Hand-Guided Power Tool Speed Ramping for Gentle Motor Start
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Solution Overview
Problem
Hand-guided gardening, forestry, and construction processing devices lack advanced features for user comfort and efficient operation, particularly in controlling the rotational speed and slope rates of electric motor drive systems, leading to potential user strain and inconsistent performance.
Innovation Solution
A hand-guided processing device with a user-adjustable operating element and a control device that automatically controls the target slope rate and rotational speed of the electric motor drive system, allowing different settings for maximum target slope rates and rotational speeds based on the position of the operating element, ensuring a gentle start and high user comfort while enabling rapid attainment of desired speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electric motor drive system starts with high rotational speed, then rapid attainment of desired speed is achieved, but pitching and user strain increase
Solution Approach 1:
The control device performs preliminary action by pre-defining multiple allocation curves that map operating element positions to target slope rates and target rotational speeds. These allocations are prepared in advance to guide the motor through optimal acceleration profiles, enabling rapid speed attainment while preventing excessive pitching that would cause user strain.
Solution Approach 2:
The system dynamically adjusts the target slope rate and target rotational speed based on the position of the operating element. The control device continuously monitors the operating element position and dynamically selects/appropriates the corresponding allocation from multiple predefined curves, allowing the system to adapt between gentle start (low slope rate) and rapid acceleration (high slope rate) modes based on user needs.
2Productivity
If the maximum target slope rate is set to high level, then rapid attainment of desired rotational speed is achieved, but pitching of the device increases
Solution Approach 1:
The invention applies parameter changes by providing multiple allocation curves with different characteristics. Each curve represents a different set of parameters relating operating element position to target slope rate and target rotational speed. The control device can select or switch between these different parameter sets (allocations) depending on the desired operating mode, enabling the system to optimize between rapid speed attainment and device stability.
3Device complexity
If the operating element has limited positions, then device complexity is reduced, but adjustment precision and versatility decrease
Solution Approach 1:
The operating element is designed with universal applicability - a single physical component that can assume multiple discrete positions (e.g., first, second, third positions). Each position universally triggers a different allocation curve from the set of predefined curves, allowing one element to control multiple aspects of motor behavior (target slope rate, target rotational speed) across different operating modes, thereby achieving high versatility with minimal complexity.
Data Source
AI summary
A hand-guided gardening, forestry and/or construction processing device includes a processing tool, an electric motor drive system, wherein the electric motor drive system is designed to drive the processing tool, a user-adjustable operating element, and a control device. The control device is designed to control a target slope rate of a rotational speed of the electric motor drive system in dependence on a position of the operating element according to at least one allocation in such a way that maximum target slope rates of the rotational speed differ for different positions.