Switching Controller Backlash Compensation for Detent Positioning
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Solution Overview
Problem
The existing shift range switching devices for automatic transmissions face challenges in accurately detecting the position of the detent plate due to mechanical backlash and play, as well as errors in the output angle detecting unit, which are influenced by manufacturing tolerances and temperature changes, leading to inconsistent accuracy in switching positions.
Innovation Solution
A switching controller is introduced that includes a detent device with a first and second member, an electric actuator with a rotor and reduction gear, and a main controller that calculates and compensates for backlash between the rotor and detent plate using specific regions of low angle change, incorporating this information into motor control to ensure precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an output angle detecting unit using magnet and hall IC is used to detect the output angle of the output shaft, then the shift range can be detected, but the detection accuracy deteriorates due to manufacturing tolerances, temperature changes, and magnetic field variations
Solution Approach 1:
The patent replaces the magnetic detection system (magnet and hall IC) with a mechanical detection system using a detection plate that has detection grooves. The detection plate mechanically detects the output angle through physical engagement with the output shaft, eliminating sensitivity to temperature and magnetic field variations while maintaining detection accuracy.
Solution Approach 2:
The detection plate creates a mechanical copy or representation of the output shaft's angular position through its grooves and engagement features. This mechanical copying system provides a reliable physical counterpart to the magnetic detection system, ensuring accurate position detection independent of environmental factors.
2Ease of manufacture
If mechanical backlash and play are present in the transmission between the output shaft and detent plate, then the system can accommodate manufacturing tolerances, but the detection accuracy of the detent plate position deteriorates
Solution Approach 1:
The detection plate is designed with pre-configured detection grooves and engagement features that establish a precise mechanical relationship with the output shaft before operation. This preliminary mechanical configuration ensures accurate position detection while accommodating manufacturing tolerances through the inherent play and backlash in the mechanical connection.
Data Source
AI summary
A second member and a first member are applied with bias force to mechanically engage with each other at one of detent positions defining relative positions therebetween. An electric motor rotating a rotor therein when being supplied with electricity. Rotation of the rotor is transmitted to an output shaft manipulating the first member. A main controller controls the electric motor to switch the one of the plurality of detent positions. A rotor angle detecting unit detects rotor angle of the rotor. An output angle detecting unit detects output angle of the output shaft. The main controller includes a backlash calculating unit that calculates a backlash amount between the rotor and the first member in accordance with at least one of occurrence of a first region, in which change in the output angle is small with respect to change in the rotor angle, and a range of the rotor angle in the first region. The main controller incorporates the backlash amount into the control of the electric motor.