Wheel Torque Allocation Using Distributed Brake-Motor Control
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Solution Overview
Problem
Current systems for controlling vehicle wheels with multiple actuators, such as electric motors and service brakes, require complex central control to manage torque allocation, making the task cumbersome and inefficient.
Innovation Solution
A system where a primary controller provides a desired torque split or regenerative braking parameter to secondary controllers at each wheel, allowing them to optimize the allocation between actuators based on predefined criteria, simplifying the central control's task and enabling effective conflict resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the central controller manages torque allocation for multiple actuators at each wheel, then the control precision is improved, but the device complexity increases
Solution Approach 1:
The control system is segmented into a central controller that sends target values and wheel-end control units that perform local optimization. The central controller divides the torque allocation task by sending target torque values and regenerative braking ratios to each wheel independently, allowing local controllers to handle the complex actuator coordination without overloading the central system.
Solution Approach 2:
The control architecture transitions from a flat centralized structure to a hierarchical multi-dimensional structure. The central controller operates at one level sending targets, while wheel-end controllers operate at another level performing local optimization, creating a distributed control dimension that reduces central complexity while maintaining precision.
2Measurement precision
If the central controller allocates torque requests to all torque actuators individually, then the control accuracy is improved, but the ease of operation deteriorates
Solution Approach 1:
The wheel-end control units are empowered to autonomously allocate torque to individual actuators based on local conditions and received targets. Each wheel-end controller independently determines the optimal torque distribution among its actuators without requiring centralized micromanagement, making the system easier to operate while maintaining accuracy through local intelligence.
3Measurement precision
If the central controller considers both service brake actuator and electric motor actuator as separate actuators, then the control precision is improved, but the productivity deteriorates
Solution Approach 1:
The control task is segmented so the central controller only sends target values rather than individually managing each actuator. This segmentation allows the central controller to maintain precise control objectives while wheel-end controllers handle the computationally intensive actuator allocation, improving overall system productivity.
Data Source
AI summary
A comprises a vehicle control unit, VCU, and a control module, CM, configured to control the torque actuators. The VCU is configured to send to the CM a parameter request and a desired recuperation power or a desired parameter split ratio. If the CM determines that these are conflicting targets, then based on one or more predefined criteria, the CM will apply a parameter value and allocate a recuperation power or a parameter split ratio such that the applied parameter value is different from the requested one and/or the allocated recuperation power or parameter split ratio is different from the desired one. A method of controlling a wheel is also disclosed.