EV Speed Command Switching for Brake Activation and Torque Saturation
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Solution Overview
Problem
Industrial electric vehicles using speed-control architecture face issues with operability and comfortability due to simple transmission and suspension systems, leading to temporary loss of control when the mechanical brake is activated or when the vehicle is overloaded, resulting in potential accidents.
Innovation Solution
A speed-command generating unit that incorporates a throttle module, computing module, mechanical brake sensing module, braking approach selecting module, trimming module, and switching module to detect and respond to the activated status of the mechanical brake, allowing for switching or trimming of the speed-command to maintain vehicle control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the speed-command unit uses basic acceleration/deceleration function and basic S-curve function, then the control system remains simple, but the system cannot detect mechanical brake activation and cannot provide immediate braking torque
Solution Approach 1:
The patent combines the mechanical brake sensing module with the speed-command generating unit, merging brake detection functionality into the existing control system. This integration allows the system to detect brake activation status and respond appropriately without adding completely separate control systems, thus improving reliability while limiting complexity increase.
Solution Approach 2:
The patent implements feedback by continuously detecting the activated status of the mechanical brake and using this information to adjust the speed-command output. The brake sensing module provides real-time feedback to the switching module, which then modifies the speed-command accordingly, ensuring the system responds to brake activation while maintaining manageable complexity through structured feedback loops.
2Reliability
If the vehicle heavily presses the pedal to accelerate or is overloaded, then the torque saturation occurs and the throttle signal becomes invalid temporarily, but the driver loses control ability and may cause accidents
Solution Approach 1:
The patent applies preliminary action by having the switching module proactively switch to using motor rotating speed as the foundation for speed-command when torque saturation is detected or when brake activation is sensed. This preliminary switching prevents the throttle signal from becoming invalid and maintains driver control ability during overload or heavy acceleration conditions, improving reliability without compromising ease of operation.
3Ease of manufacture
If the industrial vehicle uses simple transmission system and suspension system to reduce cost, then the manufacturing cost decreases, but the operability and comfortability cannot be satisfied
Solution Approach 1:
The patent replaces mechanical improvements with electronic control solutions. Instead of adding complex mechanical transmission or suspension systems to improve operability and comfortability, the patent uses the speed-command generating unit with brake sensing and switching functionality to achieve the desired performance through electronic control, thereby maintaining low manufacturing costs while improving ease of operation.
Data Source
AI summary
A speed-command generating unit incorporated with an electric vehicle having a throttle module, a mechanical brake and a motor is disclosed and includes: a computation module for generating a computation value of a speed-command according to a throttle operating signal from the throttle module, a sensing module for detecting an activated status of the mechanical brake, a selecting module for providing a braking approach selecting signal, a trimming module for setting a trimming flag according to the activated status of the mechanical brake of last cycle, and a switching module connected therewith. The switching module generates different output values of the speed-command for the motor according to different foundations depending on the content of the trimming flag when the mechanical brake is inactivated in this cycle, and generates the output value according to the content of the braking approach selecting signal when the mechanical brake is activated in this cycle.