Electric Vehicle Brake Actuation for Control Error Safety
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Solution Overview
Problem
Electric vehicles at standstill may experience undesired movement due to control device errors, posing safety risks if they cannot be adequately restrained.
Innovation Solution
Actuating a brake device, such as a disk brake, wheel brake, or gear lock, to prevent movement exceeding 10 cm in case of control device errors, ensuring the vehicle remains stationary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electric motor is switched off during standstill, then energy consumption is reduced, but control device errors may cause undesired movement
Solution Approach 1:
The brake device is actuated in advance or simultaneously with motor shutdown to counteract any potential undesired movement before it can occur. This preliminary protective action ensures that even if control errors cause the motor to produce torque, the brake prevents the vehicle from moving more than 10 cm.
Solution Approach 2:
The brake device is activated as a preparatory safety measure when the vehicle comes to a standstill. This preliminary action ensures the vehicle is secured before any potential control errors could cause movement, allowing the motor to be switched off for energy savings while maintaining safety.
2Reliability
If the brake device is actuated to prevent movement, then safety is improved, but the method requires independence from the control device
Solution Approach 1:
The control system is segmented into two independent parts: the primary control device for normal operation and a separate safety mechanism for error detection and brake actuation. This segmentation allows the safety function to operate independently when control errors occur, without requiring the primary control device to be functional.
Solution Approach 2:
An intermediary safety mechanism is introduced between the control device and the brake device. This intermediary monitors control device status and can independently activate the brake if errors are detected, serving as a mediator that ensures safety even when the primary control fails.
Data Source
AI summary
A method for operating an electric vehicle, the electric vehicle having an electric motor and a brake device, and the electric motor and the brake device being capable of being influenced by a control device. When the electric vehicle is at a standstill, when there is an error of the control device, the brake device is actuated so that the electric vehicle cannot move, or at least can move only to a very limited extent.