Wheel Drive Module Control Using Unified Wheel Reference Values
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Solution Overview
Problem
Existing systems for controlling electric motors that jointly drive and steer a wheel face challenges in managing computation load and data transmission, particularly in applications like driverless transport vehicles, where each wheel drive module requires separate control and adaptation due to differing performance data and implementation of driving and steering functions.
Innovation Solution
A method for controlling two electric motors in a wheel drive module using wheel reference values to generate electrical control signals, allowing for unified control of driving and steering functions without requiring adaptation to individual wheel drive modules, by determining motor reference rotational speeds from wheel reference values and gear ratios, and using a central electronics unit to transmit control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two electric motors are used to jointly drive and steer a wheel, then the driving and steering functions can be provided, but the computation load and data quantities to be transmitted increase
Solution Approach 1:
The control system is segmented into a central control unit that handles high-level decision making and wheel-level control units that handle motor control. This segmentation allows the central control to transmit only essential wheel reference values rather than individual motor control commands, reducing overall computational load.
Solution Approach 2:
Wheel reference values serve as an intermediary between the central control and the two electric motors. Instead of the central control directly managing both motors, it transmits wheel reference values that are then converted into motor-specific control signals by the wheel drive module, simplifying the communication protocol.
2Adaptability or versatility
If wheel drive modules differ in design or performance data, then customization for specific applications is possible, but the central control must be adapted to each module type
Solution Approach 1:
The central control unit uses a universal communication protocol that works with all wheel drive modules regardless of their specific design or performance characteristics. The module-specific adaptations are handled locally through the conversion of wheel reference values into motor-specific commands, not in the central control logic.
Solution Approach 2:
The system handles module differences by dynamically adjusting motor-specific parameters (such as motor reference rotational speeds) while maintaining a consistent wheel-level interface. The wheel reference values remain uniform across all modules, but their conversion to motor commands adapts to individual module characteristics.
3Ease of operation
If separate control of electric motors is implemented for each wheel drive module, then precise motor control is achieved, but data transmission quantities increase
Solution Approach 1:
The system extracts the essential wheel-level control parameters (wheel reference values) from the detailed motor control commands. The central control transmits only these extracted wheel reference values, while the detailed motor control is generated locally at the wheel drive module, reducing data transmission requirements.
Data Source
AI summary
The disclosure relates to a method for controlling a first electric motor (M1) and a second electric motor (M2) of a wheel drive module, wherein the wheel drive module comprises a wheel (R) and a speed modulation gearbox (G), and wherein the wheel (R) is drivable about a wheel axis (A) jointly by the first and the second electric motors (M1, M2) by means of the speed modulation gearbox (G) and steerable about a steering axis (L) which is orthogonal to the wheel axis (A), wherein electrical control signals for controlling the first and second electric motors (M1, M2) are determined from wheel reference values which characterize the driving and/or the steering of the wheel (R).