Clutch Speed Control for Smooth Electric Power Equipment Acceleration
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Solution Overview
Problem
Existing electric power equipment, such as lawn mowers, experience sudden accelerations due to deviations in rotational speed when a clutch engages, leading to uncomfortable operation and potential lifting of front wheels, particularly when load changes.
Innovation Solution
A clutch system with a controller that adjusts rotational speed by maintaining a clutch connection speed and using a predetermined rotational speed to stabilize motor operation, preventing sudden accelerations and improving operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the clutch is engaged to switch between transmission and discontinuation of power, then speed adjustment function is achieved, but sudden load is applied to the motor causing rotational speed deviation and sudden acceleration
Solution Approach 1:
The controller predicts the clutch engagement timing based on rotational speed information and interrupt the acceleration command before the clutch actually engages. This preliminary action prevents the sudden load application that would otherwise cause rotational speed deviation and subsequent sudden acceleration, while still maintaining the speed adjustment function.
2Power
If the rotational speed of the travel motor is decreased to suppress load increase on the work motor, then the load on the work motor is reduced, but the travel motor may accelerate rapidly to match command value causing uncomfortable operation
Solution Approach 1:
The controller predicts clutch engagement timing and interrupts the acceleration command in advance. This prevents the scenario where the travel motor would rapidly accelerate to catch up with the command value after clutch engagement, thereby maintaining operability comfort while still managing the load on the work motor.
3Ease of operation
If the clutch engagement timing is delayed to prevent sudden acceleration, then operability is improved, but the speed adjustment response becomes slower
Solution Approach 1:
By predicting the clutch engagement timing in advance and interrupting acceleration before engagement occurs, the system achieves both goals: the speed adjustment response remains timely (not delayed) while sudden acceleration is prevented, improving operability.
Solution Approach 2:
The controller uses rotational speed information as feedback to predict clutch engagement timing. This feedback mechanism enables the controller to determine the optimal moment to interrupt acceleration, balancing the speed adjustment response with operability improvement.
Data Source
AI summary
An electric power equipment includes a drive source, a clutch provided in a power transmission path between the drive source and the travel unit and a controller for controlling an operation of the drive source. Wherein the controller is configured that in a process of increasing a speed in accordance with a rotational speed command value, when a rotational speed of the drive source reaches the clutch connection rotational speed, the increasing of the speed in accordance with the rotational speed command value is interrupted, and when the rotational speed of the drive source reaches a predetermined rotational speed, the increasing of the speed in accordance with the rotational speed command value is performed.