Electric Motor AMT Shift Control Using Supervisory Torque Arbitration
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Solution Overview
Problem
Current powertrain control systems for electric motors and automated manual transmissions (AMTs) face challenges in efficiently managing torque and speed synchronization during shift events, leading to potential wear and degradation, and lack effective supervisory control to arbitrate between competing torque requests.
Innovation Solution
The implementation of a supervisory control module (SCM) that arbitrates between various torque requests based on priority parameters, evaluates shift inhibit conditions, and controls the electric motor to execute gear shifts by ramping down and up torque and speed commands, ensuring smooth and efficient shift events while preventing erroneous vehicle operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric motor is used to synchronize input shaft speed during transmission shifts, then shift smoothness is improved, but torque management complexity increases due to competing torque requests from multiple sources
Solution Approach 1:
A supervisory control module is introduced as an intermediary between the transmission controller and motor controller. This module receives torque requests from multiple sources (transmission controller, motor controller, driver), arbitrates them based on priority parameters, and generates a single authoritative torque command. This mediator resolves the complexity of managing competing torque requests while enabling smooth shifts through coordinated motor torque control.
Solution Approach 2:
The supervisory control module dynamically adjusts torque distribution based on real-time operating conditions and shift phase. During shift events, it temporarily modifies torque commands to the electric motor to synchronize input shaft speed, while during normal operation it restores full torque capability. This dynamic adaptation allows the system to balance shift smoothness requirements with overall torque management needs.
2Measurement precision
If supervisory control is implemented to arbitrate torque requests, then torque management accuracy is improved, but control system complexity increases
Solution Approach 1:
The control system is segmented into distinct functional modules: transmission controller for shift logic, motor controller for torque execution, and supervisory control module for arbitration. Each module has a specific responsibility, and the supervisory module uses a structured priority-based arbitration system with predefined parameters. This segmentation improves torque management accuracy through dedicated functions while containing overall system complexity through modular design.
3Loss of energy
If the electric motor functions as an alternator during downshifts to produce electrical energy, then energy recovery is improved, but powertrain control complexity increases
Solution Approach 1:
The supervisory control module dynamically changes the operating parameters of the electric motor based on shift phase and energy recovery opportunities. During downshifts, it adjusts motor speed and torque parameters to enable generator mode operation, converting mechanical energy to electrical energy for storage. This parameter adjustment enables energy recovery while the supervisory module manages the added control complexity through coordinated parameter management across all powertrain components.
Data Source
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AI summary
A vehicle system includes a powertrain including an electric motor operatively coupled with an automated manual transmission and an electronic control system including a gear shift control module, a transmission control module, and a motor control module in operative communication with one another over one or more controller area networks. The electronic control system includes supervisory controls configured to arbitrate between a plurality of motor operation requests received over the one or more controller area networks to select a winning motor operation request, the plurality of motor operation requests including the operator torque request, evaluate one or more shift inhibit conditions, and command the electric motor to provide the winning motor operation request when none of the one or more shift inhibit conditions evaluate as true.