Electric Transmission Shift Control for Tooth-to-Tooth Engagement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrically shiftable transmissions face challenges in controlling shift element movements effectively, leading to increased mechanical loads, delayed shift times, and reduced service life due to uncontrollable forces at critical positions like tooth-to-tooth engagement.
Innovation Solution
A method that segments the shift element movement into distinct portions, using position and force as controlled variables, and applies differentiated control modes with closed-loop control to optimize actuator operation, reducing mechanical loads and improving shift performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pneumatic actuation is used to move the shift element, then the shifting process can be achieved, but the force acting on the shift element is barely controllable resulting in strong mechanical loads on transmission components
Solution Approach 1:
The patent replaces the pneumatic actuation system with an electric motor-driven actuator. This substitution allows for precise electronic control of the force applied to the shift element through closed-loop control, eliminating the uncontrollable high forces characteristic of pneumatic systems while maintaining the ability to achieve the shifting process.
Solution Approach 2:
The patent implements closed-loop control with feedback from a position sensor that detects the actual position of the shift element. The control unit continuously compares the actual position with the target position and adjusts the motor's force output accordingly, enabling precise force control throughout the shifting process and preventing excessive mechanical loads on transmission components.
2Device complexity
If a single control mode is used for the entire shifting process, then the control system is simple, but the shift time is increased due to inability to optimize for critical positions like tooth-to-tooth engagement
Solution Approach 1:
The patent segments the shifting process into multiple movement portions based on the detected position of the shift element. Different control modes are assigned to different movement portions: a first control mode is used for normal shifting, while a second control mode is activated for critical positions such as tooth-to-tooth engagement. This segmentation allows optimization of shift time at critical moments without requiring complete redesign of the entire control system.
Solution Approach 2:
The patent implements dynamic switching between different control modes based on the real-time position of the shift element. The control system adapts its behavior by selecting appropriate control modes for different phases of the shifting process, enabling faster response at critical positions while maintaining overall system simplicity through a unified control architecture that handles multiple modes.
3Ease of manufacture
If predetermined parameter sets are used for closed-loop control, then the control implementation is straightforward, but the parameter sets do not sufficiently represent the movement at critical positions resulting in delayed shifting
Solution Approach 1:
The patent employs different parameter sets for different control modes corresponding to different movement portions. The first parameter set is used for normal shifting operations, while a second parameter set is applied for critical positions like tooth-to-tooth engagement. This allows the system to optimize shifting speed at critical moments by changing parameters dynamically, while maintaining ease of implementation through pre-defined parameter sets for each mode.
4Speed
If high forces are applied during shifting to overcome blocking positions, then the shift element can be moved, but the mechanical loads increase and service life of transmission elements is reduced
Solution Approach 1:
The patent uses feedback from the position sensor to detect when the shift element approaches or is at a blocking position. The control unit then adjusts the motor's force output in real-time, applying sufficient force to overcome the blocking position while avoiding excessive forces that would damage transmission components. This feedback-controlled force modulation maintains reliability while achieving necessary movement speed.
Solution Approach 2:
The patent applies preliminary control actions by detecting approaching blocking positions before the shift element actually encounters them. The control system prepares appropriate force levels in advance, smoothing the transition through blocking positions and preventing sudden force spikes that would increase mechanical loads and reduce transmission service life.
Data Source
AI summary
A method (100) for shifting an electrically shiftable transmission (230) for a vehicle (200a), in particular a utility vehicle (200b), includes detecting (105) a position (P) of a shift element (235) of the transmission (230). The method includes determining (110) a plurality of movement portions (301a, 301b, 301c) which relate to a shifting process (300), on the basis of the position (P), and determining (120) a control mode (254a, 256b, 256c) based on the movement portion (301a, 301b, 301c) corresponding to the current position (P). A control signal (255) is determined using the determined control mode (256a, 256b, 256c); and the control signal (255) is output for closed-loop control of the movement of the shift element (235).