substitution eliminates the need for physical throttles while achieving both shock suppression and maintained responsiveness through electronic actuation of the braking system
Solution Approach 2:
The control device dynamically changes the braking force parameter based on the detected shuttle motion state. By adjusting the target braking force as a controllable parameter in response to shuttle motion detection, the system achieves adaptive shock suppression without the fixed characteristics of a mechanical throttle, thereby maintaining responsiveness
3Measurement precision
If the controller determines target braking force and travel pump displacement based on operator inputs during shuttle motion, then control accuracy is improved, but the system complexity increases
Solution Approach 1:
The control device integrates multiple functions into a single system: it detects shuttle motion, determines target braking force, controls travel pump displacement, and manages shock suppression all through one controller. This multi-functionality approach improves control accuracy while minimizing the increase in overall system complexity by consolidating control functions rather than adding separate dedicated systems
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
Accurately achieves operator-intended vehicle motions while suppressing shock during shuttle motions, enhancing responsiveness and control accuracy.
Implementation Method 1
The hydraulic fluid discharged by the travel pump is supplied to the travel motor through the hydraulic circuit. The travel motor is connected to a travel device of the work vehicle and the work vehicle travels due to the travel motor being driven.
Implementation Method 2
The pump control cylinder 102 changes the discharge direction and the displacement of the travel pump 101 in response to a pilot pressure inputted from the pump control valve 103.
Data Source
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AI summary
The controller is configured to determine whether the vehicle is in a shuttle motion from the operating position of the forward/reverse travel operating member and the actual traveling direction of the vehicle. The controller is configured to determine a target braking force when the vehicle is in the shuttle motion. The controller is configured to determine a target displacement of the travel pump and/or a target displacement of the travel motor based on the target braking force.