Torque Current Comparison for Drive Wheel Spin Detection
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Solution Overview
Problem
Industrial trucks face issues with drive wheel spinning and locking during acceleration and braking, leading to excessive wear and poor maneuverability, and existing sensor-based detection systems are costly and prone to inaccuracies due to wear and tear.
Innovation Solution
An electric motor-based industrial truck with a detection system that calculates and compares theoretical and momentary torque currents to detect spinning and locking, allowing for early countermeasures without physical sensors that wear out.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical sensors are used to detect spinning or locking of the drive wheel, then detection capability is provided, but production costs increase and sensor accuracy deteriorates over time due to wear
Solution Approach 1:
The patent replaces physical mechanical sensors with an electronic detection system that calculates theoretical torque current and compares it with momentary torque current. This substitution eliminates mechanical contact components, thereby reducing production costs and eliminating wear-related accuracy deterioration while maintaining reliable detection capability.
Solution Approach 2:
The patent creates a virtual model (theoretical torque current) based on acceleration velocity set point, load, and preset parameters, then compares it with the actual momentary torque current. This copying approach allows detection without physical sensors, avoiding the drawbacks of sensor installation and wear.
2Reliability
If torque current comparison detection is implemented, then detection reliability improves and sensor wear is eliminated, but system complexity increases due to calculation and comparison requirements
Solution Approach 1:
The truck computer is designed to perform multiple functions: controlling the motor controller, calculating theoretical torque current, and comparing currents for spin detection. By making the control system multi-functional, the patent avoids adding separate dedicated detection hardware, thereby maintaining reliability while minimizing system complexity.
Solution Approach 2:
The system uses existing control system components (truck computer, motor controller) to perform the detection function. The truck computer leverages its existing computational capabilities to calculate and compare torque currents, allowing the system to self-diagnose without external or additional specialized equipment.
Data Source
Figure 1
Figure 2a~2d
Figure 3a~4b
AI summary
An industrial fork lift truck comprising an electric motor (3), a motor controller (2) for controlling the electric motor (3) and a truck computer (1) for controlling the motor controller (2), said truck computer (1) comprising a detection system (5) for detecting spinning and/or locking of the drive wheel of the truck characterized in that the detection system (5) is arranged to receive a signal corresponding to the momentary torque current of the motor (3); and further comprising: -a calculation unit (12) for calculating the theoretical torque current of the motor (3); -a comparison unit (13) for comparing the theoretical torque current of the motor (3) and the momentary torque current of the motor (3), wherein the truck computer is arranged to reduce the acceleration or the deceleration of the truck if there is a difference between the theoretical torque current of the motor (3) and the momentary torque current of the motor (3).