Electric Power Steering Control Circuit for Auxiliary Power Management
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Solution Overview
Problem
In electric power steering devices, continuous use of the auxiliary power source for extended periods or high steering assist forces can lead to sudden power depletion, causing discomfort due to abrupt changes in steering effort, and inefficient utilization of the auxiliary power source.
Innovation Solution
An electric power steering device with a control circuit that adjusts the power supply to the motor from the auxiliary power source based on the remaining energy, gradually reducing the steering assist force to prevent sudden changes and optimize energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the auxiliary power source is used continuously for extended periods or high steering assist force is provided, then the steering assist function is maintained, but the auxiliary power source becomes depleted suddenly causing discomfort and inefficient energy utilization
Solution Approach 1:
The patent applies dynamics by making the steering assist force adjustable and variable over time. The control circuit dynamically changes the assist force based on the remaining energy level in the auxiliary power source, transitioning from high assist force when energy is sufficient to reduced assist force as energy depletes. This dynamic adjustment prevents sudden power cessation while optimizing energy utilization throughout the discharge process.
Solution Approach 2:
The patent implements parameter changes by modifying the steering assist force parameter according to the energy state of the auxiliary power source. The control circuit monitors the voltage or charge level and adjusts the assist force parameter accordingly, creating a relationship between energy availability and assist force magnitude. This parameter adaptation allows extended operation while preventing complete energy depletion.
2Ease of operation
If the steering assist force is gradually reduced to prevent sudden power cessation, then driver comfort is improved, but the effective utilization of auxiliary power source energy may be compromised
Solution Approach 1:
The patent employs feedback by continuously monitoring the energy state of the auxiliary power source and using this information to adjust the steering assist force. The control circuit creates a closed-loop system where the output (assist force) is regulated based on the input (remaining energy). This feedback mechanism ensures that assist force is reduced smoothly to maintain comfort while maximizing the use of available energy before complete depletion.
Solution Approach 2:
The patent applies preliminary action by proactively reducing the steering assist force before the auxiliary power source is completely depleted. Instead of waiting for energy exhaustion, the system anticipates depletion by gradually lowering assist force as energy levels decrease, preventing sudden power loss and ensuring smooth transition to battery power or complete shutdown.
Data Source
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AI summary
There is provided a controller for a steering device that makes it possible to prevent sudden ceasing of steering assisting power by effectively utilizing an auxiliary power source. An electric power steering device that generates steering assist force by a motor includes a battery for supplying electric power to the motor, an auxiliary power source that supplies the motor with electric power, and a control circuit for controlling a power supply to the motor. In the event of a breakdown of the battery, the control circuit adjusts a power supply to the motor from the auxiliary power source according to an amount of energy remaining in the auxiliary power source so as to reduce steering assist force.