Vehicle Mass Estimation Using Torque and Road Gradient Changes
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Solution Overview
Problem
Existing methods for calculating vehicle mass in commercial vehicles face challenges such as difficult sensor installation, damage from harsh environments, and inaccuracies due to external conditions like wind resistance and road friction, especially under uniform speed conditions, leading to unreliable mass calculations.
Innovation Solution
A method involving real-time collection of engine torque and electronic horizon data, with specific criteria for selecting sampling points based on gradient and torque differences, followed by a simplified calculation formula to determine vehicle mass, suitable for constant speed conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor acquisition method is used to obtain vehicle mass, then mass data can be obtained, but installation is difficult and sensor is easily damaged due to harsh external operating environment
Solution Approach 1:
The patent replaces physical sensors with a computational method that uses engine torque data and electronic horizon data to calculate vehicle mass. This substitutes mechanical/sensor-based measurement with a software-based calculation system, avoiding sensor installation and damage issues while maintaining mass measurement capability
Solution Approach 2:
The patent introduces engine torque and electronic horizon data as intermediary parameters to indirectly determine vehicle mass. Instead of directly measuring mass with sensors, the system uses these intermediate measurements (torque from engine control unit, gradient from electronic horizon) to compute mass through a calculation formula
2Measurement precision
If dynamic estimation method is used to calculate vehicle mass, then mass can be estimated, but calculation is difficult due to influence of external operating conditions and environmental parameters
Solution Approach 1:
The patent extracts and eliminates the influence of environmental parameters (wind resistance, road friction) from the calculation by using the difference method between two sampling points. By taking the differential of the force balance equation, these external parameters that remain relatively constant are cancelled out, leaving only the terms involving mass, acceleration, and gradient that can be directly measured or calculated
Solution Approach 2:
The patent changes the calculation approach from using absolute values to using differential values (changes) between two sampling points. This parameter transformation allows the system to work with measurable quantities (change in torque, change in acceleration, change in gradient) while eliminating the need to know or estimate constant environmental parameters
3Measurement precision
If difference between adjacent states is used to offset environmental parameters, then mass can be calculated, but denominator is differential value of acceleration which is only suitable for large changes in acceleration, not suitable for uniform speed or uniform acceleration conditions
Solution Approach 1:
The patent makes the calculation method adaptive to different driving conditions by dynamically selecting sampling points based on whether they meet the gradient difference threshold criterion. The system can handle both dynamic conditions (large gradient changes) and steady-state conditions (uniform speed on level roads) by requiring significant gradient variation between sampling points, which naturally occurs in hilly terrain but not on flat roads
4Ease of operation
If vehicle runs at constant speed, then uniform speed conditions are common especially on highways, but acceleration is 0 making denominator of dynamic formula 0 and formula cannot solve mass
Solution Approach 1:
The patent prepares for constant speed conditions by pre-establishing the gradient difference criterion for sampling point selection. Before attempting mass calculation, the system checks whether the gradient difference between sampling points exceeds the threshold, ensuring that the calculation is only performed when gradient variation is sufficient to provide a non-zero denominator, thus preventing division by zero errors
Data Source
Figure 1
AI summary
The present disclosure relates to a method for computing a vehicle mass, a terminal device and a storage medium. The method includes: S1: collecting engine torque data and electronic horizon data of a vehicle in real time, and setting a time interval T; S2: determining whether two sampling points whose gradient value difference between a post sampling point and a previous sampling point is greater than a gradient value difference threshold exist within the time interval T; and then entering S3 until they exist; S3: determining whether the two sampling points are on a same road; if so, entering S4; otherwise, returning to S2; S4: determining whether the road between the two sampling points is a straight road; if so, entering S5; otherwise, returning to S2; S5: determining whether a difference between engine torques corresponding to the post sampling point and the previous sampling point is greater than a torque difference threshold; if so, entering S6; otherwise, returning to S2; S6: calculating the vehicle mass according to the engine torques and gradient values corresponding to the two sampling points. The present disclosure can calculate the vehicle mass when driving at a constant speed, and is suitable to be used in the hilly working conditions with large terrain changes in combination with the electronic horizon.