Electric Transmission Shift Control for Low-Impact Gear Engagement
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Solution Overview
Problem
Existing electrically shiftable transmissions in vehicles experience noise and functional impairment due to uncontrolled impacts and jamming during gear shifts, which are not adequately addressed by prior methods.
Innovation Solution
A method involving the determination of motion profiles for shifting elements in electrically shiftable transmissions, using polynomial relationships and constraints to control position, velocity, and acceleration, ensuring jerk-free motion and controlled engagement to minimize noise and prevent jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple target position adjustment method is used for the electric shifting actuator, then the control system remains simple, but the shifting element causes impact noise and may jam in tooth-to-tooth position
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal motion profiles in a memory unit before shifting operations. The control unit selects and applies appropriate motion profiles (constant velocity, constant acceleration, or polynomial) based on the current shifting state, allowing the system to execute complex controlled motion without real-time computational complexity. This resolves the contradiction by preparing control parameters in advance, enabling smooth impact-free shifting while maintaining simple control logic during operation.
Solution Approach 2:
The patent implements dynamics by transitioning from static target position control to dynamic motion profile control. The control unit continuously adjusts the actuator's velocity and acceleration based on the selected motion profile, adapting the shifting behavior to different phases of the engagement process. This dynamic control enables the system to minimize impact velocities and avoid tooth-to-tooth jamming while keeping the control structure manageable through pre-defined profile selection.
2Speed
If the shifting element moves quickly to reach target position, then shifting speed increases, but impact velocity increases causing noise and potential damage
Solution Approach 1:
The patent applies periodic action through multi-phase motion profiles that divide the shifting process into distinct stages: initial engagement phase, intermediate engagement phase, and final engagement phase. Each phase has specific velocity and acceleration characteristics optimized for its purpose. The control unit transitions between these phases based on engagement progress, enabling fast overall shifting while controlling impact velocities at critical moments through the structured periodic nature of the motion sequence.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting velocity and acceleration parameters throughout the shifting process. Different motion profiles offer different parameter characteristics: constant velocity for steady movement, constant acceleration for rapid positioning, and polynomial profiles for smooth transitions. The control unit selects and switches between these parameter sets based on the shifting state, achieving high shifting speed while maintaining low impact velocities through coordinated parameter variation.
3Object-affected harmful factors
If polynomial motion profiles are used to achieve jerk-free motion, then noise and jamming are reduced, but computational complexity and control system requirements increase
Solution Approach 1:
The patent resolves the complexity issue through preliminary action by pre-calculating polynomial motion profiles and storing them in a memory unit. The control unit simply retrieves and applies the appropriate pre-computed profile based on the current shifting state, avoiding the need for real-time polynomial calculation. This approach enables jerk-free motion with polynomial profiles while keeping the control system simple, as the complex computational work is performed offline during system setup or initialization.
Data Source
AI summary
A method (100) for shifting an electrically shiftable transmission (230) for a vehicle (200a), such as a commercial vehicle, is provided. The method (100) includes ascertaining (110) a constraint (310) relating to a shifting element (235) of the transmission (230) and determining (120) a motion profile (300) for the shifting element (235). The motion profile (300) defines a position (P) of the shifting element (235) as a function of time (t). The method further includes outputting (130) a regulation signal (255) for regulating the position of the shifting element (235) on the basis of the motion profile (300).