Dynamic Speed Threshold for Human-Powered Vehicle Motor Control
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Solution Overview
Problem
Existing human-powered vehicle control systems fail to adjust motor assistance effectively based on the vehicle's state and road conditions, leading to inappropriate timing of propulsion assistance.
Innovation Solution
A human-powered vehicle control device with an electronic controller that adjusts the predetermined speed for motor assistance based on various states of the vehicle, such as traveling speed, angle, and road conditions, allowing for precise control of motor assistance to match the vehicle's state and road conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the motor assists propulsion at a fixed predetermined speed threshold, then the control logic is simple, but the assistance timing is inappropriate for varying vehicle states and road conditions
Solution Approach 1:
The predetermined speed threshold is transformed from a fixed value to a dynamically adjustable parameter that changes based on vehicle state (turning, straight travel, braking) and road conditions (slope, curvature). The electronic controller continuously monitors these parameters and adjusts the threshold accordingly, allowing the system to adapt to varying conditions while maintaining a relatively simple control structure.
Solution Approach 2:
The system changes the speed parameter dynamically based on different operating conditions. When the vehicle is turning, the predetermined speed is lowered; when braking, it is reduced further; when on slopes or curved roads, it is adjusted to match the road gradient and curvature. This parameter change approach enables adaptability without requiring a completely complex control system.
2Stability of the object's composition
If the predetermined speed is lowered during turning, then vehicle stability is improved, but motor assistance may be restricted too early
Solution Approach 1:
The predetermined speed threshold dynamically adjusts based on the turning state. During active turning, the threshold is lowered to prevent motor assistance that could destabilize the vehicle. Once the turning state ends and the vehicle returns to straight travel, the threshold automatically increases, allowing motor assistance to resume. This dynamic adjustment ensures both stability during turning and adequate assistance duration overall.
Solution Approach 2:
The motor assistance is periodically enabled and disabled based on the turning cycle. During the turning phase, assistance is restricted; during straight travel phases, assistance is enabled. This periodic modulation of motor assistance aligns with the natural cycling between turning and straight travel, maintaining stability while preserving productivity over the complete travel cycle.
3Productivity
If motor assistance is provided during braking, then propulsion is maintained, but vehicle control and safety are compromised
Solution Approach 1:
The system applies preliminary anti-action by detecting the braking state and immediately restricting motor assistance before it can interfere with the braking process. The electronic controller monitors brake operation and preemptively disables motor propulsion assistance, preventing any potential conflict between motor force and braking force that could compromise control safety.
Solution Approach 2:
The restriction of motor assistance during braking, while reducing immediate propulsion, converts a potentially harmful situation into a beneficial one by ensuring safe and predictable braking performance. The system prioritizes control safety over propulsion maintenance during braking, and the motor assistance is restored after braking completes, ensuring both safety and productivity are achieved at appropriate times.
Data Source
AI summary
A human-powered vehicle control device includes an electronic controller that is configured to control a motor that assists in propulsion of a human-powered vehicle and that stops assisting in the propulsion of the human-powered vehicle at a timing suitable for a state of the human-powered vehicle or a state of a road. The electronic controller drives the motor in correspondence with a human drive force upon determining a traveling speed of the human-powered vehicle is less than a predetermined speed that is higher than 0 km/h. The electronic controller varies the predetermined speed in correspondence with at least one of a state of the human-powered vehicle and a state of a road on which the human-powered vehicle travels. The electronic controller does not assist the propulsion of the human-powered vehicle upon determining the traveling speed of the human-powered vehicle is greater than or equal to the predetermined speed.