Vehicle Speed Control During Power Failure
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Solution Overview
Problem
Hybrid forklift trucks face acceleration response lag and excessive battery discharge due to power generation limitations during vehicle acceleration, leading to potential speed control issues and power failures, which can result in unsafe driving conditions.
Innovation Solution
A method and apparatus that monitor power status and control vehicle speed by maintaining a stable speed during power failures, allowing continuous driving by limiting speed increases and stabilizing power through regenerative braking and load reduction, enabling the vehicle to maintain a predetermined speed even after power stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the acceleration limit unit restricts acceleration command according to battery discharge power, then battery discharge is controlled within available range, but acceleration response lag occurs and speed control is limited in specific situations only
Solution Approach 1:
The patent applies dynamics by making the speed limit value changeable based on vehicle operating conditions. Instead of using a fixed speed limit, the system dynamically adjusts the speed limit according to the current driving state, power availability, and battery status. This allows the acceleration limit unit to adapt to different situations, providing both reliable battery control and appropriate acceleration response across various operating conditions.
2Reliability
If acceleration command is restricted by acceleration limit unit, then battery discharge power is controlled, but speed increase is not properly limited during power failure
Solution Approach 1:
The patent applies preliminary action by pre-establishing a speed limit value that is applied when power failure is detected. The control unit is configured to limit the acceleration command based on this predetermined speed limit when a power failure occurs, ensuring that speed increase is controlled even during unexpected power loss events. This preliminary control mechanism ensures safety without requiring complex real-time calculations during the failure event.
3Device complexity
If speed limit is maintained at constant slope only in specific situations, then acceleration control is simplified, but continuous speed control during power failure is not achieved
Solution Approach 1:
The patent applies universality by making the acceleration limit unit serve multiple functions. It not only controls acceleration during normal operation based on battery discharge power but also limits speed increase during power failure events. The control unit integrates both functions into a single control mechanism, allowing the system to maintain continuous and safe operation across different failure scenarios without requiring separate control systems for each situation.
Data Source
AI summary
Provided is a method of driving a vehicle including: monitoring a power status of the vehicle; and if, during the monitoring the power status of the vehicle, a power failure is detected and a first acceleration command is received, controlling the vehicle to travel at a first speed corresponding to the first acceleration command.