Vehicle Mass Estimator Circuit Using Drive Characteristics in Real Time
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Solution Overview
Problem
Electric vehicles operating in industries face challenges in determining their real-time weight during operation, as weigh stations are often inaccessible, leading to delays and increased costs.
Innovation Solution
A vehicle mass estimator circuit that estimates mass using motor angular velocity, motor torque, and road slope angle, without the need for a scale or dedicated mass sensing system, by collecting inertia and mass information across various operating conditions, and utilizing motor current and accelerometer data to calculate vehicle mass in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the vehicle operator drives to a weigh station to determine vehicle weight, then accurate weight information is obtained, but operational delays and increased costs occur
Solution Approach 1:
The vehicle itself performs the weight measurement function through onboard sensors and processing circuits, eliminating the need to travel to external weigh stations. The vehicle autonomously determines its own weight by measuring motor current, angular velocity, and acceleration, then processes this data to calculate mass, thereby serving its own measurement needs and avoiding operational delays
Solution Approach 2:
The patent replaces the mechanical weighing process at weigh stations with an electronic/inertial measurement system. Instead of using mechanical scales, the system uses motor current sensors, angular velocity sensors, and acceleration measurements combined with inertial calculation to determine vehicle mass, substituting a complex mechanical external system with a simpler electronic onboard system
2Measurement precision
If dedicated mass sensing systems or scales are used to measure vehicle mass, then accurate mass information is obtained, but device complexity and cost increase
Solution Approach 1:
The motor and its control system serve multiple functions: they provide propulsion while simultaneously acting as sensors for measuring current, angular velocity, and acceleration. The existing motor control circuitry is repurposed to also function as the measurement and processing system for mass determination, eliminating the need for separate dedicated mass sensing systems
Solution Approach 2:
The patent uses motor current as an intermediary measurement that indirectly provides mass information. Instead of directly measuring mass with complex sensors, the system measures easily obtainable parameters (current, angular velocity, acceleration) and uses inertial calculation to derive mass, with motor current serving as the key intermediary that links electrical input to mechanical output characteristics
3Loss of information
If weigh station visits are required for mass determination, then mass information is obtained, but productivity and delivery efficiency decrease
Solution Approach 1:
The system continuously measures motor current, angular velocity, and acceleration during normal vehicle operation and continuously updates the mass calculation in real-time. This continuous measurement and processing occurs during every moment of vehicle operation, providing uninterrupted mass information without requiring the vehicle to stop or leave the delivery route, thereby maintaining continuous productive action
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
Enables real-time reporting of vehicle mass, reducing costs and operational delays by providing accurate mass information without the need for frequent weigh station visits, and allowing for robust control of electric vehicles.
Implementation Method 1
inertia and mass information of many vehicles of the same type is collected across various operating conditions... Using the mass of the vehicle, the motor angular velocity, the motor torque, and the road slope angle, the total inertia of the vehicle is estimated
Implementation Method 2
sensed acceleration or without any sensed acceleration... the vehicle mass estimator circuit senses motor current during vehicle operation and estimates a mass of the vehicle using the motor current and acceleration information provided by an accelerometer
Data Source
AI summary
A vehicle includes a vehicle mass estimator circuit. The vehicle mass estimator circuit is configurable to estimate a mass of vehicle during real-time operation of the vehicle without employing a scale or dedicated mass sensing system. The vehicle mass estimator circuit generates the vehicle mass Mv from: (1) an estimated torque or sensed torque, (2) an estimated motor angular velocity or sensed motor angular velocity, and (3) sensed acceleration or without any sensed acceleration. In one embodiment, the vehicle mass estimator circuit senses motor current during vehicle operation and estimates a mass of the vehicle using the motor current without any dedicated acceleration sensor such as an accelerometer. A motor angular velocity is estimated from the motor current. In another embodiment, the vehicle mass estimator circuit senses motor current during vehicle operation and estimates a mass of the vehicle using the motor current and acceleration information provided by an accelerometer.