Dump Truck Route Speed Planning with Wheel Slip Limits
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Solution Overview
Problem
Conveying vehicles, such as dump trucks, face challenges with wheel slip during braking, leading to reduced traveling efficiency and safety due to the need for gradual speed changes to prevent wheel slip, especially when unattended.
Innovation Solution
A conveying vehicle equipped with a vehicle control device that calculates slip rates and slip limit values along a travel route, allowing for the determination of maximum acceleration and deceleration limits to maintain grip, enabling efficient travel by setting target travel speeds based on these calculated values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gradual speed change is used to prevent wheel slip, then wheel slip is suppressed, but traveling efficiency is decreased
Solution Approach 1:
The control device dynamically adjusts acceleration and deceleration commands based on real-time slip rate calculations and predicted road surface friction characteristics. The system transitions from static speed limits to dynamic acceleration/deceleration control that adapts to changing road conditions, allowing optimal performance while preventing wheel slip.
Solution Approach 2:
The system performs preliminary calculation of slip rates and prediction of road surface friction coefficients before executing acceleration or deceleration commands. By predicting future slip risk based on current wheel speeds and road conditions, the control device proactively adjusts commands to prevent wheel slip before it occurs, rather than reacting after slip has started.
2Productivity
If high acceleration/deceleration is used to improve traveling efficiency, then traveling efficiency is improved, but wheel slip occurs making braking impossible
Solution Approach 1:
The control device continuously monitors wheel speeds, calculates slip rates, and uses this feedback to adjust acceleration and deceleration commands in real-time. The system incorporates feedback loops that compare actual wheel performance against predicted friction limits, dynamically modifying control commands to maintain braking capability while maximizing traveling efficiency.
Solution Approach 2:
The system replaces traditional mechanical speed limiting approaches with computational methods for calculating slip rates and predicting friction coefficients. Instead of using fixed mechanical governors or speed limiters, the invention uses electronic sensors, mathematical models, and control algorithms to dynamically determine optimal acceleration and deceleration commands based on real-time road conditions.
3Reliability
If speed limit is changed based on travel path ranking, then wheel slip is suppressed, but braking distance increases
Solution Approach 1:
The system changes from using fixed speed limits based on road rankings to dynamically calculating optimal deceleration commands based on real-time slip rate measurements and predicted friction coefficients. By adjusting deceleration parameters dynamically rather than using fixed speed limits, the system achieves reliable wheel grip while minimizing braking distance through optimized deceleration profiles.
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 solution effectively suppresses wheel slip, ensuring safe and efficient travel by maintaining the grip state, thereby reducing braking distances and improving overall efficiency.
Implementation Method 1
calculates and stores a slip limit value from each of the slip rates, the slip limit value being a friction coefficient value between a road surface and the wheel at a boundary of a grip state and a slip state
Data Source
AI summary
Provided is a conveying vehicle that ensures efficiently travelling while suppressing vehicle slip. A dump truck 100 includes a vehicle body 101 provided with wheels 103 and a vehicle control device 300 and travels on a travel route. The vehicle control device 300 calculates and stores slip limit values at a plurality of positions on the travel route, reads out the slip limit values to calculate at least one of a maximum acceleration and a maximum deceleration of the dump truck 100 at which the wheels 103 is capable of maintaining a grip state against a road surface, and sets a target travel speed at a travel position between the dump truck 100 and a target position according to a target speed at the target position and at least one of the maximum acceleration and the maximum deceleration.